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Commercial and US Government Launch Vehicles => Sierra Space Dream Chaser Section => Topic started by: Chris Bergin on 07/12/2012 04:39 pm

Title: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Chris Bergin on 07/12/2012 04:39 pm
DISCUSSION thread for SNC's Dream Chaser as it progresses to the end of CCDev-2.

Articles - in order:

Banking on Dream Chaser:
http://www.nasaspaceflight.com/2005/11/spacedev-banking-on-dream-chaser/

Dream Chaser agreement with ULA Atlas V:
http://www.nasaspaceflight.com/2007/04/spacedev-announce-dream-chaser-agreement-with-ula-atlas-v/

Dream Chaser Progress Milestones:
http://www.nasaspaceflight.com/2011/08/nasa-ccdev-2-partners-reveals-progress-milestones/

Dream Chaser making impressive progress ahead of CCDev-3:
http://www.nasaspaceflight.com/2012/01/dream-chaser-impressive-progress-ahead-ccdev-3/

SNC Captive Carry test sees Dream Chaser take flight:
http://www.nasaspaceflight.com/2012/05/snc-captive-carry-test-dream-chaser-take-flight/

Dream Chaser passes PDR, heads towards integrated system testing:
http://www.nasaspaceflight.com/2012/06/dream-chaser-passes-pdr-integrated-system-testing/

SNC outline Dream Chaser’s Enterprise-style landing test approach:
http://www.nasaspaceflight.com/2012/06/snc-dream-chasers-enterprise-test-approach/

Sierra Nevada’s 5-year partnership with NASA – Progress on Dream Chaser:
http://www.nasaspaceflight.com/2012/06/sierra-nevadas-5-year-partnership-nasa-progress-dream-chaser/

Dream Chaser Nose Landing Gear Skid System ready for landing tests:
http://www.nasaspaceflight.com/2012/07/dream-chaser-nlg-skid-system-landing-tests/

Forum Threads:

Article Specific Threads in the Commercial Crew Forum Section:
http://forum.nasaspaceflight.com/index.php?board=56.0

New SNC Dream Chaser UPDATE Thread:
http://forum.nasaspaceflight.com/index.php?topic=29416.0

L2:

Major L2 Master Thread for SNC Dream Chaser (Photos, Graphics, Videos, Updates):
http://forum.nasaspaceflight.com/index.php?topic=27834.0

Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: demorcef on 07/12/2012 04:42 pm
I really hope this thing actually flies in the near future. It sounds like SNC is making fantastic progress so far. Dyna Soar reborn!
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Lars_J on 07/12/2012 04:46 pm
I've always been a bit skeptical about DC, but the recent progress has been encouraging.

I think the sight of DC doing actual free flying landing tests will garner significant attention. A lot. I look forward to seeing it as soon as possible.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Soaring Habu on 07/12/2012 07:03 pm
I'm delighted to see that Dream Chaser is making progress; at least there's a spaceplane successor to the Shuttles as well as the new capsules.

I do have a few minor reservations about Dream Chaser's skid strip nose gear though; how does a pilot steer Dream Chaser after touchdown, for example to compensate for a crosswind or a flat tyre on the main gear?

I'm not sure what material the skid strip would be made from, but wouldn't a solid piece of whatever material is used suffer too much friction scraping against the runway and possibly be damaged? Will the skid strip be replaced after every landing like the Shuttle Orbiter's tyres or not?

Also, how would Dream Chaser be moved to the hangar/OPF after landing; would it be towed like the Shuttle Orbiter, but with the skid strip scraping on the ground, towed on its main gear only with the skid strip raised off the ground somehow, or loaded onto a wheeled transporter similar to the one used to roll the Shuttle Orbiters over to the VAB for stacking?

???
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Rocket Science on 07/12/2012 07:15 pm
I'm delighted to see that Dream Chaser is making progress; at least there's a spaceplane successor to the Shuttles as well as the new capsules.

I do have a few minor reservations about Dream Chaser's skid strip nose gear though; how does a pilot steer Dream Chaser after touchdown, for example to compensate for a crosswind or a flat tyre on the main gear?

I'm not sure what material the skid strip would be made from, but wouldn't a solid piece of whatever material is used suffer too much friction scraping against the runway and possibly be damaged? Will the skid strip be replaced after every landing like the Shuttle Orbiter's tyres or not?

Also, how would Dream Chaser be moved to the hangar/OPF after landing; would it be towed like the Shuttle Orbiter, but with the skid strip scraping on the ground, towed on its main gear only with the skid strip raised off the ground somehow, or loaded onto a wheeled transporter similar to the one used to roll the Shuttle Orbiters over to the VAB for stacking?

???
Differential braking and a nose gear dolly...
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: zerm on 07/12/2012 11:32 pm
The skid does about the same for a pilot as any nosewheel in the initial portion of the landing of a high performance aircraft- i.e. stay straight and don't shimmy. That is all you want it to do- period.

So far a a cross wind, the best way to handle it is to simply avoid it as much as you can. in other words do not crab well (see Milt Thompson's "Flying Without Wings" and Dale Reed's "Wingless Flight"). Thus, in short, you select landing times and sites where the crosswind is a very low factor.

So far as a "blown tire" you do what any pilot would do- hope not. No matter if you had a skid or a nosewheel, in the case of a blown main, it would make very little differance in the outcome IMO. In fact the skid would likely have greater surface to runway friction and thus would likely help slghtly more as far as stability in the landing roll is concerned. Things that normally blow tires are almost nonexistant in the environment that a spacecraft would be operational in, however (FOD heavy wear from repeated cycles -(because new tires are cheap) and so on).
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Star One on 07/13/2012 06:57 pm
The skid does about the same for a pilot as any nosewheel in the initial portion of the landing of a high performance aircraft- i.e. stay straight and don't shimmy. That is all you want it to do- period.

So far a a cross wind, the best way to handle it is to simply avoid it as much as you can. in other words do not crab well (see Milt Thompson's "Flying Without Wings" and Dale Reed's "Wingless Flight"). Thus, in short, you select landing times and sites where the crosswind is a very low factor.

So far as a "blown tire" you do what any pilot would do- hope not. No matter if you had a skid or a nosewheel, in the case of a blown main, it would make very little differance in the outcome IMO. In fact the skid would likely have greater surface to runway friction and thus would likely help slghtly more as far as stability in the landing roll is concerned. Things that normally blow tires are almost nonexistant in the environment that a spacecraft would be operational in, however (FOD heavy wear from repeated cycles -(because new tires are cheap) and so on).

Was this part of the reasoning why they went for a skid in that position rather than a wheel, or is there more to it than that?
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Rocket Science on 07/13/2012 10:49 pm
Mounts soapbox…

Well we’re hearing talk of Dream Chaser might not make the cut. So why don't they offer the service/vehicle to ESA? DC is launch vehicle agnostic so why not Ariane V or Soyuz. This bird deserves to fly, if the powers that be in the U.S. don’t appreciate it then offer it up internationally. She has waited 20 plus years from her first iteration, long enough I think…

Steps off…

Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Lee Jay on 07/13/2012 11:25 pm
I'm delighted to see that Dream Chaser is making progress; at least there's a spaceplane successor to the Shuttles as well as the new capsules.

I do have a few minor reservations about Dream Chaser's skid strip nose gear though; how does a pilot steer Dream Chaser after touchdown, for example to compensate for a crosswind or a flat tyre on the main gear?

I'm not sure what material the skid strip would be made from, but wouldn't a solid piece of whatever material is used suffer too much friction scraping against the runway and possibly be damaged? Will the skid strip be replaced after every landing like the Shuttle Orbiter's tyres or not?

Also, how would Dream Chaser be moved to the hangar/OPF after landing; would it be towed like the Shuttle Orbiter, but with the skid strip scraping on the ground, towed on its main gear only with the skid strip raised off the ground somehow, or loaded onto a wheeled transporter similar to the one used to roll the Shuttle Orbiters over to the VAB for stacking?

 ???
Differential braking and a nose gear dolly...

And the aero surfaces while it's still at high enough speed.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Rocket Science on 07/13/2012 11:32 pm
Mounts soapbox…

Well we’re hearing talk of Dream Chaser might not make the cut. So why do they offer the service to ESA?

Not sure you phrased that second sentence the way you meant to do.

Quote
DC is launch vehicle agnostic so why not Ariane V or Soyuz. This bird deserves to fly, if the powers that be in the U.S. don’t appreciate it then offer it up internationally. She has waited 20 plus years from her first iteration, long enough I think…

ITAR.
Hey Jorge,

What I'm thinking is along the lines that we had with the X-38/CRV and ESA if it had come to be. If that was flying today how would ITAR affect it?

~Robert
(Thanks Jorge fixed that, little frustrated I guess...)

http://www.spaceref.com/news/viewnews.html?id=353
http://www.esa.int/esaHS/ESARZS0VMOC_iss_0.html
http://www.theconquestofspace.com/2011/03/saga-of-x-38.html
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Prober on 07/14/2012 12:17 am
Mounts soapbox…

Well we’re hearing talk of Dream Chaser might not make the cut. So why don't they offer the service/vehicle to ESA?


We are?   goes to double check L2
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Rocket Science on 07/14/2012 12:24 am
Mounts soapbox…

Well we’re hearing talk of Dream Chaser might not make the cut. So why don't they offer the service/vehicle to ESA?


We are?   goes to double check L2
Saw some talk on other threads today...
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: zerm on 07/14/2012 01:49 am
The skid does about the same for a pilot as any nosewheel in the initial portion of the landing of a high performance aircraft- i.e. stay straight and don't shimmy. That is all you want it to do- period.

So far a a cross wind, the best way to handle it is to simply avoid it as much as you can. in other words do not crab well (see Milt Thompson's "Flying Without Wings" and Dale Reed's "Wingless Flight"). Thus, in short, you select landing times and sites where the crosswind is a very low factor.

So far as a "blown tire" you do what any pilot would do- hope not. No matter if you had a skid or a nosewheel, in the case of a blown main, it would make very little differance in the outcome IMO. In fact the skid would likely have greater surface to runway friction and thus would likely help slghtly more as far as stability in the landing roll is concerned. Things that normally blow tires are almost nonexistant in the environment that a spacecraft would be operational in, however (FOD heavy wear from repeated cycles -(because new tires are cheap) and so on).

Was this part of the reasoning why they went for a skid in that position rather than a wheel, or is there more to it than that?

Could not say what their reasoning is- all I'm saying is that under the circumstances in question, the skid is just as effictive.

Also; Keep in mind that most "blown tires" that I've seen (as both a pilot and a mechanic) were caused by FOD picked up on the takeoff roll and not the landing roll. The exceptions being emergency landings, locked brakes, anti-skid malfunctions combined with unusually heavy braking and so on. Tires used on vehicles such as DC are not what most people would consider to be "tires" such as those you use on your car or even on an airliner. I'm sure they will be engineered to easily be able to take the stress on the very few landings that each will be subjected to. The skid will be just fine IMO.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Rocket Science on 07/14/2012 10:17 am
Mounts soapbox…

Well we’re hearing talk of Dream Chaser might not make the cut. So why do they offer the service to ESA?

Not sure you phrased that second sentence the way you meant to do.

Quote
DC is launch vehicle agnostic so why not Ariane V or Soyuz. This bird deserves to fly, if the powers that be in the U.S. don’t appreciate it then offer it up internationally. She has waited 20 plus years from her first iteration, long enough I think…

ITAR.
Hey Jorge,

What I'm thinking is along the lines that we had with the X-38/CRV and ESA if it had come to be. If that was flying today how would ITAR affect it?

~Robert
(Thanks Jorge fixed that, little frustrated I guess...)

http://www.spaceref.com/news/viewnews.html?id=353
http://www.esa.int/esaHS/ESARZS0VMOC_iss_0.html
http://www.theconquestofspace.com/2011/03/saga-of-x-38.html

A couple of things I observed as ITAR was implemented at NASA:

1) Although the relevant laws were passed in the late 1990s, the law required the State Department to write a bunch of regulations to actually implement it. This "trickled down" to NASA over the following decade. The effects this would have had on any plans to fly X-38/CRV on Ariane did not become evident prior to X-38 cancellation.

2) The law treats transfers by private companies markedly differently than transfers by the US government itself.

#2 manifested itself in the ISS program in some pretty perverse ways, such as contractor employees not being allowed to make certain presentations when ISS international partners were in the room, but if the presentation were handed to a NASA civil servant and he presented it, that was no problem. And that was indeed the short-term workaround, followed by a mid-term workaround of actually rebadging some contractors as civil servants, and a long-term solution of NASA obtaining a "generic" export license allowing contractors to interact with ISS IPs.

(The very fact that NASA was willing to consider hiring away contractor personnel as the *mid* term solution should be a clue as to just how much of a pain in the ass it was for NASA to get that generic license.)

So my take on it is that flying X-38 on Ariane, had it survived, would have had to deal with a period of awkward transition to deal with ITAR, much like the ISS program did. And second, that Sierra Nevada would have a considerably tougher time getting the required export licenses than the ISS program did. They would need to do their own cost-benefit analysis to determine if it's worthwhile for them.
Thank you Jorge for the very insightful answers.  :) I can appreciate the need for arms controls especially what has happened in the past, but the very fact that we export fighter planes and other weapons systems to our allies even today is interesting (many of them are ISS partners). Also as you know ILS also flys U.S. spacecraft on foreign launchers as well on a regular basis.
 
If thing do go badly for SNC in this competition at least they may have an option with this route. I know ESA got burned with the X-38/CRV project and may be a bit gun shy to repeat it again. Perhaps JAXA might be interested as well on their launchers.
 
So it might be challenging for this to happen, but not impossible for the ISS partners to have greater autonomy as they have wished for in the past with their own vehicle.

As always it is going to boil down to time and money to pursue it like you said.

Regards
Robert
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Jim on 07/14/2012 12:27 pm

Thank you Jorge for the very insightful answers.  :) I can appreciate the need for arms controls especially what has happened in the past, but the very fact that we export fighter planes and other weapons systems to our allies even today is interesting (many of them are ISS partners). Also as you know ILS also flys U.S. spacecraft on foreign launchers as well on a regular basis.
 
If thing do go badly for SNC in this competition at least they may have an option with this route. I know ESA got burned with the X-38/CRV project and may be a bit gun shy to repeat it again. Perhaps JAXA might be interested as well on their launchers.
 
So it might be challenging for this to happen, but not impossible for the ISS partners to have greater autonomy as they have wished for in the past with their own vehicle.


Not true.  Fighters are not launch vehicles and aren't controlled the same way.  Same goes for integrating spacecraft onto launch vehicles, not the same thing as giving them the hardware.

No, SNC doesn't really have the options as you describe.

They only can sell rides and not the vehicle
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Rocket Science on 07/14/2012 12:55 pm

Thank you Jorge for the very insightful answers.  :) I can appreciate the need for arms controls especially what has happened in the past, but the very fact that we export fighter planes and other weapons systems to our allies even today is interesting (many of them are ISS partners). Also as you know ILS also flys U.S. spacecraft on foreign launchers as well on a regular basis.
 
If thing do go badly for SNC in this competition at least they may have an option with this route. I know ESA got burned with the X-38/CRV project and may be a bit gun shy to repeat it again. Perhaps JAXA might be interested as well on their launchers.
 
So it might be challenging for this to happen, but not impossible for the ISS partners to have greater autonomy as they have wished for in the past with their own vehicle.


Not true.  Fighters are not launch vehicles and aren't controlled the same way.  Same goes for integrating spacecraft onto launch vehicles, not the same thing as giving them the hardware.

No, SNC doesn't really have the options as you describe.

They only can sell rides and not the vehicle
Fair enough Jim. They still are sensitive technologies. I guess we'll have to see it play out...

Regards
Robert
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Soaring Habu on 07/15/2012 05:19 pm
The skid does about the same for a pilot as any nosewheel in the initial portion of the landing of a high performance aircraft- i.e. stay straight and don't shimmy. That is all you want it to do- period.

So far a a cross wind, the best way to handle it is to simply avoid it as much as you can. in other words do not crab well (see Milt Thompson's "Flying Without Wings" and Dale Reed's "Wingless Flight"). Thus, in short, you select landing times and sites where the crosswind is a very low factor.

So far as a "blown tire" you do what any pilot would do- hope not. No matter if you had a skid or a nosewheel, in the case of a blown main, it would make very little differance in the outcome IMO. In fact the skid would likely have greater surface to runway friction and thus would likely help slghtly more as far as stability in the landing roll is concerned. Things that normally blow tires are almost nonexistant in the environment that a spacecraft would be operational in, however (FOD heavy wear from repeated cycles -(because new tires are cheap) and so on).

I'm used to thinking in terms of the Shuttle Orbiter with its wheeled nose gear, and how the Orbiter originally used Edwards AFB as its primary landing site because of the extra room there in case of steering problems after touchdown; later, after the Orbiter was fitted with fully functional nosewheel and improved brakes, the SLF at KSC became the primary landing site.

I know that Dream Chaser is much smaller and lighter than the Orbiter; so even if the skid is safer than a wheeled nose gear for Dream Chaser, I suspect that it wouldn't have worked on the Orbiter, because of the Orbiter's extra size and weight.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Star One on 07/16/2012 01:24 pm
The skid does about the same for a pilot as any nosewheel in the initial portion of the landing of a high performance aircraft- i.e. stay straight and don't shimmy. That is all you want it to do- period.

So far a a cross wind, the best way to handle it is to simply avoid it as much as you can. in other words do not crab well (see Milt Thompson's "Flying Without Wings" and Dale Reed's "Wingless Flight"). Thus, in short, you select landing times and sites where the crosswind is a very low factor.

So far as a "blown tire" you do what any pilot would do- hope not. No matter if you had a skid or a nosewheel, in the case of a blown main, it would make very little differance in the outcome IMO. In fact the skid would likely have greater surface to runway friction and thus would likely help slghtly more as far as stability in the landing roll is concerned. Things that normally blow tires are almost nonexistant in the environment that a spacecraft would be operational in, however (FOD heavy wear from repeated cycles -(because new tires are cheap) and so on).

Was this part of the reasoning why they went for a skid in that position rather than a wheel, or is there more to it than that?

Could not say what their reasoning is- all I'm saying is that under the circumstances in question, the skid is just as effictive.

Also; Keep in mind that most "blown tires" that I've seen (as both a pilot and a mechanic) were caused by FOD picked up on the takeoff roll and not the landing roll. The exceptions being emergency landings, locked brakes, anti-skid malfunctions combined with unusually heavy braking and so on. Tires used on vehicles such as DC are not what most people would consider to be "tires" such as those you use on your car or even on an airliner. I'm sure they will be engineered to easily be able to take the stress on the very few landings that each will be subjected to. The skid will be just fine IMO.

Thanks for that just interested me as to why they had gone that route, but it sounds like in the circumstances either is as good as the other.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Lobo on 07/16/2012 04:44 pm

Thank you Jorge for the very insightful answers.  :) I can appreciate the need for arms controls especially what has happened in the past, but the very fact that we export fighter planes and other weapons systems to our allies even today is interesting (many of them are ISS partners). Also as you know ILS also flys U.S. spacecraft on foreign launchers as well on a regular basis.
 
If thing do go badly for SNC in this competition at least they may have an option with this route. I know ESA got burned with the X-38/CRV project and may be a bit gun shy to repeat it again. Perhaps JAXA might be interested as well on their launchers.
 
So it might be challenging for this to happen, but not impossible for the ISS partners to have greater autonomy as they have wished for in the past with their own vehicle.


Not true.  Fighters are not launch vehicles and aren't controlled the same way.  Same goes for integrating spacecraft onto launch vehicles, not the same thing as giving them the hardware.

No, SNC doesn't really have the options as you describe.

They only can sell rides and not the vehicle
Fair enough Jim. They still are sensitive technologies. I guess we'll have to see it play out...

Regards
Robert

So if I understand correctly, they could sell rides to ESA or JAXA, although it might be pretty expensive per seat if those seats are funding the entire launch, as well as the final development of Dreamchaser (if they were to be down selected). 

Additionally, I think ESA and JAXA have been getting rides from NASA as part of their contributions to the ISS, before the Shuttle was retired.  Once NASA has two or 2.5 commercial carriers funded and flying, wouldn’t that partnership agreement continue?  Aren’t the JAXA and ESA modules, along with HTV and ATV serives sort of in return for crew services by NASA?  I’m not sure how all of that works, but just saying that once NASA has commercial crew providers selected and flying, JAXA and ESA will probably get cheaper seats on those than by contracting their own crew launch provider in SNC.  Especially since DC sounds like it couldn’t be sold to them to launch on their own LV’s.  It’d have to launch from Canaveral on Atlas V.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Star One on 07/16/2012 06:52 pm
Would it possible to drop launch the DC from an aircraft at some point down the line?
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Rocket Science on 07/16/2012 09:46 pm
Would it possible to drop launch the DC from an aircraft at some point down the line?
You would need something along the lines of Stratolaunch plus booster stages...
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: BrightLight on 07/16/2012 10:44 pm
Would it possible to drop launch the DC from an aircraft at some point down the line?
You would need something along the lines of Stratolaunch plus booster stages...
So, would Stratolaunch et al., be more cost effective then Atlas V?
Which one is safer?
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Rocket Science on 07/16/2012 10:50 pm
Would it possible to drop launch the DC from an aircraft at some point down the line?
You would need something along the lines of Stratolaunch plus booster stages...
So, would Stratolaunch et al., be more cost effective then Atlas V?
Which one is safer?
There is only one choice at this time for both safety and cost between the two, Atlas V…

“Actuality always trumps potentiality”… ;)
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Helodriver on 07/16/2012 11:11 pm
If the nose skid actuator were built in such a way to provide extension and retraction forces, the skid would make a very effective speedbrake for control of descent rate and approach speed once in aerodynamic flight.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Star One on 07/17/2012 01:28 pm
Would it possible to drop launch the DC from an aircraft at some point down the line?
You would need something along the lines of Stratolaunch plus booster stages...

Thanks. I thought I had read there was some kind of plan to launch it from a future version of the White Knight.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Rocket Science on 07/17/2012 01:34 pm
Would it possible to drop launch the DC from an aircraft at some point down the line?
You would need something along the lines of Stratolaunch plus booster stages...

Thanks. I thought I had read there was some kind of plan to launch it from a future version of the White Knight.
Yes, you are correct for the test flight phase, but on the current WK2... :)
http://www.parabolicarc.com/2012/02/13/cool-images-sierra-nevadas-dream-chaser/
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: zerm on 07/20/2012 06:11 pm
If the nose skid actuator were built in such a way to provide extension and retraction forces, the skid would make a very effective speedbrake for control of descent rate and approach speed once in aerodynamic flight.


Such equipment would probably cause an un-needed weight penalty as well as an un-needed addition of a series of systems/ sub-systems that could fail. Simple and lightweight is better.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Rocket Science on 07/20/2012 06:41 pm
If the nose skid actuator were built in such a way to provide extension and retraction forces, the skid would make a very effective speedbrake for control of descent rate and approach speed once in aerodynamic flight.


Such equipment would probably cause an un-needed weight penalty as well as an un-needed addition of a series of systems/ sub-systems that could fail. Simple and lightweight is better.
I agree with you Wes. The HL-20 was tested with vaious combinations of control sufaces to act also as speed brakes. We may yet see something like a split rudder in it's final configuation....

~Robert
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: BrightLight on 07/27/2012 03:00 pm
screen capture from video (around 49:35) dated 7/26/12 shows the crew access tower at LC-41 for either CST-100 or DC.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Orbiter on 07/28/2012 11:56 pm
Out of curiosity, does SNC plan on Dream Chaser to utilize TAL abort sites in the unlikely event they are necessary? Haven't heard it addressed.

Orbiter
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Rocket Science on 07/29/2012 01:03 am
Out of curiosity, does SNC plan on Dream Chaser to utilize TAL abort sites in the unlikely event they are necessary? Haven't heard it addressed.

Orbiter
Any city airport with a 7000' runway should suffice for any landing...
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Orbiter on 07/29/2012 01:20 am
Out of curiosity, does SNC plan on Dream Chaser to utilize TAL abort sites in the unlikely event they are necessary? Haven't heard it addressed.

Orbiter
Any city airport with a 7000' runway should suffice for any landing...

True, but they really can't land it anywhere they please overseas without permission. Maybe I should rephrase as will Dream Chaser use TAL or will they just ditch it in the event of a failure going uphill?

Orbiter
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: zt on 07/29/2012 01:27 am
How can the Dream Chaser be transported back to the launch/processing site after landing at some random airport? It can't take off on it own, it doesn't fit on a truck (is that right?), and AFAIK it doesn't have a special transporter plane and mounting harness.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Rocket Science on 07/29/2012 01:28 am
Out of curiosity, does SNC plan on Dream Chaser to utilize TAL abort sites in the unlikely event they are necessary? Haven't heard it addressed.

Orbiter
Any city airport with a 7000' runway should suffice for any landing...

True, but they really can't land it anywhere they please overseas without permission. Maybe I should rephrase as will Dream Chaser use TAL or will they just ditch it in the event of a failure going uphill?

Orbiter
I say this as a pilot. If the declare a "mayday", permissision will be granted to land in any friendly nation. The TAL sites are still there but it will not need all the support crew convoy like Shuttle did the "safe" the vehicle.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Rocket Science on 07/29/2012 01:28 am
How can the Dream Chaser be transported back to the launch/processing site after landing at some random airport? It can't take off on it own, it doesn't fit on a truck (is that right?), and AFAIK it doesn't have a special transporter plane and mounting harness.
WK2
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Jason1701 on 07/29/2012 01:34 am
How can the Dream Chaser be transported back to the launch/processing site after landing at some random airport? It can't take off on it own, it doesn't fit on a truck (is that right?), and AFAIK it doesn't have a special transporter plane and mounting harness.
WK2

That would likely require a special agreement with Virgin, as all WK2s should be in regular use by the time DC flies. I wonder if one will be forthcoming.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Rocket Science on 07/29/2012 01:36 am
How can the Dream Chaser be transported back to the launch/processing site after landing at some random airport? It can't take off on it own, it doesn't fit on a truck (is that right?), and AFAIK it doesn't have a special transporter plane and mounting harness.
WK2

That would likely require a special agreement with Virgin, as all WK2s should be in regular use by the time DC flies. I wonder if one will be forthcoming.
Skycrane then...
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: manboy on 07/29/2012 01:39 am
Out of curiosity, does SNC plan on Dream Chaser to utilize TAL abort sites in the unlikely event they are necessary? Haven't heard it addressed.

Orbiter
Any city airport with a 7000' runway should suffice for any landing...

True, but they really can't land it anywhere they please overseas without permission. Maybe I should rephrase as will Dream Chaser use TAL or will they just ditch it in the event of a failure going uphill?

Orbiter
Most likely the former.

How can the Dream Chaser be transported back to the launch/processing site after landing at some random airport? It can't take off on it own, it doesn't fit on a truck (is that right?), and AFAIK it doesn't have a special transporter plane and mounting harness.
I'm guessing by boat.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: manboy on 07/29/2012 01:45 am
How can the Dream Chaser be transported back to the launch/processing site after landing at some random airport? It can't take off on it own, it doesn't fit on a truck (is that right?), and AFAIK it doesn't have a special transporter plane and mounting harness.
WK2

That would likely require a special agreement with Virgin, as all WK2s should be in regular use by the time DC flies. I wonder if one will be forthcoming.
Skycrane then...
Skycrane doesn't have the range to transport it across the Atlantic.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Rocket Science on 07/29/2012 01:47 am
How can the Dream Chaser be transported back to the launch/processing site after landing at some random airport? It can't take off on it own, it doesn't fit on a truck (is that right?), and AFAIK it doesn't have a special transporter plane and mounting harness.
WK2

That would likely require a special agreement with Virgin, as all WK2s should be in regular use by the time DC flies. I wonder if one will be forthcoming.
Skycrane then...
Skycrane doesn't have the range to transport it across the Atlantic.
Once again WK2...
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Downix on 07/29/2012 02:18 am
How can the Dream Chaser be transported back to the launch/processing site after landing at some random airport? It can't take off on it own, it doesn't fit on a truck (is that right?), and AFAIK it doesn't have a special transporter plane and mounting harness.
WK2

That would likely require a special agreement with Virgin, as all WK2s should be in regular use by the time DC flies. I wonder if one will be forthcoming.
Skycrane then...
Skycrane doesn't have the range to transport it across the Atlantic.
Once again WK2...
A stock 747 cargo plane could carry it.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: manboy on 07/29/2012 02:32 am
How can the Dream Chaser be transported back to the launch/processing site after landing at some random airport? It can't take off on it own, it doesn't fit on a truck (is that right?), and AFAIK it doesn't have a special transporter plane and mounting harness.
WK2

That would likely require a special agreement with Virgin, as all WK2s should be in regular use by the time DC flies. I wonder if one will be forthcoming.
Skycrane then...
Skycrane doesn't have the range to transport it across the Atlantic.
Once again WK2...
I'm not sure if it can either.

How can the Dream Chaser be transported back to the launch/processing site after landing at some random airport? It can't take off on it own, it doesn't fit on a truck (is that right?), and AFAIK it doesn't have a special transporter plane and mounting harness.
WK2

That would likely require a special agreement with Virgin, as all WK2s should be in regular use by the time DC flies. I wonder if one will be forthcoming.
Skycrane then...
Skycrane doesn't have the range to transport it across the Atlantic.
Once again WK2...
A stock 747 cargo plane could carry it.
That might be overkill.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: BrightLight on 07/29/2012 02:32 am
How can the Dream Chaser be transported back to the launch/processing site after landing at some random airport? It can't take off on it own, it doesn't fit on a truck (is that right?), and AFAIK it doesn't have a special transporter plane and mounting harness.
WK2

That would likely require a special agreement with Virgin, as all WK2s should be in regular use by the time DC flies. I wonder if one will be forthcoming.
Skycrane then...
Skycrane doesn't have the range to transport it across the Atlantic.
Once again WK2...
A stock 747 cargo plane could carry it.
I don't know if this is possible, but if the wing/fins can be removed after flight the body should fit into many cargo aircraft.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Downix on 07/29/2012 02:46 am
How can the Dream Chaser be transported back to the launch/processing site after landing at some random airport? It can't take off on it own, it doesn't fit on a truck (is that right?), and AFAIK it doesn't have a special transporter plane and mounting harness.
WK2

That would likely require a special agreement with Virgin, as all WK2s should be in regular use by the time DC flies. I wonder if one will be forthcoming.
Skycrane then...
Skycrane doesn't have the range to transport it across the Atlantic.
Once again WK2...
A stock 747 cargo plane could carry it.
I don't know if this is possible, but if the wing/fins can be removed after flight the body should fit into many cargo aircraft.
There's also the SuperGuppy and Antonov An-124.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: BrightLight on 07/29/2012 02:50 am
How can the Dream Chaser be transported back to the launch/processing site after landing at some random airport? It can't take off on it own, it doesn't fit on a truck (is that right?), and AFAIK it doesn't have a special transporter plane and mounting harness.
WK2

That would likely require a special agreement with Virgin, as all WK2s should be in regular use by the time DC flies. I wonder if one will be forthcoming.
Skycrane then...
Skycrane doesn't have the range to transport it across the Atlantic.
Once again WK2...
A stock 747 cargo plane could carry it.
I don't know if this is possible, but if the wing/fins can be removed after flight the body should fit into many cargo aircraft.
There's also the SuperGuppy and Antonov An-124.
yes, I forgot about the Anatov 124, yes it can do it, although it is not a cheap plane to rent, who runs the supper guppy, is it NASA?
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Jim on 07/29/2012 02:53 am
Guppy can't cross oceans and the 124 isn't that expensive.  It is a frequent visitor to the Cape.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Downix on 07/29/2012 03:06 am
Guppy can't cross oceans and the 124 isn't that expensive.  It is a frequent visitor to the Cape.
Since when can't the Guppy cross oceans? Did it suddenly lose range since the 1990's when it was flown from France to Florida?

Checking, unloaded, it's range is 3,211km, plenty to reach europe from the US. The cape to bangor. Bangor to iceland. Iceland to france. France to wherever the DC landed.  Once loaded, would need two more stops, but still easily done.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: adrianwyard on 07/29/2012 03:18 am
The Antonov is not wide enough to carry it without removing the tip fins. The Super Guppy is wide enough, however.

http://jsc-aircraft-ops.jsc.nasa.gov/guppy/index.html
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: adrianwyard on 07/29/2012 03:52 am
To head back briefly to the topic of nose-skid vs conventional landing gear:

A skid design might allow them to get the nose on the runway while the vehicle is still pitched up substantially, and the body is generating lift. This could be done with a very long nose gear strut too, but I bet a long skid is better solution for several reasons:

Simpler, lighter, more robust (for a given weight), takes less internal volume (it's essentially a nose gear door with no nose gear.)

Additionally, judging from the image it's probably generating a little lift of its own. The HL-20 experimented with the addition of canards at the front to add lift, lower landing speed, and improve landing characteristics (Rocket Science looked at this too). Even the Shuttle Orbiter with its large wings would come down heavily on the nose gear (especially before the addition of the tail parachute), so this probably was a potential problem for Dream Chaser too, and the long skid that keeps the nose up sounds like a good solution.

The image below is from the following video (starts at 17:00)

http://www.youtube.com/watch?v=6q3hHvdEqYE

Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Jim on 07/29/2012 04:28 am
Guppy can't cross oceans and the 124 isn't that expensive.  It is a frequent visitor to the Cape.
Since when can't the Guppy cross oceans? Did it suddenly lose range since the 1990's when it was flown from France to Florida?

Checking, unloaded, it's range is 3,211km, plenty to reach europe from the US. The cape to bangor. Bangor to iceland. Iceland to france. France to wherever the DC landed.  Once loaded, would need two more stops, but still easily done.

Your scenario is not possible, the range is much less with a load. 
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Downix on 07/29/2012 04:29 am
Guppy can't cross oceans and the 124 isn't that expensive.  It is a frequent visitor to the Cape.
Since when can't the Guppy cross oceans? Did it suddenly lose range since the 1990's when it was flown from France to Florida?

Which Guppy?
N941NA, the only one flying. While loaded to maximum, it's range is limited to 950 km, empty it's range is over 3200km, more then sufficient for the job. The SuperGuppy can lift over 24 metric tons. The DreamChaser is under 11 metric tons, which means that they will not be near capacity so would retain a good range.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Jim on 07/29/2012 04:32 am
Guppy can't cross oceans and the 124 isn't that expensive.  It is a frequent visitor to the Cape.
Since when can't the Guppy cross oceans? Did it suddenly lose range since the 1990's when it was flown from France to Florida?

Which Guppy?
N941NA, the only one flying. While loaded to maximum, it's range is limited to 950 km, empty it's range is over 3200km, more then sufficient for the job. The SuperGuppy can lift over 24 metric tons. The DreamChaser is under 11 metric tons, which means that they will not be near capacity so would retain a good range.

The DC will require a pallet with tie downs and hence the mass will make the range and scenario unworkable. 
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Downix on 07/29/2012 04:43 am
Guppy can't cross oceans and the 124 isn't that expensive.  It is a frequent visitor to the Cape.
Since when can't the Guppy cross oceans? Did it suddenly lose range since the 1990's when it was flown from France to Florida?

Which Guppy?
N941NA, the only one flying. While loaded to maximum, it's range is limited to 950 km, empty it's range is over 3200km, more then sufficient for the job. The SuperGuppy can lift over 24 metric tons. The DreamChaser is under 11 metric tons, which means that they will not be near capacity so would retain a good range.

The DC will require a pallet with tie downs and hence the mass will make the range and scenario unworkable. 
You feel that the DC will need 12 metric tons of pallet and tie downs?
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Jim on 07/29/2012 11:43 am

You feel that the DC will need 12 metric tons of pallet and tie downs?

no, just enough to make the range unusable for any trans Atlantic recovery.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Rocket Science on 07/29/2012 12:25 pm
I went to bed and missed all the fun! I really don’t anticipate aborts on a regular basis flying on such a reliable launcher the Atlas-Centaur. I don’t have any potential loss of mission numbers. Any event is going to be a rare occasion IMHO. In the event of an abort, I already mentioned the SkyCrane, WK2, and I will add the Airbus Beluga (about 2 feet to spare) to the mix.
I still feel the WK2 should suffice with stops such as you would do with a single engine trans-Atlantic flight as necessary… All this before my morning coffee, so bear this in mind…  ;D

http://www.tmoser.ch/typo3/19.0.html
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: BrightLight on 07/30/2012 12:22 am
A new (?) youtube video of the DC CONOPS
clearly shows the crew access tower and the latest drawings of the vehicle.

http://www.youtube.com/watch?v=rcrYurGgs_0
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Prober on 07/30/2012 03:25 am
A new (?) youtube video of the DC CONOPS
clearly shows the crew access tower and the latest drawings of the vehicle.


real good, looks like DC is offering cargo services like Liberty.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Lee Jay on 07/30/2012 03:31 am
How can the Dream Chaser be transported back to the launch/processing site after landing at some random airport?

Any number of ways, including truck or ship in addition to the large cargo aircraft mentioned above.  It's not that big and shipping stuff that size all over the world is an every-day occurrence in many industries.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: arkaska on 08/05/2012 07:27 am
Sorry if this have been discussed before but there are to many pages to go through to see if it have been discussed before.

Since DC will stay docked to the ISS for ~6 months its heat-shield will be exposed to MMOD strikes. Is this a concern for NASA? When the shuttle was docked ISS was flying 'backwards' to offer some protection to the shuttles heat-shield but this won't be possible for DC and it will be in front of the ISS and therefore fully exposed to MMOD strikes.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: A_M_Swallow on 08/05/2012 11:17 am
Sorry if this have been discussed before but there are to many pages to go through to see if it have been discussed before.

Since DC will stay docked to the ISS for ~6 months its heat-shield will be exposed to MMOD strikes. Is this a concern for NASA? When the shuttle was docked ISS was flying 'backwards' to offer some protection to the shuttles heat-shield but this won't be possible for DC and it will be in front of the ISS and therefore fully exposed to MMOD strikes.

Would a bullet proof shield, possible made out of Kevlar, placeable by the robotic arm be useful?
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: clongton on 08/05/2012 11:52 am
Sorry if this have been discussed before but there are to many pages to go through to see if it have been discussed before.

Easy solution: View the entire thread in printable format, then "print" it to a .pdf file. That gives you the ability to search the entire file, which "could" be a couple hundred pages (this one os only 5 pages), for key words. That would take you directly to the the posted comments relevant to what you want to know. It's a shame to not read them all though; one misses *so* much when they skip the reading.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Calphor on 08/05/2012 05:09 pm
Sorry if this have been discussed before but there are to many pages to go through to see if it have been discussed before.

Since DC will stay docked to the ISS for ~6 months its heat-shield will be exposed to MMOD strikes. Is this a concern for NASA? When the shuttle was docked ISS was flying 'backwards' to offer some protection to the shuttles heat-shield but this won't be possible for DC and it will be in front of the ISS and therefore fully exposed to MMOD strikes.

Would a bullet proof shield, possible made out of Kevlar, placeable by the robotic arm be useful?

It would need to be something more akin to a Whipple Shield than a straight Kevlar-type systems, but it could be feasible. Approach velocities are extreme (>3 km/s) and Whipple-type systems are much more mass efficient at those velocities. The only problem is that is one more large system to maintain and deploy on orbit.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Robotbeat on 08/05/2012 10:19 pm
Sorry if this have been discussed before but there are to many pages to go through to see if it have been discussed before.

Easy solution: View the entire thread in printable format, then "print" it to a .pdf file. That gives you the ability to search the entire file, which "could" be a couple hundred pages (this one os only 5 pages), for key words. That would take you directly to the the posted comments relevant to what you want to know. It's a shame to not read them all though; one misses *so* much when they skip the reading.
Don't need to actually print it to a PDF. When you click "print" in the forum, you can just use your browser's built-in search function (i.e. Ctrl-F).
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: vt_hokie on 08/07/2012 03:35 am
Aren't those aft thrusters exposed to some of the highest heating during reentry?
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Ronsmytheiii on 08/08/2012 01:45 am
Since DC will stay docked to the ISS for ~6 months its heat-shield will be exposed to MMOD strikes. Is this a concern for NASA? When the shuttle was docked ISS was flying 'backwards' to offer some protection to the shuttles heat-shield but this won't be possible for DC and it will be in front of the ISS and therefore fully exposed to MMOD strikes.

The X-37 flight lasted about a year each and were fine in regards to MMOD, I would be more concerned with the cabin windows than the heat shield as on PMA-2 DC will have a minimal cross section of the lower heat shield in the velocity bar.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Go4TLI on 08/08/2012 01:57 am
Since DC will stay docked to the ISS for ~6 months its heat-shield will be exposed to MMOD strikes. Is this a concern for NASA? When the shuttle was docked ISS was flying 'backwards' to offer some protection to the shuttles heat-shield but this won't be possible for DC and it will be in front of the ISS and therefore fully exposed to MMOD strikes.

The X-37 flight lasted about a year each and were fine in regards to MMOD, I would be more concerned with the cabin windows than the heat shield as on PMA-2 DC will have a minimal cross section of the lower heat shield in the velocity bar.

In addition all MMOD does not come in from the same vector.  There is also the OBSS still on ISS if one suspects something.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Robotbeat on 08/08/2012 07:44 pm
What's the angular distribution of MMOD?
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: yg1968 on 08/24/2012 02:36 pm
One thing I have been wondering about is what will happen to DC if it doesn't get chosen by NASA for the next round in 2014.

I believe that SNC has plans for DC outside of NASA. But I wonder what those plans are and if Richard Branson would be involved with them. A while ago, Branson had stated that he wanted to get involved in orbital crewed flights but so far that involvement has been fairly limited. I sort of wonder if he is waiting for the right moment to get more involved in DC.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: zt on 08/24/2012 03:25 pm
Richard Branson doesn't have the funds.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: yg1968 on 08/24/2012 04:25 pm
Richard Branson doesn't have the funds.

His net worth is $4.2B which is a lot more than Elon. But I don't think that he will get into a venture unless there is a reasonable expectation of profit from it.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: dcporter on 08/25/2012 01:02 am
His net worth is $4.2B which is a lot more than Elon. But I don't think that he will get into a venture unless there is a reasonable expectation of profit from it.

Elon only gets into things when success is an option, so, that's basically the same...
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: yg1968 on 08/25/2012 01:13 am
I agree. I just wonder if success is an option without a NASA contract.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: QuantumG on 08/25/2012 02:12 am
Elon only gets into things when success is an option, so, that's basically the same...

Which makes me wonder if you really want or need a government agency to "get into things" when success isn't an option.

What's this got to do with SNC again?
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: yg1968 on 08/25/2012 02:54 am
He was responding to my post about Richard Branson and DC.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: docmordrid on 08/25/2012 07:39 am
If Branson could design a business plan with Tier 1 suborbital flights on SS2 and the advanced Tier 2 orbital flights on DC for both joyriders an serious experimenters (including universities) then NASA funding isn't a concern.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: zerm on 08/25/2012 04:09 pm
Reading the posts about landing at any airport with a 7,000+ foot runway got me wondering. Very few airporths support glideslopes greater than 3 degrees, DC will likely fly a 19 to 23 degree approach. I'm wondering if that can be electronically compensated with by way of a GPS glideslope. Any avionics heads out there who would like to chime in on this?
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: clongton on 08/25/2012 07:58 pm
Reading the posts about landing at any airport with a 7,000+ foot runway got me wondering. Very few airporths support glideslopes greater than 3 degrees, DC will likely fly a 19 to 23 degree approach. I'm wondering if that can be electronically compensated with by way of a GPS glideslope. Any avionics heads out there who would like to chime in on this?

Any idea how many airports with 7,000 foot runways there are that would fall under DC cross range limits?
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Rocket Science on 08/30/2012 03:45 pm
Reading the posts about landing at any airport with a 7,000+ foot runway got me wondering. Very few airporths support glideslopes greater than 3 degrees, DC will likely fly a 19 to 23 degree approach. I'm wondering if that can be electronically compensated with by way of a GPS glideslope. Any avionics heads out there who would like to chime in on this?

Any idea how many airports with 7,000 foot runways there are that would fall under DC cross range limits?
Here is a Global list for runway data Chuck, U.S. alone (2,438 to 3,047 m: 235 ) lots of choices. ;)

https://www.cia.gov/library/publications/the-world-factbook/fields/2030.html
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: clongton on 08/31/2012 01:33 am
Any idea how many airports with 7,000 foot runways there are that would fall under DC cross range limits?
Here is a Global list for runway data Chuck, U.S. alone (2,438 to 3,047 m: 235 ) lots of choices. ;)

https://www.cia.gov/library/publications/the-world-factbook/fields/2030.html

Thanks
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Comga on 08/31/2012 05:11 am
What's the angular distribution of MMOD?

Predominantly from behind and the sides.  Stuff coming in from the front is going slower, so has a lower perigee, so has experienced more atmospheric drag and is likely to be scrubbed out of orbit relatively quickly.  That's one reason the ISS orbit is not higher, I believe.

Ditto on things coming in from below.  They have seen more drag.  (However, there was a strike on the Cupola.)
Same altitude orbits in different inclinations approach from the sides.
Stuff in elliptical orbits with higher apogees comes in from behind.

The front of the ISS is probably a relatively safe place, particularly if the VV doesn't stick out like the Shuttle did.

Someone must have quantitative data.  Look online for orbital debris quarterly reports from NASA.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Robotbeat on 08/31/2012 02:27 pm
What's the angular distribution of MMOD?

Predominantly from behind and the sides.  Stuff coming in from the front is going slower, so has a lower perigee, so has experienced more atmospheric drag and is likely to be scrubbed out of orbit relatively quickly.  That's one reason the ISS orbit is not higher, I believe.

Ditto on things coming in from below.  They have seen more drag.  (However, there was a strike on the Cupola.)
Same altitude orbits in different inclinations approach from the sides.
Stuff in elliptical orbits with higher apogees comes in from behind.

The front of the ISS is probably a relatively safe place, particularly if the VV doesn't stick out like the Shuttle did.

Someone must have quantitative data.  Look online for orbital debris quarterly reports from NASA.
It'd be really nice to see a pretty graph of the angular distribution. My Googlefu isn't strong enough, this is all I've found so far:
http://www.sciencedirect.com/science/article/pii/S0032063301000423
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: zerm on 09/01/2012 03:32 pm
Runway length is only a small element in this. You can have a 15k Ft. runway waiting for you but if you do not have exact onboard, ground, and visual guidence to take you to the approach end of that runway- in the proper attitude and at the proper airspeed, the length does not mean squat. Thus, there may not be "plenty of choices."
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Rocket Science on 09/01/2012 04:03 pm
Runway length is only a small element in this. You can have a 15k Ft. runway waiting for you but if you do not have exact onboard, ground, and visual guidence to take you to the approach end of that runway- in the proper attitude and at the proper airspeed, the length does not mean squat. Thus, there may not be "plenty of choices."
Wes, pilot to pilot, I get what you are saying, but this is in an abort or emergency landing. Without knowing what avionics are on board we are pretty much “flying in the dark”, pun intended! ;D  On the other hand the series of X-Planes routinely made landings on dry lakebeds and runways pretty much with only the “sacred six” (plus Q- Ball in the case of the X-15) instruments plus radar data… Energy management is the real item for consideration for a successful landing and a variation of the Terminal Area Energy Management (TAEM) similar to Shuttle will more than likely be utilized…


Edit to add:
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: clongton on 09/01/2012 06:03 pm
For emergency landing situations all the pilot really needs, with today's avionics, is the gps coordinates of the runway, its altitude above sea level and the radio frequency of the tower. If he's got those he can land safely. It might be a rough ride  to the runway depending on current altitude, direction, rate of descent and airspeed, but a good pilot will know which ones he can make, which ones are iffy and which ones he can't, based on his current position. I can't imagine DC being launched without those 3 data nodes being loaded into the guidance avionics. If the guidance avionics can't compute a flight path to a known runway from current position, altitude, rate of descent and airspeed then throw it out and get another one that's been properly programmed. It's not that hard to compute.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: vulture4 on 09/02/2012 05:54 am
Runways of 3km or more are not common and busy commercial airports are loath to consent to be used for emergency landings of spacecraft. The entire world was surveyed repeatedly for runways for both Shuttle and CERV. The short answer is that they exist, but not in profusion. The Shuttle emergency landing sites around the world are well known; the majority are military fields that could be cleared quickly for an emergency landing. The approach cannot possibly be hand-flown, particularly with something like the DC which has very little aerodynamic reserve; everything from TIG to wheel stop must be autonomous. This was never possible with Shuttle, which predated even GPS. It had an autoland system but it was organizationally infeasible to even test it. In contrast the X-37 has so far made two completely autonomous landings with no significant problems.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Lurker Steve on 09/02/2012 02:06 pm
Runways of 3km or more are not common and busy commercial airports are loath to consent to be used for emergency landings of spacecraft. The entire world was surveyed repeatedly for runways for both Shuttle and CERV. The short answer is that they exist, but not in profusion. The Shuttle emergency landing sites around the world are well known; the majority are military fields that could be cleared quickly for an emergency landing. The approach cannot possibly be hand-flown, particularly with something like the DC which has very little aerodynamic reserve; everything from TIG to wheel stop must be autonomous. This was never possible with Shuttle, which predated even GPS. It had an autoland system but it was organizationally infeasible to even test it. In contrast the X-37 has so far made two completely autonomous landings with no significant problems.

I assume the problem is that any airport with a suitable runway, is that the airport likes to use them for landing airplanes. For instance, I assume you technically could land the DC at OHare, DFW, Atlanta, LAX, Denver, etc. But that would probably mean shutting down all aircraft operations for hours. And then, losing a major airport for hours means major air traffic delays that ripple across the entire system.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Lee Jay on 09/02/2012 02:57 pm
Runways of 3km or more are not common and busy commercial airports are loath to consent to be used for emergency landings of spacecraft. The entire world was surveyed repeatedly for runways for both Shuttle and CERV. The short answer is that they exist, but not in profusion. The Shuttle emergency landing sites around the world are well known; the majority are military fields that could be cleared quickly for an emergency landing. The approach cannot possibly be hand-flown, particularly with something like the DC which has very little aerodynamic reserve; everything from TIG to wheel stop must be autonomous. This was never possible with Shuttle, which predated even GPS. It had an autoland system but it was organizationally infeasible to even test it. In contrast the X-37 has so far made two completely autonomous landings with no significant problems.

I assume the problem is that any airport with a suitable runway, is that the airport likes to use them for landing airplanes. For instance, I assume you technically could land the DC at OHare, DFW, Atlanta, LAX, Denver, etc. But that would probably mean shutting down all aircraft operations for hours. And then, losing a major airport for hours means major air traffic delays that ripple across the entire system.

That's just entirely inaccurate.  Any time any aircraft declares an in-flight emergency, the airport in question can get clear and ready for them in seconds or tens of seconds.  This happens all the time right now without causing major ripples throughout the system.  Weather events cause a lot more havoc.  Second, even if DC did have to land quickly at some random airport, that would only close one runway for a short time, not the whole airport for a long time.  It's not a big craft, and it's non-toxic.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: clongton on 09/02/2012 03:14 pm
Runways of 3km or more are not common and busy commercial airports are loath to consent to be used for emergency landings of spacecraft. The entire world was surveyed repeatedly for runways for both Shuttle and CERV. The short answer is that they exist, but not in profusion. The Shuttle emergency landing sites around the world are well known; the majority are military fields that could be cleared quickly for an emergency landing. The approach cannot possibly be hand-flown, particularly with something like the DC which has very little aerodynamic reserve; everything from TIG to wheel stop must be autonomous. This was never possible with Shuttle, which predated even GPS. It had an autoland system but it was organizationally infeasible to even test it. In contrast the X-37 has so far made two completely autonomous landings with no significant problems.

I assume the problem is that any airport with a suitable runway, is that the airport likes to use them for landing airplanes. For instance, I assume you technically could land the DC at OHare, DFW, Atlanta, LAX, Denver, etc. But that would probably mean shutting down all aircraft operations for hours. And then, losing a major airport for hours means major air traffic delays that ripple across the entire system.

That's just entirely inaccurate.  Any time any aircraft declares an in-flight emergency, the airport in question can get clear and ready for them in seconds or tens of seconds.  This happens all the time right now without causing major ripples throughout the system.  Weather events cause a lot more havoc.  Second, even if DC did have to land quickly at some random airport, that would only close one runway for a short time, not the whole airport for a long time.  It's not a big craft, and it's non-toxic.

Thank you. I was about to post nearly exactly the same thing. All DC needs to know is where they are and where the runway is and their flight avionics will take it from there. Once notifying the tower that they are making an emergency landing the runway will be clear and ready for them when they get there. No airport will ever refuse an emergency landing to anybody, aircraft or spacecraft, once an emergency is declared.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Rocket Science on 09/02/2012 04:22 pm
Runways of 3km or more are not common and busy commercial airports are loath to consent to be used for emergency landings of spacecraft. The entire world was surveyed repeatedly for runways for both Shuttle and CERV. The short answer is that they exist, but not in profusion. The Shuttle emergency landing sites around the world are well known; the majority are military fields that could be cleared quickly for an emergency landing. The approach cannot possibly be hand-flown, particularly with something like the DC which has very little aerodynamic reserve; everything from TIG to wheel stop must be autonomous. This was never possible with Shuttle, which predated even GPS. It had an autoland system but it was organizationally infeasible to even test it. In contrast the X-37 has so far made two completely autonomous landings with no significant problems.

I assume the problem is that any airport with a suitable runway, is that the airport likes to use them for landing airplanes. For instance, I assume you technically could land the DC at OHare, DFW, Atlanta, LAX, Denver, etc. But that would probably mean shutting down all aircraft operations for hours. And then, losing a major airport for hours means major air traffic delays that ripple across the entire system.

That's just entirely inaccurate.  Any time any aircraft declares an in-flight emergency, the airport in question can get clear and ready for them in seconds or tens of seconds.  This happens all the time right now without causing major ripples throughout the system.  Weather events cause a lot more havoc.  Second, even if DC did have to land quickly at some random airport, that would only close one runway for a short time, not the whole airport for a long time.  It's not a big craft, and it's non-toxic.

Thank you. I was about to post nearly exactly the same thing. All DC needs to know is where they are and where the runway is and their flight avionics will take it from there. Once notifying the tower that they are making an emergency landing the runway will be clear and ready for them when they get there. No airport will ever refuse an emergency landing to anybody, aircraft or spacecraft, once an emergency is declared.
“In studying several off-nominal conditions, it was
discovered that the HL-20 design is quite robust and forgiving
on approach and consistent on landing. “

http://81.70.242.211/eab1/manual/Magazine/AIAA%20Journal%20of%20Aircraft/1994/3/Preliminary%20piloted%20simulation%20studies%20of%20the%20HL-20%20lifting%20body.pdf

When it comes to aborts or emergency priority landings, Vulture claims to be a pilot and if really true, should know better…
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: belegor on 09/02/2012 06:22 pm
That's just entirely inaccurate.  Any time any aircraft declares an in-flight emergency, the airport in question can get clear and ready for them in seconds or tens of seconds.  This happens all the time right now without causing major ripples throughout the system.  Weather events cause a lot more havoc.  Second, even if DC did have to land quickly at some random airport, that would only close one runway for a short time, not the whole airport for a long time.  It's not a big craft, and it's non-toxic.

That's actually not entirely true either: ICAO mandates the fire brigade to be at any point of the airport within two minutes, which means unless the respective airport has a fire brigade big enough to be able to respond to two emergencies simultaneously, the respective airport has to close down entirely, until the fire brigade is ready for a next potential emergency.

Therefore, even minor emergencies can easily cause delays of 20-30 minutes or even more, if the runway remains blocked for a longer time (and thus reducing the capacity of the airport).

Not that it really matters: I don't think airports really care whether it is a normal aircraft or a spacecraft making an emergency landing.. an emergency is an emergency...
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Lee Jay on 09/02/2012 06:51 pm
Not that it really matters: I don't think airports really care whether it is a normal aircraft or a spacecraft making an emergency landing.. an emergency is an emergency...

And there are tons of emergencies declared each year.  DC isn't likely to add to that by any significant amount compared to, say, bird strikes causing engine damage.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Robotbeat on 09/05/2012 04:09 pm
Not that it really matters: I don't think airports really care whether it is a normal aircraft or a spacecraft making an emergency landing.. an emergency is an emergency...

And there are tons of emergencies declared each year.  DC isn't likely to add to that by any significant amount compared to, say, bird strikes causing engine damage.
Except DreamChaser (or any orbital vehicle) is more likely to abort than an airliner is (proportional to number of flights per year per vehicle). This extra burden (more than usual) is borne by the airports. This is called an externality in economics.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: john smith 19 on 09/05/2012 07:29 pm
Except DreamChaser (or any orbital vehicle) is more likely to abort than an airliner is (proportional to number of flights per year per vehicle). This extra burden (more than usual) is borne by the airports. This is called an externality in economics.

This seems a fair point *except* that the only orbital vehicle we have seen (the space shuttle) *never* aborted in over 130 flights. It's failure modes were never that benign.

I don't think there's anyway to know if DC will be more "abort prone" than Shuttle. If flown it's LV has no SRB's to leak gases onto cryogenic tanks and it's location should avoid *any* debris from tank insulation shedding on the Atlas (does anyone know if Atlas *does* shed it's insulation?)  that leaves systems failures in the vehicle or on orbit damage.

DC's internal systems *seem* much simpler than Shuttle (well no lethally toxic propellants seem a good start) and it would present a smaller MMOD target so *should* be less likely to suffer surface damage to the TPS.

I've always wondered what happens if (billion billion to one chance I hope) the proverbial lost bolt hits the wind shield and goes through *all* the layers. 

However SNC *might* have to save money and go with lower redundancy or less experienced suppliers whose hardware is not *quite* as reliable as the NASA sourced equipment, leading to more aborts to emergency landing sites. NASA seemed especially worried about TPS damage and SNC having no repair material to fix it (although let's remember that STS flew *most* of its career without carrying such things).

IOW I think it's too finely balanced to call until it's built and operating. If the aerodynamic design is stable it *could* land with all its control surfaces locked in the last position they were powered at. This would downgrade *dozens* of failure types (in the computers, APUs an aerosurface drive system) from LOC or LOV to LOM. Nasty, expensive (if you can't get the landing gear down) but survivable.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Robotbeat on 09/05/2012 08:47 pm
...

I've always wondered what happens if (billion billion to one chance I hope) the proverbial lost bolt hits the wind shield and goes through *all* the layers. 
...
Well, you'd get decompression of the cabin, but (unless all the layers shattered) not instantly. The air would be rushing through the hole at a finite velocity, probably sonically choked. mass Flowrate would then be roughly:

mdot=areaofhole*speedofsound*densityofair*someconstantrelatingtoshapeofhole (we'll set the constant=1 for now, to get a rough order of magnitude estimate). Of course, the density of the air would decrease as air was lost.

mdot=-A*c*rho

total mass of air (as a function of time) = m
total volume (constant) of cabin = V
rho = m/V

mdot=-A*c*m/V

dm/dt=-(A*c/V)*m

for convenience, let's set (A*c/V)=w

dm/dt=-w*m

well, we have a differential equation on our hands! And a simple one, at that.

let's do some operations (this step always seemed bogus to me, but it's what you're supposed to do):

dm=-w*m*dt

get all the "m"s on the same side:

dm/m = -w*dt

now integrate both sides:

int((1/m)*dm)=int(-w*dt)+B
("B" is just some integration constant... we'll figure it out later)

which is just:

ln(m)=-w*t+B

To get m by itself:

e^ln(m)=e^(-w*t+B)

m = e^(-w*t)*e^B

yay! Now, we see that m=e^B at time=0, so let's replace e^B with m0:

m=m0*e^(-w*t)

to solve for when the air mass has dropped to a certain level, m1:

m1=m0*e^(-w*t)

t=-ln(m1/m0)/w

if we put the pressure at which consciousness is lost at 1.5 psi (comfortably above the Armstrong limit of ~.9psi), we get a m1/m0=.1
and thus:

for a 1cm^2 square hole (.01*.01m^2=.0001m^2) and Dreamchaser's volume of 16m^3:

t= -ln(.1)/(.0001m^2*343m/s/(16m^3)) = about 18 minutes.


so, barely enough time to do an extreme burn and get low enough in the atmosphere to keep the crew conscious, but not using usual reentry procedures. (If we put the limit at 4.6psi, about Everest pressure, it's just more than 8.5 minutes... probably not enough time.)

If that's not long enough, a small supply of air should be enough to keep the crew conscious for quite a while at 5psi. If you keep a few cabins' worth of air on board, you could do a half hour time between getting hit with the bolt and the crew losing consciousness. You could supply enough air for them to don space suits. Of course, the crew could also try plugging the hole to at least slow the leakrate.

So, air would be lost exponentially (until the pressure difference is low enough that it is no longer sonically choked... but that usually occurs only at very low pressures, which aren't survivable anyway).

If your hole is bigger than 1cm square, then you'll have less time, proportional to the area of the hole (or rather, your length of time would be inversely proportional to the area of the hole).


Is that a good answer?

(this is still just an approximation, but close enough)
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: baldusi on 09/05/2012 11:21 pm
Shuttle did aborted.. to orbit. But still an abort. The big question would be about a pad abort, for example. Or an abort and ditch.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: zerm on 09/17/2012 10:44 pm
Not that it really matters: I don't think airports really care whether it is a normal aircraft or a spacecraft making an emergency landing.. an emergency is an emergency...

And there are tons of emergencies declared each year.  DC isn't likely to add to that by any significant amount compared to, say, bird strikes causing engine damage.
Except DreamChaser (or any orbital vehicle) is more likely to abort than an airliner is (proportional to number of flights per year per vehicle). This extra burden (more than usual) is borne by the airports. This is called an externality in economics.

This is a good example of why space folks should stick to spaceflight and away from commercial aviation. I've done LOTS of aborts in airliners- yet the comparison is, as Jim would say, apples to oranges.

Frankly- this discussion is really going toward the what if monkeys may fly out of yer butt type of debate.

Here's the deal- EVERY DC mission will be heavily planned- far, far beyond anything in commercial aviation. It is a SPACEFLIGHT, not taking a crowd from JFK to SFO. Although we plan such flights heavily, a spaceflight will use resources and planning way beyond any airliner or corporate jet trip. The DC's cross-range will plotted for every rev. and abort plans will be made for every rev as well- otherwise, the flight will not go. Period.

I love the "bolt through the window" question. Here's what will happen... you'll either make it, or you won't. Simple as that.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: JAFO on 09/18/2012 05:26 am
Even if they divereted to an out of the way airport, a bigger problem would be clearing the airspace, especially during a heavy departure/arrival push. Would DC carry a transponder? If not, ATC wouldn't know where the vehicle was and where to send aircraft around it. They'd just have to scatter everyone.

(If DC did carry a transponder, would they squawk 1701?)
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: john smith 19 on 09/29/2012 05:45 pm
Shuttle did aborted.. to orbit. But still an abort. The big question would be about a pad abort, for example. Or an abort and ditch.

Interesting data point. That gives what, a 1 in 134 chance of an abort?
Roughly 0.75% of *all* flights ended in an abort. Of course on this basis 1.5% of all flights ended in a LOC

I'm going to stay with my original view that until DC starts flying it's impossible to state *categorically* DC will be more (or less) abort prone than Shuttle.

I *believe* its abort modes will be more benign than Shuttle simply because its stack design is different from Shuttles.

Sticking an ATC transponder (or 2 for redundancy) seems a pretty good idea. I'm not sure it's even *legal* to land at a commercial airport in the US without one and it's definitely the "neighborly" thing to do
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: JAFO on 09/29/2012 09:20 pm
I'm not sure it's even *legal* to land at a commercial airport in the US without one and it's definitely the "neighborly" thing to do

It is with prior arrangement. This can be as little as a radio call if it's not busy. If it's Newark at 1700 on Friday, fuggedaboudit.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: simonbp on 09/30/2012 06:22 am
(If DC did carry a transponder, would they squawk 1701?)

Only if it were named after OV-101... ;)
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: vulture4 on 10/01/2012 02:24 am
Runways of 3km or more are not common and busy commercial airports are loath to consent to be used for emergency landings of spacecraft. The entire world was surveyed repeatedly for runways for both Shuttle and CERV. The short answer is that they exist, but not in profusion. The Shuttle emergency landing sites around the world are well known; the majority are military fields that could be cleared quickly for an emergency landing. The approach cannot possibly be hand-flown, particularly with something like the DC which has very little aerodynamic reserve; everything from TIG to wheel stop must be autonomous. This was never possible with Shuttle, which predated even GPS. It had an autoland system but it was organizationally infeasible to even test it. In contrast the X-37 has so far made two completely autonomous landings with no significant problems.

I assume the problem is that any airport with a suitable runway, is that the airport likes to use them for landing airplanes. For instance, I assume you technically could land the DC at OHare, DFW, Atlanta, LAX, Denver, etc. But that would probably mean shutting down all aircraft operations for hours. And then, losing a major airport for hours means major air traffic delays that ripple across the entire system.

That's just entirely inaccurate.  Any time any aircraft declares an in-flight emergency, the airport in question can get clear and ready for them in seconds or tens of seconds.  This happens all the time right now without causing major ripples throughout the system.  Weather events cause a lot more havoc.  Second, even if DC did have to land quickly at some random airport, that would only close one runway for a short time, not the whole airport for a long time.  It's not a big craft, and it's non-toxic.

Thank you. I was about to post nearly exactly the same thing. All DC needs to know is where they are and where the runway is and their flight avionics will take it from there. Once notifying the tower that they are making an emergency landing the runway will be clear and ready for them when they get there. No airport will ever refuse an emergency landing to anybody, aircraft or spacecraft, once an emergency is declared.
In a conventional in-flight emergency that is correct, although it is hardly common and often closes runways for an extended period. However a spacecraft doesn't enter until it performs a deorbit burn and the burn would not be performed unless a destination field had already been chosen and the entry trajectory calculated. Consequently permission is needed in advance. The only unplanned entries I am aware of have been launch aborts and unmanned satellites that simply decayed without control (e.g. Skylab). The Shuttle was never in a situation where an emergency landing somewhere other than the three primary EOM sites was even considered. This isn't a big deal, there are always several opportunities per day. Maybe a penetration by orbital debris and a really high leak rate could do it, but that is a very low probability event.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: watermod on 10/02/2012 01:32 am
Quote
Robotbeat:
t= -ln(.1)/(.0001m^2*343m/s/(16m^3)) = about 18 minutes.
so enough time to slap some sort of sticky tough patch on the windscreen buying enough time to choose a landing spot.   
The tough one would be to be holed on the body behind some console.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Rocket Science on 10/02/2012 01:47 am
Quote
Robotbeat:
t= -ln(.1)/(.0001m^2*343m/s/(16m^3)) = about 18 minutes.
so enough time to slap some sort of sticky tough patch on the windscreen buying enough time to choose a landing spot.   
The tough one would be to be holed on the body behind some console.

If they are going to wearing launch and entry suits it helps negate the urgency of the situation…
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Robotbeat on 10/02/2012 02:13 am
Quote
Robotbeat:
t= -ln(.1)/(.0001m^2*343m/s/(16m^3)) = about 18 minutes.
so enough time to slap some sort of sticky tough patch on the windscreen buying enough time to choose a landing spot.   
The tough one would be to be holed on the body behind some console.

If they are going to wearing launch and entry suits it helps negate the urgency of the situation…
It takes a while to don a spacesuit.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: john smith 19 on 10/02/2012 09:23 am
t= -ln(.1)/(.0001m^2*343m/s/(16m^3)) = about 18 minutes.
Thank you for a very detailed answer whose result certainly surprised me (although I was aware of the sonic choking effect).

My specific concern was a wind shield puncture after reentry had *begun*.

I could accept that while DC was at a high angle of attack plasma entry would not be a serious issue but as its attitude leveled off I wondered if there would be a segment in the glidepath where it would be fast enough to be dealing with a plasma stream but slow enough to be at say <5deg nose up?

Assuming it survived that how would it cope with a fast moving (hypersonic?) air stream coming into the cabin? Is it survivable? Or would the disruption in aerodynamics be so severe it would become uncontrollable.

IIRC it is SOP in Soyuz returns to be wearing full pressure suits (not sure about helmets) and I would expect whatever is selected for CTS to retain this practice. 
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Garrett on 10/02/2012 10:04 am
Assuming it survived that how would it cope with a fast moving (hypersonic?) air stream coming into the cabin?

What makes you think the air stream would come into the cabin? If they're at high altitudes, then the outside pressure will still be much less than the cabin pressure, so there's no reason for the outside air stream to enter the cabin.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Rocket Science on 10/02/2012 12:36 pm
Quote
Robotbeat:
t= -ln(.1)/(.0001m^2*343m/s/(16m^3)) = about 18 minutes.
so enough time to slap some sort of sticky tough patch on the windscreen buying enough time to choose a landing spot.   
The tough one would be to be holed on the body behind some console.

If they are going to wearing launch and entry suits it helps negate the urgency of the situation…
It takes a while to don a spacesuit.
They will be wearing them prior to entering DreamChaser either on ISS or prior to launch. This was implemented after Challenger and a lesson not to be lost… (and yes I know Challenger was before ISS ;)
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: strangequark on 10/02/2012 03:25 pm
Assuming it survived that how would it cope with a fast moving (hypersonic?) air stream coming into the cabin?

What makes you think the air stream would come into the cabin? If they're at high altitudes, then the outside pressure will still be much less than the cabin pressure, so there's no reason for the outside air stream to enter the cabin.

Depends on what the stagnation pressure is, not the static pressure. This is very very rough, but the ambient air pressure can be as low as about 0.1psi, and you can still set up a positive pressure differential into the cabin.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Robotbeat on 10/02/2012 03:30 pm
Assuming it survived that how would it cope with a fast moving (hypersonic?) air stream coming into the cabin?

What makes you think the air stream would come into the cabin? If they're at high altitudes, then the outside pressure will still be much less than the cabin pressure, so there's no reason for the outside air stream to enter the cabin.

Depends on what the stagnation pressure is, not the static pressure. This is very very rough, but the ambient air pressure can be as low as about 0.1psi, and you can still set up a positive pressure differential into the cabin.
That is, if the hole is at the stagnation point...
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Rocket Science on 10/02/2012 05:49 pm
Assuming it survived that how would it cope with a fast moving (hypersonic?) air stream coming into the cabin?

What makes you think the air stream would come into the cabin? If they're at high altitudes, then the outside pressure will still be much less than the cabin pressure, so there's no reason for the outside air stream to enter the cabin.

Depends on what the stagnation pressure is, not the static pressure. This is very very rough, but the ambient air pressure can be as low as about 0.1psi, and you can still set up a positive pressure differential into the cabin.
That is, if the hole is at the stagnation point...
Interesting point…The X-20 Dynasoar was to have a boost cover over the windscreen that was to be jettisoned prior to landing. It would help with any hits, the Orbiter took some but it had a stout multi-pane screen…
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Robotbeat on 10/02/2012 07:56 pm
Assuming it survived that how would it cope with a fast moving (hypersonic?) air stream coming into the cabin?

What makes you think the air stream would come into the cabin? If they're at high altitudes, then the outside pressure will still be much less than the cabin pressure, so there's no reason for the outside air stream to enter the cabin.

Depends on what the stagnation pressure is, not the static pressure. This is very very rough, but the ambient air pressure can be as low as about 0.1psi, and you can still set up a positive pressure differential into the cabin.
That is, if the hole is at the stagnation point...
Interesting point…The X-20 Dynasoar was to have a boost cover over the windscreen that was to be jettisoned prior to landing. It would help with any hits, the Orbiter took some but it had a stout multi-pane screen…
My point was that there's no way a window would be put at the stagnation point. It's the hottest portion of the spacecraft during reentry, or rather it has the greatest thermal load.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Rocket Science on 10/02/2012 08:10 pm
Assuming it survived that how would it cope with a fast moving (hypersonic?) air stream coming into the cabin?

What makes you think the air stream would come into the cabin? If they're at high altitudes, then the outside pressure will still be much less than the cabin pressure, so there's no reason for the outside air stream to enter the cabin.

Depends on what the stagnation pressure is, not the static pressure. This is very very rough, but the ambient air pressure can be as low as about 0.1psi, and you can still set up a positive pressure differential into the cabin.
That is, if the hole is at the stagnation point...
Interesting point…The X-20 Dynasoar was to have a boost cover over the windscreen that was to be jettisoned prior to landing. It would help with any hits, the Orbiter took some but it had a stout multi-pane screen…
My point was that there's no way a window would be put at the stagnation point. It's the hottest portion of the spacecraft during reentry, or rather it has the greatest thermal load.
I get what you are saying Chris ex. bottom the the nose, I was stictly referring to hits on the screen...
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: vulture4 on 10/03/2012 02:49 pm
These considerations applied to the Shuttle also. There were a few minor dings but it never took a debris strike (anywhere on the vehicle) that would have penetrated the windows. After entry interface you are in the atmosphere and there is nothing to hit. That said, a windshield is unnecessary as cameras are perfectly adequate and in any case the approach and landing would be much safer under automatic control.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: john smith 19 on 10/03/2012 09:16 pm
These considerations applied to the Shuttle also. There were a few minor dings but it never took a debris strike (anywhere on the vehicle) that would have penetrated the windows. After entry interface you are in the atmosphere and there is nothing to hit. That said, a windshield is unnecessary as cameras are perfectly adequate and in any case the approach and landing would be much safer under automatic control.
There is at least one case of orbital debris hitting an Orbiter windshield panel and penetrating 2 of the 3 layers into the cabin. We're talking things down to paint fleck size. Replacing and inspecting them were significant refurbishment costs. I've not checked documents but IIRC gouges into at least the first layer were *routine* events.

Note that small diameter hole -> *very* high stress concentration -> potential crack growth

I'd agree windshields are unnecessary and autoland is perfectly viable (as it was with the orbiter once the autoland software upgrade was installed). However that means pilots don't get to fly the thing.

OTOH there is always the question of what happens if the camera fails.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Rocket Science on 10/03/2012 09:39 pm
These considerations applied to the Shuttle also. There were a few minor dings but it never took a debris strike (anywhere on the vehicle) that would have penetrated the windows. After entry interface you are in the atmosphere and there is nothing to hit. That said, a windshield is unnecessary as cameras are perfectly adequate and in any case the approach and landing would be much safer under automatic control.
There is at least one case of orbital debris hitting an Orbiter windshield panel and penetrating 2 of the 3 layers into the cabin. We're talking things down to paint fleck size. Replacing and inspecting them were significant refurbishment costs. I've not checked documents but IIRC gouges into at least the first layer were *routine* events.

Note that small diameter hole -> *very* high stress concentration -> potential crack growth

I'd agree windshields are unnecessary and autoland is perfectly viable (as it was with the orbiter once the autoland software upgrade was installed). However that means pilots don't get to fly the thing.

OTOH there is always the question of what happens if the camera fails.
An orbital debris protection cover could be placed over the windscreens while on orbit for long duration stays at ISS…
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: clongton on 10/04/2012 12:25 am
OTOH there is always the question of what happens if the camera fails.

Answer: Keep the windshield but keep it covered. If the camera goes out open the covers. The windshield is the backup.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: psloss on 10/04/2012 12:30 am
There is at least one case of orbital debris hitting an Orbiter windshield panel and penetrating 2 of the 3 layers into the cabin.
Source?
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Rocket Science on 10/04/2012 12:44 am
OTOH there is always the question of what happens if the camera fails.

Answer: Keep the windshield but keep it covered. If the camera goes out open the covers. The windshield is the backup.
A more elaborate option to protect the windscreen is an “eyelid” ala X-15A2.

http://www.ninfinger.org/models/vault2009/AF%20Musuem%20X-Plane%20Pics/X-15A2%20Eyelid.jpg
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: john smith 19 on 10/04/2012 02:58 pm
There is at least one case of orbital debris hitting an Orbiter windshield panel and penetrating 2 of the 3 layers into the cabin.
Source?

NASA TM-11059, although the document is numbered 110594

FILE REF 19950019959_1995119959.pdf
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: psloss on 10/04/2012 03:18 pm
There is at least one case of orbital debris hitting an Orbiter windshield panel and penetrating 2 of the 3 layers into the cabin.
Source?

NASA TM-11059, although the document is numbered 110594

FILE REF 19950019959_1995119959.pdf
What page in that source shows the event that penetrated through the thermal pane?
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: AnalogMan on 10/04/2012 03:56 pm
There is at least one case of orbital debris hitting an Orbiter windshield panel and penetrating 2 of the 3 layers into the cabin.
Source?

NASA TM-11059, although the document is numbered 110594

FILE REF 19950019959_1995119959.pdf
What page in that source shows the event that penetrated through the thermal pane?


Not the page on which this quote is taken from  ;)
 
"The Shuttle has never experienced an orbital impact that penetrated the windows or caused a through crack in the thermal pane. An impact of this magnitude would penetrate the aluminum skin of the fuselage as well, so the windows are not the most sensitive part of the vehicle."
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: john smith 19 on 10/04/2012 07:33 pm

Not the page on which this quote is taken from  ;)
 
"The Shuttle has never experienced an orbital impact that penetrated the windows or caused a through crack in the thermal pane. An impact of this magnitude would penetrate the aluminum skin of the fuselage as well, so the windows are not the most sensitive part of the vehicle."
So why bother quoting it?

Obviously I have mis remembered the original reference. I will note that the report only covers flights in the period 1981-1995.
Keep in mind this predates the discovery of what foam can do to RCC if it hit it hard enough.


I had thought the item was mentioned in the STS news reference manual but I was mistaken.  I distinctly recall reading it but cannot recollect where. That would suggest a usenet post, as nothing has turned up in a search of my shuttle files.

It would not have stuck in my mind if I had not trusted the commenter and it has certainly surprised me that I cannot find the reference but as I cannot I will withdraw the comment.

Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: psloss on 10/04/2012 07:49 pm

Not the page on which this quote is taken from  ;)
 
"The Shuttle has never experienced an orbital impact that penetrated the windows or caused a through crack in the thermal pane. An impact of this magnitude would penetrate the aluminum skin of the fuselage as well, so the windows are not the most sensitive part of the vehicle."
So why bother quoting it?
Because it directly contradicts your event claim and your source claim.

It would not have stuck in my mind if I had not trusted the commenter and it has certainly surprised me that I cannot find the reference but as I cannot I will withdraw the comment.
If something of that magnitude had happened, the response would have been much broader than a thread on Usenet.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: john smith 19 on 10/05/2012 12:39 pm
If something of that magnitude had happened, the response would have been much broader than a thread on Usenet.
I was merely repeating something I believed was common knowledge within the group of people who had an interest in the STS. I don't recall any comments at the time that "That can't happen. Procedures are too tight etc."

To clarify STS was a system I followed as the only *actual* refurbishable launch vehicle and a source of lessons to learn, IE what to avoid next time *if* you had a free hand. Most of my interest was its internal systems and failure modes. I reasoned if a lump of foam could hole the RCC wing leading edge what would it do to a windshield pane and did NASA have a backup plan. I'm unaware of any attempt to fire a foam sample at a windshield assembly but I doubt it would have ended well.

On another thread I described a possible new Shuttle design and this was one of the issues I covered.
http://forum.nasaspaceflight.com/index.php?topic=26576.60

As to such windshield  damage being investigated I'd certainly *hope* it would be have been. However I also would have expected evidence of fire damage on SRB O rings would have been investigated *before* they became an issue.

This is starting to move OT. It began with the idea that DC was more abort prone than aircraft and my view that it's not possible to state that given (according to Baldusi) that Shuttle made 1 abort to orbit in 134 missions and the DC stack is much simpler, making it much less prone to ascent damage 

If DC flies it will be the *only* aerospace vehicle where a pilot *could* make a landing from orbit and they'd probably want to do so looking out a windshield and not at a monitor screen (even a really nice one  :) ) rather than just switching on the autoland function and standing by in case anything happens.

The report I quoted indicates on orbit windscreen damage *is* real but fairly simple procedures can cut it substantially and assessment calculations seemed to be very conservative (where they improved before the programme was shut down?)

Shall we agree that bad things can happen and if you don't expect them (and have no mitigation plan) bad can become disastrous?
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: psloss on 10/05/2012 12:57 pm
If something of that magnitude had happened, the response would have been much broader than a thread on Usenet.
I was merely repeating something I believed was common knowledge within the group of people who had an interest in the STS. I don't recall any comments at the time that "That can't happen. Procedures are too tight etc."
You seem to be focused on the potential, which is fine except you threw out a 'fact' that's not factual.

As an example, there was always the potential for a RTLS abort; however, a claim that one happened is neither factual nor common knowledge.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: yg1968 on 10/05/2012 01:48 pm
A bit of an update on DC:
http://www.aviationweek.com/Article.aspx?id=/article-xml/AW_10_01_2012_p46-498007.xml&p=1

Quote
“We have plans to do a pad abort test in the coming months,” Sirangelo says. “Our vehicle has no black zones right now for abort from launch to orbit, and we can abort to a runway anywhere along the way. . . . None of the three of us has done any abort tests so far, and we need to all do that. We have that planned to retire that risk, not as one of the milestones but as work that we're doing separately.”
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: john smith 19 on 10/06/2012 08:30 am
A bit of an update on DC:
http://www.aviationweek.com/Article.aspx?id=/article-xml/AW_10_01_2012_p46-498007.xml&p=1

Quote
“We have plans to do a pad abort test in the coming months,” Sirangelo says. “Our vehicle has no black zones right now for abort from launch to orbit, and we can abort to a runway anywhere along the way. . . . None of the three of us has done any abort tests so far, and we need to all do that. We have that planned to retire that risk, not as one of the milestones but as work that we're doing separately.”
Given NASA's concerns about its handling characteristics this sounds like a *very* good use of (limited) company funds to address the things NASA is really worried about. A full vertical takeoff to horizontal landing should give both the hybrid motor and DC's control system a real workout.

In an ideal world a successful test *would* release funds for some of their discretionary items as well, but with the NASA budget that might be too much to hope for.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: yg1968 on 10/12/2012 01:55 am
This interview with Ed Mango has information about DC which I wasn't aware of:

http://www.floridatoday.com/apps/pbcs.dll/article?AID=2012310110043&nclick_check=1

Quote
Sierra Nevada is continuing to develop their Dream Chaser vehicle and they will basically fly that vehicle on automated landings at first and eventually with crew. They’re going to be flying those vehicles with automated landings throughout the middle of 2014, about 10 or so landings, at Edwards Air Force Base.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: john smith 19 on 10/12/2012 07:25 pm
Quote
Sierra Nevada is continuing to develop their Dream Chaser vehicle and they will basically fly that vehicle on automated landings at first and eventually with crew.
This makes a lot of sense. They've said they *want* to fly manually but this shakes out any problems with the backup before someone has to bet their lives on it.

People have talked a lot about the vehicle but I'd also expect they will have at least one pilot flying the simulator ready to get behind the controls.

I've really liked SNC's whole approach to their development programme. I hope the flight testing is aggressive enough to find any issues in the design but not aggressive enough to *break* it.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: BrightLight on 10/12/2012 08:16 pm
Quote
Sierra Nevada is continuing to develop their Dream Chaser vehicle and they will basically fly that vehicle on automated landings at first and eventually with crew.
This makes a lot of sense. They've said they *want* to fly manually but this shakes out any problems with the backup before someone has to bet their lives on it.


People have talked a lot about the vehicle but I'd also expect they will have at least one pilot flying the simulator ready to get behind the controls.

I've really liked SNC's whole approach to their development programme. I hope the flight testing is aggressive enough to find any issues in the design but not aggressive enough to *break* it.
Not to be a picker of nits, but I hope SNC tests at least part of DC to destruction. The best way IMHO to understand a complex system is to bound its limitations, like stressing sub-assemblies till they break.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Robotbeat on 10/12/2012 08:38 pm
Quote
Sierra Nevada is continuing to develop their Dream Chaser vehicle and they will basically fly that vehicle on automated landings at first and eventually with crew.
This makes a lot of sense. They've said they *want* to fly manually but this shakes out any problems with the backup before someone has to bet their lives on it.

Not to be a picker of nits, but I hope SNC tests at least part of DC to destruction. The best way IMHO to understand a complex system is to bound its limitations, like stressing sub-assemblies till they break.
People have talked a lot about the vehicle but I'd also expect they will have at least one pilot flying the simulator ready to get behind the controls.

I've really liked SNC's whole approach to their development programme. I hope the flight testing is aggressive enough to find any issues in the design but not aggressive enough to *break* it.
Edit your quotes, please!
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Robotbeat on 10/12/2012 09:24 pm
Okay, I'll delete this when fixed, but you can actually go /back/ to a previous post and edit it. Just click "Modify".
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: adrianwyard on 10/12/2012 11:34 pm
Does anyone else think that quote about a pad abort in the next few months sounds suspicious? Perhaps he was referring to a simulation; that I could believe.

Off the top of my head, this seems like a more likely testing progression:

+ Mid-altitude drop: lot's of time, right in the middle of the envelope. (repeat)
+ Higher drop: expand the envelope. (repeat)
+ Drop: Powered flight when in benign aerodynamic conditions (test transonic handling if not already covered previously in a dive) (repeat)
+ Drop: Powered flight with pull-up to mimic pad abort type flight, but at altitude so you can recover from problems and still land. (repeat).
And then:
+ Pad abort on a simulated Centaur from sea level.
+ Pad abort from sea level in cross-winds.
And then crewed test.
 
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: vt_hokie on 10/13/2012 12:05 am
This interview with Ed Mango has information about DC which I wasn't aware of:

http://www.floridatoday.com/apps/pbcs.dll/article?AID=2012310110043&nclick_check=1

Quote
Sierra Nevada is continuing to develop their Dream Chaser vehicle and they will basically fly that vehicle on automated landings at first and eventually with crew. They’re going to be flying those vehicles with automated landings throughout the middle of 2014, about 10 or so landings, at Edwards Air Force Base.

Hard to tell from this quote, but I wonder if they're still on track to start test flights later this year.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: john smith 19 on 10/13/2012 10:19 am
Not to be a picker of nits, but I hope SNC tests at least part of DC to destruction. The best way IMHO to understand a complex system is to bound its limitations, like stressing sub-assemblies till they break.
AFAIK SNC only have 1 *complete* vehicle built, which they built up form their original engineering test model (like the 5th Shuttle).

In an *ideal* test programme they would have 3. 1 in test (eventually to destruction), 1 being modified based on those tests and 1 spare. But with NASA funding as it is it's been a while since that's happened.

One of the reasons I've admired SNC's programme is that it has the furthest to travel and has the least resources (at least in this round) and has accomplished so much. This is a *very* ambitious vehicle in both aerodynamics *and* materials *and* engines (if your standards are very conservative) although in reality most elements have *some* flight heritage.

Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: happyflower on 11/29/2012 06:33 pm
I remember in the past that there was concern on DC docking to the ISS. Has that been resolved? If I remember correctly it had to do with DC not having a clear visual to the docking port and basically backing into its parking spot.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: clongton on 11/29/2012 11:18 pm
I remember in the past that there was concern on DC docking to the ISS. Has that been resolved? If I remember correctly it had to do with DC not having a clear visual to the docking port and basically backing into its parking spot.

They don't need to lookout the window. TV works just fine.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: catdlr on 12/04/2012 04:34 am
NewSpace 2012: Mark Sirangelo of Sierra Nevada Space Systems

Published on Dec 3, 2012 by spacevidcast

Mark Sirangelo, the CEO of Sierra Nevada Space Systems, talks about the current work done by SNC and their Dream Chaser crew vehicle currently under development.

http://www.youtube.com/watch?v=1nrtq07aa8I
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: adrianwyard on 01/17/2013 06:24 pm
According to an update from Lee Jay on L2, SNC is considering re-using the docking adapter after all (previous plan was to replace it each time).

I wonder if re-use will require the addition of thermal protection, i.e. a cover, or something akin to a body flap. This always struck me as desirable anyway as the hardware is in close proximity to the motor plumes and hot re-entry airstream. Even if you ignore heat-related damage, the plan is to exit the vehicle through this structure after landing, so you don't want it too toasty.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Lurker Steve on 01/17/2013 06:42 pm
According to an update from Lee Jay on L2, SNC is considering re-using the docking adapter after all (previous plan was to replace it each time).

I wonder if re-use will require the addition of thermal protection, i.e. a cover, or something akin to a body flap. This always struck me as desirable anyway as the hardware is in close proximity to the motor plumes and hot re-entry airstream. Even if you ignore heat-related damage, the plan is to exit the vehicle through this structure after landing, so you don't want it too toasty.

That's not the only entry / exit from the vehicle, is it ?
That's not really accessible when the vehicle is stacked on the pad, so you would think there is another entry point.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Lars_J on 01/17/2013 06:53 pm
Yeah, there must be a boarding hatch on top somewhere. I'm not sure why they want to exit through there rear docking hatch - the diameter isn't too big, right? In 1G they would need to crawl out on all four.

EDIT: I added a picture of the APAS hatch size, and SIMAC will be similar.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: docmordrid on 01/17/2013 07:43 pm
This artwork seems to indicate a top hatch about half way between the cabin and vertical stabilizer.

http://www.bbc.co.uk/blogs/thereporters/jonathanamos/snc_dreamchaser.jpg
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: adrianwyard on 01/17/2013 07:44 pm
There's a hatch on the 'roof' which they use to enter the vehicle on the pad.

Here's their concept of operations video which shows this, and also people exiting from the rear hatch after landing:

http://www.youtube.com/watch?v=i7yPVaNdGBw
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: adrianwyard on 01/18/2013 09:31 pm
According to an update from Lee Jay on L2, SNC is considering re-using the docking adapter after all (previous plan was to replace it each time).

I wonder if re-use will require the addition of thermal protection, i.e. a cover, or something akin to a body flap. This always struck me as desirable anyway as the hardware is in close proximity to the motor plumes and hot re-entry airstream. Even if you ignore heat-related damage, the plan is to exit the vehicle through this structure after landing, so you don't want it too toasty.

Apparently no thermal protection is planned even when adapters are to be reused.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: simonbp on 01/19/2013 02:54 am
Isn't the new standard smaller than ILIDS? That could make it easier to reuse/protect during reentry.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: adrianwyard on 01/19/2013 06:07 am
I don't believe the overall SIMAC size is smaller than before. If I read the following correctly, it lacks some of the iLIDS soft capture mechanism, and the tunnel will actually be wider:

http://www.aviationweek.com/Article.aspx?id=/article-xml/awx_12_26_2012_p0-528782.xml
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Confusador on 01/31/2013 12:09 am
So, Lockheed Martin is joining the project as a sub.  The way they've played it up for this press conference, I can't help but feel it's for political reasons as much as technical.  Either way, it's a good move.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Robotbeat on 01/31/2013 05:34 pm
So, Lockheed Martin is joining the project as a sub.  The way they've played it up for this press conference, I can't help but feel it's for political reasons as much as technical.  Either way, it's a good move.
I'd interpret it as giving outside folk confidence that SNC have people on their team (as subs) that unquestionably know what they're doing.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Lars_J on 02/04/2013 04:00 am
I moved this post from the update thread...

Once in LEO the Dream Chaser could fly back and its pilot dock it to the back of the payload module allowing the whole assembly to be pushed.

Why in the world would you disconnect, just to redock in LEO? You realize that DC only has a docking port in the rear, right?

The Dream Chaser's motors are at the back with the docking port.  So to perform a burn without destroying the cargo the cargo module has to be moved out of the way.

What burn?

If you are going to anywhere other than the LEO orbit the launch vehicle left you in you are going to need a burn.

This conversation should be in the Discussion thread rather than the Update thread.

I guess my point was, what about the cargo you just disconnected with... How are you re-docking with it after such a burn? Is attached by a rubber band?  :)
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: adrianwyard on 02/04/2013 04:21 am
It's not just non-LEO cases. If the concept of operations descriptions and videos are correct they are fired after Centaur sep, as a third stage, i.e. every mission. Even if that's not the case, then they're probably needed for orbit circularization, and also for de-orbit burn.

The analogy with OMS is probably apt - they are not just for abort.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Robotbeat on 02/04/2013 04:42 am
If Dream Chaser is around in ten years, I highly doubt it will still have a hybrid propulsion system. It just seems like a clumsy solution.

Virgin Galactic is abandoning hybrid propulsion for their next-gen spacecraft (i.e. the one after SpaceShipTwo).
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: A_M_Swallow on 02/04/2013 06:22 am
I moved this post from the update thread...

Once in LEO the Dream Chaser could fly back and its pilot dock it to the back of the payload module allowing the whole assembly to be pushed.

Why in the world would you disconnect, just to redock in LEO? You realize that DC only has a docking port in the rear, right?

The Dream Chaser's motors are at the back with the docking port.  So to perform a burn without destroying the cargo the cargo module has to be moved out of the way.

What burn?

If you are going to anywhere other than the LEO orbit the launch vehicle left you in you are going to need a burn.

This conversation should be in the Discussion thread rather than the Update thread.

I guess my point was, what about the cargo you just disconnected with... How are you re-docking with it after such a burn? Is attached by a rubber band?  :)

I suspect that rubber bands have insufficient strength at space temperatures.  A tether could be used, with a second tether attached to a strong point at the front of the Dream Chaser to keep the cargo from entering the hot exhaust gasses.

I had thought of adding a docking port to the back of the cargo module that pops up, allowing the Dream Chase to 'land' on the cargo and reverse in.  Two tethers with small winches are probably lighter.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Lars_J on 02/04/2013 04:31 pm
I was hoping that people would realize that my "rubber bands idea" was a JOKE. I'm just trying to point out that the DC is poorly suited as an external cargo delivery mechanism - at least for cargo of significant size/mass, especially if you DC needs to deliver it to a higher orbit.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: adrianwyard on 02/04/2013 05:12 pm
If Dream Chaser is around in ten years, I highly doubt it will still have a hybrid propulsion system. It just seems like a clumsy solution.

Virgin Galactic is abandoning hybrid propulsion for their next-gen spacecraft (i.e. the one after SpaceShipTwo).
Interesting. Is this public fact yet, or still just a rumor?
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: adrianwyard on 02/04/2013 05:34 pm
I was hoping that people would realize that my "rubber bands idea" was a JOKE. I'm just trying to point out that the DC is poorly suited as an external cargo delivery mechanism - at least for cargo of significant size/mass, especially if you DC needs to deliver it to a higher orbit.

This thread is becoming a little wacky! Irony is notoriously difficult to pull off online - and therefore confusing. It could be A_M_Swallow is trying to be funny by responding to your joke. Who knows?

Anyway, let's not use rubber bands in space.

After scratching my head at A_M_Swallow's initial redock suggestion, it occurred to me that he may have intended to say the DC turns around 180 degrees after sep and pulls the cargo out of the Centaur much as the Apollo CSM pulled out the LEM. This would require some new attachment mechanism on the nose of the DC.

Such a config would be more controllable than others because of where it shifts the center of mass.

But I worry about the attachment mechanism on the nose that this requires. Would the hardpoints/clamps be behind tile-cover doors? What if those doors fail to close?

Better to just admit DC is not going to be good at high-mass external cargo. The Dragon trunk solution is just superior.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: adrianwyard on 02/04/2013 05:42 pm
Back to questions on DC's hybrid motors:

The most authoritative info is in a SNC press release:
http://www.sncorp.com/press_more_info.php?id=429

"This same hybrid rocket will be used as the main propulsion system on the Dream Chaser during the orbital operations."

Chances are, the design has not changed since this October 2010 release.

Just for fun, here's a recap of the questions and our own tentative answers so far:

Q: Are you sure the DC hybrid's restart? RM1 on SpaceShipOne didn't, and these are supposedly RM1-derived.
A: That's correct, but these restart. SNC fired one motor three times as a CCDev milestone.

Q: Aren't they just for abort?
A: No. Recent ConOps CG video shows them being used for orbit insertion and de-orbit.

Q: Aren't there CG images that show an additional pair of nozzles at the rear as well as the hybrids?
A: Yes. Presumably these are older images.

Q: The SpaceX Dragon manages to use its Dracos as a combination of RCS and OMS for deorbit etc, why does DC need to use its hybrids?
A: Yes, Dragon works this way. A key piece of information we're lacking is the performance of DC's RCS jets. If they are proportionally similar to the Shuttle's RCS, it will need something analogous the shuttle's OMS engines.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: grakenverb on 02/04/2013 06:15 pm
There's a hatch on the 'roof' which they use to enter the vehicle on the pad.

Here's their concept of operations video which shows this, and also people exiting from the rear hatch after landing:

http://www.youtube.com/watch?v=i7yPVaNdGBw

Very interesting video.  I am assuming the crew will be relying on a video feed during the docking procedure. Has this been accomplished before with a crewed spacecraft?
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Lars_J on 02/04/2013 06:23 pm
Very interesting video.  I am assuming the crew will be relying on a video feed during the docking procedure. Has this been accomplished before with a crewed spacecraft?

Shuttle dockings did this all the time... The person in control would look at video screens (like the centerline camera) instead of looking out the window - Although the window was there as a backup.

See image http://cdn.theatlantic.com/static/infocus/endeavour060111/e24_4e006990.jpg
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: oiorionsbelt on 02/04/2013 07:33 pm
In that video there don't seem to be any T-0 umbilicals going to DC just to the spacecraft adapter. Is that correct?
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Robotbeat on 02/04/2013 07:39 pm
If Dream Chaser is around in ten years, I highly doubt it will still have a hybrid propulsion system. It just seems like a clumsy solution.

Virgin Galactic is abandoning hybrid propulsion for their next-gen spacecraft (i.e. the one after SpaceShipTwo).
Interesting. Is this public fact yet, or still just a rumor?
It's a public fact now, but I'm too lazy to find the link.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: yg1968 on 02/05/2013 03:01 pm
If Dream Chaser is around in ten years, I highly doubt it will still have a hybrid propulsion system. It just seems like a clumsy solution.

Virgin Galactic is abandoning hybrid propulsion for their next-gen spacecraft (i.e. the one after SpaceShipTwo).
Interesting. Is this public fact yet, or still just a rumor?
It's a public fact now, but I'm too lazy to find the link.

Here is the source:
Quote
LauncherOne will be powered by a two-stage, liquid-fueled rocket, now in initial development by Virgin Galactic. The same rocket also is intended to ultimately replace the non-reusable RM2 hybrid motor that will power the SS2 to suborbit, Virgin says.
http://www.aviationweek.com/Article.aspx?id=/article-xml/awx_07_11_2012_p0-475618.xml

See also:
http://forum.nasaspaceflight.com/index.php?topic=29405.msg928813#msg928813

Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: BrightLight on 02/05/2013 03:09 pm
If Dream Chaser is around in ten years, I highly doubt it will still have a hybrid propulsion system. It just seems like a clumsy solution.

Virgin Galactic is abandoning hybrid propulsion for their next-gen spacecraft (i.e. the one after SpaceShipTwo).
Interesting. Is this public fact yet, or still just a rumor?
It's a public fact now, but I'm too lazy to find the link.

Here is the source:
Quote
LauncherOne will be powered by a two-stage, liquid-fueled rocket, now in initial development by Virgin Galactic. The same rocket also is intended to ultimately replace the non-reusable RM2 hybrid motor that will power the SS2 to suborbit, Virgin says.
http://www.aviationweek.com/Article.aspx?id=/article-xml/awx_07_11_2012_p0-475618.xml

See also:
http://forum.nasaspaceflight.com/index.php?topic=29405.msg928813#msg928813

It's a public fact that Launcher One will have a liquid-fueled rocket, but it's not clear to me that DC will switch to a different type of rocket.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: yg1968 on 02/05/2013 03:15 pm
Yes that is correct. For the time being, there is no reason to believe that DC will change its hybrid motors.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Lee Jay on 02/05/2013 03:20 pm
Yes that is correct. There is no reason to believe that DC will change its hybrid motors.

Is there a need to?  It seems to be an elegant solution for their needs, even if it's a "clumsy" solution for a primary propulsion system designed to provide nearly all of your orbital velocity.  The hybrids provide a lot of thrust in a relatively small and simple package without requiring toxic propellants.  They wanted to go non-toxic and they need big thrust for aborts (sound's like solids), yet they'd also like to use them for orbital maneuvering with significant delta-V (need restartability and throttleability, which solids don't have).  They use the same oxidizer as the RCS too.  As long as they can make them stable, reliable, and restartable - which it seems they have already done - I don't see a reason to change them.  If they turn out to have problems, then that's another story.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: adrianwyard on 02/05/2013 06:30 pm
If Dream Chaser is around in ten years, I highly doubt it will still have a hybrid propulsion system. It just seems like a clumsy solution.

Virgin Galactic is abandoning hybrid propulsion for their next-gen spacecraft (i.e. the one after SpaceShipTwo).

Could you expand on 'clumsy'? Do you mean unreliable or dangerous compared to liquid solutions? You could argue hybrids are less clumsy if you're counting moving parts and/or numbers of components...

http://en.wikipedia.org/wiki/Hybrid_rocket
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Robotbeat on 02/05/2013 07:47 pm
Yes that is correct. For the time being, there is no reason to believe that DC will change its hybrid motors.
There is absolutely reason to believe, just not based on anything from SNC has said.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Lee Jay on 02/05/2013 08:04 pm
Yes that is correct. For the time being, there is no reason to believe that DC will change its hybrid motors.
There is absolutely reason to believe, just not based on anything from SNC has said.

What reason?  LauncherOne?  That seems totally unrelated to me as it needs 10 times the delta-V that Dream Chaser needs.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Robotbeat on 02/05/2013 08:12 pm
Yes that is correct. For the time being, there is no reason to believe that DC will change its hybrid motors.
There is absolutely reason to believe, just not based on anything from SNC has said.

What reason?  LauncherOne?  That seems totally unrelated to me as it needs 10 times the delta-V that Dream Chaser needs.
Hybrids have a host of disadvantages.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Lee Jay on 02/05/2013 08:16 pm
Yes that is correct. For the time being, there is no reason to believe that DC will change its hybrid motors.
There is absolutely reason to believe, just not based on anything from SNC has said.

What reason?  LauncherOne?  That seems totally unrelated to me as it needs 10 times the delta-V that Dream Chaser needs.
Hybrids have a host of disadvantages.
And some advantages.  And SNC owns the technology and seems to have developed them up to the necessary level for this vehicle.  The vehicle's entire internal composite structure is built around holding them.  Just because they have some theoretical disadvantages doesn't mean they aren't suited to the purpose for which they have been tasked in this vehicle.  What would you replace them with that's non-toxic, high-thrust, and very simple?
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Robotbeat on 02/05/2013 08:38 pm
They have a host of theoretical AND practical disadvantages.

You are "calling" me on this point, but I was just noting that it exists, I didn't want to steer the conversation in that direction.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Lee Jay on 02/05/2013 09:02 pm
They have a host of theoretical AND practical disadvantages.

You are "calling" me on this point, but I was just noting that it exists, I didn't want to steer the conversation in that direction.

Well, I want to understand the evidence behind your statements, "I highly doubt it will still have a hybrid propulsion system. It just seems like a clumsy solution."

These engines each produce around twice the thrust of each of the Shuttle OMS engines and can be lit at sea level.  Could N2O/Ethanol engines be made that could also do that and fit comfortably on the back of DC?
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Robotbeat on 02/05/2013 09:36 pm
Who cares? It's impractical for orbital use, IMHO. It's too low performance, it isn't any safer, reuse is actually /harder/, and a host of other issues.

They may get the square peg pounded into the round hole, but I bet they'll abandon hybrid before they get to orbit.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: notsorandom on 02/06/2013 03:32 am
Who cares? It's impractical for orbital use, IMHO. It's too low performance, it isn't any safer, reuse is actually /harder/, and a host of other issues.

They may get the square peg pounded into the round hole, but I bet they'll abandon hybrid before they get to orbit.
Wouldn't they pretty much add a new fuel grain to the combustion chamber, add the pyros for engine starts, and fill up the oxidizer tanks? I'm not sold on hybrids either but reuse doesn't seem that bad compaied to hypergols. I would more worried about the traditionally slow start time for hybrids which could be tricky in an abort. But I am sure SNC has that issue worked out.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Robotbeat on 02/06/2013 04:10 am
Yeah, even when you're designing a hybrid for reuse, you kind of need most of your engine (at least the combustion chamber--which has never been test-fired) replaced every time plus you need refueling (for the oxidizer), whereas with a liquid rocket designed for reuse, you simply fill up. Anyway, yeah, I just simply think they'll end up switching before orbit. It's not impossible to get a hybrid to work like they suggest, I just don't think it's terribly optimal.


By the way, have they ever started the hybrid motor in vacuum?
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Lee Jay on 02/06/2013 02:08 pm
By the way, have they ever started the hybrid motor in vacuum?

Yes.

http://www.sncorp.com/press_more_info.php?id=429 (http://www.sncorp.com/press_more_info.php?id=429)

"On September 21, 2010, SNC completed three successful test firings of a  single hybrid rocket motor in one day.  SNC’s newly opened rocket test  facility in San Diego County, California, hosted NASA personnel for a  rocket motor manufacturing review as well as the motor firings,  including one firing under vacuum ignition conditions.  The tests, which  simulated a complete nominal mission profile, demonstrated the multiple  restart capability of SNC’s proprietary hybrid rocket motor.  This same  hybrid rocket will be used as the main propulsion system on the Dream  Chaser during the orbital operations."
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Robotbeat on 02/06/2013 02:08 pm
By the way, have they ever started the hybrid motor in vacuum?

Yes.

http://www.sncorp.com/press_more_info.php?id=429 (http://www.sncorp.com/press_more_info.php?id=429)

"On September 21, 2010, SNC completed three successful test firings of a  single hybrid rocket motor in one day.  SNC’s newly opened rocket test  facility in San Diego County, California, hosted NASA personnel for a  rocket motor manufacturing review as well as the motor firings,  including one firing under vacuum ignition conditions.  The tests, which  simulated a complete nominal mission profile, demonstrated the multiple  restart capability of SNC’s proprietary hybrid rocket motor.  This same  hybrid rocket will be used as the main propulsion system on the Dream  Chaser during the orbital operations."
Thanks!
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: adrianwyard on 02/06/2013 03:51 pm
Vacuum restart is rather key as this is your ticket home, i.e. deorbit burn.

Q: does anyone know how such testing is done at sea level?
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Lars_J on 02/06/2013 04:08 pm
Vacuum restart is rather key as this is your ticket home, i.e. deorbit burn.

Q: does anyone know how such testing is done at sea level?

A vacuum chamber, obviously.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: adrianwyard on 02/06/2013 04:20 pm
Well, yes, that is obvious. The B-2 stand at Glenn claims to be the only facility capable of this. I don't recall SNC testing here, but perhaps they did.

http://facilities.grc.nasa.gov/b2/index.html
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Jim on 02/06/2013 04:31 pm
Well, yes, that is obvious. I discounted it because a vacuum chamber would become filled/pressurized with exhaust gases almost immediately, making it a poor analog for the vacuum case.

Anyone else have experience here?

There are  vacuum (100k ft) test facilities for engines and motors
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: HMXHMX on 02/06/2013 05:38 pm
Vacuum restart is rather key as this is your ticket home, i.e. deorbit burn.

Q: does anyone know how such testing is done at sea level?

A vacuum chamber, obviously.

The way you do it on a budget, presuming you are really interested in vac start/ignition issues rather than steady state operation, is to place a flat plate over the nozzle exit and pump out the chamber.  Then start like normal.  The cover is ejected downrange, obviously. We did this for the FALCON QuickReach Stage Two engine and it worked fine.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: adrianwyard on 02/06/2013 05:59 pm
This is heading off-topic, but a little internet sleuthing produced the following answer: For long-run steady-state vacuum testing the big stands, like Stennis' A-3 uses a Chemical Steam Generator to maintain low pressure during the test.

http://sscfreedom.ssc.nasa.gov/etd/ETDTestFacilitiesA3.asp

As far as the SNC test goes, a more careful read of the press release shows it occurred at their own facility: "SNC’s newly opened rocket test facility in San Diego County, California, hosted NASA personnel for a rocket motor manufacturing review as well as the motor firings, including one firing under vacuum ignition conditions."

Based on the following tour of the facility, I wonder if HMXHMX is right and this was just a startup test.

http://www.10news.com/news/rocket-motors-being-tested-inside-lakeside-quarry
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Patchouli on 02/07/2013 02:57 am
For extended missions, the Langley folks considered a "towed package" housed in the fairing. This was for the larger HL-42 variant, but if it were practical, could presumably be scaled down for the DC.

See "towed packed" in the following:
http://www.astronautix.com/craft/hl42.htm
...

The "towed package" in those pictures is just the LV fairing/payload adapter.


Some of the specs for the towed package seem to hint at a GEO or even lunar mission.
"Additional OMS/RCS LOX/methane propellants to provide a total orbit maneuver capability to the vehicle of 2980m/s (including reserves). "

I wonder if that's what they plan for Dream Chaser XL.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: docmordrid on 02/08/2013 08:46 pm
Are we certain Dream Chaser XL is still in the cards? Originally it was part of the ILOA mission, but they're now teamed with Golden Spike.

http://iloa.org/media/ILOA_GSC_2012.pdf
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: BrightLight on 02/11/2013 04:00 pm
This is where a partnership with LM pays off in time and money to get to certification (Does Boeing have similar capability for the ISS sims?):

from
http://www.aviationweek.com/Article.aspx?id=/article-xml/AW_02_11_2013_p32-545224.xml

"Crocker says he is already in discussions with Sierra Nevada about using the simulation lab to test Dream Chaser prox ops and docking at the International Space Station (ISS), both autonomously and piloted."
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Lurker Steve on 02/11/2013 08:05 pm
This is where a partnership with LM pays off in time and money to get to certification (Does Boeing have similar capability for the ISS sims?):

from
http://www.aviationweek.com/Article.aspx?id=/article-xml/AW_02_11_2013_p32-545224.xml

"Crocker says he is already in discussions with Sierra Nevada about using the simulation lab to test Dream Chaser prox ops and docking at the International Space Station (ISS), both autonomously and piloted."

I seem to remember an article about LM building a huge lab for Orion to simulate docking with the ISS. If some of that Billion dollar lab is used to support commerical, it's a good thing.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: BrightLight on 02/11/2013 10:58 pm
This is where a partnership with LM pays off in time and money to get to certification (Does Boeing have similar capability for the ISS sims?):

from
http://www.aviationweek.com/Article.aspx?id=/article-xml/AW_02_11_2013_p32-545224.xml

"Crocker says he is already in discussions with Sierra Nevada about using the simulation lab to test Dream Chaser prox ops and docking at the International Space Station (ISS), both autonomously and piloted."

I seem to remember an article about LM building a huge lab for Orion to simulate docking with the ISS. If some of that Billion dollar lab is used to support commerical, it's a good thing.

You are correct, LM has built a huge hardware-based docking simulator:
http://www.universetoday.com/84501/nasas-first-orion-capsule-and-new-space-operations-center-unveiled/
I look forward to seeing the DC (ETA??) on the dynamic motion arm  ;)
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: BrightLight on 02/12/2013 12:28 am
This is where a partnership with LM pays off in time and money to get to certification (Does Boeing have similar capability for the ISS sims?):

from
http://www.aviationweek.com/Article.aspx?id=/article-xml/AW_02_11_2013_p32-545224.xml

"Crocker says he is already in discussions with Sierra Nevada about using the simulation lab to test Dream Chaser prox ops and docking at the International Space Station (ISS), both autonomously and piloted."

I seem to remember an article about LM building a huge lab for Orion to simulate docking with the ISS. If some of that Billion dollar lab is used to support commerical, it's a good thing.

You are correct, LM has built a huge hardware-based docking simulator:
http://www.universetoday.com/84501/nasas-first-orion-capsule-and-new-space-operations-center-unveiled/
I look forward to seeing the DC (ETA??) on the dynamic motion arm  ;)
I didn't realize this but if SNC can get the DC into this simulator they will retire quit a bit of risk as they will be able to quickly demonstrate docking capability.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: BrightLight on 03/24/2013 06:22 pm
Another potential advantage to the DC is the added benefit of good cross range allowing for timely return when weather conditions are sub-optimal.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Prober on 04/10/2013 09:45 pm
How is this for a fine screen grab?
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Lars_J on 04/11/2013 02:02 am
Is that a screen grab from a new video?
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: docmordrid on 04/11/2013 03:08 am
That pic, or one within a few frames of it, has been online for at least a couple of years. I had it as a wallpaper for a while.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: docmordrid on 04/14/2013 12:15 am
http://www.spaceref.com/news/viewpr.html?pid=40511

Quote
Former NASA Astronaut Lee Archambault Joins Sierra Nevada Corporation's Dream Chaser Team
>
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Robotbeat on 05/24/2013 08:15 pm
Do we want to explore space, or do we just want pretty hardware?

If you're going to argue for Dreamchaser, do it on merits that actually matter.

Please don't be offended; I was simply agreeing with those who prefer Dream Chaser's looks to the looks of a capsule; I also happen to agree with those who say that Dream Chaser's soft landing capability has certain advantages over a capsule.

Mods, please feel free to move this post if it belongs elsewhere.
I'm posting here to complain instead of the update thread. ;)

Soft landing is something that may be a valid improvement, but I think this is exaggerated.

But actually, I think full reuse capability may be another... Dragon (and CST-100) uses an ablative heat shield that should have no problem surviving a lot of flights, but it's messy. Dreamchaser uses a fully reusable heatshield which, if carefully optimized and improved, could offer superior reusability over time. No charring, no big old mess that requires extensive clean-up. Now granted, I don't actually know enough to say for sure which one requires less turnaround maintenance, but this is what I think based on simply appearances (which isn't much, granted!).

(The hybrid propulsion system is a poor design choice, though, IMHO. Some sort of non-toxic liquid system would be much better performance, more control, and lower maintenance besides also being scalable.)

But looks by themselves shouldn't matter. It's all going to look pretty cool, and whatever is the most capable looks best to me!
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Lar on 05/24/2013 09:15 pm
But looks by themselves shouldn't matter. It's all going to look pretty cool, and whatever is the most capable looks best to me!

Roger that. Form follows function and beauty follows form. DC is the shape she is because that's a great shape for what she is tasked to do. And thus, beautiful.

Note the use of feminine pronoun. Dragon is handsome. DC is beautiful. :)  (CST on the other hand... .ewww)

Agree with you about engine choices... maybe they have some upgrades planned, who knows. But this engine type is one of SNC's core competencies, no? You go with what you know.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: QuantumG on 05/25/2013 01:22 am
Get Dreamchaser onto Falcon 9-R and we'll have the best of both worlds. :)
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Rocket Science on 05/25/2013 12:47 pm
Get Dreamchaser onto Falcon 9-R and we'll have the best of both worlds. :)

Yea Trent, I mentioned that a while back. It would be interesting from a cost standpoint on a fully reusable system as the “holy grail” of spaceflight. SpaceX still has a while to go to attain the track record of ULA’s “drama free” boring in a good way launches....
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Jcc on 05/25/2013 12:49 pm
Get Dreamchaser onto Falcon 9-R and we'll have the best of both worlds. :)


Yes, in terms of launch cost. We don't know the reuse/turnaround cost of the DC, but it should hopefully be a smaller percentage of the vehicle cost than the Shuttles. With the Shuttles they had to rebuild the engines nearly every time, and replace many heat shield tiles, etc, etc.

NASA plans to down select to one contractor for the ISS Crew contract, so it may be a tough choice between Dragon and DC if both prove out. Cost may be a significant factor (in my opinion it should be because NASA has other work to do as well). I'm guessing CST-100 wins only if both DC and Dragon fail.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Lar on 05/25/2013 01:44 pm
I'm guessing CST-100 wins only if both DC and Dragon fail.
In a logical, sensible world, yes. But the Senators[1] from Boeing may have something else to say.

1 - By moving their HQ to Chicago, they picked up another set of Senators to care about their fate...
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Soaring Habu on 05/25/2013 07:48 pm
Do we want to explore space, or do we just want pretty hardware?

If you're going to argue for Dreamchaser, do it on merits that actually matter.

Please don't be offended; I was simply agreeing with those who prefer Dream Chaser's looks to the looks of a capsule; I also happen to agree with those who say that Dream Chaser's soft landing capability has certain advantages over a capsule.

Mods, please feel free to move this post if it belongs elsewhere.
I'm posting here to complain instead of the update thread. ;)

Soft landing is something that may be a valid improvement, but I think this is exaggerated.

But actually, I think full reuse capability may be another... Dragon (and CST-100) uses an ablative heat shield that should have no problem surviving a lot of flights, but it's messy. Dreamchaser uses a fully reusable heatshield which, if carefully optimized and improved, could offer superior reusability over time. No charring, no big old mess that requires extensive clean-up. Now granted, I don't actually know enough to say for sure which one requires less turnaround maintenance, but this is what I think based on simply appearances (which isn't much, granted!).

(The hybrid propulsion system is a poor design choice, though, IMHO. Some sort of non-toxic liquid system would be much better performance, more control, and lower maintenance besides also being scalable.)

But looks by themselves shouldn't matter. It's all going to look pretty cool, and whatever is the most capable looks best to me!

You make good points; as for full reusability, I have difficulty seeing an ablative heatshield as reusable, but then, when I think of ablative heatshields, I’m thinking of the Apollo or Soyuz heatshield; maybe Dragon and CST-100 use different ablative materials that can be reused. I know next to nothing about Dragon and CST-100 after all!

I don’t really know how hard a capsule landing is versus a runway landing in a spaceplane, but I do feel that a spaceplane such as Dream Chaser offers a more controllable descent, and a more controllable landing, than a capsule, even if the spaceplane lands as a glider. I think the deceleration of a spaceplane rolling out on a runway would also be gentler than the deceleration of a capsule landing either on water or dry land. Feel free to correct me if I’m wrong!

I don’t know enough about Dream Chaser’s hybrid propulsion system to able to judge how good or bad it is; I only really know about the Shuttle’s propulsion system.

I know that looks by themselves don’t matter, it’s just that I prefer the looks of a spaceplane to the looks of a capsule; I’m a Shuttle fan as I’ve mentioned elsewhere, and the Shuttle was the first spacecraft to catch my attention and the one that got me interested in spaceflight, so it’s just a matter of personal preference. I’m certainly not saying that capsules are less capable than spaceplanes, or vice versa!
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Rabidpanda on 05/25/2013 09:58 pm
I'm guessing CST-100 wins only if both DC and Dragon fail.
In a logical, sensible world, yes. But the Senators[1] from Boeing may have something else to say.

Really?  I would think that CST-100 has a good chance of being ready sooner and costing less than Dreamchaser.  It's a much simpler system and Boeing received more than twice the money that SNC did for CCiCap.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Elmar Moelzer on 05/25/2013 11:18 pm

But actually, I think full reuse capability may be another... Dragon (and CST-100) uses an ablative heat shield that should have no problem surviving a lot of flights, but it's messy. Dreamchaser uses a fully reusable heatshield which, if carefully optimized and improved, could offer superior reusability over time. No charring, no big old mess that requires extensive clean-up. Now granted, I don't actually know enough to say for sure which one requires less turnaround maintenance, but this is what I think based on simply appearances (which isn't much, granted!).

Paradoxically the "fully reuseable" heatshield in the DC might require more maintenance than the simple shaped and easily inspected and replaced ablative heatshield on the Dragon.
IIRC, there was an article on NASA Spaceflight that mentioned several weeks that are needed just to inspect the DCs heatshield between flights.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: sdsds on 05/25/2013 11:34 pm
this is what I think based on simply appearances [...]
But looks by themselves shouldn't matter.

You're just a step away from what I believe to be the most effective rationale for Dream Chaser: call it what you will, it is reusablity that is "obvious," "evident," or "apparent." The technical truth matters to engineers; sadly the apparent truth is just as likely to be an influence on decision makers.

Propulsive landings may offer equally good reusability, but they don't make that reusability quite so apparent.

(I am not one who believes reusable spacecraft are necessarily more cost efficient; only that they are more "affordable" in the sense of being more appealing to those who control funding.)
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Lee Jay on 05/25/2013 11:41 pm
IIRC, there was an article on NASA Spaceflight that mentioned several weeks that are needed just to inspect the DCs heatshield between flights.

The total turnaround is expected to be around 2 months.  The TPS is expected to require vastly less maintenance than Shuttle did.  It's an improved system, the leading edge is a different material altogether, it's much smaller, and it's on the top of the rocket where it's subject to a vastly reduced debris environment.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: QuantumG on 05/25/2013 11:45 pm
I don't think Dragon is "as reusable" as DC. Dragon still uses scary hypergolics that require ground crews to take expensive safety precautions. Also, I wonder what the damage to the pad is going to be like.

Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Elmar Moelzer on 05/26/2013 12:23 am
The total turnaround is expected to be around 2 months.  The TPS is expected to require vastly less maintenance than Shuttle did.  It's an improved system, the leading edge is a different material altogether, it's much smaller, and it's on the top of the rocket where it's subject to a vastly reduced debris environment.
Yes and much of those 2 months maintenance time is due to the TPS.
The hypergolic fuels are a different matter, but I was simply talking about the TPS. Just because it is more reusable does not mean that it is easier or cheaper than an ablative heatshield.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: docmordrid on 05/26/2013 02:40 am
I don't think Dragon is "as reusable" as DC. Dragon still uses scary hypergolics that require ground crews to take expensive safety precautions. Also, I wonder what the damage to the pad is going to be like.

Granted there will be residuals, but won't the vast majority of the hypergols be used up by the SuperDraco's during the deceleration maneuvers and touchdown? Seems the ocen recovery crews are at a higher risk as they winch it onboard and stow it with much fuller tanks.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Elmar Moelzer on 05/26/2013 04:29 am
I was actually a but surprised by their choice of hypergolics for the superdracos. I do share the concerns about ground crews approaching the vehicle after landing and how all that complicates the process and refurbishment. I thought they were developing non toxic alternatives somewhere...
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Lee Jay on 05/26/2013 04:36 am
The total turnaround is expected to be around 2 months.  The TPS is expected to require vastly less maintenance than Shuttle did.  It's an improved system, the leading edge is a different material altogether, it's much smaller, and it's on the top of the rocket where it's subject to a vastly reduced debris environment.
Yes and much of those 2 months maintenance time is due to the TPS.

Source?  As far as I'm aware, they haven't said this.  They did say to me that they didn't expect the TPS to require a lot of maintenance.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Lar on 05/26/2013 04:47 am
I'm guessing CST-100 wins only if both DC and Dragon fail.
In a logical, sensible world, yes. But the Senators[1] from Boeing may have something else to say.

Really?  I would think that CST-100 has a good chance of being ready sooner and costing less than Dreamchaser.  It's a much simpler system and Boeing received more than twice the money that SNC did for CCiCap.

How much money Boeing got is likely to have zero (or negative) correlation to how efficient Boeing is.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: docmordrid on 05/26/2013 05:00 am
I was actually a but surprised by their choice of hypergolics for the superdracos. I do share the concerns about ground crews approaching the vehicle after landing and how all that complicates the process and refurbishment. I thought they were developing non toxic alternatives somewhere...

There are a couple of new green propellants in development, NOFBX being one, but they're far from proven not having flown yet. OTOH, hypergols are a known (if "dirty") quantity.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Jason1701 on 05/26/2013 05:05 am
I don't think Dragon is "as reusable" as DC. Dragon still uses scary hypergolics that require ground crews to take expensive safety precautions. Also, I wonder what the damage to the pad is going to be like.

Granted there will be residuals, but won't the vast majority of the hypergols be used up by the SuperDraco's during the deceleration maneuvers and touchdown? Seems the ocen recovery crews are at a higher risk as they winch it onboard and stow it with much fuller tanks.

Landing won't use much propellant since the parachutes remove most of the velocity.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: VatTas on 05/26/2013 07:20 am

Landing won't use much propellant since the parachutes remove most of the velocity.
Crewed Dragon wont use parachutes, except in abort situations.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: deltaV on 05/26/2013 05:42 pm
This is not the crewed dragon discussion thread.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Elmar Moelzer on 05/26/2013 11:27 pm

Source?  As far as I'm aware, they haven't said this.  They did say to me that they didn't expect the TPS to require a lot of maintenance.
I named one source earlier. There were other places that said the same thing.
But anyway, here is a direct link:
http://www.nasaspaceflight.com/2012/06/sierra-nevadas-5-year-partnership-nasa-progress-dream-chaser/

Quote
But regardless of the nature of Dream Chaser’s landing, Sierra Nevada is currently looking at a two-month turn-around of the vehicle between flights to LEO.

In those two months, large-scale sections of the spaceplane’s Thermal Protection System tiles would be replaced if needed – with whole tiles being replaced (even if just for a scratch) instead of repaired, as was the case with Shuttle.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Jcc on 05/27/2013 01:20 am
I'm guessing CST-100 wins only if both DC and Dragon fail.
In a logical, sensible world, yes. But the Senators[1] from Boeing may have something else to say.

Really?  I would think that CST-100 has a good chance of being ready sooner and costing less than Dreamchaser.  It's a much simpler system and Boeing received more than twice the money that SNC did for CCiCap.

How much money Boeing got is likely to have zero (or negative) correlation to how efficient Boeing is.

Dreamchaser will be ready to fly in 2017 according to plan. CST-100 is also planned to do manned tests in 2017. Dragon is supposed to be ready by 2015, according to their ever-optimistic plan. NASA has now reserved Soyuz seats through the end of 2017 or mid-2018, which I think represents a schedule slip. If NASA had needed  Commercial Crew by 2016, it would have eliminated 2 out of 3 competitors, which would not have been politically acceptable, nor meet their  desire for competition.

Was there ever a plan by SNC to have Dreamchaser + Atlas V 402 ready earlier than 2017, given a higher level of funding?
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Lee Jay on 05/27/2013 01:29 am
Was there ever a plan by SNC to have Dreamchaser + Atlas V 402 ready earlier than 2017, given a higher level of funding?

Yes.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Lee Jay on 05/27/2013 01:34 am

Source?  As far as I'm aware, they haven't said this.  They did say to me that they didn't expect the TPS to require a lot of maintenance.
I named one source earlier. There were other places that said the same thing.
But anyway, here is a direct link:
http://www.nasaspaceflight.com/2012/06/sierra-nevadas-5-year-partnership-nasa-progress-dream-chaser/ (http://www.nasaspaceflight.com/2012/06/sierra-nevadas-5-year-partnership-nasa-progress-dream-chaser/)

Quote
But regardless of the nature of Dream Chaser’s landing, Sierra Nevada is currently looking at a two-month turn-around of the vehicle between flights to LEO.

In those two months, large-scale sections of the spaceplane’s Thermal Protection System tiles would be replaced if needed – with whole tiles being replaced (even if just for a scratch) instead of repaired, as was the case with Shuttle.

My interview was the source for that, and the text does not say what you are saying it does.  This method was one way to reduce TPS maintenance, and as it plainly says, this is only "if necessary".  Also, as it says this would take place during those two months, which is not the same at all as it taking "much of those 2 months" to do that maintenance.  Obviously, all maintenance would take place during the 2-month turnaround time, but that would also include things like transportation and integration with the next LV.  There are many other tasks that would also take place in those 2 months.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: newpylong on 05/28/2013 02:24 am
Was there ever a plan by SNC to have Dreamchaser + Atlas V 402 ready earlier than 2017, given a higher level of funding?

Yes.

Can you please provide a source on this? It was my understanding Boeing and SNC were both looking at 2017 all along and SpaceX 2015.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Lee Jay on 05/28/2013 01:22 pm
Was there ever a plan by SNC to have Dreamchaser + Atlas V 402 ready earlier than 2017, given a higher level of funding?

Yes.

Can you please provide a source on this? It was my understanding Boeing and SNC were both looking at 2017 all along and SpaceX 2015.

Mark Sirangelo - see the SNC DC L2 thread.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Lurker Steve on 05/28/2013 01:51 pm
I'm guessing CST-100 wins only if both DC and Dragon fail.
In a logical, sensible world, yes. But the Senators[1] from Boeing may have something else to say.

1 - By moving their HQ to Chicago, they picked up another set of Senators to care about their fate...

Wrong. My senators could care less about what happens in my state. Dick Durbin in particular has other ambitions. He wants Harry Reid's job. Our junior senator, Mark Kirk, is still in his first term and is recovering from a stroke. He hasn't been corrupted by that type of thinking yet.

It doesn't even help to have Obama from our state. We still send more money to Washington than we receive.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: catdlr on 05/28/2013 11:01 pm
An Inside Look at SNC's Dream Chaser

Published on May 28, 2013
Cheryl McPhillips, the NASA Commercial Crew Program partner manager for Sierra Nevada Corporation (SNC), discusses the uniqueness of the company's Dream Chaser spacecraft and the milestones SNC plans to meet during the agency's Commercial Crew Integrated Capability (CCiCap) initiative.

http://www.youtube.com/watch?v=DheVO2qwzsI
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Lee Jay on 05/28/2013 11:12 pm
A lot of that video was the old version of the conops video, and in some ways it was technically incorrect, especially the crew access at the pad.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Elmar Moelzer on 05/28/2013 11:59 pm

My interview was the source for that, and the text does not say what you are saying it does.  This method was one way to reduce TPS maintenance, and as it plainly says, this is only "if necessary".  Also, as it says this would take place during those two months, which is not the same at all as it taking "much of those 2 months" to do that maintenance.  Obviously, all maintenance would take place during the 2-month turnaround time, but that would also include things like transportation and integration with the next LV.  There are many other tasks that would also take place in those 2 months.
It was a bit ambiguous. There were other articles saying essentially the same thing...
Anyway, I said weeks for the TPS maintenance and not that it would be the whole two months. Obviously other things have to happen in those two months as well. Anway, may point was that the reusable heatshield on the DC might not need much less maintenance than the ablative heatshield in Dragon (which is not only smaller, but also a much simpler shape and can allegedly be used for dozens of missions).
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: spectre9 on 05/29/2013 01:56 pm
Discussion out of the update thread.

McPhillips says that SNC is trying to get to CDR during the CCiCap period. That's news to me. NASA isn't paying them to get to CDR which means that SNC would have to fund the difference.

What does this really mean?

They've already been cut or that they're being given the chance however unlikely that it might be to find the money from private investment?

I thought NASA could make up the money later if/when they get the $820 million requested.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: newpylong on 05/29/2013 02:43 pm
To me, they are going to continue advancing the vehicle as quickly as possible past CCiCap requirements, possibly on their own dime in an effort to prevent a down select.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: AnalogMan on 05/29/2013 03:16 pm
[transferred from the update thread]

As already noted completion of CDR was included in the the optional milestones in SNC's CCiCAP agreement - this is a summary from the SAA:

"In the Commercial Crew integrated Capability (CCiCap) phase, SNC will complete the Dream Chaser Space System (DCSS) detailed design, start certification using NASA's requirements and standards, build hardware, and conduct significant risk reduction. These activities will result in the completion of integrated system safety reviews, integrated systems hardware testing, additional unpiloted Engineering Test Article (ETA) flights, and preparation for an Critical Design Review (CDR) during the base period. SNC has identified additional optional milestones that include a CDR, an SOV powered drop test, a pad abort test, and an uncrewed orbital vehicle (0V) flight test, culminating in a [redacted] orbital crewed demonstration flight."

http://commercialcrew.nasa.gov/document_file_get.cfm?docid=634 (http://commercialcrew.nasa.gov/document_file_get.cfm?docid=634)

Recently during the 2013 2nd Quarter meeting of the ASAP (at the start of April) the following comments were made regarding the possibility of exercising some optional milestones

COMMERCIAL CREW UPDATE
[...] "One of ASAP’s topics of interest has been the optional milestones. If NASA decides to exercise these milestones, what kind of work would be done and would there be any possibility that it could include crewed flights? Mr. McAlister [Director of Commercial Space Flight Development] said that there is still no intent to do crewed flights under a Space Act Agreement (SAA). Any crewed flights would be under contract. However, the Program wants to hold out the possibility of exercising a subset of the optional milestones to keep the contractors moving forward on useful work."

http://oiir.hq.nasa.gov/asap/documents/ASAP_Public_Meeting_Minutes_2nd-Qtr-2013 (http://oiir.hq.nasa.gov/asap/documents/ASAP_Public_Meeting_Minutes_2nd-Qtr-2013)

Perhaps NASA have been discussing with SNC the possibility of funding the optional CDR milestone after all.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Lurker Steve on 05/29/2013 04:09 pm
Why would the CDR be dependent on NASA funding ???
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: yg1968 on 05/29/2013 04:10 pm
COMMERCIAL CREW UPDATE
[...] "One of ASAP’s topics of interest has been the optional milestones. If NASA decides to exercise these milestones, what kind of work would be done and would there be any possibility that it could include crewed flights? Mr. McAlister [Director of Commercial Space Flight Development] said that there is still no intent to do crewed flights under a Space Act Agreement (SAA). Any crewed flights would be under contract. However, the Program wants to hold out the possibility of exercising a subset of the optional milestones to keep the contractors moving forward on useful work."

http://oiir.hq.nasa.gov/asap/documents/ASAP_Public_Meeting_Minutes_2nd-Qtr-2013 (http://oiir.hq.nasa.gov/asap/documents/ASAP_Public_Meeting_Minutes_2nd-Qtr-2013)


I had trouble opening this document in a web browser. But I managed to open it by saving it on my computer and opening it with Acrobat reader. In any event, here is the pdf file if you are having trouble opening with a web browser (like me).
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Orbiter on 06/08/2013 04:22 am
Not a particularly technical question -- but I wonder if future SNC's Dream Chasers will have their names displayed on their vehicles in a shuttle-esque style? Doesn't look like the ETA does, so it makes me think otherwise.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: vt_hokie on 06/09/2013 03:00 pm
Not a particularly technical question -- but I wonder if future SNC's Dream Chasers will have their names displayed on their vehicles in a shuttle-esque style? Doesn't look like the ETA does, so it makes me think otherwise.

I would put money on the orbital vehicles having them displayed.  But let's just hope the program gets that far!
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Overflow on 06/11/2013 01:46 am
Not a particularly technical question -- but I wonder if future SNC's Dream Chasers will have their names displayed on their vehicles in a shuttle-esque style? Doesn't look like the ETA does, so it makes me think otherwise.

I hope so. I believe they would get more fans that way as well. It will allow people to connect more to the spacecrafts and missions, generating more support from the public.

Another thing to add, is that after all these tests are complete, I wonder where this test craft will end up.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Overflow on 06/11/2013 01:54 am
An Inside Look at SNC's Dream Chaser

Published on May 28, 2013
Cheryl McPhillips, the NASA Commercial Crew Program partner manager for Sierra Nevada Corporation (SNC), discusses the uniqueness of the company's Dream Chaser spacecraft and the milestones SNC plans to meet during the agency's Commercial Crew Integrated Capability (CCiCap) initiative.

http://www.youtube.com/watch?v=DheVO2qwzsI

Pretty cool picture..

Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Lobo on 07/17/2013 07:01 pm
Does anyone have the dimensions of the pressure vessel inside of Dreamchaser?

I was just noticing that DC's pressurized/habitable volume is only about 2 m^3 less than that of the first Cygnus module.

Could there be a cargo version of DC that in essence took over for Cygnus?  At least phase 1 Cygnus?
If they put a CBM adaptor on it?

Phase 1 Cygnus is only 2mt to LEO.  I'd think a stripped down Dreamchaser with just an open cargo volume inside could do that?

Just wondering if DC could actually do both cargo and crew like Dragon will be able to, if down the road NASA were to considering having commercial providers doing both roles.

Phase 2 Cygnus has more volume, but only 2.7mt of cargo. 
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Lars_J on 07/17/2013 07:15 pm
Could there be a cargo version of DC that in essence took over for Cygnus?  At least phase 1 Cygnus?
If they put a CBM adaptor on it?

There could be a mostly (or all-) cargo version of DC, but I don't think it would use CBM - the tail isn't big enough for it. But there is no absolute rule that a cargo vehicle can't deliver cargo through a narrower hatch.

Progress and ATV deliver cargo through a smaller hatch.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: pathfinder_01 on 07/17/2013 07:31 pm
Does anyone have the dimensions of the pressure vessel inside of Dreamchaser?

I was just noticing that DC's pressurized/habitable volume is only about 2 m^3 less than that of the first Cygnus module.

Could there be a cargo version of DC that in essence took over for Cygnus?  At least phase 1 Cygnus?
If they put a CBM adaptor on it?

Phase 1 Cygnus is only 2mt to LEO.  I'd think a stripped down Dreamchaser with just an open cargo volume inside could do that?

Just wondering if DC could actually do both cargo and crew like Dragon will be able to, if down the road NASA were to considering having commercial providers doing both roles.

Phase 2 Cygnus has more volume, but only 2.7mt of cargo. 

Couple of issues.

1. The ISS's cargo is volume limited not mass limited so losing the extra volume of Cygnus would be significant . Food and clothing is bulky not massive and Cygnus also handles trash disposal via destructive reentry. 

2.  Dream chaser was one of the COTS contestants and is built to operate automatically and could deliver cargo.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Patchouli on 07/17/2013 11:00 pm
Does anyone have the dimensions of the pressure vessel inside of Dreamchaser?

I was just noticing that DC's pressurized/habitable volume is only about 2 m^3 less than that of the first Cygnus module.

Could there be a cargo version of DC that in essence took over for Cygnus?  At least phase 1 Cygnus?
If they put a CBM adaptor on it?

Phase 1 Cygnus is only 2mt to LEO.  I'd think a stripped down Dreamchaser with just an open cargo volume inside could do that?

Just wondering if DC could actually do both cargo and crew like Dragon will be able to, if down the road NASA were to considering having commercial providers doing both roles.

Phase 2 Cygnus has more volume, but only 2.7mt of cargo. 

Couple of issues.

1. The ISS's cargo is volume limited not mass limited so losing the extra volume of Cygnus would be significant . Food and clothing is bulky not massive and Cygnus also handles trash disposal via destructive reentry. 

2.  Dream chaser was one of the COTS contestants and is built to operate automatically and could deliver cargo.


I remember reading Progress and the Shuttle rarely used their full up mass capability as they'd run out of space before they ran out of payload.
Actually I don't think they really ever used the full payload of the Shuttle on ISS.
Kibo came close though.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Lobo on 07/17/2013 11:32 pm
Does anyone have the dimensions of the pressure vessel inside of Dreamchaser?

I was just noticing that DC's pressurized/habitable volume is only about 2 m^3 less than that of the first Cygnus module.

Could there be a cargo version of DC that in essence took over for Cygnus?  At least phase 1 Cygnus?
If they put a CBM adaptor on it?

Phase 1 Cygnus is only 2mt to LEO.  I'd think a stripped down Dreamchaser with just an open cargo volume inside could do that?

Just wondering if DC could actually do both cargo and crew like Dragon will be able to, if down the road NASA were to considering having commercial providers doing both roles.

Phase 2 Cygnus has more volume, but only 2.7mt of cargo. 

Couple of issues.

1. The ISS's cargo is volume limited not mass limited so losing the extra volume of Cygnus would be significant . Food and clothing is bulky not massive and Cygnus also handles trash disposal via destructive reentry. 

2.  Dream chaser was one of the COTS contestants and is built to operate automatically and could deliver cargo.


I remember reading Progress and the Shuttle rarely used their full up mass capability as they'd run out of space before they ran out of payload.
Actually I don't think they really ever used the full payload of the Shuttle on ISS.
Kibo came close though.

Yea, probably the volume of Cygnus would be something that they'll want after ATV and HTV stop flying.  (Although, it's sort of screwy that ESA and JAXA developed those craft to fly only like 5 times?  You'd think they could be leverged into continuing service of one or the other on their own dime for their parts in the ISS operation for as long as it operates.)

And i don't think Cygnus is that expensive.  However, if there were two CCiCAP winners chosen, they could have four commercial providers running to the ISS.  Each with a pretty low flight rate.  Be nice to possibly see like two providers with better flight rates.   And I do like Dream Chaser.  So I was wondering if there was potentially other roles she could do that might come into play.

Although, in that same vein, is there anything cargo-Dragon does that a cargo Dreamchaser couldn't do?  DC has 16m^3 of pressurized volume vs. 10m^3 for Dragon.  And both could do downmass.  Is there anything that needs the wider CBM hatch to move through vs. the smaller docking hatch for either?

CST-100 sort of seems like they may be the odd man out.  It's a fine design, for sure.  But I can't imagine them being as cheap or versitile (both cargo and crew) as Dragon, and they won't have the dissimilar redundancy and cool factor of Dreamchaser. 

Maybe they could do some combined crew and cargo/downmass contracts for SNC and SpaceX, with some additional large volume cargo-only contracts for OSC?  3 providers total?  After ATV and HTV stop flying, might there be enough work for all three?
Instead of one dedicated commercial crew contract, you have two "1/2" crew contracts, combined with two "1/2" cargo/downmass contracts.

Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: zaitcev on 09/05/2013 07:01 pm
This is obviously a trivial thought that is very probably was discussed previously, but did anyone consider if Dream Chaser can be put on top of something like Delta IV CCB (with solid boosters if needed)? It has its own propulsion, so it's not entirely a single stage to orbit deal. I do not know how much velocity can DC's engines add as planned today, and how much is feasible with liquid engines.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: vt_hokie on 10/30/2013 05:23 am
One thing I've been wondering about is the safety of the hybrid motors while the DC orbiter is docked to ISS.  With the aft docking port, the two hybrid OMS engines have their nozzles pointed straight at the station in close proximity, so I assume any inadvertent ignition would be catastrophic.  Is there any additional hazard vs the shuttle or other spacecraft which visit ISS?
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: newpylong on 10/30/2013 03:38 pm
One thing I've been wondering about is the safety of the hybrid motors while the DC orbiter is docked to ISS.  With the aft docking port, the two hybrid OMS engines have their nozzles pointed straight at the station in close proximity, so I assume any inadvertent ignition would be catastrophic.  Is there any additional hazard vs the shuttle or other spacecraft which visit ISS?

I don't see much difference between accidental ignition and accidental collision (by any spacecraft)? Both real threats with safeguards in place...
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: adrianwyard on 11/05/2013 01:46 am
I may be mistaken, but I think the free flight of DC, with its comparatively low landing speed of 160 knots highlighted something about the aerodynamics of lifting-bodies that I had not realized before.

While a given shape may have low L/D, and therefore a high stall-speed, it may also be able to A] flare at high-speed, and then B] maintain that nose-up attitude, bleeding off speed and then touch down at a speed that's below its (level-flight, non-flared) stall speed.

We tend to think of 'flying' as meaning level-flight (even with gliders) which lifting bodies like DC are rubbish at. While all aircraft flare to some degree, you expect them to also be able to fly down to ground level. But if a shape can A] drop like a stone, and B] flare to land at reasonable speed, then its inability to 'fly' down to the runway doesn't really matter.

Am I close to the mark here?
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Lars_J on 11/05/2013 01:52 am
Yes. That's pretty much how the Shuttle flew, and any glider with a poor glide ratio does. It does however mean that you need to flare and land at the right speed, otherwise... not good.

ANY aircraft can use the technique you suggest to land at or below stall speed - but it is not a particularly safe way to fly.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Rocket Science on 11/05/2013 11:40 am
I’m a little confused at what you both are writing about, level flight..? From my experience flying both gliders and powered aircraft and in the absence of a thermal, how are you going to maintain level flight without adding power? You are always trading altitude for airspeed...

And what do you mean landing at the “right speed”? I fly by the numbers, which are there for a reason... Just asking...
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Garrett on 11/05/2013 02:53 pm
And what do you mean landing at the “right speed”?
I think he means flaring at an ideal combination of speed, angle and altitude so that you land gently. An almost perfect example is the way birds land on a wire or branch. Here's a video of a robot bird doing the same thing:
http://www.youtube.com/watch?v=2QqTcQ1BxIs
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: adrianwyard on 11/05/2013 03:25 pm
In retrospect saying "Level-flight" was a confusing way to say "zero pitch wrt airstream."

What I've noticed is not that profound: the speed range that a lifting body flies in a significant flare, i.e. nose pitched up attitude is large, and extends down to a speed which is much lower than the zero-pitch stall speed.

Rather than one stall speed, a lifting body has a wide range of them depending on pitch.

This is true of all gliders, but with more familiar high L/D shapes the numbers are smaller and closer together. i.e. a sailplane might be able to descend to a landing with zero pitch and not stall. Not so with DC.

And by "flare at land at right speed" I think Lars means timing is key because you only have a limited time in the flare - speed drops so rapidly. If you flare too high, you'll reach a nice slow landing speed, but you'll still be above the runway, not on it,  and then ... not good.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Rocket Science on 11/05/2013 04:38 pm
In retrospect saying "Level-flight" was a confusing way to say "zero pitch wrt airstream."

What I've noticed is not that profound: the speed range that a lifting body flies in a significant flare, i.e. nose pitched up attitude is large, and extends down to a speed which is much lower than the zero-pitch stall speed.

Rather than one stall speed, a lifting body has a wide range of them depending on pitch.

This is true of all gliders, but with more familiar high L/D shapes the numbers are smaller and closer together. i.e. a sailplane might be able to descend to a landing with zero pitch and not stall. Not so with DC.

And by "flare at land at right speed" I think Lars means timing is key because you only have a limited time in the flare - speed drops so rapidly. If you flare too high, you'll reach a nice slow landing speed, but you'll still be above the runway, not on it,  and then ... not good.
Ok, I think I understand what you are referring to. It's called “flying it onto the runway” using a low power setting, as opposed to a full stall landing. You have to be careful with that type of landing as you can land nose wheel first and wheelbarrow down the runway.
With a glider with a single central main gear you can manage it using the speed brakes which increases your rate of descent.

When it comes to stalling remember you can have a high speed stall as well as a low speed one.
Rounding out or flaring too soon (been there, done that)  ;D  will result in “rattling your fillings” as you bounce and using power again you can gentle set down.

DC flared nicely and seemed like she was floating down onto her “main”. Upon landing she would have held her nose high to bleed off speed and de-rotate for the nose skid to touchdown. Pretty much like Shuttle did for 30 years.

Now if you are talking about “go round” then we’re going to open that whole debate again...

edit:typo

P.S. Adrian, I found the front skid deploy as a water ski interesting. Would mind seeing the results of that from a water tank tests if it has any effect or would the "shoe" cause it to nose in...
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Lars_J on 11/06/2013 04:23 am
Switching gears here - I have a Q regarding the hybrid engines that will be attached to the sides of DC. Would they only be used during launch abort? Or are they also used for in-space propulsion and de-orbit?
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: adrianwyard on 11/06/2013 07:30 am
They are apparently analogous to Shuttle OMS, so yes to all of those, including being in essence the third stage each launch. So a lot is dependent upon them!

We believe they gimbal and so it seems likely they could be used one at a time (if fired pointing through the vehicle's center of mass). This would provide redundancy should one fail.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Lars_J on 11/07/2013 05:07 pm
They are apparently analogous to Shuttle OMS, so yes to all of those, including being in essence the third stage each launch. So a lot is dependent upon them!

We believe they gimbal and so it seems likely they could be used one at a time (if fired pointing through the vehicle's center of mass). This would provide redundancy should one fail.

That would be quite a significant gimbal range, if true. Close to 45 degrees, judging by the attached image.

Has there been any previous history of hybrid rockets firing in a micro-gravity environment?
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: adrianwyard on 11/07/2013 06:22 pm
Agreed, based on that graphic. But the engine bells have been depicted angled appropriately in other places:

http://www.astronautix.com/craft/hl20.htm
http://en.wikipedia.org/wiki/HL-20

If the centered position of the bells had them pointing half-way outward you might be able to point them straight aft, and also through the center of mass when at max deflection.

I'm not aware of hybrid's having been fired in microgravity, but of course once you're past ignition the environment is no longer microgravity by a long shot, and my guess is ground-testing even at 1g doesn't affect the results that much. Firing the motor vertically gives you zero lateral forces, just like microgravity.

I suppose the nozzle may not have been fired in vacuum before.

I must admit that based on what's been disclosed, the hybrid motors on DC are a worry, especially if you believe the rumors of trouble with SpaceShipTwo's motor (built by SNC). The image of chunks of rubber pulling away internally and getting lodged in the nozzle throat is not a pretty one. And yet, this physical failure could happen on any solid motor too, and we man-rated them. I guess it comes down the the physical properties of the propellant.

Testing is ongoing, so that's a good sign:

http://www.sncorp.com/press_more_info.php?id=549
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Lee Jay on 11/07/2013 07:04 pm
I suppose the nozzle may not have been fired in vacuum before.

In ground testing, they've been vacuum started.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: adrianwyard on 11/07/2013 07:56 pm
Good to know. Thanks.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: edkyle99 on 11/14/2013 12:09 am
So what's next.  Is Dream Chaser done?  Is there funding to rebuild, or to build anew, for more testing?

 - Ed Kyle 
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Elmar Moelzer on 11/14/2013 02:37 pm
So what's next.  Is Dream Chaser done?  Is there funding to rebuild, or to build anew, for more testing?

 - Ed Kyle
No worries, they are good. DC can be repaired and they will continue their tests.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: BrightLight on 11/14/2013 02:45 pm
So what's next.  Is Dream Chaser done?  Is there funding to rebuild, or to build anew, for more testing?

 - Ed Kyle
No worries, they are good. DC can be repaired and they will continue their tests.
I certainly like what you said but,
How do you know this?
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Elmar Moelzer on 11/14/2013 04:00 pm
From what I remember SNC stated as much. Also, they are a pretty well standing corporation. They have the money to rebuild, if they want to.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: VDD1991 on 11/14/2013 06:50 pm
Like the X-37 and X-20, the Dream Chaser is designed to be propelled into orbit by the upper stage of a carrier rocket, but I'm curious to see how Dream Chaser compares with the X-37 and X-20 in terms of length, weight, and rocket thrust capacity. Would the Dream Chaser weigh as much as the X-37 with or without any crewmen on board?
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: adrianwyard on 11/14/2013 07:03 pm
Dream Chaser is roughly twice as heavy as both X-20 and X-37, coming in at ~10mT.

http://www.astronautix.com/craft/dynasoar.htm
http://en.wikipedia.org/wiki/X-20

http://en.wikipedia.org/wiki/X-37
http://www.astronautix.com/craft/x37.htm

http://en.wikipedia.org/wiki/Dream_Chaser
http://www.astronautix.com/craft/drehaser.htm

Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: wjbarnett on 11/14/2013 11:49 pm
No new video from the drop test, but lots of video from the prior captive carry test (starts at 6:20):
http://watch.discoverychannel.ca/daily-planet/november-2013/daily-planet---november-13th-2013/#clip1043422
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: adrianwyard on 11/15/2013 12:07 am
Interesting little detail in that video: the Dream Chaser ETA weighs 6.3mT, so quite a bit less than what's expected for the operational vehicle.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Lurker Steve on 11/15/2013 12:15 am
No engines, no fuel for the hybrids, empty cabin other than the fuzzy dice (no couches, ECLSS, etc)
Even if they did have the real TPS shell on the outside, just those items would add a bit of weight.
 
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Khadgars on 12/04/2013 01:11 am
Didn't see this posted anywhere so thought I would share it

http://www.4-traders.com/OHB-TECHNOLOGY-AG-450142/news/OHB-Technology-AG--Contract-signed-with-DLR-for-the-study-phase-for-the-utilization-of-US-company-17459911/

The gist is some European organizations are putting some money into studying the utilization of Dream Chaser as both a manned and unmanned orbital vehicle.  That has to be encouraging news for SNC.  Makes a lot of sense on the European side especially if they launch it on an Ariane.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Prober on 12/14/2013 02:07 am
Dream Chaser makes this Russian video @ 7:49
http://youtu.be/inPXDmqiM3s (http://youtu.be/inPXDmqiM3s)

https://www.youtube.com/watch?v=inPXDmqiM3s&feature=em-subs_digest-vrecs (https://www.youtube.com/watch?v=inPXDmqiM3s&feature=em-subs_digest-vrecs)
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: llanitedave on 12/14/2013 04:49 am
I'd love to see Dream Chaser on Ariane, or Proton, or Atlas, or Falcon9, or anything else.

BTW, off topic, but it was interesting to see Buran on Energia being processed horizontally
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: PeterAlt on 12/17/2013 08:40 pm
Didn't see this posted anywhere so thought I would share it

http://www.4-traders.com/OHB-TECHNOLOGY-AG-450142/news/OHB-Technology-AG--Contract-signed-with-DLR-for-the-study-phase-for-the-utilization-of-US-company-17459911/ (http://www.4-traders.com/OHB-TECHNOLOGY-AG-450142/news/OHB-Technology-AG--Contract-signed-with-DLR-for-the-study-phase-for-the-utilization-of-US-company-17459911/)

The gist is some European organizations are putting some money into studying the utilization of Dream Chaser as both a manned and unmanned orbital vehicle.  That has to be encouraging news for SNC.  Makes a lot of sense on the European side especially if they launch it on an Ariane.


The article says the German Space Agency is considering using it for Europe to send supplies and crews to the ISS. Now, ESA's barter with NASA for the SLS Service Module fulfills the obligations for Europe towards contributing its share, correct?
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Robotbeat on 12/17/2013 09:21 pm
Orion service module, not SLS service module.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: simpl simon on 12/17/2013 09:51 pm
The ESA MPCV Service Module only fulfils European obligations towards ISS Common System Operating Costs up to 2020.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: woods170 on 12/18/2013 08:51 am
The ESA MPCV Service Module only fulfils European obligations towards ISS Common System Operating Costs up to 2020.
Yes, that's for the development and initial two flight-worthy ESM's. But a deal for continued supply of ESM's is in work between NASA and ESA. And this deal is (also) specifically targeting bartering for any post-2020 ISS use by ESA. Nothing official yet, as extension of ISS beyond 2020 is not a done deal yet. The ISS partners are still in negotiations over the extension to 2028.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: PeterAlt on 12/20/2013 05:34 am
The ESA MPCV Service Module only fulfils European obligations towards ISS Common System Operating Costs up to 2020.
Yes, that's for the development and initial two flight-worthy ESM's. But a deal for continued supply of ESM's is in work between NASA and ESA. And this deal is (also) specifically targeting bartering for any post-2020 ISS use by ESA. Nothing official yet, as extension of ISS beyond 2020 is not a done deal yet. The ISS partners are still in negotiations over the extension to 2028.


Thanks!
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: JAFO on 01/09/2014 01:54 am
Got an email from a French pilot/aviation geek friend of mine, says if SNC cooperates with ESA it's the kiss of death due to French burrocracy leeching the life from anything it touches. I'm hoping it's a kiss of life and DC will be a cousin of Hermes. Time will tell.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: woods170 on 01/09/2014 11:23 am
Quote from: woods170
ESA is spreading it's eggs over multiple baskets. Risk reduction. Soyuz for ISS flights.

ESA pays for Soyuz flights with their own developments (Columbus, ATV, Orion SM).
Perhaps I wasn't clear. What I mean is this: ESA might be interested in having more options for transportation to space than just Soyuz alone. Helping DreamChaser go forward to an operational system is all about risk reduction and keeping your eggs (ESA interests in space) out of a single basket.
ESA historically had access to two different systems for flying their astro's to space (note: space, not necessarily ISS alone). Those being STS and Soyuz. STS went away, and now everything depends on Soyuz. DreamChaser might - some years from now - provide redundancy again.

Quote from: woods170
Actually, it is more likely that ESA will want to have orbital access for non-ISS missions.

Manned access? I believe it when I see it. More likely ESA will cooperate with NASA on BEO missions. For some of the robotic missions mentioned in the article ESA is funding a small X-37-like vehicle that fits on Vega.
Yes, both manned and unmanned access. My speculation is this: Eventually, the ISS wil go away. And the coop with NASA on BEO missions is not gonna cut it to keep the Euronauts at work. Post-ISS there will likely be at least some space station (be that Russian and/or commercial) and ESA will be interested in going there for fundamental research in LEO. DreamChaser could take them there.
But, don't read to much into it. The deal as announced yesterday is about some very early stage: studies. Everything beyond that point is pure speculation.

Quote from: woods170
And I don't think SN will be building DC's for ESA. It very much more likely will be that ESA will be buying DC flight services.

Which is almost the same thing.
No it is not. That's the 'own' versus 'rent' discussion all over again. I'm not going there again as it has been discussed to death over other vehicles in other threads.


This probably belongs in the discussion thread...
Correct. Have taken it here.

Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Oli on 01/09/2014 12:14 pm
Quote from: woods170
STS went away, and now everything depends on Soyuz. DreamChaser might - some years from now - provide redundancy again.

NASA and whoever wins commercial crew can provide that redundancy. The difference is ESA can pay NASA with hardware and not with money.

Quote from: woods170
But, don't read to much into it.

Well I don't.

But we could speculate what it means for Dreamchaser. Either it means DC will not win commercial crew and thus SNC is looking for alternative financing. Or DC is likely to win and ESA is looking for a way to contribute.

Or it means nothing ;).
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Jcc on 01/10/2014 12:44 am
My take on it is this: it's a very smart move for ESA to partner on Dreamchaser, even in the limited way they are doing at first, because
1. They want to help SNC win a Commercial Crew spot, if not sole winner, then one of two.
2.  That way, they have an option to fly their astronauts on it to ISS, which is desirable because
3. Whether a lifting body has technical advantages or not, it looks way cooler than a capsule, and
4. ESA astronauts riding on it will help sell their space program to the European public,
5. Especially if they can say that it was developed partly with European technology
6. Besides, they will have the option to invest further to fly it on Ariane for non-ISS missions if they choose.

A winner all around, as long as SNC does win a Commercial Crew spot, if not they will not have spent much, so no big loss.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: dror on 01/10/2014 02:00 pm
Mounts soapbox…

Well we’re hearing talk of Dream Chaser might not make the cut. So why don't they offer the service/vehicle to ESA? DC is launch vehicle agnostic so why not Ariane V or Soyuz. This bird deserves to fly, if the powers that be in the U.S. don’t appreciate it then offer it up internationally. She has waited 20 plus years from her first iteration, long enough I think…

Steps off…

Way to go Rocket  Science for your great observation made more than a year ago!
 :)
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: IRobot on 01/10/2014 03:04 pm
My take on it is this: it's a very smart move for ESA to partner on Dreamchaser, even in the limited way they are doing at first, because
1. They want to help SNC win a Commercial Crew spot, if not sole winner, then one of two.
2.  That way, they have an option to fly their astronauts on it to ISS, which is desirable because
3. Whether a lifting body has technical advantages or not, it looks way cooler than a capsule, and
4. ESA astronauts riding on it will help sell their space program to the European public,
5. Especially if they can say that it was developed partly with European technology
6. Besides, they will have the option to invest further to fly it on Ariane for non-ISS missions if they choose.

A winner all around, as long as SNC does win a Commercial Crew spot, if not they will not have spent much, so no big loss.

Don't forget: it will keep Dream Chaser afloat if NASA drops them from CCicap, possibly putting more pressure on SpaceX for a (possible) future non ISS crew service, for example Bigelow.

If ESA starts a strategy of confrontation against SpaceX (as many corporations do against each other) it means it will try to fight SpaceX in as many different markets as possible, even if losing money in some projects.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: aga on 01/10/2014 03:38 pm
If ESA starts a strategy of confrontation against SpaceX (as many corporations do against each other) it means it will try to fight SpaceX in as many different markets as possible, even if losing money in some projects.

just curious...
why would esa do this? i can imagine arianespace doing this... but esa?
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: adrianwyard on 01/10/2014 03:45 pm
Don't forget: it will keep Dream Chaser afloat if NASA drops them from CCicap, possibly putting more pressure on SpaceX for a (possible) future non ISS crew service, for example Bigelow.

If ESA starts a strategy of confrontation against SpaceX (as many corporations do against each other) it means it will try to fight SpaceX in as many different markets as possible, even if losing money in some projects.
To date all that's been exchanged are optimistic words, i.e. no hard currency.

And of course talk is cheap. I agree with JCC that strategically it is smart for both parties to publicize this conversation now. I am not sure if ESA ever had in mind to upgrade their Soyuz launch facilities for ESA manned flights, but negotiations with the Russians would be improved if they had an alternate supplier in SNC.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Lobo on 01/10/2014 04:11 pm
If ESA starts a strategy of confrontation against SpaceX (as many corporations do against each other) it means it will try to fight SpaceX in as many different markets as possible, even if losing money in some projects.

just curious...
why would esa do this? i can imagine arianespace doing this... but esa?

Isn't ArianeSpace government subsidized through the member nations of the ESA?  Or some of them anyway?  I don't know that the two are completely separate entities.

But, the ESA could "buy" a Dream Chaser or two and base them in Guiana, and launch them on Ariane 5 themselves, and have them return there for reprocessing and restacking.   That's something they can't really do with an expendable capsule that they depend on the maufacturer for every launch.  A fully reusable vehicle could be "owned" by them and launched by them, with spare parts and technical assistance provided by SNC.

It might not be an ideal situation for SNC as they probably would be leary of a customer being able to have actual possession of a DC.  But...if they get dropped from CCiCAP, it could be any port in a storm, and a way to take DC to actual flight.   And ESA would get DC at a song because NASA will have paid for most of it's development. 
And if DC is designed to launch on Atlas V or other similar LV's, I doubt it'll change the aerodynamics enough of Ariane 5 that it couldn't mount an adaptor and put DC right on top.  Although that's something to would want to look at and verify, obviously.



Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: adrianwyard on 01/10/2014 05:42 pm
Flight Global article that references ESA's IXV and PRIDE projects.

IXV is scheduled to fly in October which would verify the TPS were DC to switch from their current plan. I wonder if funds that the PRIDE program (IXV follow-on) had hoped to get might be rerouted to the SNC collaboration.

http://www.flightglobal.com/news/articles/europe-chases-dream-of-spaceplane-operations-394705/
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Jcc on 01/11/2014 12:21 pm
One of the criteria used by NASA to select both COTS and Commercial Crew vendors is a viable business case and financial security. The business case it greatly helped by having non-NASA customers, which up to now was either Bigalow or the idea of doing space tourism independently, both of which are less secure than a major government program. The business case is also helped by having low cost, where SpaceX presumably has an advantage, but that can be trumped by having a guaranteed market for non-NASA flights. Of course the decision to extend the ISS to 2014 also helps greatly. That may make it possible to select 2 vendors, rather than having to down select to 1.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Rocket Science on 01/11/2014 12:24 pm
Mounts soapbox…

Well we’re hearing talk of Dream Chaser might not make the cut. So why don't they offer the service/vehicle to ESA? DC is launch vehicle agnostic so why not Ariane V or Soyuz. This bird deserves to fly, if the powers that be in the U.S. don’t appreciate it then offer it up internationally. She has waited 20 plus years from her first iteration, long enough I think…

Steps off…

Way to go Rocket  Science for your great observation made more than a year ago!
 :)
Thanks for the kind words but I just put myself in the position of Mark Sirangelo at SNC and always having a back-up plan and look at all the possibilities. Sometimes Americans tend to think that the U.S. = “the world” much to the nation’s expense in being too isolationist.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: dror on 01/17/2014 07:18 am
From the first time I heard of dream chaser I was wandering if it was possible to design it to include the seconed stage as part of the ship, for reusability resons. Not as big as a shutle orbiter, but not only as a third stage. That could have saved a lot of money per launch.
The reduced performance by the extra heat shields may even out by canceling the hybrid engines with their lesser Isp.
The rear docking port will be moved to the roof entrance.
Could this work?
I guess not, but I would love to hear why not.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Todd Martin on 01/17/2014 03:02 pm
Another great article by Chris.  I'm most intrigued by "Details of the downselect are sketchy, although it is understood one or two companies are likely to lose out on NASA funding. A potential scenario that has been put forward by sources claims two providers may survive, one at full funding, another with half funding – the “1.5″ scenario. It has also been suggested that SpaceX and SNC are classed as the front runners."

This reminds me of Mark Sirangelo quoting Gandhi:  "First they ignore you, then they laugh at you, then they fight you, then you win."

So many people have doubted the chance of DC ever becoming operational.  I think they failed to fully appreciate SNC's dedication to DC and the desire of NASA employees (especially current and former pilot astronauts) to have a winged spacecraft.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Rocket Science on 01/17/2014 11:16 pm
From the first time I heard of dream chaser I was wandering if it was possible to design it to include the seconed stage as part of the ship, for reusability resons. Not as big as a shutle orbiter, but not only as a third stage. That could have saved a lot of money per launch.
The reduced performance by the extra heat shields may even out by canceling the hybrid engines with their lesser Isp.
The rear docking port will be moved to the roof entrance.
Could this work?
I guess not, but I would love to hear why not.
It would no longer be Dream Chaser but something the size of Hermes...
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: TrevorMonty on 01/18/2014 09:58 pm
From my understanding DC project was started well before commercial crew program. The CC just help give it a boost.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: RonM on 01/18/2014 10:15 pm
From the first time I heard of dream chaser I was wandering if it was possible to design it to include the seconed stage as part of the ship, for reusability resons. Not as big as a shutle orbiter, but not only as a third stage. That could have saved a lot of money per launch.
The reduced performance by the extra heat shields may even out by canceling the hybrid engines with their lesser Isp.
The rear docking port will be moved to the roof entrance.
Could this work?
I guess not, but I would love to hear why not.
It would no longer be Dream Chaser but something the size of Hermes...

Too much extra mass and cost to make it aerodynamic and able to survive reentry. It's cheaper to toss the second stage.

Best bet is to wait until someone makes a fully reusable rocket big enough to haul a DC to orbit. A F9R with a reusable second stage wouldn't be able to do it.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Elmar Moelzer on 01/18/2014 11:11 pm
Well, there were plans for a larger version of the HL-20 that the DreamChaser is based on. So might not completely impossible, just unlikely.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: docmordrid on 01/19/2014 06:08 am
That would be HL-42,

https://www.google.com/url?sa=t&source=web&rct=j&ei=53jbUs3LLMjdoATVmYDQBw&url=http://forum.nasaspaceflight.com/index.php%3Faction%3Ddlattach%3Btopic%3D32078.0%3Battach%3D525884&cd=10&ved=0CEQQFjAJ&usg=AFQjCNGansyMij4F93lQaNOPy9nCz_BVRQ&sig2=PJzI73roTfqfgr9ZJiszXA
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Elmar Moelzer on 01/19/2014 06:12 pm
That would be HL-42,

https://www.google.com/url?sa=t&source=web&rct=j&ei=53jbUs3LLMjdoATVmYDQBw&url=http://forum.nasaspaceflight.com/index.php%3Faction%3Ddlattach%3Btopic%3D32078.0%3Battach%3D525884&cd=10&ved=0CEQQFjAJ&usg=AFQjCNGansyMij4F93lQaNOPy9nCz_BVRQ&sig2=PJzI73roTfqfgr9ZJiszXA
That's the one!
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Michael Z Freeman on 01/19/2014 09:16 pm
I made a montage image of Dream Chaser history / context ...

Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Lars_J on 01/19/2014 10:52 pm
Nice, but dynasoar doesn't have much to do with DC.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Michael Z Freeman on 01/20/2014 11:54 am
Nice, ...

Thanks !  :)

Quote
but dynasoar doesn't have much to do with DC.

Why do you say that ? The historical influences are well known. The Boeing X-20 Dyna-Soar projec (http://en.wikipedia.org/wiki/X-20_Dyna-Soar)t is part of space plane history along with the "X" test pilots program.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Rocket Science on 01/21/2014 12:14 am
That would be HL-42,

https://www.google.com/url?sa=t&source=web&rct=j&ei=53jbUs3LLMjdoATVmYDQBw&url=http://forum.nasaspaceflight.com/index.php%3Faction%3Ddlattach%3Btopic%3D32078.0%3Battach%3D525884&cd=10&ved=0CEQQFjAJ&usg=AFQjCNGansyMij4F93lQaNOPy9nCz_BVRQ&sig2=PJzI73roTfqfgr9ZJiszXA
While I really appreciate Giuseppe’s artwork; I respectfully disagree with the history of Dream Chaser and the HL-20 directly descending from the BOR-4 which has a totally different moldine.  DC is closer in aerodynamics to the PRIME/X-23 and the later X-24A/X-38 and the concept all began with the Martin Yellow Bird space taxi...
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: raketen on 01/21/2014 12:57 am
Starting in 1983, the Vehicle Analysis Branch (NASA Langley Research Center) investigated the BOR-4 small spaceplane orbited several times by the Soviets starting in 1982 and recovered in the Indian Ocean and Black Sea. During recovery operations of the BOR-4 in the Indian Ocean, an Australian P-3 Orion aircraft was able to take photographs of the vehicle floating in the water and being hauled aboard the recovery ship. Based on these photos and subsequent analysis, small wind tunnels models were produced and tested in the NASA Langley wind tunnels. Later, a full-scale mockup of the HL-20 was built, again based on the BOR-4 photo analysis and wind tunnel model moldlines.  Eventually this mockup would be obtained by Sierra Nevada along with the wind tunnel data to form the basis of Dreamchaser.  Giuseppe's work is an accurate description of the direct link between BOR-4, HL-20 and Dreamchaser. 
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Rocket Science on 01/21/2014 01:30 am
Starting in 1983, the Vehicle Analysis Branch (NASA Langley Research Center) investigated the BOR-4 small spaceplane orbited several times by the Soviets starting in 1982 and recovered in the Indian Ocean and Black Sea. During recovery operations of the BOR-4 in the Indian Ocean, an Australian P-3 Orion aircraft was able to take photographs of the vehicle floating in the water and being hauled aboard the recovery ship. Based on these photos and subsequent analysis, small wind tunnels models were produced and tested in the NASA Langley wind tunnels. Later, a full-scale mockup of the HL-20 was built, again based on the BOR-4 photo analysis and wind tunnel model moldlines.  Eventually this mockup would be obtained by Sierra Nevada along with the wind tunnel data to form the basis of Dreamchaser.  Giuseppe's work is an accurate description of the direct link between BOR-4, HL-20 and Dreamchaser.

Great, repeating half the story doesn’t make it the full story. The Soviets based their work on the U.S. program 20 years prior...  The USSR put a different cockpit/windscreen screen on a PRIME /X-23... All the U.S. did was to resurrect the space taxi concept upon seeing BOR as the HL-20 which got its name from being 20% larger than the HL-10. By superficial logic then Buran is an exact copy of the Shuttle, which it was not...

http://forum.nasaspaceflight.com/index.php?topic=27178.0

Edit:typo
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: GClark on 01/21/2014 05:58 am
While I really appreciate Giuseppe’s artwork; I respectfully disagree with the history of Dream Chaser and the HL-20 directly descending from the BOR-4 which has a totally different moldine.  DC is closer in aerodynamics to the PRIME/X-23 and the later X-24A/X-38 and the concept all began with the Martin Yellow Bird space taxi...

IMNSHO the Yellow Bird represents an intermediate design in Martins' (Multhopp) evolution of the Aerospace A3-4 to the SV-5 (See Hallion, The Hypersonic Revolution, Vol 1, Case 5).


Great, repeating half the story doesn’t make it the full story. The Soviets based their work on the U.S. program 20 years prior...  The USSR put a different cockpit/windscreen screen on a PRIME /X-23... All the U.S. did was to resurrect the space taxi concept upon see BOR as the HL-20 which got its name from being 20% larger than the HL-10. By superficial logic then Buran is an exact copy of the Shuttle, which it was not...

http://forum.nasaspaceflight.com/index.php?topic=27178.0

I am going to respectfully request a citation to back that one up.

IIRC Mikoyan (Lozino-Lozinsky) developed the BOR from the Tsybin PKA & Chelomei Raketoplan designs (See Anatoly Zak).  I have yet to read anything claiming US lifting body influence on these designs.  If you have some evidence, please show (Yes, I am from Missouri).

I see parallel but unrelated development of similar designs a la the whole GE Apollo vs Soyuz thing.  I could be wrong.

Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Rocket Science on 01/21/2014 01:24 pm
While I really appreciate Giuseppe’s artwork; I respectfully disagree with the history of Dream Chaser and the HL-20 directly descending from the BOR-4 which has a totally different moldine.  DC is closer in aerodynamics to the PRIME/X-23 and the later X-24A/X-38 and the concept all began with the Martin Yellow Bird space taxi...

IMNSHO the Yellow Bird represents an intermediate design in Martins' (Multhopp) evolution of the Aerospace A3-4 to the SV-5 (See Hallion, The Hypersonic Revolution, Vol 1, Case 5).


Great, repeating half the story doesn’t make it the full story. The Soviets based their work on the U.S. program 20 years prior...  The USSR put a different cockpit/windscreen screen on a PRIME /X-23... All the U.S. did was to resurrect the space taxi concept upon see BOR as the HL-20 which got its name from being 20% larger than the HL-10. By superficial logic then Buran is an exact copy of the Shuttle, which it was not...

http://forum.nasaspaceflight.com/index.php?topic=27178.0

I am going to respectfully request a citation to back that one up.

IIRC Mikoyan (Lozino-Lozinsky) developed the BOR from the Tsybin PKA & Chelomei Raketoplan designs (See Anatoly Zak).  I have yet to read anything claiming US lifting body influence on these designs.  If you have some evidence, please show (Yes, I am from Missouri).

I see parallel but unrelated development of similar designs a la the whole GE Apollo vs Soyuz thing.  I could be wrong.
All that I can find preceding BOR was Spiral/Mig-105 (bast shoe) that has been made public from USSR, and that was a folding wing design, a different moldline, and not a true lifting body for its full flight envelope. (That is what Giuseppe presents). The SV-5/PRIME/X-23 are all the same family (flew suborbital well before BOR) and the SV-5J is the jet powered X-24A on display in Ohio converted back again into a X-24A facsimile. If the Russians can prove their creation of the lifting body program then they never made it public and the late Dale Reed would beg to differ I’m sure... Citation Me...

For those interested; there is/was a SV-5 mockup on display hanging from the ceiling at the U.S. Space and Missile Museum at Canaveral.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Elmar Moelzer on 01/21/2014 03:16 pm
I always thought that Spiral was the manned orbital space plane that was meant to be final result of the BOR test program. IIRC, BOR6 was the final BOR and that looked very similar to the DC.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: raketen on 01/21/2014 03:30 pm
I will let others argue the derivation of BOR-4 from preceding designs (U.S or Soviet).  The fact is the HL-20 moldline was derived directly from the Soviet orbital vehicle BOR-4.  Originally, the Langley design was put forth as a possible Assured Crew Return Vehicle (ACRV) from the space station.  Later it was called STAR for Space Taxi and Return Vehicle.  Someone in charge at Langley Research Center said, with tongue in cheek, that it should be called the HL-20 because "it was twice as good as the HL-10".  The name stuck.  It had nothing to do with the size relative to HL-10.  However, when a design called the HL-42 was proposed, it was because it would be 42% larger than the HL-20.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Rocket Science on 01/21/2014 04:04 pm
I will let others argue the derivation of BOR-4 from preceding designs (U.S or Soviet).  The fact is the HL-20 moldline was derived directly from the Soviet orbital vehicle BOR-4.  Originally, the Langley design was put forth as a possible Assured Crew Return Vehicle (ACRV) from the space station.  Later it was called STAR for Space Taxi and Return Vehicle.  Someone in charge at Langley Research Center said, with tongue in cheek, that it should be called the HL-20 because "it was twice as good as the HL-10".  The name stuck.  It had nothing to do with the size relative to HL-10.  However, when a design called the HL-42 was proposed, it was because it would be 42% larger than the HL-20.
The mock-up model that Langley tested was closer to the BOR-6.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: raketen on 01/21/2014 05:02 pm
I don't read Russian, but the following reference show another view of BOR-6 with variable dihedral wings (as a variant of BOR-4??).

http://www.buran.ru/htm/bors.htm#bor-7

But it was the Australian P-3A photos of the BOR-4 that were used to design the original HL-20 wind tunnel models.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Rocket Science on 01/21/2014 05:18 pm
Langley actually tested mutiple variants of the HL-20 including different camber, tails and canard, don't get fixated on the single BOR like design. The way I see it the Soviets ripped-off an American concept and the Americans ripped-off their evolution back and now we have Dream Chaser. Lots of good reading, enjoy!

http://www.ninfinger.org/models/vault2008/HL-20/HL-20%20MODEL.pdf
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Ronsmytheiii on 01/21/2014 09:05 pm
So reading way between the lines, while DC will most definitely use an OPF:

Quote

    Mark Sirangelo, corporate vice president and head of SNC’s Space Systems, will make the announcements and be joined by:

    -- Bob Cabana, Kennedy Space Center director
    -- Michael Gass, United Launch Alliance president and CEO
    -- Frank DiBello, Space Florida president and CEO
    -- Larry Price, Lockheed Martin Space Systems deputy program manager for NASA's Orion spacecraft
    -- Steve Lindsey, Sierra Nevada Corporation Dream Chaser program manager

Does this mean DC might also or instead use MPCV processing facilities such as the O&C high bay or the MPPF? Of course LM is a DC supplier, but they must have some larger role in DC processing to be at this presser.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Jim on 01/21/2014 09:26 pm

Does this mean DC might also or instead use MPCV processing facilities such as the O&C high bay or the MPPF? Of course LM is a DC supplier, but they must have some larger role in DC processing to be at this presser.

MPPF is NASA's.   The O&C is Orion's.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Ronsmytheiii on 01/22/2014 10:04 pm

Does this mean DC might also or instead use MPCV processing facilities such as the O&C high bay or the MPPF? Of course LM is a DC supplier, but they must have some larger role in DC processing to be at this presser.

MPPF is NASA's.   The O&C is Orion's.

Thanks Jim, the only reason I thought that it might be possible was due to LM's role as subsystem supplier for SNC and the possibility that the MPCV and DC shared a few systems as a result.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Rocket Science on 01/22/2014 10:27 pm
I find it historically interesting with the upcoming announcement tomorrow and that Lockheed Martin will be represented as part of Dream Chasers Program. Martin constructed the conceptual Space Taxi Yellowbird, the successful lifting body series:  SV-5/PRIME, X-24A/B and is constructing the Dream Chaser OTV. 50 years later and now we are coming full circle...Pretty neat that... 8)
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Lars_J on 01/23/2014 07:43 pm
It's wonderful to read about the DC 2016 flight announcement, but one of the slides shown gives me pause: (attached below)

Is it just me or is it starting to look a lot like one of the Orion "here's where the money is spent" map of contractors/subcontractors/partners that has appeared in other NASA presentations?
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: butters on 01/23/2014 07:56 pm
It's wonderful to read about the DC 2016 flight announcement, but one of the slides shown gives me pause: (attached below)

Is it just me or is it starting to look a lot like one of the Orion "here's where the money is spent" map of contractors/subcontractors/partners that has appeared in other NASA presentations?

That's what you get when you work with Lockheed: charts about the breadth of their supply chain, designed by lobbyists, for politicians. The merit of a project is measured by the political inexpedience of cancelling it.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: newpylong on 01/23/2014 07:59 pm
Nice theory but who cares? They are good at what they do.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Go4TLI on 01/23/2014 08:01 pm
It's wonderful to read about the DC 2016 flight announcement, but one of the slides shown gives me pause: (attached below)

Is it just me or is it starting to look a lot like one of the Orion "here's where the money is spent" map of contractors/subcontractors/partners that has appeared in other NASA presentations?

That's what you get when you work with Lockheed: charts about the breadth of their supply chain, designed by lobbyists, for politicians. The merit of a project is measured by the political inexpedience of cancelling it.

Ridiculous comments.  Always a conspiracy unless it's SpaceX.  I see even the haters need to go after commercial efforts now.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: dcporter on 01/23/2014 08:01 pm
It's unfortunately a game that many companies in many industries have found it important to play.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Lars_J on 01/23/2014 08:01 pm
Nice theory but who cares? They are good at what they do.

Yes they are. My concern is more about the operational cost of the program with so many partners/contractors/subcontractors involved.

----

Was there any question during the press conference about the status of the DEC (duel engine Centaur) for Atlas V? Because I believe that is needed for both DC and CST-100.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: veblen on 01/23/2014 08:17 pm
It's wonderful to read about the DC 2016 flight announcement, but one of the slides shown gives me pause: (attached below)

Is it just me or is it starting to look a lot like one of the Orion "here's where the money is spent" map of contractors/subcontractors/partners that has appeared in other NASA presentations?

That's what you get when you work with Lockheed: charts about the breadth of their supply chain, designed by lobbyists, for politicians. The merit of a project is measured by the political inexpedience of cancelling it.

Ridiculous comments.  Always a conspiracy unless it's SpaceX.  I see even the haters need to go after commercial efforts now.


I was enjoying the images of DC and Shuttle, nice, but of course it couldn't last, could it?
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: JBF on 01/23/2014 08:21 pm
It's wonderful to read about the DC 2016 flight announcement, but one of the slides shown gives me pause: (attached below)

Is it just me or is it starting to look a lot like one of the Orion "here's where the money is spent" map of contractors/subcontractors/partners that has appeared in other NASA presentations?

That's what you get when you work with Lockheed: charts about the breadth of their supply chain, designed by lobbyists, for politicians. The merit of a project is measured by the political inexpedience of cancelling it.

Ridiculous comments.  Always a conspiracy unless it's SpaceX.  I see even the haters need to go after commercial efforts now.

Why is it ridiculous? It's SOP with military contractors.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: veblen on 01/23/2014 08:31 pm
How long before non SpaceX space industry workers have to wear a scarlett "G"? Maybe we can start a new poll.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: butters on 01/23/2014 08:48 pm
It's wonderful to read about the DC 2016 flight announcement, but one of the slides shown gives me pause: (attached below)

Is it just me or is it starting to look a lot like one of the Orion "here's where the money is spent" map of contractors/subcontractors/partners that has appeared in other NASA presentations?

That's what you get when you work with Lockheed: charts about the breadth of their supply chain, designed by lobbyists, for politicians. The merit of a project is measured by the political inexpedience of cancelling it.

Ridiculous comments.  Always a conspiracy unless it's SpaceX.  I see even the haters need to go after commercial efforts now.

It's no conspiracy. It's just the nature of government contracting and its associated incentive structures. Clearly it affects both commercial and traditional contracts. It's a game they play, and like all games, it exists because of the rules. It's unproductive to hate the players for playing the game. It's more productive to call into the question the rules of the game and the game itself.

We can't expect most players to prioritize their own values ahead of moves which seem to be favored by the rules of the game. But sometimes they do, because humans aren't always rational, because we are sometimes inclined to believe that we have a new and better understanding than others who came before us, and because we don't always agree on how to discount the value of outcomes at increasing distant futures.

In a sense, the exception proves the rule. Obviously, one player is playing the game differently from the others, and the difference between the other commercial and traditional players is comparatively small.

Dream Chaser and Orion are both built on sprawling horizontally-integrated supply chains. So is CST-100. There's no reason to conclude that commercial is any different than traditional in this respect, and there's no reason why I should "hate" the game any differently when it is played in basically the same way by different players.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Lar on 01/23/2014 08:53 pm
Please keep this thread on topic, and let's not bash SpaceX, Orion, SLS, SpaceX bashers, Orion bashers, SLS bashers, mods, people who like clowns, mod bashers, or anyone else either... thanks

Thanks to Chris for some superb updates
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: butters on 01/23/2014 09:01 pm
So the big question from the press conference is the status of the Dual Engine Centaur with respect to the maiden DC launch on Atlas V. I think we can safely assume that any LAS testing will be deferred until after the first unmanned launch(es).
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Lurker Steve on 01/23/2014 09:04 pm
So the big question from the press conference is the status of the Dual Engine Centaur with respect to the maiden DC launch on Atlas V. I think we can safely assume that any LAS testing will be deferred until after the first unmanned launch(es).

I don't know the exact status, but that milestone is listed on Boeing's CST-100 CCiCAP list.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: BrightLight on 01/23/2014 09:04 pm
Where did SNC get the funds to buy an Atlas V and dual Centaur?
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: arachnitect on 01/23/2014 09:09 pm
Where is the money coming from? Is SNC really betting the farm on this?
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Go4TLI on 01/23/2014 09:12 pm
Where did SNC get the funds to buy an Atlas V and dual Centaur?

They won't say, which is perfectly their right. 

However, it very well could be internal funding.  They are obviously committed to this vehicle, and with it's variants included, see a reasonable case to commit corporate capital and accept that risk for a greater return down the road. 

All in all this is a GREAT thing and, at least for me, was not expected today.  Big props to SNC because I think they just changed the game.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: BrightLight on 01/23/2014 09:15 pm
Where did SNC get the funds to buy an Atlas V and dual Centaur?

They won't say, which is perfectly their right. 

However, it very well could be internal funding.  They are obviously committed to this vehicle, and with it's variants included, see a reasonable case to commit corporate capital and accept that risk for a greater return down the road. 

All in all this is a GREAT thing and, at least for me, was not expected today.  Big props to SNC because I think they just changed the game.
I hope that this level of commitment from SNC helps there cause, few aerospace company's would put this much skin in the game - it would be interesting to see there business model, I get the feeling it would be an eye-opener, not quite as good as SpeceX but it must be plush.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Elmar Moelzer on 01/23/2014 09:19 pm
Where is the money coming from? Is SNC really betting the farm on this?
I guess they have enough profit from their many other projects to cover the investment. The flight is still more than two years out, which helps. SNC is a big company.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Go4TLI on 01/23/2014 09:20 pm
Where did SNC get the funds to buy an Atlas V and dual Centaur?

They won't say, which is perfectly their right. 

However, it very well could be internal funding.  They are obviously committed to this vehicle, and with it's variants included, see a reasonable case to commit corporate capital and accept that risk for a greater return down the road. 

All in all this is a GREAT thing and, at least for me, was not expected today.  Big props to SNC because I think they just changed the game.
I hope that this level of commitment from SNC helps there cause, few aerospace company's would put this much skin in the game - it would be interesting to see there business model, I get the feeling it would be an eye-opener, not quite as good as SpeceX but it must be plush.

ALL aerospace companies have skin in the game.  It just varies depending on the product and what the company expects for a market.  As an example, where do you think Boeing gets the money when developing a new airplane?  It's all internal and it is done because they expect a much larger return on investment. 

I have no idea how you can even comfortably speculate that SNC's business model is somehow inferior to SpaceX.  You have no data to support that only gushing emotions about SpaceX.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Lurker Steve on 01/23/2014 09:45 pm
So the big question from the press conference is the status of the Dual Engine Centaur with respect to the maiden DC launch on Atlas V. I think we can safely assume that any LAS testing will be deferred until after the first unmanned launch(es).

Was there anything mentioned in the press conference about the crew access tower, or mods to the pad to support commercial crew ?
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: butters on 01/23/2014 10:02 pm
So the big question from the press conference is the status of the Dual Engine Centaur with respect to the maiden DC launch on Atlas V. I think we can safely assume that any LAS testing will be deferred until after the first unmanned launch(es).

Was there anything mentioned in the press conference about the crew access tower, or mods to the pad to support commercial crew ?

I don't know, but it seems quite unlikely that ULA would interrupt operations at LC-41 to make such modifications. LC-39B might be the most likely site for any manned DC launches.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Lars_J on 01/23/2014 10:06 pm
So the big question from the press conference is the status of the Dual Engine Centaur with respect to the maiden DC launch on Atlas V. I think we can safely assume that any LAS testing will be deferred until after the first unmanned launch(es).

Was there anything mentioned in the press conference about the crew access tower, or mods to the pad to support commercial crew ?

I don't know, but it seems quite unlikely that ULA would interrupt operations at LC-41 to make such modifications. LC-39B might be the most likely site for any manned DC launches.

The mods probably won't be that much of an interruption. There have been multiple proposals from ULA about how to set up crew access at LC-41. They are planning on using LC-41.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Lars_J on 01/23/2014 10:09 pm
Where did SNC get the funds to buy an Atlas V and dual Centaur?

I don't think its paid all up front. The "downpayment" for the flight might be internally funded, but I got the impression from the recap in the update thread that the flight would likely not happen if DC was not selected for the next phase of commercial crew. So if DC is selected, then future NASA payments would pay for a significant part (or all?) of the remaining launch cost. This is as one would expect - ULA is acting as a subcontractor to SnC here.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: baldusi on 01/23/2014 10:10 pm
LC-41 uses a flat pad design, win an MLP. In the worst case, they would add a new MLP. But they dont need to. The Atlas moves to the pad fully integrated. And thus the construction would be stop for few of days per launch. It's mostly a metallic structure, anyways.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Lars_J on 01/23/2014 10:12 pm
LC-41 uses a flat pad design, win an MLP. In the worst case, they would add a new MLP. But they dont need to. The Atlas moves to the pad fully integrated. And thus the construction would be stop for few of days per launch. It's mostly a metallic structure, anyways.

The MLP would not likely require much modification (or any?). But it depends on how they want to do it. Some sort of permanent tower will be needed at the pad - where the MLP would roll up against it.

(first image from old Nasaspaceflight articles, more on L2 likely)
EDIT: Added hi-res pad image.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Lars_J on 01/23/2014 10:32 pm
Here is an older LC-41 crew access concept, that uses a modified MLP instead of a separate crew access tower. (not sure how crew escape would work)

This concept has most likely been completely replaced by the one above.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Jim on 01/23/2014 10:45 pm

Does this mean DC might also or instead use MPCV processing facilities such as the O&C high bay or the MPPF? Of course LM is a DC supplier, but they must have some larger role in DC processing to be at this presser.

MPPF is NASA's.   The O&C is Orion's.

Thanks Jim, the only reason I thought that it might be possible was due to LM's role as subsystem supplier for SNC and the possibility that the MPCV and DC shared a few systems as a result.

I was wrong.  Dream Chaser is going to space vacated by the SM going to ESA.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Paul Adams on 01/24/2014 10:04 am
http://www.bbc.co.uk/news/science-environment-25878042
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Star One on 01/24/2014 01:02 pm
Will DC be using a unique payload connector between it & the Atlas or are they adapting an existing item for it?
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Chris Bergin on 01/24/2014 02:03 pm
My article will be in an hour or so. Wanted to use the quotes, but cover the deal with some background, so it's a longish one.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: newpylong on 01/24/2014 02:16 pm
So the big question from the press conference is the status of the Dual Engine Centaur with respect to the maiden DC launch on Atlas V. I think we can safely assume that any LAS testing will be deferred until after the first unmanned launch(es).

Was there anything mentioned in the press conference about the crew access tower, or mods to the pad to support commercial crew ?

I don't know, but it seems quite unlikely that ULA would interrupt operations at LC-41 to make such modifications. LC-39B might be the most likely site for any manned DC launches.

They've stated LC-41 will be it. That is where the current GSDO designs are for. Operations will be minimally impacted. FSS that won't get in the way of the ML.

Chris ran an article on this in 2012.

If 39B ever becomes multi-use don't expect that until after the first SLS launch. Lots of pad work still.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Ben the Space Brit on 01/24/2014 02:37 pm
It should be interesting to see how close the three competing commercial crew taxis get to full operational status before the start treading on each other's toes in budgetary terms.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Michael Z Freeman on 01/24/2014 03:20 pm
So, how does this project compare to Skylon ? That has projected date of 2019 for test flights. Are Reaction Engines Limited (REL) in competition with SNC ? I'm still fairly new to this area.

EDIT: Added hi-res pad image.

Hey, been looking everywhere for that hi res version. Thanks  8) ! Is that an SNC render ?
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Robotbeat on 01/24/2014 03:23 pm
Skylon is unmanned. It is more comparable to Falcon 9 than Dreamchaser. It could take manned payloads, but that's really not what it's designed around.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Michael Z Freeman on 01/24/2014 03:31 pm
Skylon is unmanned. It is more comparable to Falcon 9 than Dreamchaser. It could take manned payloads, but that's really not what it's designed around.

OK, yes, thanks ... interesting. Of course I can't help swelling with pride at the thought of a British space plane, unmanned or not  ;)
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: TomH on 01/24/2014 03:51 pm
Wasn't there an announcement recently that they have had some preleminary talks with SpaceX about looking at F9v1.1 as a backup? I have to wonder how much they could save by using that LV, especially if SX can perfect RTLS for first stage.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: kcrick on 01/24/2014 03:58 pm
My article will be in an hour or so. Wanted to use the quotes, but cover the deal with some background, so it's a longish one.

Good article Chris!  I'm just a little confused from the article about the Block 0.5 and Block 1 as to what the ETA will be used for after each upgrade. It's not really clear to me - did they have any new news on this?
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Go4TLI on 01/24/2014 04:07 pm
My article will be in an hour or so. Wanted to use the quotes, but cover the deal with some background, so it's a longish one.

Good article Chris!  I'm just a little confused from the article about the Block 0.5 and Block 1 as to what the ETA will be used for after each upgrade. It's not really clear to me - did they have any new news on this?

It's an evolution of the ETA with incremental upgrades to bring it closer to the planned operational flight vehicle.

0.5:  Upgraded systems for uncrewed approach and landing tests
1.0:  Further upgrades and ejection seat for crewed flights. 
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Jim on 01/24/2014 04:20 pm
That is where the current GSDO designs are for.

GSDO is not involved with this
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Prober on 01/24/2014 04:30 pm
Where did SNC get the funds to buy an Atlas V and dual Centaur?

That's easy ....lots of possible ways including an Angel investor or a sweetheart deal.   Its also keep in mind its  in ULA's best interest
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Kasponaut on 01/24/2014 04:31 pm
Any idea of who will get to fly on the first manned DC flight?
Maybe Steve Lindsey as CDR? ;-)
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Go4TLI on 01/24/2014 04:36 pm
Where did SNC get the funds to buy an Atlas V and dual Centaur?

That's easy ....lots of possible ways including an Angel investor or a sweetheart deal.   Its also keep in mind its  in ULA's best interest

Why would SNC pay for a launch vehicle soley for ULA's "best interest"?  That makes zero business sense and ULA is not going to donate a launch vehicle either if that is what you were trying to imply.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Elmar Moelzer on 01/24/2014 04:39 pm
Why would SNC pay for a launch vehicle soley for ULA's "best interest"?  That makes zero business sense and ULA is not going to donate a launch vehicle either if that is what you were trying to imply.
I think he meant that it would be in ULAs best interest to help SNC out with a good deal on the launch, since a selection of SNC (and/or the CST 100) would mean lots of extra business for ULA.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Go4TLI on 01/24/2014 04:41 pm
Why would SNC pay for a launch vehicle soley for ULA's "best interest"?  That makes zero business sense and ULA is not going to donate a launch vehicle either if that is what you were trying to imply.
I think he meant that it would be in ULAs best interest to help SNC out with a good deal on the launch, since a selection of SNC (and/or the CST 100) would mean lots of extra business for ULA.

It's a contract.  And those are always negotiated.  But that doesn't mean ULA gave it away or SNC did it to prop up ULA. 
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Jim on 01/24/2014 04:47 pm
Why would SNC pay for a launch vehicle soley for ULA's "best interest"?  That makes zero business sense and ULA is not going to donate a launch vehicle either if that is what you were trying to imply.
I think he meant that it would be in ULAs best interest to help SNC out with a good deal on the launch, since a selection of SNC (and/or the CST 100) would mean lots of extra business for ULA.

It's a contract.  And those are always negotiated.  But that doesn't mean ULA gave it away or SNC did it to prop up ULA. 

And ULA can't give a better deal to others vs the US gov't
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Elmar Moelzer on 01/24/2014 04:56 pm
And ULA can't give a better deal to others vs the US gov't
Did not know that... Thanks for the info!
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Lurker Steve on 01/24/2014 05:02 pm
Why would SNC pay for a launch vehicle soley for ULA's "best interest"?  That makes zero business sense and ULA is not going to donate a launch vehicle either if that is what you were trying to imply.
I think he meant that it would be in ULAs best interest to help SNC out with a good deal on the launch, since a selection of SNC (and/or the CST 100) would mean lots of extra business for ULA.

It's a contract.  And those are always negotiated.  But that doesn't mean ULA gave it away or SNC did it to prop up ULA. 

And ULA can't give a better deal to others vs the US gov't

I assume it's booked thru LM Commercial Launch Services, right ? Is it possible to un-bundle some of those extra costs that are DOD-specific for this and other commercial flights ?

http://www.satellitetoday.com/publications/2013/12/17/lockheed-martin-to-re-enter-the-commercial-satellite-business/

This article does say that ULA was able to reduce the cost of an Atlas by over 30 percent in the last 2 years.

Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Lars_J on 01/24/2014 05:04 pm
It's an evolution of the ETA with incremental upgrades to bring it closer to the planned operational flight vehicle.

0.5:  Upgraded systems for uncrewed approach and landing tests
1.0:  Further upgrades and ejection seat for crewed flights. 

Ejection seats?!? Did I miss something, or where did that come from? I don't think I've ever seen anything to indicate that DC would ever fly with ejection seats.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Prober on 01/24/2014 05:16 pm
Where did SNC get the funds to buy an Atlas V and dual Centaur?

That's easy ....lots of possible ways including an Angel investor or a sweetheart deal.   Its also keep in mind its  in ULA's best interest

Why would SNC pay for a launch vehicle soley for ULA's "best interest"?  That makes zero business sense and ULA is not going to donate a launch vehicle either if that is what you were trying to imply.

Could give you several "possibles" to think over.  Remember ULA is in the launch business, and looking for new contracts.
Think lead times.  Also remember Boeing is also using the Atlas V with dual engine Centaur.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Go4TLI on 01/24/2014 05:17 pm
It's an evolution of the ETA with incremental upgrades to bring it closer to the planned operational flight vehicle.

0.5:  Upgraded systems for uncrewed approach and landing tests
1.0:  Further upgrades and ejection seat for crewed flights. 

Ejection seats?!? Did I miss something, or where did that come from? I don't think I've ever seen anything to indicate that DC would ever fly with ejection seats.

I cannot comment on if you missed anything or not but I didn't make it up either.  It's still an experimental vehicle under test.  Not sure why you wouldn't want to have an ejection system while performing said testing for the pilot(s).
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: yg1968 on 01/24/2014 05:19 pm
Why would SNC pay for a launch vehicle soley for ULA's "best interest"?  That makes zero business sense and ULA is not going to donate a launch vehicle either if that is what you were trying to imply.
I think he meant that it would be in ULAs best interest to help SNC out with a good deal on the launch, since a selection of SNC (and/or the CST 100) would mean lots of extra business for ULA.

It's a contract.  And those are always negotiated.  But that doesn't mean ULA gave it away or SNC did it to prop up ULA. 

And ULA can't give a better deal to others vs the US gov't

What happens if SNC no longer has any use for the flight. They pay a penalty for breaking the contract or are they allowed to sell the flight to someone else.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Jim on 01/24/2014 05:21 pm

I assume it's booked thru LM Commercial Launch Services, right ?


It depends.  LM contracted with ULA for EFT-1
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Elmar Moelzer on 01/24/2014 05:26 pm
I cannot comment on if you missed anything or not but I didn't make it up either.  It's still an experimental vehicle under test.  Not sure why you wouldn't want to have an ejection system while performing said testing for the pilot(s).
I don't think the top of the dream chaser crew compartment comes off, or opens up. So where would the ejection seats leave the vehicle?
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Go4TLI on 01/24/2014 05:26 pm
Why would SNC pay for a launch vehicle soley for ULA's "best interest"?  That makes zero business sense and ULA is not going to donate a launch vehicle either if that is what you were trying to imply.
I think he meant that it would be in ULAs best interest to help SNC out with a good deal on the launch, since a selection of SNC (and/or the CST 100) would mean lots of extra business for ULA.

It's a contract.  And those are always negotiated.  But that doesn't mean ULA gave it away or SNC did it to prop up ULA. 

And ULA can't give a better deal to others vs the US gov't

What happens if SNC no longer has any use for the flight. They pay a penalty for breaking the contract or are they allowed to sell the flight to someone else.

They are committed to at least this flight, therefore logic would dictate they will always have a use for it.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: mheney on 01/24/2014 05:29 pm
I know I saw something about ejection seats for the piloted tests - but didn't find it in a search of the forums.   Odd - I can't imagine having read about them anywhere but here ...
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Go4TLI on 01/24/2014 05:29 pm
I cannot comment on if you missed anything or not but I didn't make it up either.  It's still an experimental vehicle under test.  Not sure why you wouldn't want to have an ejection system while performing said testing for the pilot(s).
I don't think the top of the dream chaser crew compartment comes off, or opens up. So where would the ejection seats leave the vehicle?

I would assume they will cut holes in the airframe, or it has already been scared.. 

Or maybe, tragically, SNC has not considered this and the pilots either splat on the ceiling or punch through during the event if the ejection process is required. 
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Elmar Moelzer on 01/24/2014 05:41 pm
I cannot comment on if you missed anything or not but I didn't make it up either.  It's still an experimental vehicle under test.  Not sure why you wouldn't want to have an ejection system while performing said testing for the pilot(s).
I don't think the top of the dream chaser crew compartment comes off, or opens up. So where would the ejection seats leave the vehicle?

I would assume they will cut holes in the airframe, or it has already been scared.. 

Or maybe, tragically, SNC has not considered this and the pilots either splat on the ceiling or punch through during the event if the ejection process is required.
Well from what I can see in the few pictures that give a view of the top of the current Dream Chaser ETA, there are no hatches for ejection seats right now. So they would have to cut those in. Unless the entire canopy comes off somehow. There seems to be a seam of sorts there, but that might not serve this particular function.
http://rachelsapin.files.wordpress.com/2013/04/dream-chaser-eta-complete.jpg
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Lars_J on 01/24/2014 05:48 pm
EDIT: Added hi-res pad image.

Hey, been looking everywhere for that hi res version. Thanks  8) ! Is that an SNC render ?

Yes, my google search found it on a NASA page ( http://www.nasa.gov/exploration/commercial/crew/ccicap-spacecoast.html ) - and there it is credited as coming from SNC.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: yg1968 on 01/24/2014 05:52 pm
Why would SNC pay for a launch vehicle soley for ULA's "best interest"?  That makes zero business sense and ULA is not going to donate a launch vehicle either if that is what you were trying to imply.
I think he meant that it would be in ULAs best interest to help SNC out with a good deal on the launch, since a selection of SNC (and/or the CST 100) would mean lots of extra business for ULA.

It's a contract.  And those are always negotiated.  But that doesn't mean ULA gave it away or SNC did it to prop up ULA. 

And ULA can't give a better deal to others vs the US gov't

What happens if SNC no longer has any use for the flight. They pay a penalty for breaking the contract or are they allowed to sell the flight to someone else.

They are committed to at least this flight, therefore logic would dictate they will always have a use for it.

You mean they could launch a satellite with it if DC doesn't continue?
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Eric Hedman on 01/24/2014 05:57 pm
Why would SNC pay for a launch vehicle soley for ULA's "best interest"?  That makes zero business sense and ULA is not going to donate a launch vehicle either if that is what you were trying to imply.
I think he meant that it would be in ULAs best interest to help SNC out with a good deal on the launch, since a selection of SNC (and/or the CST 100) would mean lots of extra business for ULA.

It's a contract.  And those are always negotiated.  But that doesn't mean ULA gave it away or SNC did it to prop up ULA. 

And ULA can't give a better deal to others vs the US gov't
Does anyone know if ULA or LM is investing in SNC?  It might make sense if they feel that they need to offer a complete solution launcher and spacecraft to compete with SpaceX.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: yg1968 on 01/24/2014 05:59 pm
Why would SNC pay for a launch vehicle soley for ULA's "best interest"?  That makes zero business sense and ULA is not going to donate a launch vehicle either if that is what you were trying to imply.
I think he meant that it would be in ULAs best interest to help SNC out with a good deal on the launch, since a selection of SNC (and/or the CST 100) would mean lots of extra business for ULA.

It's a contract.  And those are always negotiated.  But that doesn't mean ULA gave it away or SNC did it to prop up ULA. 

And ULA can't give a better deal to others vs the US gov't
Does anyone know if ULA or LM is investing in SNC?  It might make sense if they feel that they need to offer a complete solution launcher and spacecraft to compete with SpaceX.

When SNC was asked that question last year (when the agreement with LM was announced), Sirangelo refused to answer the question, saying it was proprietary information.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Go4TLI on 01/24/2014 06:05 pm

Does anyone know if ULA or LM is investing in SNC?  It might make sense if they feel that they need to offer a complete solution launcher and spacecraft to compete with SpaceX.

It would seem SNC is doing just fine on its own.  The whole goal of this effort is to provide an integrated capability.  Spacecraft and booster, certified to transport crews. 

I don't see why SpaceX keeps coming up for no valid reason.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: newpylong on 01/24/2014 06:07 pm
That is where the current GSDO designs are for.

GSDO is not involved with this

Wrong term. What is the ULA equivalent of GSDO that would be involved in the pad mods? Insert that name here.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: newpylong on 01/24/2014 06:12 pm

Does anyone know if ULA or LM is investing in SNC?  It might make sense if they feel that they need to offer a complete solution launcher and spacecraft to compete with SpaceX.

It would seem SNC is doing just fine on its own.  The whole goal of this effort is to provide an integrated capability.  Spacecraft and booster, certified to transport crews. 

I don't see why SpaceX keeps coming up for no valid reason.

Probably for the same reason that people complained that NASA booked an Atlas for InSight even thought Falcon would be cheaper.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: rpapo on 01/24/2014 06:13 pm
It's an evolution of the ETA with incremental upgrades to bring it closer to the planned operational flight vehicle.

0.5:  Upgraded systems for uncrewed approach and landing tests
1.0:  Further upgrades and ejection seat for crewed flights. 

Ejection seats?!? Did I miss something, or where did that come from? I don't think I've ever seen anything to indicate that DC would ever fly with ejection seats.

I cannot comment on if you missed anything or not but I didn't make it up either.  It's still an experimental vehicle under test.  Not sure why you wouldn't want to have an ejection system while performing said testing for the pilot(s).
It could be like what they did on the first couple of Shuttle flights, where only two guys went up and they supposedly had ejection seats for those flights.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Elmar Moelzer on 01/24/2014 06:17 pm
It could be like what they did on the first couple of Shuttle flights, where only two guys went up and they supposedly had ejection seats for those flights.
yeah, but it seems like they would still have to add a lot of modifications (holes, hatches, etc) to the DC canopy for the ejection seats to work. Not sure why they did not add them from the beginning.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Jim on 01/24/2014 06:17 pm

Does anyone know if ULA or LM is investing in SNC? 

ULA doesn't have the operating funds to do this and probably can't and if it could, it wouldn't since it would take Boeing and LM to agree.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: rayleighscatter on 01/24/2014 06:29 pm
Has there been any indication what the stylish, fashion forward astronaut will be wearing on this (or other DC) flight? ACES?
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Lurker Steve on 01/24/2014 06:29 pm
From the announcement, does it sounds like the same team of Lockheed engineers will be working on both Orion and Dream Chaser ? I guess that's one way to reduce overhead. Orion won't be flying often enough to keep those guys busy, and hopefully DC is designed to be relatively low maintenance. Good news for both programs.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Rocket Science on 01/24/2014 06:31 pm
Steve mentioned an ejection seat during the presser yesterday.  It's not that big a deal fitting one in nor an explosive hatch over the seat...
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: sdsds on 01/24/2014 07:03 pm
ULA can't give a better deal to others vs the US gov't

I understand how this is being reported, but can ULA even sell an Atlas directly to SNC? Or do commercial flights on Atlas need to be sold by LM? See for example: Lockheed Martin is the exclusive provider of commercial Atlas rockets. from http://www.lockheedmartin.com/us/news/press-releases/2013/september/0909-ss-atlas.html

I mention this because in a full price sale, LM would almost certainly take a cut in exchange for the sales service they provide. In this deal, ISTM there might be a possibility that LM is taking less than their full commission....
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Jim on 01/24/2014 07:27 pm

I understand how this is being reported, but can ULA even sell an Atlas directly to SNC? Or do commercial flights on Atlas need to be sold by LM? See for example: Lockheed Martin is the exclusive provider of commercial Atlas rockets. from http://www.lockheedmartin.com/us/news/press-releases/2013/september/0909-ss-atlas.html

I mention this because in a full price sale, LM would almost certainly take a cut in exchange for the sales service they provide. In this deal, ISTM there might be a possibility that LM is taking less than their full commission....

LM bought a Delta for EFT-1 from ULA. 
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: TomH on 01/25/2014 12:40 am
I don't see why SpaceX keeps coming up for no valid reason.

Respectfully, I believe DC atop F9v1.1 would be far less expensive than atop AV, and that to me is about as valid as a reason gets. If they perfect Stage 1 RTLS and still have margin to loft DC, that lowers the cost all that much more. I am not interested in an argument, but I am very open to you laying out a reasoned case for there being no valid reason to consider DC on Falcon.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: joek on 01/25/2014 01:23 am
I understand how this is being reported, but can ULA even sell an Atlas directly to SNC? Or do commercial flights on Atlas need to be sold by LM? See for example: Lockheed Martin is the exclusive provider of commercial Atlas rockets. from http://www.lockheedmartin.com/us/news/press-releases/2013/september/0909-ss-atlas.html

I mention this because in a full price sale, LM would almost certainly take a cut in exchange for the sales service they provide. In this deal, ISTM there might be a possibility that LM is taking less than their full commission....

CCtCap does not require FAA licensing for test flights (up to and including the final certification flight); this flight would fall in that category.  As a government or government-sponsored flight, that would allow a direct transaction between SNC and ULA (no need to go through LM commercial launch services).

LM bought a Delta for EFT-1 from ULA.

Not sure where that fits.  An FAA license has been issued to ULA for EFT-1.  That appears to be a first, as all previous FAA licenses have been issued to Boeing or LM commercial launch services.  If it is considered a commercial launch on Delta IV, then Boeing Commercial Launch Services would be the licensee; if it is considered a government or government-sponsored launch, then an FAA launch license would not be required.  Color me confused.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Todd Martin on 01/25/2014 01:25 am
Well, there's a conflict of interest in SpaceX providing launch services to DC since they are in competition for Commercial Crew.  Perhaps things will change in the future.

I wonder what launch vehicle DC will use for an in-flight abort test.  An Atlas V?  Orion will use a 1st stage Peacekeeper solid rocket motor.  Could SNC buy one of those?

Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: QuantumG on 01/25/2014 01:28 am
Well, there's a conflict of interest in SpaceX providing launch services to DC since they are in competition for Commercial Crew.  Perhaps things will change in the future.

In that case, Boeing has a conflict of interest providing Atlas V (via ULA) and the Centaur upper stage (directly) too. They've competing for commercial crew also, remember?

An industry is what you get when companies buy from each other.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: rayleighscatter on 01/25/2014 02:56 am

I wonder what launch vehicle DC will use for an in-flight abort test.  An Atlas V?  Orion will use a 1st stage Peacekeeper solid rocket motor.  Could SNC buy one of those?
I believe they aren't for sale and can only be used for government missions per one of the strategic arms treaties.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Lars_J on 01/25/2014 04:54 am
I wonder what launch vehicle DC will use for an in-flight abort test.  An Atlas V?  Orion will use a 1st stage Peacekeeper solid rocket motor.  Could SNC buy one of those?

A good question - are they even doing an in-flight abort test? It seems odd to announce the first orbital test flight without details about the LAS test.

But they certainly are showing that they want to compete with some initiative of their own, and that's great for everyone.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: a_langwich on 01/25/2014 06:26 am
From the announcement, does it sounds like the same team of Lockheed engineers will be working on both Orion and Dream Chaser ? I guess that's one way to reduce overhead. Orion won't be flying often enough to keep those guys busy, and hopefully DC is designed to be relatively low maintenance. Good news for both programs.


I agree, and potentially a very savvy business move.  SNC is stroking NASA's tender spots by using KSC facilities, helping keep the Orion workers busy, and using the SLF to land.  (Not to mention, based on their diagram of all the contributors to their program, they've had work done at virtually every NASA center.)  For the public, they make sure every briefing mentions the shuttle as often as possible.  They've got the big brown puppy eyes wide open, and are sending out waves of cuteness.

I was surprised by them scheduling a first launch, but I like it.  Very aggressive and ambitious, as they need to be.  They have a massive amount of work to do before then.  I hope their engineering and manufacturing execution matches their PR/networking/alliance savvy.  If it does, they will have a come-from-behind story to match companyX-who-must-not-be-named.  I hope they succeed in operating it and making a profit on flying it, regardless of how the initial commercial crew selection turns out.

Is there any chance ULA would submit requests through NASA for capabilities/compatibility at Pad 39A?
CompanyX-who-must-not-be-named might use it specifically for manned launches, and perhaps ULA would also benefit from a separate manned pad for scheduling freedom?  At least in the near term, commercial crew is the only manned gig available, so there would be no scheduling conflict for those flights.  And, both companies have equal incentive to finish it Real Soon Now for such launches.  No? 

Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: banjo on 01/25/2014 09:29 am
Does DC firing its hybrid motors inside the mating adaptor atop atlas V during pad abort have any negative impact on the required performance ?
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: newpylong on 01/25/2014 10:47 am
I don't see why SpaceX keeps coming up for no valid reason.

Respectfully, I believe DC atop F9v1.1 would be far less expensive than atop AV, and that to me is about as valid as a reason gets. If they perfect Stage 1 RTLS and still have margin to loft DC, that lowers the cost all that much more. I am not interested in an argument, but I am very open to you laying out a reasoned case for there being no valid reason to consider DC on Falcon.

There is a good reason to use Falcon (cost) - but you need to realize this choice did not occur over night. SNC had to choose a provider years ago and begin design and integration work with that provider. At that time, really the only player in the game was ULA. Falcon 9 1.1 was CAD, if that.

Fast forward to now, no one should be scratching their head why an Atlas was purchased since that is what the integration work is being done on.

Also remember SNC has mentioned (as has Boeing) that they have not ruled out F9 for future flights.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Jim on 01/25/2014 02:06 pm

Respectfully, I believe DC atop F9v1.1 would be far less expensive than atop AV, and that to me is about as valid as a reason gets. If they perfect Stage 1 RTLS and still have margin to loft DC, that lowers the cost all that much more. I am not interested in an argument, but I am very open to you laying out a reasoned case for there being no valid reason to consider DC on Falcon.

There can be many reasons.  Cost is not everything .  There is vertical integration.  And it is a competitor. Everybody assumes cost is a factor but we don't know the costs
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Lurker Steve on 01/25/2014 04:23 pm

Respectfully, I believe DC atop F9v1.1 would be far less expensive than atop AV, and that to me is about as valid as a reason gets. If they perfect Stage 1 RTLS and still have margin to loft DC, that lowers the cost all that much more. I am not interested in an argument, but I am very open to you laying out a reasoned case for there being no valid reason to consider DC on Falcon.

There can be many reasons.  Cost is not everything .  There is vertical integration.  And it is a competitor. Everybody assumes cost is a factor but we don't know the costs

For instance, our largest customer was bought by our competition a few years ago.
The rest of our customers hated that deal, because you aren't supposed to have to compete against one of your suppliers. In addition, that customer's corporate parents have decided that they aren't allowed to purchase machines from our any longer, since they hate writing checks to us.

That is one of the reasons I don't think CST-100 will ever fly on a SpaceX rocket. A certain senior executive has bashed that corporation too many times for Boeing to write SpaceX a check.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: TomH on 01/25/2014 07:05 pm
I don't see why SpaceX keeps coming up for no valid reason.

Respectfully, I believe DC atop F9v1.1 would be far less expensive than atop AV, and that to me is about as valid as a reason gets. If they perfect Stage 1 RTLS and still have margin to loft DC, that lowers the cost all that much more. I am not interested in an argument, but I am very open to you laying out a reasoned case for there being no valid reason to consider DC on Falcon.

There is a good reason to use Falcon (cost) - but you need to realize this choice did not occur over night. SNC had to choose a provider years ago and begin design and integration work with that provider. At that time, really the only player in the game was ULA. Falcon 9 1.1 was CAD, if that.

Fast forward to now, no one should be scratching their head why an Atlas was purchased since that is what the integration work is being done on.

Also remember SNC has mentioned (as has Boeing) that they have not ruled out F9 for future flights.


Respectfully, I believe DC atop F9v1.1 would be far less expensive than atop AV, and that to me is about as valid as a reason gets. If they perfect Stage 1 RTLS and still have margin to loft DC, that lowers the cost all that much more. I am not interested in an argument, but I am very open to you laying out a reasoned case for there being no valid reason to consider DC on Falcon.

There can be many reasons.  Cost is not everything .  There is vertical integration.  And it is a competitor. Everybody assumes cost is a factor but we don't know the costs

For instance, our largest customer was bought by our competition a few years ago.
The rest of our customers hated that deal, because you aren't supposed to have to compete against one of your suppliers. In addition, that customer's corporate parents have decided that they aren't allowed to purchase machines from our any longer, since they hate writing checks to us.

That is one of the reasons I don't think CST-100 will ever fly on a SpaceX rocket. A certain senior executive has bashed that corporation too many times for Boeing to write SpaceX a check.

newpylong's statement, Also remember SNC has mentioned (as has Boeing) that they have not ruled out F9 for future flights, is what I was inquiring about in my post a couple of pages back. Go4TLI then made the comment that SpaceX came up for no valid reason. I completely understand about vertical integration and that the decision for AV was made too long ago (I think the use of years is stretching it a bit when that means >1 but <2) to change LVs for the opening flight. Nevertheless, changing in the future is a reasonable option to consider.

As for not cooperating with competitors, I have to disagree. LM is working with SNC on DC, but the vehicle is flying on a Boeing supplied first stage (via ULA) and Centaur US. LM is certainly a competitor with Boeing/(McDonald/Douglas).

As for not knowing the costs, we may not know the exact costs, but IMO it isn't very credible to imply that Falcon might not be able to beat ULA's cost on AV.

I accept that there are pros and cons for SNC making an LV change for DC in the future, but I do not agree that there is NO valid reason whatsoever for the issue to even be broached.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: A_M_Swallow on 01/25/2014 07:21 pm
Complete getting the spacecraft to work with one launch vehicle before integrating it with a second.

At this stage in development the system engineers at SNC may have had talks with SpaceX but vehicle design engineers should not have been involved.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Jim on 01/25/2014 07:36 pm

As for not cooperating with competitors, I have to disagree. LM is working with SNC on DC, but the vehicle is flying on a Boeing supplied first stage (via ULA) and Centaur US. LM is certainly a competitor with Boeing/(McDonald/Douglas).


You are wrong on many levels.

A. Atlas first stage is not Boeing supplied.  It is ULA and nothing but ULA.
B.  Altas first stage was a LM design and formerly LM produced.  Notice the word "was". It is now a ULA design and ULA produced.
c.  There are no longer any remnants of McDonald/Douglas.
d.  The only way LM and Boeing are competing is DC vs CST-100 spacecraft, not by anything related to launch vehicles.  They win either way if a ULA booster is used.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Jim on 01/25/2014 07:37 pm
(I think the use of years is stretching it a bit when that means >1 but <2) to change LVs for the opening flight.

longer than 2 years.  It takes two years for a comsat
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Jim on 01/25/2014 07:39 pm

As for not knowing the costs, we may not know the exact costs, but IMO it isn't very credible to imply that Falcon might not be able to beat ULA's cost on AV.


It isn't very credible to think that either
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: baldusi on 01/25/2014 07:47 pm

As for not knowing the costs, we may not know the exact costs, but IMO it isn't very credible to imply that Falcon might not be able to beat ULA's cost on AV.


It isn't very credible to think that either
To expand on what Jim said, even if Falcon was, indeed, cheaper, the integratipn cost might more than make up for the difference. Remember that Dream chaser needs a lot o aero validation and studies, plus the whole access and crew egress issues. That alone should make switching LV pretty expensive.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Lurker Steve on 01/25/2014 09:54 pm

As for not knowing the costs, we may not know the exact costs, but IMO it isn't very credible to imply that Falcon might not be able to beat ULA's cost on AV.


It isn't very credible to think that either
To expand on what Jim said, even if Falcon was, indeed, cheaper, the integratipn cost might more than make up for the difference. Remember that Dream chaser needs a lot o aero validation and studies, plus the whole access and crew egress issues. That alone should make switching LV pretty expensive.

DC has spent a lot of time with Wind Tunnel testing at a couple of NASA centers. That would all have to be repeated, as well as a re-design of the interface between DC and the upper stage. Besides having more ISP, does the Centaur have a wider diameter than the F9 US ?

Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: ugordan on 01/25/2014 10:08 pm
Besides having more ISP, does the Centaur have a wider diameter than the F9 US ?

Centaur is 10 feet, Falcon 9 is 12 feet in diameter.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: docmordrid on 01/26/2014 02:10 am
Says here smaller; Centaur being 3.05m vs. F9-S2's 3.66m.

http://www.spaceflight101.com/atlas-v-551.html
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: newpylong on 01/27/2014 12:03 am


newpylong's statement, Also remember SNC has mentioned (as has Boeing) that they have not ruled out F9 for future flights, is what I was inquiring about in my post a couple of pages back. Go4TLI then made the comment that SpaceX came up for no valid reason. I completely understand about vertical integration and that the decision for AV was made too long ago (I think the use of years is stretching it a bit when that means >1 but <2) to change LVs for the opening flight. Nevertheless, changing in the future is a reasonable option to consider.



6 years, not 1 or 2. As I said, this did not happen overnight and a lot of work goes into qualifying a spacecraft (manned) with a lift vehicle. SNC entered into agreement with ULA in mid 2007 to begin work on DC/Atlas! So long ago it was SpaceDev, not SNC actually.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: LouScheffer on 01/27/2014 03:18 am

And ULA can't give a better deal to others vs the US gov't
Without knowing the details of the contract, it might well be possible to "lawyer" around this restriction.  For example, this flight does not need a fairing, so ULA could create a "no fairing" option and price it at what they want.  Then they can offer to sell this configuration to the government at the same price, thus meeting the letter of *that* contract, while knowing the government is exceedingly unlikely to take them up on this offer.

I know nothing whatsoever about this particular contract, and whether this is the case, only that "most preferred customer" clauses are often easy to get around.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: BrightLight on 01/28/2014 03:25 pm
There are some logistical issues with the DC integrated stack that are coming to light - the LV does not require the additional complexity, time and effort of SRB integration onto the LV and DC does not require the special handling of toxic/dangerous fuel on vehicle integration with he LV as well as simplified landing procedures.
How much does the simplified operations give the DC in terms of cost reduction and safety compared to its competition?
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Jim on 01/28/2014 03:33 pm
There are some logistical issues with the DC integrated stack that are coming to light - the LV does not require the additional complexity, time and effort of SRB integration onto the LV and DC does not require the special handling of toxic/dangerous fuel on vehicle integration with he LV as well as simplified landing procedures.
How much does the simplified operations give the DC in terms of cost reduction and safety compared to its competition?

Other than an extra day for SRM installation and the cost of the SRM, not really simplified operations for the LV.   The Centaur uses hydrazine and so it is already present before the spacecraft is mated.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Jim on 01/28/2014 03:35 pm
, so ULA could create a "no fairing" option

And that itself costs more than a mission with a fairing because of the extra analyses.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Robotbeat on 01/28/2014 03:37 pm
There are some logistical issues with the DC integrated stack that are coming to light - the LV does not require the additional complexity, time and effort of SRB integration onto the LV and DC does not require the special handling of toxic/dangerous fuel on vehicle integration with he LV as well as simplified landing procedures.
How much does the simplified operations give the DC in terms of cost reduction and safety compared to its competition?
That really depends. I've seen illustrations showing at least 2 srbs on an atlas v for launching Dreamchaser.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: BrightLight on 01/28/2014 03:59 pm
There are some logistical issues with the DC integrated stack that are coming to light - the LV does not require the additional complexity, time and effort of SRB integration onto the LV and DC does not require the special handling of toxic/dangerous fuel on vehicle integration with he LV as well as simplified landing procedures.
How much does the simplified operations give the DC in terms of cost reduction and safety compared to its competition?
That really depends. I've seen illustrations showing at least 2 srbs on an atlas v for launching Dreamchaser.
As of Aug of 2011, from a vidcast on you tube, http://www.youtube.com/watch?v=D7sWtEAddkM apparently Sirangelo said the 402 configuration will be used, I did not watch the whole video.  This doesn't mean it can't change, but that's the best info I have.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Prober on 01/28/2014 04:06 pm
There are some logistical issues with the DC integrated stack that are coming to light - the LV does not require the additional complexity, time and effort of SRB integration onto the LV and DC does not require the special handling of toxic/dangerous fuel on vehicle integration with he LV as well as simplified landing procedures.
How much does the simplified operations give the DC in terms of cost reduction and safety compared to its competition?

Other than an extra day for SRM installation and the cost of the SRM, not really simplified operations for the LV.   The Centaur uses hydrazine and so it is already present before the spacecraft is mated.

Doesn't the dual RL-10 use a much larger (taller) Centaur?   Any additional RCS margin added?
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Jim on 01/28/2014 04:08 pm

Doesn't the dual RL-10 use a much larger (taller) Centaur?   Any additional RCS margin added?


Neither
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: adrianwyard on 01/28/2014 04:11 pm
There are some logistical issues with the DC integrated stack that are coming to light - the LV does not require the additional complexity, time and effort of SRB integration onto the LV and DC does not require the special handling of toxic/dangerous fuel on vehicle integration with he LV as well as simplified landing procedures.
How much does the simplified operations give the DC in terms of cost reduction and safety compared to its competition?
That really depends. I've seen illustrations showing at least 2 srbs on an atlas v for launching Dreamchaser.
We've been hearing AV402 consistently for years. I think depictions with SRBs date back to SpaceDev days.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: BrightLight on 01/28/2014 04:14 pm
There are some logistical issues with the DC integrated stack that are coming to light - the LV does not require the additional complexity, time and effort of SRB integration onto the LV and DC does not require the special handling of toxic/dangerous fuel on vehicle integration with he LV as well as simplified landing procedures.
How much does the simplified operations give the DC in terms of cost reduction and safety compared to its competition?
That really depends. I've seen illustrations showing at least 2 srbs on an atlas v for launching Dreamchaser.
We've been hearing AV402 consistently for years. I think depictions with SRBs date back to SpaceDev days.
Just to "ice the cake" the NASA site http://www.nasa.gov/offices/c3po/partners/ccdev_info_prt.htm states the use of the Atlas V 402 configuration.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Star One on 01/28/2014 05:44 pm
To reach orbits that are above the ISS would the Atlas have to use SRBs to launch DC, or can DC reach higher orbits whilst still being launched on the 402?
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Lee Jay on 02/16/2014 02:48 pm
I was at the Wings over the Rockies Air and Space museum yesterday for an R/C airplane event, and look what I got to see there!  I didn't know the thing had 10 seats in it in this configuration.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Ronsmytheiii on 02/16/2014 07:36 pm
I was at the Wings over the Rockies Air and Space museum yesterday for an R/C airplane event, and look what I got to see there!  I didn't know the thing had 10 seats in it in this configuration.

Why is it at that museum, is SNC done with it? SNC "borrowed" the HL-20 mockup from the Virginia Air and Space Museum, if they are done with it shouldn't they return it?
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Rocket Science on 02/16/2014 07:52 pm
I was at the Wings over the Rockies Air and Space museum yesterday for an R/C airplane event, and look what I got to see there!  I didn't know the thing had 10 seats in it in this configuration.
Thanks Lee Jay, looking good there! :)
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Lee Jay on 02/16/2014 09:18 pm
I was at the Wings over the Rockies Air and Space museum yesterday for an R/C airplane event, and look what I got to see there!  I didn't know the thing had 10 seats in it in this configuration.

Why is it at that museum, is SNC done with it? SNC "borrowed" the HL-20 mockup from the Virginia Air and Space Museum, if they are done with it shouldn't they return it?

I have absolutely no idea what the arrangements are.

According to this facebook post, it was at CU Boulder before the move in November of 2013.

https://www.facebook.com/media/set/?set=a.10151790156295678.1073741833.158649375677&type=3
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: R7 on 02/23/2014 11:39 am
potentially dumb (but don't know anything about air/spacecraft tyres so here goes) L2 inspired question: are the tyres tubeless?
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: oiorionsbelt on 03/02/2014 09:59 pm
No idea what DC will use but the Shuttle's tires were pressurized.

"Like most aircraft tires, the Space Shuttle tires are filled with nitrogen because of its stability at different altitudes and temperatures. Due to the extremely heavy loads, these bias ply tires are inflated to 340 psi (main gear) and 300 psi (nose gear).The main landing gear shuttle tires are only used one time, and the nose landing gear tires are used for two landings."


http://www.airmichelin.com/generalcontent.aspx?id=149
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Lars_J on 03/11/2014 09:09 pm
Per this update thread post, http://forum.nasaspaceflight.com/index.php?topic=29416.msg1170614#msg1170614, SNC is starting cooperation with MSFC.

The cynic in me might see this as a way to get the inside track with the down-select. Involve as many NASA centers as possible. (JSC, KSC, and now MSFC)
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: BrightLight on 03/11/2014 10:05 pm
Per this update thread post, http://forum.nasaspaceflight.com/index.php?topic=29416.msg1170614#msg1170614, SNC is starting cooperation with MSFC.

The cynic in me might see this as a way to get the inside track with the down-select. Involve as many NASA centers as possible. (JSC, KSC, and now MSFC)
I don't know if that would help but if your going to play the game - its not a bad strategy.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: spacecane on 03/12/2014 09:46 am
Per this update thread post, http://forum.nasaspaceflight.com/index.php?topic=29416.msg1170614#msg1170614, SNC is starting cooperation with MSFC.

The cynic in me might see this as a way to get the inside track with the down-select. Involve as many NASA centers as possible. (JSC, KSC, and now MSFC)
I don't know if that would help but if your going to play the game - its not a bad strategy.

That's how the world works with Government contracts.  These companies have to play the game.  Another thing that helps them is that DC is a VTHL vehicle.  People like spaceplanes because they look like science fiction space vehicles.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Prober on 03/12/2014 03:14 pm
Maybe someone could clear up a point for me. :P

Couldn't the Dream Chaser use the Gulfstream II Shuttle Training Aircraft for testing?

If the Dream Chaser wins wouldn't this be a cheap trainer, just re-programed?

Reason I bring this up; looks like its heading to Huntsville, Alabama for space camp etc.

More info: http://igg.me/at/STANASA945

Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: adrianwyard on 03/12/2014 03:52 pm
Reprogramming the STA would take you part way to a DC trainer (once DC flight testing has revealed all its characteristics). But to make it realistic you'd also need to redo the left seat instruments/layout and flight-controls and of course the displays to make it look and behave like DC cockpit rather than a shuttle. Until you do that, ground-based simulators might actually do a better job at prepairing pilots.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Rocket Science on 03/12/2014 04:03 pm
Reprogramming the STA would take you part way to a DC trainer (once DC flight testing has revealed all its characteristics). But to make it realistic you'd also need to redo the left seat instruments/layout and flight-controls and of course the displays to make it look and behave like DC cockpit rather than a shuttle. Until you do that, ground-based simulators might actually do a better job at prepairing pilots.
Except they don’t give you that “pucker factor”... ;D
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Jim on 03/12/2014 04:44 pm

Couldn't the Dream Chaser use the Gulfstream II Shuttle Training Aircraft for testing?


They all have been put out to pasture and are no longer available
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Todd Martin on 03/12/2014 04:48 pm
I believe Sierra Nevada's agreement via Space Act Agreement with Marshall Space Flight Center indicates SNC has one or more serious potential customers wanting to fly a scientific payload on Dreamchaser.  After all, SNC has committed to purchasing an Atlas V launch for an un-manned test orbital test flight.  It is natural that SNC would want to earn some additional revenue with the flight.

If there was no customer interest, SNC would not be investing time and money into developing the mechanisms to accept such payloads.  I realize SpaceX has not had any luck so far with DragonLab, but this may be more of a case of limited resources & higher priority paying customers.  I think it would be much better for DC to fly an inexpensive scientific payload on its maiden flight than a block of cheese...
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Prober on 03/12/2014 05:15 pm
Reprogramming the STA would take you part way to a DC trainer (once DC flight testing has revealed all its characteristics). But to make it realistic you'd also need to redo the left seat instruments/layout and flight-controls and of course the displays to make it look and behave like DC cockpit rather than a shuttle. Until you do that, ground-based simulators might actually do a better job at prepairing pilots.

See the problem as I see it, is that "few" are looking ahead.    The jet hasn't been transferred yet, so it "could" be available if someone thought ahead, and fought for it.

That crowd funding needs to find 70,000$ just to setup for the plane.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: JasonAW3 on 03/12/2014 05:28 pm

As for not knowing the costs, we may not know the exact costs, but IMO it isn't very credible to imply that Falcon might not be able to beat ULA's cost on AV.


It isn't very credible to think that either
To expand on what Jim said, even if Falcon was, indeed, cheaper, the integratipn cost might more than make up for the difference. Remember that Dream chaser needs a lot o aero validation and studies, plus the whole access and crew egress issues. That alone should make switching LV pretty expensive.

True, at least in the short term. However, if SpaceX can bring back the F9 Stack for Reuse, then that expense would get ammortized over several flights.

Another point is that the different craft have different reentry characterics.  The DC is a lower G LEO return vehicle with lots of cross range, whereas the Dragon appears to be able to handle a much faster and higher G return, possibly from BEO, but has limited cross range.

Both craft have their pluses and minuses, but overall, seem to be slightly more specialized to the tasks that they were designed for.  You may be able to take a Dragon through a Lunar Return but the Dreamchaser is strictly a Low orbit bird.  In the case of someone who is injured or deconditioned to Earth's gravity, I'd want to use the Dream Chaser if possible.  Coming back from Mars or the Moon, the Dragon Rider.  Having the two different types of craft available, plus being able to use either the Atlas or F9 stacks, plus the differing cargo / passenger payloads that they can carry, improves the flexibility of both systems.

It simply comes down to a question of expense and capibility. While a reusable stack would cost far less in the long term, in the short term, until that reusability is confirmed, using the more expensive Atlas stack is a more logical choice for its' proven ability.

Jason
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: JasonAW3 on 03/12/2014 05:35 pm
Reprogramming the STA would take you part way to a DC trainer (once DC flight testing has revealed all its characteristics). But to make it realistic you'd also need to redo the left seat instruments/layout and flight-controls and of course the displays to make it look and behave like DC cockpit rather than a shuttle. Until you do that, ground-based simulators might actually do a better job at prepairing pilots.

See the problem as I see it, is that "few" are looking ahead.    The jet hasn't been transferred yet, so it "could" be available if someone thought ahead, and fought for it.

That crowd funding needs to find 70,000$ just to setup for the plane.

If the cockpit equipment railing system is anything like modern, then swapping out the instrumentation shouldn't be too difficult, but artificially replicating the flight characteristics of the DC may require a few physical mods to the aircraft.  (Although most of the time nowdays, a computer interface between the flight controls and the flight surfaces should be able to replicate most of the flight characteristics of the DC.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Rocket Science on 03/12/2014 06:03 pm
Reprogramming the STA would take you part way to a DC trainer (once DC flight testing has revealed all its characteristics). But to make it realistic you'd also need to redo the left seat instruments/layout and flight-controls and of course the displays to make it look and behave like DC cockpit rather than a shuttle. Until you do that, ground-based simulators might actually do a better job at prepairing pilots.

See the problem as I see it, is that "few" are looking ahead.    The jet hasn't been transferred yet, so it "could" be available if someone thought ahead, and fought for it.

That crowd funding needs to find 70,000$ just to setup for the plane.

If the cockpit equipment railing system is anything like modern, then swapping out the instrumentation shouldn't be too difficult, but artificially replicating the flight characteristics of the DC may require a few physical mods to the aircraft.  (Although most of the time nowdays, a computer interface between the flight controls and the flight surfaces should be able to replicate most of the flight characteristics of the DC.
The early STA used extra ventral fins to increase drag as on the Orbiter the later GII used a combination of computer controls, powers settings and gear to simulate approach. You can use the T-38 with its large speed brake and gear down as well to sim approach as well...

http://www.jsc.nasa.gov/history/oral_histories/WhittleDW/gallery/index_5.htm
http://www.nasa.gov/mission_pages/shuttle/flyout/t38flyout.html

Edit to add: The T-38 was used during the HL-20program to sim pad abort tests with a covered windscreen as would be viewed by the pilot astronaut...

My Lifting Body Q&A thread:
http://forum.nasaspaceflight.com/index.php?topic=29126.msg992526#msg992526
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Ben the Space Brit on 03/17/2014 01:17 pm
I like this graphic from the presser, interesting view into the multiple roles that SNC envisions for DC.

http://www.youtube.com/watch?v=ankPUlGngGY (http://www.youtube.com/watch?v=ankPUlGngGY)

Looks like SNC have decided to promote DC as an all-missions solution for NASA in LEO.

The Russians once developed an aerocapture-then-re-entry profile so that a lifting body could fly to the Moon and back. Would DC be able to fly that profile?
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: douglas100 on 03/17/2014 03:47 pm

The Russians once developed an aerocapture-then-re-entry profile so that a lifting body could fly to the Moon and back. Would DC be able to fly that profile?

What profile was that?
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Robotbeat on 03/17/2014 03:54 pm
There are concepts for how to return DC from the Moon via a /negative lifting/ reentry. I think they assumed an ablative (but replaceable) heatshield, though. Even so, multiple pass reentry /might/ make it doable with tiles...
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: rpapo on 03/17/2014 04:21 pm
There are concepts for how to return DC from the Moon via a /negative lifting/ reentry. I think they assumed an ablative (but replaceable) heatshield, though. Even so, multiple pass reentry /might/ make it doable with tiles...
Whatever happened to the metal tile system they were doing for the X-33?  Wouldn't that be applicable here?

http://www.nasa.gov/centers/ames/news/releases/1999/99_09AR.html
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Elmar Moelzer on 03/17/2014 05:17 pm
There are concepts for how to return DC from the Moon via a /negative lifting/ reentry. I think they assumed an ablative (but replaceable) heatshield, though. Even so, multiple pass reentry /might/ make it doable with tiles...
Whatever happened to the metal tile system they were doing for the X-33?  Wouldn't that be applicable here?

http://www.nasa.gov/centers/ames/news/releases/1999/99_09AR.html
Someone correct me if I am wrong, but I think those tiles were less capable (but easier to handle) than the shuttle heritage tiles DC is using.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: arachnitect on 03/17/2014 07:04 pm
I like this graphic from the presser, interesting view into the multiple roles that SNC envisions for DC.

http://www.youtube.com/watch?v=ankPUlGngGY (http://www.youtube.com/watch?v=ankPUlGngGY)

Looks like SNC have decided to promote DC as an all-missions solution for NASA in LEO.

[...]

http://forum.nasaspaceflight.com/index.php?topic=29416.msg1172803#msg1172803

As cool as it would be to see any of these missions, I don't think they will ever happen.

1. Why would you use DC to deploy satellites? All you've done is made the most inefficient PLF in history, and it really isn't set up for servicing missions.

2. Extended duration missions. DC is small to begin with, 3 weeks? It's gonna be cozy. And what are they proposing to do that can't be done on ISS or an unmanned platform?

3. Using DC for unmanned science missions. What capability does it offer? You've just built a really expensive S/C bus with a sharply limited operational life. If NASA really wanted to do something like this, X-37 would be a better platform.

SNC is abusing shuttle nostalgia.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Ben the Space Brit on 03/17/2014 07:19 pm

The Russians once developed an aerocapture-then-re-entry profile so that a lifting body could fly to the Moon and back. Would DC be able to fly that profile?

What profile was that?

Multiple-skip re-entry with at least one pass through the atmosphere to burn off excess energy before the actual final EDL.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: adrianwyard on 03/17/2014 07:33 pm
There are concepts for how to return DC from the Moon via a /negative lifting/ reentry. I think they assumed an ablative (but replaceable) heatshield, though. Even so, multiple pass reentry /might/ make it doable with tiles...
Whatever happened to the metal tile system they were doing for the X-33?  Wouldn't that be applicable here?

http://www.nasa.gov/centers/ames/news/releases/1999/99_09AR.html
Also mentioned in another thread:
http://forum.nasaspaceflight.com/index.php?topic=1184.msg1084547#msg1084547
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: A_M_Swallow on 03/17/2014 08:13 pm
{snip}
2. Extended duration missions. DC is small to begin with, 3 weeks? It's gonna be cozy. And what are they proposing to do that can't be done on ISS or an unmanned platform?

{snip}

They are likely to need some sort of mission module for 3 weeks, possibly launched separately.  (Or the flight is limited by consumables to 2 people.)

The DC can fly to many orbits where as the ISS is limited to its current one.

Using robotic arms from an unmanned platform would be unusual.  You need people to perform a space walk.

A satellite or spacecraft massing 30 tonne or may could be created by inspace assembly.  The liquids and electrical connections between modules may need a human to connect them.  The ISS ones did.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: redliox on 03/17/2014 09:19 pm
http://forum.nasaspaceflight.com/index.php?topic=29416.msg1172803#msg1172803

As cool as it would be to see any of these missions, I don't think they will ever happen.

1. Why would you use DC to deploy satellites? All you've done is made the most inefficient PLF in history, and it really isn't set up for servicing missions.

2. Extended duration missions. DC is small to begin with, 3 weeks? It's gonna be cozy. And what are they proposing to do that can't be done on ISS or an unmanned platform?

3. Using DC for unmanned science missions. What capability does it offer? You've just built a really expensive S/C bus with a sharply limited operational life. If NASA really wanted to do something like this, X-37 would be a better platform.

SNC is abusing shuttle nostalgia.

I dunno on all accounts, but ultimately it'll depend on how profitable it proves to NASA & SN.  If it proves useful, then they might tinker a bit to see if more could be used.

I do agree with you about deploying satellites and long-duration crewed missions - DC is way too small for either (discounting maybe micro/nano/cubsats).  Unless it's plugged into a space station or a bigger habitat module, I doubt I would want to spend more than 2 days in a cramped space plane; we all know how claustrophobic air planes already are....

However, if anything else, I could see SC being given a robot arm and doing minor servicing missions.  Considering how the U.S. air force has had its mini-shuttle experiments orbiting for a year, likewise a DC could be unmanned and put on satellite duty.

The DC is no space shuttle, but it could be a hell of a lot more efficient than it's larger predecessor.  Again it's up to SN.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: BrightLight on 03/17/2014 09:55 pm

http://forum.nasaspaceflight.com/index.php?topic=29416.msg1172803#msg1172803

As cool as it would be to see any of these missions, I don't think they will ever happen.

1. Why would you use DC to deploy satellites? All you've done is made the most inefficient PLF in history, and it really isn't set up for servicing missions.

2. Extended duration missions. DC is small to begin with, 3 weeks? It's gonna be cozy. And what are they proposing to do that can't be done on ISS or an unmanned platform?

3. Using DC for unmanned science missions. What capability does it offer? You've just built a really expensive S/C bus with a sharply limited operational life. If NASA really wanted to do something like this, X-37 would be a better platform.

SNC is abusing shuttle nostalgia.

1. Being able to control the insertion of a small satellite as part of a larger science/technology mission could be quite useful and potentially cheaper/faster then deployment from ISS.
2. DC was designed for 7 people, flying 2 with science racks and logistics will be cramped but possible, this could be useful for sensitive micro-g missions.
3. Unmanned DC is a interesting option for a operational vehicle - the X-37 is an experimental vehicle and not operational.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Lars_J on 03/17/2014 10:12 pm

http://forum.nasaspaceflight.com/index.php?topic=29416.msg1172803#msg1172803

As cool as it would be to see any of these missions, I don't think they will ever happen.

1. Why would you use DC to deploy satellites? All you've done is made the most inefficient PLF in history, and it really isn't set up for servicing missions.

2. Extended duration missions. DC is small to begin with, 3 weeks? It's gonna be cozy. And what are they proposing to do that can't be done on ISS or an unmanned platform?

3. Using DC for unmanned science missions. What capability does it offer? You've just built a really expensive S/C bus with a sharply limited operational life. If NASA really wanted to do something like this, X-37 would be a better platform.

SNC is abusing shuttle nostalgia.

1. Being able to control the insertion of a small satellite as part of a larger science/technology mission could be quite useful and potentially cheaper/faster then deployment from ISS.

And this is most faster or cheaper than as a secondary payload? (or even primary payload on an Atlas V without DC)

2. DC was designed for 7 people, flying 2 with science racks and logistics will be cramped but possible, this could be useful for sensitive micro-g missions.

If you are flying sensitive micro-G experiments in a small spacecraft, you don't want crew aboard. The slightest movements would have an effect. If unmanned, that would make more sense. (like Dragonlab)

3. Unmanned DC is a interesting option for a operational vehicle - the X-37 is an experimental vehicle and not operational.

Semantics, really. The way the X-37 has been used recently suggests that is has transitioned to becoming an operational platform for experimental payloads. Despite its name.

I agree with arachnitect that much of this certainly sounds like Shuttle level nostalgia.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: JAFO on 03/17/2014 10:54 pm
Reprogramming the STA would take you part way to a DC trainer (once DC flight testing has revealed all its characteristics). But to make it realistic you'd also need to redo the left seat instruments/layout and flight-controls and of course the displays to make it look and behave like DC cockpit rather than a shuttle. Until you do that, ground-based simulators might actually do a better job at prepairing pilots.
Except they don’t give you that “pucker factor”... ;D

You might be surprised. In a ground based sim you can take "Bad days" all the way to impact, can't do that in a real airplane. With a good IP it's surprising how much you can sweat in a 2 hour sim.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Rocket Science on 03/17/2014 11:45 pm
Reprogramming the STA would take you part way to a DC trainer (once DC flight testing has revealed all its characteristics). But to make it realistic you'd also need to redo the left seat instruments/layout and flight-controls and of course the displays to make it look and behave like DC cockpit rather than a shuttle. Until you do that, ground-based simulators might actually do a better job at prepairing pilots.
Except they don’t give you that “pucker factor”... ;D

You might be surprised. In a ground based sim you can take "Bad days" all the way to impact, can't do that in a real airplane. With a good IP it's surprising how much you can sweat in a 2 hour sim.
Oh, I got some pit stains from logging sim time and had an “almost” bad day in real one... Sometimes you can shake it off and sometimes you can’t...
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Elmar Moelzer on 03/19/2014 02:07 pm
Am I fantasizing, or was there once an concept for a sort of (non reusable) service module in the DC to Atlas- adapter? I clarly remember Hermes having that too, but I vaguely remember a similar concept for the DC. If this exists, it could increase the on orbit life time of the DC quite a bit (might need a bigger version of the Atlas to launch though).
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: BrightLight on 03/19/2014 02:51 pm
Am I fantasizing, or was there once an concept for a sort of (non reusable) service module in the DC to Atlas- adapter? I clarly remember Hermes having that too, but I vaguely remember a similar concept for the DC. If this exists, it could increase the on orbit life time of the DC quite a bit (might need a bigger version of the Atlas to launch though).
There was I believe a concept for the HL-20/NLS to use a "caboose" mission module, I don't recall a similar plan for the DC. What version of the LV would be used?, how much would it weigh?
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Ben the Space Brit on 03/19/2014 02:59 pm
Am I fantasizing, or was there once an concept for a sort of (non reusable) service module in the DC to Atlas- adapter? I clarly remember Hermes having that too, but I vaguely remember a similar concept for the DC. If this exists, it could increase the on orbit life time of the DC quite a bit (might need a bigger version of the Atlas to launch though).

There was I believe a concept for the HL-20/NLS to use a "caboose" mission module, I don't recall a similar plan for the DC. What version of the LV would be used?, how much would it weigh?

It should be theoretically possible. Atlas-V-552 might be able to manage and Atlas-V-5H2 would definitely be able to do it. Ariane-V-ECA could probably manage it too.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: adrianwyard on 03/19/2014 03:50 pm
I think you might be waiting a long time for Atlas V Heavy. Some of the options could be quite light, solar arrays for example. Or minimalist satellite grappling hardware, that would allow EVA servicing through the rear hatch.

FYI the 'towed package' and servicing was been discussed upthread and elsewhere:

http://forum.nasaspaceflight.com/index.php?topic=29416.msg1008362;topicseen#msg1008362
http://forum.nasaspaceflight.com/index.php?topic=28805.msg894538;topicseen#msg894538
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: notsorandom on 03/19/2014 05:39 pm

The Russians once developed an aerocapture-then-re-entry profile so that a lifting body could fly to the Moon and back. Would DC be able to fly that profile?

What profile was that?
Ben may be talking about the reentry profile of the Zond missions.
"Skip entry was first imagined in the 1930s by Eugen Sänger, who proposed a suborbital skipping trajectory for the German Silbervogel bomber, which never flew. The technique was used by the Zond series of circumlunar spacecraft, which planned for one skip before landing. Zond 6, Zond 7 and Zond 8 made successful skip entries, although Zond 5 did not."
http://en.wikipedia.org/wiki/Skip_reentry
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: arachnitect on 03/19/2014 09:25 pm
Am I fantasizing, or was there once an concept for a sort of (non reusable) service module in the DC to Atlas- adapter? I clarly remember Hermes having that too, but I vaguely remember a similar concept for the DC. If this exists, it could increase the on orbit life time of the DC quite a bit (might need a bigger version of the Atlas to launch though).

There was I believe a concept for the HL-20/NLS to use a "caboose" mission module, I don't recall a similar plan for the DC. What version of the LV would be used?, how much would it weigh?

It should be theoretically possible. Atlas-V-552 might be able to manage and Atlas-V-5H2 would definitely be able to do it. Ariane-V-ECA could probably manage it too.

Not that it would ever happen, but it would be better to launch DC and the mission module separately. More performance and don't have to redo all the aerodynamic and loads analysis for a new LV.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: adrianwyard on 03/19/2014 09:36 pm
If the external hardware can fit in the Centaur adapter as a 'towed package' then there's no change in outer mold line/wind tunnel data. This seems to be what's depicted in SNCs slides. It does seem rather limited however, compared to something like the Dragon's trunk.

Slides in update thread:
http://forum.nasaspaceflight.com/index.php?topic=29416.msg1172803#msg1172803
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: BrightLight on 03/19/2014 09:47 pm
If the external hardware can fit in the Centaur adapter as a 'towed package' then there's no change in outer mold line/wind tunnel data. This seems to be what's depicted in SNCs slides. It does seem rather limited however, compared to something like the Dragon's trunk.
Would it be possible to extend the base of the the DC-to-Atlas adapter by 2 meters? or are the aerodynamic loads so high that a new wind- tunnel analysis and certification would need to be performed ?
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: douglas100 on 03/19/2014 09:54 pm

The Russians once developed an aerocapture-then-re-entry profile so that a lifting body could fly to the Moon and back. Would DC be able to fly that profile?

What profile was that?
Ben may be talking about the reentry profile of the Zond missions.
"Skip entry was first imagined in the 1930s by Eugen Sänger, who proposed a suborbital skipping trajectory for the German Silbervogel bomber, which never flew. The technique was used by the Zond series of circumlunar spacecraft, which planned for one skip before landing. Zond 6, Zond 7 and Zond 8 made successful skip entries, although Zond 5 did not."
http://en.wikipedia.org/wiki/Skip_reentry

Thanks. I guessed that might have been the reference. The Zond descent module was essentially a variant of Soyuz, and though able to produce lift, was certainly not a lifting body like DC. But I don't know of a reason why a lifting body like DC couldn't make such an entry from a lunar trajectory, given a robust enough TPS. However I think there is very little evidence that SNC is considering such a thing for Dream Chaser.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Lars_J on 03/19/2014 09:59 pm
If the external hardware can fit in the Centaur adapter as a 'towed package' then there's no change in outer mold line/wind tunnel data. This seems to be what's depicted in SNCs slides. It does seem rather limited however, compared to something like the Dragon's trunk.
Would it be possible to extend the base of the the DC-to-Atlas adapter by 2 meters? or are the aerodynamic loads so high that a new wind- tunnel analysis and certification would need to be performed ?

How are you going to handle aborts?
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: adrianwyard on 03/19/2014 10:55 pm
It's not just aborts that are the problem (when presumably you sever connections and leave the package behind) using the hybrid motors at all is potentially going to plume, or at least heat whatever is back there. To clarify: these are OMS engines too, not just for abort.

In this post I propose a rather wacky solution: http://forum.nasaspaceflight.com/index.php?topic=29416.msg1008362;topicseen#msg1008362
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Elmar Moelzer on 03/20/2014 01:26 pm
How are you going to handle aborts?
Why would there be any difference for aborts? As far as I understand, the interstage - mission module thing would be detached from the DC along with the rest of the booster. Or am I missing something?
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: BrightLight on 03/20/2014 01:35 pm
How are you going to handle aborts?
Why would there be any difference for aborts? As far as I understand, the interstage - mission module thing would be detached from the DC along with the rest of the booster. Or am I missing something?
I was imagining that the mission module would fit between the two OMS/abort engines, kind of like BEAM.  In the case of abort, the explosive bolts/cords would be ignited and the abort profile goes the nominal trajectory.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: BrightLight on 03/20/2014 01:53 pm
I don't know if this is how the DC adapter really is supposed to work, but a mission module (BEAM-like) could be possible placed in place of  the "cone" connecting to the LIDS - how that would affect performance, safety, aborts, etc. - I can't even begin to imagine.
The images came from:
http://orbiter-forum.com/showthread.php?t=31010&page=5 and the artist who made them is Chuck Tetakel.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Jim on 03/20/2014 01:58 pm
I don't know if this is how the DC adapter really is supposed to work, but a mission module (BEAM-like) could be possible placed in place of  the "cone" connecting to the LIDS - how that would affect performance, safety, aborts, etc. - I can't even begin to imagine.
The images came from:
http://orbiter-forum.com/showthread.php?t=31010&page=5 and the artist who made them is Chuck Tetakel.

That would have orbital debris issues.

And spacecraft don't separate at the Centaur interface.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: adrianwyard on 03/20/2014 03:13 pm
I'm sure you could jettison those fairings on the way uphill, but the big issue I see is that mission module will be torched by the engines during orbital maneuvers.  :o
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: BrightLight on 03/20/2014 03:18 pm
I'm sure you could jettison those fairings on the way uphill, but the big issue I see is that mission module will be torched by the engines during orbital maneuvers.  :o
I think putting  heat shield plates on the mission module would be adequate but as Jim says - more debris and that debris might become a problem if it is near a larger system - either a satellite for repair or a station.  I am sure a engineering fix is possible for the exhaust gases from the engine.  Is the Centaur US able to handle the bending moment of the extended stack?
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: adrianwyard on 03/20/2014 03:43 pm
The fairings need not cause a debris issue: they would land in the ocean like other payload fairings, jettisoned during ascent, when out of the discernible atmosphere.

But more to the point, why go to all this bother (adding TPS/weight) to the mission module. (Note: if the plume impinges the module, it will reflect and cause unwanted yaw if used singly.)

i.e. what mission does this sort of module enable for DC?
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: BrightLight on 03/20/2014 03:49 pm
The fairings need not cause a debris issue: they would land in the ocean like other payload fairings, jettisoned during ascent, when out of the discernable atmosphere.

But more to the point, why go to all this bother (adding TPS/weight) to the mission module. (Note: if the plume impinges the module, it will reflect and cause unwanted yaw.)

i.e. what mission does this sort of module enable for DC?
My thought was for maintenance of satellites in LEO, the module would carry the replacement hardware, tools  possibly an airlock etc.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: adrianwyard on 03/20/2014 06:08 pm
It would be an extremely valuable satellite that could justify an Atlas V launch, and a throw-away mission module/air-lock. And as mentioned before you can't abort with the module attached (but then perhaps you could launch with it disconnected, and hard-mate once in orbit. This could be done for all towed packages)

In the press conference they mentioned add-on mission objectives to an ISS crew change flight which makes sense, but with this type of mission module attached you can't dock to the ISS.

I believe EVA on all spacecraft after the Shuttle requires putting everyone in suits and depressurising the entire cabin. This seems like a step backwards especially with larger crews. We're already in the realm of sci-fi speculation here, so how about building a suitport into the upper surface of the DC behind a mini payload bay door? That would make it reusable.

http://en.wikipedia.org/wiki/Suitport

But back to near-term reality: how strong is the case for satellite servicing missions at all? And if there is one, which of the proposed spacecraft is most suited?
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Elmar Moelzer on 03/20/2014 06:32 pm
And as mentioned before you can't abort with the module attached (but then perhaps you could launch with it disconnected, and hard-mate once in orbit.
I still don't get why you cant abort with it? It would detach from the DC in case of an abort, just like the interstage does now.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: adrianwyard on 03/20/2014 07:06 pm
If the module had an airlock, the connections to DC would be much more substantial than those to the interstage, i.e. a docking mechanism.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: BrightLight on 03/20/2014 07:15 pm
If the module had an airlock, the connections to DC would be much more substantial than those to the interstage, i.e. a docking mechanism.
Yes, I think you are correct, the stack would become "clumsy" - not impossible but a higher risk for aborts.  Also as you pointed out above, the missions would have to have very high value for this package to be worth while such as a Hubble class satellite.  At the costs for the module and associated LV etc., a unmanned tug and a maintenance depot might be a better choice in the long run?
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Elmar Moelzer on 03/20/2014 07:19 pm
If the module had an airlock, the connections to DC would be much more substantial than those to the interstage, i.e. a docking mechanism.
Got a point there, but then, the airlock would be closed during ascent and I could imagine most of the connections to be severed during launch. So how much more attached would it be than the interstage is?
I am not sure. I guess you are right though and it would be too much effort and too impractical.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: adrianwyard on 03/21/2014 01:41 am
At the costs for the module and associated LV etc., a unmanned tug and a maintenance depot might be a better choice in the long run?
That seems more credible to me, especially as many of the satellites are way up in geostationary orbit, which as far as we know DC can't get to. I'm not sure you'd want to spend the time/dV to return to a maintenance depot - just move the whole thing to where its needed with nice big SEP.

But then again, I'm not sure I believe there is a market for any kind of satellite servicing right now. And yet SNC continue to highlight this as a selling point for DC: http://www.popularmechanics.com/science/space/news/everything-you-need-to-know-about-dream-chaser-americas-next-space-plane-16610110

The success of Hubble repair/servicing is a tempting justification by precedent, but apart from another Hubble visit (unlikely) what actual mission might SNC propose DC for (i.e. one best accomplished with a manned vehicle) that would make sense to accountants?
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Ben the Space Brit on 03/21/2014 09:15 am
http://www.popularmechanics.com/_mobile/science/space/news/everything-you-need-to-know-about-dream-chaser-americas-next-space-plane-16610110?click=pm_news

That article says Dream Chaser has more pressurized volume than SpaceShuttle.

I find that *very* difficult to believe.

Well, without Spacelab modules, the Shuttle's pressured volume was basically the three decks in the forward module, forming close to a cube that must have been about 5-6m on each side. Dreamchaser's pressure vessel will be more-or-less cylindrical. Plug in the dimensions and it should be possible to figure out the truth of that claim.

FWIW, it never ceased to strike me about how small the Shuttle's habitation area (upper and mid decks) was for a vehicle that usually flew with 5-6 crew.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: BrianNH on 03/21/2014 12:04 pm
http://www.popularmechanics.com/_mobile/science/space/news/everything-you-need-to-know-about-dream-chaser-americas-next-space-plane-16610110?click=pm_news

Quote
I think we're probably the furthest ahead on the human spaceflight vehicle of the three companies.

So, all 3 companies think that they are in the lead.    :)
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: adrianwyard on 03/21/2014 03:58 pm
Copied from Update thread: http://forum.nasaspaceflight.com/index.php?topic=29416.msg1174802#msg1174802

"You do indeed get to ~16m^3 by assuming an average pressure vessel diameter of 5.5ft and a length of 24ft, which seems plausible. This compares to 10m^3 for Dragon."

...and compares to the Shuttle orbiter at ~74m^3.

There is going to be a difference in usable free interior volume and actual pressure vessel dimensions, but enough to support Mark Sirangelo's claim? Plenty of the Shuttle's crew compartment went to lockers, and the lower deck was not exactly crewed space like the upper and middeck.

Also, the HL-20 was tested with a crew of 10, so I think that alone suggests the 5.5ft average diameter must be for usable volume, not pressure vessel total.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: adrianwyard on 03/21/2014 04:19 pm
And as others have stated, the actual space in the Shuttle orbiter feels unexpectedly cramped when viewed in person.

If I plug in estimates of perceived unobstructed volume in the Shuttle, I get as low as 21m^3. (two decks, averaging 6ft tall, 8ft wide, and 8ft long).
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Lars_J on 03/21/2014 04:58 pm
The only way you could get even close is if you compared the *usable* volume of the Shuttle with the *total* volume of the DC. And Shuttle should still win.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Jim on 03/21/2014 05:12 pm
And as others have stated, the actual space in the Shuttle orbiter feels unexpectedly cramped when viewed in person.
.

But it isn't since in zero g, the whole volume can be used. 
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: adrianwyard on 03/21/2014 05:15 pm
And as others have stated, the actual space in the Shuttle orbiter feels unexpectedly cramped when viewed in person.
.

But it isn't since in zero g, the whole volume can be used. 
No doubt. The in-flight videos are testament to that.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: adrianwyard on 03/21/2014 05:23 pm
The only way you could get even close is if you compared the *usable* volume of the Shuttle with the *total* volume of the DC. And Shuttle should still win.
Well, math is math. If we assume the actual DC pressure vessel is just one foot wider than usable volume (i.e. 6 inches all round) then you get 22m^3 (rather than 16m^3 for 5.5ft). That is bigger than my perceived usable volume on STS. But why make an apples to oranges comparison anyway?

For those that haven't noticed, the DC crew compartment is most definitely substantially longer than the one on STS.

All of this is handwaving though because we just don't know how much of the DC pressure vessel is occupied by avionics/ECLSS etc. If STS is any guide it's a lot.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Lars_J on 03/21/2014 05:29 pm
While the cabin is long, DC is going to be very cramped. Look at the HL-20 mock-up below.

Imagine this, but with addition life support and flight systems hardware, and then add in pressure suits. It will *very* tight spaces.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: adrianwyard on 03/21/2014 05:38 pm
Right. That does look to be about the 5.5ft dimension we've been using (I found it in HL-20 documentation).

Now I think about it, the fact that our guesses for perceived clear volume on STS decks is close to the guess of total pressure vessel volume on DC makes me wonder if SNC PR have incorrectly made that comparison, hence Mark's claim?
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: adrianwyard on 03/21/2014 08:10 pm
Back to the plausibility of missions for DC beyond ISS crew rotation:

Does anyone know if the rear docking port can be used for EVA in addition to docking, i.e. opened to vacuum and opened/closed by someone in a space suit? The SIMAC opening is apparently 32" across with petals removed, which I'm guessing is wide enough.

I'm trying to determine if they're more likely to use the top hatch, or this rear port for EVA.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Rocket Science on 03/21/2014 10:27 pm
This is one area tha SNC sontinues to lead in with educational outreach...

From the PM article:

"wouldn't it be terrific if we brought America's space program to America? And instead of having people come to see the shuttle land in Florida or California, we could plan landings on our return trips to different places around the country where those states or the universities or the high schools could bring the students out and get to see the space program. And wouldn't that be a terrific thing to spark the next generation and education, if people could actually experience firsthand what space is like?"
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: adrianwyard on 03/22/2014 05:44 pm
So true. None of the other CC competitors have a spokesperson that communicates enthusiasm as well as Mark Sirangelo, especially when it comes to the touchy-feel inspirational dimension (which I understand non space-cadets relate to  ;)). And yet if I'm honest this actually makes me less confident about their chances of doing actual missions.  What they say often sounds just a little too good to be true. For example, I would happily drive across country to see a DC land, perhaps at an airshow or something. I can imagine the school-kids cheering! But realistically, how is that going to happen? Are a returning crew going to be happy to be diverted to an airshow? If it's an ISS flight, the crew could be deconditioned and need medical exams, etc.

The same goes for talk of satellite servicing missions, etc. I worry this is just the optimistic sales-pitch a company makes when they are in a cut-throat competition for scarce resources, which of course they are. The press conference with Teledyne Brown/MSFC, and the ESA/DLR one for that matter were extremely thin on details, and served primarily as an opportunity to pitch the 'sizzle' of SNC's project.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: adrianwyard on 03/22/2014 06:10 pm
Back to trying to understand how DC would be good for satellite servicing:

As far as I can tell any EVA in a stock DC would likely be through the top hatch as I can find no record of an EVA through a docking port like the one in the rear. (Perhaps it's too small, or has too many sharp edges, or is too difficult to operate in a spacesuit.)

This is a shame, because the unique form of the DC pressure vessel rather lends itself to a configuration with an interior airlock that opens to the rear hatch. Structurally you'd just need to place a bulkhead/hatch in the pressure vessel between the flight deck and the rear so you can depress just the rear section. I'm just assuming the structure can handle the new loads, etc.

There are a several reasons this would give DC an edge over the other CC projects (which would presumably depressurize the whole capsule):

a] It would allow for 'IVA' crew-members to assist, as is standard procedure for STS and ISS spacewalks. It's much easier to deal with checklists, cameras, robotics when in shirtsleeves.
b] Anything in the flight-deck section would not have to deal with vacuum conditions, esp. avionics/laptops, sealed food, etc.

But, my guess is this would require a DC to be customized with a special EVA hatch in the rear. We believe they will be changing out the docking port each flight, so this is not too far-fetched.

If we're customizing DC, then you could add a mini robot arm to this version, stored in the airlock, and taken outside and attached to a grapple fixture on the EVA hatch. It would be brought home too of course. Such an arm would be operated by the crew in the pressurized section.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: NealioSpace on 03/25/2014 08:58 pm
What is the status of human-rating the Atlas V that the DC will fly atop? Who is footing the cost for the human-rating?
Thanks,
Neal
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: A_M_Swallow on 03/25/2014 09:01 pm
What is the status of human-rating the Atlas V that the DC will fly atop? Who is footing the cost for the human-rating?
Thanks,
Neal

Payment to human-rate the Atlas V forms part of the money for CST-100 development.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Jim on 03/26/2014 12:19 am

Payment to human-rate the Atlas V forms part of the money for CST-100 development.

and ULA is getting money from DC
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Lars_J on 03/26/2014 01:54 am

Payment to human-rate the Atlas V forms part of the money for CST-100 development.

and ULA is getting money from DC

...and from CST-100 (Boeing) as well, I would assume. I wonder if they've negotiated a cost sharing agreement for this phase of CCDev.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: adrianwyard on 03/28/2014 06:36 pm
A few posts back I poked fun at SNC suggesting that DC could land around the country to increase public engagement with the space program. http://forum.nasaspaceflight.com/index.php?topic=29417.msg1175155#msg1175155

It's still a cool idea, and I still don't see how it's realistic. However, it did get me thinking "what if" along those public engagement lines.

Firstly, if we're not constrained by reality and your goal is to put on a spectacle to wow the public, rather than have DC glide to a silent landing (blink and it's over), have a SpaceX Crewed Dragon do a propulsive short hop. That would be a show! And would not happen because the risk to the public in the event of a mishap is pretty high (toxic propellant etc). I guess it might chew up the runway too.

But DC's propulsion is non-toxic, and not aimed downwards, so picture an airshow where for the finale, DC takes off under its own power, does a wide circuit, and lands where it started. That would be a show too. And perhaps not too much more dangerous than other airshow antics (jet powered trucks, etc).

To repeat, this is not meant to be a serious suggestion (we don't know if the DC can even rotate and get airborne under its own power) but it's certainly a fun idea so thought I'd share.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: mheney on 03/28/2014 09:19 pm
How well would a nose skid (as opposed to nose gear with a wheel) handle this?  You'd be looking at a landing (from space), take-off, then another landing on the skid.   Is that within the performance margins of the nose skid?
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: adrianwyard on 03/28/2014 09:27 pm
It's a question for sure, although there are harder ones such as: why would SNC risk such a valuable assert for a publicity stunt? In terms of the skid, I think the physics of the situation (lots of momentum) lead to it sliding qute easily once it gets going.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Zed_Noir on 03/29/2014 12:41 am
How well would a nose skid (as opposed to nose gear with a wheel) handle this?  You'd be looking at a landing (from space), take-off, then another landing on the skid.   Is that within the performance margins of the nose skid?

My guess is that the nose skid saves weight and avoid using up the Dreamchaser internal volume for landing gear storage with pressurized tires. Also avoids the landing gear get heated up during re-entry with a conventional nose wheel. But probably means the nose skid gets replace after each landing.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Lars_J on 04/10/2014 10:56 pm
According to this post in the update thread, http://forum.nasaspaceflight.com/index.php?topic=29416.msg1180496#msg1180496 , SNC is in talks about supporting the Houston space port, and potentially landing there.

Why? Has SNC lost their marbles? Or are they so desperate to be selected that they are trying to involve every NASA center and/or congressional district?

This seems like the same bonkers idea of landing DC around the country. Possible, yes. Practical, NO.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: rayleighscatter on 04/11/2014 12:21 am
At best, the ability to land astronauts or scientific payloads within a 5 minute drive of JSC might have appeal to some in NASA. At worst, it has no effect on their bid.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: rpapo on 04/11/2014 09:24 am
Frankly, I wouldn't think that landing a glider, where you cannot do a go-around and you block further landing traffic until you can be towed off the runway, would be a good idea at a commercial airport.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: jtrame on 04/11/2014 10:51 am
Frankly, I wouldn't think that landing a glider, where you cannot do a go-around and you block further landing traffic until you can be towed off the runway, would be a good idea at a commercial airport.

1.  No go around in Florida or California either.
2.  Tenants at Ellington are folks like NASA, the Coast Guard, Air National Guard, or business jets.  Not what we usually think of as commercial.
3.  As designed, DC could theoretically be towed off the main runway quickly.  Not hours of safeing like Shuttle.
4.  Routine space travel requires out of the box thinking.  This is forward thinking for something that likely is years in the future.
5.  If it survives the down select, first landings likely at Florida or California anyway.
6.  At this point, any publicity is good publicity, especially in Houston.  Especially with a juggernaut like Boeing waiting in the "wings."
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: ChrisWilson68 on 04/11/2014 11:16 am
Frankly, I wouldn't think that landing a glider, where you cannot do a go-around and you block further landing traffic until you can be towed off the runway, would be a good idea at a commercial airport.

If the glider corners well enough, a good pilot will be able to get it clear of the active runway before it comes to a stop.  It's like having your car run out of gas on a freeway near an exit -- your momentum carries you through the exit and safely off the freeway if you put on the brakes enough but not too much and steer correctly.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: wolfpack on 04/11/2014 01:41 pm

3.  As designed, DC could theoretically be towed off the main runway quickly.  Not hours of safeing like Shuttle.


Just because the RCS is non-toxic doesn't mean it's safe to "taxi" right up to the gate after wheels-stop. It's still a spacecraft loaded with residual prop. DC will take a page from Shuttle's convoy ops, I'd wager.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Lee Jay on 04/11/2014 03:06 pm
Frankly, I wouldn't think that landing a glider, where you cannot do a go-around and you block further landing traffic until you can be towed off the runway, would be a good idea at a commercial airport.

If the glider corners well enough, a good pilot will be able to get it clear of the active runway before it comes to a stop.  It's like having your car run out of gas on a freeway near an exit -- your momentum carries you through the exit and safely off the freeway if you put on the brakes enough but not too much and steer correctly.


Yeah, but DC doesn't have a steering wheel, just aero surfaces and differential braking.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Go4TLI on 04/11/2014 03:14 pm
Frankly, I wouldn't think that landing a glider, where you cannot do a go-around and you block further landing traffic until you can be towed off the runway, would be a good idea at a commercial airport.

If the glider corners well enough, a good pilot will be able to get it clear of the active runway before it comes to a stop.  It's like having your car run out of gas on a freeway near an exit -- your momentum carries you through the exit and safely off the freeway if you put on the brakes enough but not too much and steer correctly.


Yeah, but DC doesn't have a steering wheel, just aero surfaces and differential braking.

It doesn't matter anyway.  Ellington is not "commercial" in the same way that Hobby or Bush (the two airports in the Houston area) are where passenger/cargo flights are coming in and taking off every few minutes. 
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: jtrame on 04/11/2014 04:15 pm

3.  As designed, DC could theoretically be towed off the main runway quickly.  Not hours of safeing like Shuttle.


Just because the RCS is non-toxic doesn't mean it's safe to "taxi" right up to the gate after wheels-stop. It's still a spacecraft loaded with residual prop. DC will take a page from Shuttle's convoy ops, I'd wager.

You're right. Maybe it can be towed safely to a holding area just off the main runway and then safe the props.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Go4TLI on 04/11/2014 04:28 pm

3.  As designed, DC could theoretically be towed off the main runway quickly.  Not hours of safeing like Shuttle.


Just because the RCS is non-toxic doesn't mean it's safe to "taxi" right up to the gate after wheels-stop. It's still a spacecraft loaded with residual prop. DC will take a page from Shuttle's convoy ops, I'd wager.

You're right. Maybe it can be towed safely to a holding area just off the main runway and then safe the props.

Probably not.  There are a host of reasons why and none of them have to do with the prop system.  One of the main reasons is the main gear tires are going to be extremely warm.  Keep out zones will be established around them once landing team arrives.  They will be allowed to cool. 

While there, if possible - which is likely - get the crew out and perhaps any time-sensitive payloads.  In addition, there is likely a time limit running where the actual structure (what's below the TPS) will need some sort of of active cooling to keep it within the engineering limits for the structure so that thermal soak-back does not damage it. 

Once those conditions are satisfied it will likely be safe to tow. 

Difference from the orbiter is that the prop system was not "safed", other than the crew essentially turning it off, ground crews were looking for leaks or a build-up of toxic gases.  Same thing with the APUs once turned off.  There were other things associated with the active thermal control system but DC will not share these design traits. 
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: rayleighscatter on 04/11/2014 07:57 pm
It would also take a bit of time to have a crew walk the runway and look for any debris (a genuine concern for anything using a skid) that could damage other aircraft. But as others have pointed out Ellington also doesn't have the same constraints as commercial airports and can, for instance, close a runway for half a day.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: douglas100 on 04/11/2014 10:00 pm
I'm with Lars_J on this one: it's a bonkers idea. The only reason for landing anywhere except KSC would be weather diversion or emergency. The facilities to refurbish DC are in Florida. Landing anywhere else adds to turn around time and hence cost.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Lee Jay on 04/11/2014 10:15 pm

3.  As designed, DC could theoretically be towed off the main runway quickly.  Not hours of safeing like Shuttle.


Just because the RCS is non-toxic doesn't mean it's safe to "taxi" right up to the gate after wheels-stop. It's still a spacecraft loaded with residual prop. DC will take a page from Shuttle's convoy ops, I'd wager.

What makes it any more unsafe than an airline full of jet fuel?  The hybrids are certainly stable, as is the ethanol.  I'm guessing you're worried about the nitrous?

One thing SNC has said is that the crew can pretty much get right out the back after wheels-stop.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: docmordrid on 04/12/2014 12:30 am
Does Concorde Flight 4590 ring a bell? That was just jet fuel. Imagine the potential of a nitrous tank penetration.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Lurker Steve on 04/12/2014 12:59 am
I'm with Lars_J on this one: it's a bonkers idea. The only reason for landing anywhere except KSC would be weather diversion or emergency. The facilities to refurbish DC are in Florida. Landing anywhere else adds to turn around time and hence cost.

I don't think returning DC back to Florida is a huge deal. It appears fairly easy to pack it up on a flatbed trailer and drive it back home. I can't imagine transport costs would be a huge deal if they had to land someplace other than KSC.
 
It's not like they have the huge expense of the SCA to deal with.
 
 
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Lee Jay on 04/12/2014 01:11 am
Does Concorde Flight 4590 ring a bell? That was just jet fuel. Imagine the potential of a nitrous tank penetration.

Yeah, if there's an accident.  But you'd know that pretty much immediately.  And despite what happened with the Concorde, we still taxi airliners to the gate without external inspection.

Once DC is on aero surfaces, what would prevent them from burning and/or venting all the rest of the oxidizer so it landed pretty much inert?
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Rocket Science on 04/12/2014 09:38 pm
I would hesitate taxiing off the active runway at a high speed for she might end up doing a ground loop or on her side... :'(
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Excession on 04/13/2014 05:14 am

3.  As designed, DC could theoretically be towed off the main runway quickly.  Not hours of safeing like Shuttle.


Just because the RCS is non-toxic doesn't mean it's safe to "taxi" right up to the gate after wheels-stop. It's still a spacecraft loaded with residual prop. DC will take a page from Shuttle's convoy ops, I'd wager.

Landing airplanes have lots of fuel left over too, but they get taxi in on their own under power. What's so dangerous about Dream Chaser that prevents them from towing it off the runway?
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: A_M_Swallow on 04/13/2014 11:53 am
If the risk is dangerous gasses we can make the driver's cabin of the towing vehicle an airtight container.  Outside work can be performed in a simplified spacesuit.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: jtrame on 04/13/2014 12:54 pm
The SNC website indicates the a quick exit by the crew and experiments.  What we really need is some clarification by someone from SNC on the how quick they expect the tow vehicle and dolly to be able to hook up and remove the DC to a safe holding area that would allow the runway to re-open.  Taking into consideration the TPS temps, and the other issues.  1 hr, 2 hrs., 3 hrs., etc ?

We didn't bring this up-- we are only responding to the SNC apparent interest in the proposed Houston Spaceport.  How routine can operations actually be at a combination spaceport/ private airport?  If it's "bonkers," a lot of folks in Houston and at SNC seem to taking it seriously anyway.

KSC is already a spaceport and has the facilities and the best runway and a long history of vectoring a returning deadstick gliding spacecraft.  Including how that works together with commercial airlanes and traffic. That has to be a tremendous advantage.  I don't think anyone here is arguing that point at all.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Rocket Science on 04/13/2014 01:17 pm
Airports and runways are routinely closed all the time with advanced arrangements; examples being for air shows or for use as temporary race circuits. Having Dream Chaser sitting like a “queen” at the end of her rollout until she is good and ready to proceed is not big deal. About her overflying populated areas, well Shuttle did it as announced her arrival with her distinctive “double sonic” booms and I’m ready to hear the sound of “American Space” again...  8)
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: RanulfC on 04/14/2014 06:14 pm
Airports and runways are routinely closed all the time with advanced arrangements; examples being for air shows or for use as temporary race circuits. Having Dream Chaser sitting like a “queen” at the end of her rollout until she is good and ready to proceed is not big deal. About her overflying populated areas, well Shuttle did it as announced her arrival with her distinctive “double sonic” booms and I’m ready to hear the sound of “American Space” again...  8)

Just to be "clear" here, "airports-and-runways" are NOT "routinely" closed all the time! The "specified" airports-and-runways are NOT what most people think of when hearing the word "Airport" which tends to refer to active commercial facilties with hundreds of flights daily. You do NOT see JFK, SFO or other "airports" closed unless it is a real emergency because doing so would cause major disruptions in traffic.

This is the "problem" with talking about landing a spacecraft at a "commercial" airport that is often glossed-over :) The disscussed airport cited is not a "major" hub and can afford to have its runways and airspace "cleared" for the duration of the landing event. Compare McCarran airport in Las Vegas to, say, Wendover airport in Utah :)
https://www.mccarran.com/
http://en.wikipedia.org/wiki/Wendover_Airport

Which one could "afford" to shut down to allow landing of the DC? :)

Randy
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: jtrame on 04/14/2014 06:21 pm
Airports and runways are routinely closed all the time with advanced arrangements; examples being for air shows or for use as temporary race circuits. Having Dream Chaser sitting like a “queen” at the end of her rollout until she is good and ready to proceed is not big deal. About her overflying populated areas, well Shuttle did it as announced her arrival with her distinctive “double sonic” booms and I’m ready to hear the sound of “American Space” again...  8)

Just to be "clear" here, "airports-and-runways" are NOT "routinely" closed all the time! The "specified" airports-and-runways are NOT what most people think of when hearing the word "Airport" which tends to refer to active commercial facilties with hundreds of flights daily. You do NOT see JFK, SFO or other "airports" closed unless it is a real emergency because doing so would cause major disruptions in traffic.

This is the "problem" with talking about landing a spacecraft at a "commercial" airport that is often glossed-over :) The disscussed airport cited is not a "major" hub and can afford to have its runways and airspace "cleared" for the duration of the landing event. Compare McCarran airport in Las Vegas to, say, Wendover airport in Utah :)
https://www.mccarran.com/
http://en.wikipedia.org/wiki/Wendover_Airport

Which one could "afford" to shut down to allow landing of the DC? :)

Randy

Indeed, we are talking about 1 additional spaceport here, not every airport, not a string of spaceports.  Florida, California, and Texas.  At least that's what I was referring to. 

Houston would be a little different than Florida or California since it would be a private spaceport/ airport combination.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: docmordrid on 04/14/2014 06:22 pm
Given the number of designated spaceport projects, some at existing airports, quite a few should be avalable.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Rocket Science on 04/15/2014 08:36 am
Airports and runways are routinely closed all the time with advanced arrangements; examples being for air shows or for use as temporary race circuits. Having Dream Chaser sitting like a “queen” at the end of her rollout until she is good and ready to proceed is not big deal. About her overflying populated areas, well Shuttle did it as announced her arrival with her distinctive “double sonic” booms and I’m ready to hear the sound of “American Space” again...  8)

Just to be "clear" here, "airports-and-runways" are NOT "routinely" closed all the time! The "specified" airports-and-runways are NOT what most people think of when hearing the word "Airport" which tends to refer to active commercial facilties with hundreds of flights daily. You do NOT see JFK, SFO or other "airports" closed unless it is a real emergency because doing so would cause major disruptions in traffic.

This is the "problem" with talking about landing a spacecraft at a "commercial" airport that is often glossed-over :) The disscussed airport cited is not a "major" hub and can afford to have its runways and airspace "cleared" for the duration of the landing event. Compare McCarran airport in Las Vegas to, say, Wendover airport in Utah :)
https://www.mccarran.com/
http://en.wikipedia.org/wiki/Wendover_Airport

Which one could "afford" to shut down to allow landing of the DC? :)

Randy
Hi Randy,
Long time no speak...  :) Active runways are as a routinely closed for other reasons such as for construction/maintenance for long periods of time. Shorter times are for security for the President and Air Force One. As far as airports totally being shut down for special events for the examples I mentioned, never held those major events such as Cleveland and St. Petersburg. I agree with the ones you cited since they seem closed on the best of days...  ;D If you have parallel runways you can close just one temporarily for a landing. We just never did one for a commercial spacecraft before... "Brave new world"? ;)

Regards
Robert
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Lurker Steve on 04/15/2014 12:38 pm
Given the number of designated spaceport projects, some at existing airports, quite a few should be avalable.

Do we know how long of a runway DC needs ?
How long are the runways at these fledgling spaceports ?

I'm sure the SLF at KSC is extra long, and Mohave and/or Edwards have long runways.
What about the one in Colorado ?
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Lee Jay on 04/15/2014 12:46 pm
Given the number of designated spaceport projects, some at existing airports, quite a few should be avalable.

Do we know how long of a runway DC needs ?

They've said nearly all airports designed for airliners have runways that are suitable.  To me, that means something in the 7-8000 foot range, but that's just a guess.

Quote
How long are the runways at these fledgling spaceports ?

I'm sure the SLF at KSC is extra long, and Mohave and/or Edwards have long runways.
What about the one in Colorado ?

They're 8000 feet.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: RanulfC on 04/17/2014 03:28 pm
Hi Randy,
Long time no speak...  :)

Howdy! Been around just not that active :)

Quote
Active runways are as a routinely closed for other reasons such as for construction/maintenance for long periods of time. Shorter times are for security for the President and Air Force One. As far as airports totally being shut down for special events for the examples I mentioned, never held those major events such as Cleveland and St. Petersburg. I agree with the ones you cited since they seem closed on the best of days...  ;D If you have parallel runways you can close just one temporarily for a landing. We just never did one for a commercial spacecraft before... "Brave new world"? ;)

One other thing to remember is that the DC has a front SKID, that's not going to go over well on most commercial runway in and of itself :)

The "key" factor is finding a commercial airport that CAN afford to shut down for landing with suitable "alternates" around the flight path to allow an abort if required. The main concern is that since DC is an "upowered" vehicle in the landing patterns it has "right-of-way" over all "powered" traffic and the "airport" has to be able to ensure constant control over the airspace. All you need is someone with an ultra-light wanting to "buzz-the-tower" during a DC landing run :)

At the same time you do not want to disrupte the airlines landing schedules because they have a LOT more clout than you do and lawyers they are willing and able to use if you do :) So you either want a "dedicated" (Mojave, etc) airport/spaceport, or you want it "out-of-the-way" to normal air traffic as much as possible.

Randy
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: ChefPat on 05/03/2014 02:12 pm
How long of a runway does Dream Chaser need?
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Elmar Moelzer on 05/04/2014 12:18 am
How long of a runway does Dream Chaser need?

Look two posts up:
They've said nearly all airports designed for airliners have runways that are suitable.  To me, that means something in the 7-8000 foot range, but that's just a guess.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: dror on 05/04/2014 05:25 am
Theoretically, can a Falcon 9 lift a DC or is it in the range of a falcon heavy only?
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Lars_J on 05/04/2014 06:09 am
Theoretically, can a Falcon 9 lift a DC or is it in the range of a falcon heavy only?

Yes. F9 matches the Atlas V to LEO with 0 or 1 SRBs.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: dror on 05/04/2014 06:44 am
And is DC planed to use any srbs?
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: docmordrid on 05/04/2014 07:21 am
It uses an Atlas V 402, so no.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Lars_J on 05/04/2014 08:06 am
It uses an Atlas V 402, so no.

Actually, we have seen wind tunnel models of DC in a 412 configuration (1 srb), but it should still be possible.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: dror on 05/04/2014 11:22 am
Thanks!
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: yg1968 on 05/04/2014 02:07 pm
How long of a runway does Dream Chaser need?

They said anywhere a 737 can land, DC can land.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: deltaV on 05/04/2014 07:47 pm
They said anywhere a 737 can land, DC can land.

According to http://www.boeing.com/assets/pdf/commercial/airports/acaps/737.pdf (starting at page 270) various 737 models take 5000-7000 feet to land at sea level on a wet runway with flaps 30 and max landing weight.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: adrianwyard on 05/09/2014 05:51 pm
Steve Lindsey specifies 8000ft runway in video here:

http://forum.nasaspaceflight.com/index.php?topic=29416.msg1196113#msg1196113
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: yg1968 on 05/15/2014 03:17 pm
SNC's Roth also mentions they are in talks with companies who might offer DC for high-speed point-to-point suborbital flights starting with air-launch. (Listen at ~53min).

This has come up before, and the consensus was it's problematic at best. At a minimum it involves the development of an expendable boost stage - which must not land in someone's garden. Then there's the problem of the launch aircraft (presumably VG is still keeping WK2 to themselves). Routes would likely be limited and so this would be more of an expensive thrill-ride than a replacement for air travel.

Could DC use the first stage of a Falcon 9 as a boost stage for high-speed point-to-point suborbital flights?
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: adrianwyard on 05/15/2014 03:39 pm
I think if you want a point-to-point scenario that adds up energy-wise this is the sort of thing you have to do.

But this requires a very hand-wavy rose-tinted future when reusable F9Rs are cheap to use, everyone's happy to start their journey in Florida, and the facilities there have been modified to handle this new vehicle config with no second stage...

But yesterday SNC's John Roth mentioned air-launch. Without a booster in addition to the hybrid motors on DC, it's not going to get much further than SpaceShipTwo.

Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Lee Jay on 05/15/2014 03:45 pm
I think if you want a point-to-point scenario that adds up energy-wise this is the sort of thing you have to do.

But this requires a very hand-wavy rose-tinted future when reusable F9Rs are cheap to use, everyone's happy to start their journey in Florida, and the facilities there have been modified to handle this new vehicle config with no second stage...

But yesterday SNC's David Roth mentioned air-launch. Without a booster in addition to the hybrid motors on DC, it's not going to get much further than SpaceShipTwo.

How about Stratolaunch, perhaps with just one or two stages?
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: adrianwyard on 05/15/2014 04:11 pm
I bet you're right; if you want to air-launch DC for point-to-point then Stratolaunch is the best fit. (Which is also a paper airplane at the moment.)

Interestingly, I just realized they mention carrying manned spacecraft in their promo video:

https://www.youtube.com/watch?v=YgJFKUiuDBE

I wonder if the 385 foot wingspan would limit your starting runway options. And of course starting locations are still limited by the need to dispose of the booster (unless we also invent a fly-back booster).

But a bigger question is: what market would all this tech development serve?
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: docmordrid on 05/15/2014 04:31 pm
Upper income folks and assuming short turnarounds opportunitistic time-critical like transplants.

Stratolaunch will be using the Shuttle Landing Facility at KSC, at least initially.

http://www.floridatoday.com/story/news/local/2014/05/04/nasa-applies-shuttle-strip-permit/8710067/
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Lars_J on 05/15/2014 04:34 pm
Point to point transportation with DC makes absolutely no sense. Whatsoever.

People seem to forget that to get somewhere useful - like intercontinental or coast to coast point-to-point - you practically need near orbital velocity.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: adrianwyard on 05/15/2014 04:44 pm
I agree it looks that way, but SNC's John Roth (VP Business Development) mentioned it yesterday. Hence the discussion.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: TomH on 05/15/2014 05:39 pm
I don't see this discussed upthread anywhere, and I want this issue to remain DC centric. At this point, DC is in jeopardy of losing its LV. This is not the place to discuss RD-180, geopolitics, lawsuits, or any of that stuff. Nevertheless, one potential casualty of those issues is that DC's ability to continue in commercial crew competition is particularly imperilled.

CST-100's most logical move is to DIV, though the expense rises. F9/Dragon is unaffected. If worse comes to worst, DC has to look toward the more expensive DIV or see if SpaceX is willing to consider a competing spacecraft having a potential ride on its LV. Boeing and SNC both have money already invested in man rating AV. I really don't know to what extent Boeing could pull strings for ULA to apply credit toward man rating DIV. My guess is they might have a little more leverage toward making that happen than SNC, but perhaps doing it for one and not the other might be ruled unfair in court.

So the questions are these? What does SNC do about an LV if AV becomes unavailable? What does SNC do if it seriously begins looking like AV might become unavailable? What kind of proactive/preleminary things should SNC be doing right now? In the commercial crew competition, is it fair/unfair for DC and CST-100 to score lower due to the AV situation? These question are about DC only. We all know the background from other threads. Please do not discuss RD-180, Russia, or lawsuits here.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: BrightLight on 05/15/2014 05:44 pm
I don't see this discussed upthread anywhere, and I want this issue to remain DC centric. At this point, DC is in jeopardy of losing its LV. This is not the place to discuss RD-180, geopolitics, lawsuits, or any of that stuff. Nevertheless, one potential casualty of those issues is that DC's ability to continue in commercial crew competition is particularly imperilled.

CST-100's most logical move is to DIV, though the expense rises. F9/Dragon is unaffected. If worse comes to worst, DC has to look toward the more expensive DIV or see if SpaceX is willing to consider a competing spacecraft having a potential ride on its LV. Boeing and SNC both have money already invested in man rating AV. I really don't know to what extent Boeing could pull strings for ULA to apply credit toward man rating DIV. My guess is they might have a little more leverage toward making that happen than SNC, but perhaps doing it for one and not the other might be ruled unfair in court.

So the questions are these? What does SNC do about an LV if AV becomes unavailable? What does SNC do if it seriously begins looking like AV might become unavailable? What kind of proactive/preleminary things should SNC be doing right now? In the commercial crew competition, is it fair/unfair for DC and CST-100 to score lower due to the AV situation? These question are about DC only. We all know the background from other threads. Please do not discuss RD-180, Russia, or lawsuits here.
In the end, their must be an integrated stack - If the AV is not available an alternative LV must be found.  If it turns out to be a Delta LV, costs go up (way up) and scores for the DC will most likely go down.  If Falcon can be used for the DC, costs go down but I can't say the scores for the DC go up.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: adrianwyard on 05/15/2014 05:50 pm
Actually, this was (mistakenly) discussed on the Update thread just yesterday:

http://forum.nasaspaceflight.com/index.php?topic=29416.msg1198805#msg1198805

From what I've read on NSF human rating DIV is not seriously considered as too many design margins are below what's needed.

From an armchair physics POV, putting DC on F9 looks possible (and John Roth of SNC mentioned it yesterday) although an awful lot of wind tunnel testing was done on Atlas/Centaur. I don't know how much of that would be applicable to DC on F9, if any.

It seems more believable that DC would fly on a SpaceX LV than Boeing would put their CST-100 on an F9, which gives SNC the advantage.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: arachnitect on 05/15/2014 06:16 pm
Actually, this was (mistakenly) discussed on the Update thread just yesterday:

It seems more believable that DC would fly on a SpaceX LV than Boeing would put their CST-100 on an F9, which gives SNC the advantage.


Boeing satellites are manifested to fly on Falcon. Boeing has said for years that CST will fly on whatever LV makes the most sense.

Both Boeing and SNC have to survive CCtCap (with Atlas V) first.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: adrianwyard on 05/15/2014 06:28 pm
It's a fair point. And if AV future is a question-mark and/or F9 is cheaper, switching CST-100 to F9 might be what it takes to bump out a competitor in the downselect.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: BrightLight on 05/15/2014 06:31 pm
It's a fair point. And if AV future is a question-mark and/or F9 is cheaper, switching CST-100 to F9 might be what it takes to bump out a competitor in the downselect.
while their could be several (2 to 3) spacecraft options, we will have been reduced to one LV.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: TomH on 05/15/2014 06:33 pm
Anybody see any possibility at all that either Boeing or SNC might investigate Liberty? It would need either the steel solids line reopened or the SLS advanced booster developed. Either would take time. Would both be overpowered?
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Elmar Moelzer on 05/15/2014 06:46 pm
It's a fair point. And if AV future is a question-mark and/or F9 is cheaper, switching CST-100 to F9 might be what it takes to bump out a competitor in the downselect.
It also sounds like a perfect bureaucratic move by a government agency. It would contract two competitors while down selecting to one system ;)
And I am not seeing this as a bad thing, in this case, even though I would probably favor the F9 + Dream Chaser combination.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: adrianwyard on 05/15/2014 06:58 pm
If only one LV was available I'd be inclined to take the next step and downselect to just one crewed vehicle too. Part of the value of maintaining competition is it gives you redundancy, i.e. if something catastrophic shows up during development of one LV+Vehicle combination, you still have the other. (And if you're lucky, both will make it to market and so you'd have redundancy during the operational period too.)

If you know for certain you'd only have F9, then the benefit of maintaining a competition is substantially lessened. And SpaceX would presumably be in a position to offer a lower cost solution given they'd provide the whole system, so F9+DragonRider would look like the best option.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: BrightLight on 05/15/2014 07:04 pm
If only one LV was available I'd be inclined to take the next step and downselect to just one crewed vehicle too. Part of the value of maintaining competition is it gives you redundancy, i.e. if something catastrophic shows up during development of one LV+Vehicle combination, you still have the other. (And if you're lucky, both will make it to market and so you'd have redundancy during the operational period too.)

If you know for certain you'd only have F9, then the benefit of maintaining a competition is substantially lessened. And SpaceX would presumably be in a position to offer a lower cost solution given they'd provide the whole system, so F9+DragonRider would look like the best option.
I'm inclined to agree with you however a monopoly is rarely a good thing, as we have seen with the Russian crew seat price - classic economics of supply and demand.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: adrianwyard on 05/15/2014 07:06 pm
Agreed. And DC certainly has merits as a complement to Dragon. I wonder if any money at all would be saved at this point by committing to just F9 and ceasing human-rating AV and dev/testing the Dual Engine Centaur.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: A_M_Swallow on 05/15/2014 07:11 pm
An alternative way ahead for SNC is to ask the Europeans to man rate the Ariane.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: BrightLight on 05/15/2014 07:12 pm
Agreed. And DC certainly has merits as a complement to Dragon. I wonder if any money at all would be saved at this point by committing to just F9 and ceasing human-rating AV and dev/testing the Dual Engine Centaur.
I am a big fan of DC but you bring up a good point, putting the majority of funds into Falcon/Dragon with a smaller risk reduction "pot" into (my favorite) DC might make the best sense - as DC is a different vehicle altogether from a capsule.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: adrianwyard on 05/15/2014 07:16 pm
An alternative way ahead for SNC is to ask the Europeans to man rate the Ariane.
Just so long as they remember to add hinges to DCs fins so it fits under the fairing... But seriously, do you mean launch Commercial Crew flights from Korou, or have Ariane available to launch additional DC missions?
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: adrianwyard on 05/15/2014 07:18 pm
To muddy the waters further: I bet SNC and SpaceX could commit to lower prices if they were guaranteed all of the ISS Crew flights. Until other uses for these vehicles materialize the flight-rate/utilization is going to be low. Here again SpaceX have an advantage as their vehicle can be used for ISS cargo.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Star One on 05/15/2014 07:43 pm
Agreed. And DC certainly has merits as a complement to Dragon. I wonder if any money at all would be saved at this point by committing to just F9 and ceasing human-rating AV and dev/testing the Dual Engine Centaur.

No way to my mind should human space flight just rest on the F9, the whole point of this to get away from the monopoly launcher position not to go straight from one to another.

Hopefully the AV can get through this current tricky position to stop this highly undesirable position occurring.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: A_M_Swallow on 05/15/2014 10:30 pm
An alternative way ahead for SNC is to ask the Europeans to man rate the Ariane.
Just so long as they remember to add hinges to DCs fins so it fits under the fairing... But seriously, do you mean launch Commercial Crew flights from Korou, or have Ariane available to launch additional DC missions?

A good question for last week.  That would be quite a long dog leg to get to the ISS, unless they launched from Europe.

This week.  The Bigelow spacestations may be orbits that are easier to get to from Korou.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: baldusi on 05/16/2014 02:53 am

An alternative way ahead for SNC is to ask the Europeans to man rate the Ariane.
Just so long as they remember to add hinges to DCs fins so it fits under the fairing... But seriously, do you mean launch Commercial Crew flights from Korou, or have Ariane available to launch additional DC missions?

A good question for last week.  That would be quite a long dog leg to get to the ISS, unless they launched from Europe.

This week.  The Bigelow spacestations may be orbits that are easier to get to from Korou.

Are you aware that Kourour has direct launch from 5deg to 97deg? And Ariane 5 already launches the ATV without dogleg to the ISS?
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: A_M_Swallow on 05/16/2014 06:14 am

An alternative way ahead for SNC is to ask the Europeans to man rate the Ariane.
Just so long as they remember to add hinges to DCs fins so it fits under the fairing... But seriously, do you mean launch Commercial Crew flights from Korou, or have Ariane available to launch additional DC missions?

A good question for last week.  That would be quite a long dog leg to get to the ISS, unless they launched from Europe.

This week.  The Bigelow spacestations may be orbits that are easier to get to from Korou.

Are you aware that Kourour has direct launch from 5deg to 97deg? And Ariane 5 already launches the ATV without dogleg to the ISS?

It all depends on the mass.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: TrevorMonty on 05/16/2014 10:25 am
Excluding AV, in the near term F9 looks likes DCs only option for a LV.  One issue with using the Ariane 5 is that a large chunk of the money NASA would be paying SNC for CC missions would go off shore. Long term OrbitalATK may build a LV the DC could fly on.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Rocket Science on 05/17/2014 02:41 pm
I started a thread on Human Rating of Delta IV if you're interested.

http://forum.nasaspaceflight.com/index.php?topic=34753.0
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Rocket Science on 05/19/2014 07:39 pm
Note the nozzle design on the model...
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: adrianwyard on 05/19/2014 09:05 pm
Note the nozzle design on the model...

Anyone have any ideas on what's driving that design? I had a wild guess last year:

http://forum.nasaspaceflight.com/index.php?topic=29416.msg1100270#msg1100270
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Halidon on 05/19/2014 10:58 pm


I never get tired of that Fuzzy dice shot.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: TomH on 05/24/2014 12:56 am
I don't see this discussed upthread anywhere, and I want this issue to remain DC centric. At this point, DC is in jeopardy of losing its LV. This is not the place to discuss RD-180, geopolitics, lawsuits, or any of that stuff. Nevertheless, one potential casualty of those issues is that DC's ability to continue in commercial crew competition is particularly imperilled.

CST-100's most logical move is to DIV, though the expense rises. F9/Dragon is unaffected. If worse comes to worst, DC has to look toward the more expensive DIV or see if SpaceX is willing to consider a competing spacecraft having a potential ride on its LV. Boeing and SNC both have money already invested in man rating AV. I really don't know to what extent Boeing could pull strings for ULA to apply credit toward man rating DIV. My guess is they might have a little more leverage toward making that happen than SNC, but perhaps doing it for one and not the other might be ruled unfair in court.

So the questions are these? What does SNC do about an LV if AV becomes unavailable? What does SNC do if it seriously begins looking like AV might become unavailable? What kind of proactive/preleminary things should SNC be doing right now? In the commercial crew competition, is it fair/unfair for DC and CST-100 to score lower due to the AV situation? These question are about DC only. We all know the background from other threads. Please do not discuss RD-180, Russia, or lawsuits here.
In the end, their must be an integrated stack - If the AV is not available an alternative LV must be found.  If it turns out to be a Delta LV, costs go up (way up) and scores for the DC will most likely go down.  If Falcon can be used for the DC, costs go down but I can't say the scores for the DC go up.

Well, in light of this development:

http://forum.nasaspaceflight.com/index.php?topic=34810.0

either AV pursues a new engine it can acquire quickly, like TR-107, or DC will be looking for a new ride.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: rayleighscatter on 05/24/2014 02:54 pm
Dreamchaser isn't a national security satellite.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: TomH on 05/24/2014 09:35 pm
Dreamchaser isn't a national security satellite.

That is obviously the case, however if RD-180 is no longer available for national security payloads, I do not think LM/ULA will continue to build/offer an RD-180 version just for commercial payloads. Do you?

This means AV gets a new engine or AV production will end. TR-107 and RS-84 are possible replacements, however other modifications would need to be made, pushing the new AV several years into the future, too late for use by commercial crew. The license to domestically produce RD-180 expires in 2020 or 2022 (sources disagree), therefore it makes little sense to set up a line that will have to be shut down shortly thereafter. I would not be surprised to see all AVs currently manifested for commercial use legally requisitioned for national security purposes.

All this places commercial users of AV in a difficult position. Any new engine for AV is so far into the future that CST-100 or DC will not have a chance in commercial crew. Delta IV is more expensive, needs man rating, and other modifications would be required (tower, etc.). This would seem to give F9-Dragon Rider an immense advantage, although if Russia instigates a 2020 shutdown of ISS, it may all be for naught anyway.

SpaceX may have little interest in offering their rocket to other spacecraft when they have their own spacecraft to ride on their rocket.

Commercial Crew, DC and CST-100 in particular, are in a difficult position right now. Even if the destination (ISS) is still there, it appears that the ride for DC and CST-100 may well be in serious jeopardy.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: RonM on 05/24/2014 09:50 pm
SpaceX may have little interest in offering their rocket to other spacecraft when they have their own spacecraft to ride on their rocket.

Business is business. If DC or CST-100 needs a lift uphill, SpaceX would be more than happy to oblige and take their money. It's just another payload from another paying customer.

If NASA or someone else prefers DC or CST-100 to Dragon for a mission, why wouldn't SpaceX want to get the contract for the launch? At least they would be making some money off of it.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Jim on 05/24/2014 09:59 pm

That is obviously the case, however if RD-180 is no longer available for national security payloads, I do not think LM/ULA will continue to build/offer an RD-180 version just for commercial payloads. Do you?


Yes, because it includes NASA payloads. 


Commercial Crew, DC and CST-100 in particular, are in a difficult position right no


No, they are not.   If national security payloads left Atlas, it would be easier for commercial crew
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: TomH on 05/25/2014 01:45 am
SpaceX may have little interest in offering their rocket to other spacecraft when they have their own spacecraft to ride on their rocket.

Business is business. If DC or CST-100 needs a lift uphill, SpaceX would be more than happy to oblige and take their money. It's just another payload from another paying customer.

If NASA or someone else prefers DC or CST-100 to Dragon for a mission, why wouldn't SpaceX want to get the contract for the launch? At least they would be making some money off of it.

This is opinion only, but I disagree. As I understand it, the spacecraft will not compete by themselves; they will compete already having an agreement with an LV. The competition will evaluate the spacecraft and LV as a combination. If DC and CST-100 have no other LV capable of launching them, SpaceX could refuse to offer F9. At that point, the only spacecraft with a human rated appropriate LV would be Dragon Rider. This would give SPaceX an opportunity to assure that both their spacecraft and their booster would be chosen.

An example of business is business not fitting is when DirecTV refused to allow Dish Network to advertise via DirecTV broadcast. DTV could have taken Dish's money, but by not doing so, they kept their competitors at bay. The feds intervened and forced DTV to air Dish advertisements against their will. I do not know if Boeing and SNC have some way of suing or filing a grievance that would force SX to make F9 available to competitors or not
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: rayleighscatter on 05/25/2014 01:54 am

That is obviously the case, however if RD-180 is no longer available for national security payloads, I do not think LM/ULA will continue to build/offer an RD-180 version just for commercial payloads. Do you?
So long as LM/ULA has the capability to build them, and as long as people are willing to pay them to build them, I'm sure some kind of accord will be found.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: TomH on 05/25/2014 01:59 am

That is obviously the case, however if RD-180 is no longer available for national security payloads, I do not think LM/ULA will continue to build/offer an RD-180 version just for commercial payloads. Do you?


Yes, because it includes NASA payloads. 


Commercial Crew, DC and CST-100 in particular, are in a difficult position right no


No, they are not.   If national security payloads left Atlas, it would be easier for commercial crew

Jim,

What is your epistemology? Is this your opinion or can you offer specific support for this position? To me, it would seem more likely that all AVs already reserved by commercial users would more likely be appropriated in the name of national security in order to buy time for a new engine to be developed for the national security launches.

Let's say that the US and Russian governments both gave continued approval for RD-180 to remain available for non-national security launches and LM wanted still to offer it. In that it would no longer be being used as part of the EELV program, would it now be offered to commercial users via LM, or still through ULA?
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: TomH on 05/25/2014 02:08 am

That is obviously the case, however if RD-180 is no longer available for national security payloads, I do not think LM/ULA will continue to build/offer an RD-180 version just for commercial payloads. Do you?
So long as LM/ULA has the capability to build them, and as long as people are willing to pay them to build them, I'm sure some kind of accord will be found.

And that could be true. My fear is that if NRO/DoD can't get any new ones, they might declare an emergency that grants them the right to appropriate all the AVs currently in the que. This might mean CC corporations would have to wait until a later batch of RD-180s come along that are forbidden to NRO/DoD. By the time those are available, CC competition is farther down the road, and only SpaceX was able to offer a spacecraft and qualified LV together at time for flight testing. This might not be the case, but I fear it could. Very recently Orion's first test launch on DIVH got bumped by a DoD launch that had a higher priority.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: RonM on 05/25/2014 02:54 am
SpaceX may have little interest in offering their rocket to other spacecraft when they have their own spacecraft to ride on their rocket.

Business is business. If DC or CST-100 needs a lift uphill, SpaceX would be more than happy to oblige and take their money. It's just another payload from another paying customer.

If NASA or someone else prefers DC or CST-100 to Dragon for a mission, why wouldn't SpaceX want to get the contract for the launch? At least they would be making some money off of it.

This is opinion only, but I disagree. As I understand it, the spacecraft will not compete by themselves; they will compete already having an agreement with an LV. The competition will evaluate the spacecraft and LV as a combination. If DC and CST-100 have no other LV capable of launching them, SpaceX could refuse to offer F9. At that point, the only spacecraft with a human rated appropriate LV would be Dragon Rider. This would give SPaceX an opportunity to assure that both their spacecraft and their booster would be chosen.

An example of business is business not fitting is when DirecTV refused to allow Dish Network to advertise via DirecTV broadcast. DTV could have taken Dish's money, but by not doing so, they kept their competitors at bay. The feds intervened and forced DTV to air Dish advertisements against their will. I do not know if Boeing and SNC have some way of suing or filing a grievance that would force SX to make F9 available to competitors or not

Ah, but your example shows the feds intervened. If necessary, so would NASA.

We're getting pretty hypothetical here, to the point of being unreasonable, but let's keep playing with the idea. If NASA picked Dream Chaser over Dragon and Atlas V was unavailable, it would be unwise for SpaceX to refuse to provide F9 launches. SpaceX would be refusing the rented payload of their best customer, NASA. That's a bad business move.

Getting back to reality, Dream Chaser would be a commercial launch and ULA could still get the engines for an Atlas V.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: docmordrid on 05/25/2014 03:09 am
Maybe, maybe not. Also posted to Space Policy;

Aviation Week's article quotes an anonymous industry insider who says Atlas V is toast, then goes on at length about possible scenarios. Covers lots of turf.

http://m.aviationweek.com/space/support-grows-new-us-rocket-engine (http://"http://m.aviationweek.com/space/support-grows-new-us-rocket-engine")

Quote
>
The Atlas V always the less expensive of ULAs fleet (partly owing to the Russian engine sourcing), the most competitive in the commercial market, and the nearest peer to Space Exploration Technologies (SpaceX) new Falcon family is effectively over, an industry source says. This longtime player in the space industry preferred talking on background. The convergence of a Russian threat to cut off RD-180 supply, SpaceXs impending certification to compete with the Falcon 9v1.1 and the lawsuit filed by SpaceX April 28 claiming ULAs sole-source deal with the U.S. Air Force was anticompetitive has put so much pressure on the Atlas V that it is unlikely to survive, the source says.
>
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: RonM on 05/25/2014 03:25 am
OK, maybe DC on F9 isn't so hypothetical after all.

We are living in interesting times.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: docmordrid on 05/25/2014 03:55 am
When you step back and imagine the long view the pressure on Atlas V (and Delta IV) is only going to increase; Falcon Heavy, an EELV class Antares (ATK core + RL-10's), the possibility of Blue Origin's booster, etc.  Even Thunderbolt for lighter payloads. Time marches on.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: TomH on 05/25/2014 05:09 am
Ah, but your example shows the feds intervened. If necessary, so would NASA.

NASA doesn't have the authority to intervene the way the FCC does and the way courts do. It may happen and it may not.

Getting back to reality, Dream Chaser would be a commercial launch and ULA could still get the engines for an Atlas V.

Is it possible to have an adult discussion without condescension?
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Star One on 05/25/2014 09:12 am

When you step back and imagine the long view the pressure on Atlas V (and Delta IV) is only going to increase; Falcon Heavy, an EELV class Antares (ATK core + RL-10's), the possibility of Blue Origin's booster, etc.  Even Thunderbolt for lighter payloads. Time marches on.

Yes ULA must be very concerned about these mostly hypothetical launchers.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: woods170 on 05/26/2014 06:56 am
Maybe, maybe not. Also posted to Space Policy;

Aviation Week's article quotes an anonymous industry insider who says Atlas V is toast, then goes on at length about possible scenarios. Covers lots of turf.

http://m.aviationweek.com/space/support-grows-new-us-rocket-engine (http://"http://m.aviationweek.com/space/support-grows-new-us-rocket-engine")

Quote
>
The Atlas V always the less expensive of ULAs fleet (partly owing to the Russian engine sourcing), the most competitive in the commercial market, and the nearest peer to Space Exploration Technologies (SpaceX) new Falcon family is effectively over, an industry source says. This longtime player in the space industry preferred talking on background. The convergence of a Russian threat to cut off RD-180 supply, SpaceXs impending certification to compete with the Falcon 9v1.1 and the lawsuit filed by SpaceX April 28 claiming ULAs sole-source deal with the U.S. Air Force was anticompetitive has put so much pressure on the Atlas V that it is unlikely to survive, the source says.
>
Way too premature to even suggest Atlas V is toast. Just another AVweek failure IMO.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: JAFO on 05/26/2014 09:58 am
Way too premature to even suggest Atlas V is toast. Just another AVweek failure IMO.

AvWeek has become MROWeek.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Prober on 06/04/2014 10:43 am
When you step back and imagine the long view the pressure on Atlas V (and Delta IV) is only going to increase; Falcon Heavy, an EELV class Antares (ATK core + RL-10's), the possibility of Blue Origin's booster, etc.  Even Thunderbolt for lighter payloads. Time marches on.

yeah, too many launchers in the pipeline and not enough launches =?
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: bad_astra on 06/05/2014 04:32 am
yeah, too many launchers in the pipeline and not enough launches =?

That's often been the case, but that makes the case against the current EELV's even more critical. They have little to no commercial market, and if more competitive commercial launchers arrive (and in the post-Falcon IX world, it's somewhat funny to still see the cynical crowd scoff at the idea. They might as well adjust their monocles and exclaim "Such insolence"! ) and manage to get certified, there will be nothing but pork and campaign contributions to keep them going.

But I think any move from Atlas V has to be way down the road. SNC is going to launch on Atlas V, and AvLeak is probably no more correct about Atlas V's demise then it was about Blackstar (the magic fairy dust spaceplane, not the respected NSF poster) in orbit.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: adrianwyard on 06/19/2014 08:26 pm
SNC to use ORBITEC green propellant RCS thrusters on DC:

http://www.sncorp.com/press_more_info.php?id=617

Anyone know about these?

They might be gaseous methane/oxygen:

http://arc.aiaa.org/doi/abs/10.2514/6.2011-5835
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Ronsmytheiii on 06/19/2014 08:32 pm
SNC to use ORBITEC green propellant RCS thrusters on DC:

http://www.sncorp.com/press_more_info.php?id=617

Anyone know about these?

More importantly

Quote
ORBITEC is the lead for the Environmental Control and Life Support Systems (ECLSS) and Thermal Control Systems (TCS) for SNC, providing reliable living conditions including temperature and humidity control to support the astronauts during their journeys on SNC's Dream Chaser® spacecraft. [\quote]
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: JasonAW3 on 06/19/2014 08:56 pm
Personally, I wouldn't be suprised if NASA chooses BOTH Dream Chaser and the Dragon/Falcon 9 combos for the Crewed space craft.

Each craft has different advantages and disadvantages.  Acting as a BEO crew served craft, (Possibly starting as a cargo craft for the L-2 Space Station everyone seems enamored of) the Dragon appears that it should be able to handle the faster reentry speeds of BEO missions.

The Dream Chaser has the advantage of a lower Gee reentry and a much broader crossrange than a ballistic capsule.

While the Orion appears to be NASA's primary choice for BEO missions, I suspect lower costs will likely make the Dragon the go to craft for the "Transport Missions" while the Orion will be more for the initial exploration missions.  Sort of the difference between a 2.5 ton Military truck versus the Special Forces ATV dune buggy.

The Dreamchaser would be more like an ambulance or a VIP shuttle, as it's not really designed for BEO missions.

Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: arachnitect on 06/19/2014 09:26 pm
SNC to use ORBITEC green propellant RCS thrusters on DC:

http://www.sncorp.com/press_more_info.php?id=617

Anyone know about these?

They might be gaseous methane/oxygen:

http://arc.aiaa.org/doi/abs/10.2514/6.2011-5835

I've seen references to N20/Ethanol but someone on the forum recently said it's cold gas. I thought Aerojet was doing the RCS?
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: adrianwyard on 06/20/2014 05:24 pm
Agreed; the only supplier I've seen mentioned for RCS to date has been Aerojet, but evidently that's now changed. There are still plenty of unknowns here.

ORBITEC have tested larger versions of their engine tech (30K lbf). That's not sufficient to replace the hybrids (which we guess are about 50K lbf) but it does match the hybrid RocketMotorOne used on SpaceShipOne.

I expect this acquisition will be received well by those who are twitchy about SNC's reliance on hybrids.

More here: http://www.parabolicarc.com/2012/09/27/orbitec-tests-new-vision-rocket-engine/
http://www.orbitec.com/documents/ORBITEC_Rocket_Launch_Test_Mojave.pdf

Flight video: http://www.parabolicarc.com/2012/10/26/orbitecs-rocket-engine-soars-above-the-mojave-desert/
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: rcoppola on 06/21/2014 01:12 am
Personally, I wouldn't be suprised if NASA chooses BOTH Dream Chaser and the Dragon/Falcon 9 combos for the Crewed space craft...(Trimmed)

Totally agree. I also think both DC and Dragon will be chosen.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Lar on 06/21/2014 03:08 am
Personally, I wouldn't be suprised if NASA chooses BOTH Dream Chaser and the Dragon/Falcon 9 combos for the Crewed space craft...(Trimmed)

Totally agree. I also think both DC and Dragon will be chosen.
I would adore this outcome.  But I don't see what basis exists to think that. Government is just too inept. I see a downselect to CST as a distinct possibility. Or at best one of the other two. Both is a lot to hope for.

So convince me... why won't there be a downselect?
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: M_Puckett on 06/21/2014 03:35 am
No redundancy in a sole-source provider.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: adrianwyard on 06/21/2014 04:28 am
No redundancy in a sole-source provider.

A year ago I think many would argue a downselect to a single CC provider would still leave the Soyuz as the redundant backup option... Who knows if the desire for independent redundancy is actually sufficient to fund more than one Commercial Crew provider.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Star One on 06/21/2014 09:52 am

Personally, I wouldn't be suprised if NASA chooses BOTH Dream Chaser and the Dragon/Falcon 9 combos for the Crewed space craft...(Trimmed)

Totally agree. I also think both DC and Dragon will be chosen.

When one of the players is Boeing I personally wouldn't bet against them.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: arachnitect on 06/21/2014 06:17 pm
Personally, I wouldn't be suprised if NASA chooses BOTH Dream Chaser and the Dragon/Falcon 9 combos for the Crewed space craft...(Trimmed)

Totally agree. I also think both DC and Dragon will be chosen.
I would adore this outcome.  But I don't see what basis exists to think that. Government is just too inept. I see a downselect to CST as a distinct possibility. Or at best one of the other two. Both is a lot to hope for.

So convince me... why won't there be a downselect?

Why is a downselect "inept?" CST is a good product and can do everything NASA has asked for.

That said, anything could happen:

DC gives a lot of people at NASA a warm fuzzy feeling, and NASA has fought hard to keep throwing money at it.

SNC is pushing hard for a CRS2 contract in a way that Boeing isn't. The CRS2 requirements aren't really favorable to either CST or DC, but of the two vehicles DC has more to offer in a resupply role (more capacity supposedly, favorable reentry loads). So there's another way DC could make it to ISS.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Lar on 06/21/2014 06:29 pm
Why is a downselect "inept?" CST is a good product and can do everything NASA has asked for.

In my view CST is the least capable and most expensive vehicle of the 3. But because of how government works and how Boeing works, it is the most likely to survive. Things don't survive on technical merits. That's inept.

All MHO of course.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: vt_hokie on 06/21/2014 11:12 pm
If the orbital spacecraft currently under construction by all three contenders make it to completion, that will be quite interesting.  Can it be assumed that regardless of future downselect decisions, the DC OTV will make its test flight?  It would be hard to see throwing away that capability once it becomes a bird in hand. 
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Jim on 06/22/2014 12:27 pm

In my view CST is the least capable and most expensive vehicle of the 3. But because of how government works and how Boeing works, it is the most likely to survive. Things don't survive on technical merits. That's inept.

1.  You don't know that it is least capable.  Have you evaluated it against the requirements?  What says it doesn't meet the requirements better than the others?
2.  How do you know it is more expensive?
3.  And because the gov't selects the vehicle that best meets its requirements, how is that inept?  Inept, posts that make unsupported claims and are nothing but biased.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: baldusi on 06/22/2014 10:47 pm
I assumed that the questions on the CRS2 QA about L+1hr capability was from SNC, but couldn't have been done by Dragon v2? If that becomes a "desirable" requirement, then SNC and SpaceX would be able to offer such capability.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Coastal Ron on 06/22/2014 11:45 pm

In my view CST is the least capable and most expensive vehicle of the 3. But because of how government works and how Boeing works, it is the most likely to survive. Things don't survive on technical merits. That's inept.

1.  You don't know that it is least capable.  Have you evaluated it against the requirements?  What says it doesn't meet the requirements better than the others?
2.  How do you know it is more expensive?
3.  And because the gov't selects the vehicle that best meets its requirements, how is that inept?  Inept, posts that make unsupported claims and are nothing but biased.

Yes, the details of the proposals that Boeing, Sierra Nevada and SpaceX submitted would not be public, and all we know are the pricing comments from Elon Musk and what Bigelow has said are their prices they are charging for accessing their private stations.

And I agree also that NASA has had a good track record recently of picking winners based on requirements, and that they have had logical requirements.

Personally I think that Boeing has the least "interesting" vehicle of the three, but Boeing is a very capable company and they seem to have designed a good vehicle.

If NASA is looking for the least risky route to having at least two operational vehicles, then Boeing is likely to be one of them.  But if NASA feels good about SpaceX being a safe choice, and would like to take some risk to add a horizontal lander, then Boeing is likely to be left out.

Definitely an embarrassment of riches...
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: TrevorMonty on 06/23/2014 03:13 am
Selection is not only about the space vehicle but also LV.

F9 has yet to prove it's self but long term supply shouldn't be an issue and with 2 years at least till something flys I would hope any technical issues are resolved with F9.
Atlas is better bet with excellent flight history but long term supply is now in doubt.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Lar on 06/23/2014 04:02 am

In my view CST is the least capable and most expensive vehicle of the 3. But because of how government works and how Boeing works, it is the most likely to survive. Things don't survive on technical merits. That's inept.

1.  You don't know that it is least capable.  Have you evaluated it against the requirements?  What says it doesn't meet the requirements better than the others?
2.  How do you know it is more expensive?
3.  And because the gov't selects the vehicle that best meets its requirements, how is that inept?  Inept, posts that make unsupported claims and are nothing but biased.

I prefaced with "in my view"... not claiming certainty. 1) What I've seen of CST as an outsider doesn't impress me. Airbags? Please. Both the other vehicles are likely to be reusable with less work. 2) As for cost, Dragon already launches on F9 which is the cheaper launcher. I doubt very much that Boeing can convert CST cheaply. 3) If the government selects the least capable and most expensive vehicle (that is, if we assume my 1 and 2 are true) then yes, that IS inept. Sure, if I'm wrong about 1 and 2 and CST is the most capable, cheapest vehicle, then selecting it would not be inept. But that's not the way to bet.. Boeing and LockMart don't do cheap any more.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: dror on 06/23/2014 05:03 am
Lets say nasa decides to invest in all three competitors in order to reduce launch prices through increased competition.
How much money is needed for the seconed and third competitors?
What will be the impact of having three competitors on the final prices?
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: guckyfan on 06/23/2014 07:13 am
Lets say nasa decides to invest in all three competitors in order to reduce launch prices through increased competition.
How much money is needed for the seconed and third competitors?
What will be the impact of having three competitors on the final prices?

Less flights per competitor, higher cost. Competition driving down prices requires a certain volume unless competitors are willing to sell below cost.

What influence competition? With CST-100 I don't know but would not be surprised if price goes up without competition.

With Dream Chaser and Dragon, they both want to be attractive for potential commercial customers so won't up their prices IMO.

I doubt that in the present situation competition will lower prices. The only justification could be maintaining a backup provider.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Star One on 06/23/2014 07:46 am

Lets say nasa decides to invest in all three competitors in order to reduce launch prices through increased competition.
How much money is needed for the seconed and third competitors?
What will be the impact of having three competitors on the final prices?

Less flights per competitor, higher cost. Competition driving down prices requires a certain volume unless competitors are willing to sell below cost.

What influence competition? With CST-100 I don't know but would not be surprised if price goes up without competition.

With Dream Chaser and Dragon, they both want to be attractive for potential commercial customers so won't up their prices IMO.

I doubt that in the present situation competition will lower prices. The only justification could be maintaining a backup provider.

Surely Boeing has already shown it wants to attract commercial customers as much as the other two?
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: guckyfan on 06/23/2014 10:11 am

Surely Boeing has already shown it wants to attract commercial customers as much as the other two?

Then why unlike the other two do they declare to opt out if they are not selected?
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Prober on 06/23/2014 02:23 pm

In my view CST is the least capable and most expensive vehicle of the 3. But because of how government works and how Boeing works, it is the most likely to survive. Things don't survive on technical merits. That's inept.

1.  You don't know that it is least capable.  Have you evaluated it against the requirements?  What says it doesn't meet the requirements better than the others?
2.  How do you know it is more expensive?
3.  And because the gov't selects the vehicle that best meets its requirements, how is that inept?  Inept, posts that make unsupported claims and are nothing but biased.

I prefaced with "in my view"... not claiming certainty. 1) What I've seen of CST as an outsider doesn't impress me. Airbags? Please. Both the other vehicles are likely to be reusable with less work. 2) As for cost, Dragon already launches on F9 which is the cheaper launcher. I doubt very much that Boeing can convert CST cheaply. 3) If the government selects the least capable and most expensive vehicle (that is, if we assume my 1 and 2 are true) then yes, that IS inept. Sure, if I'm wrong about 1 and 2 and CST is the most capable, cheapest vehicle, then selecting it would not be inept. But that's not the way to bet.. Boeing and LockMart don't do cheap any more.

Airbags proven off the shelf technology (if you drive a car you put your trust in it)

What makes you think SpaceX can manufacture cheaper than Boeing?
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Rocket Science on 06/23/2014 02:38 pm

In my view CST is the least capable and most expensive vehicle of the 3. But because of how government works and how Boeing works, it is the most likely to survive. Things don't survive on technical merits. That's inept.

1.  You don't know that it is least capable.  Have you evaluated it against the requirements?  What says it doesn't meet the requirements better than the others?
2.  How do you know it is more expensive?
3.  And because the gov't selects the vehicle that best meets its requirements, how is that inept?  Inept, posts that make unsupported claims and are nothing but biased.

I prefaced with "in my view"... not claiming certainty. 1) What I've seen of CST as an outsider doesn't impress me. Airbags? Please. Both the other vehicles are likely to be reusable with less work. 2) As for cost, Dragon already launches on F9 which is the cheaper launcher. I doubt very much that Boeing can convert CST cheaply. 3) If the government selects the least capable and most expensive vehicle (that is, if we assume my 1 and 2 are true) then yes, that IS inept. Sure, if I'm wrong about 1 and 2 and CST is the most capable, cheapest vehicle, then selecting it would not be inept. But that's not the way to bet.. Boeing and LockMart don't do cheap any more.

Airbags proven off the shelf technology (if you drive a car you put your trust in it)

What makes you think SpaceX can manufacture cheaper than Boeing?
Bad day to make the "air bag" point today Prober... Big recall from Toyota, Honda and Mazda... Just saying... ;D
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: newpylong on 06/24/2014 01:07 am

In my view CST is the least capable and most expensive vehicle of the 3. But because of how government works and how Boeing works, it is the most likely to survive. Things don't survive on technical merits. That's inept.

1.  You don't know that it is least capable.  Have you evaluated it against the requirements?  What says it doesn't meet the requirements better than the others?
2.  How do you know it is more expensive?
3.  And because the gov't selects the vehicle that best meets its requirements, how is that inept?  Inept, posts that make unsupported claims and are nothing but biased.

I prefaced with "in my view"... not claiming certainty. 1) What I've seen of CST as an outsider doesn't impress me. Airbags? Please. Both the other vehicles are likely to be reusable with less work. 2) As for cost, Dragon already launches on F9 which is the cheaper launcher. I doubt very much that Boeing can convert CST cheaply. 3) If the government selects the least capable and most expensive vehicle (that is, if we assume my 1 and 2 are true) then yes, that IS inept. Sure, if I'm wrong about 1 and 2 and CST is the most capable, cheapest vehicle, then selecting it would not be inept. But that's not the way to bet.. Boeing and LockMart don't do cheap any more.

Ya lost me here. There is no data to back any of this up.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Elmar Moelzer on 06/24/2014 02:35 pm
I think that NASA needs to look ahead further. Even assuming the ISS is discontinued, it makes sense for NASA to think of future LEO destinations and work and plan their vehicle selection with that in mind. SLS and Orion alone just wont do much (too expensive in the long run and IMHO a technological dead end).
And if they keep an eye on the more distant future in LEO, then CST 100 makes the least sense of all.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: arachnitect on 06/24/2014 03:33 pm
I think that NASA needs to look ahead further. Even assuming the ISS is discontinued, it makes sense for NASA to think of future LEO destinations and work and plan their vehicle selection with that in mind. SLS and Orion alone just wont do much (too expensive in the long run and IMHO a technological dead end).
And if they keep an eye on the more distant future in LEO, then CST 100 makes the least sense of all.


What evaluation criteria are you proposing?
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Lar on 06/25/2014 06:51 pm

In my view CST is the least capable and most expensive vehicle of the 3. But because of how government works and how Boeing works, it is the most likely to survive. Things don't survive on technical merits. That's inept.

1.  You don't know that it is least capable.  Have you evaluated it against the requirements?  What says it doesn't meet the requirements better than the others?
2.  How do you know it is more expensive?
3.  And because the gov't selects the vehicle that best meets its requirements, how is that inept?  Inept, posts that make unsupported claims and are nothing but biased.

I prefaced with "in my view"... not claiming certainty. 1) What I've seen of CST as an outsider doesn't impress me. Airbags? Please. Both the other vehicles are likely to be reusable with less work. 2) As for cost, Dragon already launches on F9 which is the cheaper launcher. I doubt very much that Boeing can convert CST cheaply. 3) If the government selects the least capable and most expensive vehicle (that is, if we assume my 1 and 2 are true) then yes, that IS inept. Sure, if I'm wrong about 1 and 2 and CST is the most capable, cheapest vehicle, then selecting it would not be inept. But that's not the way to bet.. Boeing and LockMart don't do cheap any more.

Ya lost me here. There is no data to back any of this up.

I thought Atlas launch prices were public record, at least that's what I recall ULA claiming. Those prices are more than F9 prices. That takes care of 2. As for 1, there's no data to back up an assertion in either direction, AFAICT, so it's just an opinion. We all have opinions. Time will tell, or maybe the specs will never be released in sufficient detail to make the determination.

As for 3, it's basic logic. If you choose something that is less capable and costs more (assume 1 and 2 turn out to be true), you're inept... not sure how to make it clearer.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Coastal Ron on 06/25/2014 07:09 pm
I thought Atlas launch prices were public record, at least that's what I recall ULA claiming.

I think what ULA is claiming is not that their prices are public per se (i.e. listed on their website like SpaceX does), but that their customers have transparency into how they price.  Of course the U.S. Government is by far their largest customer, and even the U.S. Government has complained about ULA's lack of transparency, so to say the least there is still disagreement over this issue.  At most we all know what the U.S. Government releases after they have awarded a contract, and that generally doesn't have a lot of detail beyond the gross numbers - the recent Block Buy is a good example of that.

I've spent a lot of time trying to uncover pricing information, but it's been pretty hard to come up with any consistent numbers for Atlas V or Delta IV.  And that's been part of the complaint against ULA, is that they obfuscate what their real costs are (something they have to disclose with government contracts) which allows them to change their pricing from contract to contract.

I'm not sure I've seen any information on what SNC is paying for their launch on Atlas V - has anyone heard what the price is?  Would be interesting to compare that to what the Block Buy price is.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: sghill on 06/25/2014 07:15 pm
As for 3, it's basic logic. If you choose something that is less capable and costs more (assume 1 and 2 turn out to be true), you're inept... not sure how to make it clearer.

Or, you've got a "best value" favorite already picked out.

Sorry, I don't mean that to sound cynical.  We all have best value choices in life that make little sense on a spreadsheet, but which give us a sense that we're getting exactly what we sought to pay for.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: newpylong on 06/26/2014 12:04 am

In my view CST is the least capable and most expensive vehicle of the 3. But because of how government works and how Boeing works, it is the most likely to survive. Things don't survive on technical merits. That's inept.

1.  You don't know that it is least capable.  Have you evaluated it against the requirements?  What says it doesn't meet the requirements better than the others?
2.  How do you know it is more expensive?
3.  And because the gov't selects the vehicle that best meets its requirements, how is that inept?  Inept, posts that make unsupported claims and are nothing but biased.

I prefaced with "in my view"... not claiming certainty. 1) What I've seen of CST as an outsider doesn't impress me. Airbags? Please. Both the other vehicles are likely to be reusable with less work. 2) As for cost, Dragon already launches on F9 which is the cheaper launcher. I doubt very much that Boeing can convert CST cheaply. 3) If the government selects the least capable and most expensive vehicle (that is, if we assume my 1 and 2 are true) then yes, that IS inept. Sure, if I'm wrong about 1 and 2 and CST is the most capable, cheapest vehicle, then selecting it would not be inept. But that's not the way to bet.. Boeing and LockMart don't do cheap any more.

Ya lost me here. There is no data to back any of this up.

I thought Atlas launch prices were public record, at least that's what I recall ULA claiming. Those prices are more than F9 prices. That takes care of 2. As for 1, there's no data to back up an assertion in either direction, AFAICT, so it's just an opinion. We all have opinions. Time will tell, or maybe the specs will never be released in sufficient detail to make the determination.

As for 3, it's basic logic. If you choose something that is less capable and costs more (assume 1 and 2 turn out to be true), you're inept... not sure how to make it clearer.

You don't have to try to make it clearer because you can't - it's all unknown. Just because Atlas V costs X amount on the market and Falcon costs X amount means nothing when it comes down to what might be in the proposal to NASA. It also doesn't matter if Dragon can do A-Z and CST can only do A-F if NASA is only looking for A-D.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Todd Martin on 06/26/2014 03:01 am
Boeing's CST100 is designed to be re-usable, they say 10 flights.  Dreamchaser & Dragonrider are also designed to handle at least 10 flights per vehicle.

The cost for 10 launches is then 10 Launch Vehicles and 1 Space-craft.  Yes, it is a bit more complicated since there are re-furbishment costs and perhaps SpaceX can begin to reuse their 1st stage for commercial crew.  Nevertheless, it should be clear that the launch vehicle costs dominate in the pricing game for commercial crew.

SpaceX Falcon 9 is the cheapest.  They have the advantage.
Atlas V 401 (no solid boosters) are used by DreamChaser.
Atlas V 421 (2 solid boosters) are used by CST100.

I don't see how Boeing has any chance of winning the competition based on price.  An Atlas V 421 HAS to be the most expensive Launch vehicle and therefore the Boeing bid HAS to be the highest bid.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Robotbeat on 06/26/2014 03:08 am
We still don't know how much money it will take SNC to get all the bugs out of the hybrid system or switch to liquid propellants. That may be a sizable chunk of change. The CST-100 and Dragon don't have such question marks (Dragon v2 CAN still do splash-down if that's really the determining factor). My assumption (which you're free to disagree with) here is that SNC will have headaches similar to Virgin Galactic when they finally get to doing actual testing with hybrids on the spacecraft itself.

But both the Dragon and the CST-100 have fairly straight-forward abort systems, easier in many ways than Orion's abort system, even though they are a little more novel design (Orion's abort system is nearly the mass of the capsule!).

I wish Dreamchaser all the luck in the world, just skeptical about the hybrid propulsion part.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: adrianwyard on 06/26/2014 03:28 am
FYI both CST-100 and Dream Chaser are expected to use a Dual Engine Centaur, so the last digit should be 2 (i.e. 402, and 422). And that extra RL-10 will not come for free.

Boeing's CST100 is designed to be re-usable, they say 10 flights.  Dreamchaser & Dragonrider are also designed to handle at least 10 flights per vehicle.

The cost for 10 launches is then 10 Launch Vehicles and 1 Space-craft.  Yes, it is a bit more complicated since there are re-furbishment costs and perhaps SpaceX can begin to reuse their 1st stage for commercial crew.  Nevertheless, it should be clear that the launch vehicle costs dominate in the pricing game for commercial crew.

SpaceX Falcon 9 is the cheapest.  They have the advantage.
Atlas V 401 (no solid boosters) are used by DreamChaser.
Atlas V 421 (2 solid boosters) are used by CST100.

I don't see how Boeing has any chance of winning the competition based on price.  An Atlas V 421 HAS to be the most expensive Launch vehicle and therefore the Boeing bid HAS to be the highest bid.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: arachnitect on 06/26/2014 04:25 am
FYI both CST-100 and Dream Chaser are expected to use a Dual Engine Centaur, so the last digit should be 2 (i.e. 402, and 422). And that extra RL-10 will not come for free.

Boeing's CST100 is designed to be re-usable, they say 10 flights.  Dreamchaser & Dragonrider are also designed to handle at least 10 flights per vehicle.

The cost for 10 launches is then 10 Launch Vehicles and 1 Space-craft.  Yes, it is a bit more complicated since there are re-furbishment costs and perhaps SpaceX can begin to reuse their 1st stage for commercial crew.  Nevertheless, it should be clear that the launch vehicle costs dominate in the pricing game for commercial crew.

SpaceX Falcon 9 is the cheapest.  They have the advantage.
Atlas V 401 (no solid boosters) are used by DreamChaser.
Atlas V 421 (2 solid boosters) are used by CST100.

I don't see how Boeing has any chance of winning the competition based on price.  An Atlas V 421 HAS to be the most expensive Launch vehicle and therefore the Boeing bid HAS to be the highest bid.

We also now suspect that DC is flying on a 412 with one SRB.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Ike17055 on 06/26/2014 08:37 am

[/quote]
. If you choose something that is less capable and costs more (assume 1 and 2 turn out to be true), you're inept... not sure how to make it clearer.
[/quote]


Unless, it matches the specs better, which in this case may well be the true. Cost is secondary in the procurement process.  "Less capable" may equate to less risk, which is a prime goal of this undertaking.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: CJ on 06/30/2014 08:07 am
The launch abort system for Dream Chaser worries me a bit, and now I see this;

We also now suspect that DC is flying on a 412 with one SRB.

Dream Chaser, per the article by Chris Gebhardt; http://www.nasaspaceflight.com/2012/06/sierra-nevadas-5-year-partnership-nasa-progress-dream-chaser/ (http://www.nasaspaceflight.com/2012/06/sierra-nevadas-5-year-partnership-nasa-progress-dream-chaser/) relies on the Atlas 5 for thrust termination in case of an abort, but that's impossible while a SRB is firing, so if they do use the 412, that sounds like a major issue to me. The SRB also adds very sudden and violent failure modes.

A further concern I have for Dream Chaser is what happens after an abort? For much of the launch trajectory, it doesn't appear (to me, anyway) that the Dream Chaser would have sufficient Delta/v to reach land, and therefor would have to ditch. Would this be a survivable event?

Also, I've searched high and low and can't seem to find thrust numbers for the hybrid engines. Does anyone have any idea what they are? I'm trying to figure out if Dream Chaser could pull away from a still-thrusting stack (Such as in the case of a failed flight control system on the LV) and also figure out what kind of intrinsic Delta/v it has available in case of an abort.   
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: baldusi on 06/30/2014 12:31 pm
A single SRB give a T/W of less than 1 during all its firing time. Just close the RD-180 LOX valve and abort. No big issue.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: rpapo on 06/30/2014 03:46 pm
A single SRB give a T/W of less than 1 during all its firing time. Just close the RD-180 LOX valve and abort. No big issue.
But then with no main, controllable (throttle/gimbal) motor running, the SRB will be firing off-center.  Wouldn't the rocket tend to go into a spiral then?
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: JasonAW3 on 06/30/2014 04:47 pm
The launch abort system for Dream Chaser worries me a bit, and now I see this;

We also now suspect that DC is flying on a 412 with one SRB.

Dream Chaser, per the article by Chris Gebhardt; http://www.nasaspaceflight.com/2012/06/sierra-nevadas-5-year-partnership-nasa-progress-dream-chaser/ (http://www.nasaspaceflight.com/2012/06/sierra-nevadas-5-year-partnership-nasa-progress-dream-chaser/) relies on the Atlas 5 for thrust termination in case of an abort, but that's impossible while a SRB is firing, so if they do use the 412, that sounds like a major issue to me. The SRB also adds very sudden and violent failure modes.

A further concern I have for Dream Chaser is what happens after an abort? For much of the launch trajectory, it doesn't appear (to me, anyway) that the Dream Chaser would have sufficient Delta/v to reach land, and therefor would have to ditch. Would this be a survivable event?

Also, I've searched high and low and can't seem to find thrust numbers for the hybrid engines. Does anyone have any idea what they are? I'm trying to figure out if Dream Chaser could pull away from a still-thrusting stack (Such as in the case of a failed flight control system on the LV) and also figure out what kind of intrinsic Delta/v it has available in case of an abort.   

I remember NASA had a version of the HL-20 that they planned to land via a parasail parachute.  I suspect that the Dreamchaser might still retain that capibility incase of a lower than flightspeed abort scenerio.  While it would add mass, it would make the craft that much safer.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: mheney on 06/30/2014 05:06 pm
A single SRB give a T/W of less than 1 during all its firing time. Just close the RD-180 LOX valve and abort. No big issue.
But then with no main, controllable (throttle/gimbal) motor running, the SRB will be firing off-center.  Wouldn't the rocket tend to go into a spiral then?

Yes.  That's why you abort (and leave the stack behind.)   The point was that Dream Chaser can out-accelerate an Atlas V with the RD-180s shut down ...
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: adrianwyard on 06/30/2014 05:45 pm
Under the right conditions I could see the pitching moment from a single SRB actually increasing the distance between a separated DC and the first stage.

There's a great deal we don't know here which makes this just wild speculation.
+ No SRBs or one. Most visualizations show none, but they've wind tunnel tested a config with one. I suppose this could be to provide data just in case DC's weight unexpectedly outgrows the 402 config...
+ Specs of hybrid motors: Best guess is 2x 50K lbf, but as low as 2x 16K lbf. Their online info says up to 70K but that doc is two years old: http://www.sncspace.com/pdfs/Propulsion%20Systems_FINAL_web.pdf
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Rocket Science on 07/01/2014 11:34 am
Under the right conditions I could see the pitching moment from a single SRB actually increasing the distance between a separated DC and the first stage.

There's a great deal we don't know here which makes this just wild speculation.
+ No SRBs or one. Most visualizations show none, but they've wind tunnel tested a config with one. I suppose this could be to provide data just in case DC's weight unexpectedly outgrows the 402 config...
+ Specs of hybrid motors: Best guess is 2x 50K lbf, but as low as 2x 16K lbf. Their online info says up to 70K but that doc is two years old: http://www.sncspace.com/pdfs/Propulsion%20Systems_FINAL_web.pdf
Pad and first stage aborts usually need to pull about about 7-8g’s for safe separation...
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Prober on 07/01/2014 09:51 pm
now for an odd ball question.

Could you keep the RL-10's prechilled at launch. and separate the 2nd stage with a quick fire in an emergency?

Then go to DC sep. at a later point?




Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Rocket Science on 07/01/2014 10:48 pm
now for an odd ball question.

Could you keep the RL-10's prechilled at launch. and separate the 2nd stage with a quick fire in an emergency?

Then go to DC sep. at a later point?
The mass of the Centaur and Dream Chaser are about 75,000 pounds fueled so not really enough oomph to do it and it would take about 2 seconds for start-up of the engines which is valuable time...
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: CJ on 07/01/2014 11:50 pm
Pad and first stage aborts usually need to pull about about 7-8g’s for safe separation...

It looks to me as if, if the old specs of 70,000 lbf per engine are still applicable, Dreamchaser, with a mass of about 13 metric tons (28660 lb) could get  4.8 G off the pad. The way I calculated this was to divide the total thrust (140,000 lbs) by the vehicle mass, getting 4.88. If I messed up, I'd very much appreciate a correction (on this, or anything else). 

If, say, the true thrust of each engine is 50k, then it'd be 3.38 G. If it's 16k per, it'd be 1.1 G (and at 1 G, it'd just be sitting there making a lot of smoke and noise, due to gravity). 1.1 G would be pretty much useless for a pad abort, and totally useless for a thrusting LV, or at velocity in atmosphere.

Even the top end figure, 4,88 G, looks a bit low for comfort to me if you're dealing with a failing LV at 3G accel, because you'd have only a 1.8 G differential (and you'd be going nowhere if near MaxQ, even with the lower LV accel at that phase). 

I do agree that a fairly high G is needed for some abort scenarios (especially if there's a SRB on the stack) but I don't see how DC can do it. I hope I'm wrong.  On the flip side, Shuttle had no LAS at all (unless you count the SR-71 ejection seats of the first 4 flights, and good luck surviving those when the SRBs were firing) and NASA was fine with that - then.

Anyone have any idea about the throttle-up time for the hybrid engines? I'm assuming they must have addressed this issue (slow thrust ramp up) because it's unsuitable for LAS, but I'm curious as to how. 

now for an odd ball question.

Could you keep the RL-10's prechilled at launch. and separate the 2nd stage with a quick fire in an emergency?

Then go to DC sep. at a later point?

Hrmmm. Interesting idea. My guess would be that the mass is too high, so let's see. Dreamchaser, 28660 lb. Upper stage of the Atlas 5 with 2 RL-10 (Centaur), ballpark mass 50876 lbs, so a total of  79,536 lbs fully fueled. Total thrust of the two RL10s, 44,600 lbf (Wikipedia is wrong about the 2-engine Centuar, its figures assume one engine). 
That's far less than a 1 to 1 thrust ratio (so it'd give you less than one G) so IMHO, not viable for any abort scenario other than a failed first stage (with thrust terminating shutdown) at a point where Dreamchaser lacks the internal Delta/V to get to a runway (for example, when the trajectory would otherwise terminate in mid Atlantic). In that case, it might be theoretically viable.

Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: baldusi on 07/03/2014 02:35 am
Atlas V can cut thrust pretty fast. Probably T/W<1 after 1s, even with one SRB.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Comga on 07/08/2014 10:29 pm
The press release (http://forum.nasaspaceflight.com/index.php?topic=29416.msg1224029#msg1224029) on the propulsion review was careful to exclude all technical discussions. It says "Patented" but not "hybrid". Zero mention of the fuels.
That seems curious.
One can also see how hard it would be for SNC to switch at this point to a liquid fueled abort engine.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: rayleighscatter on 07/09/2014 12:51 am
But they are still calling it a motor.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Comga on 07/09/2014 02:20 am
But they are still calling it a motor.
That's the point.
They haven't changed fuels or controls, but they no longer see it as a selling point.
Once upon a time it was "Clever hybrid motors.  The ease of solid fuel.  The control of liquid engines." etc. etc.
Now it's just the limited technology they started with, and have passed all the NASA reviews with. 
There have been remarkable new liquid rocket engines in the last few years.  New generations of Merlin.  XCor's pump fed engines.  Newton, BE-3.  SNC's engine doesn't seem so cutting edge anymore.
That doesn't say they won't work.  SNC is just not touting it as an advantage.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: BrightLight on 07/10/2014 06:23 pm
I'm not sure if this has been reported:
As of 2012

"Currently, according to Zamprelli, the ORBITEC hybrid ECLSS has demonstrated approximately 84 percent closure (water and oxygen) at the time of the workshop."
from "NASA Space Technology Roadmaps and Priorities:" 2012, page 203
 
This was for the ISS, their goal was 90%
How many racks?
will this technology be used on the DC?,
has this technology matured?

Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: obi-wan on 07/10/2014 11:21 pm
According to Wayne Hale's twitter account, SNC is presenting their development plans for Dream Chaser today to the grey-haired eminences of the NASA Alumni League. It would be really interesting to see what they presented (although Wayne called it a fairly standard management pitch), and anything that comes out of the discussion. Wayne says there was some pushback about not planning to do a pad abort test, for instance.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: mheney on 07/10/2014 11:57 pm
I don't recall a pad abort test for Shuttle ....
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: baldusi on 07/11/2014 12:22 am

I don't recall a pad abort test for Shuttle ....
But they had insight so it was OK, right?
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: wannamoonbase on 07/11/2014 10:58 am

I don't recall a pad abort test for Shuttle ....
But they had insight so it was OK, right?

I think it says alot about the shuttle for other reasons.  Some of the grey hairs probably thought a pad abort wasn't needed after the experience of Mercury, Gemini, Apollo and it not being needed. 

More likely there are grey hairs that kept quiet or were forced to stay quiet during shuttle development and they don't want the mistake repeated.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: edkyle99 on 07/11/2014 03:53 pm

I don't recall a pad abort test for Shuttle ....
But they had insight so it was OK, right?

I think it says alot about the shuttle for other reasons.  Some of the grey hairs probably thought a pad abort wasn't needed after the experience of Mercury, Gemini, Apollo and it not being needed. 

More likely there are grey hairs that kept quiet or were forced to stay quiet during shuttle development and they don't want the mistake repeated.
According to this article, NASA did consider, early on, the idea of flying STS-1 as an intentional RTLS test flight.
http://www.tested.com/science/space/460233-space-shuttles-controversial-launch-abort-plan/

The problem was that it would had to have been manned, which kind of defeated the whole point of such a test.

 - Ed Kyle
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: arachnitect on 07/11/2014 04:12 pm
AIUI Dreamchaser can pad abort, correct? They just don't have a test planned.

If I'm wrong, when does the abort window open?

SNC wants brownie points in CCtCap for aborting to dry land.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: adrianwyard on 07/11/2014 04:18 pm
IIRC they plan powered atmospheric flights after drops from helicopter. These tests will have some features in common with lower-altitude aborts.

But it is interesting they aren't planning a pad abort test. There is still uncertainty on how much oomph those hybrids yield. If they are suited more to orbital maneuvering, perhaps launching from zero/zero is more worrying with DC than its competitors?
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Lars_J on 07/11/2014 04:45 pm
Yes, with only two hybrid abort motors, *and* having them spaced so far apart, you would think that a pad abort test would be a good thing. Can it abort safely, and get to the landing runway?

And if it can't get to the runway, how does DC plan on handling a ditch in the ocean? (there must be parts of the ascent trajectory where an abort would place them in the Atlantic)

I guess they are really placing bets on a significant "shuttle nostalgia" factor at NASA.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: adrianwyard on 07/11/2014 04:49 pm
A way back I (jokingly? seriously?) suggested the nose skid would make for a nice water ski if it did have to ditch.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: yg1968 on 07/11/2014 04:53 pm
Yes, with only two hybrid abort motors, *and* having them spaced so far apart, you would think that a pad abort test would be a good thing. Can it abort safely, and get to the landing runway?

And if it can't get to the runway, how does DC plan on handling a ditch in the ocean? (there must be parts of the ascent trajectory where an abort would place them in the Atlantic)

I guess they are really placing bets on a significant "shuttle nostalgia" factor at NASA.

I asked about that on the Spaceshow and Sirangelo answered me that in an emergency DC could land on water.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: rayleighscatter on 07/11/2014 05:25 pm
But it is interesting they aren't planning a pad abort test.
Pad Aborts is one of those things an additional 200 million buy. Half funding has its limitations.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: adrianwyard on 07/11/2014 09:19 pm
But it is interesting they aren't planning a pad abort test.
Pad Aborts is one of those things an additional 200 million buy. Half funding has its limitations.
A very fair point. I hope this was mentioned at the meeting.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: TrevorMonty on 07/11/2014 09:26 pm
Yes, with only two hybrid abort motors, *and* having them spaced so far apart, you would think that a pad abort test would be a good thing. Can it abort safely, and get to the landing runway?

And if it can't get to the runway, how does DC plan on handling a ditch in the ocean? (there must be parts of the ascent trajectory where an abort would place them in the Atlantic)

I guess they are really placing bets on a significant "shuttle nostalgia" factor at NASA.

I asked about that on the Spaceshow and Sierangelo answered me that in an emergency DC could land on water.

Sirangelo stated there were no black spots in DC launch/flight. Which I interpret as the DC being able to make a runway landing from where ever it aborts in the flight.

All the abort tests happen close to pad but an abort can happen anytime between launch and reaching orbit. What happens when abort is 100-1000kms downrange ie 2nd stage part of flight.?
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: arachnitect on 07/12/2014 01:48 pm

Sirangelo stated there were no black spots in DC launch/flight. Which I interpret as the DC being able to make a runway landing from where ever it aborts in the flight.

All the abort tests happen close to pad but an abort can happen anytime between launch and reaching orbit. What happens when abort is 100-1000kms downrange ie 2nd stage part of flight.?

Probably similar to shuttle, with transatlantic abort and abort to orbit.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Zed_Noir on 07/12/2014 02:40 pm

Sirangelo stated there were no black spots in DC launch/flight. Which I interpret as the DC being able to make a runway landing from where ever it aborts in the flight.

All the abort tests happen close to pad but an abort can happen anytime between launch and reaching orbit. What happens when abort is 100-1000kms downrange ie 2nd stage part of flight.?

Probably similar to shuttle, with transatlantic abort and abort to orbit.
The USAF might have to deploy a specialist manned spaceflight search & rescue unit with several detachments covering the flight path for ditching events. Or the USN could deploy floating assets for the same task . Also could be a commercial search & rescue capability. Would think this capability will be required for all US manned spaceflights.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Confusador on 07/16/2014 11:25 pm
This posted today by @TheLurioReport (https://twitter.com/TheLurioReport/status/489540963912916992)
Quote
Understand that Sierra Nevada will be changing the Dream Chaser main propulsion from hybrid to innovative liquid. See coming issue of Report

I'm going to file that under 'rumor' and not 'update', but it's an interesting thought.  "Innovative liquid" sounds like Xcor to me, especially since I can't imagine they're proposing developing a new engine at this stage.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: sublimemarsupial on 07/16/2014 11:29 pm
This posted today by @TheLurioReport (https://twitter.com/TheLurioReport/status/489540963912916992)
Quote
Understand that Sierra Nevada will be changing the Dream Chaser main propulsion from hybrid to innovative liquid. See coming issue of Report

I'm going to file that under 'rumor' and not 'update', but it's an interesting thought.  "Innovative liquid" sounds like Xcor to me, especially since I can't imagine they're proposing developing a new engine at this stage.

Isn't it more likely to be ORBITEC's vortex engines, rather than anything from Xcor, seeing as how SNC just bought ORBITEC?

http://www.orbitec.com/propulsion.html
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Pipcard on 07/18/2014 09:51 pm

Sirangelo stated there were no black spots in DC launch/flight. Which I interpret as the DC being able to make a runway landing from where ever it aborts in the flight.

All the abort tests happen close to pad but an abort can happen anytime between launch and reaching orbit. What happens when abort is 100-1000kms downrange ie 2nd stage part of flight.?

Probably similar to shuttle, with transatlantic abort and abort to orbit.
The USAF might have to deploy a specialist manned spaceflight search & rescue unit with several detachments covering the flight path for ditching events. Or the USN could deploy floating assets for the same task . Also could be a commercial search & rescue capability. Would think this capability will be required for all US manned spaceflights.
And this is exactly why spacecraft that land on a runway don't have a advantage in terms of not needing a recovery fleet.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: jtrame on 07/18/2014 10:22 pm

Sirangelo stated there were no black spots in DC launch/flight. Which I interpret as the DC being able to make a runway landing from where ever it aborts in the flight.

All the abort tests happen close to pad but an abort can happen anytime between launch and reaching orbit. What happens when abort is 100-1000kms downrange ie 2nd stage part of flight.?

Probably similar to shuttle, with transatlantic abort and abort to orbit.
The USAF might have to deploy a specialist manned spaceflight search & rescue unit with several detachments covering the flight path for ditching events. Or the USN could deploy floating assets for the same task . Also could be a commercial search & rescue capability. Would think this capability will be required for all US manned spaceflights.
And this is exactly why spacecraft that land on a runway don't have a advantage in terms of not needing a recovery fleet.

Exactly right.  Any one of the three could potentially need to land in the ocean if an abort happens within certain windows. 

If we are going to base our LEO efforts on one or two commercial providers, do the providers spring for the rescue assets, or do we (ie. government, NASA, taxpayers, etc.) fund the contingency?

The advantages of landing on a runway for all intents and purposes come later, at the conclusion of a successful mission.  And certainly an argument exists that says as promised, all three competitors offer similar or equal advantages then too.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: arachnitect on 07/18/2014 10:47 pm
If we are going to base our LEO efforts on one or two commercial providers, do the providers spring for the rescue assets, or do we (ie. government, NASA, taxpayers, etc.) fund the contingency?

CCtCAP Q/A (NASA responses in blue):
Quote
12. [TA01] Can you clarify the difference between recovery operations & SAR services with respect to Contractor requirements?
According CCT-PLN-1100, recovery is defined as “The process of proceeding to a designated nominal landing site, and retrieving crew, flight crew equipment, cargo, and payloads after a planned nominal landing” The Contractor is required to provide end to end transportation service including crew recovery for nominal landings.
Search and Rescue (SAR) is defined as “the process of locating the crew, proceeding to their position, and providing assistance.” NASA retains the responsibility to ensure a SAR capability exists for ascent and reentry phases of flight. The Contractor is responsible for interfacing with the SAR service in order to ensure survival of the crew (interface between CTS system and SAR forces).

77. [L.20-1 TA01] The traditional search and rescue services provided by NASA for off nominal or abort water landings may not be required for some CTS offerings, so how will this cost be assessed for vehicles that require this service and how will that cost be evaluated in the price factor of individual offerings?
Search and Rescue (SAR) services will be provided by the Government. SAR services are not a contractual requirement and thus, are not allocated to the Contractor. Therefore, SAR services will not be assessed as part of the price evaluation.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Lar on 07/19/2014 12:18 am
77. [L.20-1 TA01] The traditional search and rescue services provided by NASA for off nominal or abort water landings may not be required for some CTS offerings, so how will this cost be assessed for vehicles that require this service and how will that cost be evaluated in the price factor of individual offerings?
Search and Rescue (SAR) services will be provided by the Government. SAR services are not a contractual requirement and thus, are not allocated to the Contractor. Therefore, SAR services will not be assessed as part of the price evaluation.

That strikes me as odd.. SAR should be included in the TCO calculations. If one provider has a scheme that will never require SAR or will require cheaper SAR (no propellant safing perhaps?) that should be factored in.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Nomadd on 07/19/2014 12:56 am

And this is exactly why spacecraft that land on a runway don't have a advantage in terms of not needing a recovery fleet.

 A recovery fleet probably isn't going to have much to do with SAR. Capsules are generally recovered in the Pacific while an abort SAR will probably be in the Atlantic.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Zed_Noir on 07/19/2014 10:24 am
77. [L.20-1 TA01] The traditional search and rescue services provided by NASA for off nominal or abort water landings may not be required for some CTS offerings, so how will this cost be assessed for vehicles that require this service and how will that cost be evaluated in the price factor of individual offerings?
Search and Rescue (SAR) services will be provided by the Government. SAR services are not a contractual requirement and thus, are not allocated to the Contractor. Therefore, SAR services will not be assessed as part of the price evaluation.

That strikes me as odd.. SAR should be included in the TCO calculations. If one provider has a scheme that will never require SAR or will require cheaper SAR (no propellant safing perhaps?) that should be factored in.

IMO the reasonings behind government provided SAR capability are assembling and  maintaining the new SAR asserts is just duplicating existing USAF/USN/USCG asserts and the possible legal liability issues with non-governmental SAR.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: guckyfan on 07/19/2014 10:34 am
77. [L.20-1 TA01] The traditional search and rescue services provided by NASA for off nominal or abort water landings may not be required for some CTS offerings, so how will this cost be assessed for vehicles that require this service and how will that cost be evaluated in the price factor of individual offerings?
Search and Rescue (SAR) services will be provided by the Government. SAR services are not a contractual requirement and thus, are not allocated to the Contractor. Therefore, SAR services will not be assessed as part of the price evaluation.

That strikes me as odd.. SAR should be included in the TCO calculations. If one provider has a scheme that will never require SAR or will require cheaper SAR (no propellant safing perhaps?) that should be factored in.

IMO the reasonings behind government provided SAR capability are assembling and  maintaining the new SAR asserts is just duplicating existing USAF/USN/USCG asserts and the possible legal liability issues with non-governmental SAR.

Sure but the cost should be figured in when launch cost are compared. I think it is similar with providing berthing or docking adapters to the launch company. They are given without payment but are factored in for launch cost.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: rayleighscatter on 07/19/2014 01:24 pm
There's no real savings, government SAR will mobilize in a crisis regardless, especially when it involves government employees on official business.

If a plane crashes in the ocean the federal government won't wait to see how well Delta can rescue everyone on their own either.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: yg1968 on 07/19/2014 01:36 pm
This posted today by @TheLurioReport (https://twitter.com/TheLurioReport/status/489540963912916992)
Quote
Understand that Sierra Nevada will be changing the Dream Chaser main propulsion from hybrid to innovative liquid. See coming issue of Report

I'm going to file that under 'rumor' and not 'update', but it's an interesting thought.  "Innovative liquid" sounds like Xcor to me, especially since I can't imagine they're proposing developing a new engine at this stage.

Isn't it more likely to be ORBITEC's vortex engines, rather than anything from Xcor, seeing as how SNC just bought ORBITEC?

http://www.orbitec.com/propulsion.html

Isn't it a bit late to be changing engines on DC?
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: vt_hokie on 07/19/2014 02:07 pm
That's my question as well, and if they do change, does this apply to the orbital test vehicle already under construction?
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: A_M_Swallow on 07/19/2014 04:30 pm
77. [L.20-1 TA01] The traditional search and rescue services provided by NASA for off nominal or abort water landings may not be required for some CTS offerings, so how will this cost be assessed for vehicles that require this service and how will that cost be evaluated in the price factor of individual offerings?
Search and Rescue (SAR) services will be provided by the Government. SAR services are not a contractual requirement and thus, are not allocated to the Contractor. Therefore, SAR services will not be assessed as part of the price evaluation.

That strikes me as odd.. SAR should be included in the TCO calculations. If one provider has a scheme that will never require SAR or will require cheaper SAR (no propellant safing perhaps?) that should be factored in.

IMO the reasonings behind government provided SAR capability are assembling and  maintaining the new SAR asserts is just duplicating existing USAF/USN/USCG asserts and the possible legal liability issues with non-governmental SAR.

The CCtCap bidders are also planning none government commercial flights.  These are likely to need SAR as well.  Will the US Government be charging for this service?  Does it charge civilian aircraft and ships for a similar service?
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Zed_Noir on 07/19/2014 05:37 pm
77. [L.20-1 TA01] The traditional search and rescue services provided by NASA for off nominal or abort water landings may not be required for some CTS offerings, so how will this cost be assessed for vehicles that require this service and how will that cost be evaluated in the price factor of individual offerings?
Search and Rescue (SAR) services will be provided by the Government. SAR services are not a contractual requirement and thus, are not allocated to the Contractor. Therefore, SAR services will not be assessed as part of the price evaluation.

That strikes me as odd.. SAR should be included in the TCO calculations. If one provider has a scheme that will never require SAR or will require cheaper SAR (no propellant safing perhaps?) that should be factored in.

IMO the reasonings behind government provided SAR capability are assembling and  maintaining the new SAR asserts is just duplicating existing USAF/USN/USCG asserts and the possible legal liability issues with non-governmental SAR.

Sure but the cost should be figured in when launch cost are compared. I think it is similar with providing berthing or docking adapters to the launch company. They are given without payment but are factored in for launch cost.
There's no real savings, government SAR will mobilize in a crisis regardless, especially when it involves government employees on official business.

If a plane crashes in the ocean the federal government won't wait to see how well Delta can rescue everyone on their own either.

@guckyfan you do realize the USAF/USN/USCG asserts are already pay for regardless if they are use for SAR ops or not. Personnel salaries, asserts maintenance cost and asserts fuel usage cost will be spend in any case.



Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Zed_Noir on 07/19/2014 05:37 pm
77. [L.20-1 TA01] The traditional search and rescue services provided by NASA for off nominal or abort water landings may not be required for some CTS offerings, so how will this cost be assessed for vehicles that require this service and how will that cost be evaluated in the price factor of individual offerings?
Search and Rescue (SAR) services will be provided by the Government. SAR services are not a contractual requirement and thus, are not allocated to the Contractor. Therefore, SAR services will not be assessed as part of the price evaluation.

That strikes me as odd.. SAR should be included in the TCO calculations. If one provider has a scheme that will never require SAR or will require cheaper SAR (no propellant safing perhaps?) that should be factored in.

IMO the reasonings behind government provided SAR capability are assembling and  maintaining the new SAR asserts is just duplicating existing USAF/USN/USCG asserts and the possible legal liability issues with non-governmental SAR.

The CCtCap bidders are also planning none government commercial flights.  These are likely to need SAR as well.  Will the US Government be charging for this service?  Does it charge civilian aircraft and ships for a similar service?

AFAIK maritime SAR cost are not charge to ones getting rescue. IRRC International maritime laws required nations to maintain and offer SAR capability to anyone in distress.

Even the operation of a small twin turbo-prop coastal SAR aircraft will in the tens of thousand dollars per operation hour. After you factor in crew salaries, crew training, aircraft maintenance, fuel cost and shore-based support.

Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Robotbeat on 07/19/2014 10:12 pm
This posted today by @TheLurioReport (https://twitter.com/TheLurioReport/status/489540963912916992)
Quote
Understand that Sierra Nevada will be changing the Dream Chaser main propulsion from hybrid to innovative liquid. See coming issue of Report

I'm going to file that under 'rumor' and not 'update', but it's an interesting thought.  "Innovative liquid" sounds like Xcor to me, especially since I can't imagine they're proposing developing a new engine at this stage.

Isn't it more likely to be ORBITEC's vortex engines, rather than anything from Xcor, seeing as how SNC just bought ORBITEC?

http://www.orbitec.com/propulsion.html

Isn't it a bit late to be changing engines on DC?
Better late than never! Hybrid propulsion is the biggest problem with DC. Fix that, and it could really give the Dragon V2 a run for its money. A shame DC wasn't liquid from the start. This is very good news to me.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: rpapo on 07/19/2014 11:57 pm
Actually, there was a lesson learned about fifteen years ago on this: it is quite sufficient for a project to advance one technology at a time.  When you try to do several new things at once, you can get bogged down on several fronts.  The example I am thinking of is the X-33: a worthy project, but perhaps overly ambitious for its time.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: yg1968 on 07/20/2014 01:55 am
This posted today by @TheLurioReport (https://twitter.com/TheLurioReport/status/489540963912916992)
Quote
Understand that Sierra Nevada will be changing the Dream Chaser main propulsion from hybrid to innovative liquid. See coming issue of Report

I'm going to file that under 'rumor' and not 'update', but it's an interesting thought.  "Innovative liquid" sounds like Xcor to me, especially since I can't imagine they're proposing developing a new engine at this stage.

Isn't it more likely to be ORBITEC's vortex engines, rather than anything from Xcor, seeing as how SNC just bought ORBITEC?

http://www.orbitec.com/propulsion.html

Isn't it a bit late to be changing engines on DC?
Better late than never! Hybrid propulsion is the biggest problem with DC. Fix that, and it could really give the Dragon V2 a run for its money. A shame DC wasn't liquid from the start. This is very good news to me.

Would Orbitec's engine need to be scaled up? Can that be done in 3 years?
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Prober on 07/20/2014 11:40 pm
This posted today by @TheLurioReport (https://twitter.com/TheLurioReport/status/489540963912916992)
Quote
Understand that Sierra Nevada will be changing the Dream Chaser main propulsion from hybrid to innovative liquid. See coming issue of Report

I'm going to file that under 'rumor' and not 'update', but it's an interesting thought.  "Innovative liquid" sounds like Xcor to me, especially since I can't imagine they're proposing developing a new engine at this stage.

Isn't it more likely to be ORBITEC's vortex engines, rather than anything from Xcor, seeing as how SNC just bought ORBITEC?

http://www.orbitec.com/propulsion.html

Isn't it a bit late to be changing engines on DC?
Better late than never! Hybrid propulsion is the biggest problem with DC. Fix that, and it could really give the Dragon V2 a run for its money. A shame DC wasn't liquid from the start. This is very good news to me.

Would Orbitec's engine need to be scaled up? Can that be done in 3 years?

yes
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: yg1968 on 07/21/2014 02:02 pm
Yes to both questions?
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Zed_Noir on 07/21/2014 10:09 pm
There is always the fallback position of begging buying some Super Dracos from SpaceX if the ORBITEC engine don't materialize in time.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Prober on 07/22/2014 02:30 am
There is always the fallback position of begging buying some Super Dracos from SpaceX if the ORBITEC engine don't materialize in time.

why?  Orbitec should be able to have parts in very short order, its a modern design.

Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Robotbeat on 07/22/2014 03:47 am
There is always the fallback position of begging buying some Super Dracos from SpaceX if the ORBITEC engine don't materialize in time.
You're joking, right? People act as if the only rocket company in the world is SpaceX.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: jongoff on 07/22/2014 04:27 am
There is always the fallback position of begging buying some Super Dracos from SpaceX if the ORBITEC engine don't materialize in time.
You're joking, right? People act as if the only rocket company in the world is SpaceX.

No joke. Also, SNC has stated over and over again that they'd like a non-toxic propellant for OMS/RCS applications, not NTO/MMH. Super Dracos are sweet engines, but I'm a big fan of seeing other avenues investigated as well. Can't say I've ever been that amazed by the Vortex engine technology, but if it allows them to switch to liquid propulsion it's definitely better than the status quo.

~Jon
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Zed_Noir on 07/22/2014 05:02 am
Would Orbitec's engine need to be scaled up? Can that be done in 3 years?
yes
There is always the fallback position of begging buying some Super Dracos from SpaceX if the ORBITEC engine don't materialize in time.

why?  Orbitec should be able to have parts in very short order, its a modern design.
... if the ORBITEC engine don't materialize in time...



Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Zed_Noir on 07/22/2014 05:03 am
There is always the fallback position of begging buying some Super Dracos from SpaceX if the ORBITEC engine don't materialize in time.
You're joking, right? People act as if the only rocket company in the world is SpaceX.

No joke. Also, SNC has stated over and over again that they'd like a non-toxic propellant for OMS/RCS applications, not NTO/MMH. Super Dracos are sweet engines, but I'm a big fan of seeing other avenues investigated as well. Can't say I've ever been that amazed by the Vortex engine technology, but if it allows them to switch to liquid propulsion it's definitely better than the status quo.

~Jon

Not joking except the begging part. Super Dracos will be available and in mass production in three years time. So if the scale-up ORBITEC don't come online, what other liquid engines will be available to replace the hybrid engines?

As I pointed out in my post. This fallback is only necessary if the OBITEC engine don't come online.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Robotbeat on 07/22/2014 05:35 am
Bantam engines, for one. Countless others. Ask XCOR, they could hook you up with a non-toxic pump-fed liquid engine that will never wear out.

Also, SuperDracos are 3d printed, so no such thing as mass-production. ;)

Don't get SpaceX-myopia.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: A_M_Swallow on 07/22/2014 08:53 am

Not joking except the begging part. Super Dracos will be available and in mass production in three years time. So if the scale-up ORBITEC don't come online, what other liquid engines will be available to replace the hybrid engines?

As I pointed out in my post. This fallback is only necessary if the OBITEC engine don't come online.

Talk to NASA about the HD5.  5000lbf from methane/LOX.  Optional RCS that is also methane/LOX.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Zed_Noir on 07/22/2014 04:28 pm
...
Also, SuperDracos are 3d printed, so no such thing as mass-production. ;)
...
Just need more 3D printers.  ::) Imagine a row of 3D printers running the same print instructions outputting batches of parts.

Getting OT. Will not post further on this.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Zed_Noir on 07/22/2014 04:29 pm
The RB-88 Bantam LOX/Ethanol engine, the Xcor XR-5K18 LOX/RP1 engine and the HD5 LOX/Methane Morpheus engine all required cryogenic tankage for LOX. Which I guess would required some revision to the Dreamchaser design to reduce boil-off.

A hypergolic engine is easier replacement for the current hybrid engine.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Rocket Science on 07/22/2014 04:36 pm
The RB-88 Bantam LOX/Ethanol engine, the Xcor XR-5K18 LOX/RP1 engine and the HD5 LOX/Methane Morpheus engine all required cryogenic tankage for LOX. Which I guess would required some revision to the Dreamchaser design to reduce boil-off.

A hypergolic engine is easier replacement for the current hybrid engine.
I agree it would, but it would go against SNC wanting DC "runway safe" right after wheels stop...
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Zed_Noir on 07/22/2014 04:41 pm
The RB-88 Bantam LOX/Ethanol engine, the Xcor XR-5K18 LOX/RP1 engine and the HD5 LOX/Methane Morpheus engine all required cryogenic tankage for LOX. Which I guess would required some revision to the Dreamchaser design to reduce boil-off.

A hypergolic engine is easier replacement for the current hybrid engine.
I agree it would, but it would go against SNC wanting DC "runway safe" right after wheels stop...

What SNC wants and what they can get funding for will be interesting.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Rocket Science on 07/22/2014 04:43 pm
The RB-88 Bantam LOX/Ethanol engine, the Xcor XR-5K18 LOX/RP1 engine and the HD5 LOX/Methane Morpheus engine all required cryogenic tankage for LOX. Which I guess would required some revision to the Dreamchaser design to reduce boil-off.

A hypergolic engine is easier replacement for the current hybrid engine.
I agree it would, but it would go against SNC wanting DC "runway safe" right after wheels stop...

What SNC wants and what they can get funding for will be interesting.
No bucks... no Buck Rogers... ;D
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: IslandPlaya on 07/22/2014 04:50 pm
No Flash.
No Flash Gordon.
 ;D
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: TrevorMonty on 07/22/2014 05:06 pm
Is there a known issue with the Hybrid engines in DC?. If so can someone please supply a link to source of this information.

Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: yg1968 on 07/22/2014 06:15 pm
Is there a known issue with the Hybrid engines in DC?. If so can someone please supply a link to source of this information.

The video of one of the first SS2 engine test showed some instability. The rest of the information comes from posts from Parabolic Arc on the SS2 thread. SNC also makes SS2's hybrid engines. 
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: yg1968 on 07/22/2014 06:23 pm
There is always the fallback position of begging buying some Super Dracos from SpaceX if the ORBITEC engine don't materialize in time.
You're joking, right? People act as if the only rocket company in the world is SpaceX.

No joke. Also, SNC has stated over and over again that they'd like a non-toxic propellant for OMS/RCS applications, not NTO/MMH. Super Dracos are sweet engines, but I'm a big fan of seeing other avenues investigated as well. Can't say I've ever been that amazed by the Vortex engine technology, but if it allows them to switch to liquid propulsion it's definitely better than the status quo.

~Jon

Out of curiosity, why do you not like the Vortex engine technology?
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Silmfeanor on 07/22/2014 06:53 pm
Can't say I've ever been that amazed by the Vortex engine technology
Out of curiosity, why do you not like the Vortex engine technology?
not like =! I am not that amazed.
So I don't think Jon doesn't like it, but he just doesn't think it is all that special compared to other engines.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: TrevorMonty on 07/22/2014 06:57 pm
Is there a known issue with the Hybrid engines in DC?. If so can someone please supply a link to source of this information.

The video of one of the first SS2 engine test showed some instability. The rest of the information comes from posts from Parabolic Arc on the SS2 thread. SNC also makes SS2's hybrid engines.
The SS2 is not the DC. The question is still unanswered.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: TrevorMonty on 07/22/2014 07:08 pm
No mention of engine problems in this recent article.

http://www.parabolicarc.com/2014/07/08/sierra-nevada-completes-dream-chaser-propulsion-reaction-control-milestone/


Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: jgoldader on 07/23/2014 11:48 am
Loved the phot of Archimbault in a pressure suit in the latest front page article.  Is there any info on the pressure suits SNC is considering?  Helmet looked a lot like G4C helmet but it was hard to tell.  Is this suit in that family?
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: yg1968 on 07/23/2014 12:21 pm
Is there a known issue with the Hybrid engines in DC?. If so can someone please supply a link to source of this information.

The video of one of the first SS2 engine test showed some instability. The rest of the information comes from posts from Parabolic Arc on the SS2 thread. SNC also makes SS2's hybrid engines.
The SS2 is not the DC. The question is still unanswered.

Yes, I know. But there a lot of similarities between these two hybrid engines. Other than that I don't think that we've heard anything official.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: JasonAW3 on 07/23/2014 02:35 pm
Loved the phot of Archimbault in a pressure suit in the latest front page article.  Is there any info on the pressure suits SNC is considering?  Helmet looked a lot like G4C helmet but it was hard to tell.  Is this suit in that family?

I'm really not certain that that's an ACTUAL pressure suit.  Seems to fit kind of loosely to be an actual pressure suit.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: JasonAW3 on 07/23/2014 03:01 pm
Ok, let's assume for the moment that they can't use the Hybrid motors and they have to develope a whole new engine.

     What relatively safe fuel and oxidized combinations, (nontoxic) that are noncryogenic, and would give sufficent performance, are available?

     I realise that much of this speculation would depend on the motor design, but let's look at the fuel and oxidizers as a starting point.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Rocket Science on 07/23/2014 03:10 pm
Ok, let's assume for the moment that they can't use the Hybrid motors and they have to develope a whole new engine.

     What relatively safe fuel and oxidized combinations, (nontoxic) that are noncryogenic, and would give sufficent performance, are available?

     I realise that much of this speculation would depend on the motor design, but let's look at the fuel and oxidizers as a starting point.
LOX-Alcohol Rocket Engine, but not really good for pad abort...
You could add Nitrous oxide-Alcohol, still not good for abort. Noncryo is a whole other issue...
Then they can go back to the SRM on the adapter as was seen for the HL-20.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: jtrame on 07/23/2014 03:24 pm
Loved the phot of Archimbault in a pressure suit in the latest front page article.  Is there any info on the pressure suits SNC is considering?  Helmet looked a lot like G4C helmet but it was hard to tell.  Is this suit in that family?

I'm really not certain that that's an ACTUAL pressure suit.  Seems to fit kind of loosely to be an actual pressure suit.
It there an inside view of the mock-up on the monitor behind him?  Sure would be neat to see the inside, sorta like we saw the Dragon V2.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Zed_Noir on 07/23/2014 06:57 pm
...
LOX-Alcohol Rocket Engine, but not really good for pad abort
...
Then why is Boeing using the RB-88 LOX/Ethanol  Bantam engine for the CST-100 abort escape system?
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: arachnitect on 07/23/2014 07:29 pm
...
LOX-Alcohol Rocket Engine, but not really good for pad abort
...
Then why is Boeing using the RB-88 LOX/Ethanol  Bantam engine for the CST-100 abort escape system?


They're using a modified version running NTO/MMH
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: bubbagret on 07/23/2014 07:30 pm
Ok, let's assume for the moment that they can't use the Hybrid motors and they have to develope a whole new engine.

     What relatively safe fuel and oxidized combinations, (nontoxic) that are noncryogenic, and would give sufficent performance, are available?

     I realise that much of this speculation would depend on the motor design, but let's look at the fuel and oxidizers as a starting point.

H2O2/Kerosene, which is 1 of the fuel combos that ORBITEC is working with. Simple, hypergolic, high energy, and "green".
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Rocket Science on 07/23/2014 07:44 pm
Ok, let's assume for the moment that they can't use the Hybrid motors and they have to develope a whole new engine.

     What relatively safe fuel and oxidized combinations, (nontoxic) that are noncryogenic, and would give sufficent performance, are available?

     I realise that much of this speculation would depend on the motor design, but let's look at the fuel and oxidizers as a starting point.

H2O2/Kerosene, which is 1 of the fuel combos that ORBITEC is working with. Simple, hypergolic, high energy, and "green".
One needs caution when around H2O2, special handling and garments...
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: bubbagret on 07/23/2014 07:48 pm
Ok, let's assume for the moment that they can't use the Hybrid motors and they have to develope a whole new engine.

     What relatively safe fuel and oxidized combinations, (nontoxic) that are noncryogenic, and would give sufficent performance, are available?

     I realise that much of this speculation would depend on the motor design, but let's look at the fuel and oxidizers as a starting point.

H2O2/Kerosene, which is 1 of the fuel combos that ORBITEC is working with. Simple, hypergolic, high energy, and "green".
One needs caution when around H2O2, special handling and garments...
Ok, let's assume for the moment that they can't use the Hybrid motors and they have to develope a whole new engine.

     What relatively safe fuel and oxidized combinations, (nontoxic) that are noncryogenic, and would give sufficent performance, are available?

     I realise that much of this speculation would depend on the motor design, but let's look at the fuel and oxidizers as a starting point.

H2O2/Kerosene, which is 1 of the fuel combos that ORBITEC is working with. Simple, hypergolic, high energy, and "green".
One needs caution when around H2O2, special handling and garments...
As they would with a lot of fuels.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: yg1968 on 07/23/2014 09:21 pm
Sierra Nevada Corporation Announces Cooperative Understanding with Japanese Aerospace Exploration Agency for the Dream Chaser® Space System

[...] Additionally, SNC and JAXA will explore the possibility of launching and landing the Dream Chaser spacecraft in Japan.

This sounds more interesting that the DLR/ESA agreement. It would be cool to see DC launch from Japan and the United States. This is exactly what commercial crew should be abound: finding new markets for commercial spacecrafts.  Japan has always wanted an independent human spaceflight program. It is still not clear if they will go ahead with their HTV-R.

There is two ways of seing SNC's recent agreements: they are building up their portfolio for CCtCap or they are preparing contingent plans in case, they get downselected. But either way, SNC seems commited to finishing DC. The acquisition of Orbitec is a case in point. It shows that they are resolved in seing DC through.  They have invested a lot of skin in the game in DC (which should have been a requirement for commercial crew).
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Coastal Ron on 07/23/2014 10:01 pm
SpaceX may have the most progress on their hardware for Commercial Crew, but Sierra Nevada is making the most deals with other space agencies:

SNC Enlists Japan for Dream Chaser Study
http://www.spacenews.com/article/civil-space/41358snc-enlists-japan-for-dream-chaser-study

From the article:

"Under the cooperative understanding, the two sides will collaborate on mission concepts and potential applications of Japanese technologies for Dream Chaser, SNC said in a press release. In addition, JAXA and SNC will explore the possibility of launching and landing the spacecraft in Japan, the release said."

Launching and landing spacecraft in Japan!  This was actually one of the things I hoped the Commercial Crew program would do unofficially, which is create a commercial system that other countries would use.  I hope it ultimately happens.

Great news, and GREAT JOB Sierra Nevada!!
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Rocket Science on 07/23/2014 10:58 pm
Ok, let's assume for the moment that they can't use the Hybrid motors and they have to develope a whole new engine.

     What relatively safe fuel and oxidized combinations, (nontoxic) that are noncryogenic, and would give sufficent performance, are available?

     I realise that much of this speculation would depend on the motor design, but let's look at the fuel and oxidizers as a starting point.

H2O2/Kerosene, which is 1 of the fuel combos that ORBITEC is working with. Simple, hypergolic, high energy, and "green".
One needs caution when around H2O2, special handling and garments...
Ok, let's assume for the moment that they can't use the Hybrid motors and they have to develope a whole new engine.

     What relatively safe fuel and oxidized combinations, (nontoxic) that are noncryogenic, and would give sufficent performance, are available?

     I realise that much of this speculation would depend on the motor design, but let's look at the fuel and oxidizers as a starting point.

H2O2/Kerosene, which is 1 of the fuel combos that ORBITEC is working with. Simple, hypergolic, high energy, and "green".
One needs caution when around H2O2, special handling and garments...
As they would with a lot of fuels.
I'm referring to your choice of oxidizer not the fuel...
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: vulture4 on 07/26/2014 05:06 pm
For ambient storage I would go with peroxide/RP-1 for an ISP of 250, well established reliable design: http://en.wikipedia.org/wiki/Bristol_Siddeley_Gamma
However I think cryos (LOX/RP-1) would also be practicalas the launch abort LOX tank can easily be kept cool be recirculation.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Lars_J on 07/27/2014 05:42 am
However I think cryos (LOX/RP-1) would also be practicalas the launch abort LOX tank can easily be kept cool be recirculation.

Easily? For the required 6+ month stay at ISS?
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: SWGlassPit on 07/28/2014 10:26 pm
RP-1 would not play nicely on orbit.  Freezing point too high, flash point too low.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Pipcard on 08/02/2014 07:13 pm
Does the lack of body flaps affect aerodynamics in any way?

edit: It does have body flaps, but they don't stick out. See the second image on here (http://arcturus415.wordpress.com/2013/08/03/sierra-nevada-corporation-chasing-a-dream-with-dream-chaser/)
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: FutureSpaceTourist on 08/18/2014 11:36 am
I'm catching up on the news about SNC switching to liquid engines for DC.

IIRC I believe SNC didn't score as highly as Boeing or SpaceX on the technical assessments in previous commercial crew award rounds. I'm wondering if the engine switch was, at least in part, an attempt to improve matters for CCtCAP?
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Todd Martin on 08/18/2014 03:15 pm
While there has been discussion on this thread regarding a switch to Liquid fueled engine for DreamChaser and the most recent CCt-Cap article on NSF makes a mention of it (with a broken link), I have not seen any confirmation of this change from SNC.

Changing a spacecraft from a hybrid fueled engine to a liquid fueled engine is a huge change.  Consider the fuel tank size and location, the plumbing, the weight changes & center of gravity, the thrust profile and software changes...  I find it hard to believe that any commercial crew entrant would do this AFTER spending years & millions of dollars proving to NASA that their spacecraft is safe & ready to be built AND right before the winners are announced.  If it is true, their chances of winning would be substantially reduced since their paperwork is based on a different propulsion system!

Call me a doubting Thomas, but show me something tangible that SNC is really doing this.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Lars_J on 08/18/2014 05:04 pm
Todd, from Chris' latest article: (saw this in the update thread, you may have seen this already)
http://www.nasaspaceflight.com/2014/08/cctcapnasa-wont-abandon-commercial-crew-loser/

Quote
“SNC has also baselined a new propulsion system design (a pure liquid system design rather than a hybrid) in conjunction with their purchase of ORBITEC.”

I'm not surprised (assuming this pans out)... If the engines were going to be restartable on orbit, and used in finer orbital adjustment, I don't see how they ever thought that a hybrid rocket engine could be made to work well without lots of testing. But what do I know, I'm certainly not an expert.

Expect VG to announce a switch in propulsion for SpaceShip 2 very shortly...
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: yg1968 on 08/18/2014 05:39 pm
While there has been discussion on this thread regarding a switch to Liquid fueled engine for DreamChaser and the most recent CCt-Cap article on NSF makes a mention of it (with a broken link), I have not seen any confirmation of this change from SNC.

Changing a spacecraft from a hybrid fueled engine to a liquid fueled engine is a huge change.  Consider the fuel tank size and location, the plumbing, the weight changes & center of gravity, the thrust profile and software changes...  I find it hard to believe that any commercial crew entrant would do this AFTER spending years & millions of dollars proving to NASA that their spacecraft is safe & ready to be built AND right before the winners are announced.  If it is true, their chances of winning would be substantially reduced since their paperwork is based on a different propulsion system!

Call me a doubting Thomas, but show me something tangible that SNC is really doing this.

Chris' quote comes from the ASAP meeting (see the last paragraph of page 5):
http://oiir.hq.nasa.gov/asap/documents/ASAP_Third_Quarterly_Meeting_2014.pdf

Furthermore Sirangelo also said that the RCS thrusters and the main engine use the same fuel. The RCS thrusters are provided by Orbitec.

http://forum.nasaspaceflight.com/index.php?topic=29416.msg1242864#msg1242864

See also:
Quote
Understand that Sierra Nevada will be changing the Dream Chaser main propulsion from hybrid to innovative liquid. See coming issue of Report
https://twitter.com/TheLurioReport/status/489540963912916992

Quote
Dream Chaser motor change said to improve reusability, performance & - STOP - news may precede TLR issue, but don't want teaser pushing it.
https://twitter.com/TheLurioReport/status/489608586666840065
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: rayleighscatter on 08/24/2014 03:40 pm
Would the Atlas V 412 have the energy to deliver DC to the station without the use of DC's own main engines? All I could find data for was the 411 and it seems to have the performance (albeit on a different inclination) to manage. I'm not sure if on the correct inclination, with it loaded with crew/supplies, and with that extra solid, if it could manage.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: sdsds on 08/24/2014 09:56 pm
As I'm reading it, Steve Lindsey in his capacity as Chief of the NASA Astronaut Corps arranged for himself to command the final Shuttle mission. Now as SNC's senior program manager for Dream Chaser Lindsey is likely to arrange for himself to command the first US non-Shuttle mission. (Assuming DC flies with a crew before Dragon.)

If it does play out that way it will confirm in my mind at least that the "gap" was not too long!
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Lars_J on 08/25/2014 12:55 am
From the update thread:

Mark Sirangelo stated following from America space interview.
 http://www.americaspace.com/?p=66192

 “We have not announced a change in propulsion systems and that was not a quote from us.”

“It was likely meant to refer to our acquisition of Orbitec as we now have an expanded base of propulsion solutions and are exploring their use for future Dream Chaser variants.”

“There is no schedule change related to engines.”

So the DC is staying with it's existing hybrid engines for the first orbital version at least.

Not exactly the strongest denial I have read. Reading between the lines, it sounds like it is a planned change in the near future, but they did not want it released at this time. But I could be wrong.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: vt_hokie on 08/25/2014 01:55 am
Yeah, reading between the lines, I wouldn't be betting on the long term future of hybrids at this time.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: sojourner on 08/28/2014 04:41 pm
Forgive me if this has been brought up. In a recent presentation SpaceX has confirmed that they will be providing a new Dragon V2 for each flight for NASA.  Something to do with the re-certification process being the reason.

Will SNC be going the same route with Dreamchaser?
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: abaddon on 08/28/2014 05:17 pm
That's a really interesting question.  My gut feeling is that DreamChaser is going to be a more expensive article to build than Dragon V2 (for a variety of reasons), and they are going to need to reuse it to be price competitive, but I don't have any data to back that up.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: yg1968 on 08/28/2014 06:21 pm
That's a really interesting question.  My gut feeling is that DreamChaser is going to be a more expensive article to build than Dragon V2 (for a variety of reasons), and they are going to need to reuse it to be price competitive, but I don't have any data to back that up.

I suspect that it is right. Building a new Dream Chaser for each flight seems overly expensive. Reisman made it seem that it was their decision not to certify Dragon V2 for reuse (because it would have been too complicated to certify it for reuse) but he didn't say that NASA was against the idea.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Rocket Science on 08/28/2014 06:34 pm
That's a really interesting question.  My gut feeling is that DreamChaser is going to be a more expensive article to build than Dragon V2 (for a variety of reasons), and they are going to need to reuse it to be price competitive, but I don't have any data to back that up.

I suspect that it is right. Building a new Dream Chaser for each flight seems overly expensive. Reisman made it seem that it was their decision not to certify Dragon V2 for reuse (because it would have been too complicated to certify it for reuse) but he didn't say that NASA was against the idea.
IIRC Mark Sirangelo said each airframe should be good for 30 flights...
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: yg1968 on 08/28/2014 08:02 pm
That's a really interesting question.  My gut feeling is that DreamChaser is going to be a more expensive article to build than Dragon V2 (for a variety of reasons), and they are going to need to reuse it to be price competitive, but I don't have any data to back that up.

I suspect that it is right. Building a new Dream Chaser for each flight seems overly expensive. Reisman made it seem that it was their decision not to certify Dragon V2 for reuse (because it would have been too complicated to certify it for reuse) but he didn't say that NASA was against the idea.
IIRC Mark Sirangelo said each airframe should be good for 30 flights...

Each Dragon V2 should be good for at least 10 flights. But SpaceX considered that certification of a reused capsule would have been overly complex.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: oiorionsbelt on 08/28/2014 10:22 pm
That's a really interesting question.  My gut feeling is that DreamChaser is going to be a more expensive article to build than Dragon V2 (for a variety of reasons), and they are going to need to reuse it to be price competitive, but I don't have any data to back that up.

I suspect that it is right. Building a new Dream Chaser for each flight seems overly expensive. Reisman made it seem that it was their decision not to certify Dragon V2 for reuse (because it would have been too complicated to certify it for reuse) but he didn't say that NASA was against the idea.
IIRC Mark Sirangelo said each airframe should be good for 30 flights...

Each Dragon V2 should be good for at least 10 flights. But SpaceX considered that certification of a reused capsule would have been overly complex.
Would a winged vehicle be any easier  to re certify than a capsule? If they are the same will that go against SNC chances of getting funding for CCt-CAP
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: TrevorMonty on 08/29/2014 04:08 am
Part4 of AmericaSpace.com Mark Sirangelo interview.

http://www.americaspace.com/?p=66395#more-66395
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: rcoppola on 08/29/2014 03:29 pm
The reuse question is very interesting, so I'm going over to the "Pros and Cons, Dragon V2, CST-100 and Dream Chaser" thread to discuss it.

http://forum.nasaspaceflight.com/index.php?topic=34873.225
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: TrevorMonty on 08/31/2014 09:24 pm
Part5 of AmericaSpace interview.

 http://www.americaspace.com/?p=66787#more-66787
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Darkseraph on 09/05/2014 12:46 am
Forgive me if this is an entirely dumb question, as I know less about aerodynamics than orbital mechanics....but will the more complex shape of the DC make its aborts more complicated than say a capsule? It's a winged lifting body, so in my mind that will force it to veer to the side as it aborts, rather than on a simple parabolic trajectory. I'm not sure about it. Totally correct me if that's not bs.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Rocket Science on 09/05/2014 01:17 am
Forgive me if this is an entirely dumb question, as I know less about aerodynamics than orbital mechanics....but will the more complex shape of the DC make its aborts more complicated than say a capsule? It's a winged lifting body, so in my mind that will force it to veer to the side as it aborts, rather than on a simple parabolic trajectory. I'm not sure about it. Totally correct me if that's not bs.
DC won’t generate much lift until it has gained a high enough velocity and AoA to the relative airflow. Remember a capsule has an offset cg and that has to be compensated for during an abort and is calculated in. DC will be able to abort and land on a runway such as the SLF at KSC or CCAFS. See my lifting body thread for a pad abort of the HL-20...

http://forum.nasaspaceflight.com/index.php?topic=29126.15
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: yg1968 on 09/05/2014 01:19 am
Part4 of AmericaSpace.com Mark Sirangelo interview.

http://www.americaspace.com/?p=66395#more-66395

This part of the article is interesting.

Quote
Therefore, if you were to launch on either the H2B or Ariane V, it would definitely be unmanned for cargo purposes?

“Yes.”

Could you eventually launch a manned Dream Chaser on either the H2B or Ariane V? Are you exploring that possibility to launch with people in the future?

“That’s not part of the discussions at this time.”
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: deltaV on 09/05/2014 01:47 am
Forgive me if this is an entirely dumb question, as I know less about aerodynamics than orbital mechanics....but will the more complex shape of the DC make its aborts more complicated than say a capsule? It's a winged lifting body, so in my mind that will force it to veer to the side as it aborts, rather than on a simple parabolic trajectory. I'm not sure about it. Totally correct me if that's not bs.

It's a lot easier to miss a runway than it is to miss the Atlantic Ocean. This will presumably make DC aborts more complicated than capsule aborts.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Rocket Science on 09/05/2014 02:08 am
Forgive me if this is an entirely dumb question, as I know less about aerodynamics than orbital mechanics....but will the more complex shape of the DC make its aborts more complicated than say a capsule? It's a winged lifting body, so in my mind that will force it to veer to the side as it aborts, rather than on a simple parabolic trajectory. I'm not sure about it. Totally correct me if that's not bs.

It's a lot easier to miss a runway than it is to miss the Atlantic Ocean. This will presumably make DC aborts more complicated than capsule aborts.
Why would I want to risk salt water intrusion into my expensive SC if I don’t have to? I’ve flown HL-20 pad aborts in a sim and it’s doable and you get you SC back in pristine shape... Well, let see how she actually performs during DC’s pad abort test and take it from there...
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Ronsmytheiii on 09/07/2014 04:57 pm
Part4 of AmericaSpace.com Mark Sirangelo interview.

http://www.americaspace.com/?p=66395#more-66395

This is interesting:

Quote
“Yes, the Ariane V could lift the Dream Chaser, not in a human capacity but in an unmanned capacity.”

Therefore, if you were to launch on either the H2B or Ariane V, it would definitely be unmanned for cargo purposes?

“Yes.”

That explains why ESA was looking to launch DC in a payload fairing. So you arent going to see ESA astronauts launch to ISS for Kourou, I guess the DC on Ariane V would be for microgravity flights, satellite servicing ect.  It still is a massive launcher for DC (which is meant to go uphill on the Atlas 412), I wonder if they will fly with another payload.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: jamesh9000 on 09/08/2014 08:59 pm
I may be reading way too much into this, but SNC has two "CCtCAP contingent" jobs that were advertised that are now "no longer available":

job1 (http://www.indeed.com/viewjob?jk=7ad12ffb6067e714&qd=dX16ILfYN-y4E5s1Y6Ztf2y1VqugYbEjYWIA3hRXMDV6NtGd3ri2jpfRdrcK6guATKnodTNs_L_o7_kUwAEXGBef7jniaSxDFHAguqR4g_4HA0vmCE-4iC2Qd13rm6Eh6gIUsyJs4IRptRqGe57AKQ&atk=191aor97j0nj24cg&utm_source=publisher&utm_medium=organic_listings&utm_campaign=affiliate)

job2 (http://www.indeed.com/viewjob?t=Guidance&c=Sierra+Nevada+Corporation&l=Louisville,+CO&jk=e6dd41022152c1db&utm_source=publisher&utm_medium=organic_listings&utm_campaign=affiliate#T27D)

Do you guys think this means they missed out? Or am I searching for leads where there are none?

Edit/Lar: Long URLs make readers sad because they mess up the scrolling/layout. Please shorten them, as I did here.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: king1999 on 09/08/2014 09:05 pm
Do you guys think this means they missed out? Or am I searching for leads where there are none?

Or simply they have the positions filled already?
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: yg1968 on 09/08/2014 09:17 pm
Do you guys think this means they missed out? Or am I searching for leads where there are none?

Or simply they have the positions filled already?

Either way, it does suggest that SNC knows the outcome of CCtCap which is interesting.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: jongoff on 09/08/2014 09:24 pm
Do you guys think this means they missed out? Or am I searching for leads where there are none?

Or simply they have the positions filled already?

Either way, it does suggest that SNC knows the outcome of CCtCap which is interesting.

Or it could just mean that they've found potential candidates they like for the two positions (in case they win CCtCap) and are no longer looking for new candidates.

~Jon
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: yg1968 on 09/08/2014 09:31 pm
Do you guys think this means they missed out? Or am I searching for leads where there are none?

Or simply they have the positions filled already?

Either way, it does suggest that SNC knows the outcome of CCtCap which is interesting.

Or it could just mean that they've found potential candidates they like for the two positions (in case they win CCtCap) and are no longer looking for new candidates.

~Jon

I would doubt it. You wouldn't remove a job posting unless you have a signed contract in hand.

I suspect that NASA is waiting for the CR to be passed by the House before announcing who the winners are. The House is expected to vote on the CR Thursday.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: docmordrid on 09/09/2014 02:50 am
I'd wait until they were at angels 30 on the way home.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: SoundForesight on 09/09/2014 06:35 am
I may be reading way too much into this, but SNC has two "CCtCAP contingent" jobs that were advertised that are now "no longer available"
...Do you guys think this means they missed out? Or am I searching for leads where there are none?

Following up with a search of Indeed jobs, I show 94 new SNC jobs referencing CCtCap (most say "Contingent - CCtCAP"). I don't see anything similar for SpaceX or Boeing.

Edit:  55 jobs, if 39 similar job postings removed.

http://www.indeed.com/jobs?as_and=snc&as_phr=%22cctcap%22&as_any=&as_not=&as_ttl=&as_cmp=&jt=all&st=&salary=&radius=25&fromage=7&limit=50&sort=date&psf=advsrch (http://www.indeed.com/jobs?as_and=snc&as_phr=%22cctcap%22&as_any=&as_not=&as_ttl=&as_cmp=&jt=all&st=&salary=&radius=25&fromage=7&limit=50&sort=date&psf=advsrch)
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: dglow on 09/09/2014 01:15 pm
Also: HR regulations can require an employer to publicly advertise open positions. Sometimes these requirements are met after-the-fact, with  the public post appearing after a position is filled.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: yg1968 on 09/09/2014 05:51 pm
I may be reading way too much into this, but SNC has two "CCtCAP contingent" jobs that were advertised that are now "no longer available"
...Do you guys think this means they missed out? Or am I searching for leads where there are none?

Following up with a search of Indeed jobs, I show 94 new SNC jobs referencing CCtCap (most say "Contingent - CCtCAP"). I don't see anything similar for SpaceX or Boeing.

Edit:  55 jobs, if 39 similar job postings removed.

http://www.indeed.com/jobs?as_and=snc&as_phr=%22cctcap%22&as_any=&as_not=&as_ttl=&as_cmp=&jt=all&st=&salary=&radius=25&fromage=7&limit=50&sort=date&psf=advsrch (http://www.indeed.com/jobs?as_and=snc&as_phr=%22cctcap%22&as_any=&as_not=&as_ttl=&as_cmp=&jt=all&st=&salary=&radius=25&fromage=7&limit=50&sort=date&psf=advsrch)

I suspect that Boeing and SpaceX wouldn't need that many new employees given that they are already receiving full funding under CCiCap whereas SNC is receiving half the funding.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: daj24 on 09/09/2014 06:04 pm
Also: HR regulations can require an employer to publicly advertise open positions. Sometimes these requirements are met after-the-fact, with  the public post appearing after a position is filled.

Often they specifically tailor the posting to fit the person who they have in mind for the job.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: yg1968 on 09/17/2014 06:18 am
What's next for DC. My guess is that they will keep their program active at least until April 28, 2015 when CRS2 is awarded. This should also allow them to finish their CCCtCap milestones.

In my opinion, they also need to find an investor for DC like Jeff Bezos or Paul Allen in order to complete at least one uncrewed demo flight.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Nibb31 on 09/17/2014 07:25 am
To compete for cargo, they would need to switch to CBM berthing because there is no point in returning cargo if you can't return an ISPR rack. Is DreamChaser's rear end tall enough to accomodate a CBM?
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: R7 on 09/17/2014 07:59 am
In my opinion, they also need to find an investor for DC like Jeff Bezos or Paul Allen in order to complete at least one uncrewed demo flight.

Or lifeline from milspace.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Lars-J on 09/17/2014 02:21 pm

To compete for cargo, they would need to switch to CBM berthing because there is no point in returning cargo if you can't return an ISPR rack. Is DreamChaser's rear end tall enough to accomodate a CBM?

Neither Dragon nor Cygnus can handle a ISPR rack at the moment, so it is not a requirement. (Dragon has a hatch that is big enough, but would require an internal redesign to hold it for the journey)
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Prober on 09/17/2014 02:26 pm
What's next for DC. My guess is that they will keep their program active at least until April 28, 2015 when CRS2 is awarded. This should also allow them to finish their CCCtCap milestones.

In my opinion, they also need to find an investor for DC like Jeff Bezos or Paul Allen in order to complete at least one uncrewed demo flight.

Maybe not an investor.   It's strange to me that SN didn't court another Nevada company, Bigelow.   Note if you will that Bigelow had some hands in both the SpaceX & Boeing design. 
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Rocket Science on 09/17/2014 02:31 pm
What's next for DC. My guess is that they will keep their program active at least until April 28, 2015 when CRS2 is awarded. This should also allow them to finish their CCCtCap milestones.

In my opinion, they also need to find an investor for DC like Jeff Bezos or Paul Allen in order to complete at least one uncrewed demo flight.

Maybe not an investor.   It's strange to me that SN didn't court another Nevada company, Bigelow.   Note if you will that Bigelow had some hands in both the SpaceX & Boeing design.
There was once talk of DC with Virgin for orbital flights... Who knows..?
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: abaddon on 09/17/2014 02:41 pm
Maybe not an investor.   It's strange to me that SN didn't court another Nevada company, Bigelow.   Note if you will that Bigelow had some hands in both the SpaceX & Boeing design.

I think there is some vast overrating of the importance of Bigelow in the CCtCAP selection process going on (not just this post I am replying to).  I can't imagine that having Bigelow on the team (when the "Dream Team" had so many other aerospace players) would have affected the end result one bit.

I also don't believe Bigelow had any hand in the DragonV2 design.  Do you have more specifics here?
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: SoundForesight on 09/17/2014 05:15 pm
I don't see this statement on either SNC's or SNC Space Systems' web site for press releases, but KRNV, a Reno, Nevada TV station reports the following as a statement issued by SNC:
http://www.mynews4.com/news/story/Sierra-Nevada-Corporation-misses-NASA-contract/LegXqlm0UUGPYgh2pcrH9A.cspx (http://www.mynews4.com/news/story/Sierra-Nevada-Corporation-misses-NASA-contract/LegXqlm0UUGPYgh2pcrH9A.cspx)

"Sierra Nevada Corporation (SNC) recognizes that NASA has made a selection of an alternative provider(s) in the Commercial Crew Transportation Capability Contract (CCtCap) competition. SNC is planning to have a debrief session with NASA soon to obtain the source selection statement and decision rationale. When this process is complete and after a thorough evaluation, SNC will elaborate further on its future options regarding the NASA Commercial Crew Transportation Capability (CCtCap) contract decision and the Dream Chaser program. Due to this pending activity SNC will have no further public statement at this time. We will be providing further information at a later date.

While SNC is disappointed NASA did not select its Dream Chaser® Space System for the CCtCap contract, SNC commends NASA for initiating the effort and is privileged to have been part of returning human space flight to the United States through our awarded contracts in all other phases of NASA’s Commercial Crew Program over the past four years."
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: plank on 09/17/2014 05:44 pm
What's next for DC. My guess is that they will keep their program active at least until April 28, 2015 when CRS2 is awarded. This should also allow them to finish their CCCtCap milestones.

In my opinion, they also need to find an investor for DC like Jeff Bezos or Paul Allen in order to complete at least one uncrewed demo flight.

Please excuse my ignorance but for what purpose will CRS2 be for?
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: arachnitect on 09/17/2014 05:50 pm
What's next for DC. My guess is that they will keep their program active at least until April 28, 2015 when CRS2 is awarded. This should also allow them to finish their CCCtCap milestones.

In my opinion, they also need to find an investor for DC like Jeff Bezos or Paul Allen in order to complete at least one uncrewed demo flight.

Please excuse my ignorance but for what purpose will CRS2 be for?

CRS2 is the program for commercial resupply of ISS after the current CRS flights are complete.

Spacex and Orbital are heavy favorites to win, but the program is open to others.

http://forum.nasaspaceflight.com/index.php?topic=34093.0
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: yg1968 on 09/17/2014 06:09 pm
This is a rumour but it kinds of confirms what Chris is reporting in his latest article:
https://twitter.com/TheLurioReport/status/512292169840099329
Quote
CCtCap rumor1: Was to be SpaceX/SNC at about $5b total until the announcement delay about 2 wks ago. No disrespect Boeing but what happened?

Quote
CCtCap rumor2: ULA stunned at Boeing selection-based on proposal, had concluded dead in water. Again:No disrespect Boeing but what happened?
https://twitter.com/TheLurioReport/status/512293986602848256

If the first tweet rumor is true, I suspect that the only way that SNC could have gotten to a $2.4B price tag is if they used the F9.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: billh on 09/17/2014 06:18 pm
This is a rumour but it kinds of confirms what Chris is reporting in his latest article:
https://twitter.com/TheLurioReport/status/512292169840099329
Quote
CCtCap rumor1: Was to be SpaceX/SNC at about $5b total until the announcement delay about 2 wks ago. No disrespect Boeing but what happened?

Quote
CCtCap rumor2: ULA stunned at Boeing selection-based on proposal, had concluded dead in water. Again:No disrespect Boeing but what happened?
https://twitter.com/TheLurioReport/status/512293986602848256

If the first tweet rumor is true, I suspect that the only way that SNC could have gotten to a $2.4B price tag is if they used the F9.

That would also dovetail nicely with the second rumor, because the implications of a Boeing/Atlas win vs. a Sierra/F9 win would be huge for ULA.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Jarnis on 09/17/2014 06:24 pm
...or they could better afford the ULA launchers because their proposal was based on reusable spacecraft(s), rather than building 8 copies of the thing.

Granted, this would go with a risk on refurbishment costs.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: GreenShrike on 09/17/2014 07:34 pm
...or they could better afford the ULA launchers because their proposal was based on reusable spacecraft(s), rather than building 8 copies of the thing.

Granted, this would go with a risk on refurbishment costs.

I wonder how that played into their CRS2 bid -- would a refurb'd Dream Chaser on a Falcon 9 cost less than a freshly-built Cygnus on an Antares?

Though I suppose that Cygnus, let alone the enhanced version, has DC beat all hollow on pressurized volume, and DC's advantage, down mass, is already covered, if less gently, by Dragon. I guess that DC would then be more suitable to take Dragon's slot, but Dragon can also carry up and dispose of unpressurized cargo.

Overall, I guess Cygnus and Dragon are actually quite synergistic; DC wouldn't be a drop in replacement for either, more's the pity.  :-\
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: yg1968 on 09/18/2014 02:07 pm
I wonder if DC will dump the Atlas V now that they have not been selected. The price of Atlas V seems expensive for a company that is short on funds. I suppose that they will keep the Atlas V as their baseline LV for CRS2. But after that I could see them switch to the Falcon 9.

SNC has booked an Atlas V for 2016. I wonder if they will sell that flight off (is that even allowed?) or try to obtain a reimbursement from ULA. I suppose that they could keep it. But again that seems expensive for a company that will no longer receive funding.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Paul Adams on 09/18/2014 02:21 pm
I worked with a former Boeing manager who told me outright that he had written a number of letters to politicians stating that if they did not win such-and-such contract the result would be so many redundancies in their area. It was/is fully accepted procedure in Boeing and I'm sure many companies do such.

If anyone thinks that politics did not play a BIG part in the selection, and any last minute change, they are kidding themselves.

For the moment we have to continue with old space and legacy mentality, and the US taxpayer will not get value for money. Time is changing that however, no matter how much certain people may protest.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Rocket Science on 09/18/2014 02:24 pm
I wonder if DC will dump the Atlas V now that they have not been selected. The price of Atlas V seems expensive for a company that is short on funds. I suppose that they will keep the Atlas V as their baseline LV for CRS2. But after that I could see them switch to the Falcon 9.

SNC has booked an Atlas V for 2016. I wonder if they will sell that flight off (is that even allowed?) or try to obtain a reimbursement from ULA. I suppose that they could keep it. But again that seems expensive for a company that will no longer receive funding.
I was thinking the same thing last night, but I'm not sure if or what they are allowed to do legally. Then the could book a test flight on an Falcon 9...
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: baldusi on 09/18/2014 02:35 pm
I wonder if DC will dump the Atlas V now that they have not been selected. The price of Atlas V seems expensive for a company that is short on funds. I suppose that they will keep the Atlas V as their baseline LV for CRS2. But after that I could see them switch to the Falcon 9.

SNC has booked an Atlas V for 2016. I wonder if they will sell that flight off (is that even allowed?) or try to obtain a reimbursement from ULA. I suppose that they could keep it. But again that seems expensive for a company that will no longer receive funding.
I was thinking the same thing last night, but I'm not sure if or what they are allowed to do legally. Then the could book a test flight on an Falcon 9...
Well, CST-100 will pay to man-rate the Atlas V, and the Dual Engine Centaur and the Crew Access and Egress tower. And DC already had they tunnel models and a lot of studies done. So I believe that in that sense the incremental cost for SNC of doing an Atlas V mission will be low.
OTOH, I believe that they only have a chance for CRS2. And for that they might just use a 421 and be done with it. It surely is cheaper than a 412 and they can get a great incremental price. But more importantly, as a cargo vehicle they don't need crew access tower, EDS, flat trajectory nor LAS.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: ChrisWilson68 on 09/19/2014 10:05 am
I wonder if DC will dump the Atlas V now that they have not been selected. The price of Atlas V seems expensive for a company that is short on funds. I suppose that they will keep the Atlas V as their baseline LV for CRS2. But after that I could see them switch to the Falcon 9.

SNC has booked an Atlas V for 2016. I wonder if they will sell that flight off (is that even allowed?) or try to obtain a reimbursement from ULA. I suppose that they could keep it. But again that seems expensive for a company that will no longer receive funding.

The usual practice for launch contracts is that the money is due over time as the launch approaches, basically so the launch provider can cover the cost of building the launch vehicle.  At most a small down payment is paid when the contract is signed.

So SNC almost certainly has only paid at most a tiny portion of the cost for this 2016 launch.  They'll probably just walk away from it.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: ChrisWilson68 on 09/19/2014 10:14 am
What's next for DC. My guess is that they will keep their program active at least until April 28, 2015 when CRS2 is awarded. This should also allow them to finish their CCCtCap milestones.

In my opinion, they also need to find an investor for DC like Jeff Bezos or Paul Allen in order to complete at least one uncrewed demo flight.

Maybe not an investor.   It's strange to me that SN didn't court another Nevada company, Bigelow.   Note if you will that Bigelow had some hands in both the SpaceX & Boeing design.

Bigelow makes a lot of noise, but seems to have used up his money (at least that portion of it he's willing to spend on space ventures) with the launch of a couple of small demonstrators.  The company is kind of in hibernation mode, coming out just enough to do BEAM because NASA came up with the money for it.

Bigelow is a sink for money, not a source for it.  Dream Chaser will have to look elsewhere for funding.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: ChrisWilson68 on 09/19/2014 10:21 am
What's next for DC. My guess is that they will keep their program active at least until April 28, 2015 when CRS2 is awarded.

Do we know if Sierra Nevada even submitted a bid for CRS2?  If they figured they'd be busy with CCtCap and weren't a particularly good fit for CRS2, they might not have bid, and it's too late to change that now.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: AnalogMan on 09/19/2014 11:34 am
What's next for DC. My guess is that they will keep their program active at least until April 28, 2015 when CRS2 is awarded.

Do we know if Sierra Nevada even submitted a bid for CRS2?  If they figured they'd be busy with CCtCap and weren't a particularly good fit for CRS2, they might not have bid, and it's too late to change that now.


The final RFP is not due to be released until September 30, with proposals due by November 14, 2014.  So nobody will have submitted any proposals for CRS2 at this point in time.

For schedule see:
http://procurement.jsc.nasa.gov/crs2/schedule.asp (http://procurement.jsc.nasa.gov/crs2/schedule.asp)
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Jim on 09/19/2014 12:07 pm

If anyone thinks that politics did not play a BIG part in the selection, and any last minute change, they are kidding themselves.


No, you really don't know how it works.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Rocket Science on 09/19/2014 12:26 pm
When it comes to Dream Chaser which arose from the HL-20, allow me to quote Spock: "I've been dead before"... ;)
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Nindalf on 09/19/2014 02:39 pm
Constant reframes to new versus old space isn't helpful either.
The barrier has well and truly broken down now anyway, at least in America.  NewSpace isn't just a bunch of hopefuls anymore, they're meshed into the working space industry, with the OldSpace companies tapping them for technology and services.

And let's not forget that despite the David and Goliath hype, Lockheed Martin is a partner in Dream Chaser.  Boeing isn't the only big aerospace company with lots of lobbying power.

I doubt this is the end for Dream Chaser.  More likely, it's just a delay.  It could be good for the vehicle in the long run.  This way, they won't be rushed to get something working even if it means sticking with the problematic hybrid rocket motors.  And as the price for launch services falls, and two American rockets are already being used for crew launch, they won't need NASA money to test it in orbit.

If Dragon V2 had lost out, I'd be saying similar things about it: SpaceX is a big company now, the project will survive, this way they won't be pressured to do parachute assisted landings but can take their time to prove the propulsive landings are reliable, they'll be able to test it more thoroughly and be less likely to have their name stained with a crew loss if they wait to get launch vehicle reusability working, etc.

I feel that CST-100 is the most appropriate design to the Atlas V launch vehicle.  The more ambitious and more reusable Dream Chaser and Dragon V2 both belong on a cheaper launch platform which makes more testing possible, and efficient reusability more relevant.  And this was as much about the robustness of having two launch vehicle options, as it was about having two crew vehicle options.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Nindalf on 09/19/2014 02:59 pm
What I'd really like to see on a liquid-fuelled Dream Chaser is some kind of small air-augmented rocket, air turborocket, or other system, that would make it capable of sustained level flight using the unspent propane/N2O abort propellant, so it's not just a glider.

Maybe they could recover some of their development costs giving people atmospheric or suborbital thrillrides, XCOR Lynx style, but in a real, orbit-capable spacecraft.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: daveklingler on 09/19/2014 05:36 pm
What I'd really like to see on a liquid-fuelled Dream Chaser is some kind of small air-augmented rocket, air turborocket, or other system, that would make it capable of sustained level flight using the unspent propane/N2O abort propellant, so it's not just a glider.

Lovely thought but not technically viable.  And why?  Airplanes are airplanes and spacecraft are spacecraft and east is east and west is west and if you take cranberries and stew them like applesauce they taste much more like prunes than rhubarb does, with apologies to Groucho Marx.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Nindalf on 09/19/2014 07:31 pm
Lovely thought but not technically viable.  And why?  Airplanes are airplanes and spacecraft are spacecraft
By that sort of reasoning, Dream Chaser should not be developed at all.

There are ATR designs with thrust-to-weight ratios quite comparable to rocket engines.  One which is based on an air augmentation concept (using a rocket-like O:F ratio, and gathering air mainly as reaction mass and coolant, instead of as oxidizer), with pressure-fed propellants, should be at the upper end of that range, and very comparable to a pure rocket engine in thrust-to-weight, while having considerably superior Isp (though not as good as a highly fuel-rich ATR).

They can also be quite low in cost, with a castable monorotor on foil bearings.  They're being developed for mass-produced missiles.

There are trade-offs involved, and reasons for them not to do it (increased mass / reduced capacity, one more thing to go wrong, cost, time), and it might not be economically viable, but it's not as simple as "not technically viable".  It would be technically viable to stick a turbojet on it, if you really wanted to.  These were in early Space Shuttle concepts, before it was turned into a performance monster.

This isn't problematic in the same way an airbreathing launch vehicle engine would be (cost-to-thrust vital, needs to be efficient at an extreme variety of altitudes and airspeeds).  This is an airbreathing engine for level tropospheric flight, taking advantage of pressure-fed propellants already present.  Optimized for low altitude, low-speed flying, for powered landing in thick air, so it can be safer and more tolerant of adverse weather conditions.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Nibb31 on 09/20/2014 04:41 am
Yeah but what for? Your air-breathing engines are useless for launch, useless for re-entry, additional mass and additional complexity.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Nindalf on 09/20/2014 05:41 am
Yeah but what for? Your air-breathing engines are useless for launch, useless for re-entry, additional mass and additional complexity.
You could say that about the LAS, the landing gear, and the life support.

If "Lands like an airplane!" is a nice goal, "Lands like an airplane that has not suffered total engine failure!" is an even nicer one.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Rocket Science on 09/22/2014 01:36 pm
Might be interesting for SNC to court some rich oil sheikdoms as investors in an orbital tourism spaceline. It would give them a nice high profile feather in the cap with a unique vehicle that no one else has... Are you listening Mark? ;)
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Paul Adams on 09/22/2014 02:12 pm
Any idea of the sum required to complete and orbit the first vehicle?
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Rocket Science on 09/22/2014 03:02 pm
Any idea of the sum required to complete and orbit the first vehicle?
Somewhere between the cost of an A320-A380 or less than what Ferrari spends to field a non-winning race car in F-1... ;D
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Paul Adams on 09/22/2014 03:04 pm
Amazing isn't' it when you look at it like that - really puts things in perspective.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Pipcard on 09/24/2014 04:14 am
If the launch escape/abort system (very high thrust) doubles as the orbital maneuvering system engines (relatively low thrust), what can be the smallest difference between them? (forget this, this is irrelevant)

For example, if the abort system has 7 Gs of acceleration, and the engines can only have a minimum throttle of 10%, would 0.7 Gs be too much for making changes in your orbit?
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: ChrisWilson68 on 09/24/2014 04:37 am
If the launch escape/abort system (very high thrust) doubles as the orbital maneuvering system engines (relatively low thrust), what can be the smallest difference between them?

For example, if the abort system has 7 Gs of acceleration, and the engines can only have a minimum throttle of 10%, would 0.7 Gs be too much for making changes in your orbit?

If you want to dock or berth with anything in orbit, 0.7g is far, far too much.  There's a reason Dragon has separate Draco and SuperDraco engines, even though they run on the same propellant.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Pipcard on 09/24/2014 06:23 am
If the launch escape/abort system (very high thrust) doubles as the orbital maneuvering system engines (relatively low thrust), what can be the smallest difference between them?

For example, if the abort system has 7 Gs of acceleration, and the engines can only have a minimum throttle of 10%, would 0.7 Gs be too much for making changes in your orbit?

If you want to dock or berth with anything in orbit, 0.7g is far, far too much.  There's a reason Dragon has separate Draco and SuperDraco engines, even though they run on the same propellant.
I was talking about burning to raise your periapsis or apoapsis. Those kinds of maneuvers, not the delicate process of docking.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: guckyfan on 09/24/2014 07:05 am
I was talking about burning to raise your periapsis or apoapsis. Those kinds of maneuvers, not the delicate process of docking.

Dragon is using the Draco for all orbit maneuver. The reason is that they have higher ISP than SuperDraco which are designed to give maximum thrust out of minimum volume, not ISP.

The same would be true for Dream Chaser. Probably even more so if you throttle to 10%.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Pipcard on 09/24/2014 11:38 am
So the main engines would have no use outside of abort situations?
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Nibb31 on 09/24/2014 12:41 pm
So the main engines would have no use outside of abort situations?

..or station reboost.

But yes, that's why traditionally LAS designs get rid of the extra weight when they are no longer needed.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Pipcard on 09/24/2014 12:46 pm
So the main engines would have no use outside of abort situations?

..or station reboost.

But yes, that's why traditionally LAS designs get rid of the extra weight when they are no longer needed.
Except the docking port being on the same side as the engines makes reboost impossible.

Can you have "jettisonable engines" for a spacecraft like this?

Or can you have a safe abort with less than 7 Gs in order to have less engine mass?
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Nibb31 on 09/24/2014 01:25 pm
The old Atlas had jettisonable engines, so it's certainly possible. I'm not sure you would gain much in this case though.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Pipcard on 09/24/2014 01:47 pm
I just want to know if the minimum G-forces required for a safe abort is 7-8 Gs (http://forum.nasaspaceflight.com/index.php?topic=29417.msg1221447#msg1221447) (from a vehicle with no solid boosters), or if it can be less.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: JasonAW3 on 09/24/2014 04:33 pm
So the main engines would have no use outside of abort situations?

..or station reboost.

But yes, that's why traditionally LAS designs get rid of the extra weight when they are no longer needed.
Except the docking port being on the same side as the engines makes reboost impossible.

Can you have "jettisonable engines" for a spacecraft like this?

Or can you have a safe abort with less than 7 Gs in order to have less engine mass?

What, are you looking at 2 sets of two solids, one on each side on top of the wing and two on the underside?
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Pipcard on 09/24/2014 05:50 pm
Actually, it's because I'm making a lifting body based on JAXA's LIFLEX (http://www.aero.jaxa.jp/eng/publication/magazine/sora/2007_no18/ss2007no18_01.html) for a certain space flight simulator.

This project is not serious, and is just for fun, with a lot of educated guesses for the weights and other things.

The mass of the vehicle is about 9 tonnes. Unlike the DC, it uses hypergolic propellant like the original HL-20. The six main engines are similar to SpaceX's SuperDracos in that they provide lots of thrust (each one has a thrust of 103.9 kN, totaling up to 623.4 kN). This means that the vehicle is able to abort with about 7 Gs of acceleration. But when you're in orbit, and if the hypergolic engines can only throttle to 10% (is that possible? is 5% possible?), that means you have 0.7 G, which is still a lot. That is unless you only use 2 out of 6 engines (0.233 G), but that would mean the 4 remaining engines are for aborts only.

And there will be RCS thrusters, too, don't worry.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: ChrisWilson68 on 09/24/2014 07:18 pm
Actually, it's because I'm making a lifting body based on JAXA's LIFLEX (http://www.aero.jaxa.jp/eng/publication/magazine/sora/2007_no18/ss2007no18_01.html) for a certain space flight simulator.

This project is not serious, and is just for fun, with a lot of educated guesses for the weights and other things.

The mass of the vehicle is about 9 tonnes. Unlike the DC, it uses hypergolic propellant like the original HL-20. The six main engines are similar to SpaceX's SuperDracos in that they provide lots of thrust (each one has a thrust of 103.9 kN, totaling up to 623.4 kN). This means that the vehicle is able to abort with about 7 Gs of acceleration. But when you're in orbit, and if the hypergolic engines can only throttle to 10% (is that possible? is 5% possible?), that means you have 0.7 G, which is still a lot. That is unless you only use 2 out of 6 engines (0.233 G), but that would mean the 4 remaining engines are for aborts only.

And there will be RCS thrusters, too, don't worry.

If you have RCS thrusters, just use them in orbit, don't try to use the big abort engines.  That's what Dragon V2 does.  The SuperDracos aren't used in orbit at all.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Chris Bergin on 09/24/2014 10:12 pm
A number of SNC workers lost their jobs today.

Our thoughts and best wishes go out to them. Let's hope they get to see Dream Chaser fly in space one day, because they will have still been a part of it.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: vt_hokie on 09/25/2014 03:25 am
The ugly real side of today's space program: crushed dreams time and again, layoffs and unemployment for those chasing the dream.  I'm getting tired of this storyline. 

Truly sorry for the SNC employees and I sincerely hope that there are chapters yet to be written in the long and winding HL-20 saga.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: OpsAnalyst on 09/25/2014 04:07 am
Per the Denver Post, Mark Sirangelo confirms layoffs, but indicates Dream Chaser program will continue...

http://www.denverpost.com/business/ci_26599813/sierra-nevada-space-systems-dream-chaser-employees-laid

Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: ChrisWilson68 on 09/25/2014 04:08 am
The ugly real side of today's space program: crushed dreams time and again, layoffs and unemployment for those chasing the dream.  I'm getting tired of this storyline.

Lets keep some perspective here.  You're making it sound like this is the only thing going on right now in the space industry.

This was a contest.  Everyone knew going in that there would only be one or two winners.  It's a bit amazing there are two.  One of the three was always going to go through this.  There were always going to be just as many people losing their jobs.  There were always going to be just as many people seeing the project they worked on cancelled.  That's what everyone signed up for from the start of the commercial crew program.

By all means, lets mourn for the people at SNC that put so much into this and lost.  But lets not act like crushed dreams are the only thing happening in the U.S. space industry.

The real long-term danger here is that we see job losses and cancelled projects as unacceptable.  Silicon Valley has created an enormous burst of innovation that has touched everyone's lives not by seeing failed projects and lost jobs as a sign that something is wrong but as a sign that something is right, that lots of people are getting together to form very risky companies and trying all sorts of innovations.

Lets celebrate that the U.S. space industry is not afraid of taking risks.  That's what's going to drive innovation and take us to the stars.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: vt_hokie on 09/25/2014 04:33 am

Lets celebrate that the U.S. space industry is not afraid of taking risks.  That's what's going to drive innovation and take us to the stars.


Right now I feel like this was all a charade, and Boeing's safe design was always going to win out over a more innovative and admittedly risky approach.  So, at the moment I feel like US space policy won't allow for much risk, as the disruptors and innovators are not the ones getting the funding.  I don't question the case for Boeing's CST-100 within the rigid ISS crew transport requirements, but I'm seeing that it was never a very good basis for trying to spur innovation.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Patchouli on 09/25/2014 05:35 am
If the launch escape/abort system (very high thrust) doubles as the orbital maneuvering system engines (relatively low thrust), what can be the smallest difference between them?

For example, if the abort system has 7 Gs of acceleration, and the engines can only have a minimum throttle of 10%, would 0.7 Gs be too much for making changes in your orbit?

If you want to dock or berth with anything in orbit, 0.7g is far, far too much.  There's a reason Dragon has separate Draco and SuperDraco engines, even though they run on the same propellant.


The Apollo SPS engine had 20,000lbs of thrust and as far as I know could not be throttled which would have given the Apollo spacecraft a thrust of a half G or more depending on fuel load.
The RCS also did not share propellant with the SPS engine similar to the situation with DreamChaser's RCS.

Though I think DC still may share N2O between all systems which might allow the RCS the thrusters to still operate as cold gas if the ethanol is exhausted.


Lets celebrate that the U.S. space industry is not afraid of taking risks.  That's what's going to drive innovation and take us to the stars.


Right now I feel like this was all a charade, and Boeing's safe design was always going to win out over a more innovative and admittedly risky approach.  So, at the moment I feel like US space policy won't allow for much risk, as the disruptors and innovators are not the ones getting the funding.  I don't question the case for Boeing's CST-100 within the rigid ISS crew transport requirements, but I'm seeing that it was never a very good basis for trying to spur innovation.

I have a feeling Boeing probably would have been chosen no matter what being an old school contractor with connections and it could have just as easily been Spacex who got cut.
If not for supply issues with the RD-180 on Atlas SNC's vehicle may have been deemed lower risk as gliding landings are more proven the powered VTOL landings.
The only serious technical issues SNC had was the hybrid engine not performing as good as hoped but this should be less of an issue for an OMS/Abort system then for a sub orbital spacecraft.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: TrevorMonty on 09/25/2014 06:02 am
Per the Denver Post, Mark Sirangelo confirms layoffs, but indicates Dream Chaser program will continue...

http://www.denverpost.com/business/ci_26599813/sierra-nevada-space-systems-dream-chaser-employees-laid
The news is not all bad, layoffs were expected but they are far from winding down the DC development.
I'm picking they are targeting CRS2 contracts. Switching to cargo will save a lot of money, no life support an no LAS required. They maybe able to fly it without the 2 main engines.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: baldusi on 09/25/2014 03:46 pm

Lets celebrate that the U.S. space industry is not afraid of taking risks.  That's what's going to drive innovation and take us to the stars.


Right now I feel like this was all a charade, and Boeing's safe design was always going to win out over a more innovative and admittedly risky approach.  So, at the moment I feel like US space policy won't allow for much risk, as the disruptors and innovators are not the ones getting the funding.  I don't question the case for Boeing's CST-100 within the rigid ISS crew transport requirements, but I'm seeing that it was never a very good basis for trying to spur innovation.
I believe that two issues, when compounded, made it very hard to have two risky innovators. The first is Dragon v2 fully propulsive landing and the possibility of F9R first stage reusability. You can't say they are not betting on one innovator. It is an innovative and risky model. Of course it's scalable on risk, since they can do what they have demonstrated with v1 (ocean landing), can land with parachutes on land or, eventually, fully propulsive. And the F9R can be new core so there's no qualification issues. But if reusable SpaceX could make a better price since they could sell the core service again.
The second issue was the Ukrainian crisis with Russia. The top risk to ISS according to the Risk Matrix is lack of crew access redundancy. Depending on the Russians is the worst risk, given the political situation. Thus, NASA already bet on one innovative, low cost provider with good chances of disruptive results. But the risk to the ISS wrt to the Russians meant that suddenly Boeing traditional and low risk approach was suddenly much more desirable.
What if the Russians don't go with the station after 2020? What if the political situation deteriorates to the point of stopping cooperation? You'd better be sure you have two crewed vehicles.
That's what I think happened with DreamChaser. Dragon v2 was the innovation bet of NASA, and CST-100 was the insurance. Dream Chaser was more expensive and more risky (schedule and technology wise) than Dragon v2, and the Russian situation called for a second "safe" investment.
Basically, NASA did invest on one innovator. It just happened to be SpaceX proposal.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: vt_hokie on 09/25/2014 04:55 pm

Basically, NASA did invest on one innovator. It just happened to be SpaceX proposal.

That's a reasonable take on things, but it just rubs me the wrong way that when you step back and look at the big picture, commercial crew as a whole was supposed to be about innovation, and it's just a small piece of the pie while we spend the bulk of funds on SLS/Orion.  So in the end, SpaceX gets a smaller slice of what was already a very small slice of the pie, while Boeing gets considerably more for its Orion-lite vehicle.  I just don't think the overall picture makes much sense, and I feel NASA is putting too much into white elephants and not enough into more promising high bang for the buck efforts.  But that's a higher level policy discussion.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: baldusi on 09/25/2014 06:31 pm

Basically, NASA did invest on one innovator. It just happened to be SpaceX proposal.

That's a reasonable take on things, but it just rubs me the wrong way that when you step back and look at the big picture, commercial crew as a whole was supposed to be about innovation, and it's just a small piece of the pie while we spend the bulk of funds on SLS/Orion.  So in the end, SpaceX gets a smaller slice of what was already a very small slice of the pie, while Boeing gets considerably more for its Orion-lite vehicle.  I just don't think the overall picture makes much sense, and I feel NASA is putting too much into white elephants and not enough into more promising high bang for the buck efforts.  But that's a higher level policy discussion.
Actually, I believe it is the other way around. It is about covering the ISS requirements. Since they are already doing it, they did tried to promote innovation and commercial contracting. But ISS requirements come first. It is regrettable that this ended the way it did, but it was sort of a logical conclusion given NASA's risk aversion. Yes, it's also counter intuitive that having somebody make a great offer might mean that the most expensive solution would have better chances. But that's how this bidding process worked.
As I've stated before, if Putin's Ukrainian adventure hadn't happened, may be Dream Chaser might have had a chance. On the other hand, if such would have been the case, Congress might have been happy to keep paying the Russians for crew access.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Chris Bergin on 09/25/2014 06:42 pm
We will have an extensive article on the forward path tomorrow.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Patchouli on 09/25/2014 07:05 pm

Lets celebrate that the U.S. space industry is not afraid of taking risks.  That's what's going to drive innovation and take us to the stars.


Right now I feel like this was all a charade, and Boeing's safe design was always going to win out over a more innovative and admittedly risky approach.  So, at the moment I feel like US space policy won't allow for much risk, as the disruptors and innovators are not the ones getting the funding.  I don't question the case for Boeing's CST-100 within the rigid ISS crew transport requirements, but I'm seeing that it was never a very good basis for trying to spur innovation.
I believe that two issues, when compounded, made it very hard to have two risky innovators. The first is Dragon v2 fully propulsive landing and the possibility of F9R first stage reusability. You can't say they are not betting on one innovator. It is an innovative and risky model. Of course it's scalable on risk, since they can do what they have demonstrated with v1 (ocean landing), can land with parachutes on land or, eventually, fully propulsive. And the F9R can be new core so there's no qualification issues. But if reusable SpaceX could make a better price since they could sell the core service again.
The second issue was the Ukrainian crisis with Russia. The top risk to ISS according to the Risk Matrix is lack of crew access redundancy. Depending on the Russians is the worst risk, given the political situation. Thus, NASA already bet on one innovative, low cost provider with good chances of disruptive results. But the risk to the ISS wrt to the Russians meant that suddenly Boeing traditional and low risk approach was suddenly much more desirable.
What if the Russians don't go with the station after 2020? What if the political situation deteriorates to the point of stopping cooperation? You'd better be sure you have two crewed vehicles.
That's what I think happened with DreamChaser. Dragon v2 was the innovation bet of NASA, and CST-100 was the insurance. Dream Chaser was more expensive and more risky (schedule and technology wise) than Dragon v2, and the Russian situation called for a second "safe" investment.
Basically, NASA did invest on one innovator. It just happened to be SpaceX proposal.


I think the risk of going with Spacex and SNC would have been perfectly acceptable as one of the companies certainly would have had a vehicle ready by 2017.
Spacex probably could have been ready by early 2016 if given more money.
Both Spacex and SNC have a very good reputation of staying under budget and meeting deadlines.

As for reboost Dragon probably can do it if parachutes are used during landing DC also could do limited reboost with the forward RCS thrusters if extra RCS propellant was carried.
Worst case Spacex could make a small propulsion module that fits in Dragon's trunk.


Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: adrianwyard on 09/25/2014 08:22 pm
It turns out the Dracos on Dragon dish out 400N where the ATV's larger engines do 490N. Since the ATV is used for ISS reboots (sometimes only two of the four) I wonder if the Dragon DV2 RCS could be used in a pinch too. And if so, perhaps the DC forward RCS engines would be technically able to as well. 

I'm guessing Dragon and DC could need additional fuel tanks which is a big change, but that's less of a change than adding special engines to DC or Dragon's trunk.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: clongton on 09/25/2014 08:32 pm
... commercial crew as a whole was supposed to be about innovation ...

VT that's where the train comes off the tracks. So many people, including myself, became enamored with all the innovation that was happening. But contrary to your statement above, commercial crew was not about innovation. It was about providing a very safe ride to the ISS on a commercially produced spacecraft - period - nothing more. Yes there was innovation, by all three competitors, some it very flashy, ALL of it VERY good. But in the end it was just a question of a ride to ISS - a safe ride.

1. CST-100 had a very conservative design based on the well trusted Apollo OML, only scaled up and will ride on the Atlas-V, using proven 1st and 2nd stage engines.

2. Dragon also has a fairly conservative OML and its version 1 capsule has been to the station and returned several times now and will ride on Falcon 9, using proven 1st and 2nd stage engines.

3. DreamChaser was going to ride on Atlas-V as well but with a rarely used 2nd stage and needed to use its own innovative hybrid engines as a 3rd stage, engines that are truly innovative but are not well received in the industry. And to top it all off at the last minute SNC changed the engine at the last minute to a completely untried liquid design.

Whatever else may be said about the competition results, it goes without saying that NASA chose the 2 most conservative designs from the 3 choices, based on its own VERY narrow criteria. In spite of all the WONDERFUL innovation we have witnessed, that's not what NASA wanted.

DreamChaser, a truly innovative and wonderful spacecraft, didn't make the cut. Had this been an X-Plane competition I would bet she would have been the #1 choice. But all NASA wanted was a safe, conservative taxi ride to the ISS. Innovation was not one of the criteria.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Zed_Noir on 09/25/2014 10:21 pm
...
1. CST-100 had a very conservative design based on the well trusted Apollo OML, only scaled up and will ride on the Atlas-V, using proven 1st and 2nd stage engines.

...

3. DreamChaser was going to ride on Atlas-V as well but with a rarely used 2nd stage and needed to use its own innovative hybrid engines as a 3rd stage, engines that are truly innovative but are not well received in the industry. And to top it all off at the last minute SNC changed the engine at the last minute to a completely untried liquid design.
...
Hmmm, IIRC both the CST-100 & DC uses the DEC upper stage.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: clongton on 09/25/2014 10:24 pm
...
1. CST-100 had a very conservative design based on the well trusted Apollo OML, only scaled up and will ride on the Atlas-V, using proven 1st and 2nd stage engines.

...

3. DreamChaser was going to ride on Atlas-V as well but with a rarely used 2nd stage and needed to use its own innovative hybrid engines as a 3rd stage, engines that are truly innovative but are not well received in the industry. And to top it all off at the last minute SNC changed the engine at the last minute to a completely untried liquid design.
...
Hmmm, IIRC both the CST-100 & DC uses the DEC upper stage.

That may be. I'll have to look again. Thanks
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: vt_hokie on 09/26/2014 12:25 am

DreamChaser, a truly innovative and wonderful spacecraft, didn't make the cut. Had this been an X-Plane competition I would bet she would have been the #1 choice. But all NASA wanted was a safe, conservative taxi ride to the ISS. Innovation was not one of the criteria.

And that's why I think maybe the real problem is that NASA doesn't do X-plane programs anymore.  As I said in another post, I think what I and probably many others liked about Dream Chaser was that it kept alive some vestige at least of the pioneering spirit that NASA once had.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: QuantumG on 09/26/2014 12:38 am
http://aviationweek.com/space/sierra-nevada-continue-dream-chaser-may-protest-contract-award

Quote
He also said the company may file a formal protest of NASA’s decision to reject its commercial crew bid with the U.S. Government Accountability Office. The deadline for a bid protest, which could lead to a reconsideration of the contract awards, is Sept. 26, and Sirangelo suggested Sierra Nevada may have financial and technical grounds for the action. A final corporate decision, in consultation with the company’s lawyers, was planned following a meeting Sept. 25.

Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: SWGlassPit on 09/26/2014 01:53 am
As much as I understand why they might want to, I really hope they don't file a protest. I don't want there to be any more delays to uscv-1 than we've already had from the short funding.

Edit: autocorrect error
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: CameronD on 09/26/2014 03:43 am
Well... It's being reported that Sierra Nevada has laid off 90 employees from the Dream Chaser project following the failure to be selected for the next phase of NASA's Commercial Crew Program.

They're obviously hurting.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: ChrisWilson68 on 09/26/2014 04:01 am
Unfortunately, legal protests of contracting decisions seem to be getting very common.  So this isn't too surprising.  Whoever lost, there was likely to be a protest, slowing down the whole program.  The Blue Origin protest of the 39A award to SpaceX didn't delay things too long, though, so hopefully this protest won't either.

It will be interesting to see their complaint and be able to judge for ourselves its merits.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: ChrisWilson68 on 09/26/2014 04:06 am
A lot of the remaining Dream Chaser jobs might be for the CCiCap milestones that have yet to be completed and for the CCtCap protest and the CRS2 bid.  When the final SNC CCiCap milestone is done, if the CCtCap and CRS2 bid are both lost, we'll probably see a lot more job cuts.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Chris Bergin on 09/26/2014 11:39 am
Yeah, I'm waiting for a call to see if they are protesting or not.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: obi-wan on 09/26/2014 01:48 pm
Yeah, I'm waiting for a call to see if they are protesting or not.
They would have to have received a proposal debrief to have a basis for protest - that would imply the source selection letter is out?
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Chris Bergin on 09/26/2014 02:29 pm
Yeah, I'm waiting for a call to see if they are protesting or not.
They would have to have received a proposal debrief to have a basis for protest - that would imply the source selection letter is out?

That would be my assumption too! Will soon find out I guess!
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: JasonAW3 on 09/26/2014 02:56 pm
I hate to say it, but I think the decision might have come down to the capibility of Reboost of the station.  Neither Dreamchaser nor Dragon have a reboost capibility.  Dragon due to the trunk and no extra fuel beyond what it needed for docking and return.  (The Superdracos are only for EMergency escape and landing)  And teh Dreamchaser's engines faced the wrong way.

The CST-100 has four engines it could use to help reboost the station, should teh Russians either not be able to or choose not to assist in the task.

Pure pragmatism.  I personally like both the Dragon and the Dream Chaser, but the bottom line is did it have all the capibilities that NASA is going to need, and are they likely to in the near future.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: ncb1397 on 09/26/2014 03:18 pm
The CST-100 has four engines it could use to help reboost the station, should teh Russians either not be able to or choose not to assist in the task.

I hope you aren't referring to the 4 RS-88 abort engines.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: avollhar on 09/26/2014 03:21 pm
I hate to say it, but I think the decision might have come down to the capability of Reboost of the station.  Neither Dreamchaser nor Dragon have a reboost capability.  Dragon due to the trunk and no extra fuel beyond what it needed for docking and return. 

What about putting an engine with dedicated fuel *inside* the trunk?

But there is another catch: for station reboost, the thrust should roughly point to the CoG of the ISS stack. Otherwise you will easily saturate the CMGs or burn extra fuel just to keep the attitude stable. ATV is docking at the Zvezda port, so does Progress for reboost. Shuttle did it via PMA-2, also well in line with the general ISS structure (just on the other side).

But Dragon is now commonly berthed at the nadir port of harmony.. certainly not suitable for reboost.
Dragon V2 will have a docking (not berthing) mechanism suited for PMA-2.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: JasonAW3 on 09/26/2014 03:44 pm
The CST-100 has four engines it could use to help reboost the station, should teh Russians either not be able to or choose not to assist in the task.

I hope you aren't referring to the 4 RS-88 abort engines.

No, at least I don't believe so.  I tghought that the CST-100 was to use a rocket powered escape tower as it's escape system.  I was refering to the 4 motors on the bottom os the Service Module.  I thought that they were for use as engines for maneuvering, docking and deorbit burns.  Am I wrong on this?
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Jim on 09/26/2014 03:46 pm
The CST-100 has four engines it could use to help reboost the station, should teh Russians either not be able to or choose not to assist in the task.

I hope you aren't referring to the 4 RS-88 abort engines.

No, at least I don't believe so.  I tghought that the CST-100 was to use a rocket powered escape tower as it's escape system.  I was refering to the 4 motors on the bottom os the Service Module.  I thought that they were for use as engines for maneuvering, docking and deorbit burns.  Am I wrong on this?

CST-100 doesn't have a tower, the 4 thrusters on the bottom of the SM (RS-88) are abort motors.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: JasonAW3 on 09/26/2014 04:03 pm
The CST-100 has four engines it could use to help reboost the station, should teh Russians either not be able to or choose not to assist in the task.

I hope you aren't referring to the 4 RS-88 abort engines.

No, at least I don't believe so.  I tghought that the CST-100 was to use a rocket powered escape tower as it's escape system.  I was refering to the 4 motors on the bottom os the Service Module.  I thought that they were for use as engines for maneuvering, docking and deorbit burns.  Am I wrong on this?

CST-100 doesn't have a tower, the 4 thrusters on the bottom of the SM (RS-88) are abort motors.

Welp, there goes THAT Theory!

    Othere than that, I can't figure why NASA choose the CST-100 over the Dreamchaser.  The only other thing is that Boeing is a going concern having built other manned craft before while SNC is an uncertian quantity quality.                                           
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Jim on 09/26/2014 04:19 pm

Welp, there goes THAT Theory!

    Othere than that, I can't figure why NASA choose the CST-100 over the Dreamchaser.  The only other thing is that Boeing is a going concern having built other manned craft before while SNC is an uncertian quantity quality.                                           

CST-100 has many other thrusters it can use for station reboost
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: rpapo on 09/26/2014 04:51 pm
The only other thing is that Boeing is a going concern having built other manned craft before while SNC is an uncertian quantity quality.
It's not precisely a minor concern...
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: ChrisWilson68 on 09/26/2014 07:34 pm
I hate to say it, but I think the decision might have come down to the capability of Reboost of the station.  Neither Dreamchaser nor Dragon have a reboost capability.  Dragon due to the trunk and no extra fuel beyond what it needed for docking and return. 

What about putting an engine with dedicated fuel *inside* the trunk?

With regard to the CCtCap decision, it doesn't really matter whether SpaceX could come up with a configuration that had reboost capability.  All that matters is whether SpaceX submitted a bid that included reboost capability.  If they didn't and SNC didn't but Boeing did, that could have been a big factor in Boeing's favor.

SpaceX might have figured they had a compelling bid without reboost capability and it detracted from their bid to add it because it would have added cost and/or schedule risk that would hurt their bid.  SpaceX doesn't really have an incentive to hurt their own bid just to give Dream Chaser a better shot at the other award slot, if any, than CST-100.  It might also not have been clear that NASA valued reboost so highly, and it might be that deteriorating relations between the U.S. and Russia between bid time and decision time changed the weighting.

But there is another catch: for station reboost, the thrust should roughly point to the CoG of the ISS stack. Otherwise you will easily saturate the CMGs or burn extra fuel just to keep the attitude stable. ATV is docking at the Zvezda port, so does Progress for reboost. Shuttle did it via PMA-2, also well in line with the general ISS structure (just on the other side).

But Dragon is now commonly berthed at the nadir port of harmony.. certainly not suitable for reboost.
Dragon V2 will have a docking (not berthing) mechanism suited for PMA-2.

Dragon V2 and CST-100 will be docking at the same port, so if CST-100 can do reboost from there, Dragon V2 is in the right position to do it too.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: ChrisWilson68 on 09/26/2014 07:41 pm
Othere than that, I can't figure why NASA choose the CST-100 over the Dreamchaser.  The only other thing is that Boeing is a going concern having built other manned craft before while SNC is an uncertian quantity quality.                                         

NASA might also have decided that a capsule design is inherently safer.  There are failure modes of a spaceplane that a capsule does not have.

The hybrid motors on Dream Chaser also might have been considered an inferior solution.  SNC did decide to ditch them only after its CCtCap bid was submitted.

And then there are all the myriad detailed design decisions.  NASA has had a chance to look at them all in depth in CCiCap.  NASA might have decided it liked more of the detailed decisions by Boeing better than those by SNC.

Or it may be yet other factors we're not aware of.

Lets see when the decision document comes out why NASA says they made this choice.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: tobi453 on 09/26/2014 08:49 pm
James Dean
‏@flatoday_jdean

Sierra Nevada has protested NASA's commercial crew contract awards to Boeing and SpaceX. @usgao must resolve by Jan. 5.

Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Lars-J on 09/26/2014 08:53 pm
James Dean
‏@flatoday_jdean

Sierra Nevada has protested NASA's commercial crew contract awards to Boeing and SpaceX. @usgao must resolve by Jan. 5.

It will be interesting to see the detail about the protest. Was the official selection decision document ever made public?
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: docmordrid on 09/26/2014 09:26 pm
Here's the published story....

Link.... (http://www.floridatoday.com/story/tech/science/space/2014/09/26/sierra-nevada-files-protest-nasa-crew-contract/16283213/)
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: NovaSilisko on 09/26/2014 09:41 pm
Really hope this doesn't disrupt the whole program...
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: QuantumG on 09/27/2014 12:15 am
Really hope this doesn't disrupt the whole program...

I really hope it does.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: rcoppola on 09/27/2014 12:32 am
Really hope this doesn't disrupt the whole program...

I really hope it does.
You know, I must admit, at this point, I'm inclined to agree with you. You can't run around screaming competition, competition, competition.....and then give the most money, to the least competitive bid.

(A huge caveat would be...Was Boeing offering a particular, exclusive capability that could conceivable be valued a Billion dollars above and beyond SNC's Bid? I think not but who am I?)
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: TrevorMonty on 09/27/2014 12:40 am
Hopefully SpaceX will carry on regardless.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Jcc on 09/27/2014 01:18 am
Hopefully SpaceX will carry on regardless.

SpaceX will continue. Reismann said that they already had people working the next steps beyond CCiCAP, including " bending metal", even before the award announcement. They don't plan on slowing down.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: R7 on 09/27/2014 02:19 pm
The hybrid motors on Dream Chaser also might have been considered an inferior solution.  SNC did decide to ditch them only after its CCtCap bid was submitted.

Surely the change altered the bid so that NASA had to contemplate the new Orbitec powered DC against others instead of the original hybrid DC? Otherwise it doesn't make much sense; if NASA would have OKd the hybrid DC then what? SNC replies "Thanks ... but sorry that is no longer on the table".

In any case the change must have sent strong bad vibes and the replacement isn't exactly a pillar of mature flight-proven technology either. AFAIK the vortex combustor is neat curiosity which so far has run on small test-stand engines and powered a sounding rocket flight. It's a looooooong step from that to prove that it is safe and reliable enough to propel manned spacecraft.

All in all ISTM the propulsion was probably DC's biggest technical undoing.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: clongton on 09/27/2014 09:32 pm
I hate to say it, but I think the decision might have come down to the capability of Re-boost of the station. 

That would be illegal as it was not one of the requirements.
If that was the deciding factor in Boeing vs. SNC then SNC has a major point in its favor.

Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: joek on 09/27/2014 10:55 pm
I hate to say it, but I think the decision might have come down to the capability of Re-boost of the station. 
That would be illegal as it was not one of the requirements.
If that was the deciding factor in Boeing vs. SNC then SNC has a major point in its favor.

I would not go so far as to say it would be illegal, as the CCtCap solicitation provides for consideration of capabilities "in excess of NASA requirements ..." with evaluation based on "... its values to the Government for a robust design and an operational concept that increase reliability, lower risks, enhance operational flexibility and/or mission performance".

The value of such "excess capability" is certainly subject to interpretation, and could be one source of SNC's challenge--although I doubt it is the primary source, as Boeing and the selection committee would have to show (and presumably could) that excess capability did not increase cost, time or risk.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: MP99 on 09/28/2014 10:00 am
I hate to say it, but I think the decision might have come down to the capability of Re-boost of the station. 
That would be illegal as it was not one of the requirements.
If that was the deciding factor in Boeing vs. SNC then SNC has a major point in its favor.

I would not go so far as to say it would be illegal, as the CCtCap solicitation provides for consideration of capabilities "in excess of NASA requirements ..." with evaluation based on "... its values to the Government for a robust design and an operational concept that increase reliability, lower risks, enhance operational flexibility and/or mission performance".

The value of such "excess capability" is certainly subject to interpretation, and could be one source of SNC's challenge--although I doubt it is the primary source, as Boeing and the selection committee would have to show (and presumably could) that excess capability did not increase cost, time or risk.
I'm wondering how NASA could pay for reboost service?

CCtCap includes an element of cargo. The mass of any prop used in reboost should count as cargo upmass. As a dense cargo, this would make it possible for the spacecraft to carry more mass in its relatively constrained volume.

Cheers, Martin
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: clongton on 09/28/2014 01:58 pm
I have examined the CCtCap RFQ and related Solicitation documentation once again and Station Re-boost is NOT a requirement to be met. All competitors are allowed however to offer additional services beyond the ISS DRM for which CCtCap is designed. They are called Post Mission Capability (PMC). They must however be SEPARATELY bid and are NOT to be part of the decisional process for awarding the ISS DRM CCtCap awards. Because station re-boost is NOT part of the ISS DRM for CCtCap, my understand therefore is that NASA cannot consider station re-boost in determining the CCtCap award winner(s). Any of the contestants may offer station re-boost capability but that proposal must be outside of and subsequent to the CCtCap awards. Only the winner(s) of the CCtCap ISS DRM award may offer this proposal, outside of and subsequent to winning the contract. The PMC proposal for Station re-boost capability may NOT be considered in determining the CCtCap award winner(s).

If NASA selected Boeing over SNC because CST-100 could offer station re-boost and DreamChaser could not, then that is decidedly illegal and may invalidate the entire award.

Edit: I stress that we do NOT know whether or not station re-boost was so considered, so the above is offered purely for informational purposes, because the subject keeps coming up.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: TrevorMonty on 09/28/2014 07:25 pm
The selection decision must also ignore DC horizontal low G landing and Dragon's trunk for unpressurized cargo.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: MP99 on 09/28/2014 08:08 pm
I have examined the CCtCap RFQ and related Solicitation documentation once again and Station Re-boost is NOT a requirement to be met. All competitors are allowed however to offer additional services beyond the ISS DRM for which CCtCap is designed. They are called Post Mission Capability (PMC). They must however be SEPARATELY bid and are NOT to be part of the decisional process for awarding the ISS DRM CCtCap awards. Because station re-boost is NOT part of the ISS DRM for CCtCap, my understand therefore is that NASA cannot consider station re-boost in determining the CCtCap award winner(s). Any of the contestants may offer station re-boost capability but that proposal must be outside of and subsequent to the CCtCap awards. Only the winner(s) of the CCtCap ISS DRM award may offer this proposal, outside of and subsequent to winning the contract. The PMC proposal for Station re-boost capability may NOT be considered in determining the CCtCap award winner(s).

If NASA selected Boeing over SNC because CST-100 could offer station re-boost and DreamChaser could not, then that is decidedly illegal and may invalidate the entire award.

Edit: I stress that we do NOT know whether or not station re-boost was so considered, so the above is offered purely for informational purposes, because the subject keeps coming up.
Thanks, Chuck, that's very helpful.

Edit: I thought they couldn't be considered, then discussion seemed to suggest they could be.

Cheers, Martin
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: QuantumG on 09/30/2014 01:05 am
http://www.sncorp.com/press_more_info.php?id=635

Quote
Sierra Nevada Corporation to Introduce Dream Chaser®
Global Project Spaceflight Program Sept. 30

SPARKS, Nev. (Sept. 29, 2014) – Sierra Nevada Corporation (SNC) is pleased to announce it will be presenting an overview of its Global Project spaceflight program Tuesday, Sept. 30 at 11:45 a.m. EST at the 65th International Astronautical Congress (IAC) in Toronto. The Global Project offers clients a unique turn-key spaceflight capability based on SNC’s Dream Chaser crewed space vehicle.

SNC’s Global Project offers clients across the globe access to low Earth orbit (LEO) without the time, resources and financial burden of developing the necessary capabilities or infrastructure to support a mature human spaceflight program. The Global Project utilizes the Dream Chaser spacecraft as a baseline vehicle which, in turn, can be customized by the client for an array of missions to support government, commercial, academic and international goals. The individual mission customization of the Global Project can be applied to both crewed and uncrewed variants for a single dedicated mission or suite of missions.

“The SNC Global Project provides, for the first time in history, an unprecedented and unique set of spaceflight opportunities for clients around the world,” said John Roth, vice president of business development for SNC’s Space Systems. “SNC is offering access to crewed or uncrewed space missions that include an optionally-piloted space vehicle, a launch vehicle or choice of launch vehicles, and the supporting infrastructure and systems required for such a valuable program. The Global Project offers a client the opportunity to leverage and expand its local technology and industrial base by engaging government research and development laboratories, aerospace industry and universities in developing payloads, vehicle modifications, and ground processing capabilities in support of the selected LEO missions. This program will literally make space accessible to people all over the world, enabling those who have only dreamed about going to space to finally achieve it.”

In addition to offering customized access to LEO as part of the Global Project, SNC has also developed a tailored, world-class training program based on NASA’s strict certification standards that includes preparation for crewed flights, payload and vehicle safety operations. Dream Chaser astronauts undergo training at SNC’s Dream Chaser Training Facility and Space Operations Center. Individuals complete pre-flight, ground, payload and mission control training, and obtain mission briefings in addition to other necessary training as determined by the mission. SNC can also assist clients in setting up in-country training programs as needed.

SNC presents more detailed information on the Dream Chaser Global Project at the 65th IAC in Toronto, Sept. 30, 2014 at 11:45 a.m. EST.

The Dream Chaser is a reusable, lifting-body spacecraft capable of crewed or autonomous flight. Dream Chaser is the only lifting-body spacecraft capable of a runway landing anywhere in the world.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: clongton on 09/30/2014 01:26 am
http://www.sncorp.com/press_more_info.php?id=635

Sierra Nevada Corporation to Introduce Dream Chaser®
Global Project Spaceflight Program Sept. 30

Nice. Looks like SNC has no intention of slipping quietly into the night. :)
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Rocket Science on 09/30/2014 12:38 pm
http://www.sncorp.com/press_more_info.php?id=635

Quote
Sierra Nevada Corporation to Introduce Dream Chaser®
Global Project Spaceflight Program Sept. 30

SPARKS, Nev. (Sept. 29, 2014) – Sierra Nevada Corporation (SNC) is pleased to announce it will be presenting an overview of its Global Project spaceflight program Tuesday, Sept. 30 at 11:45 a.m. EST at the 65th International Astronautical Congress (IAC) in Toronto. The Global Project offers clients a unique turn-key spaceflight capability based on SNC’s Dream Chaser crewed space vehicle.

SNC’s Global Project offers clients across the globe access to low Earth orbit (LEO) without the time, resources and financial burden of developing the necessary capabilities or infrastructure to support a mature human spaceflight program. The Global Project utilizes the Dream Chaser spacecraft as a baseline vehicle which, in turn, can be customized by the client for an array of missions to support government, commercial, academic and international goals. The individual mission customization of the Global Project can be applied to both crewed and uncrewed variants for a single dedicated mission or suite of missions.

“The SNC Global Project provides, for the first time in history, an unprecedented and unique set of spaceflight opportunities for clients around the world,” said John Roth, vice president of business development for SNC’s Space Systems. “SNC is offering access to crewed or uncrewed space missions that include an optionally-piloted space vehicle, a launch vehicle or choice of launch vehicles, and the supporting infrastructure and systems required for such a valuable program. The Global Project offers a client the opportunity to leverage and expand its local technology and industrial base by engaging government research and development laboratories, aerospace industry and universities in developing payloads, vehicle modifications, and ground processing capabilities in support of the selected LEO missions. This program will literally make space accessible to people all over the world, enabling those who have only dreamed about going to space to finally achieve it.”

In addition to offering customized access to LEO as part of the Global Project, SNC has also developed a tailored, world-class training program based on NASA’s strict certification standards that includes preparation for crewed flights, payload and vehicle safety operations. Dream Chaser astronauts undergo training at SNC’s Dream Chaser Training Facility and Space Operations Center. Individuals complete pre-flight, ground, payload and mission control training, and obtain mission briefings in addition to other necessary training as determined by the mission. SNC can also assist clients in setting up in-country training programs as needed.

SNC presents more detailed information on the Dream Chaser Global Project at the 65th IAC in Toronto, Sept. 30, 2014 at 11:45 a.m. EST.

The Dream Chaser is a reusable, lifting-body spacecraft capable of crewed or autonomous flight. Dream Chaser is the only lifting-body spacecraft capable of a runway landing anywhere in the world.
Will it be streamed?
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: The Amazing Catstronaut on 09/30/2014 05:38 pm
http://www.sncorp.com/press_more_info.php?id=635

Sierra Nevada Corporation to Introduce Dream Chaser®
Global Project Spaceflight Program Sept. 30

Nice. Looks like SNC has no intention of slipping quietly into the night. :)

Hopefully they slip loudly into the night, roaring skyward on a core with legs.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Hauerg on 09/30/2014 05:52 pm
http://www.sncorp.com/press_more_info.php?id=635

Sierra Nevada Corporation to Introduce Dream Chaser®
Global Project Spaceflight Program Sept. 30

Nice. Looks like SNC has no intention of slipping quietly into the night. :)

Hopefully they slip loudly into the night, roaring skyward on a core with legs.

DC on F9(R) will be discussed between SNC and spaceX only after DC has lost her appeal.
Methinks.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Stellvia on 10/01/2014 12:03 am
http://www.sncorp.com/press_more_info.php?id=636

Quote
SPARKS, Nev. (Sept. 30, 2014) – Sierra Nevada Corporation (SNC) today announced a design for an integrated system for human spaceflight that can be launched to low Earth orbit (LEO) using Stratolaunch System’s air launch architecture and a scale version of SNC’s Dream Chaser® spacecraft.

The Dream Chaser is a reusable, lifting-body spacecraft capable of crewed or autonomous flight. Dream Chaser is the only lifting-body spacecraft capable of a runway landing, anywhere in the world. Stratolaunch Systems is a Paul G. Allen project dedicated to developing an air-launch system that will revolutionize space transportation by providing orbital access to space at lower costs, with greater safety and more flexibility.

As designed, the Dream Chaser-Stratolauncher human spaceflight system can carry a crew of three astronauts to LEO destinations. This versatile system can also be tailored for un-crewed space missions, including science missions, light cargo transportation or suborbital point-to-point transportation. The scaled crewed spacecraft design is based on SNC’s full-scale Dream Chaser vehicle which, for the past four years, has undergone development and flight tests as part of NASA’s Commercial Crew Program.

Chuck Beames, president, Vulcan Aerospace Corp and executive director for Stratolaunch Systems said, “Combining a scaled version of SNC’s Dream Chaser with the Stratolaunch air launch system could provide a highly responsive capability with the potential to reach a variety of LEO destinations and return astronauts or payloads to a U.S. runway within 24 hours.”

“This relationship would expand our portfolio to include the highly flexible Stratolaunch system for launching reusable crewed or uncrewed spacecraft, or for rapid satellite constellation deployment,” said Mark Sirangelo, corporate vice president of SNC’s Space Systems.

In addition to supporting development of human spaceflight capability, SNC studied satellite launch options and mechanisms, as well as point-to-point transportation options using the Stratolaunch launch system with a Dream Chaser spacecraft derivative. The Stratolaunch system is uniquely designed to allow for maximum operational flexibility and payload delivery from several possible operational sites, while minimizing mission constraints such as range availability and weather.

SNC and Stratolaunch Systems will present more detailed information on Dream Chaser-Stratolauncher at the 65th International Astronautical Congress in Toronto, Canada, on October 1, 2014 at 9:45 am ET in Room 701B.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Rocket Science on 10/01/2014 12:07 am
Like Spock said... I've been dead before... ;)
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Nindalf on 10/01/2014 12:18 am
I like it.  Stratolaunch with Dream Chaser is a good pairing.  They can take off from the same places as SpaceShipTwo, and if something goes wrong when they light the candle, they don't have that awkwardness of being near ground level in a glider.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Rocket Science on 10/01/2014 12:29 am
Remember how we talked about this combo a couple of years back? :)
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: QuantumG on 10/01/2014 12:41 am
Correct me if I'm wrong, but theoretically this combination would have many more opportunities for fast rendezvous with the ISS than a ground launched vehicle, yes?
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: adrianwyard on 10/01/2014 12:50 am
I like it.  Stratolaunch with Dream Chaser is a good pairing.  They can take off from the same places as SpaceShipTwo, and if something goes wrong when they light the candle, they don't have that awkwardness of being near ground level in a glider.

...you do have to consider what the spent launch vehicle stages will flatten, so you can't fly from any place, any time.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: adrianwyard on 10/01/2014 12:59 am
This announcement finally makes the sub-orbital point-to-point discussion official - this has frequently been discussed in the past wrt Dream Chaser. I imagine the Stratolaunch system as conceived could do it, but who would pay the substantial price for such a service?

I noticed that Richard Branson continues to talk about point-to-point services, which makes no sense for SS2. Perhaps VG could team with Stratolaunch/DC?

I wonder what would Virgin Galactic would charge for a 30 minute hypersonic flight from Florida to London?
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Chris Bergin on 10/01/2014 01:00 am
So I'm hoping we'll get to see some visuals.

I assume they will be forthcoming at this event tomorrow:

SNC and Stratolaunch Systems will present more detailed information on Dream Chaser-Stratolauncher at the 65th International Astronautical Congress in Toronto, Canada, on October 1, 2014 at 9:45 am ET in Room 701B.

Any one know if it's webcast?
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Nindalf on 10/01/2014 01:15 am
I like it.  Stratolaunch with Dream Chaser is a good pairing.  They can take off from the same places as SpaceShipTwo, and if something goes wrong when they light the candle, they don't have that awkwardness of being near ground level in a glider.

...you do have to consider what the spent launch vehicle stages will flatten, so you can't fly from any place, any time.
Pegasus II has wings.  Don't they get to ditch the stages where they want them?

Anyway, I assume SpaceShipTwo has got similar safety constraints on where they can crash their flaming debris separate and proceed on rocket power.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: enkarha on 10/01/2014 01:56 am
The Stratolaunch version DC is going to have to be pretty darn tiny- probably just a bit bigger than the X-37b, maybe 80% of what it is now on all sides. Cute.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: docmordrid on 10/01/2014 03:16 am
"X-37C" = DC-mini in drag?
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Lars-J on 10/01/2014 04:51 am
The Stratolaunch version DC is going to have to be pretty darn tiny- probably just a bit bigger than the X-37b, maybe 80% of what it is now on all sides. Cute.

Yeah, Stratolaunch - as we know it - Can only do ~6 mt to LEO. You probably want twice that. But how? It already uses two massive SRB stages plus a dual RL-10 third stage.

How will it be done?
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: yg1968 on 10/01/2014 04:59 am
So I'm hoping we'll get to see some visuals.

I assume they will be forthcoming at this event tomorrow:

SNC and Stratolaunch Systems will present more detailed information on Dream Chaser-Stratolauncher at the 65th International Astronautical Congress in Toronto, Canada, on October 1, 2014 at 9:45 am ET in Room 701B.

Any one know if it's webcast?

I don't think so. It seems that some space media will be there. However, it might be posted on their youtube channel a couple of months from now:

http://www.iafastro.org/events/iac/iac-2014/
http://www.iac2014.org/

https://www.youtube.com/user/iafastro
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Rocket Science on 10/01/2014 07:09 am
Remember my thread on DC's ancestor concept "Yellowbird" from 50 years back? It was a 3 person spacecraft that might provide a sense of scale...

http://forum.nasaspaceflight.com/index.php?topic=27178.0
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Lars-J on 10/01/2014 07:27 am
Remember my thread on DC's acestor concept "Yellowbird" from 50 years back? It was a 3 person spacecraft that might provide a sense of scale...

http://forum.nasaspaceflight.com/index.php?topic=27178.0

But that's not DC. Not even close.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: ChrisWilson68 on 10/01/2014 07:30 am
SNC has been talking about doing crew for other governments for years.  I have yet to see any other government indicate an interest in paying for Dream Chaser's development.  Governments just don't fund big technology development projects for foreign companies.  If a foreign government really wanted to pay a company in a different country to fly its people to space, they could pay SpaceX or Boeing -- or Roscosmos for that matter -- much less to do so.

About pairing a mini Dream Chaser with Stratolaunch --who's going to pay for that?

Neither of these announcements solves Dream Chaser's fundamental problem: nobody with enough money is willing to spend it to finish the crewed Dream Chaser's development.

The only real hope crew Dream Chaser has is winning its CCtCap protest.  Since we haven't seen the selection document, we don't know NASA's justification for the choice, so it's extremely hard to judge how big a chance that is.

Cargo Dream Chaser has a remote chance with CRS2.  Very unlikely, I think, but more likely than getting a foreign government to fund crew Dream Chaser or getting anyone at all to fund mini-DC on Stratolaunch.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Nibb31 on 10/01/2014 08:34 am
Wouldn't a "scaled-down" Dream Chaser put them back to square one? The only thing in common would be  the old HL20/X-38 moldline that they licensed from NASA. All the rest would have to be redesigned and rebuilt from scratch.

It also poses the question of the purpose. Access to the ISS is done. Tourism? Scaling it down means scaling down the passenger capability to 3 or 4, which makes tourist seats more expensive. Unless Bigelow suddenly finds customers for his station, there is no destination in LEO for a private crew vehicle to fly to.

And well, I have some serious doubts about the economical viability of Stratolaunch, a one-off aircraft that is likely to be the most expensive first-stage on the market. It also raises some questions about abort and scrub modes, especially on a manned vehicle.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: acrotti on 10/01/2014 08:39 am
Hello all, this is my first post, after about 4 years voyeuring NSF forums ;-)

SNC announcement is really intriguing. I agree with Chris Wilson about the funding issue but, forgetting it for a while, I think that the scaled down version of DC may have the following characteristic:
- exactly the same dimensions and body (modifying it, means redesigning the whole thing from scratch: too expensive and time consuming)
- switch to the new liquid propulsion
- moving the docking hatch above the cabin (the only external modification)
- utilize half of the internal space (the rear half) to add more fuel/oxidizer tanks.
With more fuel, DC will act as the last stage of the launch vehicle (think about the OMS of the Space Shuttle) thus allowing Stratolaunch to carry more than 6t to orbit (but loosing DC internal space and reducing the seats to 3).
I've made no calculations on this, therefore I cannot be sure that it will work, but many of you are strong on this. So, if you want to check it numerically...
Ciao (this forum is awesome!)
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Rocket Science on 10/01/2014 08:49 am
Remember my thread on DC's acestor concept "Yellowbird" from 50 years back? It was a 3 person spacecraft that might provide a sense of scale...

http://forum.nasaspaceflight.com/index.php?topic=27178.0

But that's not DC. Not even close.
Yellowbird was Martin... NASA Langley followed on with it as the HL-10 flight test program (built by Northrop for them) while Martin developed the PRIME /X-23/X-24A. Langley developed it further as the HL-20 with the (BOR) melding of the designs... Then we have SNC refining it further as DC and is being built by Lockheed Martin. Are the Apollo CM and CST-100 identical, no but they share the same lineage...
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Rocket Science on 10/01/2014 08:52 am
Hello all, this is my first post, after about 4 years voyeuring NSF forums ;-)

SNC announcement is really intriguing. I agree with Chris Wilson about the funding issue but, forgetting it for a while, I think that the scaled down version of DC may have the following characteristic:
- exactly the same dimensions and body (modifying it, means redesigning the whole thing from scratch: too expensive and time consuming)
- switch to the new liquid propulsion
- moving the docking hatch above the cabin (the only external modification)
- utilize half of the internal space (the rear half) to add more fuel/oxidizer tanks.
With more fuel, DC will act as the last stage of the launch vehicle (think about the OMS of the Space Shuttle) thus allowing Stratolaunch to carry more than 6t to orbit (but loosing DC internal space and reducing the seats to 3).
I've made no calculations on this, therefore I cannot be sure that it will work, but many of you are strong on this. So, if you want to check it numerically...
Ciao (this forum is awesome!)
Welcome to the Forum! :) We will find out in only a few hours...
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: baddux on 10/01/2014 08:56 am
How high could DC+stratolaunch go for a suborbital flight? I think the travel from point to point will never be viable with non-reusable rocket but if you could go to 2000km it would be cooler trip than couple of orbits in 200km.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Nibb31 on 10/01/2014 09:05 am
A suborbital flight with a 2000km apogee would make a pretty high-g reentry. I don't think DreamChaser is designed for that sort of thing.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Mike Harris-Stone on 10/01/2014 10:16 am
SNC has been talking about doing crew for other governments for years.  I have yet to see any other government indicate an interest in paying for Dream Chaser's development.  Governments just don't fund big technology development projects for foreign companies.  If a foreign government really wanted to pay a company in a different country to fly its people to space, they could pay SpaceX or Boeing -- or Roscosmos for that matter -- much less to do so.

About pairing a mini Dream Chaser with Stratolaunch --who's going to pay for that?

Neither of these announcements solves Dream Chaser's fundamental problem: nobody with enough money is willing to spend it to finish the crewed Dream Chaser's development.

The only real hope crew Dream Chaser has is winning its CCtCap protest.  Since we haven't seen the selection document, we don't know NASA's justification for the choice, so it's extremely hard to judge how big a chance that is.

Cargo Dream Chaser has a remote chance with CRS2.  Very unlikely, I think, but more likely than getting a foreign government to fund crew Dream Chaser or getting anyone at all to fund mini-DC on Stratolaunch.

I'm not so sure.  The way you are arguing it, SNC's biggest problem is coming up with enough development money to finish DC.  That might be true if SNC were a start up and DC was their ONLY business, but that isn't the case with SNC at all.  They are a good size, privately owned profitable company with plenty of established business units.  They have pursued Commercial Crew with a vision of there being a new, opening commercial market for manned space flight.  As a successful business, I don't think they would have done this without doing some homework first.  (though I could be wrong)  They've know all along that not getting the contract was possible, yet they've invested their own money in it and when others (i.e. Boeing) where laying off employees -- they were acquiring other companies. 

Look at it this way, companies raise capital all the time and SNC certainly has some of it's own.  There is enough money out there to get DC into orbit.  Paul Allen by himself probably has enough money to get DC into orbit.  What SNC needs in a nutshell is customers -- it needs to know that they will come if they build it.  Price is a factor here as well as demand.  They are already way out ahead with their agreements with Japan and ESA.  So while I agree with you that other countries may not want to fund development, I don't think that's the bpttpm line.  The real issue is having a market.  If SNC can establish that there is a market for their Global Services, then I think you will see them flying in the near future...maybe even BEFORE Boeing, on their own dime.  If they can't find customers, and it's clear that there is no market or viable business model without NASA as a tent-pole customer...then that may be it.

Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Chris Bergin on 10/01/2014 01:37 pm
So if everyone can keep an eye on media coverage of the event today and collate it into here, we'll see what gets put out there. I'll write an article and mix in some additional stuff later today.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Stellvia on 10/01/2014 01:45 pm
So if everyone can keep an eye on media coverage of the event today and collate it into here, we'll see what gets put out there. I'll write an article and mix in some additional stuff later today.

Alan Boyle is on the case, with an image of the Space Goose/DreamChaser combo:-

http://www.nbcnews.com/science/space/sierra-nevada-stratolaunch-team-dream-chaser-space-plane-n215386
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: yg1968 on 10/01/2014 02:23 pm
AVweek also has an article:
http://aviationweek.com/space/sierra-nevada-turns-international-market-dream-chaser
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Rocket Science on 10/01/2014 02:32 pm
AVweek also has an article:
http://aviationweek.com/space/sierra-nevada-turns-international-market-dream-chaser
There we have it 75% scale DC! :)
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: OpsAnalyst on 10/01/2014 02:45 pm
For many years, the Marines and 'special forces' had a chit on the table seeking an operationally-responsive crew transport system to anywhere on the globe for forward deployment of small parties.  It was well-understood that this required suborbital to orbital capability.

From inception it was clear that Stratolauncher's primary target of opportunity was something other than civil applications.

Hmmmm....
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Nibb31 on 10/01/2014 02:55 pm
A 75% scaled DreamChaser would be useless as a military transport. It could only drop 3 or 4 people, a Mach 20 reentry isn't exactly stealthy and it needs a friendly runway large enough to land a C-5 Galaxy to bring it back (does it even fit inside a C-5 ?)
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: abaddon on 10/01/2014 02:58 pm
I really like DreamChaser, but is anyone else as underwhelmed about this as I am?  I have a really hard time seeing this going anywhere.  I am trying not to be negative but this has one of those aerospace "big announcements with grand plans that will inevitably come to nothing" feelings about it for me.

Hope to be proven wrong.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Rocket Science on 10/01/2014 03:07 pm
Can anyone recall if the ETA was full scale to the OTV. The ETA might be bigger that the static mock-up from Langley IIRC. For some reason I keep thinking it may be smaller anyone? Mark always stated he could make many versions in the past...
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Rocket Science on 10/01/2014 03:12 pm
A 75% scaled DreamChaser would be useless as a military transport. It could only drop 3 or 4 people, a Mach 20 reentry isn't exactly stealthy and it needs a friendly runway large enough to land a C-5 Galaxy to bring it back (does it even fit inside a C-5 ?)
It may not be DC the military may want but their own "black" project spaceplane we don't know about...
It could come in under a parafoil like the X-38 no runway needed... ;)

See about 10 min. in video

https://www.youtube.com/watch?v=qp6ygbpungA
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Chris Bergin on 10/01/2014 03:43 pm
So if everyone can keep an eye on media coverage of the event today and collate it into here, we'll see what gets put out there. I'll write an article and mix in some additional stuff later today.

Alan Boyle is on the case, with an image of the Space Goose/DreamChaser combo:-

http://www.nbcnews.com/science/space/sierra-nevada-stratolaunch-team-dream-chaser-space-plane-n215386

Oh my goodness! Now I know what I want for Christmas! ;D

Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Lars-J on 10/01/2014 03:55 pm
So if everyone can keep an eye on media coverage of the event today and collate it into here, we'll see what gets put out there. I'll write an article and mix in some additional stuff later today.

Alan Boyle is on the case, with an image of the Space Goose/DreamChaser combo:-

http://www.nbcnews.com/science/space/sierra-nevada-stratolaunch-team-dream-chaser-space-plane-n215386

Here it is, attached.

But this still makes no sense to me. But then again neither does Stratolaunch. :)

A mini DC (I guess they chuck out all their DC hardware), but you still need a massive aircraft plus 3 expendable stages to get to orbit. In what universe does this look economical?
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: mr. mark on 10/01/2014 03:59 pm
So if everyone can keep an eye on media coverage of the event today and collate it into here, we'll see what gets put out there. I'll write an article and mix in some additional stuff later today.

Alan Boyle is on the case, with an image of the Space Goose/DreamChaser combo:-

http://www.nbcnews.com/science/space/sierra-nevada-stratolaunch-team-dream-chaser-space-plane-n215386


Here it is, attached.

But this still makes no sense to me. But then again neither does Stratolaunch. :)

A mini DC (I guess they chuck out all their DC hardware), but you still need a massive aircraft plus 3 expendable stages to get to orbit. In what universe does this look economical?
Flying this version of DC makes more sense on a Falcon 9.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: TrevorMonty on 10/01/2014 04:00 pm
It could fly on an Antares.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Lars-J on 10/01/2014 04:15 pm
https://twitter.com/jeff_foust/status/517341007596101634

Quote
Jeff Foust ‏@jeff_foust
Gravelle: looked at using Stratolaunch system for suborbital Dream Chaser flghts, including point-to-point missions. #IAC2014

This makes no sense...

Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Nindalf on 10/01/2014 04:49 pm
A mini DC (I guess they chuck out all their DC hardware), but you still need a massive aircraft plus 3 expendable stages to get to orbit. In what universe does this look economical?
Two of the stages are relatively small solid-fuel stages.  The total mass of the rockets is considerably reduced from a ground launch, and they also have no need of a launchpad.

Starting from the reusable aircraft and the reusable spacecraft, with no launch pad needed, they could evolve forward with a liquid-fuelled first stage to replace the two solid-fuel stages, then one that lands on a runway (the solid version already has wings), and then a reusable upper or integrated upper/spacecraft.  They have margin to work with to add reusability since the solid-fuel stages are mass-inefficient.

Orbital ATK also has experience with big liquid boosters.  I bet SNC would love to do a spaceplane upper/spacecraft for them.

All of the people involved in this could put together something just as ambitious as the Falcon 9 reusability plan.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: yg1968 on 10/01/2014 05:06 pm
https://twitter.com/jeff_foust/status/517341007596101634

Quote
Jeff Foust ‏@jeff_foust
Gravelle: looked at using Stratolaunch system for suborbital Dream Chaser flghts, including point-to-point missions. #IAC2014

This makes no sense...

Why not? I am assuming that you wouldn't need the Orbital LV for these suborbital flights.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Lars-J on 10/01/2014 05:13 pm
https://twitter.com/jeff_foust/status/517341007596101634

Quote
Jeff Foust ‏@jeff_foust
Gravelle: looked at using Stratolaunch system for suborbital Dream Chaser flghts, including point-to-point missions. #IAC2014

This makes no sense...

Why not? I am assuming that you wouldn't need the Orbital LV for these suborbital flights.

Then what kind of suborbital flights would they do, and with what? Just dropped from a carrier aircraft?  ;D
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: StealerofSuns on 10/01/2014 05:18 pm
https://twitter.com/jeff_foust/status/517341007596101634

Quote
Jeff Foust ‏@jeff_foust
Gravelle: looked at using Stratolaunch system for suborbital Dream Chaser flghts, including point-to-point missions. #IAC2014

This makes no sense...

Why not? I am assuming that you wouldn't need the Orbital LV for these suborbital flights.

Then what kind of suborbital flights would they do, and with what? Just dropped from a carrier aircraft?  ;D

No, just a smaller "first stage."
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Robotbeat on 10/01/2014 05:29 pm
This is similar in many ways to what XCOR's final plans are. The main difference is the solid rocket stages. Replace that with a high-performance, high-Isp liquid fly back booster (maybe two), expand mini-DC propulsion, and we're in business.

The only way the current setup with the solids makes sense is as a transitional form of a fully reusable crewed LV. DC can serve as it's own upperstage, which is the hardest part to reuse. Hope they announce that next, but I'm not holding my breath.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: mr. mark on 10/01/2014 05:56 pm
"SNC not prepared to discuss propulsion systems for Dream Chaser"
I would say this is an ongoing problem.
source: http://www.parabolicarc.com/2014/10/01/details-dream-chaser-stratolaunch-launch-concept/
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Lars-J on 10/01/2014 06:09 pm
"SNC not prepared to discuss propulsion systems for Dream Chaser"
I would say this is an ongoing problem.
source: http://www.parabolicarc.com/2014/10/01/details-dream-chaser-stratolaunch-launch-concept/

Apparently this version of DC is 75% smaller - this would be dimensions, not mass. Such a scale down would result in a vehicle that has ~42% mass of the original.

It was also compared in size to the Apollo command module, and would be for a crew of 2-3. That's... small. Would they be sitting in a single line?
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Space Ghost 1962 on 10/01/2014 06:13 pm
Hermes (http://forums.macrumors.com/showthread.php?t=1287099&page=39)

(http://www.esa.int/var/esa/storage/images/esa_multimedia/images/2011/03/hermes_1987_concept_for_a_european_manned_spaceplane/10081235-2-eng-GB/Hermes_1987_concept_for_a_European_manned_spaceplane_large.jpg)
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Lars-J on 10/01/2014 06:17 pm
Hermes (http://forums.macrumors.com/showthread.php?t=1287099&page=39)

What does Hermes have to do with a scaled down DC? Hermes was even bigger than the "current" DC.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Space Ghost 1962 on 10/01/2014 06:21 pm
Hermes (http://forums.macrumors.com/showthread.php?t=1287099&page=39)

What does Hermes have to do with a scaled down DC? Hermes was even bigger than the "current" DC.
Started off much smaller/simpler. Look at development history. They solved the same problem as small Dream Chaser, and then had massive mission creep, because they felt pressure to compete with Shuttle.

add:
Originally 3 persons on an Ariane 4 with increasing time on orbit. If you limit the time on orbit, its back to "small" DC and similar issues.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: butters on 10/01/2014 06:28 pm
So they make the spacecraft 75% as large and the launch vehicle still requires two RL-10 engines. Brilliant?

Edit: corrected the description of the scaling factor
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Space Ghost 1962 on 10/01/2014 06:28 pm
I'm still not seeing the connection. Hermes started out bigger than the current DC, and grew. But DC is shrinking, the opposite. So other than both being spaceplaces, what is the connection?
What you do with small size/LV in terms of trades are similar. Also, an example of the trend to cancel when creep/LV overgrowth.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Todd Martin on 10/01/2014 06:31 pm
There are limited choices for SNC in selecting a booster to put DC into orbit:

Atlas V: Pros:  Man rated (or close to it), ready now, already completed wind-tunnel testing & integration issues.  Cons:  Horribly expensive, slated to be retired in favor of new LNG fueled booster, has Russian engines

Falcon 9:  Pros:  Man-rated (or close to it), ready now, cheap.  Cons:  no wind-tunnel tests or integration work complete, SpaceX is in direct competition with Dragon.

Antares:  Pros: ready now.  Cons:   Limited to 6 Tons LEO, Solid upper stage difficult to deliver payload close to target (can't shut it off, always burns to completion), difficult to man-rate, Orbital in competition with Cygnus for cargo, needs wind-tunnel testing & integration work

Delta IV: Pros: ready now, Cons:   Super-Horribly expensive, not man-rated, no wind-tunnel tests or integration work complete.

Arianne V:  Pros: ready now, Cons:  Very expensive, over-sized for DC, not man-rated, no wind-tunnel tests or integration work complete, ITAR issues, NASA contracts generally want launches from U.S. soil.

Proton: Pros: ready now, Cons: Over-size for DC, no wind-tunnel tests or integration work complete, ITAR issues, political issues, NASA contracts generally want launches from U.S. soil.

Soyuz: Pros: ready now, Man-rated, Cheap.  Cons: Only 5.5 Tons to LEO, ITAR issues, political issues, NASA contracts generally want launches from U.S. soil.

H2:  Pros: ready now.  Cons: Over-size for DC, Expensive, ITAR issues, no wind tunnel or integration work complete, NASA contracts generally want launches from U.S. soil.

In comparison, Stratolaunch has some advantages to these choices.  While under-size and needs development work, it is a U.S. booster which is not built by a direct competitor.  The price could be substantially cheaper than other Domestic choices.  There are business opportunities for SNC to improve the Stratolaunch system.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: mheney on 10/01/2014 06:32 pm
Just to make sure there's no confusion - the mini-me version will be 75% the size of the original.  "75% smaller" makes it sound like 1/4 the size.  If the weight scales linearly, it would be (3/4)3, or 27/64 (about 42%) the weight of the original.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: mr. mark on 10/01/2014 06:40 pm
If they commit to this version you can most assuredly say goodbye to the current version on Atlas. SNC does not have the money to develop both lines.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Nibb31 on 10/01/2014 06:55 pm
Starting from the reusable aircraft and the reusable spacecraft, with no launch pad needed, they could evolve forward with a liquid-fuelled first stage to replace the two solid-fuel stages, then one that lands on a runway (the solid version already has wings), and then a reusable upper or integrated upper/spacecraft.  They have margin to work with to add reusability since the solid-fuel stages are mass-inefficient.

Reusable doesn't mean that it's economical. You still have to amortize your development cost on a one-off (or small series) vehicle. A low flight rate makes it a hangar queen, which is losing money. Reusability only makes sense if it's scaled to meet demand.

So what demand is there for a 3-person orbital taxi outside of CCtDev or for 3-person suborbital point-to-point flights? What problem does this vehicle solve?
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: yg1968 on 10/01/2014 06:57 pm
Quote
Since there was some confusion online, I clarified with SNC that the Dream Chaser proposed for Stratolauncher is 75% the size of original.

https://twitter.com/jeff_foust/status/517373287840509954
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Coastal Ron on 10/01/2014 07:23 pm
If they commit to this version you can most assuredly say goodbye to the current version on Atlas. SNC does not have the money to develop both lines.

Not necessarily.  The NASA money from the CCtCap award would likely fund the majority of the development work for Dream Chaser, whereas I would imagine Sierra Nevada is funding 100% of their part of the "Global Project" (i.e. 75% sized Dream Chaser).

However I would not be surprised if SNC has considered flying Dream Chaser on a SpaceX vehicle, and I would not be surprised if SpaceX were open to that.  But that likely won't happen without SNC winning a CCtCap award...
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: ChrisWilson68 on 10/01/2014 07:46 pm
The real issue is having a market.  If SNC can establish that there is a market for their Global Services, then I think you will see them flying in the near future...maybe even BEFORE Boeing, on their own dime.

I agree with you that if they could show a demonstrated market that would make them enough money to pay for development costs they could raise the capital from investors.  But they don't have that, so they still don't have a way to finance the development costs.  Since the development costs are in the billions for crew Dream Chaser (going by their CCtCap proposal), they'd need to demonstrate an awfully big market for commercial crew and show that they could capture a significant portion of it with a high profit margin for the numbers to be interesting to investors.  They're at a huge disadvantage here because SpaceX and Boeing are having their development costs paid for by CCtCap.  So, even if a large commercial crew market could be shown to exists, Dream Chaser would be competing in it with two other competitors whose prices wouldn't have to cover development costs while their own prices would.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Nindalf on 10/01/2014 08:04 pm
Starting from the reusable aircraft and the reusable spacecraft, with no launch pad needed, they could evolve forward with a liquid-fuelled first stage to replace the two solid-fuel stages, then one that lands on a runway (the solid version already has wings), and then a reusable upper or integrated upper/spacecraft.  They have margin to work with to add reusability since the solid-fuel stages are mass-inefficient.

Reusable doesn't mean that it's economical. You still have to amortize your development cost on a one-off (or small series) vehicle. A low flight rate makes it a hangar queen, which is losing money. Reusability only makes sense if it's scaled to meet demand.

So what demand is there for a 3-person orbital taxi outside of CCtDev or for 3-person suborbital point-to-point flights?
Space tourism.  Low-budget space programs.  They can do a cargo version.

I think that even without rocket reusability (as long as they get a more economical upper stage engine -- as I understand it, the RL-10 is only a baseline), they can aim for under $25 million per seat and the most comfortable ride to and from orbit.

With that taper on it, the upper stage even looks the right shape for a capsule with a bit of lift, if there's a heat shield hidden in that interstage.  They could also do repackable solids.  It could be intended to be reusable from the get-go.

This is a powerful rocket.  The LEO payload capacity for the Stratolaunch system is equivalent to that of the Falcon 9.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: ChrisWilson68 on 10/01/2014 08:05 pm
If they commit to this version you can most assuredly say goodbye to the current version on Atlas. SNC does not have the money to develop both lines.

They don't have the money to develop either line.

If they commit to this version you can most assuredly say goodbye to the current version on Atlas. SNC does not have the money to develop both lines.

Not necessarily.  The NASA money from the CCtCap award would likely fund the majority of the development work for Dream Chaser,

Assuming they win their CCtCap challenge, which is a big if.  Historically, very few challenges to contract awards win.

whereas I would imagine Sierra Nevada is funding 100% of their part of the "Global Project" (i.e. 75% sized Dream Chaser).

The Global Project and 75% Dream Chaser were two different announcements.  It's not clear whether Global Project is aimed at full sized Dream Chaser or 75% Dream Chaser.  Probably they'll take whatever they can get someone to pay for.

In any event Sierra Nevada isn't funding Global Project.  The whole point of Global Project is to try to find someone else to pay for it.  Since they couldn't get NASA to pay, they're now looking all over the globe for someone to pay.

However I would not be surprised if SNC has considered flying Dream Chaser on a SpaceX vehicle, and I would not be surprised if SpaceX were open to that.  But that likely won't happen without SNC winning a CCtCap award...

I agree with you on that.

Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: ChrisWilson68 on 10/01/2014 08:13 pm
Starting from the reusable aircraft and the reusable spacecraft, with no launch pad needed, they could evolve forward with a liquid-fuelled first stage to replace the two solid-fuel stages, then one that lands on a runway (the solid version already has wings), and then a reusable upper or integrated upper/spacecraft.  They have margin to work with to add reusability since the solid-fuel stages are mass-inefficient.

Reusable doesn't mean that it's economical. You still have to amortize your development cost on a one-off (or small series) vehicle. A low flight rate makes it a hangar queen, which is losing money. Reusability only makes sense if it's scaled to meet demand.

So what demand is there for a 3-person orbital taxi outside of CCtDev or for 3-person suborbital point-to-point flights?
Space tourism.  Low-budget space programs.  They can do a cargo version.

I think that even without rocket reusability (as long as they get a more economical upper stage engine -- as I understand it, the RL-10 is only a baseline), they can aim for under $25 million per seat and the most comfortable ride to and from orbit.

Their CCtCap bid was $3 billion.  They'd need more than 100 people to pay $25 million each just to cover the development cost, even if their ongoing costs were zero.  There's no such demonstrated market.

This is a powerful rocket.  The LEO payload capacity for the Stratolaunch system is equivalent to that of the Falcon 9.

The stratolauch target for payload to LEO is 6,100 kg.  Falcon 9's advertized payload to LEO (with first stage reuse) is 13,150 kg -- more than twice as much.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: arachnitect on 10/01/2014 08:18 pm
This is a powerful rocket.  The LEO payload capacity for the Stratolaunch system is equivalent to that of the Falcon 9.

9v1.1 should have twice the capacity of stratolaunch
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Nindalf on 10/01/2014 08:22 pm
Ah... I saw 13,500 lb and thought it was kg.  That was dumb.

Well, all the more reason it has potential to be cheaper per flight.

edit: There's no reason to believe that the CctCap bid is the amount they'll need to develop this thing.  The CctCap bid included up to 6 operational flights of a spacecraft 2.5 times as big, up to 1200 days lifeboat service, 7 or 8 man-rated Atlas V launches, and dealing with NASA every step of the way.

When they got downselected, I posted that they belonged on a cheaper launch platform.  They seem to have found one.

And they don't have to amortize their development costs in the lifetime of this one vehicle.  They have to amortize their costs over the lifetime of the business.  Recovery of investments can happen after another generation or two of vehicles.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: ChrisWilson68 on 10/01/2014 08:23 pm
But this still makes no sense to me. But then again neither does Stratolaunch. :)

A mini DC (I guess they chuck out all their DC hardware), but you still need a massive aircraft plus 3 expendable stages to get to orbit. In what universe does this look economical?

I agree with you, Stratolaunch has never really made sense.

I think this is SNC's reaction to just being at a huge disadvantage to SpaceX in terms of launch vehicle costs.  Unless they win their CCtCap protest, any conceivable future for crew Dream Chaser is going to have to compete against Dragon.  How can they do that?  There just aren't a lot of launch vehicle choices.  Atlas V is much more expensive.  Other launch vehicles would be hard to get human rated.  So SNC is desperately looking for something to change that.  Stratolaunch is a sign of that desperation.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: butters on 10/01/2014 09:31 pm
dual RL-10 upper stage + 1 small AR solid + booster with bargain-priced Russian engine = quite expensive launch vehicle

dual RL-10 upper stage + 2 large ATK solids (one winged) + reusable plane with longest wingspan ever = cheaper than F9?

Hm...
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Rocket Science on 10/01/2014 10:12 pm
But this still makes no sense to me. But then again neither does Stratolaunch. :)

A mini DC (I guess they chuck out all their DC hardware), but you still need a massive aircraft plus 3 expendable stages to get to orbit. In what universe does this look economical?

I agree with you, Stratolaunch has never really made sense.

I think this is SNC's reaction to just being at a huge disadvantage to SpaceX in terms of launch vehicle costs.  Unless they win their CCtCap protest, any conceivable future for crew Dream Chaser is going to have to compete against Dragon.  How can they do that?  There just aren't a lot of launch vehicle choices.  Atlas V is much more expensive.  Other launch vehicles would be hard to get human rated.  So SNC is desperately looking for something to change that.  Stratolaunch is a sign of that desperation.
Or they are trying to create a market... I don't consider these folks to be a bunch of clowns... We'll just have to wait and see...
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Chris Bergin on 10/01/2014 10:14 pm
Here's my article, using some of the good L2 info we had, with the media releases and a bit more L2 info.

http://www.nasaspaceflight.com/2014/10/dream-chaser-eyes-rides-with-under-review-stratolaunch-system/
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Rocket Science on 10/01/2014 10:22 pm
That was a great read Chris! :)
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: ChrisWilson68 on 10/01/2014 10:29 pm
But this still makes no sense to me. But then again neither does Stratolaunch. :)

A mini DC (I guess they chuck out all their DC hardware), but you still need a massive aircraft plus 3 expendable stages to get to orbit. In what universe does this look economical?

I agree with you, Stratolaunch has never really made sense.

I think this is SNC's reaction to just being at a huge disadvantage to SpaceX in terms of launch vehicle costs.  Unless they win their CCtCap protest, any conceivable future for crew Dream Chaser is going to have to compete against Dragon.  How can they do that?  There just aren't a lot of launch vehicle choices.  Atlas V is much more expensive.  Other launch vehicles would be hard to get human rated.  So SNC is desperately looking for something to change that.  Stratolaunch is a sign of that desperation.
Or they are trying to create a market... I don't consider these folks to be a bunch of clowns... We'll just have to wait and see...

Who said they're a bunch of clowns?  You're reading into it something that is very different from what I'm saying.

SNC has been working on Dream Chaser in hopes of winning NASA's CCtCap competition.  They knew they might lose, but it was worth the risk.  The fact that they lost doesn't mean they were a bunch of clowns.  They just took a risk and lost, that's all.  It's just what you'd expect from people willing to take risks.

Now, they're desperate to find something to save the project.  No surprise there.  So they're trying to find anything they can to save it, no matter how long the odds are.  They have nothing to lose since they're dead otherwise.  No clowns involved, just perfectly reasonable people reacting to a situation.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Rocket Science on 10/01/2014 10:41 pm
But this still makes no sense to me. But then again neither does Stratolaunch. :)

A mini DC (I guess they chuck out all their DC hardware), but you still need a massive aircraft plus 3 expendable stages to get to orbit. In what universe does this look economical?

I agree with you, Stratolaunch has never really made sense.

I think this is SNC's reaction to just being at a huge disadvantage to SpaceX in terms of launch vehicle costs.  Unless they win their CCtCap protest, any conceivable future for crew Dream Chaser is going to have to compete against Dragon.  How can they do that?  There just aren't a lot of launch vehicle choices.  Atlas V is much more expensive.  Other launch vehicles would be hard to get human rated.  So SNC is desperately looking for something to change that.  Stratolaunch is a sign of that desperation.
Or they are trying to create a market... I don't consider these folks to be a bunch of clowns... We'll just have to wait and see...

Who said they're a bunch of clowns?  You're reading into it something that is very different from what I'm saying.

SNC has been working on Dream Chaser in hopes of winning NASA's CCtCap competition.  They knew they might lose, but it was worth the risk.  The fact that they lost doesn't mean they were a bunch of clowns.  They just took a risk and lost, that's all.  It's just what you'd expect from people willing to take risks.

Now, they're desperate to find something to save the project.  No surprise there.  So they're trying to find anything they can to save it, no matter how long the odds are.  They have nothing to lose since they're dead otherwise.  No clowns involved, just perfectly reasonable people reacting to a situation.
Ok Chris, maybe it’s your use of the word “desperate”. We don’t know what SNC’s plan B was/is or how long Mark and Paul have been discussing this proposal...
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: ChrisWilson68 on 10/01/2014 11:05 pm
Ok Chris, maybe it’s your use of the word “desperate”. We don’t know what SNC’s plan B was/is or how long Mark and Paul have been discussing this proposal...

I don't mean desperate as a put down of the people involved.  If I was faced with having to fire my whole team and mothball everything they and I had been working very hard on and believed in, I would be desperate too.  I'd grasp at every straw to try to save it.

There's a phenomenon I see all the time in Silicon Valley where two start-up companies, neither of which has a customer, make a big announcement about how they're going to work together.  The announcement makes it sound like each company has found a great new opportunity and they're really excited to be working together.  But, really, they still need to find a customer.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Mike Harris-Stone on 10/02/2014 03:37 am

Their CCtCap bid was $3 billion.  They'd need more than 100 people to pay $25 million each just to cover the development cost, even if their ongoing costs were zero.  There's no such demonstrated market.


I think you're making a mistake here.  The 3 billion bid would have included operational costs as well as development costs and of course profit as well.  The cost for just bare bones development is probably much lower. 

My guess that SNC is equipped to handle it is based on their behavior.  While Boeing has treated Commercial Crew as strictly a Govt. project and SpaceX has treated it as a milestone on their way to Mars, SNC has consistently been pursing it in view of a commercial market beyond NASA with their international alliances and now Global Project.  (They may be on to something here.  Just as Spacex has opened up Satellite launches to operators who previously could not afford it, SNC may be able to do the same for manned spaceflight.)  What we are seeing is the result of a long prepared strategy -- not a quick, pull it out of your rear reaction to the down select.  IMHO, since they are private and already very profitable, they must be somewhat ready to go all the way IF they have a market.  That's the big question.  How will the market respond? 

If they had won the NASA contract, the way ahead would be much simpler.  With NASA as the tent pole customer, they'd have had a lot more flexibility and time in building out the commercial market.  Now, not having that, it is more stark, but I think covering development cost is not the biggest issue.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: ChrisWilson68 on 10/02/2014 04:13 am

Their CCtCap bid was $3 billion.  They'd need more than 100 people to pay $25 million each just to cover the development cost, even if their ongoing costs were zero.  There's no such demonstrated market.

I think you're making a mistake here.  The 3 billion bid would have included operational costs as well as development costs and of course profit as well.  The cost for just bare bones development is probably much lower.

Their CCtCap bid was for a combination of the development contract at 6 flights.  To fly their first hundred people, they'll have to do well over 6 flights, so there's no way they can fly 100 people for less than their CCtCap bid.

My guess that SNC is equipped to handle it is based on their behavior.

Their behavior is that they immediately laid off a bunch of staff upon hearing the CCtCap decision, in spite of the fact that they still have CCiCap milestones left to complete.  That does not suggest a company that is capable of self-financing Dream Chaser.

While Boeing has treated Commercial Crew as strictly a Govt. project and SpaceX has treated it as a milestone on their way to Mars, SNC has consistently been pursing it in view of a commercial market beyond NASA with their international alliances and now Global Project.

Completely untrue.  Both Boeing and SpaceX have been vocal about pursuing every available commercial market.  For years Boeing and Bigelow have been talking about using CST-100 for access to Bigelow stations.

(They may be on to something here.  Just as Spacex has opened up Satellite launches to operators who previously could not afford it, SNC may be able to do the same for manned spaceflight.)  What we are seeing is the result of a long prepared strategy -- not a quick, pull it out of your rear reaction to the down select.  IMHO, since they are private and already very profitable, they must be somewhat ready to go all the way IF they have a market.  That's the big question.  How will the market respond? 

Boeing, SpaceX, and SNC have been aggressively pursuing this market for years.  So far, NASA is the only customer.

If they had won the NASA contract, the way ahead would be much simpler.  With NASA as the tent pole customer, they'd have had a lot more flexibility and time in building out the commercial market.  Now, not having that, it is more stark, but I think covering development cost is not the biggest issue.

Sierra Nevada has around 3,000 employees.  Self-funding a $3 billion development program would be $1 million per employee.  That's a huge obstacle.  There's no way SNC could do it without outside funding.  No investor is going to give that to them without a demonstrated market.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Rocket Science on 10/02/2014 04:49 am
Any individual that can take a design past power point and CGI to an atmospheric test vehicle has earned and deserves to be respected. NASA itself can’t accomplish that for the last couple of decades...If SNC can secure financing and investors; the vehicle will fly and create a market through smaller nations wanting an astronaut among its citizens, orbital tourism or flown experiments without needing the onerous NASA protocols... Even ISS may only live to 2024 at most so far as a destination so one must look beyond it...
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: SwissCheese on 10/02/2014 10:00 am
Would a resized DreamChaser fit inside Ariane 5 (or 6) fairing?

(I know that the probability of ever seeing a manned European (non-Russian) rocket is quite low... but we can always dream :) )
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Jim on 10/02/2014 10:46 am
  Just as Spacex has opened up Satellite launches to operators who previously could not afford it,

They have done no such thing.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Jim on 10/02/2014 10:48 am
the vehicle will fly and create a market through smaller nations wanting an astronaut among its citizens,

That is not a given. 
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Rocket Science on 10/02/2014 11:18 am
the vehicle will fly and create a market through smaller nations wanting an astronaut among its citizens,

That is not a given.
Absolutely true Jim... but within the possible...
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Rocket Science on 10/02/2014 01:15 pm
Would a resized DreamChaser fit inside Ariane 5 (or 6) fairing?

(I know that the probability of ever seeing a manned European (non-Russian) rocket is quite low... but we can always dream :) )
75% DC wingspan approx 5.25m so under a 6m fairing...
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Nibb31 on 10/02/2014 01:58 pm
Why put it inside a fairing? Wouldn't that cause a few more headaches for abort modes?
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Rocket Science on 10/02/2014 02:05 pm
Why put it inside a fairing? Wouldn't that cause a few more headaches for abort modes?
Yes, but it would simplify aerdynamics and and avionics. Time to fire up the wind tunnel and see! :)
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: R7 on 10/02/2014 06:29 pm
the vehicle will fly and create a market through smaller nations wanting an astronaut among its citizens,
That is not a given.
Absolutely true Jim... but within the possible...

option A: two private spacecrafts being developed with NASA funding for existing LVs.
option B: a private spacecraft without NASA funding for LV which does not exist yet (and is not guaranteed to ever do so)

If you'd be one of those smaller nations tell me why on earth would you choose option B instead of waiting option A to come to fruition. B is bound to cost more for potential customer because they'd have to pay to finish the R&D.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Rocket Science on 10/02/2014 08:11 pm
the vehicle will fly and create a market through smaller nations wanting an astronaut among its citizens,
That is not a given.
Absolutely true Jim... but within the possible...
option A: two private spacecrafts being developed with NASA funding for existing LVs.
option B: a private spacecraft without NASA funding for LV which does not exist yet (and is not guaranteed to ever do so)

If you'd be one of those smaller nations tell me why on earth would you choose option B instead of waiting option A to come to fruition. B is bound to cost more for potential customer because they'd have to pay to finish the R&D.
Maybe they don't got the bucks right now... ;D
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Mike Harris-Stone on 10/02/2014 09:25 pm

option A: two private spacecrafts being developed with NASA funding for existing LVs.
option B: a private spacecraft without NASA funding for LV which does not exist yet (and is not guaranteed to ever do so)

If you'd be one of those smaller nations tell me why on earth would you choose option B instead of waiting option A to come to fruition. B is bound to cost more for potential customer because they'd have to pay to finish the R&D.

SNC has a test flight booked for DC on an Atlas V.  The last time I looked, the Atlas V exists.  The whole 75% DC with Stratolaunch is a spin off product, not a replacement for the regular DC.   From SNC's press release the press release re: Global Project

Quote
“The SNC Global Project provides, for the first time in history, an unprecedented and unique set of spaceflight opportunities for clients around the world,” said John Roth, vice president of business development for SNC’s Space Systems. “SNC is offering access to crewed or uncrewed space missions that include an optionally-piloted space vehicle, a launch vehicle or choice of launch vehicles, and the supporting infrastructure and systems required for such a valuable program.
  (Emphasis mine)

This isn't just about Stratolaunch.

Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Mike Harris-Stone on 10/02/2014 09:28 pm
If they commit to this version you can most assuredly say goodbye to the current version on Atlas. SNC does not have the money to develop both lines.

That's NOT what SNC says.  See their Global Launch press release:

http://www.sncspace.com/press_more_info.php?id=411
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: veblen on 10/02/2014 09:30 pm
What a relief I get tired of the "only the cheapest s/c is worthwhile" arguments over and over again.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: JasonAW3 on 10/02/2014 09:34 pm
the vehicle will fly and create a market through smaller nations wanting an astronaut among its citizens,
That is not a given.
Absolutely true Jim... but within the possible...
Maybe they don't got the bucks right now... ;D

option A: two private spacecrafts being developed with NASA funding for existing LVs.
option B: a private spacecraft without NASA funding for LV which does not exist yet (and is not guaranteed to ever do so)

If you'd be one of those smaller nations tell me why on earth would you choose option B instead of waiting option A to come to fruition. B is bound to cost more for potential customer because they'd have to pay to finish the R&D.

I'm not so certain here.  SNC has a number of other contracts that can keep it going no matter what, and they's got just too much tied up in the Dream Cjaser NOT to see it completed and fully tested.

There've been a couple of companies that were developing something under Government Contract and had the contract yanked out from under them.  Many times, by the time it happened, the project was pretty near completion, so they said WTF? and completed the project anyway.  Some of our best combat aircraft came about that way.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Mike Harris-Stone on 10/02/2014 09:44 pm

While Boeing has treated Commercial Crew as strictly a Govt. project and SpaceX has treated it as a milestone on their way to Mars, SNC has consistently been pursing it in view of a commercial market beyond NASA with their international alliances and now Global Project.

Completely untrue.  Both Boeing and SpaceX have been vocal about pursuing every available commercial market.  For years Boeing and Bigelow have been talking about using CST-100 for access to Bigelow stations.


My point is that SNC has put a product on offer at a conference and has agreements formed with at least two other space agencies.  It's concrete in the sense that they have an actual business unit you can deal with if you wanted to take them up on it.  Boeing has stated that they don't see a market beyond the station yet and, for the moment, hasn't put effort into a similar initiative as far as I'm aware. 

Didn't Spacex offer Dragon Cargo as a kind of flying space lab?  They will probably do more with Dragon V2 in the future.

But for now I think SNC is ahead of the pack.  It's too bad they weren't selected though because that would have put these offerings of theirs in an entirely different light -- knowing that the vehicle will go ahead.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Rocket Science on 10/02/2014 10:14 pm

While Boeing has treated Commercial Crew as strictly a Govt. project and SpaceX has treated it as a milestone on their way to Mars, SNC has consistently been pursing it in view of a commercial market beyond NASA with their international alliances and now Global Project.

Completely untrue.  Both Boeing and SpaceX have been vocal about pursuing every available commercial market.  For years Boeing and Bigelow have been talking about using CST-100 for access to Bigelow stations.


My point is that SNC has put a product on offer at a conference and has agreements formed with at least two other space agencies.  It's concrete in the sense that they have an actual business unit you can deal with if you wanted to take them up on it.  Boeing has stated that they don't see a market beyond the station yet and, for the moment, hasn't put effort into a similar initiative as far as I'm aware. 

Didn't Spacex offer Dragon Cargo as a kind of flying space lab?  They will probably do more with Dragon V2 in the future.

But for now I think SNC is ahead of the pack.  It's too bad they weren't selected though because that would have put these offerings of theirs in an entirely different light -- knowing that the vehicle will go ahead.
Boeing "show me the money"... ;D
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Jim on 10/02/2014 11:49 pm

1.  My point is that SNC has put a product on offer at a conference and has agreements formed with at least two other space agencies.  It's concrete in the sense that they have an actual business unit you can deal with if you wanted to take them up on it.  Boeing has stated that they don't see a market beyond the station yet and, for the moment, hasn't put effort into a similar initiative as far as I'm aware. 

snip

2.  But for now I think SNC is ahead of the pack.  It's too bad they weren't selected though because that would have put these offerings of theirs in an entirely different light -- knowing that the vehicle will go ahead.

1.  It isn't concrete, it is dust.  Agreements with no money exchanged are meaningless.  Having a business unit means it is real?  It means nothing.  There have been many business units without hardware.

2.  Huh?  They are a distance 3rd.  There is nothing that says either vehicle is going ahead.   They have no "offerings".  Again, interest without money is meaningless.

A little more research needs to be done here because reality is different than what is posted here.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Rocket Science on 10/03/2014 12:54 am
I was just thinking if DC will have/had a dorsal hatch as was planned for the X-38 it could use it's downward firing thrusters for station reboost...Hmmm...
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: bubbagret on 10/03/2014 03:51 am
I was just thinking if DC will have/had a dorsal hatch as was planned for the X-38 it could use it's downward firing thrusters for station reboost...Hmmm...

What would prevent them from using the forward firing thrusters with the aft hatch as designed?
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Mike Harris-Stone on 10/03/2014 04:07 am

1.  My point is that SNC has put a product on offer at a conference and has agreements formed with at least two other space agencies.  It's concrete in the sense that they have an actual business unit you can deal with if you wanted to take them up on it.  Boeing has stated that they don't see a market beyond the station yet and, for the moment, hasn't put effort into a similar initiative as far as I'm aware. 

snip

2.  But for now I think SNC is ahead of the pack.  It's too bad they weren't selected though because that would have put these offerings of theirs in an entirely different light -- knowing that the vehicle will go ahead.

1.  It isn't concrete, it is dust.  Agreements with no money exchanged are meaningless.  Having a business unit means it is real?  It means nothing.  There have been many business units without hardware.

2.  Huh?  They are a distance 3rd.  There is nothing that says either vehicle is going ahead.   They have no "offerings".  Again, interest without money is meaningless.

A little more research needs to be done here because reality is different than what is posted here.

By your standards, when Boeing sold their first 787's, they didn't have any offerings either since they had no actual airplanes yet.  But customers ordered 787's.  Why, because they had confidence that Boeing would deliver, which it has -- albeit quite later than originally planned.  My point with SNC is that they have put something together and are putting it out there.  Will buyers have enough confidence to come forward?  Really your guess and my guess are just guesses.  Boeing, as far as I know, as done nothing comparable with CST-100.  Could they have done the same thing as SNC?  Of course  -- but they won't unless they are sure there is a market first.  Spacex has not done the same thing either.  That's why I say SNC is ahead...not necessarily in building a vehicle, although they are pretty far along having already "bent metal" on their first orbital vehicle...but as a business trying to commercialize manned space flight...they are out there in the lead.  Some might say they are too far out there in the lead.  My other point is they just didn't invent their Global Launch in a week.  It was prepared beforehand.  If they had won the competition...then it would have a much more serious tone to it, since everyone would know that yes....there really will be a Dreamchaser.

There is a lot that says SNC is going ahead.  You seem to think they are some kind of start up.  Not true.  (Private owned company with a couple billion a year in sales and an excellent track record of profitability, lots of investment already put in and years of development going back to before Commercial crew.  They don't seem to be giving up as easily as some of you think they should.   :-*)  You can assert that DC is dead all you want.  But you don't know what's going to happen any more than I do. 

The one thing we do agree on is that having customers is critical.  The days ahead should be interesting.

In the end we will all see what happens and who launches first:  Boeing or SNC. 

I know who I'm rooting for.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: R7 on 10/03/2014 06:31 am
This isn't just about Stratolaunch.

Err .. so you expect the smaller nations to fund the full size DC + Atlas V config and miniDC + Strato instead of waiting for rides on spacecrafts developed with NASA funds??

Where are these die hard libertarian smaller nations bitten by space bug?

Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Lars-J on 10/03/2014 06:40 am

1.  My point is that SNC has put a product on offer at a conference and has agreements formed with at least two other space agencies.  It's concrete in the sense that they have an actual business unit you can deal with if you wanted to take them up on it.  Boeing has stated that they don't see a market beyond the station yet and, for the moment, hasn't put effort into a similar initiative as far as I'm aware. 

snip

2.  But for now I think SNC is ahead of the pack.  It's too bad they weren't selected though because that would have put these offerings of theirs in an entirely different light -- knowing that the vehicle will go ahead.

1.  It isn't concrete, it is dust.  Agreements with no money exchanged are meaningless.  Having a business unit means it is real?  It means nothing.  There have been many business units without hardware.

2.  Huh?  They are a distance 3rd.  There is nothing that says either vehicle is going ahead.   They have no "offerings".  Again, interest without money is meaningless.

A little more research needs to be done here because reality is different than what is posted here.

By your standards, when Boeing sold their first 787's, they didn't have any offerings either since they had no actual airplanes yet.  But customers ordered 787's.  Why, because they had confidence that Boeing would deliver, which it has -- albeit quite later than originally planned.  My point with SNC is that they have put something together and are putting it out there.  Will buyers have enough confidence to come forward?

The distinction you are missing is that for the 787 orders, money was exchanged. Down payments were made. That's what you do when you sign an order.

Which is very different than this DC-Stratolauncher business (so far).
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Nibb31 on 10/03/2014 07:06 am
I don't know what the agreement with JAXA was, but ESA only agreed to contribute their implementation of the IDS, probably in exchange for a seat or two to the ISS.

No foreign agency has agreed to fund the development of DreamChaser. The whole point of a government agency is to fund domestic research and development. If ESA wanted access to the ISS, they wouldn't subsidize a US company to do it. They would offer a barter arrangement with NASA that provides work for a European company.

Foreign countries are not going to pay for the R&D of a US company.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: woods170 on 10/03/2014 07:17 am
I don't know what the agreement with JAXA was, but ESA only agreed to contribute their implementation of the IDS, probably in exchange for a seat or two to the ISS.

No foreign agency has agreed to fund the development of DreamChaser. The whole point of a government agency is to fund domestic research and development. If ESA wanted access to the ISS, they wouldn't subsidize a US company to do it. They would offer a barter arrangement with NASA that provides work for a European company.

Foreign countries are not going to pay for the R&D of a US company.
Correct. The agreements between SNC and foreign space agencies is for exchange of goods/services and knowledge. In other words: bartering.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Rocket Science on 10/03/2014 09:22 am
I was just thinking if DC will have/had a dorsal hatch as was planned for the X-38 it could use it's downward firing thrusters for station reboost...Hmmm...

What would prevent them from using the forward firing thrusters with the aft hatch as designed?
So far only CST-100 is able to offer station reboost. It's a bit of a bonus if it is able to... I have no specs on DC forward RCS and AFAIK it has been never mentioned from SNC... Shuttle used downward firing thrusters...
A 75% scale DC MKII "may" be too small to use rear tunnel, I'm not certain dimensionally at this point and they may need that area for tanks etc... I guess we’ll have to see what they come up with..
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: dror on 10/03/2014 01:02 pm
Hello all, this is my first post, after about 4 years voyeuring NSF forums ;-)

SNC announcement is really intriguing. I agree with Chris Wilson about the funding issue but, forgetting it for a while, I think that the scaled down version of DC may have the following characteristic:
- exactly the same dimensions and body (modifying it, means redesigning the whole thing from scratch: too expensive and time consuming)
- switch to the new liquid propulsion
- moving the docking hatch above the cabin (the only external modification)
- utilize half of the internal space (the rear half) to add more fuel/oxidizer tanks.
With more fuel, DC will act as the last stage of the launch vehicle (think about the OMS of the Space Shuttle) thus allowing Stratolaunch to carry more than 6t to orbit (but loosing DC internal space and reducing the seats to 3).
I've made no calculations on this, therefore I cannot be sure that it will work, but many of you are strong on this. So, if you want to check it numerically...
Ciao (this forum is awesome!)
From the first time I heard of dream chaser I was wandering if it was possible to design it to include the seconed stage as part of the ship, for reusability resons. Not as big as a shutle orbiter, but not only as a third stage. That could have saved a lot of money per launch.
The reduced performance by the extra heat shields may even out by canceling the hybrid engines with their lesser Isp.
The rear docking port will be moved to the roof entrance.
Could this work?
I guess not, but I would love to hear why not.

You could, but you would have to redesign the entire spacecraft. You would need new engines, since the Centaur's engines are not reusable and the DC's engines don't have the delta V required to reach orbit. You would need new avionics. It would be a lot heavier with a different center of gravity and center of lift - it might not even fly. You would have to redevelop a launch vehicle too - that would no longer be an Atlas V.

It would no longer be a Dream Chaser. You're actually describing something like the Space Shuttle or Buran but without a cargo bay or cross-range capacity. It's not clear how much cheaper that would be. IANARS, but I don't think it would be feasible.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Jim on 10/03/2014 04:35 pm

1.  By your standards, when Boeing sold their first 787's, they didn't have any offerings either since they had no actual airplanes yet.  But customers ordered 787's.

2. .  Will buyers have enough confidence to come forward? 

3. Boeing, as far as I know, as done nothing comparable with CST-100.

4.  There is a lot that says SNC is going ahead. 

5.  You seem to think they are some kind of start up. 

6.   You can assert that DC is dead all you want.  But you don't know what's going to happen any more than I do. 



Wrong on all takes.

1. Keyword is sold.  Money was exchanged.  SNC hasn't sold anything nor has anybody ordered anything.  SNC just threw a concept out there.

2.  No they won't, because they haven't come out for more real projects such as Bigelow or SpaceX  or Soyuz.

2.  Quite wrong.  Bigelow has worked with Boeing for the same market. 

4.   It is only marketing and spin out there.  No real data to support your claim

5. .  they are when is comes to major spacecraft

6. .  Quite the opposite.  I have some insight, where as you have none.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: WM68 on 10/03/2014 05:37 pm

... 



... SpaceX  ...


Jim, I think you made an error there and spelled SpaceX correctly...  ;)
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Mike Harris-Stone on 10/04/2014 01:24 am
This isn't just about Stratolaunch.

Err .. so you expect the smaller nations to fund the full size DC + Atlas V config and miniDC + Strato instead of waiting for rides on spacecrafts developed with NASA funds??

Where are these die hard libertarian smaller nations bitten by space bug?

Read the press releases....

If I'm reading correctly, MiniDC would be a funded by Stratolaunch.  They fund the hardware from SNC and then turn around and resell it as a service -- manned spaceflight.  SNC doesn't need to put up all the capital for this and wouldn't.

If you want to buy manned access to space right now and you aren't NASA who has a PRODUCT on the market?

Russia will sell you a seat on a Soyuz.
SNC is now offering their turnkey program called Global Launch utilizing the Dreamchaser (which is in development to state the obvious) and a variety of launch vehicle options.  Coming from their own news release

The fact that the product isn't fully developed, but is still being sold isn't that unusual.  Spacex is both selling and has on contract Falcon Heavy launches even though the vehicle is still under development.

Sure cash hasn't changed hands.  That's pretty bloody obvious isn't it?  But since a product is being offered, cash could change hands and may.  We will have to wait and see.

Selling a product is very different from trying to get someone to "fund your RD".  If someone buys the product, then SNC is on the hook to deliver it.  Yea, that helps pay for RD and operations etc. but if things work out, it also ends up providing profit as well.   This is how business works folks.

Boeing and SpaceX have agreements with Bigelow.  But as far as I know, if you want to contract with Boeing or SpaceX for a manned flight on their vehicle today...I'm not sure if you could.  Though doubtless you could approach them.  Boeing has talked about having tourist seats on flights CST-100, but I don't think they've created a phone number or business unit you could approach about that yet.

My only point is this SNC has done this....created a business unit and put a product...Global Spaceflight out for sale.  In the sense of business, as far as I know they are the first to ever actually offer something like this.

Is anyone knows of someone else who has...please let me know.

As for funding development...they are a pretty good size firm actually and seem to be able to get pretty far along on their own dime.  How far they can go, only they know.  But here they are actually in fact trying to sell a product and not "raise money."  As I've mentioned before, having customers to use your product is the big deal in business.  It's called demand.  If you've got demand, you can fund development.  Is there demand for turnkey space operations?  The answer to that...I don't know. (and neither do you...though we can both guess if we want.)  But we will see.


Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Mike Harris-Stone on 10/04/2014 01:29 am

1.  My point is that SNC has put a product on offer at a conference and has agreements formed with at least two other space agencies.  It's concrete in the sense that they have an actual business unit you can deal with if you wanted to take them up on it.  Boeing has stated that they don't see a market beyond the station yet and, for the moment, hasn't put effort into a similar initiative as far as I'm aware. 

snip

2.  But for now I think SNC is ahead of the pack.  It's too bad they weren't selected though because that would have put these offerings of theirs in an entirely different light -- knowing that the vehicle will go ahead.

1.  It isn't concrete, it is dust.  Agreements with no money exchanged are meaningless.  Having a business unit means it is real?  It means nothing.  There have been many business units without hardware.

2.  Huh?  They are a distance 3rd.  There is nothing that says either vehicle is going ahead.   They have no "offerings".  Again, interest without money is meaningless.

A little more research needs to be done here because reality is different than what is posted here.

By your standards, when Boeing sold their first 787's, they didn't have any offerings either since they had no actual airplanes yet.  But customers ordered 787's.  Why, because they had confidence that Boeing would deliver, which it has -- albeit quite later than originally planned.  My point with SNC is that they have put something together and are putting it out there.  Will buyers have enough confidence to come forward?

The distinction you are missing is that for the 787 orders, money was exchanged. Down payments were made. That's what you do when you sign an order.

Which is very different than this DC-Stratolauncher business (so far).

Agreed.  That is pretty obvious, isn't it?  And no, I'm not missing the distinction.  My point is that no one can place orders until there is a product to be ordered.  Right?  Global Launch is in fact such a product.  Like the 787 or the Falcon Heavy, one can order it while it's in development.  (And that is the limit of the 787 analogy.  There is a huge difference in customer confidence between airlines buying 787's from Boeing, who they'd bought from before, and anyone buying turnkey manned spaceflight from SNC.  Absolutely.  My only point is you can sell it before the hardware is ready IF someone wants to buy it and has confidence in your ability to deliver a product.)
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Mike Harris-Stone on 10/04/2014 01:52 am

1.  By your standards, when Boeing sold their first 787's, they didn't have any offerings either since they had no actual airplanes yet.  But customers ordered 787's.

2. .  Will buyers have enough confidence to come forward? 

3. Boeing, as far as I know, as done nothing comparable with CST-100.

4.  There is a lot that says SNC is going ahead. 

5.  You seem to think they are some kind of start up. 

6.   You can assert that DC is dead all you want.  But you don't know what's going to happen any more than I do. 



Wrong on all takes.

1. Keyword is sold.  Money was exchanged.  SNC hasn't sold anything nor has anybody ordered anything.  SNC just threw a concept out there.


SNC has put a product out there.  That is more than a concept, especially when hardware is this far along in development.  Concepts don't have test articles or space hardware built by Lockheed.  This does, albeit it's not finished.  Whether money will be exchanged for this product remains to be seen.  But it's not impossible.



2.  No they won't, because they haven't come out for more real projects such as Bigelow or SpaceX  or Soyuz.



They have come out for Soyuz.  Soyuz has sold some tourist seats. 

Bigelow is more real than SNC????  SNC is a highly successful government contractor with lots of deals happening.  They helped the Navy land drones on Carriers and got an award for it.  They're contracted to build the friggen life support for CLS-100.  And you're telling me that Bigelow is more real than that? 



2.  Quite wrong.  Bigelow has worked with Boeing for the same market. 



Bigelow is offering a turnkey manned spaceflight program where the vehicle lands in your own country?
Since when?  You may disagree, but I think this is a different kind of offering than one Bigelow has.  So I don't think it's really the same market.  A Jeep and a Mini may both be cars, but are they aimed at the same kind of buyer?


4.   It is only marketing and spin out there.  No real data to support your claim



What exactly do you mean by "data" in this context?  A project that has been funded by NASA and covered by every news organization on the planet isn't data? 


5. .  they are when is comes to major spacecraft.



True to a point...but having successfully built space hardware for years would give them a pretty good leg up I'd say.   And what they don't know, they contract out.  Have you forgotten they are partnered with Lockheed and that Lockheed is building the orbital vehicle?  They aren't stupid and they aren't dreamers, in spite of the name of their craft.



6. .  Quite the opposite.  I have some insight, where as you have none.

Is that a fact?  And why put the little personal spin on the end?  Do you think adding an insult bolsters your argument? 

My father knows a lot about spaceplanes and a lot about Dreamchaser.  He was the project manager on HL-20.  He sat with John Young and Robert Crippen while they flew simulated aborts to launch site before the first flight of Columbia and told me about when I was in High School.  I watched the launch of Columbia in 1981 with him and got a very tangible sense of the danger.  I also work in business and know a fair amount about it.  No insight???  I don't know everything but I do know this...no generalization is true (except that one)   :)

Is it possible to have a little friendly disagreement on this forum without resorting to put downs?

Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Kabloona on 10/04/2014 03:26 am
Hi Mike welcome to the forum.

I see you've met Jim. Don't take offense; that's the way he treats all newcomers. And everyone else. So join the crowd. ;)

He works at the Cape and does know a lot. And he doesn't bother to sugarcoat his facts/opinions. But he's a good guy and you'll get used to it once you realize it's not personal.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: R7 on 10/04/2014 11:25 am
If I'm reading correctly, MiniDC would be a funded by Stratolaunch.  They fund the hardware from SNC and then turn around and resell it as a service -- manned spaceflight.  SNC doesn't need to put up all the capital for this and wouldn't.

I don't see that implied in the presser and it's irrelevant, in the end customers would pay it.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Nindalf on 10/04/2014 06:20 pm
If I'm reading correctly, MiniDC would be a funded by Stratolaunch.  They fund the hardware from SNC and then turn around and resell it as a service -- manned spaceflight.  SNC doesn't need to put up all the capital for this and wouldn't.

I don't see that implied in the presser and it's irrelevant, in the end customers would pay it.
It's plausible and relevant.  Stratolaunch is funded by a billionaire enthusiast who has basically been finding competent existing teams and contracting them to do the work.

Roc is a Scaled Composites job, and Thunderbolt is contracted to Orbital ATK, so contracting SNC to build the Drm Chasr (Shrike?  Sparrow?  Spark?  Silver Lining?) would be logical and consistent, and would mean that SNC didn't have to come up with capital from some other source while they were working on it.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: R7 on 10/04/2014 06:56 pm
It's plausible and relevant.  Stratolaunch is funded by a billionaire enthusiast who has basically been finding competent existing teams and contracting them to do the work.

I'm under the impression that as a private company Stratolaunch is supposed to make profit. Will Allen get philanthropic and deal with DC (and perhaps Strato LV too) as sunk cost?
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Nindalf on 10/04/2014 07:43 pm
It's plausible and relevant.  Stratolaunch is funded by a billionaire enthusiast who has basically been finding competent existing teams and contracting them to do the work.

I'm under the impression that as a private company Stratolaunch is supposed to make profit. Will Allen get philanthropic and deal with DC (and perhaps Strato LV too) as sunk cost?
I'm sure he hopes that Stratolaunch will eventually turn a profit, but there are much easier and safer ways to turn money into more money.  Sometimes things come out of the customer's pockets in the end, sometimes they come out of the investor's pocket without providing a return, and sometimes they get paid for with subsidies.  With no crystal ball, you can only say where the money's coming from up front.

The Eagles system and the mini-DC, don't have to turn an immediate operating profit for the whole thing to be profitable.  It's experience, and may lead to another generation that does turn an operating profit.

Even if the whole project takes 30 years to come out in the black, Paul Allen could come out ahead in 10 years by making a show of potential and then going public or selling the whole company.  Perceived potential can be a saleable asset.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: yg1968 on 10/05/2014 03:09 am
This is interesting:

Quote
“What we’re offering is a turnkey capability: Think of it as a ‘space program in a box,’” Cassie Lee, business development manager at SNC, said in a Sept. 30 briefing about the program. Customers could choose to launch Dream Chaser on one of several different launch vehicles, and have the spacecraft land in their home countries, she said.

http://www.spacenews.com/article/civil-space/42079sierra-nevada-reviews-options-for-dream-chaser%E2%80%99s-future
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Mike Harris-Stone on 10/05/2014 03:36 am
It's plausible and relevant.  Stratolaunch is funded by a billionaire enthusiast who has basically been finding competent existing teams and contracting them to do the work.

I'm under the impression that as a private company Stratolaunch is supposed to make profit. Will Allen get philanthropic and deal with DC (and perhaps Strato LV too) as sunk cost?

I've done software design and development for a lot of different companies and each one is unique.  All businesses try to make money, but that often isn't the only motivation -- especially when the business is privately owned.  Where I work now, the owner is really much more about making people's lives better than making a profit.  And since it's privately owned, the owner can do that.  SpaceX seems to be about getting a colony to mars.  Corporations are more constrained and conservative I believe, and more driven by their shareholders to increase their wealth as quickly as possible.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Zed_Noir on 10/05/2014 10:28 am
It's plausible and relevant.  Stratolaunch is funded by a billionaire enthusiast who has basically been finding competent existing teams and contracting them to do the work.

I'm under the impression that as a private company Stratolaunch is supposed to make profit. Will Allen get philanthropic and deal with DC (and perhaps Strato LV too) as sunk cost?

Allen have more than enough money to indulge in any ventures he wants. I see this as getting a footnote in history. Stratolaunch does not need to make a profit, just not loss too much money.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: ChrisWilson68 on 10/08/2014 06:46 am
All this speculation that Paul Allen is going to fund Mini-Dream Chaser is wishful thinking.  If he were going to fund it, the press release would have trumpeted that fact.  The press release was all about trying to give the impression Mini-Dream Chaser on Stratolaunch was definitely going to happen.  If Allen were actually going to finance it, just saying so would be the best possible way to make people believe it was going to happen.

When press releases don't mention where the financing is going to come from, it's because the financing is not yet in place.

Just look at the Inspiration Mars announcement.  They made a huge deal of the fact that Tito was committing to pay the first $100 million, even though that was only a fraction of what they needed to raise.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Rocket Science on 10/10/2014 10:18 am
All this speculation that Paul Allen is going to fund Mini-Dream Chaser is wishful thinking.  If he were going to fund it, the press release would have trumpeted that fact.  The press release was all about trying to give the impression Mini-Dream Chaser on Stratolaunch was definitely going to happen.  If Allen were actually going to finance it, just saying so would be the best possible way to make people believe it was going to happen.

When press releases don't mention where the financing is going to come from, it's because the financing is not yet in place.

Just look at the Inspiration Mars announcement.  They made a huge deal of the fact that Tito was committing to pay the first $100 million, even though that was only a fraction of what they needed to raise.
Inspiration Mars has nothing to do with Dream Chaser in terms of project ambitions, scope or scale and thus is Non sequitur...
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: ChrisWilson68 on 10/10/2014 10:40 am
All this speculation that Paul Allen is going to fund Mini-Dream Chaser is wishful thinking.  If he were going to fund it, the press release would have trumpeted that fact.  The press release was all about trying to give the impression Mini-Dream Chaser on Stratolaunch was definitely going to happen.  If Allen were actually going to finance it, just saying so would be the best possible way to make people believe it was going to happen.

When press releases don't mention where the financing is going to come from, it's because the financing is not yet in place.

Just look at the Inspiration Mars announcement.  They made a huge deal of the fact that Tito was committing to pay the first $100 million, even though that was only a fraction of what they needed to raise.
Inspiration Mars has nothing to do with Dream Chaser in terms of project ambitions, scope or scale and thus is Non sequitur...

No, it isn't a non-sequitor.  It's an example of how when financing has been lined up, press releases tend to trumpet that fact.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Rocket Science on 10/10/2014 11:04 am
All this speculation that Paul Allen is going to fund Mini-Dream Chaser is wishful thinking.  If he were going to fund it, the press release would have trumpeted that fact.  The press release was all about trying to give the impression Mini-Dream Chaser on Stratolaunch was definitely going to happen.  If Allen were actually going to finance it, just saying so would be the best possible way to make people believe it was going to happen.

When press releases don't mention where the financing is going to come from, it's because the financing is not yet in place.

Just look at the Inspiration Mars announcement.  They made a huge deal of the fact that Tito was committing to pay the first $100 million, even though that was only a fraction of what they needed to raise.
Inspiration Mars has nothing to do with Dream Chaser in terms of project ambitions, scope or scale and thus is Non sequitur...

No, it isn't a non-sequitor.  It's an example of how when financing has been lined up, press releases tend to trumpet that fact.
If you equate providing a service to LEO and some flight of fancy around Mars in the same terms without considering the orders of magnitude in technical risk or funding then there is no point discussing with you... Let it play out and stop trying to shut-down all Dream Chaser topic threads... Mods take note...
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: TrevorMonty on 10/11/2014 07:12 pm
Would there be a market for a micro DC. One that can replace the Rocket lab Electron 3 stage and can support a Nano rack payload for few days.
We talking $5m to fly dedicated nano rack size experiment. Customer could fly when they want and don't have to wait weeks to get the result back. A low G reentry is also a plus.

Because it is dedicated to running microgravity experiments, a LEO should be adequate.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: docmordrid on 10/11/2014 09:07 pm
VG/Space Adventures orbital joyrides?
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Prober on 10/12/2014 04:58 pm
A 75% scaled DreamChaser would be useless as a military transport. It could only drop 3 or 4 people, a Mach 20 reentry isn't exactly stealthy and it needs a friendly runway large enough to land a C-5 Galaxy to bring it back (does it even fit inside a C-5 ?)

hmmm a 75% scaled DC might open up more launchers.  Anyone have a rough launch weight?

for military a scaled DC and Cygnus combo in orbit = MOL (with a slightly different mission)
 
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Robotbeat on 10/12/2014 05:09 pm
MOL: totally useless now we have digital spy satellites.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: R7 on 10/12/2014 05:14 pm
Would there be a market for a micro DC. One that can replace the Rocket lab Electron 3 stage and can support a Nano rack payload for few days.

Cease and desist. You are ruining my joke (http://forum.nasaspaceflight.com/index.php?topic=35770.msg1265814#msg1265814).  :D

Would payloads that small have any pressing need for low-g reentry and cross range. Those are human-related selling points.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: yg1968 on 10/14/2014 12:43 am
Why SNC lost:
http://aviationweek.com/space/why-nasa-rejected-sierra-nevadas-commercial-crew-vehicle
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Todd Martin on 10/14/2014 02:51 am
The AV week article is fascinating, showing William Gerstenmaier's thoughts on why he decided it was better for NASA to pay $900 million dollars more for Boeing's CST100 than SNC's DC. 

We know all 3 contenders completed many milestones with literally truck-loads of analysis & documentation, tests, and reviews.  Each of them succeeded in meeting NASA's requirements.  And yet, Gerst wasn't satisfied and chose "better management & technical approach" over cost. 

Looking over his Bio, I don't think he did it for a cushy job at Boeing after leaving public service.  His Engineering credentials are sound.  But, he's 60 years old and has been managing NASA HSF programs for a long time.  He's been at NASA through Challenger & Columbia.  He's seen program after program die (OSP, Venturestar, Constellation) and fail from technical & budget problems.  He commands an army of bureaucrats tasked with reducing risk no matter how slight.  His career has depended on CYA.

The result IMHO is an irrational prejudice against the "Newspace" approach.  A lean team of young engineers putting in long hours to deliver a modern spacecraft is judged unsound despite the reams of technical paperwork his program required while at the same time his massive army of old NASA engineers trudges for 10 years now with a cost 10 times higher and is just now getting around to launching a shell that is over-weight and inferior in dozens of ways.

Congress doesn't need to throw more money at NASA.  Congress needs to re-organize NASA to allow programs to succeed.  Guys like William Gerstenmaier are now the problem, not the solution to manned spaceflight.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Jim on 10/14/2014 03:16 am

1.  The result IMHO is an irrational prejudice against the "Newspace" approach. 

2.  A lean team of young engineers putting in long hours to deliver a modern spacecraft is judged unsound despite the reams of technical paperwork his program required while at the same time his massive army of old NASA engineers

3.  trudges for 10 years now with a cost 10 times higher and is just now getting around to launching a shell that is over-weight and inferior in dozens of ways.

4.  Congress doesn't need to throw more money at NASA.  Congress needs to re-organize NASA to allow programs to succeed.  Guys like William Gerstenmaier are now the problem, not the solution to manned spaceflight.

Your "MHO" has no data to back it up and your conclusions are off base.  And you say "New space" approach as "lean team of young engineers putting in long hours" which is wrong and also doesn't guarantee success.

1.  How does this show a "prejudice" much less an irrational one.  If anything is irrational, it is this posts. 

2.  You don't if SNC can deliver the spacecraft.

3.  Inferior?   talk about prejudiced. You have nothing to support this claim.

4.  You have done nothing to prove your points, except shown your prejudice and you slander the man in the process.

Gerst has been involved with COTS, CRS, NLS II, prior CCP projects, etc. 
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Todd Martin on 10/14/2014 03:30 am
Jim, I pointed out several facts that back up my assertion.  FACT:  William has been administering to NASA's HSF program since 2005.  FACT:  Orion has been the centerpiece of NASA's HSF spacecraft development since 2004.  FACT:  Orion is costing us 10 times more than DC and is further from completion.  Anyone who chooses Orion as having "good management & technical approach" while bashing SNC which does more with 1/10 the cost in less time is wrong for the job.

 

Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Jim on 10/14/2014 03:47 am
1.  FACT:  William has been administering to NASA's HSF program since 2005. 
2. FACT:  Orion has been the centerpiece of NASA's HSF spacecraft development since 2004.
3  FACT:  Orion is costing us 10 times more than DC and is further from completion.  Anyone who chooses Orion as having "good management & technical approach" while bashing SNC which does more with 1/10 the cost in less time is wrong for the job.


"Facts" that in no way support your claims or conclusions, like the many in your previous posts.

1.  Meaningless fact. It doesn't matter when he started
2.  CEV was started in 2005 but MPCV was initiated in 2011
3.  Orion is not one of the choices.  Also, Orion tasks are different than CCP.
4.  DC is not a given.  You don't know if they could complete it.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Mike Harris-Stone on 10/14/2014 04:46 am

Congress doesn't need to throw more money at NASA.  Congress needs to re-organize NASA to allow programs to succeed.  Guys like William Gerstenmaier are now the problem, not the solution to manned spaceflight.

I think you're being a little harsh here.  There are a lot of forces at work which shape our MSF program.  Many of them political and beyond NASA's control.  (And it's Director of HSF)  It's worth remembering that NASA liked SNC and DC, that this was a tough choice and I'm quite sure NASA would like DC continue, they just don't have enough $ to pay for it. 

Orion, like many NASA programs it's been somewhat tossed back and forth a changing mission and changing launch vehicles.  This wasn't entirely NASA's choice or fault.  Lost opportunities have been with NASA since the beginning and are at least partly the result of it being part of a Federal system of government controlled largely by politicians with a strong interest in supporting their local constituencies.  (i.e. Congress). 

Also, with this challenge, NASA is under a kind of attack and has to think about defending itself.  Hence leaked documents, media campaign, etc. 

I'd certainly have preferred seeing DC chosen over Boeing.  And I'd like to know more specifically what the perceived risks associated with DC are.  (This is a design with a very long history.  I see landing a capsule with rocket engines as much more risky and innovative than runway landings with a lifting body.  I'll take a controlled landing with a wide cross range any day of the week over a ballistic landing.  Both of them are old hat now.)

But...so far, in spite of Congressional hostility...Commercial crew and cargo have been a real success story.  As I've posted before, getting Congressional backing for selection of two designs is a real coup.  (We'll see if it continues)  I don't think it's fair to fault WG over this because DC wasn't picked and especially not because of Orion.  (Given a free hand, would what would WG and NASA really do?  Would they have even selected Orion?  NASA has to do what they're told.  It's like the army.  They serve.  They don't direct.  Everyone seems to forget that.)



Congress is incapable of reorganizing NASA on anything but political lines   
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: yg1968 on 10/14/2014 03:28 pm
We'll see when it comes out but the selection statement should indicate how each proposals was evaluated by the selection committee. Gerst has the power to overrule the findings of the selection committee. But if both the selection committee and Gerst say that Boeing's proposal was superior to SNC's, I don't see how SNC can win a challenge. Unfortunately, the AVWeek article doesn't talk about how the proposals were evaluated by the selection committee, they only discuss Gerst's comments.

In any event, I am reserving judgment until I see the actual selection statement. 
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Rocket Science on 10/14/2014 03:55 pm
Having Boeing in CC was essentially like having a “ringer” brought in... CST-100 should have been operational years ago and the CC competition would be for new participants in spaceflight as a replacement, compliment or back-up. The whole concept was flawed from the start...
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Coastal Ron on 10/14/2014 04:11 pm
We'll see when it comes out but the selection statement should indicate how each proposals was evaluated by the selection committee. Gerst has the power to overrule the findings of the selection committee. But if both the selection committee and Gerst say that Boeing's proposal was superior to SNC's, I don't see how SNC can win a challenge. Unfortunately, the AVWeek article doesn't talk about how the proposals were evaluated by the selection committee, they only discuss Gerst's comments.

In any event, I am reserving judgment until I see the actual selection statement.

I too am looking forward to the Selection Statement, but the following except from the Aviation Week article is telling:

"Sierra’s proposal “has more schedule uncertainty. For example, some of the testing planned after the crewed flight could be required before the crewed flight, and the impact of this movement will greatly stress the schedule.”"

To me that means that Sierra Nevada's proposal was deemed as "not qualified" for an award, because they did not have confidence that SNC could be ready by the 2017 date.  If so, then that only left two potential awardees, SpaceX and Boeing.  That is why Boeing was able to "win" while bidding a far higher amount than SNC did.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: yg1968 on 10/14/2014 06:56 pm
We'll see when it comes out but the selection statement should indicate how each proposals was evaluated by the selection committee. Gerst has the power to overrule the findings of the selection committee. But if both the selection committee and Gerst say that Boeing's proposal was superior to SNC's, I don't see how SNC can win a challenge. Unfortunately, the AVWeek article doesn't talk about how the proposals were evaluated by the selection committee, they only discuss Gerst's comments.

In any event, I am reserving judgment until I see the actual selection statement.

I too am looking forward to the Selection Statement, but the following except from the Aviation Week article is telling:

"Sierra’s proposal “has more schedule uncertainty. For example, some of the testing planned after the crewed flight could be required before the crewed flight, and the impact of this movement will greatly stress the schedule.”"

To me that means that Sierra Nevada's proposal was deemed as "not qualified" for an award, because they did not have confidence that SNC could be ready by the 2017 date.  If so, then that only left two potential awardees, SpaceX and Boeing.  That is why Boeing was able to "win" while bidding a far higher amount than SNC did.

Perhaps but you could counter argue that both CCtCap companies don't need to be ready at the same time. Furthermore for $900M more I am sure that SNC could found a way to accelerate those tests...
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Coastal Ron on 10/14/2014 07:45 pm
To me that means that Sierra Nevada's proposal was deemed as "not qualified" for an award, because they did not have confidence that SNC could be ready by the 2017 date.  If so, then that only left two potential awardees, SpaceX and Boeing.  That is why Boeing was able to "win" while bidding a far higher amount than SNC did.

Perhaps but you could counter argue that both CCtCap companies don't need to be ready at the same time.

NASA's need starts in 2017.  To assume that provider "B" won't be ready in 2017 means that there is higher risk associated with provider "A" being able to be ready by 2017.  While this approach could certainly be used, that is not what NASA requested.  They want to have two providers jockeying to be the first provider.

Quote
Furthermore for $900M more I am sure that SNC could found a way to accelerate those tests...

As much as I wanted the Dream Chaser to be one of the two vehicles chosen, Sierra Nevada was in complete control of what they bid.  No one forced them to bid $900M less than Boeing.  In fact they would not have known what Boeing was bidding, nor SpaceX either, which is part of the "fun" in doing proposals.

So if adding $900M more to their bid would have addressed all of the potential risk items NASA was concerned with, then shame on Sierra Nevada for not bidding it that way.  And from what I understand they could have submitted more than one proposal, so one could have been the lower cost/higher risk one, and the other a higher cost/lower risk one.  However I don't think they could have lowered their risk to a point lower than the CST-100, no matter what they bid, since they still have lots of real life tests that they have to do.

If the GAO upholds NASA's choices, then I think the lesson learned here is that you have to make sure your level of risk is not too far above those you compete with.  At least as far as NASA is concerned.  Which is unfortunate since we need more risk and innovation in space systems in order to lower the overall cost of accessing and staying in space...
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Space Ghost 1962 on 10/14/2014 08:16 pm
If the GAO upholds NASA's choices, then I think the lesson learned here is that you have to make sure your level of risk is not too far above those you compete with.  At least as far as NASA is concerned.  Which is unfortunate since we need more risk and innovation in space systems in order to lower the overall cost of accessing and staying in space...
I must have missed that on Congress's goals ... silly me.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: JasonAW3 on 10/14/2014 09:23 pm
Personally, I think that SNC didn't provide financial support for enough unions, in enough states, thus disqualifying them.  In otherwords, too many hogs for a limited sized trough.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Jim on 10/14/2014 09:41 pm
Personally, I think that SNC didn't provide financial support for enough unions, in enough states, thus disqualifying them.  In otherwords, too many hogs for a limited sized trough.

quite wrong.  Boeing doesn't either by those standards
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: clongton on 10/15/2014 01:55 am
To me that means that Sierra Nevada's proposal was deemed as "not qualified" for an award, because they did not have confidence that SNC could be ready by the 2017 date.  If so, then that only left two potential awardees, SpaceX and Boeing.  That is why Boeing was able to "win" while bidding a far higher amount than SNC did.

The AVWeek article was limited to Girst's personal assessment, yet I notice that you said " because they did not have confidence", switching the emphasis from Girst to the selection committee, about whom we know nothing. I do not doubt that Girst's personal experience influenced his decision but they are based on his years "doing it the old way", which had been successful. Having said that I agree that his viewpoints appear on the face of it to be prejudicial, if not hostile, to anyone approaching the problem in a non-traditional manner. Having read his statement, I suspect that he may have allowed his personal prejudices to override the finding of the selection committee, which finding was made by the numbers according to the selection criteria. If that is true it may be the basis for SNC's protest. Or not. YMMV
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: guckyfan on 10/15/2014 07:44 am
I do not doubt that Girst's personal experience influenced his decision but they are based on his years "doing it the old way", which had been successful.

Your definition of successful may be different than mine.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: yg1968 on 10/15/2014 03:47 pm
NASA's need starts in 2017.  To assume that provider "B" won't be ready in 2017 means that there is higher risk associated with provider "A" being able to be ready by 2017.  While this approach could certainly be used, that is not what NASA requested.  They want to have two providers jockeying to be the first provider. [...]

If the GAO upholds NASA's choices, then I think the lesson learned here is that you have to make sure your level of risk is not too far above those you compete with.  At least as far as NASA is concerned.  Which is unfortunate since we need more risk and innovation in space systems in order to lower the overall cost of accessing and staying in space...

I think that NASA should have adopted the same approach that they did under COTS. They took a big risk by picking SpaceX over more established companies in 2006 and it paid off. SpaceX was late for COTS but NASA will end up paying much less for cargo transportation in the long term for their services. The same thing can be said of Orbital. If commercial crew isn't significantly cheaper than a government option, there is simply no point to the program. The premise behind commercial crew is to take off routine stuff away from NASA and turn it over to the more efficient private sector, so that NASA can concentrate on the harder stuff.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Patchouli on 10/15/2014 04:57 pm
NASA's need starts in 2017.  To assume that provider "B" won't be ready in 2017 means that there is higher risk associated with provider "A" being able to be ready by 2017.  While this approach could certainly be used, that is not what NASA requested.  They want to have two providers jockeying to be the first provider. [...]

If the GAO upholds NASA's choices, then I think the lesson learned here is that you have to make sure your level of risk is not too far above those you compete with.  At least as far as NASA is concerned.  Which is unfortunate since we need more risk and innovation in space systems in order to lower the overall cost of accessing and staying in space...

I think that NASA should have adopted the same approach that they did under COTS. They took a big risk by picking SpaceX over more established companies in 2006 and it paid off. SpaceX was late for COTS but NASA will end up paying much less for cargo transportation in the long term for their services. The same thing can be said of Orbital. If commercial crew isn't significantly cheaper than a government option, there is simply no point to the program. The premise behind commercial crew is to take off routine stuff away from NASA and turn it over to the more efficient private sector, so that NASA can concentrate on the harder stuff.

   Agreed they should have stuck to the original plan.
Despite it's complexity DC appeared to be farther along then the CST-100.
Boeing's drop test vehicle was nothing more then a weighted boiler plate mockup while the SNC's test vehicle was closer to to the flight vehicle then a mockup.
Something similar to the Shuttle ALT test article.
     SNC's landing mode is more proven then the mode chosen by Boeing and Spacex.
Before someone brings up it needs control surfaces it should be noted the presence of control surfaces was not one of the Shuttle's major headaches.
This is based on thoroughly proven aircraft technology and is probably more reliable then the rest of the system.
OT but Blue Origin was the only competitor to actually do an abort test so far.
SNC would be second here as they have the major parts of their abort system.

Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: AncientU on 10/15/2014 05:08 pm
I do not doubt that Girst's personal experience influenced his decision but they are based on his years "doing it the old way", which had been successful.

Your definition of successful may be different than mine.

I believe history's definition will also be different.
A go-nowhere, risk and innovation averse NASA is far removed from success by any measure except in redistributing the wealth of the nation (according to Congressional self-interest).
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Space Ghost 1962 on 10/15/2014 05:57 pm

I think that NASA should have adopted the same approach that they did under COTS. They took a big risk by picking SpaceX over more established companies in 2006 and it paid off. SpaceX was late for COTS but NASA will end up paying much less for cargo transportation in the long term for their services. The same thing can be said of Orbital. If commercial crew isn't significantly cheaper than a government option, there is simply no point to the program. The premise behind commercial crew is to take off routine stuff away from NASA and turn it over to the more efficient private sector, so that NASA can concentrate on the harder stuff.
Remember that Griffin kept ULA and others out of COTS. COTS was pretty much Kistler and it's supposed 70% complete LV yet completely untested. BTW, SpaceX did itself a big favor with the McGregor facility.

Oh, and SpaceX only got in to COTS thru legal action. It is no surprise to me the DC challenge. Nor Congress and its CC gambits. Many of those guys still complain of the waste and the bad way COTS was run. Its a fantastic success.

Perhaps the reason for the success was they didn't believe such a thinly run program would be anything but a failure. Given the capital use profile of Kistler, who outsourced component assemble to US prime aerospace contractors (at the highest possible rates, because they were all one offs with no expectation of follow on -kind of a Johnny Cash "One Piece at a Time" in a multibillion dollar per part junkyard), it would have fed the same mouths and come up short exactly that way.

And once Kistler defaulted, Orbital could swoop in to that position and get established as well. Using Ukrainian and Italian outsourcing as well as antique Russian engines.

The program was kept cheap.

In the CC world view, the "cheap" was underfunded budgets. Which is why Boeing built less than the other two. They wouldn't build more until the budgets were more substantial. Couldn't do COTS "cheap" because the rubric of "safety" for HSF, that makes other HSF (say ... Shuttle ... Orion ... SLS) is expensive. And, program management load to prove its "safe"  is a key program/schedule risk that totally overloads you, even in the normal case.

Every HSF "dollar" is being fought for. I predict more legal challenges in the next year.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Patchouli on 10/15/2014 06:10 pm

Remember that Griffin kept ULA and others out of COTS. COTS was pretty much Kistler and it's supposed 70% complete LV yet completely untested. BTW, SpaceX did itself a big favor with the McGregor facility.

Oh, and SpaceX only got in to COTS thru legal action. It is no surprise to me the DC challenge. Nor Congress and its CC gambits. Many of those guys still complain of the waste and the bad way COTS was run. Its a fantastic success.

Perhaps the reason for the success was they didn't believe such a thinly run program would be anything but a failure. Given the capital use profile of Kistler, who outsourced component assemble to US prime aerospace contractors (at the highest possible rates, because they were all one offs with no expectation of follow on -kind of a Johnny Cash "One Piece at a Time" in a multibillion dollar per part junkyard), it would have fed the same mouths and come up short exactly that way.

And once Kistler defaulted, Orbital could swoop in to that position and get established as well. Using Ukrainian and Italian outsourcing as well as antique Russian engines.

The program was kept cheap.

In the CC world view, the "cheap" was underfunded budgets. Which is why Boeing built less than the other two. They wouldn't build more until the budgets were more substantial. Couldn't do COTS "cheap" because the rubric of "safety" for HSF, that makes other HSF (say ... Shuttle ... Orion ... SLS) is expensive. And, program management load to prove its "safe"  is a key program/schedule risk that totally overloads you, even in the normal case.

Every HSF "dollar" is being fought for. I predict more legal challenges in the next year.

Some early COTS contenders included big names like LM working with PlanetSpace, and smaller but established companies  like SS/L,and Spacehab.

I was actually surprised to see Spacex and Orbital to beat them.

LM had experience with large launch vehicles and the other two vehicles were to make use of existing launchers.

Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: LouScheffer on 10/15/2014 06:23 pm
In terms of "project management skills" and "past performance", I've been able to find very little on SNC.   The most obvious question is how well they have done on projects of similar size and complexity in the past.  There's lots of info on this for Boeing (both good and bad) and at least a little on SpaceX (the cargo contract was $1.6B, at least in the same ballpark).  But I've found very little on SNC, perhaps because many of their projects have been black, or at least grey.

The largest SNC project I could find, apart from DC, was the "Gorgon Stare".  One article ( http://www.wired.com/2009/02/gorgon-stare/ )as of 2009 said this was to be a $150M project, but a 2011 article ( http://www.washingtonpost.com/wp-dyn/content/article/2011/01/24/AR2011012406320.html ) stated that the project cost was $426M as of 2011, and at that time was not working well.   But as of 2014 they were still involved with a later version (http://www.uasvision.com/2014/07/04/increment-2-gorgon-stare-gets-operational-clearance-from-usaf/) so there should be some history here.

And they must have done other large projects.  What were they, and how did they turn out? 
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: yg1968 on 10/15/2014 06:28 pm
Remember that Griffin kept ULA and others out of COTS. COTS was pretty much Kistler and it's supposed 70% complete LV yet completely untested. BTW, SpaceX did itself a big favor with the McGregor facility.

Oh, and SpaceX only got in to COTS thru legal action. It is no surprise to me the DC challenge. Nor Congress and its CC gambits. Many of those guys still complain of the waste and the bad way COTS was run. Its a fantastic success.

SpaceX was a COTS finalist in 2006 at the same time as Kistler. I don't recall any legal actions by SpaceX relating to COTS.

People keep saying that Boeing/LM and ULA were prevented from competing from COTS but Boeing lost out to Orbital in 2008. Boeing would have used a capsule (likely similar to the CST-100) for COTS on a Delta IV.

http://en.wikipedia.org/wiki/Commercial_Orbital_Transportation_Services 
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Jim on 10/15/2014 06:34 pm

1.  SpaceX was a COTS finalist in 2006 at the same time as Kistler. I don't recall any legal actions by SpaceX relating to COTS.

2.  People keep saying that Boeing/LM and ULA were prevented from competing from COTS



1.  COTS existed because Spacex protested the sole source contract to Kistler for launch vehicle flight data.
2. Any spacecraft (HTV, ATV, APEX, CST-100 or ARTCUS) using a Boeing or LM booster was excluded
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: raketa on 10/15/2014 07:05 pm

1.  SpaceX was a COTS finalist in 2006 at the same time as Kistler. I don't recall any legal actions by SpaceX relating to COTS.

2.  People keep saying that Boeing/LM and ULA were prevented from competing from COTS



1.  COTS existed because Spacex protested the sole source contract to Kistler for launch vehicle flight data.
2. Any spacecraft (HTV, ATV, APEX, CST-100 or ARTCUS) using a Boeing or LM booster was excluded
I forgot that wov, but not surprise Kistler have lot of ex NASA folks.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Lars-J on 10/15/2014 07:08 pm
OT but Blue Origin was the only competitor to actually do an abort test so far.
SNC would be second here as they have the major parts of their abort system.

Since SpaceX is gearing up for a pad abort test in a month or so (and a Max-Q one soon thereafter), I highly doubt that SnC would have been able to accomplish that sooner, even if they were selected for CCtCap.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Atomic Walrus on 10/15/2014 08:01 pm
NASA's need starts in 2017.  To assume that provider "B" won't be ready in 2017 means that there is higher risk associated with provider "A" being able to be ready by 2017.  While this approach could certainly be used, that is not what NASA requested.  They want to have two providers jockeying to be the first provider. [...]

If the GAO upholds NASA's choices, then I think the lesson learned here is that you have to make sure your level of risk is not too far above those you compete with.  At least as far as NASA is concerned.  Which is unfortunate since we need more risk and innovation in space systems in order to lower the overall cost of accessing and staying in space...

I think that NASA should have adopted the same approach that they did under COTS. They took a big risk by picking SpaceX over more established companies in 2006 and it paid off. SpaceX was late for COTS but NASA will end up paying much less for cargo transportation in the long term for their services. The same thing can be said of Orbital. If commercial crew isn't significantly cheaper than a government option, there is simply no point to the program. The premise behind commercial crew is to take off routine stuff away from NASA and turn it over to the more efficient private sector, so that NASA can concentrate on the harder stuff.

   Agreed they should have stuck to the original plan.
Despite it's complexity DC appeared to be farther along then the CST-100.
Boeing's drop test vehicle was nothing more then a weighted boiler plate mockup while the SNC's test vehicle was closer to to the flight vehicle then a mockup.
Something similar to the Shuttle ALT test article.
     SNC's landing mode is more proven then the mode chosen by Boeing and Spacex.
Before someone brings up it needs control surfaces it should be noted the presence of control surfaces was not one of the Shuttle's major headaches.
This is based on thoroughly proven aircraft technology and is probably more reliable then the rest of the system.
OT but Blue Origin was the only competitor to actually do an abort test so far.
SNC would be second here as they have the major parts of their abort system.

I'm going to challenge you on that assertion regarding flight hardware:  look at any airport in the world - do you have any doubt that Boeing knows how to build a vehicle or integrate systems?  Successfully completing a critical design review implies a high level of maturity in the design & engineering of the vehicle.  That's what the real work is about in engineering.  If you've done a good job on the design, the fabrication is relatively straightforward. 
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: yg1968 on 10/15/2014 08:08 pm
Quote from: yg1968

1.  SpaceX was a COTS finalist in 2006 at the same time as Kistler. I don't recall any legal actions by SpaceX relating to COTS.

2.  People keep saying that Boeing/LM and ULA were prevented from competing from COTS



1.  COTS existed because Spacex protested the sole source contract to Kistler for launch vehicle flight data.
2. Any spacecraft (HTV, ATV, APEX, CST-100 or ARTCUS) using a Boeing or LM booster was excluded

Thanks for the information. I am still confused according to the COTS Wikipedia entry Planethab and Dream Chaser's proposals both would have used an Atlas V.

You are saying that COTS never would have existed if it wasn't for SpaceX's protest? Wow! I didn't realize that. I didn't follow NSF back then.

http://en.wikipedia.org/wiki/Commercial_Orbital_Transportation_Services
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: RanulfC on 10/16/2014 09:28 pm
I'm going to challenge you on that assertion regarding flight hardware:  look at any airport in the world - do you have any doubt that Boeing knows how to build a vehicle or integrate systems?

While I "challenge" a lot of the specifics in the cited post I'm going to have to "challenge" this comment; I actually HAVE looked around "any airport in the world" and I would say there is a LOT of "doubt" as to whether Boeing knows how to build a SPACE vehicle and intergrated systems by the metrics given. Airplanes are NOT spacecraft and just because you can build one doesn't mean you can build the other by inference. Boeing has had its share of failure even in the aircraft industry and frankly their lack of progress despite being granted more money than the "competition" has been seen by many as a sign they fully expect to be declared the "winner" on name alone.
Quote
Successfully completing a critical design review implies a high level of maturity in the design & engineering of the vehicle.  That's what the real work is about in engineering.  If you've done a good job on the design, the fabrication is relatively straightforward. 

That's not true at all because its in the fabrication and testing of that fabricated item that you really find out if you design works or not. By that metric DC has beaten CST-100 hands down becaue Boeing has CHOOSEN not to fabricate and test but to realy on "design reviews" instead.

Put another way, Boeing fabricated and tested the Bird-of-Prey flight vehicle instead of relying on "design reviews" and computer simulations, why then for something that is supposed to be easier for someone like Boeing have they choosen not to do so with the CST-100?

     SNC's landing mode is more proven then the mode chosen by Boeing and Spacex.

Just a quibble but technically the parachute was invented first and semi-successfully tested before gliding flight was :)

Randy
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: mkent on 10/17/2014 01:44 am

I actually HAVE looked around "any airport in the world" and I would say there is a LOT of "doubt" as to whether Boeing knows how to build a SPACE vehicle and intergrated systems by the metrics given. Airplanes are NOT spacecraft and just because you can build one doesn't mean you can build the other by inference.

While it's not a guarantee, it is a metric to measure the aerospace competence of the various contractors on the Commercial Crew program.

A more relevant one is this: Boeing has designed and built every manned spacecraft NASA has used to launch a crew into space.  X-15, Mercury, Gemini, Apollo CSM, Skylab, Space Shuttle orbiter, and most of the US side of the ISS.  It's all Boeing.

This doubt as to whether Boeing can build a manned spacecraft, especially compared to Sierra Nevada -- who has no manned spacecraft experience at all and whose only unmanned spacecraft are the Orbital OG2 minisatellites and the ChipSat microsatellite -- strikes me as bizarre.  That part of the argument comes across like Bambi vs. Godzilla.  I don't know why it keeps coming up.

Quote
Boeing has had its share of failure even in the aircraft industry and frankly their lack of progress despite being granted more money than the "competition" has been seen by many as a sign they fully expect to be declared the "winner" on name alone.

Lack of progress???  Boeing completed CDR, something neither SpaceX nor Sierra Nevada have done!  Their design is further along than either of their competitors -- SpaceX by a few months but Sierra Nevada by a few years.

That was the entire purpose of the CCiCap contract: to bring an integrated crew system through CDR.  Boeing did that.  Not SpaceX (yet) and not Sierra Nevada.

Quote
Successfully completing a critical design review implies a high level of maturity in the design & engineering of the vehicle.  That's what the real work is about in engineering.  If you've done a good job on the design, the fabrication is relatively straightforward. 

That's not true at all because its in the fabrication and testing of that fabricated item that you really find out if you design works or not.

Those are flight tests, not engineering tests.  Flight tests happen after the vehicle is designed and built.  For Commercial Crew, those tests will occur toward the end of the CCtCap contract in 2017.

The tests that SpaceX, Sierra Nevada, and Boeing have done are all tests of engineering test articles.  That's a completely different level of testing.  All three have done ETA tests.  None have done flight tests of their vehicle designs.

Quote
By that metric DC has beaten CST-100 hands down becaue...

Boeing has done more testing way sooner and retired more risk than Sierra Nevada.  Sierra has four hardware test milestones in its CCiCAP contract.

4) Engineering Test Article Flight Testing (due April 2013 but not yet completed)

This is an approach and landing test the equivalent of Boeing's CCDEV milestone completed in May 2012.

8) Wind Tunnel Testing

Boeing completed their equivalent milestone in October 2011 during CCDev.

9) Risk Reduction & TRL Advancement Testing

Boeing completed their equivalent testing during the CCDev contract.

9a)Main Propulsion & RCS Risk Reduction Testing (not yet completed for the new main propulsion system Sierra Nevada has switched to)

Boeing completed their equivalent milestone in March of 2012 during CCDev.

Sierra Nevada is doing now testing that Boeing completed years ago.

Quote
...Boeing has CHOOSEN not to fabricate and test but to realy on "design reviews" instead.

Boeing, SpaceX, and Sierra Nevada all have to complete a CDR.  It's the primary purpose of the CCiCap contract.  Boeing has completed theirs already.  SpaceX and Sierra Nevada have not.

Quote
Put another way, Boeing fabricated and tested the Bird-of-Prey flight vehicle instead of relying on "design reviews" and computer simulations, why then for something that is supposed to be easier for someone like Boeing have they choosen not to do so with the CST-100?

I absolutely guarantee you that the Bird of Prey went through a CDR.

     SNC's landing mode is more proven then the mode chosen by Boeing and Spacex.

Boeing has completed its landing testing.  Sierra Nevada had only a single failed test.  Their additional testing is running 1-1/2 to 2 years behind schedule.  SpaceX has yet to start DragonFly testing.

The reason Boeing is not doing that testing now is that they're done already.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Rocket Science on 10/17/2014 02:00 am
DC had a flawless test flight up to main gear touch down due to contamination in the F-5E hydraulics which will be not used for th OTV...
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: mkent on 10/17/2014 02:35 am
DC had a flawless test flight up to main gear touch down due to contamination in the F-5E hydraulics which will be not used for th OTV...

"That was some of the best flying I've seen yet - right up to the part where you got killed"

-Jester

 8)
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Rocket Science on 10/17/2014 10:14 am
DC had a flawless test flight up to main gear touch down due to contamination in the F-5E hydraulics which will be not used for th OTV...

"That was some of the best flying I've seen yet - right up to the part where you got killed"

-Jester

 8)
I can be funny too “any landing you can walk away from is a good one”... As a pilot over the years I made some “stinkers” ... The fact remains her aero handling qualities were fine including a 30 knots lower touchdown speed compared to Shuttle... SNC stated from their data that the event would not have caused injuries with crew strapped in...

Edit to add:Look up Chris's article on the test flight.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: llanitedave on 10/17/2014 04:19 pm
DC had a flawless test flight up to main gear touch down due to contamination in the F-5E hydraulics which will be not used for th OTV...

"That was some of the best flying I've seen yet - right up to the part where you got killed"

-Jester

 8)
I can be funny too “any landing you can walk away from is a good one”... As a pilot over the years I made some “stinkers” ... The fact remains her aero handling qualities were fine including a 30 knots lower touchdown speed compared to Shuttle... SNC stated from their data that the event would not have caused injuries with crew strapped in...

Edit to add:Look up Chris's article on the test flight.

So the glide test went well.  But you can't say that Dream Chaser has successfully completed a landing test.  They never even installed their actual landing gear on the vehicle.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: GClark on 10/17/2014 05:45 pm
Perhaps you missed the part where it was an atmospheric test article intended to prove out aerodynamics and software?
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: joek on 10/17/2014 06:46 pm
We'll see when it comes out but the selection statement should indicate how each proposals was evaluated by the selection committee. Gerst has the power to overrule the findings of the selection committee. But if both the selection committee and Gerst say that Boeing's proposal was superior to SNC's, I don't see how SNC can win a challenge. Unfortunately, the AVWeek article doesn't talk about how the proposals were evaluated by the selection committee, they only discuss Gerst's comments.

The source selection authority (SSA, Gerst in this case) may not "overrule" the findings of the source evaluation board (SEB).  The SEB's findings are not comparative; they are what they are, and an input to the SSA's decision.
Quote from: NASA Source Selection Guide
The SEB helps the SSA make the selection by identifying significant discriminators in each of the proposals resulting from its evaluation and explaining the significance of those discriminators. The SEB performs its duties without comparing proposals. It is the responsibility of the SSA to compare proposals using the findings made by the SEB. The SSA exercises independent judgment when determining how these discriminators factor into the selection decision. Since the findings of the SEB are part of the record, the SSA should return the evaluation to the SEB for its further consideration if the SSA believes the SEB’s findings are flawed.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: raketa on 10/17/2014 06:48 pm
NASA's need starts in 2017.  To assume that provider "B" won't be ready in 2017 means that there is higher risk associated with provider "A" being able to be ready by 2017.  While this approach could certainly be used, that is not what NASA requested.  They want to have two providers jockeying to be the first provider. [...]

If the GAO upholds NASA's choices, then I think the lesson learned here is that you have to make sure your level of risk is not too far above those you compete with.  At least as far as NASA is concerned.  Which is unfortunate since we need more risk and innovation in space systems in order to lower the overall cost of accessing and staying in space...

I think that NASA should have adopted the same approach that they did under COTS. They took a big risk by picking SpaceX over more established companies in 2006 and it paid off. SpaceX was late for COTS but NASA will end up paying much less for cargo transportation in the long term for their services. The same thing can be said of Orbital. If commercial crew isn't significantly cheaper than a government option, there is simply no point to the program. The premise behind commercial crew is to take off routine stuff away from NASA and turn it over to the more efficient private sector, so that NASA can concentrate on the harder stuff.
   Agreed they should have stuck to the original plan.
Despite it's complexity DC appeared to be farther along then the CST-100.
Boeing's drop test vehicle was nothing more then a weighted boiler plate mockup while the SNC's test vehicle was closer to to the flight vehicle then a mockup.
Something similar to the Shuttle ALT test article.
     SNC's landing mode is more proven then the mode chosen by Boeing and Spacex.
Before someone brings up it needs control surfaces it should be noted the presence of control surfaces was not one of the Shuttle's major headaches.
This is based on thoroughly proven aircraft technology and is probably more reliable then the rest of the system.
OT but Blue Origin was the only competitor to actually do an abort test so far.
SNC would be second here as they have the major parts of their abort system.

I'm going to challenge you on that assertion regarding flight hardware:  look at any airport in the world - do you have any doubt that Boeing knows how to build a vehicle or integrate systems?  Successfully completing a critical design review implies a high level of maturity in the design & engineering of the vehicle.  That's what the real work is about in engineering.  If you've done a good job on the design, the fabrication is relatively straightforward.

Boeing is great company for mass/repetitive production. Because their little bit out of control overhead during development is evening out  when you will be building thousands product for years without change, this company knows how to do it and know how keep quality of their product high. It is terrible company to develop product that will be build in quantity of dozens. This is not just problem of Boeing, but every big company world wide. I am working on IT industry and have very large experience how good  engineers are force to go to managing position and most of them are not happy there and most of them they don't do good job, because this  is not their passion.But to feed your family, usually not allow to be just great  engineer/programmer/.... Then when you are manger it is very hard to be recognized just by good job, but usually by how much people you are managing.They are naturally press to hire more people, instead how my department could work with same number of people more efficient. I think this is Elon biggest achievement, he is able to broke this spell self growing in his company and tell you, this hell of the fight on the daily bases he has to do. The other staff is easy, find good engineer and give them time money and guidance and they will deliver.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Nindalf on 10/17/2014 08:24 pm
Boeing has designed and built every manned spacecraft NASA has used to launch a crew into space.  X-15, Mercury, Gemini, Apollo CSM, Skylab, Space Shuttle orbiter, and most of the US side of the ISS.  It's all Boeing.
This isn't a good argument.  The ISS wasn't "used to launch a crew into space", and none of the rest was designed or built under the Boeing name or by current Boeing teams.

"Boeing" is just the brand name slapped onto a superconglomerate that formed when most of the American aerospace industry was consolidated into a couple of corporate monsters, due mostly to screwy Wall Street stuff that favored merger after merger.  It's a huge, sprawling organization, so just hearing the name "Boeing" doesn't tell you what engineering or program management is involved.

For instance, "Boeing" made the X-37B, but the people who made that are completely separate from the people who are making CST-100.

There are obviously huge amounts of talent, experience, and competence in Boeing as a whole.  But that says nothing about their ability to compete on any one project with a smaller and more focused company, because there's no way they can bring the entire resources of Boeing to bear on a single project.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: JAFO on 10/18/2014 08:05 am
DC had a flawless test flight up to main gear touch down due to contamination in the F-5E hydraulics which will be not used for th OTV...

"That was some of the best flying I've seen yet - right up to the part where you got killed"

-Jester

 8)

Ironic comment since the F-14 prototype suffered a Class A mishap on it's second flight. DC has been rebuilt, hope they fly her again and let us see what she can do.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Jim on 10/18/2014 03:27 pm

This isn't a good argument.  The ISS wasn't "used to launch a crew into space", and none of the rest was designed or built under the Boeing name or by current Boeing teams.

"Boeing" is just the brand name slapped onto a superconglomerate that formed when most of the American aerospace industry was consolidated into a couple of corporate monsters, due mostly to screwy Wall Street stuff that favored merger after merger.  It's a huge, sprawling organization, so just hearing the name "Boeing" doesn't tell you what engineering or program management is involved.

For instance, "Boeing" made the X-37B, but the people who made that are completely separate from the people who are making CST-100.



Quite the opposite. It is a great argument.  Boeing Huntington beach is supporting both X-37 and CST-100 and there is support from Boeing Houston.  there are people that work both programs, especially since X-37 is long passed the design phase.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Patchouli on 10/18/2014 04:11 pm
Boeing has designed and built every manned spacecraft NASA has used to launch a crew into space.  X-15, Mercury, Gemini, Apollo CSM, Skylab, Space Shuttle orbiter, and most of the US side of the ISS.  It's all Boeing.
This isn't a good argument.  The ISS wasn't "used to launch a crew into space", and none of the rest was designed or built under the Boeing name or by current Boeing teams.

"Boeing" is just the brand name slapped onto a superconglomerate that formed when most of the American aerospace industry was consolidated into a couple of corporate monsters, due mostly to screwy Wall Street stuff that favored merger after merger.  It's a huge, sprawling organization, so just hearing the name "Boeing" doesn't tell you what engineering or program management is involved.

For instance, "Boeing" made the X-37B, but the people who made that are completely separate from the people who are making CST-100.

There are obviously huge amounts of talent, experience, and competence in Boeing as a whole.  But that says nothing about their ability to compete on any one project with a smaller and more focused company, because there's no way they can bring the entire resources of Boeing to bear on a single project.

Rockwell designed and built the Shuttle.
I heard a it was a disaster when Boeing came in with their style of management after the take over.
A lot of innovative work ceased and there was much more red tape.

The X-37B was done by Boeing Phantom which was inherited from McDonnell Douglas which operates sorta like the Lookheed Skunk works and differently form the main company.



Quite the opposite. It is a great argument.  Boeing Huntington beach is supporting both X-37 and CST-100 and there is support from Boeing Houston.  there are people that work both programs, especially since X-37 is long passed the design phase.

I read Boeing went out of their way to keep a lot of the classified IP in the X-37B out of the CST-100 which means the Phantom Works probably had almost nothing to do with the design.

It's funny how DC is more like something the Phantom works would have built then the CST-100.

Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: rayleighscatter on 10/18/2014 04:20 pm
Rockwell designed and built the Shuttle.
Rockwell built the shuttle, they didn't design it.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Robotbeat on 10/18/2014 04:56 pm
...
That was the entire purpose of the CCiCap contract: to bring an integrated crew system through CDR....
That's straight, demonstrably false. CCiCap contracts were competitively bid, and SpaceX's bid included both pad abort and in-flight abort, very ambitious milestones in addition to CDR. Just because Boeing's bid mostly centered around bringing the capsule to CDR does NOT mean it was the "entire purpose." That may have been Boeing's "entire purpose," but it wasn't SpaceX's (or SNC's, for that matter).

Boeing set a lower bar, period. Not surprising they were able to hop over it. Doesn't mean they're "ahead."
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: clongton on 10/18/2014 09:27 pm
Boeing set a lower bar, period. Not surprising they were able to hop over it. Doesn't mean they're "ahead."

That is Boeing sop. Charge the most you can for the least deliverable.
One may not like that but that is how stockholder corp's work - all of them.
That doesn't make it wrong btw. It's called capitalism. It's what feeds the stock market.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: obi-wan on 10/18/2014 09:56 pm
Rockwell designed and built the Shuttle.
Rockwell built the shuttle, they didn't design it.

I was in Shuttle Programs at NASA in the early days (right after Rockwell was awarded the contract); I am at a total loss as to what you mean by this. If Rockwell didn't design it, who did?
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: AJW on 10/18/2014 10:20 pm
Rockwell designed and built the Shuttle.
Rockwell built the shuttle, they didn't design it.

I was in Shuttle Programs at NASA in the early days (right after Rockwell was awarded the contract); I am at a total loss as to what you mean by this. If Rockwell didn't design it, who did?

Drax Industries perhaps?
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Lars-J on 10/19/2014 12:25 am
Rockwell designed and built the Shuttle.
Rockwell built the shuttle, they didn't design it.

I was in Shuttle Programs at NASA in the early days (right after Rockwell was awarded the contract); I am at a total loss as to what you mean by this. If Rockwell didn't design it, who did?

Presumably he means NASA and Rockwell, together. A different kind of relationship (much more hands on from NASA) compared to the commercial crew program.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: yg1968 on 10/19/2014 12:51 am
We'll see when it comes out but the selection statement should indicate how each proposals was evaluated by the selection committee. Gerst has the power to overrule the findings of the selection committee. But if both the selection committee and Gerst say that Boeing's proposal was superior to SNC's, I don't see how SNC can win a challenge. Unfortunately, the AVWeek article doesn't talk about how the proposals were evaluated by the selection committee, they only discuss Gerst's comments.

The source selection authority (SSA, Gerst in this case) may not "overrule" the findings of the source evaluation board (SEB).  The SEB's findings are not comparative; they are what they are, and an input to the SSA's decision.
Quote from: NASA Source Selection Guide
The SEB helps the SSA make the selection by identifying significant discriminators in each of the proposals resulting from its evaluation and explaining the significance of those discriminators. The SEB performs its duties without comparing proposals. It is the responsibility of the SSA to compare proposals using the findings made by the SEB. The SSA exercises independent judgment when determining how these discriminators factor into the selection decision. Since the findings of the SEB are part of the record, the SSA should return the evaluation to the SEB for its further consideration if the SSA believes the SEB’s findings are flawed.

I think that it may work differently this time but previously, there was a grid with colours assigned to each evaluation criteria. Isn't it the selection committee that gives these marks?
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: joek on 10/19/2014 03:39 am
I think that it may work differently this time but previously, there was grid with colours assigned to each evaluation criteria. Isn't it the selection committee that gives these marks?

Yes, the source evaluation board (SEB) does the scoring (evaluation), but the source selection authority (SSA) makes the decision.* The rules and methodology are standardized and codified (both NASA and FAR).  That is invariant, although the details such as specific factors and weights will differ.  However, also remember that CCtCap is under FAR, not an SAA.  The rules are a bit different (generally more constraining) than what you have seen with, e.g., COTS and CCDev.


* edit: there is no "selection committee".
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: yg1968 on 10/19/2014 03:10 pm
I think that it may work differently this time but previously, there was grid with colours assigned to each evaluation criteria. Isn't it the selection committee that gives these marks?

Yes, the source evaluation board (SEB) does the scoring (evaluation), but the source selection authority (SSA) makes the decision.* The rules and methodology are standardized and codified (both NASA and FAR).  That is invariant, although the details such as specific factors and weights will differ.  However, also remember that CCtCap is under FAR, not an SAA.  The rules are a bit different (generally more constraining) than what you have seen with, e.g., COTS and CCDev.


* edit: there is no "selection committee".

OK. Thanks for the clarification. My point was that if Boeing scored the best under the evaluation of the evaluation board and according to Gerst's evaluation, it will be difficult for SNC to win its challenge.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: vt_hokie on 10/19/2014 05:17 pm
Do we have enough cases of such challenges to have a sense of the historical odds of success?  My guess is this is roughly the equivalent of the onside kick in (American) football, or the proverbial Hail Mary pass...
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: joek on 10/19/2014 06:27 pm
@yg1968 @vt_hokie reply in other thread
http://forum.nasaspaceflight.com/index.php?topic=35728.msg1273488#msg1273488
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Jim on 10/19/2014 06:36 pm
Do we have enough cases of such challenges to have a sense of the historical odds of success?  My guess is this is roughly the equivalent of the onside kick in (American) football, or the proverbial Hail Mary pass...

Actually, it is more like a coaches challenge to a touchdown and the video evidence supports the touchdown ruling
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: JasonAW3 on 10/24/2014 04:25 pm
Are they still going to build the full scale beast or is that a dead subject?
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Nindalf on 10/24/2014 04:31 pm
Are they still going to build the full scale beast or is that a dead subject?
It's still not settled whether they're grabbing the CC contract away from Boeing.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: yg1968 on 10/30/2014 02:37 pm
The Antares failure has me thinking about DC's launch abort system. Could DC have survived such an explosion if it had happened to its LV (i.e., the Atlas V 512)? Are the engines on DC powerful enough for it to outrun an exploding LV?
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Robotbeat on 10/30/2014 02:53 pm
The Antares failure has me thinking about DC's launch abort system. Could DC have survived such an explosion if it had happened to its LV (i.e., the Atlas V 512)? Are the engines on DC powerful enough for it to outrun an exploding LV?
Antares fell back toward the pad. I think in that specific case Dreamchaser would've been fine most likely.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: yg1968 on 10/30/2014 02:58 pm
The Antares failure has me thinking about DC's launch abort system. Could DC have survived such an explosion if it had happened to its LV (i.e., the Atlas V 512)? Are the engines on DC powerful enough for it to outrun an exploding LV?
Antares fell back toward the pad. I think in that specific case Dreamchaser would've been fine most likely.

OK, thanks. But I still don't understand how their abort system works. Can DC outrun an exploding rocket that is still going up?
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Robotbeat on 10/30/2014 03:05 pm
The Antares failure has me thinking about DC's launch abort system. Could DC have survived such an explosion if it had happened to its LV (i.e., the Atlas V 512)? Are the engines on DC powerful enough for it to outrun an exploding LV?
Antares fell back toward the pad. I think in that specific case Dreamchaser would've been fine most likely.

OK, thanks. But I still don't understand how their abort system works. Can DC outrun an exploding rocket that is still going up?
I believe so, at least if the problem occurs in the first stage where acceleration is lower.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: yg1968 on 10/30/2014 03:09 pm
The Antares failure has me thinking about DC's launch abort system. Could DC have survived such an explosion if it had happened to its LV (i.e., the Atlas V 512)? Are the engines on DC powerful enough for it to outrun an exploding LV?
Antares fell back toward the pad. I think in that specific case Dreamchaser would've been fine most likely.

OK, thanks. But I still don't understand how their abort system works. Can DC outrun an exploding rocket that is still going up?
I believe so, at least if the problem occurs in the first stage where acceleration is lower.

You are not sure about an explosion of the second stage (the dual centaur)?

Is your answer any different if SNC elects to keep its hybrid engines?
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Robotbeat on 10/30/2014 03:20 pm
For a liquid rocket, you just shut off the engines. If there's a major RUD, the engines will stop producing much thrust, so getting away is easy (ish). And I assume DC sized the propulsion in either case to allow sufficient thrust to get away.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: ugordan on 10/30/2014 03:29 pm
You are not sure about an explosion of the second stage (the dual centaur)?

Keep in mind the Centaur operates in vacuum and the risk of a shockwave-generating event is much lower. Liquid stages don't typically explode, they could lose structural integrity but even that is pretty unlikely once you're out of a high Q environment.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: yg1968 on 10/30/2014 03:50 pm
For a liquid rocket, you just shut off the engines. If there's a major RUD, the engines will stop producing much thrust, so getting away is easy (ish). And I assume DC sized the propulsion in either case to allow sufficient thrust to get away.

OK, thanks. So running away from the rocket is more of an issue for a rocket that has a solid rocket booster because it can't get turned off. I am assuming that the solid rocket on the Atlas V 412 is not an issue because it is much lower than DC?
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Patchouli on 10/30/2014 06:26 pm
For a liquid rocket, you just shut off the engines. If there's a major RUD, the engines will stop producing much thrust, so getting away is easy (ish). And I assume DC sized the propulsion in either case to allow sufficient thrust to get away.

The two worst parts of abort are during a pad fall back like what happened with Antares and at max Q.
Air launching pretty much eliminates the first problem.

I wonder could SNC have delivered both versions of DC for the same price as Boeing is charging for the CST-100?

In that case it they would be getting effectively two largely redundant launch systems.

Though the second smaller version would carry much less but you'd still have basic crew rotation capability.

Interestingly the standard version of Cygnus probably can fit on Stratolaunch.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Danderman on 10/31/2014 06:24 pm
Today's news does not bode well for a continued future for DC.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: docmordrid on 10/31/2014 06:29 pm
Not with a hybrid engine, I would think.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: yg1968 on 10/31/2014 06:45 pm
Today's news does not bode well for a continued future for DC.

Their hybrid engine has no future. Time to announce a switch.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: simonbp on 10/31/2014 09:41 pm
Today's news does not bode well for a continued future for DC.

Their hybrid engine has no future. Time to announce a switch.

They already did, back in August... http://www.parabolicarc.com/2014/08/19/snc-abandons-hybrid-motors-dream-chaser/

In fact the immaturity of the new liquid engines was the major engineering criticism of DC in the source selection document.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Lars-J on 10/31/2014 09:55 pm

Today's news does not bode well for a continued future for DC.

Their hybrid engine has no future. Time to announce a switch.

They already did, back in August... http://www.parabolicarc.com/2014/08/19/snc-abandons-hybrid-motors-dream-chaser/

In fact the immaturity of the new liquid engines was the major engineering criticism of DC in the source selection document.

SNC has never acknowledged officially that they were switching the engine technology. Most of us knew it must be true based on information trickling out, but they never acknowledged it publicly.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: mmeijeri on 10/31/2014 09:56 pm
Their hybrid engine has no future.

Perhaps not, but if it was the nitrous oxide tank that exploded today, then that indicates a problem with nitrous oxide more than a problem with hybrids.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: simonbp on 10/31/2014 10:43 pm
Their hybrid engine has no future.

Perhaps not, but if it was the nitrous oxide tank that exploded today, then that indicates a problem with nitrous oxide more than a problem with hybrids.

I'd argue the contrary. IF it turns out out the root cause of the explosion was the pressurized NOX tank, that is pretty damning for the safety of all pressure-fed rockets, including all current hybrid rockets. Pressure-fed rockets have been sold for decades (literally, since the mid 1960s) as being safer than turbopump-fed rockets, most notably as an alternative to the Shuttle SRBs.

There are reasons why SNC suddenly dropped their cherished hybrids like a hot potato earlier this year. Those reasons will hopefully come out in the NTSB report.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: mmeijeri on 10/31/2014 10:48 pm
I'd argue the contrary. IF it turns out out the root cause of the explosion was the pressurized NOX tank, that is pretty damning for the safety of all pressure-fed rockets, including all current hybrid rockets.

I agree that it could indeed be an argument against pressure-fed rockets, though hybrids could be pump-fed too. This accident made me realise that what's safer on the moon (pressure-fed) isn't necessarily what's safer in the Earth's atmosphere (pumps + lower tank pressure).
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: llanitedave on 11/01/2014 12:41 am
Pumps are a major failure point too.  I don't think it's clear that the failure of a particular pressurized tank proves a flaw in the concept, or an automatic superiority for pump-fed.  No sense in jumping to extreme conclusions.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: adrianwyard on 11/06/2014 12:55 am
Q: If Kerosene+Liquid Oxygen is known as 'kerolox', and Hydrogen+LOX is 'hydrolox', what's the abbreviation for  Propane+Nitrous? I vote for 'propostrous'.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: yg1968 on 11/06/2014 01:33 am
I believe these images (from the above paper) are the first we've seen of the Nitrous/Propane main propulsion system and RCS:

Although not a surprise, it's also the first time that they have officially stated that the hybrids have been dropped in favour of this new liquid system.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Moe Grills on 11/06/2014 06:22 pm

Today's news does not bode well for a continued future for DC.

Their hybrid engine has no future. Time to announce a switch.

Politics, man. Business politics. It will never change.
They already did, back in August... http://www.parabolicarc.com/2014/08/19/snc-abandons-hybrid-motors-dream-chaser/

In fact the immaturity of the new liquid engines was the major engineering criticism of DC in the source selection document.

SNC has never acknowledged officially that they were switching the engine technology. Most of us knew it must be true based on information trickling out, but they never acknowledged it publicly.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Moe Grills on 11/06/2014 06:31 pm
  I think the idea of "vertical" launch crewed space planes/gliders like the retired shuttles, or planned DC winged craft are going the way of the dinosaur.

  It makes little difference to a crew's chances for survival (very small or none) if their winged craft is bolted to the top or the sides of booster that is either seconds into LO (less than 100 meters above pad) or violently comes apart a minute into the ascent.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: mheney on 11/06/2014 07:05 pm
  I think the idea of "vertical" launch crewed space planes/gliders like the retired shuttles, or planned DC winged craft are going the way of the dinosaur.

  It makes little difference to a crew's chances for survival (very small or none) if their winged craft is bolted to the top or the sides of booster that is either seconds into LO (less than 100 meters above pad) or violently comes apart a minute into the ascent.

But the advantage to vertical launching is that you don't have to support the weight of your fully-fuelled vehicle on
landing gear.  Instead, all that weight is supported by the thrust structure as it sits on the pad - and continues to support it (as it must) in-flight.   You end up with a lighter structure overall by going with vertical launch - regardless of your landing method.

(As far as being on top of vs. hanging off the side - the primary concern is protecting the heat shield from
damage during launch.   That seems easier if the vehicle os in top ...)
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: mike robel on 11/06/2014 07:10 pm
Unless of course returned cargo weighs as much as the delivered cargo.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: MattMason on 11/06/2014 07:17 pm
The Antares failure has me thinking about DC's launch abort system. Could DC have survived such an explosion if it had happened to its LV (i.e., the Atlas V 512)? Are the engines on DC powerful enough for it to outrun an exploding LV?
Antares fell back toward the pad. I think in that specific case Dreamchaser would've been fine most likely.

OK, thanks. But I still don't understand how their abort system works. Can DC outrun an exploding rocket that is still going up?

If I recall the Commercial Crew requirements, they'd have to build in an active launch abort system for any mode (stationary, near-pad, and in-flight) for NASA to consider them. Given the DC's resemblance to the Orbiter, and given its lack of a LAS, this couldn't be ignored by SNC.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: mheney on 11/06/2014 07:20 pm
It's not the cargo up/down - it's the fuel.  Moe Grills was commenting on vertical launch; the alternative - horizontal launch - requires being able to handle the weight of a fully loaded vehicle in multiple directions (vie thrust structure in flight, via your landing gear while awaiting launch.)    Rolling down a runway with a fully fuelled vehicle requires MUCH more robust (read: heavy) gear and structure than sitting on your tail does.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: JAFO on 11/08/2014 06:54 pm
Any word on the EFT, Chris? Still in Colorado on hold or are they still planning to fly her?
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: BrightLight on 11/26/2014 05:40 pm
SNC, Stratolaunch expand on proposed Dream Chaser flights - by Chris Gebhardt:
http://www.nasaspaceflight.com/2014/11/snc-stratolaunch-dream-chaser-flights/

Very nice article Chris - The matching of Stratolauch to DC is way cool and if it works, a potentially low cost access for manned space flight. Its a shame that the Startolaunch option requires a 25% reduced size DC other wise it would be a excellent challenger to Boeing and SpaceX.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: BrightLight on 11/26/2014 06:20 pm
With a 75% scaled DC, a mission to ISS would have some issues including a LIDS in the rear of the DC.  I have superimposed a 100% LIDS (blue shade) from DC onto the rear of the scaled DC. Its more then a tight fit but if the DC is flared in the back by just a few centimeters it can be done.  This clearly would require changing the mold lines a bit - something SNC might not want to do.

the image came from: http://orbiter-forum.com/showthread.php?t=31010&page=3 created by Chuck Tetakel, btw, his work is fantastic.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: A_M_Swallow on 11/26/2014 07:48 pm
With a 75% scaled DC, a mission to ISS would have some issues including a LIDS in the rear of the DC.  I have superimposed a 100% LIDS (blue shade) from DC onto the rear of the scaled DC. Its more then a tight fit but if the DC is flared in the back by just a few centimeters it can be done.  This clearly would require changing the mold lines a bit - something SNC might not want to do.

the image came from: http://orbiter-forum.com/showthread.php?t=31010&page=3 created by Chuck Tetakel, btw, his work is fantastic.

Could the LIDS replace the entrance on top of the cabin?
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Patchouli on 11/27/2014 06:28 am
With a 75% scaled DC, a mission to ISS would have some issues including a LIDS in the rear of the DC.  I have superimposed a 100% LIDS (blue shade) from DC onto the rear of the scaled DC. Its more then a tight fit but if the DC is flared in the back by just a few centimeters it can be done.  This clearly would require changing the mold lines a bit - something SNC might not want to do.

the image came from: http://orbiter-forum.com/showthread.php?t=31010&page=3 created by Chuck Tetakel, btw, his work is fantastic.

Another solution they could have the LIDS interface on a non reusable part and ditch it during reentry like Soyuz and the Kliper Space plane.
Not sure how much this would effect the costs but it could allow more up cargo volume or modules for alternative missions such as airlocks or nano sat dispensers.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: BrightLight on 11/27/2014 01:46 pm
With a 75% scaled DC, a mission to ISS would have some issues including a LIDS in the rear of the DC.  I have superimposed a 100% LIDS (blue shade) from DC onto the rear of the scaled DC. Its more then a tight fit but if the DC is flared in the back by just a few centimeters it can be done.  This clearly would require changing the mold lines a bit - something SNC might not want to do.

the image came from: http://orbiter-forum.com/showthread.php?t=31010&page=3 created by Chuck Tetakel, btw, his work is fantastic.

Another solution they could have the LIDS interface on a non reusable part and ditch it during reentry like Soyuz and the Kliper Space plane.
Not sure how much this would effect the costs but it could allow more up cargo volume or modules for alternative missions such as airlocks or nano sat dispensers.
If the Stratolaunch LV can carry the mass of the module, why not instead use a larger DC that can mount the LIDS?
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Patchouli on 11/27/2014 03:02 pm

If the Stratolaunch LV can carry the mass of the module, why not instead use a larger DC that can mount the LIDS?

The module should weigh much less then a scaled up DC since it does not need to be supported with recovery systems much in the same way Soyuz's use of a OM saves mass.
The Soyuz OM and DM weigh less then the Apollo CM even though though together have more total volume.
Plus in mini DC's case it might also be able to double as part of the LV adapter as seen in this later Hermes concept.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: BrightLight on 11/27/2014 04:15 pm

If the Stratolaunch LV can carry the mass of the module, why not instead use a larger DC that can mount the LIDS?

edited by Brightlight to reduce the size.
Plus in mini DC's case it might also be able to double as part of the LV adapter as seen in this later Hermes concept.
If the module can also act as the LV adapter and reduce weight that might make more sense.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Lars-J on 11/27/2014 04:18 pm

With a 75% scaled DC, a mission to ISS would have some issues including a LIDS in the rear of the DC.  I have superimposed a 100% LIDS (blue shade) from DC onto the rear of the scaled DC. Its more then a tight fit but if the DC is flared in the back by just a few centimeters it can be done.  This clearly would require changing the mold lines a bit - something SNC might not want to do.

the image came from: http://orbiter-forum.com/showthread.php?t=31010&page=3 created by Chuck Tetakel, btw, his work is fantastic.

Another solution they could have the LIDS interface on a non reusable part and ditch it during reentry like Soyuz and the Kliper Space plane.
Not sure how much this would effect the costs but it could allow more up cargo volume or modules for alternative missions such as airlocks or nano sat dispensers.
If the Stratolaunch LV can carry the mass of the module, why not instead use a larger DC that can mount the LIDS?

It can't. This concept uses a 75% scale DC (~50% mass) because that is the limit that Stratolauncher can put in LEO. There is no margin.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: BrightLight on 11/27/2014 04:26 pm

With a 75% scaled DC, a mission to ISS would have some issues including a LIDS in the rear of the DC.  I have superimposed a 100% LIDS (blue shade) from DC onto the rear of the scaled DC. Its more then a tight fit but if the DC is flared in the back by just a few centimeters it can be done.  This clearly would require changing the mold lines a bit - something SNC might not want to do.

the image came from: http://orbiter-forum.com/showthread.php?t=31010&page=3 created by Chuck Tetakel, btw, his work is fantastic.

Another solution they could have the LIDS interface on a non reusable part and ditch it during reentry like Soyuz and the Kliper Space plane.
Not sure how much this would effect the costs but it could allow more up cargo volume or modules for alternative missions such as airlocks or nano sat dispensers.
If the Stratolaunch LV can carry the mass of the module, why not instead use a larger DC that can mount the LIDS?

It can't. This concept uses a 75% scale DC (~50% mass) because that is the limit that Stratolauncher can put in LEO. There is no margin.
that is what i suspected.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Patchouli on 11/27/2014 04:57 pm
The most interesting thing about this concept is the number of ISS launch opportunities it offers.
Plus it eliminates the supply issues with Russian engines.

I wonder if OSC might put a version of Cygnus on Stratolaunch for the same reasons?

Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: adrianwyard on 12/09/2014 04:37 pm
I wonder if knowledgable people here think the following application of hybrid rocket technology is also likely to hit the problems that SS2/DC ran into:

https://www.youtube.com/watch?v=22_4ZGGnb_g

In this case it's HTPB and HTP rather than N2O. The plume looks pretty stable in the video...

From the look of the test stand it was locked down well and they were interested in measuring thrust. But when this is on wheels going 1000mph, any combustion instability that results in the slightest pitch or yaw moment is going to be problematic, right?
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: woods170 on 12/20/2014 08:18 pm
Commentary on Dreamchaser, the protest and the future of commercial spaceflight.

http://spacenews.com/commentary-litigating-the-end-of-a-dream/ (http://spacenews.com/commentary-litigating-the-end-of-a-dream/)

Spacenews usually has good stuff. But this op-ed contains a good number of glaring mistakes and (wrong) assumptions.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: vt_hokie on 12/21/2014 02:14 am
Good find nonetheless, thanks for sharing.  I can't tell you how sad it makes me that Dream Chaser has come so far for such a modest investment, and now we're just going to let it wither on the vine.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: JAFO on 12/21/2014 04:47 am
Good find nonetheless, thanks for sharing.  I can't tell you how sad it makes me that Dream Chaser has come so far for such a modest investment, and now we're just going to let it wither on the vine.

Yup. Sorry, Saint Leibowitz, they've stopped dreaming down here.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: ChrisWilson68 on 12/21/2014 06:38 am
The most interesting thing about this concept is the number of ISS launch opportunities it offers.

It's a solution in search of a problem.

Air launch is cool.  Really big aircraft are cool.  Spaceplanes are cool.  But just because things are appealing doesn't mean they're the best choices.  And these things turn out to be worse choices than the simpler, frumpier alternatives -- ground launch and capsules.  So people go looking for ways to justify their emotional attachment to the cool choices.

Operations to send people and supplies to the ISS are not constrained by not having enough launch opportunities.  Having a launch delayed a bit doesn't have a big impact -- not enough to make up for the substantial disadvantages to air launching.

Plus it eliminates the supply issues with Russian engines.

I wonder if OSC might put a version of Cygnus on Stratolaunch for the same reasons?

Only if Stratolaunch is cheaper.  That's the only advantage that really matters for OSC.  So far, there's no evidence Stratolaunch will be cheaper.  They add a very large first stage that provides only modest performance improvements.  It's likely to be much more expensive than ground launch.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: vt_hokie on 12/23/2014 05:06 am
Is it fair to say that perhaps SNC was being less than forthright in saying that the DC orbital test vehicle would fly on Atlas V regardless of NASA's decision?
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Patchouli on 12/23/2014 07:27 pm
Good find nonetheless, thanks for sharing.  I can't tell you how sad it makes me that Dream Chaser has come so far for such a modest investment, and now we're just going to let it wither on the vine.
Yah it is disappointing esp when they tried so hard while Boeing on the other hand won with a design that made few attempts to do anything innovative and was just good enough to meet the minimum requirements.
In fact I would say Boeing's attempt was somewhat lazy in contrast to SNCs and Spacex's.

The most interesting thing about this concept is the number of ISS launch opportunities it offers.

Only if Stratolaunch is cheaper.  That's the only advantage that really matters for OSC.  So far, there's no evidence Stratolaunch will be cheaper.  They add a very large first stage that provides only modest performance improvements.  It's likely to be much more expensive than ground launch.

It has an expensive first stage but that first stage is reusable.
Air launching generally requires less in the way of unique ground support infrastructure and is less susceptible to range availability issues and weather delays then a ground launched rocket.
You also no longer have pad fall back as a failure mode as what happened with Antares.
In the end air launching might actually be cheaper and safer in the long run.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: rayleighscatter on 12/23/2014 08:28 pm
Is it fair to say that perhaps SNC was being less than forthright in saying that the DC orbital test vehicle would fly on Atlas V regardless of NASA's decision?
SNC said quite a few times that DC wasn't launcher specific.

For commercial crew though they had to pick a launcher for their proposal. They couldn't write up proposals for an Atlas V/Falcon 9/Ariane/etc. and ask NASA to pick their favorite, for the competition, they had to pick one.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: vt_hokie on 12/24/2014 05:22 am
Is it fair to say that perhaps SNC was being less than forthright in saying that the DC orbital test vehicle would fly on Atlas V regardless of NASA's decision?
SNC said quite a few times that DC wasn't launcher specific.

For commercial crew though they had to pick a launcher for their proposal. They couldn't write up proposals for an Atlas V/Falcon 9/Ariane/etc. and ask NASA to pick their favorite, for the competition, they had to pick one.

I'm referring specifically to Mark Sirangelo stating on the record that they had purchased an Atlas V for the 2016 OTV launch and that was happening regardless of NASA's commercial crew decision.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Lars-J on 12/24/2014 06:51 am
I'm referring specifically to Mark Sirangelo stating on the record that they had purchased an Atlas V for the 2016 OTV launch and that was happening regardless of NASA's commercial crew decision.

Yeah... I don't think that is happening. They were definitely stretching the truth there, if not outright lying. But I would  be happy to be proven wrong!
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Patchouli on 12/24/2014 09:15 am

What would be the commercial reason for proposing such a system?

Cheers, Martin

Same reasons as SNC and Spacex the per mission cost could be lower and the landings would be more controlled and gentle.
But big companies often are risk adverse.
It actually is surprising Boeing even seriously competed for commercial crew at all after taking a big risk on developing the 787 which must have made the share holders antsy.

Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: baldusi on 12/24/2014 06:04 pm
Could that slot be the one Orbital will use for CRS-4?
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: ChrisWilson68 on 12/24/2014 10:33 pm
Yah it is disappointing esp when they tried so hard while Boeing on the other hand won with a design that made few attempts to do anything innovative and was just good enough to meet the minimum requirements.

What if a capsule really is a better choice, given today's technology?  I'd hate to think we'd punish those who make the optimal choice just because it isn't flashy enough.

In fact I would say Boeing's attempt was somewhat lazy in contrast to SNCs and Spacex's.

I just don't see the evidence to back that up.

The most interesting thing about this concept is the number of ISS launch opportunities it offers.

Only if Stratolaunch is cheaper.  That's the only advantage that really matters for OSC.  So far, there's no evidence Stratolaunch will be cheaper.  They add a very large first stage that provides only modest performance improvements.  It's likely to be much more expensive than ground launch.

It has an expensive first stage but that first stage is reusable.

Expensive but reusable doesn't always lead to lowest overall cost.  I think the Shuttle program proved that.

The point is that with air launch that really expensive first stage really doesn't buy you much delta-v.  So the second stage of your air launch vehicle isn't really that much smaller than the first stage of a comparable ground launch vehicle.

Air launching generally requires less in the way of unique ground support infrastructure and is less susceptible to range availability issues and weather delays then a ground launched rocket.
You also no longer have pad fall back as a failure mode as what happened with Antares.
In the end air launching might actually be cheaper and safer in the long run.

Yes, there are advantages to air launch.  But there are also disadvantages.  I'm not convinced you actually need less ground support infrastructure with air launch.  Vehicle integration still needs to happen.  I don't see why the rocket itself would need less support in the lead-up to launch than it would from the ground.  It's just more complex and difficult to provide that support because now the last hour or so before the rocket lights you're in the air.  How do you top up the LOX that has boiled away, for example?  It's a whole lot easier to do that on the ground than on an aircraft flying at 40,000 feet.

With air launch, how do you do a static fire?  Or a hold-down?  You really can't.  When Falcon 9 fires up its engines, if they don't all come up, the hold downs don't release, they shut down and recycle for an hour or day or week later.  If the engines on the rocket that's air launched don't fire, the stage falls in the ocean.

And lets talk failure modes.  It's true that you don't have the same likelihood of a rocket falling back on the pad.  But instead you have a crew that needs to be close to a fully-loaded rocket for an extended period and through potentially dangerous operations.  With ground launch, no human goes near the rocket after fueling starts.  Not so with air launch, unless you're going to make it a drone aircraft, when Air Launch LLC has said they are not doing.  So now your failure modes include people dying on launches of uncrewed vehicles.  Is that really an improvement over having the rocket take out a pad?
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Mike Harris-Stone on 12/24/2014 11:30 pm
Is it fair to say that perhaps SNC was being less than forthright in saying that the DC orbital test vehicle would fly on Atlas V regardless of NASA's decision?

SNC is still proceeding on the full scale Dreamchaser.  They recently completed a propulsion milestone.  Also Kathy Lueders recently wrote that another drop test was coming in 2015. 

"Sierra Nevada Corporation (SNC) performed incremental tests of its reaction control system that will help maneuver its Dream Chaser spacecraft in space. SNC achieved its CCiCap milestone in November and built on previous propulsion system development efforts by implementing a compact prototype thruster operating in a vacuum chamber to simulate an on-orbit environment.

This year, the company also performed wind tunnel and risk-reduction testing under its CCiCap agreement and closed out its Certification Products Contract with NASA. In 2015, the company will perform the second free-flight of its Dream Chaser test article at NASA's Armstrong Flight Research Center."



Until someone says the Atlas V test is cancelled, it is still potentially on.  (Has anyone heard something different?)

There also seems to be confusion in this thread between the Dream Chaser which would launch on an Atlas V and the air dropped variation being discussed by Stratolaunch.  The original Dream Chaser project hasn't been cancelled yet.  SNC could still win their protest, SNC could win CRS 2 or some other international customer for Dream Chaser could step forward.  It's far from over at least from the outside.  The Stratolaunch version could happen too, but it's really a different vehicle.

Does anyone have any inside information to share?  :)
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Patchouli on 12/25/2014 01:21 am

What if a capsule really is a better choice, given today's technology?  I'd hate to think we'd punish those who make the optimal choice just because it isn't flashy enough.
The thing is we don't really know what an optimal design is yet.
 I'd prefer three vehicles of different designs but they decided to down select to two.
 I think Spacex is very innovative with their vehicle even though it's a capsule as they're trying things no one has even considered.
They did some some stuff you'd normally only see on a space plane vehicle such as integration of the propulsion system into the reentry vehicle.
DC was less then the CST-100 so I figure it would the the obvious choice for a second vehicle and the fact it's something different and innovative was a plus.
The CST-100 is the lowest risk vehicle as it pretty much been there done that stuff.

But maybe SNC will find another backer for their vehicle.

I got to thinking mini DC on Soyuz could be good low cost crew transport solution for the ESA.
Though Araine 5 and 6 could easily lift the full sized version.

Quote
And lets talk failure modes.  It's true that you don't have the same likelihood of a rocket falling back on the pad.  But instead you have a crew that needs to be close to a fully-loaded rocket for an extended period and through potentially dangerous operations.  With ground launch, no human goes near the rocket after fueling starts.  Not so with air launch, unless you're going to make it a drone aircraft, when Air Launch LLC has said they are not doing.  So now your failure modes include people dying on launches of uncrewed vehicles.  Is that really an improvement over having the rocket take out a pad?


Liquid fueled rockets have been air launched hundreds of times during the various X programs without any serious incidents that resulted in destruction of the carrier vehicle.
Pegasus has been launched 47 times no issue of that sort.

Out side of some early tests LVs generally don't go boom for no reason usually it's because of high speed contact with he ground or the flight termination system blowing it up when it goes off course etc.
Though Pegasus II is mostly solid fueled but simplifying handling and fueling is likely the primary reason.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: newpylong on 12/26/2014 01:28 pm
Could that slot be the one Orbital will use for CRS-4?

Considering CRS-4 will be in 2015 and SNC was notionally scheduled for 2016, not likely.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: ChrisWilson68 on 12/27/2014 04:30 am

What if a capsule really is a better choice, given today's technology?  I'd hate to think we'd punish those who make the optimal choice just because it isn't flashy enough.
The thing is we don't really know what an optimal design is yet.

Maybe we don't, but maybe SpaceX and Boeing do.

My point is we shouldn't be putting a thumb on the scale to give preference to a company just because they choose a space plane over a capsule.  The companies that chose capsules might have very good reasons for doing so.

There might be good reasons for choosing SNC over Boeing or SpaceX.  But "they chose a space plane and that's more innovative" is not one of them.

I'd prefer three vehicles of different designs but they decided to down select to two.

When you have limited resources, it's often better to focus them than spread them too thinly.  Sometimes you have to make a choice.

We don't have enough business, really, for even two service providers of commercial crew to the ISS.  Even with two, that's about one flight per year per provider.  Not nearly enough!  Spreading it among three providers just makes it that much harder for any of them to really be viable, and makes each one more expensive.

What we desperately need is to make things less expensive.  You don't make things less expensive by giving too little business to each provider.

I got to thinking mini DC on Soyuz could be good low cost crew transport solution for the ESA.
Though Araine 5 and 6 could easily lift the full sized version.

DC is not low cost.  If ESA really wanted to fly astronauts on an American crew vehicle on Ariane 5 or 6, it would be much cheaper to put CST-100 or Dragon 2 on Ariane, because the US government is already paying the development costs of those vehicles.

Of course, there's no chance ESA is going to put an American vehicle on Ariane 5 or 6 at all.  They'll either continue to send them up with NASA and/or Russia or build their own crew vehicle.

Quote
And lets talk failure modes.  It's true that you don't have the same likelihood of a rocket falling back on the pad.  But instead you have a crew that needs to be close to a fully-loaded rocket for an extended period and through potentially dangerous operations.  With ground launch, no human goes near the rocket after fueling starts.  Not so with air launch, unless you're going to make it a drone aircraft, when Air Launch LLC has said they are not doing.  So now your failure modes include people dying on launches of uncrewed vehicles.  Is that really an improvement over having the rocket take out a pad?


Liquid fueled rockets have been air launched hundreds of times during the various X programs without any serious incidents that resulted in destruction of the carrier vehicle.

Suborbital rocket-powered planes aren't really comparable to orbital launchers.

Pegasus has been launched 47 times no issue of that sort.

Pegasus is much smaller.  It doesn't mean a much larger vehicle wouldn't have dangers.  And even if there's a 2% fatal accident rate with Pegasus, there would still be a good chance we haven't seen it yet, and 2% fatal accident rate isn't really acceptable.

Out side of some early tests LVs generally don't go boom for no reason usually it's because of high speed contact with he ground or the flight termination system blowing it up when it goes off course etc.
Though Pegasus II is mostly solid fueled but simplifying handling and fueling is likely the primary reason.

But it does happen sometimes.  It's not something that can be ignored as a possibility.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: jongoff on 12/27/2014 05:17 am
I'm referring specifically to Mark Sirangelo stating on the record that they had purchased an Atlas V for the 2016 OTV launch and that was happening regardless of NASA's commercial crew decision.

Yeah... I don't think that is happening. They were definitely stretching the truth there, if not outright lying. But I would  be happy to be proven wrong!

Yeah, at the time Mark made those comments, I took them with the same sized grain of salt as I took similar claims by ATK that it was going to build Liberty regardless of its Commercial Crew success. I'd be really surprised if SNC put down more than the minimum deposit to secure the flight.

Also, while I can't seem to confirm it with a quick google search, I seem to recall Mark's background was originally a lawyer of some sort--which means that it may matter knowing exactly what he said, as lawyers (even honest ones) tend to phrase their public statements a lot more carefully than the rest of us slobs.

~Jon
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: DGH on 01/05/2015 10:47 am
If memory serves today is the 100 day mark.
So with luck we should see the decision today or tomorrow.
Anybody know if this is correct?
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Galactic Penguin SST on 01/05/2015 01:09 pm
If memory serves today is the 100 day mark.
So with luck we should see the decision today or tomorrow.
Anybody know if this is correct?

Just confirmed:

Marcia Smith @SpcPlcyOnline
GAO atty handling the Sierra Nevada bid protest just confirmed the decision will be anncd today, w/a GAO press release sometime this pm.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Lars-J on 01/05/2015 04:09 pm
From the update thread:
U.S. GAO has denied Sierra Nevada bid protest of NASA's Commercial Crew contract awards to Boeing, SpaceX.

GAO "found no undue emphasis" on NASA’s consideration of proposed schedules or likelihood of meeting 2017 goal.

https://twitter.com/flatoday_jdean/status/552142421979824128
https://twitter.com/flatoday_jdean/status/552142881314844672

So... The SNC protest was rejected.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: AnalogMan on 01/05/2015 04:15 pm
http://www.gao.gov/press/pr_statement_sierra_nevada_bid_protest.htm (http://www.gao.gov/press/pr_statement_sierra_nevada_bid_protest.htm)

Press Release
Statement on Sierra Nevada Bid Protest Decision

The following is a statement from Ralph O. White, Managing Associate General Counsel for Procurement Law at GAO, regarding today’s decision resolving a protest filed by Sierra Nevada Corp., B-410485, et al., January 5, 2015.

On January 5, 2015, the U.S. Government Accountability Office (GAO) denied a protest filed by Sierra Nevada Corp., of Louisville, Colorado, challenging the award of contracts to The Boeing Co., Space Exploration, of Houston, Texas, and to Space Exploration Technologies Corp. (SpaceX), of Hawthorne, California, by the National Aeronautics and Space Administration (NASA) for NASA’s Commercial Crew Transportation Capability Contract (CCtCap).  Sierra Nevada argued, among other things, that NASA’s evaluation departed from the solicitation’s stated evaluation and selection criteria by significantly elevating NASA’s stated “goal” of obtaining an integrated crew transportation system no later than the end of 2017, and by failing to put offerors on notice that the agency’s goal would be central to the evaluation and selection decision.

As explained in our decision, in this procurement, Sierra Nevada offered its Dream Chaser crew transportation system (a lifting body spacecraft), launched using United Launch Alliance’s Atlas 5 launch vehicle, and landed horizontally on normal runways.  Sierra Nevada’s price was $2.55 billion.

Boeing offered its CST-100 crew transportation system (a capsule spacecraft), also launched using United Launch Alliance’s Atlas 5 launch vehicle, and landed using parachute and airbag systems for hard-surface landings, or contingency water landings.  Boeing’s price was $3.01 billion.

SpaceX offered its Crew Dragon crew transportation system (also a capsule spacecraft), launched using SpaceX’s Falcon 9 launch vehicle, and landed using parachutes and propulsive soft landing systems for hard-surface landings, or contingency water landings.  SpaceX’s price was $1.75 billion.

In making its selection decision, NASA concluded that the proposals submitted by Boeing and SpaceX represented the best value to the government.  Specifically, NASA recognized Boeing’s higher price, but also considered Boeing’s proposal to be the strongest of all three proposals in terms of technical approach, management approach, and past performance, and to offer the crew transportation system with most utility and highest value to the government.  NASA also recognized several favorable features in the Sierra Nevada and SpaceX proposals, but ultimately concluded that SpaceX’s lower price made it a better value than the proposal submitted by Sierra Nevada.

GAO disagreed with Sierra Nevada’s arguments about NASA’s evaluation, and found no undue emphasis on NASA’s consideration of each offeror’s proposed schedule, and likelihood to achieve crew transportation system certification not later than 2017.  GAO also noted that, contrary to Sierra Nevada’s assertions, the RFP clearly advised offerors that their proposals would be evaluated against the goal of certification by the end of 2017.

Sierra Nevada also argued that NASA conducted an inadequate review of the realism of SpaceX’s price and overall financial resources, conducted a flawed and disparate evaluation of proposals under the mission suitability evaluation factor, and improperly evaluated the relevance of offerors’ past performance.  Based on our review of the issues, we concluded that these arguments were not supported by the evaluation record or by the terms of the solicitation.     

The GAO decision takes no position on the relative merits of these proposal approaches to NASA’s Commercial Crew Transportation Capability Contract.  Instead, GAO reviewed the conclusions reached by NASA to determine if they were reasonable, and consistent with the evaluation approach NASA set out in its solicitation.   

Because this protest decision contains proprietary and source selection sensitive information, release of the decision, at this point, is limited to NASA personnel and to outside counsel who have been admitted under the GAO protective order issued for this protest.  The parties have been directed to submit proposed redactions for the purpose of preparing a public version of the decision.  GAO expects to publish a public version of the decision as soon as possible; however, the release of a public decision may take a few weeks.  When the public version of the decision is available, it will be posted to our website, http://www.gao.gov (http://www.gao.gov)
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: IslandPlaya on 01/05/2015 04:36 pm
Basically. CST-1000 was chosen. SpaceX and DreamChaser were put against each other and SpaceX won on cost.
What a disgrace!
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Hauerg on 01/05/2015 04:44 pm
Ad CST-100: "and to offer the crew transportation system with most utility and highest value to the government".

Maybe somebody needs to be reminded that price != value.


OTOH I think it is better to go on now.
And thinking that the "other" result would have been "no Dragon" leads me down the WTF?!?-road.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: JBF on 01/05/2015 04:59 pm
Basically. CST-1000 was chosen. SpaceX and DreamChaser were put against each other and SpaceX won on cost.
What a disgrace!

I disagree, there is no disgrace.  NASA picked the CST-100 as top pick because in their view there was little risk that they wouldn't meet the schedule with an approved spacecraft.   
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: IslandPlaya on 01/05/2015 05:31 pm
Basically. CST-1000 was chosen. SpaceX and DreamChaser were put against each other and SpaceX won on cost.
What a disgrace!

I disagree, there is no disgrace.  NASA picked the CST-100 as top pick because in their view there was little risk that they wouldn't meet the schedule with an approved spacecraft.
pork.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: whitelancer64 on 01/05/2015 05:42 pm
Basically. CST-1000 was chosen. SpaceX and DreamChaser were put against each other and SpaceX won on cost.
What a disgrace!

I disagree, there is no disgrace.  NASA picked the CST-100 as top pick because in their view there was little risk that they wouldn't meet the schedule with an approved spacecraft.
pork.

not "pork."

the CST-100 won the award because Boeing's propsal resulted in minimal schedule risk for NASA.

"pork" is funding for a project put in legislation by a legislator, where that funding is specifically earmarked for a project in that legislator's district. in other words, "pork" is an appropriation of tax dollars that benefits a legislator's district. that's not the case here.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Jarnis on 01/05/2015 05:43 pm
Basically. CST-1000 was chosen. SpaceX and DreamChaser were put against each other and SpaceX won on cost.
What a disgrace!

I disagree, there is no disgrace.  NASA picked the CST-100 as top pick because in their view there was little risk that they wouldn't meet the schedule with an approved spacecraft.
pork.

More like excellent lobbying to disregard the cost.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Star One on 01/05/2015 07:08 pm
Basically. CST-1000 was chosen. SpaceX and DreamChaser were put against each other and SpaceX won on cost.
What a disgrace!

I disagree, there is no disgrace.  NASA picked the CST-100 as top pick because in their view there was little risk that they wouldn't meet the schedule with an approved spacecraft.
pork.

Not pork common sense. Reliability won out as it should.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: newpylong on 01/05/2015 07:31 pm
Basically. CST-1000 was chosen. SpaceX and DreamChaser were put against each other and SpaceX won on cost.
What a disgrace!

I disagree, there is no disgrace.  NASA picked the CST-100 as top pick because in their view there was little risk that they wouldn't meet the schedule with an approved spacecraft.
pork.

Unspeculated baloney.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: vt_hokie on 01/05/2015 07:31 pm
Another sad chapter in the long HL-20 saga.  Reusable lifting body shuttles will remain sci-fi for the early 21st century at least I guess (sigh)
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Alpha Control on 01/05/2015 07:59 pm
Another sad chapter in the long HL-20 saga.  Reusable lifting body shuttles will remain sci-fi for the early 21st century at least I guess (sigh)

I feel the same way, VT.  If I were SNC, I'd be trying to sell DC to the Japanese. I don't know how good a fit Dream Chaser is to the HII launch vehicle. But smart people can perform that evaluation.

Would JAXA want to finance the completion of DC, and become the owner of one or more crew-carrying vehicles? I don't know, but maybe a business case can be made for them to do it. Thoughts?
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: yg1968 on 01/05/2015 08:09 pm
Basically. CST-1000 was chosen. SpaceX and DreamChaser were put against each other and SpaceX won on cost.
What a disgrace!

I am not so sure, reading the selection statement on L2 gave me the impression that SpaceX edged Boeing overall because of its much lower price despite the fact that the CST-100 won on non-price factors.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Jim on 01/05/2015 08:15 pm

Would JAXA want to finance the completion of DC, and become the owner of one or more crew-carrying vehicles? I don't know, but maybe a business case can be made for them to do it. Thoughts?

No, for many reasons
a.  There are ITAR implications.
b.  JAXA would look to Japanese industry for services.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: yg1968 on 01/05/2015 08:20 pm

Would JAXA want to finance the completion of DC, and become the owner of one or more crew-carrying vehicles? I don't know, but maybe a business case can be made for them to do it. Thoughts?

No, for many reasons
a.  There are ITAR implications.
b.  JAXA would look to Japanese industry for services.

Jim,

Couldn't the ITAR implications be managed as is the case with other US payloads that are launched abroad?

I don't think that JAXA has the money for a crewed program. So collaborating with SNC could help them achieve their goal at a lower cost.

Incidentally, the collaboration agreement which was discussed by JAXA and SNC was for an uncrewed version of DC. 
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: dglow on 01/05/2015 08:45 pm
Basically. CST-1000 was chosen. SpaceX and DreamChaser were put against each other and SpaceX won on cost.
What a disgrace!

I am not so sure, reading the selection statement on L2 gave me the impression that SpaceX edged Boeing overall because of its much lower price despite the fact that the CST-100 won on non-price factors.

Hmm, I don't know... to me Gerst's tone toward SpaceX read like stern principal to troubled student. Boeing was the star pupil and varsity athlete.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: yg1968 on 01/05/2015 08:49 pm
Basically. CST-1000 was chosen. SpaceX and DreamChaser were put against each other and SpaceX won on cost.
What a disgrace!

I am not so sure, reading the selection statement on L2 gave me the impression that SpaceX edged Boeing overall because of its much lower price despite the fact that the CST-100 won on non-price factors.

Hmm, I don't know... to me Gerst's tone toward SpaceX read like stern principal to troubled student. Boeing was the star pupil and varsity athlete.

True but the conclusion gives the impression that SpaceX edged Boeing because of the importance of the price factor.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Steam Chaser on 01/05/2015 09:06 pm
I disagree, there is no disgrace.  NASA picked the CST-100 as top pick because in their view there was little risk that they wouldn't meet the schedule with an approved spacecraft.   

It looks to me like there is (and was at award time) essentially no chance CST-100 will meet the schedule, based on the price figures in the GAO statement, if I'm interpreting those figures correctly.  I'll combine these with a 2nd column with the maximum contract values NASA announced at the initial awards.  The values are in billions of dollars.

Sierra Nevada - 2.55
Boeing            - 3.01         4.2
SpaceX           - 1.75         2.6

Can I assume that the first column is the amount the companies bid, and the winners would receive from NASA, for initial development of the commercial crew systems?  The second column is the maximum contract award including initial development, optional "special studies" requested by NASA, and up to 6 operational flights.

If that is correct (I welcome corrections), Boeing got $3.01B for initial development.  To meet the 2017 date, they would need that money in years 2015-2017.  We know NASA commercial crew got $805M this year (and there was no prospect of getting much more than that at the time of the award).  So ... Boeing needs to get a total of about $2.2B in 2016 and 2017 to be done by 2017, or an average of $1.1B per year.  Does anyone think there was ever a chance that NASA will get enough commercial crew funding to satisfy that?  If this is correct, Boeing's bid never had a chance of being ready by 2017.  Don't forget that NASA also selected SpaceX which also needs commercial crew funding, NASA will need to use some funds for oversight, and NASA could request "special studies", all of which further dilute the amount Boeing could receive.

The Sierra Nevada bid was lower, so its schedule would suffer less from the budget problem I outlined above.  That is not to say that Sierra Nevada would be ready by 2017 either, since they do still suffer from the budget problem, and there could be other factors that could slow them (more difficult task, farther behind due to earlier "half award", etc).

Of course we already know NASA has now fallen back to 2018 instead of 2017.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Star One on 01/05/2015 09:07 pm
Basically. CST-1000 was chosen. SpaceX and DreamChaser were put against each other and SpaceX won on cost.
What a disgrace!

I disagree, there is no disgrace.  NASA picked the CST-100 as top pick because in their view there was little risk that they wouldn't meet the schedule with an approved spacecraft.
pork.

Not pork common sense. Reliability won out as it should.

You will do better questioning man rating Atlas 5 than the CST-100.
ULA don't seem to think this will be any great issue.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: IslandPlaya on 01/05/2015 09:09 pm
It will be impossible to man-rate a US launcher with a Russian engine. IMHO. Jim?
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: butters on 01/05/2015 09:13 pm
If ULA is supposed to get their launch vehicle certified by a certain date, then I'm sure that will happen on time. That date will not pass with people here wondering what happened with that certification that everybody said was supposed to be granted.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: QuantumG on 01/05/2015 09:14 pm
Boeing was the best choice because of the low schedule risk.. as we all know, Boeing has never had problems with meeting a schedule and they really need this contract. Yep, the government really made the best decision. If you don't agree, here's a statement from the government that says they have reviewed the matter and found no wrong-doing.


Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: IslandPlaya on 01/05/2015 09:48 pm
I would say Boeing are ace.
I know that QG will disagree with me no matter what.
Could any Russian engine power a man-rated stack?
I would say No.
Discuss.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: mkent on 01/05/2015 10:02 pm
It will be impossible to man-rate a US launcher with a Russian engine. IMHO. Jim?

Why do you say that?  Boeing and ULA have already taken the ground system (including the Atlas V) through CDR, and NASA has bought off on the design.  Those three entities apparently think it can be done.

DreamChaser would have used the same launch vehicle.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: IslandPlaya on 01/05/2015 10:04 pm
http://www.theguardian.com/world/2015/jan/04/us-russia-era-nuclear-rivalry
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Planetaryduality on 01/05/2015 10:13 pm
That Russian engine has been trouble free for all Atlas V flights, ULA already has a stockpile, and there are no indications that shipments will cease until the last engine that was ordered. Why would Atlas V be a bad choice?
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: mkent on 01/05/2015 10:22 pm
Boeing was the best choice because of the low schedule risk.. as we all know, Boeing has never had problems with meeting a schedule and they really need this contract. Yep, the government really made the best decision. If you don't agree, here's a statement from the government that says they have reviewed the matter and found no wrong-doing.

Your sarcastic tone is misguided.  Needing the contract is irrelevant, and Boeing has had far better schedule performance than the other two Commercial Crew contractors.

SpaceX was years late on Falcon 1 and Falcon 9, is years late on Falcon Heavy and DragonLab, and is almost a year behind on their last CCiCap milestones.

Sierra Nevada is running over a year and a half behind schedule on their milestones, and their schedule (had they maintained it) would have put them a year behind Boeing.  There was little realistic chance that they could have made up that time in the next three years when starting 2-1/2 years behind.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: OpsAnalyst on 01/05/2015 10:38 pm
Boeing was the best choice because of the low schedule risk.. as we all know, Boeing has never had problems with meeting a schedule and they really need this contract. Yep, the government really made the best decision. If you don't agree, here's a statement from the government that says they have reviewed the matter and found no wrong-doing.




Boeing's ahead on schedule - the only competitor to hit milestones on time - and you clearly don't understand (or don't care to) the role of the GAO - which has overturned findings favoring that very same Boeing in the past, most famously pertaining to a tanker worth a heck of a lot more than this contract. 
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: butters on 01/05/2015 10:38 pm
The irony of this schedule risk primacy is that, in all likelihood, NASA will be the one holding up the show in 2017-2018.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: QuantumG on 01/05/2015 10:45 pm
Boeing's ahead on schedule - the only competitor to hit milestones on time

Ya mean the incredibly underwhelming milestones they chose for themselves?

Quote from: OpsAnalyst
- and you clearly don't understand (or don't care to) the role of the GAO - which has overturned findings favoring that very same Boeing in the past, most famously pertaining to a tanker worth a heck of a lot more than this contract.

So what? The fact remains that the fox is guarding the hen house - the way it always is with government.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: ChrisWilson68 on 01/05/2015 11:17 pm
I don't think that JAXA has the money for a crewed program. So collaborating with SNC could help them achieve their goal at a lower cost.

If they want low cost and are willing to pay a U.S. company for a vehicle, they will let NASA fund the development of CST-100 and Dragon 2, then just buy one of those.  It would be much higher cost to fund both the development and production of Dream Chaser than to buy some units of CST-100 or Dragon 2 once they are already in production.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: mkent on 01/05/2015 11:49 pm
Boeing's ahead on schedule - the only competitor to hit milestones on time

Ya mean the incredibly underwhelming milestones they chose for themselves?

Underwhelming?  They completed CDR.  They are thus far the only contractor to do so.  That milestone is far, far greater than any other milestone in the CCiCap contract.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: QuantumG on 01/05/2015 11:55 pm
Boeing's ahead on schedule - the only competitor to hit milestones on time

Ya mean the incredibly underwhelming milestones they chose for themselves?

Underwhelming?

Underwhelming.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: ChrisWilson68 on 01/05/2015 11:55 pm
Boeing's ahead on schedule - the only competitor to hit milestones on time

Ya mean the incredibly underwhelming milestones they chose for themselves?

Underwhelming?  They completed CDR.  They are thus far the only contractor to do so.  That milestone is far, far greater than any other milestone in the CCiCap contract.

Personally, I'm more impressed by the pad abort and in-flight abort tests.  Flying actual hardware trumps having a meeting about it and deciding it will work.

SpaceX will get their own CDR passed too, but Boeing isn't going to do any abort tests.  Not impressive at all.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: QuantumG on 01/06/2015 12:02 am
SpaceX will get their own CDR passed too

M13A is already done.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: mkent on 01/06/2015 12:38 am

Personally, I'm more impressed by the pad abort and in-flight abort tests.  Flying actual hardware trumps having a meeting about it and deciding it will work.

The abort tests are important pieces of test hardware.  But it's test hardware, not production hardware.  The CDR is about passing from design to fabrication.  It's the second-most important milestone on an aerospace program.

So as to not re-cover old ground on this thread, I'd suggest that anyone interested see this post (http://forum.nasaspaceflight.com/index.php?topic=35717.msg1272734#msg1272734) and continue the discussion on that thread.

SpaceX will get their own CDR passed too, but Boeing isn't going to do any abort tests.  Not impressive at all.

You're not impressed with a contractor that, starting four years after another contractor, completed their design first?  To each his own, I guess.

More relevant to this thread: If you can't see how a contractor that hits every milestone on time during a given development program is rated a lower schedule risk by the customer than one that frequently misses milestones by years, I can't help you.  I would think it's obvious.  It must be obvious to NASA and GAO, as the protest was denied.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: OpsAnalyst on 01/06/2015 12:51 am
Boeing's ahead on schedule - the only competitor to hit milestones on time

Ya mean the incredibly underwhelming milestones they chose for themselves?

Quote from: OpsAnalyst
- and you clearly don't understand (or don't care to) the role of the GAO - which has overturned findings favoring that very same Boeing in the past, most famously pertaining to a tanker worth a heck of a lot more than this contract.

So what? The fact remains that the fox is guarding the hen house - the way it always is with government.


You didn't read what I wrote or didn't care to understand it.  In the case I cited, the GAO overturned the gov't. 

Snark is not particularly illuminating.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: ChrisWilson68 on 01/06/2015 12:52 am
SpaceX will get their own CDR passed too, but Boeing isn't going to do any abort tests.  Not impressive at all.

You're not impressed with a contractor that, starting four years after another contractor, completed their design first?  To each his own, I guess.

What I'm not impressed with is that Boeing is doing zero abort tests and SpaceX is doing two.  Which held their CDR first is a minor issue compared to that.

More relevant to this thread: If you can't see how a contractor that hits every milestone on time during a given development program is rated a lower schedule risk by the customer than one that frequently misses milestones by years, I can't help you.  I would think it's obvious.  It must be obvious to NASA and GAO, as the protest was denied.

That has already been answered upthread: doing less impressive things on schedule is not always as good as doing more impressive things but having a schedule slip.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: erioladastra on 01/06/2015 12:54 am


Maybe somebody needs to be reminded that price != value.


back at you - some people need to understand what value is.  From NASA's point of view, Boeing which thinks, works and acts like NASA that is a huge plus for them.  It removes a lot of the friction and frustration NASA has had with SpaceX.  I will not weigh in if this is right or not but to NASA that is HUGELY valuable.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: ChrisWilson68 on 01/06/2015 12:56 am
And as for engineering program management, let us know when you've done some.

Lets all try to avoid the ad hominem attacks, please.  If someone is claiming the reason we should believe him or her is his or her background, then it's valid to talk about that background.  If the person is claiming the reasoning presented stands on its own merits, attacking the person's background simply lowers the level of discussion and adds nothing useful.  Unless someone is explicitly mentioning his or her background, it's implied that the post's reasoning stands on its own.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: OpsAnalyst on 01/06/2015 12:59 am


Maybe somebody needs to be reminded that price != value.


back at you - some people need to understand what value is.  From NASA's point of view, Boeing which thinks, works and acts like NASA that is a huge plus for them.  It removes a lot of the friction and frustration NASA has had with SpaceX.  I will not weigh in if this is right or not but to NASA that is HUGELY valuable.

Right.  "Best value" does NOT equal price. 
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: erioladastra on 01/06/2015 12:59 am
Boeing's ahead on schedule - the only competitor to hit milestones on time

Ya mean the incredibly underwhelming milestones they chose for themselves?

Quote from: OpsAnalyst
- and you clearly don't understand (or don't care to) the role of the GAO - which has overturned findings favoring that very same Boeing in the past, most famously pertaining to a tanker worth a heck of a lot more than this contract.

So what? The fact remains that the fox is guarding the hen house - the way it always is with government.

First of all, they ALL chose their milestones.  If you found Boeing's to be underwhelming maybe it is their experience in picking REALISTIC goals.  That is what NASA wanted to see.  SpaceX and SNC have had trouble meeting their milestones on time or completely (first time pass through).  Second, you don't see a lot of the work not covered in milestones.  Doesn't mean other stuff is going on.  Capsules are not sexy - but they are practical.  Boeing was not trying to innovate like SpaceX - they decided to go for sure/steady.  I think most of the sour grapes people are feeling is that they are thinking with their hearts and not their heads.  SNC started CCiCAP waay behind.  They were given a smaller share which, when combined with unrealistic goals, got them further behind.  And they had some serious issues passing milestones. 
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: erioladastra on 01/06/2015 01:01 am
It will be impossible to man-rate a US launcher with a Russian engine. IMHO. Jim?

Should not be an issue.  Might be an issue down the road of obtaining them but there is no reason these engines can't be man rated.  Boeing and ULA are well on their way to this and the maker of the engine has never come up.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: OpsAnalyst on 01/06/2015 01:01 am
And as for engineering program management, let us know when you've done some.

Lets all try to avoid the ad hominem attacks, please.  If someone is claiming the reason we should believe him or her is his or her background, then it's valid to talk about that background.  If the person is claiming the reasoning presented stands on its own merits, attacking the person's background simply lowers the level of discussion and adds nothing useful.  Unless someone is explicitly mentioning his or her background, it's implied that the post's reasoning stands on its own.


I agree and apologize.  I modified the post and removed the comment.

Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Jim on 01/06/2015 01:04 am

Jim,

Couldn't the ITAR implications be managed as is the case with other US payloads that are launched abroad?

I don't think that JAXA has the money for a crewed program. So collaborating with SNC could help them achieve their goal at a lower cost.


Payloads that are launched abroad are still handled and managed by the US manufacturer.  Other countries don't directly deal with the spacecraft.

Not necessarily and still doesn't help their industry
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: erioladastra on 01/06/2015 01:04 am

Personally, I'm more impressed by the pad abort and in-flight abort tests.  Flying actual hardware trumps having a meeting about it and deciding it will work.

The abort tests are important pieces of test hardware.  But it's test hardware, not production hardware.  The CDR is about passing from design to fabrication.  It's the second-most important milestone on an aerospace program.

So as to not re-cover old ground on this thread, I'd suggest that anyone interested see this post (http://forum.nasaspaceflight.com/index.php?topic=35717.msg1272734#msg1272734) and continue the discussion on that thread.

SpaceX will get their own CDR passed too, but Boeing isn't going to do any abort tests.  Not impressive at all.

You're not impressed with a contractor that, starting four years after another contractor, completed their design first?  To each his own, I guess.

More relevant to this thread: If you can't see how a contractor that hits every milestone on time during a given development program is rated a lower schedule risk by the customer than one that frequently misses milestones by years, I can't help you.  I would think it's obvious.  It must be obvious to NASA and GAO, as the protest was denied.

Testing real hardware is a balance - you want the best fidelity for the lowest cost.  The amount of info you get out of an inflight abort is very small and when you consider the cost, it is not practical.  For inflight to be useful you need to do it at multiple speeds and that is not practical.  let's use some common sense here - look how much money NASA spent on abort capabilities for the shuttle and it was used how many times???  better to spend your money and focus on finding the Achilles heels!
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: butters on 01/06/2015 01:08 am
Maybe somebody needs to be reminded that price != value.
back at you - some people need to understand what value is.  From NASA's point of view, Boeing which thinks, works and acts like NASA that is a huge plus for them.  It removes a lot of the friction and frustration NASA has had with SpaceX.  I will not weigh in if this is right or not but to NASA that is HUGELY valuable.
Right.  "Best value" does NOT equal price.

But value is in the eye of the beholder, and basing a bid competition on a subjective measure like that basically boils down to the government chose the one(s) they liked the best. Maybe we should quit the pretense of objectivity altogether and just let the government go shopping like anybody else if that's what they're going to do anyway?
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: OpsAnalyst on 01/06/2015 01:13 am
In the case I cited, the GAO overturned the gov't. 

.. i.e., they found it wasn't in the best interests of the government. Ya see the problem here?

If only there was some sort of impartial system for resolving disputes...

First of all, they ALL chose their milestones.  If you found Boeing's to be underwhelming maybe it is their experience in picking REALISTIC goals.

Realistically underwhelming.

Quote from: erioladastra
That is what NASA wanted to see.

Ya don't say..


Re: GAO / tanker - no, that's not what they found.  You don't know what you're talking about. 

Re: "underwhelming".  To you.  With no insight into proposals, no insight into program planning, no knowledge of risk management approaches being employed, no idea of anything other than what's publicly published. 

Re: NASA. Well, they're the ones paying, aren't they?  They're the ones responsible to Congress for dates, program performance, etc.  They're the ones who have to manage programmatic risk - for more than one program.   Commercial crew is a means to a couple of ends - and the top priority is _not_ "fostering a commercial space industry". The first priority is providing for the health and wellbeing of the ISS and the people on it - a point that sometimes seems lost in these discussions.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: OpsAnalyst on 01/06/2015 01:14 am
Maybe somebody needs to be reminded that price != value.
back at you - some people need to understand what value is.  From NASA's point of view, Boeing which thinks, works and acts like NASA that is a huge plus for them.  It removes a lot of the friction and frustration NASA has had with SpaceX.  I will not weigh in if this is right or not but to NASA that is HUGELY valuable.
Right.  "Best value" does NOT equal price.

But value is in the eye of the beholder, and basing a bid competition on a subjective measure like that basically boils down to the government chose the one(s) they liked the best. Maybe we should quit the pretense of objectivity altogether and just let the government go shopping like anybody else if that's what they're going to do anyway?

What more objective measures would you propose?  And what is the basis of your objection to the gov't's actions?  Something that's not subjective, please.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: arachnitect on 01/06/2015 01:23 am
What I'm not impressed with is that Boeing is doing zero abort tests and SpaceX is doing two.  Which held their CDR first is a minor issue compared to that.

When the award was announced they said Boeing was doing Pad Abort in 2016, did that change?
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: yg1968 on 01/06/2015 01:33 am


Maybe somebody needs to be reminded that price != value.


back at you - some people need to understand what value is.  From NASA's point of view, Boeing which thinks, works and acts like NASA that is a huge plus for them.  It removes a lot of the friction and frustration NASA has had with SpaceX.  I will not weigh in if this is right or not but to NASA that is HUGELY valuable.

There was a price factor which was the most important factor. Value was not supposed to be a factor. But you essentially summarized the selection statement in one paragraph. NASA likes the way Boeing does things. I got the impression by reading the selection statement that NASA didn't care much about price. It seems that only SpaceX cares about price. 
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: mkent on 01/06/2015 01:33 am
What I'm not impressed with is that Boeing is doing zero abort tests and SpaceX is doing two.

Boeing is doing an abort test.  It is just doing that test under CCtCap, not CCiCap.

Which held their CDR first is a minor issue compared to that.

This is backwards.  The CDR is the gateway between design and fabrication.  It's the second-most important milestone on an aerospace program after first flight (which is the gateway between fabrication and flight test).  The abort tests are just two tests among many.

Why single them out?  Why not single out the landing tests, which Boeing has completed, Sierra has had one test that ended badly, and SpaceX hasn't even started?  Why not the software tests?  Or the avionics tests?  Or the pilot-in-the-loop tests?  Or the mission control simulations?  Those tests are just as important as the abort tests.  Arguably they're more important, as those things will be used on every flight, not just the one in a hundred that has an abort.

Could it be because that's the one area that SpaceX has a clear lead based on publicly available information?
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: mkent on 01/06/2015 01:38 am
If I were SNC, I'd be trying to sell DC to the Japanese. I don't know how good a fit Dream Chaser is to the HII launch vehicle. But smart people can perform that evaluation.

Would JAXA want to finance the completion of DC, and become the owner of one or more crew-carrying vehicles? I don't know, but maybe a business case can be made for them to do it. Thoughts?

Highly, highly unlikely.  Sierra Nevada's bid was apparently $2.55 billion just for development.  There is almost no chance that JAXA, ESA, or any other government agency is going to be sending that kind of money over to America for a prestige project instead of spending it at home.  It negates the main reason why those projects are done in the first place.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: yg1968 on 01/06/2015 01:42 am
If I were SNC, I'd be trying to sell DC to the Japanese. I don't know how good a fit Dream Chaser is to the HII launch vehicle. But smart people can perform that evaluation.

Would JAXA want to finance the completion of DC, and become the owner of one or more crew-carrying vehicles? I don't know, but maybe a business case can be made for them to do it. Thoughts?

Highly, highly unlikely.  Sierra Nevada's bid was apparently $2.55 billion just for development.  There is almost no chance that JAXA, ESA, or any other government agency is going to be sending that kind of money over to America for a prestige project instead of spending it at home.  It negates the main reason why those projects are done in the first place.

The price of $2.55B for SNC's proposals includes an uncrewed test flight, at least one crewed demo flight to the ISS and six post certification missions. I suspect that just finishing the development of the spacecraft would likely be less than half of that amount.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: butters on 01/06/2015 01:50 am
Maybe somebody needs to be reminded that price != value.
back at you - some people need to understand what value is.  From NASA's point of view, Boeing which thinks, works and acts like NASA that is a huge plus for them.  It removes a lot of the friction and frustration NASA has had with SpaceX.  I will not weigh in if this is right or not but to NASA that is HUGELY valuable.
Right.  "Best value" does NOT equal price.

But value is in the eye of the beholder, and basing a bid competition on a subjective measure like that basically boils down to the government chose the one(s) they liked the best. Maybe we should quit the pretense of objectivity altogether and just let the government go shopping like anybody else if that's what they're going to do anyway?

What more objective measures would you propose?  And what is the basis of your objection to the gov't's actions?  Something that's not subjective, please.

I object to pretense of objectivity in government procurement. I think NASA made a reasonable selection, but let's not pretend it was based on scores in three categories with price worth twice the others. When we pretend there are rules, stakeholders get upset when it seems like they aren't being followed or they aren't being interpreted properly.

The government wastes a lot of resources on providing legal cover for the purchases they're going to make anyway. It doesn't prevent fraud. It doesn't prevent boondoggles. It just makes everything more expensive, more contentious, and more litigious.

NASA selected the bids they thought were best, and nobody can prove otherwise. That's all the legal cover that really matters.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: yg1968 on 01/06/2015 01:52 am
What I'm not impressed with is that Boeing is doing zero abort tests and SpaceX is doing two.

Boeing is doing an abort test.  It is just doing that test under CCtCap, not CCiCap.

Boeing isn't doing an inflight abort test for CCtCap per the selection statement.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: robertross on 01/06/2015 02:08 am
At the end of the day, I fear a great number of good people will be out looking for work, at a time I feel is most disconcerting.

Dream Chaser had some incredible potential for ISS use, and wish them all the best in trying to find a place for her - in her current configuration or the scaled-down one being considered.

All the best to SNC, their workers, and their families in the weeks ahead.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: mkent on 01/06/2015 02:22 am
What I'm not impressed with is that Boeing is doing zero abort tests and SpaceX is doing two.

Boeing is doing an abort test.  It is just doing that test under CCtCap, not CCiCap.

Boeing isn't doing an inflight abort test for CCtCap per the selection statement.

I think you're right, but I think they are doing a pad abort test, which would be one of the two abort tests to which ChrisWilson68 was referring.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: whitelancer64 on 01/06/2015 02:29 am
What I'm not impressed with is that Boeing is doing zero abort tests and SpaceX is doing two.

Boeing is doing an abort test.  It is just doing that test under CCtCap, not CCiCap.

Boeing isn't doing an inflight abort test for CCtCap per the selection statement.

I think you're right, but I think they are doing a pad abort test, which would be one of the two abort tests to which ChrisWilson68 was referring.

"Boeing will immediately begin manufacturing three CST-100 structural test articles at the Commercial Crew Processing Facility pending NASA award. These test articles will be used in the pad abort test in 2016, first uncrewed flight in early 2017, as well as the first crewed flight to the ISS in mid-2017."

http://www.boeing.com/boeing/defense-space/space/ccts/index.page (http://www.boeing.com/boeing/defense-space/space/ccts/index.page)
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: QuantumG on 01/06/2015 02:33 am
"Boeing will immediately begin manufacturing three CST-100 structural test articles at the Commercial Crew Processing Facility pending NASA award. These test articles will be used in the pad abort test in 2016, first uncrewed flight in early 2017, as well as the first crewed flight to the ISS in mid-2017."

Demonstrating that they plan to learn nothing from the pad abort test.

Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: mkent on 01/06/2015 02:36 am
The price of $2.55B for SNC's proposals includes an uncrewed test flight, at least one crewed demo flight to the ISS and six post certification missions. I suspect that just finishing the development of the spacecraft would likely be less than half of that amount.

I don't think so.  The $3.3 billion figure Sierra Nevada disclosed during their protest press release includes all of those things.

At the time I posted that, I thought that the $2.55 billion figure was to finish the development and perform the two test flights.  However, I now think that the $2.55 billion figure is just the guaranteed contract minimum (the difference being the two guaranteed operational flights).  That would put the development cost at $1.95 billion.

See this post (http://forum.nasaspaceflight.com/index.php?topic=35680.45) and the two posts prior for a crude cost analysis.

Regardless, that's going to be way more than any foreign government is going to throw across the pond for a prestige space program such as this.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: dglow on 01/06/2015 02:39 am
"Boeing will immediately begin manufacturing three CST-100 structural test articles at the Commercial Crew Processing Facility pending NASA award. These test articles will be used in the pad abort test in 2016, first uncrewed flight in early 2017, as well as the first crewed flight to the ISS in mid-2017."

Demonstrating that they plan to learn nothing from the pad abort test.

Take your point, QG, but it's a bit unfair. Boeing will bend steel and validate their simulations with this abort test. Should their sims prove invalid... it'll be a costly error.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: yg1968 on 01/06/2015 02:52 am
The price of $2.55B for SNC's proposals includes an uncrewed test flight, at least one crewed demo flight to the ISS and six post certification missions. I suspect that just finishing the development of the spacecraft would likely be less than half of that amount.

I don't think so.  The $3.3 billion figure Sierra Nevada disclosed during their protest press release includes all of those things.

At the time I posted that, I thought that the $2.55 billion figure was to finish the development and perform the two test flights.  However, I now think that the $2.55 billion figure is just the guaranteed contract minimum (the difference being the two guaranteed operational flights).  That would put the development cost at $1.95 billion.

See this post (http://forum.nasaspaceflight.com/index.php?topic=35680.45) and the two posts prior for a crude cost analysis.

Regardless, that's going to be way more than any foreign government is going to throw across the pond for a prestige space program such as this.

Sorry, I meant that that the $3.3B included all of these test flights and post certification missions.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Robotbeat on 01/06/2015 03:32 am
I am disappointed that Dream Chaser won't likely be flying anytime soon, and I definitely feel bad for the people who have lost their jobs due to this decision, but on the bright side, I'm glad that the majority of the legal crap is done with.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: yg1968 on 01/06/2015 03:35 am
I am disappointed that Dream Chaser won't likely be flying anytime soon, and I definitely feel bad for the people who have lost their jobs due to this decision, but on the bright side, I'm glad that the majority of the legal crap is done with.

The best hope for DC is now the scaled-DC. Hopefully, we will hear more about this soon. Stratolaunch and SNC may have been waiting for the outcome of the protest before announcing anything. 
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Jim on 01/06/2015 08:47 am
"Boeing will immediately begin manufacturing three CST-100 structural test articles at the Commercial Crew Processing Facility pending NASA award. These test articles will be used in the pad abort test in 2016, first uncrewed flight in early 2017, as well as the first crewed flight to the ISS in mid-2017."

Demonstrating that they plan to learn nothing from the pad abort test.


 ::) Pad abort test is not structural test.  It is a system integration test. 
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: sublimemarsupial on 01/06/2015 10:03 am
"Boeing will immediately begin manufacturing three CST-100 structural test articles at the Commercial Crew Processing Facility pending NASA award. These test articles will be used in the pad abort test in 2016, first uncrewed flight in early 2017, as well as the first crewed flight to the ISS in mid-2017."

Demonstrating that they plan to learn nothing from the pad abort test.


 ::) Pad abort test is not structural test.  It is a system integration test.

.... meaning there is nothing to be learned from a systems integration test?
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Jim on 01/06/2015 10:08 am
::) Pad abort test is not structural test.  It is a system integration test.

.... meaning there is nothing to be learned from a systems integration test?

no, that is what they are testing.  The structure can and is tested separately.

edit/Lar: fix quotes
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: sublimemarsupial on 01/06/2015 10:32 am
::) Pad abort test is not structural test.  It is a system integration test.

.... meaning there is nothing to be learned from a systems integration test?

no, that is what they are testing.  The structure can and is tested separately.


You can learn things from a systems integration test that require changes to the structure.


edit/Lar: fix quotes
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Jim on 01/06/2015 10:51 am
You can learn things from a systems integration test that require changes to the structure.

More likely it will be secondary structure.  The primary structure shouldn't have issues, the loads tests should envelope and potential flight loads with margin.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Rocket Science on 01/06/2015 03:55 pm
So we still may see another ALT test this year with the aero data that can be applied to cargo-only DC or Mini DC...
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: newpylong on 01/06/2015 06:14 pm
Boeing's ahead on schedule - the only competitor to hit milestones on time

Ya mean the incredibly underwhelming milestones they chose for themselves?

Quote from: OpsAnalyst
- and you clearly don't understand (or don't care to) the role of the GAO - which has overturned findings favoring that very same Boeing in the past, most famously pertaining to a tanker worth a heck of a lot more than this contract.

So what? The fact remains that the fox is guarding the hen house - the way it always is with government.

Be sure to let them know that a space aficionado and armchair aerospace engineer from Australia is underwhelmed by their milestones - perhaps they will change the development plan.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: yg1968 on 01/06/2015 06:53 pm
Boeing's ahead on schedule - the only competitor to hit milestones on time

Ya mean the incredibly underwhelming milestones they chose for themselves?

Quote from: OpsAnalyst
- and you clearly don't understand (or don't care to) the role of the GAO - which has overturned findings favoring that very same Boeing in the past, most famously pertaining to a tanker worth a heck of a lot more than this contract.

So what? The fact remains that the fox is guarding the hen house - the way it always is with government.

Be sure to let them know that a space aficionado and armchair aerospace engineer from Australia is underwhelmed by their milestones - perhaps they will change the development plan.

Why would Boeing change their underwhelming milestones? It's like setting goals for yourselves for the year that you are sure to meet just by showing up at work.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: redliox on 01/06/2015 07:12 pm
Since the Dream Chaser is out of the commercial running, at least with American launch pads, what is their next likely move aside from layoffs?

If they are going to turn to international partners, how well would Dream Chaser fit with the rockets of ESA or JAXA?  I would think the Ariane 5 would fit well given its roots were tied to the ill-fated Heremes, and even JAXA hoped to have a shuttle-shaped unmanned vehicle on it's rockets.

I do hope they have a viable "plan B," as they honestly have a good idea.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: rayleighscatter on 01/06/2015 08:29 pm
Since the Dream Chaser is out of the commercial running, at least with American launch pads, what is their next likely move aside from layoffs?
That's not entirely true. They still have their commercial cargo proposal out right now.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: obi-wan on 01/06/2015 09:06 pm
http://www.gao.gov/press/pr_statement_sierra_nevada_bid_protest.htm (http://www.gao.gov/press/pr_statement_sierra_nevada_bid_protest.htm)

Press Release
Statement on Sierra Nevada Bid Protest Decision

[snip] Specifically, NASA recognized Boeing’s higher price, but also considered Boeing’s proposal to... offer the crew transportation system with most utility and highest value to the government. [snip]

Okay, the one question I still have from this is, what are the specifics that lead to this conclusion? Gerst said it and it's repeated here that they think CST-100 is a more capable spacecraft than Dragon 2. What are the salient features that they're thinking of? It's larger in volume, but it's also heavier, and the packing efficiency of the 32.5deg half-angle cone of CST-100 is a lot less than the 15deg half-angle of the Dragon. The docking systems are functionally identical, so you can't get larger cargo packages through one compared to the other. Does CST-100 have better orbital maneuvering capability? Were they super-impressed with the 787 Dreamliner-style interior mockup? Do they prefer the Boeing LAS to the SpaceX system? Is there any reasonable expectation that we might someday get some rationale for this preference?
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: llanitedave on 01/06/2015 11:44 pm
Is there a difference in ISS reboost ability?
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: ChrisWilson68 on 01/07/2015 08:52 am
http://www.gao.gov/press/pr_statement_sierra_nevada_bid_protest.htm (http://www.gao.gov/press/pr_statement_sierra_nevada_bid_protest.htm)

Press Release
Statement on Sierra Nevada Bid Protest Decision

[snip] Specifically, NASA recognized Boeing’s higher price, but also considered Boeing’s proposal to... offer the crew transportation system with most utility and highest value to the government. [snip]

Okay, the one question I still have from this is, what are the specifics that lead to this conclusion? Gerst said it and it's repeated here that they think CST-100 is a more capable spacecraft than Dragon 2. What are the salient features that they're thinking of? It's larger in volume, but it's also heavier, and the packing efficiency of the 32.5deg half-angle cone of CST-100 is a lot less than the 15deg half-angle of the Dragon. The docking systems are functionally identical, so you can't get larger cargo packages through one compared to the other. Does CST-100 have better orbital maneuvering capability? Were they super-impressed with the 787 Dreamliner-style interior mockup? Do they prefer the Boeing LAS to the SpaceX system? Is there any reasonable expectation that we might someday get some rationale for this preference?

NASA values doing things the NASA way.  Boeing was more willing to do things the NASA way than SpaceX.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Rocket Science on 01/07/2015 10:24 am
This is a Dream Chaser thread, can we take the SpaceX vs. Boeing talk elsewhere please...
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Patchouli on 01/16/2015 02:08 am
One crazy idea I just had maybe SNC should look into partnering with Blue Origin.

BE has a lot of work going on in LV development and got ULAs backing for engine development but they were lagging on an orbital vehicle.
DC is pretty far along and SNC has a lot of experience in space systems which BE lacks.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: ChrisWilson68 on 01/16/2015 02:32 am
One crazy idea I just had maybe SNC should look into partnering with Blue Origin.

BE has a lot of work going on in LV development and got ULAs backing for engine development but they were lagging on an orbital vehicle.
DC is pretty far along and SNC has a lot of experience in space systems which BE lacks.

Blue Origin has been working on their own spacecraft.  The spacecraft itself seems to be a lot of what interests Bezos.  I can't see him being interested in siphoning funds off that to pay for Dream Chaser instead.

And, really, I don't think it's accurate to say Dream Chaser is pretty far along.  Look at how much has been spent on it and compare that to the SNC bid for CCtCap.  Only a small fraction of the needed money has been spent on Dream Chaser.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Todd Martin on 02/04/2015 01:17 am
Critics of the idea of Dreamchaser use by the European Union say:  1) ESA has a strong bias to using European companies for projects, 2) It would be cheaper for ESA to use CST-100 or DragonRider, 3) ESA already has a barter arrangement with NASA for rides to ISS.

These points do not include:

1) SNC can partner with European companies.  Many major European spacecraft have had U.S. partners.  SNC has been actively building a coalition to get buy in.

2) Neither CST-100 nor DragonRider have been qualified to launch on a European launch vehicle.  Neither Boeing nor SpaceX are likely to go out of their way to do so.  Boeing has a vested interest in the success of ULA and the Atlas V.  SpaceX has a vested interest in the success of Falcon 9.  SNC suffers no conflict of interest and is motivated to bring their vehicle online.  They have already demonstrated a willingness to explore alternative launch vehicles.   

3) Here's the kicker.  What if ESA wants to visit the Chinese space station?  It would be politically impossible for ESA to launch from American soil to the Chinese station.  That leaves paying the Russians or the Chinese for a seat.  That's 100% money going out the EU.  A Dreamchaser launch from EU soil using an EU launcher and with EU companies partnered in DC now has all the arguments in favor of DC use as opposed to the naysayers. 

DC4Science is another example where the NASA barter arrangement for travel to ISS doesn't apply.  ISS has challenges in delay & red-tape getting an experiment approved for flight.  I've been frustrated that VASIMIR still hasn't flown.  DC4Science can allow for orbital science experiments without the barriers inherent in ISS use.

The arguments from the critics have merit, and SNC has some hard work ahead of them to close the case, but determination and persistence go a long way.  I'm rooting for them and believe they can do it.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: ChrisWilson68 on 02/04/2015 02:15 am
Critics of the idea of Dreamchaser use by the European Union say:  1) ESA has a strong bias to using European companies for projects, 2) It would be cheaper for ESA to use CST-100 or DragonRider, 3) ESA already has a barter arrangement with NASA for rides to ISS.

These points do not include:

1) SNC can partner with European companies.  Many major European spacecraft have had U.S. partners.  SNC has been actively building a coalition to get buy in.

Sure, there are joint, U.S.-European space projects.  But they're always part of carefully-constructed arrangements to make sure the amount of money spent in Europe is exactly the amount Europe contributes and the amount spent in the U.S. is exactly the amount spent by the U.S.

If the U.S. government isn't contributing to a joint project, no money for it will go to a U.S. company.  And the U.S. government won't be contributing money to any joint projects with Dream Chaser, so no money will be spent by Europe on it either.

2) Neither CST-100 nor DragonRider have been qualified to launch on a European launch vehicle.

Neither is Dream Chaser.

Neither Boeing nor SpaceX are likely to go out of their way to do so.  Boeing has a vested interest in the success of ULA and the Atlas V.  SpaceX has a vested interest in the success of Falcon 9.  SNC suffers no conflict of interest and is motivated to bring their vehicle online.  They have already demonstrated a willingness to explore alternative launch vehicles.

Europe has shown no willingness to spend any money on any American crew vehicle at all.  That's why Boeing and SpaceX haven't pursued it.  Of course if Europe said they were going to spend a billion dollars on it, Boeing and SpaceX would be crawling all over each other for that business.  SNC is the only one making noise about it because they're the only ones with no other prospects at all.

3) Here's the kicker.  What if ESA wants to visit the Chinese space station?  It would be politically impossible for ESA to launch from American soil to the Chinese station.  That leaves paying the Russians or the Chinese for a seat.  That's 100% money going out the EU.  A Dreamchaser launch from EU soil using an EU launcher and with EU companies partnered in DC now has all the arguments in favor of DC use as opposed to the naysayers.

Dragon and CST-100 could be adapted to fly on a European launch vehicle as easily as Dream Chaser.  More easily, actually, since they are simpler shapes and don't have the aerodynamic complexity of Dream Chaser.  And, of course, they will already be developed.  It's much easier to adapt a vehicle that exists than one that doesn't yet exist.

Anyway, Dream Chaser, Dragon, and CST-100 all have ITAR restrictions, so they couldn't be flown to a Chinese space station without U.S. government permission anyway, no matter what the launch vehicle.  If Europe wants to get out from under U.S. government restrictions, Dream Chaser won't help them.

DC4Science is another example where the NASA barter arrangement for travel to ISS doesn't apply.  ISS has challenges in delay & red-tape getting an experiment approved for flight.  I've been frustrated that VASIMIR still hasn't flown.  DC4Science can allow for orbital science experiments without the barriers inherent in ISS use.

SpaceX has exactly the same program.  It's called DragonLab, and it uses Dragon 1, so it already exists.  SpaceX doesn't seem to have had much luck finding customers for it.  So why would Dream Chaser for Science have any better luck finding customers when it would cost billions to even get it flying?

The arguments from the critics have merit, and SNC has some hard work ahead of them to close the case, but determination and persistence go a long way.  I'm rooting for them and believe they can do it.

It would be great if there were a huge market for travel to and from orbit.  I really wish there were.  Then it could support three different providers.  The current market is so tiny it can't really support even the two that already have their development funded.

Ironically, SpaceX is probably Dream Chaser's best chance of being revived again someday.  SpaceX is the only company that has a realistic chance of greatly reducing launch costs.  If they manage that, the market will grow enormously, and at that point Dream Chaser can come back to life and join the competition for market share.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Jim on 02/04/2015 02:26 am

3) Here's the kicker.  What if ESA wants to visit the Chinese space station?  It would be politically impossible for ESA to launch from American soil to the Chinese station.  That leaves paying the Russians or the Chinese for a seat.  That's 100% money going out the EU.  A Dreamchaser launch from EU soil using an EU launcher and with EU companies partnered in DC now has all the arguments in favor of DC use as opposed to the naysayers. 


Nope, since DC is American, it would be politically impossible for ESA to use it to go to a Chinese station.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Mike Harris-Stone on 02/04/2015 03:27 am
Sure, there are joint, U.S.-European space projects.  But they're always part of carefully-constructed arrangements to make sure the amount of money spent in Europe is exactly the amount Europe contributes and the amount spent in the U.S. is exactly the amount spent by the U.S.

Germany has already spent money on it.  (At least in the form of a study)
http://www.spaceref.com/news/viewpr.html?pid=44970 (http://www.spaceref.com/news/viewpr.html?pid=44970)

And this is still ongoing.  Don't forget that SNC is a large, very successful, privately held company, not a start up.  What they need far more than development funds are customers for their vehicle once its finished.  Maybe they are finding some...we will see.

Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: ChrisWilson68 on 02/04/2015 03:57 am
Sure, there are joint, U.S.-European space projects.  But they're always part of carefully-constructed arrangements to make sure the amount of money spent in Europe is exactly the amount Europe contributes and the amount spent in the U.S. is exactly the amount spent by the U.S.

Germany has already spent money on it.  (At least in the form of a study)
http://www.spaceref.com/news/viewpr.html?pid=44970 (http://www.spaceref.com/news/viewpr.html?pid=44970)

The money they spent on the study was paid to a German organization.  100% paid for by Germany, 100% spent in Germany.  Which is exactly my point.

And this is still ongoing.  Don't forget that SNC is a large, very successful, privately held company, not a start up.

ATK is a large, successful company too.  When Ares I was cancelled, they sounded just like SNC does now with Ares I rebranded as Liberty.  They tried to get NASA to pay for it, and they touted all sorts of opportunities from all sorts of potential customers.  They promised development would continue with private funding.  How did that work out?

What they need far more than development funds are customers for their vehicle once its finished.  Maybe they are finding some...we will see.

They need customers willing to pay enough to cover both the operational costs and the development costs.  And they're competing against not just one but two competitors with vehicles whose development costs are being paid for by NASA.  The idea they can find customers willing to pay enough is fantasy, at least until the market changes drastically.

Even Dragon 2 and CST-100 can't find customers outside NASA, and they already have their development costs covered.  And don't tell me about Bigelow, because Bigelow can't find any customers of its own, and they've already been partnering with CST-100 and Dragon, so if a miracle happens and Bigelow does find customers, it will only help CST-100 and/or Dragon.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Mike Harris-Stone on 02/04/2015 08:11 pm
Sure, there are joint, U.S.-European space projects.  But they're always part of carefully-constructed arrangements to make sure the amount of money spent in Europe is exactly the amount Europe contributes and the amount spent in the U.S. is exactly the amount spent by the U.S.

Germany has already spent money on it.  (At least in the form of a study)
http://www.spaceref.com/news/viewpr.html?pid=44970 (http://www.spaceref.com/news/viewpr.html?pid=44970)

The money they spent on the study was paid to a German organization.  100% paid for by Germany, 100% spent in Germany.  Which is exactly my point.

So you think the whole thing was some kind of economic exercise whereby Germans paid Germans with absolutely no interest at all in the American vehicle they were studying?  Otherwise I don't get the point.

And this is still ongoing.  Don't forget that SNC is a large, very successful, privately held company, not a start up.

ATK is a large, successful company too.  When Ares I was cancelled, they sounded just like SNC does now with Ares I rebranded as Liberty.  They tried to get NASA to pay for it, and they touted all sorts of opportunities from all sorts of potential customers.  They promised development would continue with private funding.  How did that work out?



I watched that too.  Liberty was a very different kind of vehicle.  SNC is very different.  For one, it would almost certainly launch on a European launch vehicle.  For pete's sack, SNC has agreements with both Germany and JAXA.  Even if they ultimately come to nothing, they've already gone a lot farther.


What they need far more than development funds are customers for their vehicle once its finished.  Maybe they are finding some...we will see.

They need customers willing to pay enough to cover both the operational costs and the development costs.  And they're competing against not just one but two competitors with vehicles whose development costs are being paid for by NASA.  The idea they can find customers willing to pay enough is fantasy, at least until the market changes drastically.

Even Dragon 2 and CST-100 can't find customers outside NASA, and they already have their development costs covered.  And don't tell me about Bigelow, because Bigelow can't find any customers of its own, and they've already been partnering with CST-100 and Dragon, so if a miracle happens and Bigelow does find customers, it will only help CST-100 and/or Dragon.


The people who run SNC don't live in a fantasy world.  They build real hardware that is in use as you read this on the surface of Mars and other places.  They are the kind of entrepreneurs who give the U.S. it's world wide place in Aerospace technology.  And they clearly have not put all their eggs in the NASA\Commercial crew basket.  SNC clearly anticipated that NASA would not necessarily pay their costs.  Why broker international agreements and also book a launch vehicle independently of NASA BEFORE the decision on which companies would be selected to continue Commercial Crew if everything depended on that?  They are running a risk, sure.  But based on these kind of facts, I think it's pretty safe to infer they have the means to continue to a certain point.

However, no business can make a serious investment like this unless they have a potential market.  SNC seems like they might be developing one, which would be excellent news for commercial space and space in general.

Part of the vision of Dreamchaser is certainly operations beyond the life of the ISS which is I think what has the Germans, etc. keenly interested.  CST-100, Dragon and Dreamchaser are not apples to apples products.  They have their individual strengths and weaknesses.  Dreamchaser may appeal to Europe, and may also be more flexible to what Europe wants, than either Dragon or CST-100.

The future will tell...
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: ChrisWilson68 on 02/04/2015 11:21 pm
Sure, there are joint, U.S.-European space projects.  But they're always part of carefully-constructed arrangements to make sure the amount of money spent in Europe is exactly the amount Europe contributes and the amount spent in the U.S. is exactly the amount spent by the U.S.

Germany has already spent money on it.  (At least in the form of a study)
http://www.spaceref.com/news/viewpr.html?pid=44970 (http://www.spaceref.com/news/viewpr.html?pid=44970)

The money they spent on the study was paid to a German organization.  100% paid for by Germany, 100% spent in Germany.  Which is exactly my point.

So you think the whole thing was some kind of economic exercise whereby Germans paid Germans with absolutely no interest at all in the American vehicle they were studying?  Otherwise I don't get the point.

No, I'm not saying that they had no interest in the American vehicle.  I'm saying they have no interest in paying European tax dollars to develop an American vehicle.

Europe has no problem doing join development.  They do barter deals where they work on parts of the ISS and the service module for Orion in return for getting to participate.  But their financial contribution is always spent in Europe.

It's not just that.  Even within Europe, the money is spent in each country according to how much of the ESA budget that country contributes.  Germany wouldn't even fund a French vehicle, and they're part of the EU, let alone an American vehicle.

And the fact that the money for the study was spent in Europe just underlines that point.


What they need far more than development funds are customers for their vehicle once its finished.  Maybe they are finding some...we will see.

They need customers willing to pay enough to cover both the operational costs and the development costs.  And they're competing against not just one but two competitors with vehicles whose development costs are being paid for by NASA.  The idea they can find customers willing to pay enough is fantasy, at least until the market changes drastically.

Even Dragon 2 and CST-100 can't find customers outside NASA, and they already have their development costs covered.  And don't tell me about Bigelow, because Bigelow can't find any customers of its own, and they've already been partnering with CST-100 and Dragon, so if a miracle happens and Bigelow does find customers, it will only help CST-100 and/or Dragon.

The people who run SNC don't live in a fantasy world.  They build real hardware that is in use as you read this on the surface of Mars and other places.  They are the kind of entrepreneurs who give the U.S. it's world wide place in Aerospace technology.  And they clearly have not put all their eggs in the NASA\Commercial crew basket.  SNC clearly anticipated that NASA would not necessarily pay their costs.  Why broker international agreements and also book a launch vehicle independently of NASA BEFORE the decision on which companies would be selected to continue Commercial Crew if everything depended on that?  They are running a risk, sure.  But based on these kind of facts, I think it's pretty safe to infer they have the means to continue to a certain point.

I completely disagree.  The "agreements" with other countries are pretty meaningless.  They don't commit anyone to pay SNC for anything.  Companies sign these kinds of agreements all the time, and they're mostly for PR purposes.  At best, they essentially say, "if we decide to someday work together, here are some ways we'll do it".

The governments are happy to sign agreements like this because it costs them nothing and keeps their options open for the future.

However, no business can make a serious investment like this unless they have a potential market.  SNC seems like they might be developing one, which would be excellent news for commercial space and space in general.

I don't see any evidence they're actually creating any demand -- that is, convincing anyone with the means to do so to buy from them at the prices they would need to make the program economically feasible.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Rocket Science on 02/05/2015 12:35 am
Well that’s it then according to the gospel of CW... We should notify SNC to cease and desist all development of Dream Chaser and negotiations thereof... Perhaps we should lock all the DC threads then and discuss the “one and only” vehicle in the universe...
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: ChrisWilson68 on 02/05/2015 12:44 am
Well that’s it then according to the gospel of CW... We should notify SNC to cease and desist all development of Dream Chaser and negotiations thereof... Perhaps we should lock all the DC threads then and discuss the “one and only” vehicle in the universe...

Why the need for sarcasm?  I state my opinions, you state your opinions.  It's nothing personal.  If I think the chances of Dream Chaser getting European funding are extremely low, why shouldn't I post that?

Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Mike Harris-Stone on 02/05/2015 03:35 am
Well that’s it then according to the gospel of CW... We should notify SNC to cease and desist all development of Dream Chaser and negotiations thereof... Perhaps we should lock all the DC threads then and discuss the “one and only” vehicle in the universe...

Why the need for sarcasm?  I state my opinions, you state your opinions.  It's nothing personal.  If I think the chances of Dream Chaser getting European funding are extremely low, why shouldn't I post that?

Not wanting to beat this to death...but I did have a little more to add.

I agree with your analysis of how Europe spends money.  And I wasn't over optimistic about the agreements either.  But I do like to watch closely what is going on...at least as much as that's even possible via the internet and here is what I've seen:

1.  A major German newspaper printed a story a few days ago about SNC and the German Space Agency looking into DC landing sites in Germany.  Several other papers picked the story up.
2. The announcement indicates there is more coming after the study.  This really perked up my antenna.
3. The new head of ESA is the same person who was behind the study with SNC and also, from what I read, ESA getting involved in the Orion Service Module.

Do I think ESA is going to pump money into Dreamchaser development costs?  Not necessarily, no.  But unlike you, I'm not convinced that is necessary for DC to happen.  It may well be that SNC has enough money on their own to get DC to a certain point of readiness.  From a business perspective, they can do that if they can see that the vehicle will have customers.  Europe may be quite happy to have a manned vehicle of their own, launched on a European launcher, with their own crews.  It would give them freedom to operate apart from NASA and also give them a manned space flight program and the ability to operate in LEO independently of the ISS.  This is something they've eyed before with Hermes, etc.  DC gives them the ability to get there at a very low cost, (against the expense of developing their own vehicle from scratch).  And DC's unique abilities as a lifting body which can potentially support EVA's without depressurizing the vehicle, longer flights, (correct me if I'm wrong on that...but from what I've gathered a manned DC can fly longer) etc. gives them something that cramped CST-100, for all it's Boeing and NASA endorsed virtues, isn't really designed for.  So maybe something is happening.  And then again, maybe not.  Certainly I agree there is lots of room for skepticism.

My own history with DC goes back to the 90's when it was the HL-20.  My Dad was NASA's program director on HL-20.  I got to go into the mock-up, etc.  I think there is a lot of validity to that kind of approach in terms of getting closer to aircraft like turnarounds, etc.  The HL-20 team were keenly aware of the danger and the shortcomings of the shuttle and saw a smaller vehicle as way to address a lot of the problems.  So I'm hoping she'll fly.  But who knows.  Everyone is entitled to their opinion.  I think the facts we have are sketchy at best, but maybe someone here knows more.

Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: GClark on 02/05/2015 07:32 am
On the subject of Dreamchaser & Europe...

IMNSHO it's worth remembering that Europe was rather deep into the XCRV before the Scrub pulled the plug on it.  Germany in particular has a history with these kinds of vehicles.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: rayleighscatter on 02/05/2015 08:28 pm
Europe has a lot of development history on lifting bodies even if they haven't launched one, yet. And they've studied lifting bodies more than capsules it seems. There may be an idea of collaborating with SNC and combining European research with SNC's.

It's also worth keeping in mind that ISS' life is currently at 5-9 years. If Germany or any other European nation (or the ESA) wants to maintain its manned space program the planning has to be underway now.   

The idea of the study doesn't have to be an SNC product either, heck, Dreamchaser was planned to be built by Lockheed. I don't see any reason why a European manufacturer couldn't build it instead.

It's at least a possibility.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Todd Martin on 03/03/2015 06:06 pm
I've been thinking for a while what DreamChaser really offers that is being neglected by NASA's choice of DragonRider and CST-100.  It's scalability.

We've seen from the multiple, very expensive re-designs of Orion that Capsule shaped re-entry craft are very limited in how big they can get.  A space-plane can be much larger.  The Space Shuttle is a great example, and it is not the upper limit on how big you could go.  DC would allow for continued investment and experience in space plane technology, paving the way for a next generation space shuttle. 

Large cargo return capability has not been needed yet because launch costs have made return & refurbishment of satellites cost prohibitive and ISRU cost prohibitive.  That limitation won't last forever.

If manufacturing in space is ever to become reality, or space tourism, or space colonization, then scaling up will be needed.  DC can pave that path forward.

Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: ChrisWilson68 on 03/03/2015 06:16 pm
I've been thinking for a while what DreamChaser really offers that is being neglected by NASA's choice of DragonRider and CST-100.  It's scalability.

We've seen from the multiple, very expensive re-designs of Orion that Capsule shaped re-entry craft are very limited in how big they can get.  A space-plane can be much larger.  The Space Shuttle is a great example, and it is not the upper limit on how big you could go.  DC would allow for continued investment and experience in space plane technology, paving the way for a next generation space shuttle. 

Large cargo return capability has not been needed yet because launch costs have made return & refurbishment of satellites cost prohibitive and ISRU cost prohibitive.  That limitation won't last forever.

If manufacturing in space is ever to become reality, or space tourism, or space colonization, then scaling up will be needed.  DC can pave that path forward.

To me, that's not a good argument for an operational lifting body vehicle now.  We should do now what's optimal for our current needs.  That will actually help bring us to the point where we need a larger vehicle more quickly.  When we reach the point where a large entry vehicle is what we need, the point is the time to put the resources into lifting body development, not before.

It's going to be a while.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: baldusi on 03/03/2015 07:47 pm
I see DreamChaser as what STS should have been preceded by. First an HL20 on crew rated Titan III to learn the necessary lessons on reusable segmented solids and returnable spacecraft. Then doing a full fledged STS like design.
Personally I believe something like an HL42 on some EELV-class Heavy would be an excellent LEO cargo craft. Probably able to put 10tonnes per flight on the ISS, or send some 16 pax to LEO. In the USD/kg it would probably be quite competitive.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: ChrisWilson68 on 03/03/2015 08:26 pm
I see DreamChaser as what STS should have been preceded by. First an HL20 on crew rated Titan III to learn the necessary lessons on reusable segmented solids and returnable spacecraft. Then doing a full fledged STS like design.
Personally I believe something like an HL42 on some EELV-class Heavy would be an excellent LEO cargo craft. Probably able to put 10tonnes per flight on the ISS, or send some 16 pax to LEO. In the USD/kg it would probably be quite competitive.

What if the lesson learned from the preceding vehicles you suggest is that one shouldn't build a vehicle like STS at all?
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Space Ghost 1962 on 03/03/2015 09:46 pm
I see DreamChaser as what STS should have been preceded by. First an HL20 on crew rated Titan III to learn the necessary lessons on reusable segmented solids and returnable spacecraft. Then doing a full fledged STS like design.
Personally I believe something like an HL42 on some EELV-class Heavy would be an excellent LEO cargo craft. Probably able to put 10tonnes per flight on the ISS, or send some 16 pax to LEO. In the USD/kg it would probably be quite competitive.

What if the lesson learned from the preceding vehicles you suggest is that one shouldn't build a vehicle like STS at all?
Both of you are getting at the nature of retrospection - that things would proceed differently.

Where it becomes "unstable" is in the way that it consequently departs, as Chris is implying here.

And then there are the less optimistic paths due to governmental consequentialism:

 1. It would have been better baldusi if you'd said ELV instead of Titan III/RSRB's etc - there was a likelihood of LOM / LOC with that program that was very significant, from MOL beginnings and on. Had it occurred it might have stopped such a program cold.

Some think that because of of Titan III issues, and Titan IV program costing, EELV as a consequence resulted in the quality LV results we've seen. I think about this while I watch OA and SX stumble a bit.

2. Shuttle was a very peculiar program in many ways. It had to be big given the shadow of the Saturn V it sort of replaced as a "soft power" symbol of America. No way a Titan / HL20 would serve this alone, yet hard to imagine a follow-on cargo or reusable booster program in parallel, given the "one vehicle" approach that Congress would allow.

3. Like Dynasoar that preceded it, or the antecedent's of Hermes / X-38, small space planes have a tough time making it through the budget battles for a variety of reasons. This in part was why lumping military launches (and all that that brings along like payload bay and cross range requirements) made it harder to defund Shuttle, even though things like the Taos compromise utterly undercut the ability to deliver on that, just in same the way that having the AF share Saturn with NASA/govt launches would have eventually soured.

4. Apollo, like OSP, also had considered a space plane design. Both went the same way. I think that's the issue that HL20 and Dreamchaser fought and lost on.

HL20 was only really possible as a STS-1 failure alternative. Which came close.

And with Orion, CST-100, and Dragon 2 - I can't see any similar scenario.

Best I can see is a replacement for Space Ship Two as an alternative for wealth space tourist joyrides.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Patchouli on 03/04/2015 01:56 am
I see DreamChaser as what STS should have been preceded by. First an HL20 on crew rated Titan III to learn the necessary lessons on reusable segmented solids and returnable spacecraft. Then doing a full fledged STS like design.
Personally I believe something like an HL42 on some EELV-class Heavy would be an excellent LEO cargo craft. Probably able to put 10tonnes per flight on the ISS, or send some 16 pax to LEO. In the USD/kg it would probably be quite competitive.

It was politics that had the first space plane become a space truck.

As for arguments of safety on the Titian III a vehicle on top of the rocket with an LAS would have escape the failures that occurred.

Now on to the advantages of Dream Chaser it's the only vehicle were all the orbital parts come back which could give it a big cost advantage not counting the LV.
Plus it's TPS despite the vehicles complexity might require the least amount of repairs between flights.

The CST-100 it

It has a low g reentry only 1.5 g, the landing mode is gentle, proven track record and has the best safety record.
A lot of people like to point out the bad parts of the shuttle, but no one ever gotten a back injury or broken teeth from a shuttle landing.
The lower g reentry also means less customers would need to be turned away due to health reasons.

Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: ChrisWilson68 on 03/04/2015 05:24 am
Now on to the advantages of Dream Chaser it's the only vehicle were all the orbital parts come back which could give it a big cost advantage not counting the LV.

I don't see the point of saying if you don't count the LV it might have a cost advantage.  If you're talking about the actual Dream Chaser in real life versus the actual Dragon 2, you can't ignore the cost of the launch vehicle.

If you're talking about more general speculation of what might have been or what might be -- well, a future version of Dragon might integrate the functionality that is currently in the trunk into the vehicle itself.  There's nothing about spaceplane versus capsule that makes that impossible.

Plus it's TPS despite the vehicles complexity might require the least amount of repairs between flights.

It might.  Or it might not.  There's no way to know.

The shuttle's TPS was supposed to be lower cost because it was reusable, but its fragility actually turned out to make it very high cost

It has a low g reentry only 1.5 g, the landing mode is gentle,

Far more gentle than is actually required.

proven track record and has the best safety record.

Huh?  Dream Chaser has no proven track record at all.  Spaceplanes have a pretty bad record of killing people.  Sure, shuttle didn't kill people as it was landing, but the way it was designed to land meant it had to be side mounted, and that did kill people.  You can't ignore the effects of the landing system during other phases of flight.

A lot of people like to point out the bad parts of the shuttle, but no one ever gotten a back injury or broken teeth from a shuttle landing.

No, they didn't get back injuries, they died.

Nobody got a back injury on Dragon 2, nor is anyone likely to.  That happened on another capsule when it had a ballistic re-entry because of a malfunction.  At Dragon's planned re-entry profile, nobody is getting a back injury.

At least capsules have the option of doing a ballistic re-entry if everything goes wrong.  A spaceplane would burn up instead.

The lower g reentry also means less customers would need to be turned away due to health reasons.

How many customers are actually going to be turned away from Dragon for health reasons?  Dragon does a lifting re-entry too, it's just not as much lift.  People lying down in couches during re-entry will have very little danger or discomfort from Dragon's re-entry.  Anyone would couldn't stand that isn't likely to be fit for a microgravity environment anyway.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: vt_hokie on 03/04/2015 07:25 am
I just wonder now whether all the taxpayer dollars that went into Dream Chaser simply vanished into a black hole, with Sierra Nevada owning the intellectual property related to a vehicle that will never fly, or whether there are still chapters to be written in the HL-20 saga.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: MattMason on 03/04/2015 01:04 pm
I just wonder now whether all the taxpayer dollars that went into Dream Chaser simply vanished into a black hole, with Sierra Nevada owning the intellectual property related to a vehicle that will never fly, or whether there are still chapters to be written in the HL-20 saga.

I'm a newbie here, but this sounds like unsubstantiated speculation.

For one, SNC is still pursuing avenues and projects that may bring the DC to flight, independent of NASA's choices. Countries or companies that don't like the terms to fly using a Dragon or CST-100 or who have their own space programs and "need a ride" without having to develop a craft from scratch may want one of these spacecraft. The DC can generally fly atop just about any launch vehicle with the proper thrust and safety standards.

Two,  SNC is more than the DC. They have been, for decades, a systems integrator for many satellite missions, commercial and military projects. Until shortly before the tragic incident in late October, the rocket motor used for the SpaceShipTwo rocket plane used an SNC-designed power plant.

Reports are that SNC had to let go a lot of people when they didn't get the Commercial Crew contract. But their loss doesn't imply, nor is there proof made public that I'm aware of, that anything questionable occurred in the use of what monies they did receive from NASA in their project development.

Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: SWGlassPit on 03/04/2015 03:38 pm
To an extent, that's the risk the government takes when it funds competitive development projects.  For the companies involved, the generation and ownership of intellectual property is a mitigation to the risk that they lose the follow-on contract.  If, as a rule, competition losers had to hand over all of the IP they generated to create the final proposal, you would see very few takers for advanced development projects.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Citabria on 03/04/2015 04:06 pm
American industry is no "black hole." SNC created jobs with the money. And they have subcontractors, some of whom have subcontractors (such as my employer). So much of the money went to many American workers, including me.

http://www.onlineamd.com/sakor-technologies-test-dream-chaser-022615.aspx#.VPc92nzF-gQ (http://www.onlineamd.com/sakor-technologies-test-dream-chaser-022615.aspx#.VPc92nzF-gQ)
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Lars-J on 03/04/2015 04:13 pm
So is the 2nd drop test still happening?
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Eerie on 03/04/2015 04:33 pm
We've seen from the multiple, very expensive re-designs of Orion that Capsule shaped re-entry craft are very limited in how big they can get.

Huh? How do you get to this conclusion?
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: eric z on 03/04/2015 04:48 pm
 This is no doubt a dumb question, but why could not Dreamchaser be reproposed as an experimental program, to keep intact our accumulated expertise in this area, among other reasons. Or does the AF efforts in this regard make what I am saying redudant? Thanks!
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Lars-J on 03/04/2015 04:55 pm
This is no doubt a dumb question, but why could not Dreamchaser be reproposed as an experimental program, to keep intact our accumulated expertise in this area, among other reasons. Or does the AF efforts in this regard make what I am saying redudant? Thanks!

The AF already has the X-37 for that purpose.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: ChrisWilson68 on 03/04/2015 05:59 pm
This is no doubt a dumb question, but why could not Dreamchaser be reproposed as an experimental program, to keep intact our accumulated expertise in this area, among other reasons. Or does the AF efforts in this regard make what I am saying redudant? Thanks!

If you focus too much on keeping intact all capabilities that have been developed, you miss out on opportunities to develop other capabilities.  There simply isn't a need to do further work on DreamChaser unless and until we decide to fund it to develop an operational vehicle.  And we've decided to fund two other operational vehicles instead, for a market of about two missions a year.  Someday, if we need more capability, we can consider Dream Chaser or something like it again.  In the meantime, Dragon and CST-100 are more than enough.

Lets instead make use of what we have and do a lot more flights to and from orbit.  Lets build fuel depots and in-space-only exploration vehicles and habitats.  Lets do landers for other worlds.  We don't need to stay obsessed with getting to and from orbit.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: JAFO on 03/04/2015 06:53 pm
I see DreamChaser as what STS should have been preceded by. First an HL20 on crew rated Titan III to learn the necessary lessons on reusable segmented solids and returnable spacecraft. Then doing a full fledged STS like design.
Personally I believe something like an HL42 on some EELV-class Heavy would be an excellent LEO cargo craft. Probably able to put 10tonnes per flight on the ISS, or send some 16 pax to LEO. In the USD/kg it would probably be quite competitive.

It was politics that had the first space plane become a space truck.


In the early 1970s, in the days before Nixon was reelected for a second term, HR Halderman approach Apollo 8 astronaut Bill Anders (who was the executive secretary of the National Aeronautics and Space Council) and asked which of the competing shuttle designs would bring more jobs to California: the large shuttle or the smaller one? Anders replied the larger one, and the die was cast.

From Select Astronaut Observations and Highlights of Space Shuttle Program Payloads and Experiments
Supplement to Wings in Orbit: Scientific and Engineering Legacies of the Space Shuttle (NASA/SP-2010-3409) NASA/TM–2011-216150
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: vt_hokie on 03/04/2015 08:21 pm
American industry is no "black hole." SNC created jobs with the money. And they have subcontractors, some of whom have subcontractors (such as my employer). So much of the money went to many American workers, including me.

http://www.onlineamd.com/sakor-technologies-test-dream-chaser-022615.aspx#.VPc92nzF-gQ (http://www.onlineamd.com/sakor-technologies-test-dream-chaser-022615.aspx#.VPc92nzF-gQ)

Point taken. My first job out of college was to work on the X-33 program, so I guess I'm just a little tired of seeing the list of vehicles that never got a chance to fly continue to grow ever longer!
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: ChrisWilson68 on 03/04/2015 09:20 pm
American industry is no "black hole." SNC created jobs with the money. And they have subcontractors, some of whom have subcontractors (such as my employer). So much of the money went to many American workers, including me.

http://www.onlineamd.com/sakor-technologies-test-dream-chaser-022615.aspx#.VPc92nzF-gQ (http://www.onlineamd.com/sakor-technologies-test-dream-chaser-022615.aspx#.VPc92nzF-gQ)

Point taken. My first job out of college was to work on the X-33 program, so I guess I'm just a little tired of seeing the list of vehicles that never got a chance to fly continue to grow ever longer!

9 out of 10 Silicon Valley start-ups fail too.  I don't consider those efforts wasted.  They're a necessary part of exploring the options -- just as the work done on X-33, Dream Chaser, Kistler, NASP, etc. were.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Mike Harris-Stone on 03/05/2015 03:44 am
So is the 2nd drop test still happening?

Yes.  According to both NASA and SNC.

Also, a couple of European blogs and news sources have indicated the 2016 unmanned orbital test flight scheduled on an Atlas V is still on.  I don't know how accurate that is. 
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Mike Harris-Stone on 03/05/2015 04:01 am

Huh?  Dream Chaser has no proven track record at all.  Spaceplanes have a pretty bad record of killing people.  Sure, shuttle didn't kill people as it was landing, but the way it was designed to land meant it had to be side mounted, and that did kill people.  You can't ignore the effects of the landing system during other phases of flight.


Excuse me, but can you provide some logic for your following assertion:  "the way it was designed to land meant it had to be side mounted.."   That makes no sense at all.  The X-37 utilizes a runway landing and it isn't side mounted.  How does a runway landing require side mounting.  Explain...

One could just as easily argue that the SRB's are what killed the crew since a) an SRB failure doomed Challenger and b) SRB vibration caused the foam to come off the fuel tank on Columbia.  (someone please correct me if I'm wrong on b))






Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: ChrisWilson68 on 03/05/2015 04:45 am

Huh?  Dream Chaser has no proven track record at all.  Spaceplanes have a pretty bad record of killing people.  Sure, shuttle didn't kill people as it was landing, but the way it was designed to land meant it had to be side mounted, and that did kill people.  You can't ignore the effects of the landing system during other phases of flight.


Excuse me, but can you provide some logic for your following assertion:  "the way it was designed to land meant it had to be side mounted.."   That makes no sense at all.  The X-37 utilizes a runway landing and it isn't side mounted.  How does a runway landing require side mounting.  Explain...

X-37 launches inside a payload fairing.  It can do that because it's small and the launch vehicle can lift both it and the fairing.  It becomes harder as the size of the vehicle goes up.  A vehicle without wings is easier to put on the top of a stack.

Anyway, Columbia was lost because the reinforced carbon-carbon on the leading edge of the wing was hit.  This leading-edge section was particularly fragile.  No wing, no leading edge, no destruction of Columbia.

One could just as easily argue that the SRB's are what killed the crew since a) an SRB failure doomed Challenger and b) SRB vibration caused the foam to come off the fuel tank on Columbia.  (someone please correct me if I'm wrong on b))

Sure.  I didn't say wings were the only cause.  There's always a whole chain of causes, and the whole chain needs to be there for the failure to happen.  Having wings was one link in that chain.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: A_M_Swallow on 03/05/2015 06:46 am

Huh?  Dream Chaser has no proven track record at all.  Spaceplanes have a pretty bad record of killing people.  Sure, shuttle didn't kill people as it was landing, but the way it was designed to land meant it had to be side mounted, and that did kill people.  You can't ignore the effects of the landing system during other phases of flight.


Excuse me, but can you provide some logic for your following assertion:  "the way it was designed to land meant it had to be side mounted.."   That makes no sense at all.  The X-37 utilizes a runway landing and it isn't side mounted.  How does a runway landing require side mounting.  Explain...
{snip}

The Shuttle's main engines were in the tail of the orbiter. There was no where else to put a very large drop tank than on the side. Putting the fuel tank behind the engines would result in the thrusters destroying the tank.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: dror on 03/05/2015 12:11 pm
I know it was discussed befor,
I think dream chaser (or any spaceplane ) could have had an advantage only if it was planed to be it's LV's seconed stage.
Now, in light of recent successful testing of F9 first stage ladings, and in light of neglecting the efforts to reuse F9 seconed stage, it seems like a reusable mini shuttle on top of a F9R booster could have been the most cost effective solution for commercial resupply and commercial crew transportation.
The vehicle could be a dream chaser with larger fuel tanks, or maybe external tanks, or it could become totally diffrent.
It would be designed according to F9R first stage capabilities. If the final design is not capable enogh, then a bigger version could be designed for FH.

Do we know what was the planned dV for a fully loaded dream chaser?
Could it make it to orbit on a FHR core and booster with no stage 2 ?
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Rocket Science on 03/05/2015 12:27 pm
I know it was discussed befor,
I think dream chaser (or any spaceplane ) could have had an advantage only if it was planed to be it's LV's seconed stage.
Now, in light of recent successful testing of F9 first stage ladings, and in light of neglecting the efforts to reuse F9 seconed stage, it seems like a reusable mini shuttle on top of a F9R booster could have been the most cost effective solution for commercial resupply and commercial crew transportation.
The vehicle could be a dream chaser with larger fuel tanks, or maybe external tanks, or it could become totally diffrent.
It would be designed according to F9R first stage capabilities. If the final design is not capable enogh, then a bigger version could be designed for FH.

Do we know what was the planned dV for a fully loaded dream chaser?
Could it make it to orbit on a FHR core and booster with no stage 2 ?
Interesting idea but remember SpaceX has yet to demonstrate a successful F9R landing much less re-use. If they actually succeed then new concepts are possible...
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: kevinof on 03/05/2015 01:59 pm
I think, as Rocket Science points out that once/if Space X prove re-usability of the first stage then this could be a very interesting idea. Stick a Merlin VAC  on a new/modified Dream chaser, bigger tanks (or maybe as you say external/disposable tanks) and you've got a re-usable winged solution.

Would love to see that happen. Always been a fan of Dream chaser but only when it makes sense. The current config of sticking it on top of a disposable 1st and 2nd stage never worked for me.

I know it was discussed befor,
I think dream chaser (or any spaceplane ) could have had an advantage only if it was planed to be it's LV's seconed stage.
Now, in light of recent successful testing of F9 first stage ladings, and in light of neglecting the efforts to reuse F9 seconed stage, it seems like a reusable mini shuttle on top of a F9R booster could have been the most cost effective solution for commercial resupply and commercial crew transportation.
The vehicle could be a dream chaser with larger fuel tanks, or maybe external tanks, or it could become totally diffrent.
It would be designed according to F9R first stage capabilities. If the final design is not capable enogh, then a bigger version could be designed for FH.

Do we know what was the planned dV for a fully loaded dream chaser?
Could it make it to orbit on a FHR core and booster with no stage 2 ?
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: TrevorMonty on 03/05/2015 02:11 pm
American industry is no "black hole." SNC created jobs with the money. And they have subcontractors, some of whom have subcontractors (such as my employer). So much of the money went to many American workers, including me.

http://www.onlineamd.com/sakor-technologies-test-dream-chaser-022615.aspx#.VPc92nzF-gQ (http://www.onlineamd.com/sakor-technologies-test-dream-chaser-022615.aspx#.VPc92nzF-gQ)

Point taken. My first job out of college was to work on the X-33 program, so I guess I'm just a little tired of seeing the list of vehicles that never got a chance to fly continue to grow ever longer!
Its not all bad, XCOR was born from a failed startup ie Rotary Rockets. Financially they maybe a failure but their technology knowledge lives on in their ex employees who tend to apply elsewhere.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Rocket Science on 03/05/2015 03:52 pm
Why is this thread becoming so maudlin... SNC is still in business and feelers are still out...
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: cro-magnon gramps on 03/05/2015 04:18 pm

If you focus too much on keeping intact all capabilities that have been developed, you miss out on opportunities to develop other capabilities.  There simply isn't a need to do further work on DreamChaser unless and until we decide to fund it to develop an operational vehicle.  And we've decided to fund two other operational vehicles instead, for a market of about two missions a year.  Someday, if we need more capability, we can consider Dream Chaser or something like it again.  In the meantime, Dragon and CST-100 are more than enough.

Lets instead make use of what we have and do a lot more flights to and from orbit.  Lets build fuel depots and in-space-only exploration vehicles and habitats.  Lets do landers for other worlds.  We don't need to stay obsessed with getting to and from orbit.

Simple question: Who are the "WE" that you are talking about. We "The General World Space Community"!! We "NASA and Congressional Oversight"!! or We "Commercial Space, NEW or OLDE"!!
     
Gramps
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: cro-magnon gramps on 03/05/2015 04:44 pm
Why is this thread becoming so maudlin... SNC is still in business and feelers are still out...

Indeed, I came today through the front page of NSF, and reading this page of posts, I had the feeling that there had been bad news, and we were having a Wake for the DC... had to go back two pages to figure out that DC was still an active project of SNC... nothing like having an obituary in the paper before one has breathed their last breath...
   
  While I can agree that in the present circumstances DC is on it's back foot, and trying to keep steady, it still has potential, as has been pointed out. As well, as it has been pointed out, as a base for further research in lifting bodies, it has merit, regardless of the USAF project. The latter being secretive, where as an Advanced DC would be in some respects more out in the open, and being commercial would have different forces acting on it: negative and positive.
Funding does NOT have to always come through US Gov't Pork, Agency or Committee. If DC is worth the effort, it could appeal to someone with the interest and who has a few dollars to advance the technology. That we don't need it now in terms of US Gov't need, it is possible, if not probably, in the near future, 5-15 years, an advanced DC might be of use in the general Space Ecology. (Think of the way birds inhabit different habitats) In the meantime, the use of DC by other countries would and should, keep the technology growing.

Gramps
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: ChrisWilson68 on 03/05/2015 06:02 pm
That we don't need it now in terms of US Gov't need, it is possible, if not probably, in the near future, 5-15 years, an advanced DC might be of use in the general Space Ecology. (Think of the way birds inhabit different habitats)

Bird species also go extinct when there isn't a niche for them, or when their niche is filled by other species.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: ChrisWilson68 on 03/05/2015 06:02 pm
I know it was discussed befor,
I think dream chaser (or any spaceplane ) could have had an advantage only if it was planed to be it's LV's seconed stage.
Now, in light of recent successful testing of F9 first stage ladings, and in light of neglecting the efforts to reuse F9 seconed stage, it seems like a reusable mini shuttle on top of a F9R booster could have been the most cost effective solution for commercial resupply and commercial crew transportation.
The vehicle could be a dream chaser with larger fuel tanks, or maybe external tanks, or it could become totally diffrent.
It would be designed according to F9R first stage capabilities. If the final design is not capable enogh, then a bigger version could be designed for FH.

Do we know what was the planned dV for a fully loaded dream chaser?
Could it make it to orbit on a FHR core and booster with no stage 2 ?
Interesting idea but remember SpaceX has yet to demonstrate a successful F9R landing much less re-use. If they actually succeed then new concepts are possible...

There's nothing wrong with thinking ahead.  SpaceX has a plan to re-use their first stages, and they've already retired most of the risk in that plan.  No need to ding someone for considering what to do if SpaceX succeeds.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: cro-magnon gramps on 03/05/2015 06:23 pm
That we don't need it now in terms of US Gov't need, it is possible, if not probably, in the near future, 5-15 years, an advanced DC might be of use in the general Space Ecology. (Think of the way birds inhabit different habitats)

Bird species also go extinct when there isn't a niche for them, or when their niche is filled by other species.

True that some species will go extinct, but without some evolving into something else where niches exist, there might not be any birds around today... Lets see if DC has the genes necessary to find another niche, and evolve...  ;D

The Crazy Optimist
Gramps
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Rocket Science on 03/05/2015 06:44 pm
I know it was discussed befor,
I think dream chaser (or any spaceplane ) could have had an advantage only if it was planed to be it's LV's seconed stage.
Now, in light of recent successful testing of F9 first stage ladings, and in light of neglecting the efforts to reuse F9 seconed stage, it seems like a reusable mini shuttle on top of a F9R booster could have been the most cost effective solution for commercial resupply and commercial crew transportation.
The vehicle could be a dream chaser with larger fuel tanks, or maybe external tanks, or it could become totally diffrent.
It would be designed according to F9R first stage capabilities. If the final design is not capable enogh, then a bigger version could be designed for FH.

Do we know what was the planned dV for a fully loaded dream chaser?
Could it make it to orbit on a FHR core and booster with no stage 2 ?
Interesting idea but remember SpaceX has yet to demonstrate a successful F9R landing much less re-use. If they actually succeed then new concepts are possible...

There's nothing wrong with thinking ahead.  SpaceX has a plan to re-use their first stages, and they've already retired most of the risk in that plan.  No need to ding someone for considering what to do if SpaceX succeeds.
No ding CW, just stating fact as it is still in a proof of concept form... I continue to support SpaceX and cheer them on for trying; I’m just not a “cult member”...
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Patchouli on 03/17/2015 06:26 pm

Point taken. My first job out of college was to work on the X-33 program, so I guess I'm just a little tired of seeing the list of vehicles that never got a chance to fly continue to grow ever longer!

I consider the X-33 more of a political kill then an engineering failure.

I know it was discussed befor,
I think dream chaser (or any spaceplane ) could have had an advantage only if it was planed to be it's LV's seconed stage.
Now, in light of recent successful testing of F9 first stage ladings, and in light of neglecting the efforts to reuse F9 seconed stage, it seems like a reusable mini shuttle on top of a F9R booster could have been the most cost effective solution for commercial resupply and commercial crew transportation.
The vehicle could be a dream chaser with larger fuel tanks, or maybe external tanks, or it could become totally diffrent.
It would be designed according to F9R first stage capabilities. If the final design is not capable enogh, then a bigger version could be designed for FH.

Do we know what was the planned dV for a fully loaded dream chaser?
Could it make it to orbit on a FHR core and booster with no stage 2 ?

In some ways I think DC could have a lower cost refurbishment between mission then Dragon V2 since it all comes back and the landing mode is less likely to damage the TPS then VTOL rocket descent.
Plus the use of non toxic RCS propellants would likely have a significant cost saving in ground processing of the vehicle even though the up front R&D costs were higher.
I'm surprised someone like Jeff Bezo hasn't decided to fund it out of their pockets as it's the only vehicle I seen that appears to be able to compete with Dragon V2 on equal terms.

As for acting as it's own upper stage a DC with hydrogen or methane engines and a MAKS style drop tank could be a cost effective solution to do away with a disposable second stage.
There will be some cosine losses as on the shuttle but since the mass constraints won't be as bad a tougher TPS and or a tank insulation less likely to shed can be used.

Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: adrianwyard on 03/17/2015 08:25 pm
Dream Chaser Cargo System is announced here:

http://forum.nasaspaceflight.com/index.php?topic=29416.msg1347170#msg1347170

There's an image which seems to show unpressurized cargo behind the spacecraft (they'll launch this DC in a fairing). But as has been asked (so many times before) won't the orbital maneuvering engines plume the cargo?
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Beittil on 03/17/2015 09:34 pm
Is it me or does this seem almost like a space pickup truck with a space trailer behind it :S What a needlessly complex solution. Stacking a cargo module on a rocket, with a DC on top of that... why!
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: rayleighscatter on 03/17/2015 09:55 pm
Is it me or does this seem almost like a space pickup truck with a space trailer behind it :S What a needlessly complex solution. Stacking a cargo module on a rocket, with a DC on top of that... why!
Upmass requirements are much higher than return mass requirements. A vehicle fully capable of that same return mass as upmass would be considerably larger, weigh considerably more, and require a larger launch vehicle.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: AnalogMan on 03/17/2015 10:58 pm
Just to note that there is a thread dedicated to the cargo version of Dream Chaser:

CRS-2: Dream Chaser Cargo System
http://forum.nasaspaceflight.com/index.php?topic=37049.0 (http://forum.nasaspaceflight.com/index.php?topic=37049.0)
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: JasonAW3 on 03/20/2015 06:48 pm
Is it me or does this seem almost like a space pickup truck with a space trailer behind it :S What a needlessly complex solution. Stacking a cargo module on a rocket, with a DC on top of that... why!

Not really that much different from Lockheed's original Crew Spacecraft design.

The second part is supposed to be for externally stored cargo so it can be offloaded via the Canadarm.  It also has the advantage that it can also be used for either a disposable segment for non-ER trash or as a short term satelitte that could be used for "getaway specials".

I suspect that the Cargo varient is intended to be ableto be used as a crew return vehicle in an emergency, or if a window opens in the schedule that SNC might take advantage of.  This would also explain why they haven't canceled their pad and flight abort tests.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Chris Bergin on 03/23/2015 08:45 pm
Crewed Dream Chaser still alive and kicking with a SAA deal with NASA to extend CCiCAP work until 2016! Maybe the second free flight is still on.

Will write an article.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: cro-magnon gramps on 03/23/2015 09:55 pm
Crewed Dream Chaser still alive and kicking with a SAA deal with NASA to extend CCiCAP work until 2016! Maybe the second free flight is still on.

Will write an article.

Fist Pumpin' YES!!! Great News...  :D :D

Gramps
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: BrightLight on 03/23/2015 11:55 pm
Crewed Dream Chaser still alive and kicking with a SAA deal with NASA to extend CCiCAP work until 2016! Maybe the second free flight is still on.

Will write an article.

Fist Pumpin' YES!!! Great News...  :D :D

Gramps
"Holy forth of July wienie roast, what do we have here"
where did the funds come from for SNC to continue this work? - fantastic news.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Chris Bergin on 03/24/2015 12:04 am
It's not as amazing as we hoped, it's unfunded - an additional milestone under SAA, but it'll have benefits. Article shortly.

Article on the update thread, here:
http://forum.nasaspaceflight.com/index.php?topic=29416.msg1349766#msg1349766
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Rocket Science on 03/24/2015 01:07 am
Time to say it again "I've been dead before"...
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: rayleighscatter on 03/24/2015 07:32 pm
I was a little confused, would this put SNC through the CDR process, or just closer to it?
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Chris Bergin on 03/24/2015 08:45 pm
I was a little confused, would this put SNC through the CDR process, or just closer to it?

She was put through the PDR, not CDR :)

http://www.nasaspaceflight.com/2012/06/dream-chaser-passes-pdr-integrated-system-testing/
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: cro-magnon gramps on 03/24/2015 09:07 pm
I was a little confused, would this put SNC through the CDR process, or just closer to it?

She was put through the PDR, not CDR :)

http://www.nasaspaceflight.com/2012/06/dream-chaser-passes-pdr-integrated-system-testing/


Quote from Chris' recent article: An agreement has been was reached for SNC to continue to work with NASA through to the Critical Design Review (CDR) level of maturity for the vehicle.

I would take this to mean that DC at the end of the work would have gone through CDR...

Correction welcome  ;)

Gramps

edit grammar
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: rayleighscatter on 03/24/2015 10:00 pm
I was a little confused, would this put SNC through the CDR process, or just closer to it?

She was put through the PDR, not CDR :)

http://www.nasaspaceflight.com/2012/06/dream-chaser-passes-pdr-integrated-system-testing/


Quote from Chris' recent article: An agreement has been was reached for SNC to continue to work with NASA through to the Critical Design Review (CDR) level of maturity for the vehicle.

I would take this to mean that DC at the end of the work would have gone through CDR...

Correction welcome  ;)

Gramps

edit grammar
Thanks, I think it was this that threw me a little bit since I read it as approaching but not reaching CDR.
Quote
This additional milestone will allow SNC to demonstrate the advancement of the Dream Chaser Space System design from a Preliminary Design Review (PDR) level of maturity toward a Critical Design Review (CDR) level.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: cro-magnon gramps on 03/24/2015 10:18 pm
I was a little confused, would this put SNC through the CDR process, or just closer to it?

She was put through the PDR, not CDR :)

http://www.nasaspaceflight.com/2012/06/dream-chaser-passes-pdr-integrated-system-testing/


Quote from Chris' recent article: An agreement has been was reached for SNC to continue to work with NASA through to the Critical Design Review (CDR) level of maturity for the vehicle.

I would take this to mean that DC at the end of the work would have gone through CDR...

Correction welcome  ;)

Gramps

edit grammar
Thanks, I think it was this that threw me a little bit since I read it as approaching but not reaching CDR.
Quote
This additional milestone will allow SNC to demonstrate the advancement of the Dream Chaser Space System design from a Preliminary Design Review (PDR) level of maturity toward a Critical Design Review (CDR) level.

Yes I can see where that would make it seem ambiguous. But if you think of the additional milestone, as a stepping stone, and the completed agreement itself as leading to a full CDR Level of Maturity, as the end product, the two quotes begin to make sense.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: daveklingler on 03/25/2015 05:29 am
I guess I haven't been paying enough attention.  I'm a bit puzzled by the new folding wings.  Can someone please explain how that's come about?

It seems to me that folding wings cause a structural weight gain in DC, as well as the mass of the 5-meter fairing.  Is this just for the cargo version?  What gives?
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: cro-magnon gramps on 03/25/2015 07:39 am
I guess I haven't been paying enough attention.  I'm a bit puzzled by the new folding wings.  Can someone please explain how that's come about?

It seems to me that folding wings cause a structural weight gain in DC, as well as the mass of the 5-meter fairing.  Is this just for the cargo version?  What gives?

Found this thread that may answer your questions:
http://forum.nasaspaceflight.com/index.php?topic=37049.msg1347055#msg1347055
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: vapour_nudge on 03/25/2015 08:22 am
I was a little confused, would this put SNC through the CDR process, or just closer to it?

She was put through the PDR, not CDR :)

http://www.nasaspaceflight.com/2012/06/dream-chaser-passes-pdr-integrated-system-testing/
So, it would appear the proposed November test flight next year on an Atlas (as was once planned) is definitely off? Can anyone confirm this either way?
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Rocket Science on 03/25/2015 09:35 am
Is it me or does this seem almost like a space pickup truck with a space trailer behind it :S What a needlessly complex solution. Stacking a cargo module on a rocket, with a DC on top of that... why!

Not really that much different from Lockheed's original Crew Spacecraft design.

The second part is supposed to be for externally stored cargo so it can be offloaded via the Canadarm.  It also has the advantage that it can also be used for either a disposable segment for non-ER trash or as a short term satelitte that could be used for "getaway specials".

I suspect that the Cargo varient is intended to be ableto be used as a crew return vehicle in an emergency, or if a window opens in the schedule that SNC might take advantage of.  This would also explain why they haven't canceled their pad and flight abort tests.
To refresh folks' memory...
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: vapour_nudge on 03/28/2015 12:29 am
I was a little confused, would this put SNC through the CDR process, or just closer to it?

She was put through the PDR, not CDR :)

http://www.nasaspaceflight.com/2012/06/dream-chaser-passes-pdr-integrated-system-testing/
So, it would appear the proposed November test flight next year on an Atlas (as was once planned) is definitely off? Can anyone confirm this either way?
bump
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Mike Harris-Stone on 04/02/2015 01:40 am
Interesting article on DC in Satellite Today magazine.

Mark Sirangelo says that are working on a profile that would have the first DC reach orbit in 2018.

http://www.satellitetoday.com/launch/2015/03/31/sierra-nevada-corporation-details-future-dream-chaser-mission-concepts/

It also touches on international developments for DC.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: TrevorMonty on 04/02/2015 04:43 pm
Nice to see project DC is still very much alive. I like the space tug concept, ie a manned Jupiter.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Star One on 04/02/2015 05:58 pm
Interesting read and I'm glad to hear that DC is still progressing in a variety of forms. Just hope their prediction for the LEO satellite repair market does materialise.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: yg1968 on 04/03/2015 12:13 pm
Interesting article on DC in Satellite Today magazine.

Mark Sirangelo says that are working on a profile that would have the first DC reach orbit in 2018.

http://www.satellitetoday.com/launch/2015/03/31/sierra-nevada-corporation-details-future-dream-chaser-mission-concepts/

It also touches on international developments for DC.

Interesting that unmanned DC seems to need the upgraded Falcon 9:

Quote
Unmanned missions can launch with Ariane 5, H2B, and potentially the Falcon Heavy or upgraded Falcon 9 rockets. Manned missions are currently designed to launch on the Atlas 5. SNC plans to use United Launch Alliance’s (ULA) next generation launch system in lieu of the Atlas 5 once the rocket is discontinued.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: arachnitect on 04/03/2015 03:44 pm
Interesting article on DC in Satellite Today magazine.

Mark Sirangelo says that are working on a profile that would have the first DC reach orbit in 2018.

http://www.satellitetoday.com/launch/2015/03/31/sierra-nevada-corporation-details-future-dream-chaser-mission-concepts/

It also touches on international developments for DC.

Interesting that unmanned DC seems to need the upgraded Falcon 9:

Quote
Unmanned missions can launch with Ariane 5, H2B, and potentially the Falcon Heavy or upgraded Falcon 9 rockets. Manned missions are currently designed to launch on the Atlas 5. SNC plans to use United Launch Alliance’s (ULA) next generation launch system in lieu of the Atlas 5 once the rocket is discontinued.

They want to take 5.5 tons per flight. They need a big rocket.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Archibald on 04/05/2015 07:01 am
Quote
This version of Dream Chaser would operate in Low Earth Orbit (LEO) up to about 1,000 nautical miles
interesting
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: baldusi on 04/05/2015 02:02 pm
Interesting article on DC in Satellite Today magazine.

Mark Sirangelo says that are working on a profile that would have the first DC reach orbit in 2018.

http://www.satellitetoday.com/launch/2015/03/31/sierra-nevada-corporation-details-future-dream-chaser-mission-concepts/

It also touches on international developments for DC.

Interesting that unmanned DC seems to need the upgraded Falcon 9:

Quote
Unmanned missions can launch with Ariane 5, H2B, and potentially the Falcon Heavy or upgraded Falcon 9 rockets. Manned missions are currently designed to launch on the Atlas 5. SNC plans to use United Launch Alliance’s (ULA) next generation launch system in lieu of the Atlas 5 once the rocket is discontinued.
Given that according to NLS site Falcon 9 v1.1 does about 15tonnes to a 51.7deg 350km circular orbit, and only Atlas V 551 surpasses it with 16, and H-2B does 16.5tonnes, they either want the reusable Falcon, or their minimum performance is 16+ tonnes and might even use an Atlas V 552. In any case they're are talking about three of the top four most expensive rockets.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: baldusi on 04/07/2015 03:02 pm
Dream Chaser® Cargo System Launches on Atlas V Concept of Operation Video

Published on Apr 6, 2015
Sierra Nevada Corporation’s (SNC) Dream Chaser® Cargo System is a mission variant of the Dream Chaser Space System that exceeds all NASA cargo transportation requirements to the International Space Station (ISS). The Dream Chaser Cargo System utilizes a reusable, lifting-body spacecraft and is capable of transporting pressurized and unpressurized cargo concurrently - returning cargo and sensitive science payloads to a low-g and gentle runway landing.

https://youtu.be/uHJ2QV0nPEA
Ha! That's an Atlas V 552! That is an expensive (and quite powerful) LV. I would guess somewhere around 18.5tonnes to ISS injection orbit (350km at 51.6deg). That would require an enhanced Falcon 9. But I'm surprised since the the H-2B can barely put 16.5tonnes to that orbit.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: JasonAW3 on 04/07/2015 04:35 pm
Dream Chaser® Cargo System Launches on Atlas V Concept of Operation Video

Published on Apr 6, 2015
Sierra Nevada Corporation’s (SNC) Dream Chaser® Cargo System is a mission variant of the Dream Chaser Space System that exceeds all NASA cargo transportation requirements to the International Space Station (ISS). The Dream Chaser Cargo System utilizes a reusable, lifting-body spacecraft and is capable of transporting pressurized and unpressurized cargo concurrently - returning cargo and sensitive science payloads to a low-g and gentle runway landing.

https://youtu.be/uHJ2QV0nPEA
Ha! That's an Atlas V 552! That is an expensive (and quite powerful) LV. I would guess somewhere around 18.5tonnes to ISS injection orbit (350km at 51.6deg). That would require an enhanced Falcon 9. But I'm surprised since the the H-2B can barely put 16.5tonnes to that orbit.

Looking at the front end profile of this design, it appears that SNC is still looking at a Manned version of this craft.  Simplified curves on the upper surface would provide better aerodynamics and slightly lower mass, but would make it harder to convert to a manned version.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Zed_Noir on 04/08/2015 07:52 am
Quote

Looking at the front end profile of this design, it appears that SNC is still looking at a Manned version of this craft.  Simplified curves on the upper surface would provide better aerodynamics and slightly lower mass, but would make it harder to convert to a manned version.

If you mod the craft's profile than you are making a new vehicle with different internal structure and different aerodynamics. SNC have barely enough cash for one vehicle development.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Archibald on 04/08/2015 08:48 am
Never realized that DC wings folded and that it fit into a 5m diameter fairing. So an Ariane 5 could launch it without aerodynamic issues...
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: kevinof on 04/08/2015 09:40 am
It doesn't. SNC are proposing a (smaller?) version that will have folding wings.

Never realized that DC wings folded and that it fit into a 5m diameter fairing. So an Ariane 5 could launch it without aerodynamic issues...
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: woods170 on 04/08/2015 11:54 am
Never realized that DC wings folded and that it fit into a 5m diameter fairing. So an Ariane 5 could launch it without aerodynamic issues...
Yes, an Ariane 5 could launch it, but IMO Ariane 5 will not launch it.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: ChrisWilson68 on 04/23/2015 03:00 am
I was a little confused, would this put SNC through the CDR process, or just closer to it?

She was put through the PDR, not CDR :)

http://www.nasaspaceflight.com/2012/06/dream-chaser-passes-pdr-integrated-system-testing/


Quote from Chris' recent article: An agreement has been was reached for SNC to continue to work with NASA through to the Critical Design Review (CDR) level of maturity for the vehicle.

I would take this to mean that DC at the end of the work would have gone through CDR...

Correction welcome  ;)

More of a clarification that a correction: this news doesn't mean that DC is likely to actually reach CDR.  There's no news that anybody has funded development through CDR.  The agreement that was signed just says that for any work SNC does through CDR, they can ask NASA for advice and NASA will advise them.

Nice to see project DC is still very much alive. I like the space tug concept, ie a manned Jupiter.

Maybe alive, but in a coma.  SNC is keeping it barely alive enough to try to look viable for CRS2 or anyone else they can try to get to fund it.

The bottom line is that there is currently no funding for any variant of DC and unless and until that changes, it's unlikely any version of DC will reach orbit.

Remember earlier this year when SNC was saying the drop test was going to happen after all, possibly as early as March?  Obviously, that didn't happen.

There's been a steady stream of talk coming out of SNC.  So far, no actions since they lost CCtCap.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Rocket Science on 04/23/2015 02:15 pm
Drop test before end of this year has been mentioned...
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: GreenShrike on 04/23/2015 05:32 pm
Drop test before end of this year has been mentioned...

In December, I think, which is -- possibly conveniently, possibly deliberately -- after the CRS2 award. Plenty of time to shelve DC without further major financial expenditures should they not win a NASA contract.

I'd feel a good deal less cynical if this wasn't the case. :-/
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: The Amazing Catstronaut on 04/23/2015 10:02 pm

In December, I think, which is -- possibly conveniently, possibly deliberately -- after the CRS2 award. Plenty of time to shelve DC without further major financial expenditures should they not win a NASA contract.

I'd feel a good deal less cynical if this wasn't the case. :-/

To be fair to them, there's no point in them bleeding money and labour and no small amount of corporate prestige on something that's not going to sell, if it isn't going to sell. Better to wait and see first.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: ChrisWilson68 on 04/24/2015 04:02 am

In December, I think, which is -- possibly conveniently, possibly deliberately -- after the CRS2 award. Plenty of time to shelve DC without further major financial expenditures should they not win a NASA contract.

I'd feel a good deal less cynical if this wasn't the case. :-/

To be fair to them, there's no point in them bleeding money and labour and no small amount of corporate prestige on something that's not going to sell, if it isn't going to sell. Better to wait and see first.

Absolutely, I don't blame them for making a rational decision based on the reality of the economics.

What I do mind is that they're not very honest about it.  You don't hear them publicly saying there will only be another drop test if they get a contract from someone to make it worthwhile.  They consistently paint a very rosy picture in everything they say publicly.  They never acknowledge any uncertainty.  They don't even use the future tense -- they always talk about Dream Chaser as if it's something that already exists.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Patchouli on 04/24/2015 06:23 am

In December, I think, which is -- possibly conveniently, possibly deliberately -- after the CRS2 award. Plenty of time to shelve DC without further major financial expenditures should they not win a NASA contract.

I'd feel a good deal less cynical if this wasn't the case. :-/

To be fair to them, there's no point in them bleeding money and labour and no small amount of corporate prestige on something that's not going to sell, if it isn't going to sell. Better to wait and see first.

True but it would be disappointing if DC doesn't get built as it's the only serious commercial orbital vehicle project other then Dragon V2 that I find exciting and innovative.


Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Rocket Science on 05/01/2015 01:22 am
Dream Chaser® Cargo System Launches on Atlas V Concept of Operation Video

Published on Apr 6, 2015
Sierra Nevada Corporation’s (SNC) Dream Chaser® Cargo System is a mission variant of the Dream Chaser Space System that exceeds all NASA cargo transportation requirements to the International Space Station (ISS). The Dream Chaser Cargo System utilizes a reusable, lifting-body spacecraft and is capable of transporting pressurized and unpressurized cargo concurrently - returning cargo and sensitive science payloads to a low-g and gentle runway landing.

https://youtu.be/uHJ2QV0nPEA
Ha! That's an Atlas V 552! That is an expensive (and quite powerful) LV. I would guess somewhere around 18.5tonnes to ISS injection orbit (350km at 51.6deg). That would require an enhanced Falcon 9. But I'm surprised since the the H-2B can barely put 16.5tonnes to that orbit.

Looking at the front end profile of this design, it appears that SNC is still looking at a Manned version of this craft.  Simplified curves on the upper surface would provide better aerodynamics and slightly lower mass, but would make it harder to convert to a manned version.
It was the same with all the aero work that went into the X-23/X-24A that was transferred into the X-38 program keeping the same moldline...
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: adrianwyard on 06/15/2015 05:38 pm
I just posted this news in the Update thread:

"Sierra Nevada Dream Chaser could make Huntsville the first commercial landing site for space craft"
http://forum.nasaspaceflight.com/index.php?action=profile;area=showposts;u=16824

I'm not sure what to make of this; it seems awfully premature. Perhaps in SNC's current CRS2 bid they claim cargo/science can be returned to Huntsville and so this is a good faith effort towards establishing it's practical.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: adrianwyard on 06/15/2015 06:02 pm
Anyone up for some revisionist history and wild speculation? If so, here's a question:

Would Virgin Galactic have been better off using a DC-derived design for SpaceShipTwo? i.e. suborbital air launched tourism? To my eyes it looks like a good fit, but I may be missing something:

+ The internal volume looks comparable (or perhaps larger if the SS2 cabin shrinks to 4 passengers as expected in order to accommodate engine changes.)
+ It's been designed - and tested - to fly in the same speed range and handle heating (and higher/faster/hotter of course).
+ More volume is dedicated to propulsion, so if SS2 can't make it to 100km, perhaps DC with the new Orbitec propanox engines could?

And the biggie:

+ It's a design that doesn't depend on breaking the craft in two during flight and then locking it back together before landing. (That's a bit harsh, but the fact is the design has already cost one life). While I understand that SS2 in feathered configuration can make it back to atmospheric flight altitudes with no RCS at all, the DC OML is also passively stable. (Tests showed very little RCS prop was needed during entry). So for my money this makes the DC shape the better design.

Since SNC were working closely with VG for a while, I suppose this must have occurred to someone involved before now. In actual history, SS2 was always going to derived from SS1 if that flew successfully, which of course it did. But if SS1 had had sufficient problems, would looking to the DC design have made sense, I wonder?
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: ChrisWilson68 on 06/15/2015 08:03 pm
Anyone up for some revisionist history and wild speculation? If so, here's a question:

Would Virgin Galactic have been better off using a DC-derived design for SpaceShipTwo? i.e. suborbital air launched tourism? To my eyes it looks like a good fit, but I may be missing something:

+ The internal volume looks comparable (or perhaps larger if the SS2 cabin shrinks to 4 passengers as expected in order to accommodate engine changes.)
+ It's been designed - and tested - to fly in the same speed range and handle heating (and higher/faster/hotter of course).
+ More volume is dedicated to propulsion, so if SS2 can't make it to 100km, perhaps DC with the new Orbitek propanox engines could?

And the biggie:

+ It's a design that doesn't depend on breaking the craft in two during flight and then locking it back together before landing. (That's a bit harsh, but the fact is the design has already cost one life). While I understand that SS2 in feathered configuration can make it back to atmospheric flight altitudes with no RCS at all, the DC OML is also passively stable. (Tests showed very little RCS prop was needed during entry). So for my money this makes the DC shape the better design.

Since SNC were working closely with VG for a while, I suppose this must have occurred to someone involved before now. In actual history, SS2 was always going to derived from SS1 if that flew successfully, which of course it did. But if SS1 had had sufficient problems, would looking to the DC design have made sense, I wonder?

DC is far too expensive to make sense as a sub-orbital tourism craft.  It was designed to be orbital, and different trade-offs are made for the very different requirements.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: ChrisWilson68 on 06/15/2015 08:12 pm
I just posted this news in the Update thread:

"Sierra Nevada Dream Chaser could make Huntsville the first commercial landing site for space craft"
http://forum.nasaspaceflight.com/index.php?action=profile;area=showposts;u=16824

I'm not sure what to make of this; it seems awfully premature. Perhaps in SNC's current CRS2 bid they claim cargo/science can be returned to Huntsville and so this is a good faith effort towards establishing it's practical.

It's meaningless PR.  This is some local politicians in the city of Huntsville making a joint announcement with SNC.  Of course local politicians love to see their names in the paper, and SNC wants to give the impression Dream Chaser isn't dead.  So there's something in it for SNC and there's something in it for the Huntsville politicians, and there's no actual commitment or cost to anyone.  And there's no substance.

By the way, here's the link to the original article, for those who don't want to go indirectly through all of adrianwyard's posts to find it:

http://www.al.com/news/index.ssf/2015/06/sierra_nevada_announcement.html
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: adrianwyard on 06/15/2015 10:50 pm
Anyone up for some revisionist history and wild speculation? If so, here's a question:

Would Virgin Galactic have been better off using a DC-derived design for SpaceShipTwo? i.e. suborbital air launched tourism? To my eyes it looks like a good fit, but I may be missing something:

+ The internal volume looks comparable (or perhaps larger if the SS2 cabin shrinks to 4 passengers as expected in order to accommodate engine changes.)
+ It's been designed - and tested - to fly in the same speed range and handle heating (and higher/faster/hotter of course).
+ More volume is dedicated to propulsion, so if SS2 can't make it to 100km, perhaps DC with the new Orbitek propanox engines could?

And the biggie:

+ It's a design that doesn't depend on breaking the craft in two during flight and then locking it back together before landing. (That's a bit harsh, but the fact is the design has already cost one life). While I understand that SS2 in feathered configuration can make it back to atmospheric flight altitudes with no RCS at all, the DC OML is also passively stable. (Tests showed very little RCS prop was needed during entry). So for my money this makes the DC shape the better design.

Since SNC were working closely with VG for a while, I suppose this must have occurred to someone involved before now. In actual history, SS2 was always going to derived from SS1 if that flew successfully, which of course it did. But if SS1 had had sufficient problems, would looking to the DC design have made sense, I wonder?

DC is far too expensive to make sense as a sub-orbital tourism craft.  It was designed to be orbital, and different trade-offs are made for the very different requirements.

Agreed you wouldn't take DC as spec'd for the Commercial Crew competition and use it for tourists. That's why I said "DC-derived". And by that I mean just the Outer Mold Line (and hence wind-tunnel testing). While DC was designed for the full 0-M25-0 it looks to me to be appropriate for what Virgin Galactic need too. You'd have to put nice big windows in the top fuselage, and roll upside down when at altitude. But aero/thermodynamically, it would have been an OK fit wouldn't it?
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: adrianwyard on 06/15/2015 10:54 pm
I just posted this news in the Update thread:

"Sierra Nevada Dream Chaser could make Huntsville the first commercial landing site for space craft"
http://forum.nasaspaceflight.com/index.php?action=profile;area=showposts;u=16824

I'm not sure what to make of this; it seems awfully premature. Perhaps in SNC's current CRS2 bid they claim cargo/science can be returned to Huntsville and so this is a good faith effort towards establishing it's practical.

It's meaningless PR.  This is some local politicians in the city of Huntsville making a joint announcement with SNC.  Of course local politicians love to see their names in the paper, and SNC wants to give the impression Dream Chaser isn't dead.  So there's something in it for SNC and there's something in it for the Huntsville politicians, and there's no actual commitment or cost to anyone.  And there's no substance.

By the way, here's the link to the original article, for those who don't want to go indirectly through all of adrianwyard's posts to find it:

http://www.al.com/news/index.ssf/2015/06/sierra_nevada_announcement.html

Truth be told, this was my first impression too. I don't begrudge SNC being good at playing the PR/spin game - it's a necessary part of the commercial/political landscape - but at some point the hardware needs to match the hype.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Rocket Science on 06/15/2015 11:06 pm
Anyone up for some revisionist history and wild speculation? If so, here's a question:

Would Virgin Galactic have been better off using a DC-derived design for SpaceShipTwo? i.e. suborbital air launched tourism? To my eyes it looks like a good fit, but I may be missing something:

+ The internal volume looks comparable (or perhaps larger if the SS2 cabin shrinks to 4 passengers as expected in order to accommodate engine changes.)
+ It's been designed - and tested - to fly in the same speed range and handle heating (and higher/faster/hotter of course).
+ More volume is dedicated to propulsion, so if SS2 can't make it to 100km, perhaps DC with the new Orbitek propanox engines could?

And the biggie:

+ It's a design that doesn't depend on breaking the craft in two during flight and then locking it back together before landing. (That's a bit harsh, but the fact is the design has already cost one life). While I understand that SS2 in feathered configuration can make it back to atmospheric flight altitudes with no RCS at all, the DC OML is also passively stable. (Tests showed very little RCS prop was needed during entry). So for my money this makes the DC shape the better design.

Since SNC were working closely with VG for a while, I suppose this must have occurred to someone involved before now. In actual history, SS2 was always going to derived from SS1 if that flew successfully, which of course it did. But if SS1 had had sufficient problems, would looking to the DC design have made sense, I wonder?

DC is far too expensive to make sense as a sub-orbital tourism craft.  It was designed to be orbital, and different trade-offs are made for the very different requirements.

Agreed you wouldn't take DC as spec'd for the Commercial Crew competition and use it for tourists. That's why I said "DC-derived". And by that I mean just the Outer Mold Line (and hence wind-tunnel testing). While DC was designed for the full 0-M25-0 it looks to me to be appropriate for what Virgin Galactic need too. You'd have to put nice big windows in the top fuselage, and roll upside down when at altitude. But aero/thermodynamically, it would have been an OK fit wouldn't it?
You missed this!
http://forum.nasaspaceflight.com/index.php?topic=36177.0
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: adrianwyard on 06/15/2015 11:26 pm
Actually I did see that thread: you have at least one interesting video I'd not seen before.

I assume since you started that one that you agree the DC shape is suitable for suborbital applications? How would you rate it compared to SS2?

Over on the Blue Origin threads there are people vigorously defending the Blue suborbital design as superior/safer than the VG SS2. I wonder how a (fictional) DC-shaped suborbital design would stand up to that critique. I'd probably prefer to fly on DC than SS2, and prefer to land on a runway than do the Soyuz-style crash-landing that Blue plan. I bet people would pay big money to fly weightless over London, Paris, Dubai, etc. which is something SS2/DC could do but probably not Blue.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: adrianwyard on 06/16/2015 04:32 pm
And there’s video of the announcement: https://www.youtube.com/watch?v=Pnkax3335Bg

I’m afraid I couldn’t help but chuckle at the compounded weasel words in the intro: They announced:

1] plans to…
2] initiate…
3] preliminary studies…
4] to assess feasibility…

of landing at Huntsville.

Politician-speak aside, I was right in that this announcement is connected with their CRS2 bid.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Patchouli on 06/18/2015 02:09 am

Agreed you wouldn't take DC as spec'd for the Commercial Crew competition and use it for tourists. That's why I said "DC-derived". And by that I mean just the Outer Mold Line (and hence wind-tunnel testing). While DC was designed for the full 0-M25-0 it looks to me to be appropriate for what Virgin Galactic need too. You'd have to put nice big windows in the top fuselage, and roll upside down when at altitude. But aero/thermodynamically, it would have been an OK fit wouldn't it?


Originally back in the SpaceDev days they planned to start out with suborbital flights before flying orbital.
A simplified variant of Dream Chaser would likely would be much cheaper per flight then Blue Origin's New Shepard vehicle.
In some ways a sub orbital DC is everything SS2 should have been.
 Though SS2 and Lynx might still be cheaper once they fully in operation but unlike them SNC has a direct evolutionary path to orbital flight.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: QuantumG on 06/18/2015 02:13 am
Though SS2 and Lynx might still be cheaper once they fully in operation but unlike them SNC has a direct evolutionary path to orbital flight.

I don't think evolutionary is the right word. Retroactive?

The long term goals of VG and XCOR is fully reusable orbital systems. They've got their work cut out for them, but I've never heard SNC talk about that sort of thing.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: ChrisWilson68 on 06/18/2015 02:51 am

Agreed you wouldn't take DC as spec'd for the Commercial Crew competition and use it for tourists. That's why I said "DC-derived". And by that I mean just the Outer Mold Line (and hence wind-tunnel testing). While DC was designed for the full 0-M25-0 it looks to me to be appropriate for what Virgin Galactic need too. You'd have to put nice big windows in the top fuselage, and roll upside down when at altitude. But aero/thermodynamically, it would have been an OK fit wouldn't it?


Originally back in the SpaceDev days they planned to start out with suborbital flights before flying orbital.
A simplified variant of Dream Chaser would likely would be much cheaper per flight then Blue Origin's New Shepard vehicle.
In some ways a sub orbital DC is everything SS2 should have been.
 Though SS2 and Lynx might still be cheaper once they fully in operation but unlike them SNC has a direct evolutionary path to orbital flight.

I don't see why a sub-orbital Dream Chaser would be "much cheaper per flight" than New Shepard.

Of course when we talk about "sub-orbital Dream Chaser" we're not really talking about a specific, fleshed-out plan -- just a vague idea that the outer mold line of Dream Chaser will be used in a reusable vehicle (and it's probably fairer to call it a "sub-orbital HL-20" if it's only keeping the outer mold line, since Dream Chaser took that from HL-20).  Will it have a booster stage?  What sort of engines?  None of those most basic questions have been answered.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Mike Harris-Stone on 06/18/2015 03:58 am
Actually, Spacedev did have a plan and a flight profile to fly the DC for suborbital space tourism.

The vehicle would have launched as a single stage using it's internal hybrid rocket motors.

If I understand right, the problem they ran into is this flight profile involved the occupants pulling significant Gs.  Not very good for tourists.  So they actually created a new company, (Benson Space Company) focused only on tourism that was going to build a whole new rocketplane that looked a bit like a T-38.  (That's right a T-38 jet trainer.)  But then Jim Benson died and those plans ended.

http://www.space.com/3844-benson-space-unveils-dream-chaser-design.html

Spacedev kept DC going as an orbital spacecraft and then were bought by Sierra Nevada.

The HL-20 was always designed as an orbital spacecraft.  I believe a lifting body does not fly like an airplane...i.e. you can't put an engine in one and just take off.  What it does instead is land like an airplane.  In this way it's much more like a capsule than the shuttle was.  Also, because it only generates lift at high angles of attack...you don't have that much of an issue with bending moment (correct me if I'm saying this wrong...I'm not an engineer) when launching on a vertical stack.

I really don't think the shape is very good for suborbital flight of tourists.  The advantage of SS2's shuttlecock approach is that the vehicle can just fall, use drag to slow down and then eventually acquire flight.

The advantage of landing like a plane is it's gentle, easy and very well understood.

Landing propulsively seems like it's still very early stages as far as safety and comfort go.

Landing by parachute is rough.  Period.  Not something I'd want to subject my Mom to and probably pretty bad for tourists unless they are the "pay to climb Everest type" who don't mind serious hardship and risk.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Patchouli on 06/18/2015 04:49 am

I don't see why a sub-orbital Dream Chaser would be "much cheaper per flight" than New Shepard.

Of course when we talk about "sub-orbital Dream Chaser" we're not really talking about a specific, fleshed-out plan -- just a vague idea that the outer mold line of Dream Chaser will be used in a reusable vehicle (and it's probably fairer to call it a "sub-orbital HL-20" if it's only keeping the outer mold line, since Dream Chaser took that from HL-20).  Will it have a booster stage?  What sort of engines?  None of those most basic questions have been answered.


It's pretty easy to see why it would be cheaper.

No parachutes to be inspected and repacked for a nominal flight.
These are not like what's used for skydiving but more so what's used for dropping cargo or shuttle SRB recovery.
Nor would it need as many pyro devices replaced each flight for separation,chute deployment, and landing.
It does not have the cost of a hydrolox rocket associated with it.
Recovery is just having a pushback with a cart get it at the end of the runway.
No need for cranes or heavy off road vehicles.
Actually, Spacedev did have a plan and a flight profile to fly the DC for suborbital space tourism.

The vehicle would have launched as a single stage using it's internal hybrid rocket motors.

If I understand right, the problem they ran into is this flight profile involved the occupants pulling significant Gs.  Not very good for tourists.  So they actually created a new company, (Benson Space Company) focused only on tourism that was going to build a whole new rocketplane that looked a bit like a T-38.  (That's right a T-38 jet trainer.)  But then Jim Benson died and those plans ended.

http://www.space.com/3844-benson-space-unveils-dream-chaser-design.html

Spacedev kept DC going as an orbital spacecraft and then were bought by Sierra Nevada.

The HL-20 was always designed as an orbital spacecraft.  I believe a lifting body does not fly like an airplane...i.e. you can't put an engine in one and just take off.  What it does instead is land like an airplane.  In this way it's much more like a capsule than the shuttle was.  Also, because it only generates lift at high angles of attack...you don't have that much of an issue with bending moment (correct me if I'm saying this wrong...I'm not an engineer) when launching on a vertical stack.

I really don't think the shape is very good for suborbital flight of tourists.  The advantage of SS2's shuttlecock approach is that the vehicle can just fall, use drag to slow down and then eventually acquire flight.

The advantage of landing like a plane is it's gentle, easy and very well understood.

Landing propulsively seems like it's still very early stages as far as safety and comfort go.

Landing by parachute is rough.  Period.  Not something I'd want to subject my Mom to and probably pretty bad for tourists unless they are the "pay to climb Everest type" who don't mind serious hardship and risk.

True the sub orbital variant was first.
https://www.youtube.com/watch?v=hkMSrT8uySc

The original OML for Dream Chaser was the X34 shape.
https://www.youtube.com/watch?v=mT_WR4P9mzs

The BSC space plane shape was kinda like a combination of the X-1 and X-15 it had a very Flash Gordon sorta look to it.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: docmordrid on 06/18/2015 08:34 am
More like the spacecraft in When Worlds Collide
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Rocket Science on 06/19/2015 05:43 pm
Actually I did see that thread: you have at least one interesting video I'd not seen before.

I assume since you started that one that you agree the DC shape is suitable for suborbital applications? How would you rate it compared to SS2?

Over on the Blue Origin threads there are people vigorously defending the Blue suborbital design as superior/safer than the VG SS2. I wonder how a (fictional) DC-shaped suborbital design would stand up to that critique. I'd probably prefer to fly on DC than SS2, and prefer to land on a runway than do the Soyuz-style crash-landing that Blue plan. I bet people would pay big money to fly weightless over London, Paris, Dubai, etc. which is something SS2/DC could do but probably not Blue.
SS2 feather “is a solution to a non existing problem” and just adds another failure mode. Well Benson intended it for sub-orbital tourism so real problem for them to produce a variant of their orbital DC. I was going through my paper copy of last month’s Aviation Week and read an interesting article of why SNC isn’t giving up on Dream Chaser.

http://aviationweek.com/space/sierra-nevada-continues-push-its-dream-chaser
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: freakdog on 06/28/2015 04:17 pm
Oh hate to say it, but after the last few weeks, it seems like with the proven capability of the Atlas 5, the comparative costs, and the obviously 'going to slip to the right' schedule, that DreamChaser was a pretty viable option after all.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: winkhomewinkhome on 06/28/2015 04:48 pm
Oh hate to say it, but after the last few weeks, it seems like with the proven capability of the Atlas 5, the comparative costs, and the obviously 'going to slip to the right' schedule, that DreamChaser was a pretty viable option after all.

With all due respect, for as much as I loved the HL-20/Dream Chaser concept, that statement is about as faulty as they come. Argh...
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: freakdog on 06/28/2015 05:44 pm
900 million less than Boeing and on a proven launch vehicle with a 0 percent failure rate and a schedule that was bound to slip.  What's to criticize about that statement?
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: winkhomewinkhome on 06/28/2015 09:24 pm
900 million less than Boeing and on a proven launch vehicle with a 0 percent failure rate and a schedule that was bound to slip.  What's to criticize about that statement?
Again - I liked Dream Chaser, and yes, I agree, it was "potentially" a more cost effective path than Boeing - but both, until they fly are unproven.  Yes, Atlas has a spotless flight record, thankfully, thus far, but to transfer its reliability record to whatever rides atop it, is, as stated, faulty.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: freakdog on 07/03/2015 01:48 am
Again - I liked Dream Chaser, and yes, I agree, it was "potentially" a more cost effective path than Boeing - but both, until they fly are unproven.  Yes, Atlas has a spotless flight record, thankfully, thus far, but to transfer its reliability record to whatever rides atop it, is, as stated, faulty.
You cannot say what it has but you can say what it doesn't have--a 5% historical total LOV rate due to the LV failures.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: davey142 on 07/03/2015 02:04 am
Again - I liked Dream Chaser, and yes, I agree, it was "potentially" a more cost effective path than Boeing - but both, until they fly are unproven.  Yes, Atlas has a spotless flight record, thankfully, thus far, but to transfer its reliability record to whatever rides atop it, is, as stated, faulty.
You cannot say what it has but you can say what it doesn't have--a 5% historical total LOV rate due to the LV failures.
The safest vehicle is one that doesn't leave the pad. And the safest spacecraft is the one that isn't built.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: adrianwyard on 07/08/2015 11:09 pm
...

 I was going through my paper copy of last month’s Aviation Week and read an interesting article of why SNC isn’t giving up on Dream Chaser.

http://aviationweek.com/space/sierra-nevada-continues-push-its-dream-chaser

Would you be willing to summarize for those of us who are too cheap to subscribe?
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: BrianNH on 07/09/2015 12:56 pm
Note: the article was published on April 29th.

The article states that the test article that crashed is being repaired and will have another test flight by the end of the year (funded by CCiCap).  There is another "iron bird" model "running all seven of the lifting body's simulated control surfaces through their paces with three flight computers that are also linked to a single-seat simulator down the hall."

The first orbital vehicle composite structure is due to arrive soon from Lockheed Martin.

Quote
“What we’re trying to do is continue to move the vehicle forward, albeit at a slower pace than if we had won the crew competition, but moving it forward in its critical elements so that we have a chance to be able to do test flights with the atmospheric vehicle and then eventually a launch test flight,” says Mark Sirangelo, who heads the company’s space systems unit. “But clearly we have to get a client in order to do that.”

There is a quote from Steve Lindsey, Sierra Nevada’s senior director and co-program manager for space exploration systems, about science return cargo wanting a "gentle" return to gravity that was lost with the retirement of the shuttles.  He also notes that DC can carry 5,500 kg of cargo to the station.  He notes that using fewer cargo trips with more payload per trip minimizes the impact on station operations due to crew support needed.  By allowing twice the requested cargo carrying capacity, they can reduce the number of launches required and thus overall costs.

They have removed anything crew related, including windows, to save weight. 

Quote
Riding behind the original lifting-body, which duplicates the mold line NASA developed for its HL-20 experimental vehicle, would be a separate cargo module to carry more pressurized cargo and unpressurized cargo in three off-the-shelf ISS Flight Releasable Attachment Mechanisms (Frams) supplied by Teledyne Brown Engineering.

The cargo module would be disposed of on the way back, allowing DC to dispose of trash at the same time that cargo is returned to a runway.

DC would dock autonomously to one of the crew vehicle PMAs, rather then the cargo ports, which require the station crew to use the robotic arm to attach and detach the cargo ship.  No special gear would be needed by people opening the DC after landing because no toxic hypgolics are used - nitrous oxide and propane are used instead.

The wings will fold to fit into a 5 meter fairing to fit on an Atlas V, Ariane 5, and "perhaps other launchers as well". 

Sierra Nevada says that the Germans are interested in DC for robotic satellite servicing and retrieval of defunct spacecraft.  They are working with Japan to develop a free-flying lab version of DC (similar to DragonLab).  They are still working with Stratolaunch to develop a subscale version for launch.


Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: adrianwyard on 07/09/2015 04:14 pm
@BrianNH: Thanks very much for doing that.

Sorry to be cynical but this sounds like just a continuation of the messages we’ve heard from SNC over the last few years, which I think are intended just to convince people with fat checkbooks that they are a legit player in the spacecraft business.

When they say the Germans are interested in using DC for satellite retrieval, to the uncritical ear that sounds like a deal with DLR analogous to NASA CRS could be in the wings. Which would mean the project can go forwards: great news! But in reality how would that even work? Where’s the payload bay? Or grapple/robotic-arm hardware, and last but not least: business case and real-world usage example? At best it’s a paper study about very general potential future capabilities, and likely just encouraging words from DLR via MOU paperwork.

I’ve been roundly criticized before now for being a DC amazing people, and that’s largely true: I’ve come to the opinion that HL-20/DC is an ingenious aerodynamic design that deserves a chance to demonstrate the advantages it has over capsule designs. So I’m very glad to hear the second flight test is going ahead.

If that flight goes well, SNC will be in an interesting position: in possession of a vehicle that’s designed for orbital/hypersonic speed that’s been flight-tested (with an automated flight control system) and wind-tunnel tested to high Mach.

Assuming no-one comes forward with money to complete the project to orbital capability, what could be done with this?

Were XCOR, Virgin Galactic, and Blue, not already far along with their suborbital tourism projects I’d suggest SNC could keep the project alive by entering this market. Propulsion and air-launch are big open questions. But on paper DC would have some advantages over the other three: if we magic-up some beefy propulsion DC’s design can go further, faster, offer more weightless time, and then endure more heating than XCOR and SS2. It could perhaps do point-to-point suborbital of several hundred miles. Blue could conceivably do this too, but only DC could launch from different locations offering better views to the tourists.

But in reality this seems just slightly more likely than satellite retrieval for the Germans.

Any other ideas?
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: TrevorMonty on 07/09/2015 09:11 pm
The Japanese partnership may hold most hope for DC, especially if it is launching on new lower cost H3 LV.
This partnership would give Japan its own HSF capability.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: BrianNH on 07/10/2015 03:02 am
The article just states that JAXA is using their expertise in "orbital laboratory design" to help Sierra with the lab version.  It doesn't indicate if they are interested in using it for that purpose. 
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: yg1968 on 07/10/2015 01:33 pm
They are still working with Stratolaunch to develop a subscale version for launch.

I am a bit skeptical about that. Stratolaunch indicated that anything crew or rocket related was on hold. I am hoping that Paul Allen will eventually invest in DC but I don't see any reasons to invest in a subscale DC if there is no Stratolaunch rocket that can carry it.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: BrianNH on 07/10/2015 02:42 pm
Keep in mind that the article was written in late April.  Things may have changed since then.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: DatUser14 on 07/14/2015 12:38 am
SNC is getting fairly desperate, they just sent a KSP modder named artwhaley a cease and desist notice for his dream chaser KSP mod. Hopefully he can get it cleared up soon.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: ChrisWilson68 on 07/14/2015 01:20 am
@BrianNH: Thanks very much for doing that.

Sorry to be cynical but this sounds like just a continuation of the messages we’ve heard from SNC over the last few years, which I think are intended just to convince people with fat checkbooks that they are a legit player in the spacecraft business.

When they say the Germans are interested in using DC for satellite retrieval, to the uncritical ear that sounds like a deal with DLR analogous to NASA CRS could be in the wings. Which would mean the project can go forwards: great news! But in reality how would that even work? Where’s the payload bay? Or grapple/robotic-arm hardware, and last but not least: business case and real-world usage example? At best it’s a paper study about very general potential future capabilities, and likely just encouraging words from DLR via MOU paperwork.

I agree, it's all hype without substance.

If DLR, or any other government entity, were serious about paying significant money for Dream Chaser, it would be going through the appropriations process and we would hear about it.  DLR and every other government space agency has very limited funding and decisions about how to use that funding are always political and in the news.  That would be true no matter what the money was to be spent on, but particularly in a case like this where the money would be spent outside the country spending it.  There would be a huge outcry by the domestic Germany space industry if there were any hint the German space agency was actually serious considering spending big bucks on a U.S. company.  Just look at all the fighting over who gets what money on Ariane or any ESA project.  They're always careful that they money going to the industry in each country matches the money that country is contributing.

I’ve been roundly criticized before now for being a DC amazing people, and that’s largely true: I’ve come to the opinion that HL-20/DC is an ingenious aerodynamic design that deserves a chance to demonstrate the advantages it has over capsule designs. So I’m very glad to hear the second flight test is going ahead.

I wouldn't get too excited just yet.  It's just words from SNC.  We haven't seen any evidence yet they are actually spending the money to make that flight happen.  SNC has already promised various things with respect to Dream Chaser that have not turned out to have happened.

If that flight goes well, SNC will be in an interesting position: in possession of a vehicle that’s designed for orbital/hypersonic speed that’s been flight-tested (with an automated flight control system) and wind-tunnel tested to high Mach.

Actually, no, they won't.  The second flight test, if it happens, will again be of a unit only designed for slow-speed glide testing.  It won't actually be capable of orbital or hypersonic speed.

Remember, they've only gotten a small fraction of their budgeted development costs for Dream Chaser.  It's not realistic to expect a vehicle that is capable of orbital or hypersonic speed without several times as much money as has already been spent on the Dream Chaser program.

Assuming no-one comes forward with money to complete the project to orbital capability, what could be done with this?

Not much.  They could take people for slow-speed gliding landings, and that's about it.

Remember, this vehicle was only designed to test the low speed gliding handling of the real Dream Chaser.  It matches the outer lines of the planned Dream Chaser and has its control surfaces, but that's about it.

Were XCOR, Virgin Galactic, and Blue, not already far along with their suborbital tourism projects I’d suggest SNC could keep the project alive by entering this market. Propulsion and air-launch are big open questions. But on paper DC would have some advantages over the other three: if we magic-up some beefy propulsion DC’s design can go further, faster, offer more weightless time, and then endure more heating than XCOR and SS2. It could perhaps do point-to-point suborbital of several hundred miles. Blue could conceivably do this too, but only DC could launch from different locations offering better views to the tourists.

But in reality this seems just slightly more likely than satellite retrieval for the Germans.

Yeah, both sub-orbital Dream Chaser and German satellite retrieval are pretty unlikely, and for the same reason: nobody with the money to pay the high costs of either appears likely to do so.

Remember, Dream Chaser isn't some nearly-complete system that needs only a bit more investment to be operational.  It's a system that has only received around 10% of its projected budget.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: yg1968 on 07/14/2015 04:25 pm
SNC is getting fairly desperate, they just sent a KSP modder named artwhaley a cease and desist notice for his dream chaser KSP mod. Hopefully he can get it cleared up soon.

I guess that he should just call it a HL-20 model to get them off his back.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: notsorandom on 07/14/2015 05:30 pm
SNC is getting fairly desperate, they just sent a KSP modder named artwhaley a cease and desist notice for his dream chaser KSP mod. Hopefully he can get it cleared up soon.
If that is true then they have really shot themselves in the foot from a PR standpoint. Engaging with fans is in any company's best interest.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Rocket Science on 07/14/2015 06:08 pm
SNC is getting fairly desperate, they just sent a KSP modder named artwhaley a cease and desist notice for his dream chaser KSP mod. Hopefully he can get it cleared up soon.
If that is true then they have really shot themselves in the foot from a PR standpoint. Engaging with fans is in any company's best interest.
Only if those fans have a couple of B's in their back pockets...
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: ChrisWilson68 on 07/14/2015 06:13 pm
SNC is getting fairly desperate, they just sent a KSP modder named artwhaley a cease and desist notice for his dream chaser KSP mod. Hopefully he can get it cleared up soon.
If that is true then they have really shot themselves in the foot from a PR standpoint. Engaging with fans is in any company's best interest.
Only if those fans have a couple of B's in their back pockets...

I don't agree.  Being popular among KSP users can only help with recruiting, not just for Dream Chaser, but for SNC in general.

Also, just in general a more favorable opinion of a company is going to show in the attitude people take towards it in discussion forums, and people in NASA and other companies will be influenced by it.  Ultimately, some of those people will be decision makers somewhere down the line and, subconsciously or not, general impressions of a company will influence whether decision makers choose to do business with one company or another.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: adrianwyard on 07/14/2015 06:21 pm
My theory is SNC's legal dept. just got bored. Mark Sirangelo certainly comes across as the kind of guy that would see the value of KSP, if not play it himself.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: ChrisWilson68 on 07/14/2015 07:25 pm
My theory is SNC's legal dept. just got bored. Mark Sirangelo certainly comes across as the kind of guy that would see the value of KSP, if not play it himself.

Yeah, it does seem more like a decision a low-level, not-too-bright lawyer would make, not something that comes down from upper-level management.  Or maybe a law firm seeing a chance for more billable hours.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: A_M_Swallow on 07/15/2015 12:42 am
SNC is getting fairly desperate, they just sent a KSP modder named artwhaley a cease and desist notice for his dream chaser KSP mod. Hopefully he can get it cleared up soon.
If that is true then they have really shot themselves in the foot from a PR standpoint. Engaging with fans is in any company's best interest.
Only if those fans have a couple of B's in their back pockets...

Or the fans have sufficient votes to get a senator interested.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: NovaSilisko on 07/15/2015 01:54 am
SNC is getting fairly desperate, they just sent a KSP modder named artwhaley a cease and desist notice for his dream chaser KSP mod. Hopefully he can get it cleared up soon.

Can I get a source/link for this? I feel compelled to know more about such stupidity.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: arachnitect on 07/15/2015 02:00 am
SNC is getting fairly desperate, they just sent a KSP modder named artwhaley a cease and desist notice for his dream chaser KSP mod. Hopefully he can get it cleared up soon.

Can I get a source/link for this? I feel compelled to know more about such stupidity.

http://forum.kerbalspaceprogram.com/threads/100445-Dreamer-SNC-Dreamchaser-Mod-V1-2-UPDATED%21-Now-with-%28some%29-FAR-support%21?p=2050438&viewfull=1#post2050438
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Patchouli on 07/16/2015 05:18 am

Yeah, it does seem more like a decision a low-level, not-too-bright lawyer would make, not something that comes down from upper-level management.  Or maybe a law firm seeing a chance for more billable hours.


He should write someone higher up at SNC for permission to release the mod as I think they probably would say it's ok and who knows maybe they'll let that lawyer go.
If I was in Eren Ozmen's position I'd personally fire that lawyer as stuff like this is very bad PR.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: kato on 07/19/2015 11:48 am
When they say the Germans are interested in using DC for satellite retrieval, to the uncritical ear that sounds like a deal with DLR analogous to NASA CRS could be in the wings. Which would mean the project can go forwards: great news! But in reality how would that even work? Where’s the payload bay? Or grapple/robotic-arm hardware, and last but not least: business case and real-world usage example? At best it’s a paper study about very general potential future capabilities, and likely just encouraging words from DLR via MOU paperwork.
The satellite servicing mission was identified as a possible mission for DC during DC4EU. The business case exists with DLR, with the DEOS mission slated to launch in 2017 as a testing and R&D article in this particular field. DEOS and introducing on-orbit servicing for commercial customers is explicitly part of Germany's official space strategy.

OHB, SNC's German partner, originally did the DEOS preliminary mission design and got the main development contract, but lost the final build contract to Airbus. Pushing DC as a possible, more capable platform that could be available through OHB and its partner is mostly about positioning them for future business.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: adrianwyard on 07/19/2015 10:31 pm
Thanks for that additional info. I found the following info on DEOS: http://robotics.estec.esa.int/ASTRA/Astra2011/Presentations/Plenary%202/04_wolf.pdf

Sadly, the fact that there are standalone satellite servicing demonstrations such as DEOS planned doesn't mean there's a automatically a viable business case for using (and first completing) DC for that role.

My guess is that satellite deorbiting is a service that will find paying customers one day, but DC does not seem to be the right tool for that job.

And even for servicing I'm not really sure how DC would be notably more capable than other options. Assuming there would be a DC launch for each satellite that's serviced you have to wonder if that launch would not be better spent launching a new satellite.

Even if we just state that DC WILL be used for satellite servicing and ignore the money, there will have to be modifications made. The best option I can imagine is replacing the rear docking port with a simple door into a depressurized area that contains a cylindrical caddy of arms, parts, tools etc. that is extended out of the hatch once on orbit. But this (non-trivial) approach could be done just as easily on Dragon 2 or CST-100.

Am I missing something? Is there some way in which DC is a desirable platform for servicing?
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: kato on 07/20/2015 04:10 pm
Sadly, the fact that there are standalone satellite servicing demonstrations such as DEOS planned doesn't mean there's a automatically a viable business case for using (and first completing) DC for that role.
Yeah, the business case is more this quote from the official German Space Strategy (http://www.bmwi.de/English/Redaktion/Pdf/space-strategy,property=pdf,bereich=bmwi2012,sprache=en,rwb=true.pdf) (link in English; see page 13) as an objective of Expanding Strategic Space Expertise:

Quote
On-orbit satellite servicing will open up a new dimension for the commercial space sector, too: in future, robots will be responsible for the refuelling, servicing, repair, and controlled disposal of satellites in orbit, enabling operators to manage entire satellite fleets. In this way, it will be possible also to address the growing problem of space debris and improve the sustainability of space activities.

That means offering a solution - through a partner - can provide business of some kind, even if it's just in further studies evaluating its effective usability.

As for deorbiting, DC - or another platform - could also simply be used to attach a deorbit sail to larger defunct hardware.

Am I missing something? Is there some way in which DC is a desirable platform for servicing?
In this article/interview (http://www.satellitetoday.com/launch/2015/03/31/sierra-nevada-corporation-details-future-dream-chaser-mission-concepts/) SNC highlighted the fact that DC could perform multiple "servicing side-missions" in each flight. It also sounds more like crewed catch-repair-release missions along the lines of what has been done with STS a couple times. This of course possibly offers some advantages in handling over DEOS or other "capture" approaches for servicing or deorbiting since those models use pretty much anything to capture their target with up to harpoons proposed for this purpose.

Beyond that, I could at most see a certain utility for "soft return" of samples from experimental microgravity production performed onboard satellites, or of exchanged parts for failure analysis.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: adrianwyard on 07/21/2015 05:36 pm
Hi kato, and thanks again for helpful links. If you follow this thread into the past you'll find lots of enthusiasm for DC variants - many from me - but these all assumed that the starting point was a functional (i.e. funded and soon to be flying) crewed Dream Chaser. I'll include a couple of posts about variants below in which I advocate for adding a pressure bulkhead behind the cockpit, etc. You may enjoy the conversation before and after these.

The problem facing our friends at SNC at the moment is finding an 'anchor tenant'/business case that will (help) fund the completion of *any* variant. The best hope is CRS-2, but I'm afraid SpaceX and/or Orbital-ATK seem like obvious choices for NASA.


If we're allowed to imagine follow-on vehicle variants then a 'mini-cargo-bay/RMS' equipped DC blows the others away.

no, because the others can have similar variants and so there is no advantage.

Nope, not similar. I agree all could manage a simple EVA (tap the JWST) mission, but 'Servicing DC' with a cargo bay beats the others because:

+ Can bring back unpressurized cargo.
+ Brings back RMS (unlike Dragon proposal).
+ Readily allows for the addition of a suitport from the cabin into the cargo bay, so no need to depressurize cabin. This allows for shirtsleeves IVA crew-member assistance. http://en.wikipedia.org/wiki/Suitport
+ Has more cockpit window area for IVA to see worksite.
+ If suitport is not used, has a smaller pressurized cabin volume - less consumables needed for repress after EVA.

It would be an extremely valuable satellite that could justify an Atlas V launch, and a throw-away mission module/air-lock. And as mentioned before you can't abort with the module attached (but then perhaps you could launch with it disconnected, and hard-mate once in orbit. This could be done for all towed packages)

In the press conference they mentioned add-on mission objectives to an ISS crew change flight which makes sense, but with this type of mission module attached you can't dock to the ISS.

I believe EVA on all spacecraft after the Shuttle requires putting everyone in suits and depressurising the entire cabin. This seems like a step backwards especially with larger crews. We're already in the realm of sci-fi speculation here, so how about building a suitport into the upper surface of the DC behind a mini payload bay door? That would make it reusable.

http://en.wikipedia.org/wiki/Suitport

But back to near-term reality: how strong is the case for satellite servicing missions at all? And if there is one, which of the proposed spacecraft is most suited?

Returning to speculation on a Cargo/Servicing Dream Chaser:

Given how old the attached graphic is, and how easy these things are to generate, we have to keep plenty of grains of salt handy. Nevertheless, Mark Sirangelo has said servicing is a mission for Dream Chaser so it's interesting to guess how this might work.

In a previous post I suggested an airlock could be installed in the rear tunnel, and the upper stage adapter could house servicing-related equipment. It turns out these ideas were considered for the HL-42 (42% larger than HL-20). See http://www.astronautix.com/craft/hl42.htm. For some reason it didn't bother them that the 'towed package' was back next to the OMS engines...

As far as DC goes, I've changed my mind on these. If we assume that this graphic is about right, and the pressure bulkhead can easily be moved forward to open up a mini cargo bay, here are some observations.

+ We now have a place to house the replacement parts uphill, the robotic arm can be safely placed within the bay, and the system has the ability to return parts.

+ Such a craft could only visit the ISS unmanned as the crew can't get to the rear hatch.

+ If built, this would be the only way to return unpressurized cargo from the ISS (although Dragon and HTV can bring it up.)

+ For EVA you'd probably just depressurize the (smaller) cabin area. If having an IVA crewmember in shirt-sleeves during the EVA was valuable, then you'd repressurize the cabin immediately, and have to depress/repressurize to get the EVA crew back in. While this is wasteful, the extra O2 would surely be less mass than an airlock.

+ Or, if the design was matured in time, Dream Chaser would be a great application for a suitport. http://en.wikipedia.org/wiki/Suitport
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: kato on 07/25/2015 08:43 am
What springs to mind - regarding the "throwaway module" mentioned in that 2014 post that could be done with an extra bulkhead on the DC - is:

Why not build that extra module and leave it in orbit? DC could dock to it after leaving ISS (or on separate flights if someone pays for that) and once docked gain an airlock (and stowed-there spacesuits), extra power supply and mission-specific attachments (like a robotic arm).
This module, for OOS/ADR missions that do not require EVA, could probably also function unmanned; for missions requiring a human touch customer has to spend a couple million for a DC to go over (or a couple hundred if it's an urgent requirement).

Of course we still need to somehow uniquely identify that with DC or it would be rather general. Perhaps a modified cargo module to refuel the free-flyer. The bonus point in it all is that the basic DC would be usable as-is in any case; no variants needed. If one wants to give it an extra sales point, then to a limited extent this module could relatively cheaply perform commercial long-term research in space, serviced as a free-flyer by the visiting DC. This free-flyer module wouldn't have to be anything large, a few tons at most. Could perhaps be derived from the cargo module SNC is planning anyway.

If we only speculate, the free-flyer module could draw heavily on technical cooperation with e.g. Germany and Italy as the two prominent European manned spaceflight proponents. Likely wouldn't yield funding for DC, but could yield a contract that can still be portrayed as anchor tenants.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Jim on 07/25/2015 12:59 pm
Again, DC doesn't have any advantage over other vehicles for spacecraft servicing.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: yg1968 on 07/25/2015 03:42 pm
Again, DC doesn't have any advantage over other vehicles for spacecraft servicing.

One of the DC variants has an arm (made by MDA).
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: adrianwyard on 07/25/2015 05:58 pm
What springs to mind - regarding the "throwaway module" mentioned in that 2014 post that could be done with an extra bulkhead on the DC - is:

Why not build that extra module and leave it in orbit? DC could dock to it after leaving ISS (or on separate flights if someone pays for that) and once docked gain an airlock (and stowed-there spacesuits), extra power supply and mission-specific attachments (like a robotic arm).
This module, for OOS/ADR missions that do not require EVA, could probably also function unmanned; for missions requiring a human touch customer has to spend a couple million for a DC to go over (or a couple hundred if it's an urgent requirement).

Of course we still need to somehow uniquely identify that with DC or it would be rather general. Perhaps a modified cargo module to refuel the free-flyer. The bonus point in it all is that the basic DC would be usable as-is in any case; no variants needed. If one wants to give it an extra sales point, then to a limited extent this module could relatively cheaply perform commercial long-term research in space, serviced as a free-flyer by the visiting DC. This free-flyer module wouldn't have to be anything large, a few tons at most. Could perhaps be derived from the cargo module SNC is planning anyway.

If we only speculate, the free-flyer module could draw heavily on technical cooperation with e.g. Germany and Italy as the two prominent European manned spaceflight proponents. Likely wouldn't yield funding for DC, but could yield a contract that can still be portrayed as anchor tenants.

I don't believe this is practical as the chances of the module being in a convenient orbit for the next mission are very, very slim. Space as they say, is big. Plane changes are costly in terms of propellant.

My bet is that satellite servicing will be best done telerobotically, from a SEP powered spacecraft (that could take weeks or months to reach the next satellite on the maintenance schedule). Robots are more patient than humans. :-)

What SNC need is a true anchor tenant - not a list of potential uses and customers, however legitimate they may be. Such an anchor tenant needs the services so badly they can justify enabling the completion of the Dream Chaser. (E.g. NASA absolutely needs a way to get crew and cargo to the ISS).
_____
In an alternate universe where DC was flying and the Hubble Telescope had just been launched with botched optics, then I could see a manned repair mission concept being put together to save a priceless national asset. But this is sadly fiction.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Jim on 07/25/2015 09:31 pm
Again, DC doesn't have any advantage over other vehicles for spacecraft servicing.

One of the DC variants has an arm (made by MDA).

Arms can be added to other space craft.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Todd Martin on 07/25/2015 09:49 pm
Again, DC doesn't have any advantage over other vehicles for spacecraft servicing.

DC has an interior volume which is cylindrically shaped, allowing an airlock to be placed between the flight controls and the rear hatch.  This allows EVA without depressurizing the entire cabin, so crew can assist the EVA in a shirt sleeves environment.  I don't believe any of the capsules provide this feature without a separate service module.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Jim on 07/25/2015 09:59 pm
DC has an interior volume which is cylindrically shaped, allowing an airlock to be placed between the flight controls and the rear hatch.  This allows EVA without depressurizing the entire cabin, so crew can assist the EVA in a shirt sleeves environment.  I don't believe any of the capsules provide this feature without a separate service module.

So what?  Adding an airlock or adding a separate module, same thing.  it is a change from the baseline vehicle and not an inherent capability.  Servicing can be designed into any of the vehicles.

Anyways, DC has a greater drawback, rendezvous and docking the rear with no direct eyes on the target.  Even with televisions cameras, the physical cues are reversed.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Rocket Science on 07/26/2015 12:25 am
DC has an interior volume which is cylindrically shaped, allowing an airlock to be placed between the flight controls and the rear hatch.  This allows EVA without depressurizing the entire cabin, so crew can assist the EVA in a shirt sleeves environment.  I don't believe any of the capsules provide this feature without a separate service module.

So what?  Adding an airlock or adding a separate module, same thing.  it is a change from the baseline vehicle and not an inherent capability.  Servicing can be designed into any of the vehicles.

Anyways,
DC has a greater drawback, rendezvous and docking the rear with no direct eyes on the target.  Even with televisions cameras, the physical cues are reversed.
Jim it’s been a couple of years now, but were they not going to have a view port out back and hand held controls?
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: adrianwyard on 07/26/2015 06:01 am
Again, DC doesn't have any advantage over other vehicles for spacecraft servicing.

One of the DC variants has an arm (made by MDA).

Do you recall where the arm was to be attached?
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: yg1968 on 07/26/2015 02:19 pm
Again, DC doesn't have any advantage over other vehicles for spacecraft servicing.

One of the DC variants has an arm (made by MDA).

Do you recall where the arm was to be attached?

In the back of DC, it seems. See these images:

http://forum.nasaspaceflight.com/index.php?topic=29416.msg1152380#msg1152380

http://forum.nasaspaceflight.com/index.php?topic=29416.msg1172803#msg1172803
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: adrianwyard on 07/26/2015 05:34 pm
Thanks. Assuming this was a worked-through design (as opposed to a notional photoshop using clipart) then perhaps the arms were supposed to retract into the body of DC for return? I guess there could be room to do that, but it looks tight.

If they're not stowed somewhere we have to assume they'd either be built to survive heating during entry, or discarded each mission. Neither sounds desirable.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: jbenton on 07/26/2015 08:51 pm
Found this article: http://spacenews.com/op-ed-a-not-so-final-servicing-mission/

from the article:
Quote
In December 2014, David L. Akin of the University of Maryland’s Space Systems Laboratory presented the results of his study of maintaining Hubble using the Crew Dragon or Sierra Nevada Corp.’s Dream Chaser commercial crew spaceplane.
Quote
Akin said he did not have enough details about the other winner of NASA’s commercial crew competition, Boeing’s CST-100, to evaluate it for a Hubble maintenance mission. It is not clear that the CST-100 would be able to carry the required cargo, although that might be launched on a separate flight. Akin concluded that the loser in NASA’s commercial crew competition, Sierra Nevada’s Dream Chaser mini-shuttle, would offer some advantages over Dragon.
emphasis mine.

Most of the article is about the Hubble and Dragon. This part is pretty deep into the article. Does anyone know where to find the text or a presentation of this study?
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: TrevorMonty on 07/26/2015 10:33 pm
The DC is limited to LEO while a robotic vehicle can access both LEO and the expensive GEO satellites.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: kato on 07/27/2015 06:14 pm
LEO and GEO in-orbit servicing are entirely different business fields.

And a robotic vehicle servicing both is nothing but a fuel hog - it would be far cheaper to have separate units for LEO and GEO pretty quickly.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: A_M_Swallow on 07/27/2015 11:18 pm
LEO and GEO in-orbit servicing are entirely different business fields.

And a robotic vehicle servicing both is nothing but a fuel hog - it would be far cheaper to have separate units for LEO and GEO pretty quickly.

The separate units could be made to the same design.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: adrianwyard on 07/28/2015 12:06 am
It's the year 2020, NASA is requesting bids for 'Commercial Crew 2'.

Quote
While Boeing's CST-100 has proven reliable (with only one hard-landing injury) and remains a favorite internally, pressure is mounting to launch crew on SpaceX's Dragon vehicle due to its lower price and ability to bring unpressurized cargo on the same flights.

While some space pundits were predicting that SpaceX could be the sole winner of the CC2 contract, Boeing in a surprise move, unveiled the CST-200 as part of their CC2 bid. The CST-200 is an HL-20 derived reusable vehicle utilizing technology licensed from SNC in 2018 and Boeing's own X-37. Boeing will fly the CST-200 for the US Air Force as the 'X-37C' following the retirement of the X-37B last year.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: adrianwyard on 07/28/2015 12:36 am
Or to play out the fiction another way:

Would the fate of Dream Chaser have been different if Boeing (or Lockheed Martin) had teamed with SNC/SpaceDev to bid an HL-20 derived design for Commercial Crew?

Looking back at the contract decision, it's clear that the SNC bid was counted as risky because SNC had no history of successfully building and launching large human-rated spacecraft. (Despite their work on robotic spacecraft and aircraft).

So, if Boeing or LM had been prime, would that have been enough to make a competitive bid? I realize this is never going to be definitive, but I find it interesting to think about. I'm guessing the hybrid motors would have been deleted many years ago, but what else would have changed?
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: ChrisWilson68 on 07/28/2015 01:24 am
It's the year 2020, NASA is requesting bids for 'Commercial Crew 2'.

Quote
While Boeing's CST-100 has proven reliable (with only one hard-landing injury) and remains a favorite internally, pressure is mounting to launch crew on SpaceX's Dragon vehicle due to its lower price and ability to bring unpressurized cargo on the same flights.

While some space pundits were predicting that SpaceX could be the sole winner of the CC2 contract, Boeing in a surprise move, unveiled the CST-200 as part of their CC2 bid. The CST-200 is an HL-20 derived reusable vehicle utilizing technology licensed from SNC in 2018 and Boeing's own X-37. Boeing will fly the CST-200 for the US Air Force as the 'X-37C' following the retirement of the X-37B last year.

I don't see how that makes any sense.  For Boeing to build an HL-20 vehicle it would probably cost at least the $2 billion SNC was saying they would require.  Boeing would have to pay that $2 billion out of their per-mission income, pushing their price way up, not down, compared to CST-100.

If Boeing wanted to lower costs of CST-100 with a re-usable vehicle, the obvious way to do it would be to make CST-100 reusable, not throw it all away and start from scratch with a more complex system.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: adrianwyard on 07/28/2015 01:41 am
So the CST-100-200 comes with a reusable service module? Or if not, in what other ways does it remain competitive vs. a Dragon 2?

I suppose in my fictional account Boeing's HL-20 derived bid is perceived to be worth it to NASA despite it being more expensive than Dragon - due to dev costs you noted.

(In CC1 Boeing's higher price was justified because they offered a conservative design/program. Apparently in 2020 they get the extra $ by offering unique capabilities NASA wants.*) 

* Jim has argued there are few or none.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: ChrisWilson68 on 07/28/2015 01:47 am
So the CST-100-200 comes with a reusable service module? Or if not, in what other ways does it remain competitive vs. a Dragon 2?

I suppose in my fictional account Boeing's HL-20 derived bid is perceived to be worth it to NASA despite it being more expensive than Dragon - due to dev costs you noted.

(In CC1 Boeing's higher price was justified because they offered a conservative design/program. Apparently in 2020 they get the extra $ by offering unique capabilities NASA wants.*) 

* Jim has argued there are few or none.

I agree with Jim on this.  I haven't seen any evidence of NASA really wanting anything only Dream Chaser could provide.

If there was a need for such capabilities, NASA would have selected Dream Chaser for CCtCap.

And even farther back, if there were such a need by NASA, then Boeing, SpaceX, and/or others likely would have submitted different commercial crew bids to begin with.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: adrianwyard on 07/28/2015 01:55 am
The evidence is on your side when you consider the Commercial Crew program. But if you want to make your arguments from historical NASA interest then you have to account for the money spent on the NASA HL-20 and X-38 in the 1990s/2000s, and the STS before that.

Can we really say that all of NASA now agrees that work on HL-20, X-38 and STS was all a mistake in retrospect?
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: ChrisWilson68 on 07/28/2015 02:01 am
The evidence is on your side when you consider the Commercial Crew program. But if you want to make your arguments from historical NASA interest then you have to account for the money spent on the NASA HL-20 and X-38 in the 1990s/2000s, and the STS before that.

Can we really say that all of NASA now agrees that work on HL-20, X-38 and STS was all a mistake in retrospect?

Whether all of NASA agrees doesn't matter.  What matters is what the commercial cargo/crew program wants, and their focus is just on supplying the ISS in the near term.

Also, just because Dream Chaser isn't the right choice for commercial crew and cargo compared to particular alternatives doesn't mean those previous programs were a mistake.

Finally, when you're wondering what NASA thinks of those previous programs, consider that they were all cancelled and no follow-on program was funded for any of them.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Rocket Science on 07/28/2015 02:10 am
Gest said a couple of weeks ago that a winged vehicle that lands on a runway "would be nice to have"...
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: ChrisWilson68 on 07/28/2015 02:32 am
Gest said a couple of weeks ago that a winged vehicle that lands on a runway "would be nice to have"...

The words "nice to have" seldom equate to "I am willing to spend an extra billion dollars or two to get".

Anyway, NASA is bound by law to follow the selection criteria they laid out in the CRS-2 RFP.  I don't think "winged vehicle", "lands on runway", or "low-g cargo return" were in the list.  They gave themselves some wiggle room with something about "other factors", but if they give enough weight to "other factors" that it overrides the clear advantages in the explicit criteria the other proposals very likely have, there will be an immediate protest, and the protest will succeed.  The whole point of RFPs is to make it clear what the selection criteria are.  If there is a secret factor that wasn't listed explicitly that is important, that defeats the whole purpose of having an RFP.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: yg1968 on 07/28/2015 02:49 am
Gest said a couple of weeks ago that a winged vehicle that lands on a runway "would be nice to have"...

The words "nice to have" seldom equate to "I am willing to spend an extra billion dollars or two to get".

Anyway, NASA is bound by law to follow the selection criteria they laid out in the CRS-2 RFP.  I don't think "winged vehicle", "lands on runway", or "low-g cargo return" were in the list.  They gave themselves some wiggle room with something about "other factors", but if they give enough weight to "other factors" that it overrides the clear advantages in the explicit criteria the other proposals very likely have, there will be an immediate protest, and the protest will succeed.  The whole point of RFPs is to make it clear what the selection criteria are.  If there is a secret factor that wasn't listed explicitly that is important, that defeats the whole purpose of having an RFP.

That's exactly what NASA did for CCtCap. Cost was supposed to be the main criteria but NASA changed it to value to the government. Value to the government wasn't on the RFP but NASA still based their decision on it.  The GAO didn't have any problems with this.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: ChrisWilson68 on 07/28/2015 03:38 am
Gest said a couple of weeks ago that a winged vehicle that lands on a runway "would be nice to have"...

The words "nice to have" seldom equate to "I am willing to spend an extra billion dollars or two to get".

Anyway, NASA is bound by law to follow the selection criteria they laid out in the CRS-2 RFP.  I don't think "winged vehicle", "lands on runway", or "low-g cargo return" were in the list.  They gave themselves some wiggle room with something about "other factors", but if they give enough weight to "other factors" that it overrides the clear advantages in the explicit criteria the other proposals very likely have, there will be an immediate protest, and the protest will succeed.  The whole point of RFPs is to make it clear what the selection criteria are.  If there is a secret factor that wasn't listed explicitly that is important, that defeats the whole purpose of having an RFP.

That's exactly what NASA did for CCtCap. Cost was supposed to be the main criteria but NASA changed it to value to the government. Value to the government wasn't on the RFP but NASA still based their decision on it.  The GAO didn't have any problems with this.

I disagree.  It's not the same at all.  Cost was always supposed to be only one of several listed criteria, and CST-100 was rated higher on several of those other listed criteria.

There is no listed criterion for CRS-2 on which a cargo Dream Chaser could reasonably be expected to outperform the leading contenders.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Rocket Science on 07/28/2015 12:10 pm
Gest said a couple of weeks ago that a winged vehicle that lands on a runway "would be nice to have"...

The words "nice to have" seldom equate to "I am willing to spend an extra billion dollars or two to get".

Anyway, NASA is bound by law to follow the selection criteria they laid out in the CRS-2 RFP.  I don't think "winged vehicle", "lands on runway", or "low-g cargo return" were in the list.  They gave themselves some wiggle room with something about "other factors", but if they give enough weight to "other factors" that it overrides the clear advantages in the explicit criteria the other proposals very likely have, there will be an immediate protest, and the protest will succeed.  The whole point of RFPs is to make it clear what the selection criteria are.  If there is a secret factor that wasn't listed explicitly that is important, that defeats the whole purpose of having an RFP.
Take it up with him pal, those are his words during the ISS hearing... He's the guy who makes the choices and who then gets the money You were happy with his choice last time.... Secret selection criteria? How about doesn’t blow up..?
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: JasonAW3 on 07/28/2015 02:01 pm

     Considering the loss of the DC-X and the rejection of any shuttle like craft, I almost suspect that NASA, et al, are deliberately rejecting any sort of technologies that would lead to a completely reusable SSTO type space craft.

     No, I do NOT think that they are REALLY deliberately doing this, but itr almost seems as though everytime some promising technology that COULD lead to SSTO type craft starts developement, after a couple of setbacks, the program is immediately abandonded, and the project shelved until, "the technology is further matured".

     What bothers me is, how can a technology become further matured, when any work on that technology is abandoned?

     Essentially, unless SNC get's a contract sufficent to support further construction and developement of the Dreamchaser type craft, this will be another technology that will be abandoned, because in the case of corporations, no company is going to further develope a project that there is no immediate market for.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: ChrisWilson68 on 07/28/2015 02:13 pm
Considering the loss of the DC-X and the rejection of any shuttle like craft, I almost suspect that NASA, et al, are deliberately rejecting any sort of technologies that would lead to a completely reusable SSTO type space craft.

There's zero reason to believe, as far as I can see, that Dream Chaser would be any progress at all toward a reusable SSTO craft.

Experimental lifting-body craft have already proven that lifting bodies are feasible.  Dream Chaser's shape isn't even new, it's just a copy of an old design.  Making this into an operational craft isn't going to help with any of the things that make a reusable SSTO infeasible.

If you really want a reusable SSTO, you're much better off investing in research on materials and engine technologies.  Those are the gating factors for a practical reusable SSTO.

Even better, stop obsessing over SSTO and recognize that staging is really a wonderful technology and staging is really the way to get a practical reusable launch system.  Reusability is what matters, not SSTO.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: yg1968 on 07/28/2015 05:18 pm
Gest said a couple of weeks ago that a winged vehicle that lands on a runway "would be nice to have"...

The words "nice to have" seldom equate to "I am willing to spend an extra billion dollars or two to get".

Anyway, NASA is bound by law to follow the selection criteria they laid out in the CRS-2 RFP.  I don't think "winged vehicle", "lands on runway", or "low-g cargo return" were in the list.  They gave themselves some wiggle room with something about "other factors", but if they give enough weight to "other factors" that it overrides the clear advantages in the explicit criteria the other proposals very likely have, there will be an immediate protest, and the protest will succeed.  The whole point of RFPs is to make it clear what the selection criteria are.  If there is a secret factor that wasn't listed explicitly that is important, that defeats the whole purpose of having an RFP.

That's exactly what NASA did for CCtCap. Cost was supposed to be the main criteria but NASA changed it to value to the government. Value to the government wasn't on the RFP but NASA still based their decision on it.  The GAO didn't have any problems with this.

I disagree.  It's not the same at all.  Cost was always supposed to be only one of several listed criteria, and CST-100 was rated higher on several of those other listed criteria.

There is no listed criterion for CRS-2 on which a cargo Dream Chaser could reasonably be expected to outperform the leading contenders.

1- Perhaps. But NASA never should have tried to fudge things by saying that Boeing brings the best value to the government. That wasn't a criteria in the RFP and it gave the appearance of a bias towards Boeing.

2- As far as DC is concerned, they might be competitive on costs for CRS2. They were more competitive than Boeing for CCtCap and it will be interesting to see how competitive they are with OrbitalATK for CRS2. The selection criteria  for CRS2 are very similar to the ones for CCtCap. Cost is also supposed to be the main criteria for CRS2.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: ChrisWilson68 on 07/28/2015 05:27 pm
2- As far as DC is concerned, they might be competitive on costs for CRS2. They were more competitive than Boeing for CCtCap and it will be interesting to see how competitive they are with OrbitalATK for CRS2. The selection criteria  for CRS2 are very similar to the ones for CCtCap. Cost is also supposed to be the main criteria for CRS2.

DC in CCtCap was vastly different from DC in CRS2 because in CCtCap it was up against competitors that also needed to have their development costs paid for by the contract.  That's not the case with CRS2, which puts them at an enormous disadvantage.  Boeing, Orbital, and SpaceX all have far more modest development costs to adapt existing systems for CRS2 than SNC would have to make a cargo Dream Chaser a reality.  And it doesn't look like they could make it up by having lower recurring costs by being reusable because their CRS2 proposal has a huge non-reusable module on each flight.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: yg1968 on 07/29/2015 04:56 am
2- As far as DC is concerned, they might be competitive on costs for CRS2. They were more competitive than Boeing for CCtCap and it will be interesting to see how competitive they are with OrbitalATK for CRS2. The selection criteria  for CRS2 are very similar to the ones for CCtCap. Cost is also supposed to be the main criteria for CRS2.

DC in CCtCap was vastly different from DC in CRS2 because in CCtCap it was up against competitors that also needed to have their development costs paid for by the contract.  That's not the case with CRS2, which puts them at an enormous disadvantage.  Boeing, Orbital, and SpaceX all have far more modest development costs to adapt existing systems for CRS2 than SNC would have to make a cargo Dream Chaser a reality.  And it doesn't look like they could make it up by having lower recurring costs by being reusable because their CRS2 proposal has a huge non-reusable module on each flight.

I am not so sure about. DC has received a lot more development funding than either SpaceX or Orbital received under COTS. Certification for COTS/CRS is a lot easier than certification for commercial crew. DC would not bother entering CRS if it didn't have a bid that is somewhat competitive.  As far as reusibility, none of the cargo spacecrafts are currently being reused. So they are not at a disadvantage on this front. But I still think that the incumbents (SpaceX and Orbital ATK) hold an advantage over the others. But I am hoping that NASA will choose 3 CRS2 providers. 
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Prober on 08/17/2015 03:37 pm
There was what looked like "news" that I saw on a local tv news the other day.  Haven't been able to find it again.   All about Huntsville.

http://www.al.com/news/index.ssf/2015/06/sierra_nevada_announcement.html

Sierra Nevada Dream Chaser could make Huntsville the first commercial landing site for space craft
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: sghill on 09/10/2015 04:45 pm

Through the Dream Chaser-Preferred Landing Site Program, SNC is offering three different levels of designation, with the highest level culminating in the Federal Aviation Administration (FAA) issuing a re-entry license to SNC for the designated spaceport or airport.  This program was created based on similar work currently being done with Ellington Spaceport in Houston, Texas and the Huntsville International Airport Authority (HIA) in Huntsville, Alabama.

Huh?  What use would any of the other two lower designations be to anyone? 

I suppose one of the three levels could be launch capability, but not reentry.  And the lowest level is simply a paved runway 10,000 feet or longer.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: ChrisWilson68 on 09/11/2015 12:00 am

Through the Dream Chaser-Preferred Landing Site Program, SNC is offering three different levels of designation, with the highest level culminating in the Federal Aviation Administration (FAA) issuing a re-entry license to SNC for the designated spaceport or airport.  This program was created based on similar work currently being done with Ellington Spaceport in Houston, Texas and the Huntsville International Airport Authority (HIA) in Huntsville, Alabama.

Huh?  What use would any of the other two lower designations be to anyone? 

I suppose one of the three levels could be launch capability, but not reentry.  And the lowest level is simply a paved runway 10,000 feet or longer.

Two levels of meaningless PR.

Local politicians get to be in the news and sound like they're doing something related to space that will bring jobs to their community.  And they get to do it twice!  Meaningless Cannot-actually-re-enter Level 1 and Meaningless Cannot-actually re-enter Level 2.

Why is it that the less actual technical work a company is doing, the more PR fluff it generates?
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Rocket Science on 10/06/2015 11:05 pm
Thanks for the great article Chris. :) No "clipping of the wings" for Dream Chaser just a "folding" thus far.... ;D
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: rayleighscatter on 10/07/2015 12:26 am
I'm actually a little more convinced that DC still has a fighting chance. NASA's solicitation said they wanted to reduce the number of visiting vehicles, and with ATV done and HTV's future a bit fuzzy NASA would need to select a proposal that can carry a lot more mass/volume uphill. SNC and LM had to two proposals for big haulers and with scuttlebutt that LM may already be out of the contest it leaves SNC with the only proposal that can carry a large volume in a single flight. Even if they aren't the cheapest I think if SNC submitted a bid that's at least somewhat competitive then they genuinely may still be able to see Dream Chaser fly.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: ChrisWilson68 on 10/07/2015 02:05 am
I'm actually a little more convinced that DC still has a fighting chance. NASA's solicitation said they wanted to reduce the number of visiting vehicles, and with ATV done and HTV's future a bit fuzzy NASA would need to select a proposal that can carry a lot more mass/volume uphill. SNC and LM had to two proposals for big haulers and with scuttlebutt that LM may already be out of the contest it leaves SNC with the only proposal that can carry a large volume in a single flight. Even if they aren't the cheapest I think if SNC submitted a bid that's at least somewhat competitive then they genuinely may still be able to see Dream Chaser fly.

The enhanced Cygnus (which will be used for all later CRS-1 and presumably the CRS-2 bid) has a cargo volume of 27 cubic meters and 3,200 kg with Antares or 3,500kg with Atlas.  I can't find a volume number for Dream Chaser Cargo, but the mass limit is 5,000kg.  ISS cargoes are typically volume-limited.  If the volume scales as the mass, that's 42% to 56% more per mission.  And volume isn't changed by the launcher, so it's more likely 42%.  Is that really enough to warrant the huge development cost and development risk for Dream Chaser cargo?  It seems unlikely.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Nomadd on 10/07/2015 03:49 am


I agree with Jim on this.  I haven't seen any evidence of NASA really wanting anything only Dream Chaser could provide.

If there was a need for such capabilities, NASA would have selected Dream Chaser for CCtCap.

And even farther back, if there were such a need by NASA, then Boeing, SpaceX, and/or others likely would have submitted different commercial crew bids to begin with.

No, need wouldn't mean they'd select it. Orbital would also have to have the ability to deliver, and that was the big doubt.
 Need doesn't have to come first. Offering a unique service can generate the "need" if it's a big enough advantage.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: TrevorMonty on 10/07/2015 04:40 am
I'm actually a little more convinced that DC still has a fighting chance. NASA's solicitation said they wanted to reduce the number of visiting vehicles, and with ATV done and HTV's future a bit fuzzy NASA would need to select a proposal that can carry a lot more mass/volume uphill. SNC and LM had to two proposals for big haulers and with scuttlebutt that LM may already be out of the contest it leaves SNC with the only proposal that can carry a large volume in a single flight. Even if they aren't the cheapest I think if SNC submitted a bid that's at least somewhat competitive then they genuinely may still be able to see Dream Chaser fly.

The enhanced Cygnus (which will be used for all later CRS-1 and presumably the CRS-2 bid) has a cargo volume of 27 cubic meters and 3,200 kg with Antares or 3,500kg with Atlas.  I can't find a volume number for Dream Chaser Cargo, but the mass limit is 5,000kg.  ISS cargoes are typically volume-limited.  If the volume scales as the mass, that's 42% to 56% more per mission.  And volume isn't changed by the launcher, so it's more likely 42%.  Is that really enough to warrant the huge development cost and development risk for Dream Chaser cargo?  It seems unlikely.
DC is not that high a risk for NASA, they will not be paying for any development costs. If there are delays they can simply buy more Orbital or SpacX missions, assuming they are selected, which is likely.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: ChrisWilson68 on 10/07/2015 05:58 am
I'm actually a little more convinced that DC still has a fighting chance. NASA's solicitation said they wanted to reduce the number of visiting vehicles, and with ATV done and HTV's future a bit fuzzy NASA would need to select a proposal that can carry a lot more mass/volume uphill. SNC and LM had to two proposals for big haulers and with scuttlebutt that LM may already be out of the contest it leaves SNC with the only proposal that can carry a large volume in a single flight. Even if they aren't the cheapest I think if SNC submitted a bid that's at least somewhat competitive then they genuinely may still be able to see Dream Chaser fly.

The enhanced Cygnus (which will be used for all later CRS-1 and presumably the CRS-2 bid) has a cargo volume of 27 cubic meters and 3,200 kg with Antares or 3,500kg with Atlas.  I can't find a volume number for Dream Chaser Cargo, but the mass limit is 5,000kg.  ISS cargoes are typically volume-limited.  If the volume scales as the mass, that's 42% to 56% more per mission.  And volume isn't changed by the launcher, so it's more likely 42%.  Is that really enough to warrant the huge development cost and development risk for Dream Chaser cargo?  It seems unlikely.
DC is not that high a risk for NASA, they will not be paying for any development costs. If there are delays they can simply buy more Orbital or SpacX missions, assuming they are selected, which is likely.

I'm not sure why you say NASA won't be paying any development costs.  They won't be a separate line item, but the SNC bid has to be high enough to cover both development and operations costs while the bids of SpaceX, Boeing, and Orbital ATK won't have to cover development costs, just operations.

The risk for NASA is to schedule.  You say that if there is a delay they can switch to more Orbital or SpaceX missions, but that assumes NASA will choose three providers.  Three providers is fewer missions per provider, so less in the way of economies of scale.  Each provider has some fixed costs to cover no matter how many missions they do per year, and presumably the bids reflect that -- i.e. it costs SpaceX less per mission if they do 3 a year than if the do 1 a year, so the SpaceX bid likely passes along similar costs to NASA.

It makes more sense for NASA to stick to 2 providers, and if they are just doing two providers, it's a much bigger negative if one of them has a lot of development risk.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Rocket Science on 10/07/2015 12:37 pm
SNC is hitching its star to ULA’s 100 successful launches of Atlas V. It doesn’t matter how great one thinks their spacecraft of choice is if its launcher can’t get it to orbit without blowing up….
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: vt_hokie on 10/07/2015 04:56 pm
SNC is hitching its star to ULA’s 100 successful launches of Atlas V. It doesn’t matter how great one thinks their spacecraft of choice is if its launcher can’t get it to orbit without blowing up….

Well, I think it's more like 55 Atlas V, 45 Delta IV but nonetheless, that is true.

Edit: 30 Delta IV which leaves 15 for Delta II I suppose.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: rayleighscatter on 10/07/2015 08:28 pm
The enhanced Cygnus (which will be used for all later CRS-1 and presumably the CRS-2 bid) has a cargo volume of 27 cubic meters and 3,200 kg with Antares or 3,500kg with Atlas.  I can't find a volume number for Dream Chaser Cargo, but the mass limit is 5,000kg.  ISS cargoes are typically volume-limited.  If the volume scales as the mass, that's 42% to 56% more per mission.  And volume isn't changed by the launcher, so it's more likely 42%.  Is that really enough to warrant the huge development cost and development risk for Dream Chaser cargo?  It seems unlikely.
Mass is 5,500kg according to SNC.

Whether it's worth it or not to NASA is what we'll find out in a month. As you say it would be in the range of 50% more per mission which means for every two missions they fly they've erased the need for a third visiting vehicle. I guess we'll have to wait to see how much NASA actually weights that ability.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: ChrisWilson68 on 10/07/2015 10:30 pm
The enhanced Cygnus (which will be used for all later CRS-1 and presumably the CRS-2 bid) has a cargo volume of 27 cubic meters and 3,200 kg with Antares or 3,500kg with Atlas.  I can't find a volume number for Dream Chaser Cargo, but the mass limit is 5,000kg.  ISS cargoes are typically volume-limited.  If the volume scales as the mass, that's 42% to 56% more per mission.  And volume isn't changed by the launcher, so it's more likely 42%.  Is that really enough to warrant the huge development cost and development risk for Dream Chaser cargo?  It seems unlikely.
Mass is 5,500kg according to SNC.

Whether it's worth it or not to NASA is what we'll find out in a month. As you say it would be in the range of 50% more per mission which means for every two missions they fly they've erased the need for a third visiting vehicle. I guess we'll have to wait to see how much NASA actually weights that ability.

The 5,500kg is 5,000 pressurized and 500 unpressurized.  All these missions seem to be constrained by volume, and Cargo Dragon has 34 cubic meters of unpressured space with the extended trunk, so Cargo Dragon clearly has far, far more unpressurized cargo capacity than Cargo Dream Chaser.  That's why I didn't include the 500 unpressurized kg in the comparison -- comparing combined pressurized and unpressurized capacity leaves Cargo Dream Chaser at a clear disadvantage.  I was giving DC its best possible comparison by comparing only pressurized cargo capacities.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Rocket Science on 10/08/2015 12:42 am
SNC is hitching its star to ULA’s 100 successful launches of Atlas V. It doesn’t matter how great one thinks their spacecraft of choice is if its launcher can’t get it to orbit without blowing up….

Well, I think it's more like 55 Atlas V, 45 Delta IV but nonetheless, that is true.

Edit: 30 Delta IV which leaves 15 for Delta II I suppose.
Quite right vt, thank you the correct numbers... I have Chris's great "ULA's 100th successes" article still dancing in my head... ;D
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: a_langwich on 10/08/2015 01:40 am
The enhanced Cygnus (which will be used for all later CRS-1 and presumably the CRS-2 bid) has a cargo volume of 27 cubic meters and 3,200 kg with Antares or 3,500kg with Atlas.  I can't find a volume number for Dream Chaser Cargo, but the mass limit is 5,000kg.  ISS cargoes are typically volume-limited.  If the volume scales as the mass, that's 42% to 56% more per mission.  And volume isn't changed by the launcher, so it's more likely 42%.  Is that really enough to warrant the huge development cost and development risk for Dream Chaser cargo?  It seems unlikely.
Mass is 5,500kg according to SNC.

Whether it's worth it or not to NASA is what we'll find out in a month. As you say it would be in the range of 50% more per mission which means for every two missions they fly they've erased the need for a third visiting vehicle. I guess we'll have to wait to see how much NASA actually weights that ability.

The 5,500kg is 5,000 pressurized and 500 unpressurized.  All these missions seem to be constrained by volume, and Cargo Dragon has 34 cubic meters of unpressured space with the extended trunk, so Cargo Dragon clearly has far, far more unpressurized cargo capacity than Cargo Dream Chaser.  That's why I didn't include the 500 unpressurized kg in the comparison -- comparing combined pressurized and unpressurized capacity leaves Cargo Dream Chaser at a clear disadvantage.  I was giving DC its best possible comparison by comparing only pressurized cargo capacities.


Ah, the Dream Chaser forum.  Such optimism!  Keeps reminding me of the Dumb and Dumber line:  "so you're saying there's a chance..."

How exactly does a vehicle with wings and actuated surfaces and landing gear and thermal protection for all that complex shape and now with folding joints end up weighing less than a plain aluminum cylinder?  How else could a DC support more mass on an Atlas V than Cygnus?  Was SNC planning to use an Atlas V with more solids?  I'm pretty sure the cargo variant no longer plans to use a DEC, right?  Or, as I suspect, this is the weight the DC supports for return, but actual upmass is much less depending on the power of the LV?

Is SNC _really_ planning to finish up the atmospheric testing of DC (which would now need additional testing for the hinged control surfaces of the cargo version), and are they _really_ planning to launch a DC no matter what in 2016?  Or are they contingent on winning a CRS2 slot, in which case development can continue?  Have they ever shown a DC with complete thermal protection system in place?  What about the choice of propulsion for DC?

I guess, regarding the further development and launch test, it may make sense to tightly rein in spending until it appears there will be a market opportunity for Dream Chaser.  The challenge is what opportunities are available aren't likely to wait for x years and y more dollars of development.  I would concede, if there were a vibrant commercial space station transportation market, that a cute little winged vehicle like DC would surely seem like a sexier return ride from orbit than the ol' spam-in-a-can.

Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: ChrisWilson68 on 10/08/2015 01:48 am
How else could a DC support more mass on an Atlas V than Cygnus?

Cygnus is designed to fly on Antares, not Atlas V.  They're using Atlas V temporarily, but the limitations on the capacity of Cygnus are dictated by Antares, which has a significantly lower payload than Atlas V.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: vt_hokie on 10/08/2015 01:52 am
Direct return to a spaceflight facility via soft runway touchdown seems like a huge advantage to me vs a vehicle with either no downmass capability or one that we have to go fish out of the ocean.  So, I think there's a huge potential selling point there.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: ChrisWilson68 on 10/08/2015 02:00 am
Direct return to a spaceflight facility via soft runway touchdown seems like a huge advantage to me vs a vehicle with either no downmass capability or one that we have to go fish out of the ocean.  So, I think there's a huge potential selling point there.

SNC keeps pushing that as Dream Chaser's advantage, but I've never heard of anyone at NASA who actually needed that.

SpaceX gives priority cargo access in less than 24 hours.

Even if there are a few experiments on ISS that would benefit from it, those few benefits wouldn't be enough to justify a large price difference -- for example, the huge cost to finish Dream Chaser development.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: a_langwich on 10/08/2015 02:23 am
How else could a DC support more mass on an Atlas V than Cygnus?

Cygnus is designed to fly on Antares, not Atlas V.  They're using Atlas V temporarily, but the limitations on the capacity of Cygnus are dictated by Antares, which has a significantly lower payload than Atlas V.


But the numbers quoted are both for Atlas V flights. 

And the Antares II will not be dramatically different from Atlas V, since it will have very similar first stage capability.  There's no way Cygnus' capacity is dramatically crippled by designing for Antares II.  And I find it extremely unlikely Orbital would gimp the design of Cygnus for mass; strengthening an aluminum cylinder and a load path to the LV is trivially simple.  Furthermore, the Cygnus design is derived from a shuttle part that had much higher mass capacity, did it not?

Meanwhile, the Dream Chaser design has to be considerably heavier than Cygnus.  Even Dragon should be considerably heavier than Cygnus. 
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: RonM on 10/08/2015 02:51 am
How else could a DC support more mass on an Atlas V than Cygnus?

Cygnus is designed to fly on Antares, not Atlas V.  They're using Atlas V temporarily, but the limitations on the capacity of Cygnus are dictated by Antares, which has a significantly lower payload than Atlas V.


But the numbers quoted are both for Atlas V flights. 

And the Antares II will not be dramatically different from Atlas V, since it will have very similar first stage capability.  There's no way Cygnus' capacity is dramatically crippled by designing for Antares II.  And I find it extremely unlikely Orbital would gimp the design of Cygnus for mass; strengthening an aluminum cylinder and a load path to the LV is trivially simple.  Furthermore, the Cygnus design is derived from a shuttle part that had much higher mass capacity, did it not?

Meanwhile, the Dream Chaser design has to be considerably heavier than Cygnus.  Even Dragon should be considerably heavier than Cygnus.

The CRS-2: Dream Chaser Cargo System thread has a link to an SNC video.

http://forum.nasaspaceflight.com/index.php?topic=37049.msg1433598#msg1433598 (http://forum.nasaspaceflight.com/index.php?topic=37049.msg1433598#msg1433598)

In the video the Atlas V looks like it has five SRBs and a two engine Centaur. A maximum AV-552 configuration. The Cygnus flight will be an AV-401. That's the minimum Atlas V configuration with no SRBs and a one engine Centaur.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: ChrisWilson68 on 10/08/2015 03:32 am
How else could a DC support more mass on an Atlas V than Cygnus?

Cygnus is designed to fly on Antares, not Atlas V.  They're using Atlas V temporarily, but the limitations on the capacity of Cygnus are dictated by Antares, which has a significantly lower payload than Atlas V.


But the numbers quoted are both for Atlas V flights.

That's irrelevant, as I already pointed out.

Read what you're quoted as saying above, which is what I was responding to.  You said "How else could a DC support more mass on an Atlas V than Cygnus?".  I was giving a way that it could.

If the Cygnus was designed for a smaller launch vehicle, when they designed it they had in mind the payload dictated by that launcher.  Could they have designed it so it could handle more payload than the launch vehicle it was designed for?  Sure.  But it also might not.  Again, the constraints they were working under were dictated by Antares, not Atlas, so we shouldn't be surprised to find it caries less payload, even when flying on Atlas, because it was designed for Antares.

And the Antares II will not be dramatically different from Atlas V, since it will have very similar first stage capability.

That simplistic approach of comparing the first stages and handwaving about them being "similar" gives the wrong answer.

Fortunately, we have better information.

The payload to LEO of the smallest variant of Atlas V is 9,800 kg.  The payload of the original Antares (for which Cygnus was designed) is 6,120 kg.  That's more than the difference in capacity of Cygnus and Dream Chaser already.

Antares II is a bit more powerful, but not that much.  The official Orbital ATK fact sheet says "over 7,000 kg".   Surely it's not much over, or they would mention that.  So, there's still enough difference between Antares II and Atlas to explain the entire difference in payloads of Cygnus and Dream Chaser.  And Cygnus wasn't even designed for Antares II, it was designed for the original Antares.

https://www.orbitalatk.com/flight-systems/space-launch-vehicles/antares/docs/FS007_06_OA_3695%20Antares.pdf

But wait, there's more!  As another poster says above, Dream Chaser seems set on using a much more powerful version of Atlas V while the two Cygnus flights will use the smallest version.

There's no way Cygnus' capacity is dramatically crippled by designing for Antares II.  And I find it extremely unlikely Orbital would gimp the design of Cygnus for mass; strengthening an aluminum cylinder and a load path to the LV is trivially simple.

But that costs mass, which directly reduces the payload on the vehicle it was designed for!

Anyway, keep in mind, as I said, that CRS payloads tend to be volume, not mass, limited.  So they likely designed the volume to roughly match the mass limits for the expected density of the cargo.  Strengthening the vehicle to carry more mass makes no sense without increasing the volume.

Furthermore, the Cygnus design is derived from a shuttle part that had much higher mass capacity, did it not?

Derived-from doesn't mean identical to, and there's no reason that re-using some of the design of an earlier system means the derived system has to have the same capacity.

The Cygnus is derived from the shuttle MPLM.  But the MPLM had a width of 4.57 m and a length of 6.6 m while Cygnus has a width of 3.07 m and a length of 4.86 m.  The cargo volume of Cygnus is 18.9 cubic m while the volume of the MPLM was 31 cubic m.  Why would you think that a vehicle with a much smaller volume would be built to have the same mass capacity?

Meanwhile, the Dream Chaser design has to be considerably heavier than Cygnus.  Even Dragon should be considerably heavier than Cygnus.

So?
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Steam Chaser on 10/08/2015 04:12 am
Direct return to a spaceflight facility via soft runway touchdown seems like a huge advantage to me vs a vehicle with either no downmass capability or one that we have to go fish out of the ocean.  So, I think there's a huge potential selling point there.

SNC keeps pushing that as Dream Chaser's advantage, but I've never heard of anyone at NASA who actually needed that.

SpaceX gives priority cargo access in less than 24 hours.

Even if there are a few experiments on ISS that would benefit from it, those few benefits wouldn't be enough to justify a large price difference -- for example, the huge cost to finish Dream Chaser development.

Although it's not easy to tell how much NASA values it, the RPF includes the following optional capability:

ACCELERATED PRESSURIZED RETURN downmass
2.3.1 The contractor may provide accelerated pressurized return capability.  The requirements for this capability consist of the same required as paragraph 2.2, Pressurized Downmass, with the following modifications.  Cargo defined in subparagraph 2.2.1.2  shall be available for handover to NASA within R+6 hours in lieu of R+24 hours.

The RFP also includes the following required capability:

PRESSURIZED delivery upmass
Pressurize cargo shall be delivered ranging from 2500 to 5000 kg per flight which consists of the capabilities defined in subparagraph 2.1.1.

The DC 5000 kg figure upthread fits nicely at the top of the thread.

If I recall correctly, NASA seemed to be interested in limiting the number of flights, i.e. considerably increasing the mass/volume per cargo flight.  My impression, which I didn't verify, was that they wanted something to sort of fill the niche of the ATV.  They needed an ATV-like mass and volume, but didn't want to get it in something like 3 additional missions per year, since that would tax the schedule and astronauts at the ISS.  Thus we saw the Jupiter-Exoliner and Cargo DC proposals.  That might give Cargo DC a chance as a 3rd service provider (I am assuming that the incumbants will keep their seats at the table, given development time and risk).

The Cargo DC presumably would cost more to develop and be riskier than somewhat modified Cygnus and Dragon.  Maybe it would cost more and be riskier than a cargo Starliner, too, although that depends in part on how Boeing plays their hand.  Boeing's bid was much higher than DC for crew Starliner, but maybe Boeing will bid aggressively on cargo to protect its Starliner crew business through economies of scale.  It is possible that Sierra Nevada, recognizing that it is at a disadvantage in terms of not having a cargo or crew vehicle already in NASA's plans and paid for, is willing to eat some/all development costs to get a foot in the door on the cargo contract which could be quite large, and which might some day lead to more business like crew, cargo for commercial stations, etc.  Maybe they have a backer like Paul Allen willing to make that sort of investment.

I wouldn't assume NASA will only go for 2 cargo suppliers.  Right now they have 2, and both are out of action.  Also, both current suppliers have a specialty - large mass/volume, and payload return.  If either is out, that specialty is out, too.  Cargo DC can cover both specialties (it offers both large mass/volume and payload return), and thus can be a backup to the specialties of both Cygnus and Dragon.  Starliner seems like more of a backup to Dragon only.

Also, the reusable part of Cargo DC (the familiar part, not the expendable cargo pod) may help their bid in the long run if reusability helps them lower their long-term costs, and NASA allows used Dream Chasers to visit the ISS.

Nevertheless, if I had to bet, I'd make the following guesses for the CRS-2 result:

50% chance: Cygnus/Dragon/Starliner
30% chance: Cygnus/Dragon
20% chance: Cygnus/Dragon/Dream Chaser
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: ChrisWilson68 on 10/08/2015 04:47 am
It is possible that Sierra Nevada, recognizing that it is at a disadvantage in terms of not having a cargo or crew vehicle already in NASA's plans and paid for, is willing to eat some/all development costs to get a foot in the door on the cargo contract which could be quite large, and which might some day lead to more business like crew, cargo for commercial stations, etc.

It's too expensive for SNC.  SNC isn't a huge company.  Their bid was $2.55 billion for Crew Dream Chaser in CCtCap.  Even supposing there's profit in there, and some early operational flights, plus some crew-specific development that can be skipped, it's still a lot of money.  Plus, Crew Dream Chaser requires the disposable cargo module to be developed also.  The whole thing has to cost somewhere in the range of $1-2 billion to develop, if not more.

The revenue of all of Sierra-Nevada's businesses put together was only $1.2 billion for 2011 (the latest year I could easily find).  They surely don't have $1-2 billion lying around and nobody's going to loan it to them so they can invest in a business they won't make the money back in for the foreseeable future.

If SNC could afford to do Dream Chaser development on their own dime and were inclined to choose to do that, they wouldn't have laid off most of the Dream Chaser workforce when they lost CCtCap.

Maybe they have a backer like Paul Allen willing to make that sort of investment.

A secret investor willing to drop more than a billion dollars with no prospect of getting it back in the near future, of which we've never heard a word?  That's technically possible, but not at all likely.  For one thing, SNC has been working like crazy to convince people Dream Chaser is real and won't die.  If they had an investor, they'd trumpet that news.

I wouldn't assume NASA will only go for 2 cargo suppliers.  Right now they have 2, and both are out of action.  Also, both current suppliers have a specialty - large mass/volume, and payload return.  If either is out, that specialty is out, too.  Cargo DC can cover both specialties (it offers both large mass/volume and payload return), and thus can be a backup to the specialties of both Cygnus and Dragon.  Starliner seems like more of a backup to Dragon only.

Three suppliers instead of two means much more in fixed costs, upping the price per flight.  How much is NASA willing to pay for backups of backups?

If anything, the current situation with both SpaceX and Cygnus down shows that the worst-case scenario with two suppliers really isn't much of a problem at all.  Cygnus is showing they can launch on Atlas V if Antares is down, and the situation on the ISS is showing that NASA stockpiles enough supplies to last through some significant downtime.

Also, the reusable part of Cargo DC (the familiar part, not the expendable cargo pod) may help their bid in the long run if reusability helps them lower their long-term costs, and NASA allows used Dream Chasers to visit the ISS.

The same could be said of Dragon, but Dragon re-uses their entire pressurized vehicle while Dream Chaser Cargo throws away a significant chunk of it on every mission.  If NASA wants to lower costs with vehicle re-use, SpaceX is clearly far better than SNC.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: A_M_Swallow on 10/08/2015 11:25 am

A secret investor willing to drop more than a billion dollars with no prospect of getting it back in the near future, of which we've never heard a word?  That's technically possible, but not at all likely.  For one thing, SNC has been working like crazy to convince people Dream Chaser is real and won't die.  If they had an investor, they'd trumpet that news.


Or a second customer. Companies cannot reveal customers until they have a contract or a public "Request For ..." to reply to. The new video shows the Dream Chaser on an Ariane launch vehicle.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: redliox on 10/08/2015 11:28 am
Hopefully there's a chance they progress, although not through NASA for the immediate future.  I've read some news they're gearing up for some atmospheric testing and possibly an orbital once.  Any guesses as to how much longer they could last?
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: MarekCyzio on 10/08/2015 11:41 am
50% chance: Cygnus/Dragon/Starliner

According to The Wall Street Journal Starliner is gone. I wonder if there is any correlation between this and recent SNC announcement?
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: arachnitect on 10/08/2015 01:24 pm
50% chance: Cygnus/Dragon/Starliner

According to The Wall Street Journal Starliner is gone. I wonder if there is any correlation between this and recent SNC announcement?

They claim Lockheed's Jupiter/Exoliner is out. Have they said Starliner (CST-100) is out too?
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: jongoff on 10/08/2015 04:13 pm
Direct return to a spaceflight facility via soft runway touchdown seems like a huge advantage to me vs a vehicle with either no downmass capability or one that we have to go fish out of the ocean.  So, I think there's a huge potential selling point there.

SNC keeps pushing that as Dream Chaser's advantage, but I've never heard of anyone at NASA who actually needed that.

SpaceX gives priority cargo access in less than 24 hours.

Even if there are a few experiments on ISS that would benefit from it, those few benefits wouldn't be enough to justify a large price difference -- for example, the huge cost to finish Dream Chaser development.

Um, wrong. Rodent research (for biomedical applications) is one of the highest priority research areas on ISS today, and for some of the research they really need live return with scientist access to the rodents soon enough that the rodents don't readapt to the gravity environment. Some of those effects can kick in within minutes or hours, a day is pushing it way too far. I don't know about other examples, but there are a lot of ISS researchers who would like to have immediate post-landing access to their experiments, probably enough to justify that as a valued capability.

Whether DC is the best or only way of achieving that is debatable, but I'm pretty confident there are significant numbers of NASA researchers who would benefit strongly from much faster access than 24hrs.

~Jon
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: a_langwich on 10/08/2015 07:41 pm
How else could a DC support more mass on an Atlas V than Cygnus?

Cygnus is designed to fly on Antares, not Atlas V.  They're using Atlas V temporarily, but the limitations on the capacity of Cygnus are dictated by Antares, which has a significantly lower payload than Atlas V.


But the numbers quoted are both for Atlas V flights. 

And the Antares II will not be dramatically different from Atlas V, since it will have very similar first stage capability.  There's no way Cygnus' capacity is dramatically crippled by designing for Antares II.  And I find it extremely unlikely Orbital would gimp the design of Cygnus for mass; strengthening an aluminum cylinder and a load path to the LV is trivially simple.  Furthermore, the Cygnus design is derived from a shuttle part that had much higher mass capacity, did it not?

Meanwhile, the Dream Chaser design has to be considerably heavier than Cygnus.  Even Dragon should be considerably heavier than Cygnus.

The CRS-2: Dream Chaser Cargo System thread has a link to an SNC video.

http://forum.nasaspaceflight.com/index.php?topic=37049.msg1433598#msg1433598 (http://forum.nasaspaceflight.com/index.php?topic=37049.msg1433598#msg1433598)

In the video the Atlas V looks like it has five SRBs and a two engine Centaur. A maximum AV-552 configuration. The Cygnus flight will be an AV-401. That's the minimum Atlas V configuration with no SRBs and a one engine Centaur.

Thank you!  That makes a LOT more sense, that a much more capable Atlas is used, with a 5m fairing to handle the extra size of the winged vehicle, and more performance to handle the extra weight and size.

Of course, an AV-551 or 552 would be considerably more expensive per launch than an AV-401.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: a_langwich on 10/08/2015 08:32 pm

The payload to LEO of the smallest variant of Atlas V is 9,800 kg.  The payload of the original Antares (for which Cygnus was designed) is 6,120 kg.  That's more than the difference in capacity of Cygnus and Dream Chaser already.


I think another poster has answered the problem much more accurately above, that SNC has chosen a much more powerful variant of Atlas V.  The original question was how could SNC get more cargo capacity in addition to the larger, heavier DC structure, on an Atlas V, than Orbital could.  The answer seems to be that SNC was planning to pay tens of millions of additional dollars per launch for a much higher capacity version of Atlas V.

Dry weight of Dream Chaser:       11,300 kg. 
Dry weight of Enhanced Cygnus:    1,800 kg. 

So, at a minimum, the DC launch vehicle has to cover that difference.  The 5m fairing is another performance loss.  If they still plan to use the Dual Engine Centaur, that should be a considerable extra expense given how rarely it is flown.

It will be interesting to compare the CRS-2 numbers for the various competitors.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: a_langwich on 10/08/2015 09:11 pm
Direct return to a spaceflight facility via soft runway touchdown seems like a huge advantage to me vs a vehicle with either no downmass capability or one that we have to go fish out of the ocean.  So, I think there's a huge potential selling point there.

SNC keeps pushing that as Dream Chaser's advantage, but I've never heard of anyone at NASA who actually needed that.

SpaceX gives priority cargo access in less than 24 hours.

Even if there are a few experiments on ISS that would benefit from it, those few benefits wouldn't be enough to justify a large price difference -- for example, the huge cost to finish Dream Chaser development.

Um, wrong. Rodent research (for biomedical applications) is one of the highest priority research areas on ISS today, and for some of the research they really need live return with scientist access to the rodents soon enough that the rodents don't readapt to the gravity environment. Some of those effects can kick in within minutes or hours, a day is pushing it way too far. I don't know about other examples, but there are a lot of ISS researchers who would like to have immediate post-landing access to their experiments, probably enough to justify that as a valued capability.

Whether DC is the best or only way of achieving that is debatable, but I'm pretty confident there are significant numbers of NASA researchers who would benefit strongly from much faster access than 24hrs.

~Jon

I agree, nearly every researcher would like as close to immediate access as possible.  Not sure what marginal utility that actually provides (that is, is it worth a million extra dollars?  ten million?  probably not to most). 

I'm not so sure about the rodent example; I'm guessing such a researcher would be looking specifically at the re-adaptation process, otherwise you would probably design the experiment differently.  But Dream Chaser's more gentle reentry profile (more airplane-like, which might be useful for habituation and controls) and close access seem to be better for live animal research.

But, as your last paragraph implies, if NASA really felt that capability was valuable, both CST-100 and Dragon have a lot of room to improve access time.  Wandering off from DC, what's the dry weight of the CST-100 compared to the Vulcan thrust structure?  Boeing could demonstrate out the SMART re-use design for Vulcan by snagging CST-100 and landing it at an airfield.  :)

Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: TrevorMonty on 10/08/2015 09:33 pm
Direct return to a spaceflight facility via soft runway touchdown seems like a huge advantage to me vs a vehicle with either no downmass capability or one that we have to go fish out of the ocean.  So, I think there's a huge potential selling point there.

SNC keeps pushing that as Dream Chaser's advantage, but I've never heard of anyone at NASA who actually needed that.

SpaceX gives priority cargo access in less than 24 hours.

Even if there are a few experiments on ISS that would benefit from it, those few benefits wouldn't be enough to justify a large price difference -- for example, the huge cost to finish Dream Chaser development.

Um, wrong. Rodent research (for biomedical applications) is one of the highest priority research areas on ISS today, and for some of the research they really need live return with scientist access to the rodents soon enough that the rodents don't readapt to the gravity environment. Some of those effects can kick in within minutes or hours, a day is pushing it way too far. I don't know about other examples, but there are a lot of ISS researchers who would like to have immediate post-landing access to their experiments, probably enough to justify that as a valued capability.

Whether DC is the best or only way of achieving that is debatable, but I'm pretty confident there are significant numbers of NASA researchers who would benefit strongly from much faster access than 24hrs.

~Jon

I agree, nearly every researcher would like as close to immediate access as possible.  Not sure what marginal utility that actually provides (that is, is it worth a million extra dollars?  ten million?  probably not to most). 

I'm not so sure about the rodent example; I'm guessing such a researcher would be looking specifically at the re-adaptation process, otherwise you would probably design the experiment differently.  But Dream Chaser's more gentle reentry profile (more airplane-like, which might be useful for habituation and controls) and close access seem to be better for live animal research.

But, as your last paragraph implies, if NASA really felt that capability was valuable, both CST-100 and Dragon have a lot of room to improve access time.  Wandering off from DC, what's the dry weight of the CST-100 compared to the Vulcan thrust structure?  Boeing could demonstrate out the SMART re-use design for Vulcan by snagging CST-100 and landing it at an airfield.  :)
SMART use paraglider which should be easier to intercept/capture. Starliner uses normal parachutes.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Patchouli on 10/08/2015 09:52 pm

Um, wrong. Rodent research (for biomedical applications) is one of the highest priority research areas on ISS today, and for some of the research they really need live return with scientist access to the rodents soon enough that the rodents don't readapt to the gravity environment. Some of those effects can kick in within minutes or hours, a day is pushing it way too far. I don't know about other examples, but there are a lot of ISS researchers who would like to have immediate post-landing access to their experiments, probably enough to justify that as a valued capability.

Whether DC is the best or only way of achieving that is debatable, but I'm pretty confident there are significant numbers of NASA researchers who would benefit strongly from much faster access than 24hrs.

~Jon

They also had issues with water getting inside Dragon after splash down and shorting out the sample freezer.
Dream Chaser's landing mode would solve this.



Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: llanitedave on 10/08/2015 11:33 pm

Um, wrong. Rodent research (for biomedical applications) is one of the highest priority research areas on ISS today, and for some of the research they really need live return with scientist access to the rodents soon enough that the rodents don't readapt to the gravity environment. Some of those effects can kick in within minutes or hours, a day is pushing it way too far. I don't know about other examples, but there are a lot of ISS researchers who would like to have immediate post-landing access to their experiments, probably enough to justify that as a valued capability.

Whether DC is the best or only way of achieving that is debatable, but I'm pretty confident there are significant numbers of NASA researchers who would benefit strongly from much faster access than 24hrs.

~Jon

They also had issues with water getting inside Dragon after splash down and shorting out the sample freezer.
Dream Chaser's landing mode would solve this.


I seem to remember they corrected that issue.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: ChrisWilson68 on 10/09/2015 07:06 am

A secret investor willing to drop more than a billion dollars with no prospect of getting it back in the near future, of which we've never heard a word?  That's technically possible, but not at all likely.  For one thing, SNC has been working like crazy to convince people Dream Chaser is real and won't die.  If they had an investor, they'd trumpet that news.


Or a second customer. Companies cannot reveal customers until they have a contract or a public "Request For ..." to reply to. The new video shows the Dream Chaser on an Ariane launch vehicle.

If ESA had $2.5 billion they wanted to spend on developing a crew vehicle, they'd spend it developing Hermes or some other European-designed and built vehicle.  They would not send the money to another country.

And, if they did for some reason want to buy an American designed-and-built vehicle, they'd surely choose either Dragon or CST-100 and save the $2.5 billion in development costs.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: woods170 on 10/09/2015 08:42 am

A secret investor willing to drop more than a billion dollars with no prospect of getting it back in the near future, of which we've never heard a word?  That's technically possible, but not at all likely.  For one thing, SNC has been working like crazy to convince people Dream Chaser is real and won't die.  If they had an investor, they'd trumpet that news.


Or a second customer. Companies cannot reveal customers until they have a contract or a public "Request For ..." to reply to. The new video shows the Dream Chaser on an Ariane launch vehicle.

Don't give too much credit to the video. Dream Chaser on an Ariane V is a notional concept. Besides, this is about the version with the foldable wings for cargo. If and when SNC wants to fly a cargo Dream Chaser on Ariane V than they will have to pay for it. Arianespace is not going to give away a laucher for free. And ESA is not going to pay for it either. They don't need Dream Chaser for bartering for their ISS involvement; that's already been arranged thru ESA supplying the ESM for MPCV.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: fvandrog on 10/09/2015 09:16 am


I agree, nearly every researcher would like as close to immediate access as possible.  Not sure what marginal utility that actually provides (that is, is it worth a million extra dollars?  ten million?  probably not to most). 


Considering that the research cost on the ISS are finaced for 99%+ by the various space agencies and researchers don't get billed, I can definitely imagine scenarios where researchers consider faster access worth millions -- that is, millions of other organizations budgets.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: rayleighscatter on 10/09/2015 11:54 am

If ESA had $2.5 billion they wanted to spend on developing a crew vehicle, they'd spend it developing Hermes or some other European-designed and built vehicle.  They would not send the money to another country.

And, if they did for some reason want to buy an American designed-and-built vehicle, they'd surely choose either Dragon or CST-100 and save the $2.5 billion in development costs.
No, if ESA wanted to buy a space program Dream Chaser is the only one that makes sense. A great deal of the development is already complete. The remaining development could be done within Europe. Dream Chaser could be built by a European country. Dream Chaser could be launched on a European rocket. SNC also seems like the most willing of the three to hand over lead to a European agency and only continue working in a support capacity.

Boeing may be willing to make some concessions but they won't hand the keys to the whole program over and SpaceX isn't likely to budge on anything at all, if they don't trust the patent office they sure won't trust a foreign government.

Currently Europe's manned flight program ends with ISS in about 8 years. They have no program underway that could have any sort of maturity by the mid-2020's and with their past fascination in spaceplanes and Germany's study partnership with SNC could see a Dream Chaser adopted, with lessons from Europe's past projects like Hermes and IXV rolled in.

No, if Europe wants to continue its manned space program don't look at Dragon and CST-100, look at SLS and the Airbus A380 for the sorts of things that governments look for. Not economy, but benefits for each member. Dream Chaser as it currently exists best provides that.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: ChrisWilson68 on 10/09/2015 12:32 pm

If ESA had $2.5 billion they wanted to spend on developing a crew vehicle, they'd spend it developing Hermes or some other European-designed and built vehicle.  They would not send the money to another country.

And, if they did for some reason want to buy an American designed-and-built vehicle, they'd surely choose either Dragon or CST-100 and save the $2.5 billion in development costs.
No, if ESA wanted to buy a space program Dream Chaser is the only one that makes sense. A great deal of the development is already complete.

Not true.  It's around 10% of the $2.5 billion development cost that has already been spent.

The remaining development could be done within Europe. Dream Chaser could be built by a European country.

Then it's not Dream Chaser.  That's Europe buying up the rights to Dream Chaser and continuing it in Europe.  And it's still Europe paying SNC to buy up the rights.  Why would they do that instead of starting their own program and paying that amount to European companies?  It makes no sense.  There's nothing that SNC has done that's special -- European companies could duplicate it for about the same cost.

Again, only about 10% of the cost of the Dream Chaser program has been paid already -- not enough to make Europe buy up Dream Chaser instead of just starting from scratch if they really did want to produce their own spaceplane.

But also keep in mind that ESA has a very political budgeting system, and it all happens publicly.  If Europe were planning this, it would already be in the media.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: rayleighscatter on 10/09/2015 01:14 pm

If ESA had $2.5 billion they wanted to spend on developing a crew vehicle, they'd spend it developing Hermes or some other European-designed and built vehicle.  They would not send the money to another country.

And, if they did for some reason want to buy an American designed-and-built vehicle, they'd surely choose either Dragon or CST-100 and save the $2.5 billion in development costs.
No, if ESA wanted to buy a space program Dream Chaser is the only one that makes sense. A great deal of the development is already complete.

Not true.  It's around 10% of the $2.5 billion development cost that has already been spent.

The remaining development could be done within Europe. Dream Chaser could be built by a European country.

Then it's not Dream Chaser.  That's Europe buying up the rights to Dream Chaser and continuing it in Europe.  And it's still Europe paying SNC to buy up the rights.  Why would they do that instead of starting their own program and paying that amount to European companies?  It makes no sense.  There's nothing that SNC has done that's special -- European companies could duplicate it for about the same cost.

Again, only about 10% of the cost of the Dream Chaser program has been paid already -- not enough to make Europe buy up Dream Chaser instead of just starting from scratch if they really did want to produce their own spaceplane.

But also keep in mind that ESA has a very political budgeting system, and it all happens publicly.  If Europe were planning this, it would already be in the media.
I don't know where you keep getting this 2.5 Billion number from.

I assume you're trying to use the commercial crew bids except they also included 6 operational flights in their price.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: ChrisWilson68 on 10/09/2015 01:31 pm

If ESA had $2.5 billion they wanted to spend on developing a crew vehicle, they'd spend it developing Hermes or some other European-designed and built vehicle.  They would not send the money to another country.

And, if they did for some reason want to buy an American designed-and-built vehicle, they'd surely choose either Dragon or CST-100 and save the $2.5 billion in development costs.
No, if ESA wanted to buy a space program Dream Chaser is the only one that makes sense. A great deal of the development is already complete.

Not true.  It's around 10% of the $2.5 billion development cost that has already been spent.

The remaining development could be done within Europe. Dream Chaser could be built by a European country.

Then it's not Dream Chaser.  That's Europe buying up the rights to Dream Chaser and continuing it in Europe.  And it's still Europe paying SNC to buy up the rights.  Why would they do that instead of starting their own program and paying that amount to European companies?  It makes no sense.  There's nothing that SNC has done that's special -- European companies could duplicate it for about the same cost.

Again, only about 10% of the cost of the Dream Chaser program has been paid already -- not enough to make Europe buy up Dream Chaser instead of just starting from scratch if they really did want to produce their own spaceplane.

But also keep in mind that ESA has a very political budgeting system, and it all happens publicly.  If Europe were planning this, it would already be in the media.
I don't know where you keep getting this 2.5 Billion number from.

I assume you're trying to use the commercial crew bids except they also included 6 operational flights in their price.

And if ESA did it they wouldn't have any operational flights?
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: notsorandom on 10/09/2015 03:58 pm
If it was really important that the vehicle fly aboard a European rocket the CTS-100 is LV agnostic. It makes more sense for them to let the US government pay for the development of the CST-100 than pick up the tab for the Dream Chaser. If ESA didn't care what rocket launched from where they could contract with SpaceX or another nation. Their astronauts are already riding the Soyuz. They have been talking to China. Also with ESA contributing the Orion SM there could potentially be a ride on Orion after the current barter arrangement has concluded. They may be okay with a few BEO flights and not worry about LEO. I don't think it is realistic to think that ESA will start writing checks to save Dream Chaser. There are cheaper ways for them to get into space.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: rayleighscatter on 10/09/2015 04:21 pm

If ESA had $2.5 billion they wanted to spend on developing a crew vehicle, they'd spend it developing Hermes or some other European-designed and built vehicle.

And if ESA did it they wouldn't have any operational flights?
You were talking development, now you're talking operations. They are very different beasts.

And it still ignores the fact that so far in commercial crew nearly half a billion has been been invested in DC with how ever many million invested in the HL-20 before that. Considering it's expected that commercial crew companies have invested about 10% of what NASA gave them it means a billion dollars of lifting body research could be sold by SNC for 75 million and they would recoup their own investment and still make a profit.

If it was really important that the vehicle fly aboard a European rocket the CTS-100 is LV agnostic. It makes more sense for them to let the US government pay for the development of the CST-100 than pick up the tab for the Dream Chaser. If ESA didn't care what rocket launched from where they could contract with SpaceX or another nation. Their astronauts are already riding the Soyuz. They have been talking to China. Also with ESA contributing the Orion SM there could potentially be a ride on Orion after the current barter arrangement has concluded. They may be okay with a few BEO flights and not worry about LEO. I don't think it is realistic to think that ESA will start writing checks to save Dream Chaser. There are cheaper ways for them to get into space.
European nations hardly even buy Boeing aircraft. Convincing them to buy a Boeing spacecraft when they can buy one built by Airbus would be a trick in itself. And while they could barter for seats on Orion the cost of the SM as a part of the mission would probably only allow one European astronaut every 4 or 5 years, at best.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: jongoff on 10/09/2015 04:23 pm
It's too expensive for SNC.  SNC isn't a huge company.  Their bid was $2.55 billion for Crew Dream Chaser in CCtCap.  Even supposing there's profit in there, and some early operational flights, plus some crew-specific development that can be skipped, it's still a lot of money.  Plus, Crew Dream Chaser requires the disposable cargo module to be developed also.  The whole thing has to cost somewhere in the range of $1-2 billion to develop, if not more.

Or not. Remember the $2.55B included something like six operational flights. And CRS providers don't have anywhere near as much NASA meddling and oversight as commercial crew would. You can ditch launch escape work and associated flight demonstrations. For comparison SpaceX got the basic version of Dragon up and flying for what? About $300M? But their commercial crew bid, even after all the money they've received to-date on V2 was still another $2.6B. To me that suggests that a cargo-only Dreamchaser, even with folding wings, could be done far cheaper than you think. My guess is <$500M development cost to get to a working cargo Dream Chaser from where they're at today.

Now whether or not they could compete with whatever it is SpaceX, Boeing, and OA proposed, that remains to be seen. But I think we have far too little information to make sweeping judgements like that with any certainty.

~Jon
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: notsorandom on 10/09/2015 05:50 pm
European nations hardly even buy Boeing aircraft. Convincing them to buy a Boeing spacecraft when they can buy one built by Airbus would be a trick in itself. And while they could barter for seats on Orion the cost of the SM as a part of the mission would probably only allow one European astronaut every 4 or 5 years, at best.
Well yeah that was kinda my point. If the Europeans go the route of picking up a US vehicle it they will go with the cheapest option. If they do want to do a development program they will not go outside of the continent to find one to finish. The only way ESA will have any interest in DC is if SNC finishes it themselves.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: ChrisWilson68 on 10/09/2015 09:21 pm

If ESA had $2.5 billion they wanted to spend on developing a crew vehicle, they'd spend it developing Hermes or some other European-designed and built vehicle.

And if ESA did it they wouldn't have any operational flights?
You were talking development, now you're talking operations. They are very different beasts.

I'm talking the only number we have: $2.55 billion, which we've heard from the SNC challenge to CCtCap was the amount of their bid.  If we had it separated into development and operations, I'd use that, but we don't.

It's not at all clear whether the $2.55 billion includes 2 or 6 operational flights.  The sources don't specify that.  The NASA solicitation said that winners would get at least 2 and possibly as many as 6 orders for flights under CCtCap.  So is the $2.55 billion the minimum NASA would have had to pay if it had selected SNC (2 flights) or the maximum (6 flights)?  Based on the context, I'd guess it's the minimum (2 flights included) but that's just a guess.

And it still ignores the fact that so far in commercial crew nearly half a billion has been been invested in DC

$20 million from CCDev phase 1, $80 million from CCDev phase 2, $212.5 million from CCiCap.  That adds up to $312.5 million, which is not half a billion.

with how ever many million invested in the HL-20 before that.

Not all that was spent on HL-20 can be considered to directly benefit Dream Chaser.

SNC bought the Dream Chaser program from SpaceDev in 2008 for $38 million.  So that's a good proxy for the value of Dream Chaser at that point.  So now our total is $350.5.

Considering it's expected that commercial crew companies have invested about 10% of what NASA gave

OK, so we add 10% of $312.5 million, which is $31.25 million.  Our total is $381.75 million.

them it means a billion dollars of lifting body research

But our total, from all the things you listed, is $381.75 million invested in Dream Chaser, not $1 billion.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: JH on 10/10/2015 01:22 am
SNC can't sell DC to ESA (or any other foreign agency) as a result of export restrictions. They can sell flight services as long as the craft is owned and operated by SNC. This is according to John Roth.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: A_M_Swallow on 10/10/2015 10:58 am
SNC can't sell DC to ESA (or any other foreign agency) as a result of export restrictions. They can sell flight services as long as the craft is owned and operated by SNC. This is according to John Roth.

You hire away the (unemployed) people and tell them to design something similar.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: rayleighscatter on 10/10/2015 02:09 pm

But our total, from all the things you listed, is $381.75 million invested in Dream Chaser, not $1 billion.
That's because I never claimed 1 billion dollars invested in Dream Chaser. I could explain about quantifying past projects in their relation to ongoing development but I won't as I don't really feel like being misquoted for a third time.

SNC can't sell DC to ESA (or any other foreign agency) as a result of export restrictions. They can sell flight services as long as the craft is owned and operated by SNC. This is according to John Roth.

You hire away the (unemployed) people and tell them to design something similar.
Not to mention that perhaps uncoincidentally ESA has done a lot of research in technologies that can't be exported because of ITAR. For instance while it may be illegal to sell silica thermal tile knowledge to an entity outside the US, the ESA has come up with their own which is really quite remarkably identical.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Mike Harris-Stone on 10/10/2015 02:36 pm
The over-simplified argument -- repeated in this thread ad nauseum -- that SNC needs billions of dollars to complete DC betrays a fundamental misunderstanding of how Commercial enterprises work, and is contradicted by known facts.

How commercial enterprises work:

To undertake a business one needs initial capital (money one has or one borrows or one gets from partners) to get it started and one needs customers (people paying for the service or product) to sustain it.  If I want to open a restaurant (a business which requires a large initial investment before paying off) I can get a business loan for my capital -- if my credit and plan is good -- but then still face the challenge of attracting customers.

SNC, according to an earlier post in this thread -- has over a billion dollars of revenue --  per year.  That is money left over after paying down expenses.  That is not a small company or even a medium sized one -- that is a big company.  Furthermore, because SNC is privately held as opposed to being a corporation -- that revenue amount is not necessarily indicative of how much capital SNC possesses.  To say SNC does not have the captial to finish DC from one's armchair in Calf. is presumptuous and foolish.  SNC regularly buys other businesses.  They are starting a new business line in Colorado which involves over a billion in investment.  And SNC is investing in DC.

These are the facts.  According to a recent article in FlightGlobal.  SNC has 90 staff working full time on DC.  They have two actual vehicles -- one ETA, about to return to Armstrong for further testing -- and an ORBITAL test vehicle being jointly build by SNC and Lockheed Martin.  Listen, the owners of SNC are not stupid people.  If they've come this far, they are not overly worried about having capital to go on.

It's the second part of the equation they are working on -- Customers.  A NASA contract would be enough to secure that part.  But they don't have it yet.  However, according to SNC they do in fact have customers signed up but they have not announced them yet.

SNC is confident enough in the potential of commercial spaceflight to invest in it, even after losing Commercial Crew.  They are taking a risk, but all along they have stated that they see potential business beyond NASA for this project.

Furthermore, as a company, SNC is very financially strong because their business and their revenue stream involve multiple product lines unlike Spacex which has less.

IMHO, anyone who at all values the prospect of an expanding commercial market for space -- which would open things up tremendously -- should be cheering SNC and SpaceX and ULA and the rest on, rather than denigrating them over and over with the same lame argument.  Sure, we want to be realistic and sure there is nothing wrong with being critical.  But let's a least keep the real facts in mind.  SNC has capital.

Will DC succeed?  No one knows yet.  If they do win the the 2nd round of COTS, they are in an excellent position.  If they don't, it will be a blow but maybe not a fatal one.  Only time will tell.  It all depends on having enough customers.  Enough capital with not enough customers = a loss.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Thorny on 10/10/2015 02:37 pm
SNC can't sell DC to ESA (or any other foreign agency) as a result of export restrictions.

Is that true? We can sell F-15s, F-16s, F-18s and F-35s to other nations, but not sell Dream Chasers to Europe?
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Jim on 10/10/2015 03:09 pm

Furthermore, as a company, SNC is very financially strong because their business and their revenue stream involve multiple product lines unlike Spacex which has less.


Not really, multiple yes, but trickles and not streams.  Spacex revenue is a magnitude more.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Mike Harris-Stone on 10/10/2015 03:28 pm

Furthermore, as a company, SNC is very financially strong because their business and their revenue stream involve multiple product lines unlike Spacex which has less.


Not really, multiple yes, but trickles and not streams.  Spacex revenue is a magnitude more.

You're right....

According to the following article...Spacex's revenue...which isn't published...is estimated at 800 million a year. 

http://www.fool.com/investing/general/2014/09/21/how-much-is-spacex-stock-worth.aspx

And according to this article SNC's revenue is 176 million per year.

https://washingtontechnology.com/toplists/top-100-lists/2012/sierra-nevada.aspx

My point if one or two of SNC's streams fail, the total amount out isn't that affected, where if one or two of Spacex's rivers fail, they are very affected.

But again, you are right, that kind of annual revenue stream does give Spacex more to play with in terms of product development.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Star One on 10/10/2015 05:49 pm

SNC can't sell DC to ESA (or any other foreign agency) as a result of export restrictions.

Is that true? We can sell F-15s, F-16s, F-18s and F-35s to other nations, but not sell Dream Chasers to Europe?

F-35s can even be built outside the US with a plant in Italy, so it is a good point.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: RonM on 10/10/2015 06:16 pm

SNC can't sell DC to ESA (or any other foreign agency) as a result of export restrictions.

Is that true? We can sell F-15s, F-16s, F-18s and F-35s to other nations, but not sell Dream Chasers to Europe?

F-35s can even be built outside the US with a plant in Italy, so it is a good point.

It would take government approval. Don't see why it would be an issue when selling to the ESA.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: ChrisWilson68 on 10/10/2015 06:45 pm
But our total, from all the things you listed, is $381.75 million invested in Dream Chaser, not $1 billion.
That's because I never claimed 1 billion dollars invested in Dream Chaser.

Convenient how when you quoted me you left out the quote from you where you did, in fact, claim 1 billion dollars invested in Dream Chaser.

I could explain about quantifying past projects in their relation to ongoing development but I won't as I don't really feel like being misquoted for a third time.

I never misquoted you at all.  I quoted exactly what you said.  You made a hand-wavy argument without the exact numbers and came to a figure of $1 billion.  I plugged in the actual numbers and showed you were off by a factor of close to 3.

Now, it's time to put up or shut up.  Please, do tell us how you think "quantifying past projects in their relation to ongoing development" can dig you out of this hole.  Claiming you have an argument but you're not going to make it just makes it look like you're making up excuses.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: ChrisWilson68 on 10/10/2015 06:48 pm
SNC, according to an earlier post in this thread -- has over a billion dollars of revenue --  per year.  That is money left over after paying down expenses.

I can't really help you if you don't understand one of the most basic concepts in business: the difference between revenue and income.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Mike Harris-Stone on 10/10/2015 07:46 pm
SNC, according to an earlier post in this thread -- has over a billion dollars of revenue --  per year.  That is money left over after paying down expenses.

I can't really help you if you don't understand one of the most basic concepts in business: the difference between revenue and income.


Yep.  My bad -- I was thinking of net income.  I usually think of revenue as "sales".

However, despite my semantic mix up, it does not alter my argument:

1. SNC is a large company that is very capable of raising capital as needed.
2. SNC isn't looking for DC partners or investors.  These are useless unless they have customers.  It's no good having a vehicle if you don't have paying customers who want to utilize it.
3. SNC says they already have some customers.  Some solid, some more prospective.
4. They've invested heavily in DC.  It's not a paper program.  It has real hardware and employees.  SNC isn't stupid.  They see potential return and are willing to undertake some risk.
5. They need customers -- not joint owners willing to shoulder the cost of developing the vehicle.  The amount of risk they can undertake depends on the number of customers they can get.  NASA would seal it.   So would the DOD if they decided it was useful.   Without NASA or some other tent-pole, they may be able to go on, but the risk is higher.  Progress will be slower or it will just be cancelled.

Say what you want -- it's not as simple as they need "billions" to just finish the vehicle.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Jim on 10/10/2015 08:43 pm

1. SNC is a large company that is very capable of raising capital as needed.


Not for taking DC all the way to orbital flight with no other help
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: ChrisWilson68 on 10/10/2015 08:47 pm
SNC, according to an earlier post in this thread -- has over a billion dollars of revenue --  per year.  That is money left over after paying down expenses.

I can't really help you if you don't understand one of the most basic concepts in business: the difference between revenue and income.


Yep.  My bad -- I was thinking of net income.  I usually think of revenue as "sales".

However, despite my semantic mix up, it does not alter my argument:

1. SNC is a large company that is very capable of raising capital as needed.

It does alter your argument.  You argued that they have $1 billion a year after expenses that they can spend on investing in DC.  They do not.  What they actually have is probably more like an order of magnitude less than that.

And SNC has various investors who want to see it be profitable.  They would object to reducing profit by a large share for an unproven market.

What SNC management can actually do is very limited.  They cannot bring Dream Chaser to an operational vehicle without outside money from someone.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Mike Harris-Stone on 10/10/2015 08:56 pm

1. SNC is a large company that is very capable of raising capital as needed.


Not for taking DC all the way to orbital flight with no other help

What do you mean by "no other help?"

- If you mean paying customers, then I agree
- If you mean other investors, I don't know.  My guess is they could raise the capital if the market was solid enough.  Don't know if they have enough on their own.
- If you mean technical help, they are already working with Lockheed Martin and NASA

SNC, according to an earlier post in this thread -- has over a billion dollars of revenue --  per year.  That is money left over after paying down expenses.

I can't really help you if you don't understand one of the most basic concepts in business: the difference between revenue and income.


Yep.  My bad -- I was thinking of net income.  I usually think of revenue as "sales".

However, despite my semantic mix up, it does not alter my argument:

1. SNC is a large company that is very capable of raising capital as needed.

It does alter your argument.  You argued that they have $1 billion a year after expenses that they can spend on investing in DC.  They do not.  What they actually have is probably more like an order of magnitude less than that.

And SNC has various investors who want to see it be profitable.  They would object to reducing profit by a large share for an unproven market.

What SNC management can actually do is very limited.  They cannot bring Dream Chaser to an operational vehicle without outside money from someone.


SNC is a privately held company.  Who are these "investors?" you're talking about?

If what SNC management can do is so limited, why are they actively building an orbital test vehicle?

As to bringing DC to an operational vehicle without "outside money"  --- yes, they need a market.  They need customers.  Can they do that without NASA or the Air Force contracting them?  I don't think anyone outside the owners/management of SNC knows right now.  What customers do they already have signed up?  What would they have to do to get more?  How much of a market is there?
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Jim on 10/10/2015 08:58 pm


What do you mean by "no other help?"

- If you mean paying customers, then I agree
- If you mean other investors, I don't know.  My guess is they could raise the capital if the market was solid enough.  Don't know if they have enough on their own.
- If you mean technical help, they are already working with Lockheed Martin and NASA


They don't have the  internal funds.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Jim on 10/10/2015 09:00 pm

SNC is a privately held company.  Who are these "investors?" you're talking about


Private companies can have investors
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: JH on 10/10/2015 09:08 pm
Is that true? We can sell F-15s, F-16s, F-18s and F-35s to other nations, but not sell Dream Chasers to Europe?

Yes.

https://www.youtube.com/watch?v=pN2LlCZEmmY&index=3&list=PLwj46yNDLyTVXjKAvQbvK-GG89IMpQxPM

If the link doesn't have the proper time code for some reason, go to about 26 minutes in. He explicitly discusses the topic. He's the VP of Business Development for SNC Space Systems, so he has an intimate understanding of the topic.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Mike Harris-Stone on 10/10/2015 09:50 pm

SNC is a privately held company.  Who are these "investors?" you're talking about


Private companies can have investors

And you're saying that SNC has some of these investors?

Are you saying the owners of SNC have to consult someone else or are beholden to someone else before deciding how far they want to run with DC?

And are you saying that if SNC had enough business lined up to make DC profitable, they could never raise the capital to finish developing it and operate it because they are too small?






Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Jim on 10/10/2015 10:17 pm

And you're saying that SNC has some of these investors?

Are you saying the owners of SNC have to consult someone else or are beholden to someone else before deciding how far they want to run with DC?

And are you saying that if SNC had enough business lined up to make DC profitable, they could never raise the capital to finish developing it and operate it because they are too small?


Said nothing of the sort
But I am saying that they not going to have enough business lined up.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Mike Harris-Stone on 10/10/2015 11:43 pm

And you're saying that SNC has some of these investors?

Are you saying the owners of SNC have to consult someone else or are beholden to someone else before deciding how far they want to run with DC?

And are you saying that if SNC had enough business lined up to make DC profitable, they could never raise the capital to finish developing it and operate it because they are too small?


Said nothing of the sort
But I am saying that they not going to have enough business lined up.

Thanks for the clarification.  Outside of winning a government contract, I suspect you're right about having enough business lined up -- though I hope it ends up different.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: ChrisWilson68 on 10/10/2015 11:52 pm
SNC is a privately held company.  Who are these "investors?" you're talking about

Private companies can have investors

And you're saying that SNC has some of these investors?

Nearly all private companies of SNC's size have investors.  That's how they got to be that size.

Are you saying the owners of SNC have to consult someone else or are beholden to someone else before deciding how far they want to run with DC?

You seem to be as confused about the difference between management and ownership as you were about the difference between revenue and net income.

Except for small family businesses (think a single restaurant), nearly every company has stockholders.  In nearly every case, the management does not own a majority of the voting shares of the company.  That applies to public as well as private companies.  With private companies, there is a limited number of investors owning the shares of the company and they are not traded on a stock exchange, but they're still stockholders.

The investors are represented by the board of the company.  The board lets the management take care of running the company, but the board watches.  Boards generally take a hands-off approach as long as profits are steady.  But if the management suddenly takes a decision that will greatly reduce profits, that will get the board's attention, and they are unlikely to go along with it unless they can be convinced there's a good chance of making a lot more money in the long run.  If management loses the trust of the board, management will be replaced.

And are you saying that if SNC had enough business lined up to make DC profitable, they could never raise the capital to finish developing it and operate it because they are too small?

Nobody has ever said that.  You seem to be confused about what we're saying.  I suggest you go back and read what I and others have actually said.

Nobody has said that if the situation changes and they have a clear way to make money from Dream Chaser they couldn't get investment to complete it.  What we are saying is that in the current situation, with no evidence of customers actually willing to pay, SNC cannot finish Dream Chaser on its own funds and hope customers will show up after that.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Mike Harris-Stone on 10/11/2015 02:09 am
SNC is a privately held company.  Who are these "investors?" you're talking about

Private companies can have investors

And you're saying that SNC has some of these investors?

Nearly all private companies of SNC's size have investors.  That's how they got to be that size.

Are you saying the owners of SNC have to consult someone else or are beholden to someone else before deciding how far they want to run with DC?

You seem to be as confused about the difference between management and ownership as you were about the difference between revenue and net income.

Except for small family businesses (think a single restaurant), nearly every company has stockholders.  In nearly every case, the management does not own a majority of the voting shares of the company.  That applies to public as well as private companies.  With private companies, there is a limited number of investors owning the shares of the company and they are not traded on a stock exchange, but they're still stockholders.

The investors are represented by the board of the company.  The board lets the management take care of running the company, but the board watches.  Boards generally take a hands-off approach as long as profits are steady.  But if the management suddenly takes a decision that will greatly reduce profits, that will get the board's attention, and they are unlikely to go along with it unless they can be convinced there's a good chance of making a lot more money in the long run.  If management loses the trust of the board, management will be replaced.

And are you saying that if SNC had enough business lined up to make DC profitable, they could never raise the capital to finish developing it and operate it because they are too small?

Nobody has ever said that.  You seem to be confused about what we're saying.  I suggest you go back and read what I and others have actually said.

Nobody has said that if the situation changes and they have a clear way to make money from Dream Chaser they couldn't get investment to complete it.  What we are saying is that in the current situation, with no evidence of customers actually willing to pay, SNC cannot finish Dream Chaser on its own funds and hope customers will show up after that.


I'm not at all confused about the difference between ownership and management. 

In fact, I'm a manager at a medium size, privately held company with about 2,800 employees.  In our company, the owners are quite actively involved in running their company.  Based on what I've seen and read about SNC, I think the owners are very involved there too.  There is no way SNC would have gone this deep into developing DC and spent the $ they've spent without the owner's active support.   This notion of a conflict between management and ownership at SNC because they aren't making enough is your confusion -- not mine.  At SNC, I strongly suspect that if and when it becomes clear there is no further way ahead for DC, it will be mourned and then cancelled or mothballed as an act of mutual agreement between all parties within the company.

Also, I've read your arguments about funding over and over in this thread.  They always come down to SNC needing lots more money.

What I've tried to point out here is that it isn't capital that's the issue, i.e. money...but customers.  That's a big difference from saying they don't have the money to finish.  Saying that over and over makes them sound like idiots.

As to their being no evidence that SNC has found customers...well SNC themselves have said twice that they have customers now, but have not announced them.

It seems *maybe* we agree that the real problem is finding enough business to sustain the effort?  And maybe there isn't a market outside the government big enough for this to work on it's own.

On that, I have no argument with you nor anyone else.







Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: ChrisWilson68 on 10/11/2015 05:11 am
SNC is a privately held company.  Who are these "investors?" you're talking about

Private companies can have investors

And you're saying that SNC has some of these investors?

Nearly all private companies of SNC's size have investors.  That's how they got to be that size.

Are you saying the owners of SNC have to consult someone else or are beholden to someone else before deciding how far they want to run with DC?

You seem to be as confused about the difference between management and ownership as you were about the difference between revenue and net income.

Except for small family businesses (think a single restaurant), nearly every company has stockholders.  In nearly every case, the management does not own a majority of the voting shares of the company.  That applies to public as well as private companies.  With private companies, there is a limited number of investors owning the shares of the company and they are not traded on a stock exchange, but they're still stockholders.

The investors are represented by the board of the company.  The board lets the management take care of running the company, but the board watches.  Boards generally take a hands-off approach as long as profits are steady.  But if the management suddenly takes a decision that will greatly reduce profits, that will get the board's attention, and they are unlikely to go along with it unless they can be convinced there's a good chance of making a lot more money in the long run.  If management loses the trust of the board, management will be replaced.

And are you saying that if SNC had enough business lined up to make DC profitable, they could never raise the capital to finish developing it and operate it because they are too small?

Nobody has ever said that.  You seem to be confused about what we're saying.  I suggest you go back and read what I and others have actually said.

Nobody has said that if the situation changes and they have a clear way to make money from Dream Chaser they couldn't get investment to complete it.  What we are saying is that in the current situation, with no evidence of customers actually willing to pay, SNC cannot finish Dream Chaser on its own funds and hope customers will show up after that.


I'm not at all confused about the difference between ownership and management. 

And yet you used the word "owner" when you clearly meant management.

When I talked about SNC having to answer to investors, you replied expressing disbelieve that "owners" would have to answer to anyone.

Investors *are* the owners.  It's management that has to answer to them.

In fact, I'm a manager at a medium size, privately held company with about 2,800 employees.  In our company, the owners are quite actively involved in running their company.  Based on what I've seen and read about SNC, I think the owners are very involved there too.

What exactly have you read?  Who exactly do you think owns SNC?

There is no way SNC would have gone this deep into developing DC and spent the $ they've spent without the owner's active support.

The shareholders didn't object to it, but that's not the same as active support.  Most investors are pretty hands off.

And going along with a program when NASA is picking up 90% of the cost and they are one of three or four companies who might get a huge contract is very different from going along with it when the prospects for a NASA contract in the foreseeable future have gone and 100% of the cost has to be paid by the company.

This notion of a conflict between management and ownership at SNC because they aren't making enough is your confusion -- not mine.

There's no confusion on my part.  I never said there is a conflict between management and ownership.  I just said that in the hypothetical case that management decided to try to build Dream Chaser entirely with company money, the shareholders would likely not go along with it.

At SNC, I strongly suspect that if and when it becomes clear there is no further way ahead for DC, it will be mourned and then cancelled or mothballed as an act of mutual agreement between all parties within the company.

Also, I've read your arguments about funding over and over in this thread.  They always come down to SNC needing lots more money.

What I've tried to point out here is that it isn't capital that's the issue, i.e. money...but customers.

It is the capital that's the issue.

Having customers is one way to get the capital.

Another would be to have a billionaire willing to spend the capital even without customers, hoping they would show up later.

That's a big difference from saying they don't have the money to finish.  Saying that over and over makes them sound like idiots.

Nothing I've said makes them sound like idiots.

They saw with commercial cargo and crew opportunities at NASA a shot at making money with Dream Chaser.  So, they pursued those opportunities.  If they had won CCtCap, they would have had the money (paid by NASA) to bring Dream Chaser to operational status and make money on it.  With CRS-2, they think there's still a chance to do that, in a more limited way.

All that is rational behavior by SNC.  They lost CCtCap, but it was still a rational bet to make.  If they lose CRS-2 also and close down Dream Chaser, they still never did anything dumb, they just took a calculated risk and lost.

How is my saying they don't have the money to finish Dream Chaser themselves supposed to make anyone at SNC look like an idiot?

As to their being no evidence that SNC has found customers...well SNC themselves have said twice that they have customers now, but have not announced them.

The only think I've ever heard them say is words to the effect of "potential customers" and "opportunities to get customers".  I've never heard them say they've got real customers, in the sense of organizations making a firm commitment to pay the kind of money it would take to fund the development of Dream Chaser.

If you have a source that says otherwise -- SNC saying they have a firm commitment from customers on the scale to pay for Dream Chaser development -- please cite that source.

It seems *maybe* we agree that the real problem is finding enough business to sustain the effort?  And maybe there isn't a market outside the government big enough for this to work on it's own.

On that, I have no argument with you nor anyone else.

I'm glad we agree on that. :-)
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Rocket Science on 10/11/2015 11:33 am
Focusing on business cases is missing the entire point of Dream Chaser. It’s about Mark’s personal wish to have his lifting body fly to orbit with him on it. Saying it not realistic at the same time saying Elon colonizing Mars is going to happen with fervent belief is quite the test of logic.

Stating emphatically that Dream Chaser is unaffordable by SNC but SpaceX Can afford to go to Mars using current revenue as the case is like I said missing the point, it’s right there in the name “Dream” Chaser… Both are unaffordable at this point. Choose the dream you want to support, Mark’s modest dream of flying to LEO or Elon’s dream to die on Mars…I can support both as I admire anyone who risks it all and has the courage and drive to follow their dream….
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Mike Harris-Stone on 10/11/2015 12:34 pm
Fatih Ozmen is the primary owner of SNC.  Eren Ozmen, her husband is the other owner.  see their websites for SNC and for SNC space systems division.

You're making a kind of straw man argument here, generalizing about privately held companies and investors -- why not look into SNC itself?  I don't see what you are describing there.  Of course there are companies like the ones you describe, but I don't think SNC is one.  What we agree on is that most likely SNC is willing go a certain ways in risk (decided by the owners  - the Ozmen's since you need it spelled out)  -- after which, if it doesn't work out profitably, they will stop.  All this stuff about "investors" etc., isn't really necessary to get to that point.  The Ozmen's bought DC from SpaceDev.  They are trying to nuture it into a profitable industry.  If NASA gives them a contract, then they probably will.  If NASA doesn't, then the odds are long.

Below is one place they've discussed having potential customers lined up....

http://www.orlandosentinel.com/news/space/os-sierra-nevada-at-cape-canaveral-20150924-story.html

Quote from the article:
Quote
What's more, the company said earlier this month that it is attracting customers for a commercial space program that would not rely on NASA. Though those launches and landings could be done elsewhere — and Sierra Nevada is soliciting proposals from other sites — they also could wind up at Cape Canaveral.

John Roth, vice president of business development for Sierra Nevada's Space Systems, said the company has not released any details on its potential commercial business yet.

"What everybody is waiting on is the award of the [NASA] cargo contracts. We do have a few customers that … might still do the missions whether we get one of the cargo contracts or not," Roth said. "But a lot of customers would like to see us have that NASA contract."




Focusing on business cases is missing the entire point of Dream Chaser. It’s about Mark’s personal wish to have his lifting body fly to orbit with him on it. Saying it not realistic at the same time saying Elon colonizing Mars is going to happen with fervent belief is quite the test of logic.

Stating emphatically that Dream Chaser is unaffordable by SNC but SpaceX Can afford to go to Mars using current revenue as the case is like I said missing the point, it’s right there in the name “Dream” Chaser… Both are unaffordable at this point. Choose the dream you want to support, Mark’s modest dream of flying to LEO or Elon’s dream to die on Mars…I can support both as I admire anyone who risks it all and has the courage and drive to follow their dream….


Dream Chaser is not owned and controlled by Mark Sirangelo.  It's owned by the Osmen's -- see above.  It's definitely NOT about Mark's personal wish.  It's a business investment into an emerging market.

http://www.satellitetoday.com/launch/2015/03/31/sierra-nevada-corporation-details-future-dream-chaser-mission-concepts/







Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Rocket Science on 10/11/2015 01:32 pm
Sorry Mike, you need to dig deeper than the superficial....

~Rob
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Steam Chaser on 10/11/2015 06:43 pm
It is the capital that's the issue.

Having customers is one way to get the capital.

Another would be to have a billionaire willing to spend the capital even without customers, hoping they would show up later.

Another possible way for them to get capital is to team up with a partner.  For example, Lockheed Martin presumably has significant capital.  LM has a lot of reasons to want Dream Chaser to continue, especially now that the Jupiter/Exoliner proposal is reportedly out of the CRS-2 competition.  They would get some indirect benefit from any business ULA gets launching Dream Chaser.  They would benefit because they're heavily involved with the work of building and testing Dream Chaser at a number of facilities.  They might even be able to help their Orion program through shared work forces and facilities that would otherwise be underused (e.g.: MAF, KSC Armstrong Operations & Checkout).  I''m not sure who would be building the cargo pod, but that company could also be an investment partner.

Of course that kind of partner, or the billionaire kind, would be a lot more interested if DC wins part of the CRS-2 contract.  If you need a customer before getting this level of investment, and you need this level of investment to get the customer (i.e. to convince NASA that you can finance the development of the cargo system -- remembering what happened to RpK even after they won the NASA contract), you might have to set up an agreement where the investment is contingent on winning part of the NASA contract, and then show NASA that agreement in your CRS-2 bid.

On another note, it's interesting that the Satellite Today article mentions doing other work after the ISS cargo delivery with DC.  I wonder if the same could be done with the cargo pod.  That sort of dual use might be helpful in making the whole business case close ... although the same sort of ideas didn't seem to close it for Jupiter-Exoliner.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Todd Martin on 10/12/2015 12:35 am
I see the following reasons for hope in SNC winning part of the 2nd cargo contract:
1) Both current suppliers most recent launches ended in complete loss of mission.  This makes risk assessment much more even since DC.  If I were NASA, I wouldn't be pleased that the Govt. was stuck with most of the bill to fix Wallops because Orbital used 50 year old Russian rocket engines. 
2) SNC has offered a substantially lower bid price than Boeing with the commercial crew contract.  One could 'reasonably extrapolate SNC will be cheaper than Orbitial's Cygnus considering the premium Orbital commanded over SpaceX on COTS-1 and the fact they have to re-engine their launch vehicle.

How could SNC be price competitive when they still need to finish their spacecraft?  Well, they don't have to pay for a new launch vehicle design like Orbital and they don't have to apply all of the development costs on just the NASA contract.  They can apply other customers contract which would follow.  Note that Mark S. remarked SNC can be their own customer.  They are prime contractor & operator of satellites.  So, they could use DC to service their own satellites.

With Lockheed's proposal gone, I personally see Orbital as the weakest bidder, SpaceX as the strongest bidder.  SNC just needs to under-bid Boeing again. 
 
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: ChrisWilson68 on 10/12/2015 02:23 am
Fatih Ozmen is the primary owner of SNC.  Eren Ozmen, her husband is the other owner.  see their websites for SNC and for SNC space systems division.

I looked on their website.  I couldn't find anything saying those two are the only owners.  I didn't read every word on the site, but I did try the obvious place: I clicked on "About SNC".  Here's what it says:

Quote
SNC is a privately held company under the leadership of Chief Executive Officer Fatih Ozmen and President Eren Ozmen.

http://www.sncorp.com/AboutUs/AboutSNC

I don't see anything saying the Ozmens are the only stockholders of the company.

If you think it says that, please provide a link, and a quote of the text you think says that.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: ChrisWilson68 on 10/12/2015 02:41 am
You're making a kind of straw man argument here, generalizing about privately held companies and investors -- why not look into SNC itself?

As was the case with the word "revenue", you are misusing and seem to misunderstand the term "straw man".  A straw man argument is an argument one attributes to one's opponents in a debate but which is not really their opponents' argument.

If you think I'm making a straw man argument, you should give an example of something I claim you are saying which you are not.  But that's not what you're doing here.

Instead, you seem to think "straw man" means "incorrect".

Below is one place they've discussed having potential customers lined up....

Which makes exactly the point I was trying to make: you said SNC said they have customers lined up.  Instead, they've talked about potential customers.  The two are very different.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: a_langwich on 10/12/2015 09:02 am
I see the following reasons for hope in SNC winning part of the 2nd cargo contract:
1) Both current suppliers most recent launches ended in complete loss of mission.  This makes risk assessment much more even since DC.  If I were NASA, I wouldn't be pleased that the Govt. was stuck with most of the bill to fix Wallops because Orbital used 50 year old Russian rocket engines. 

The risk assessment angle mentioned by Gerst was as I understand it about who was likely to suffer delays in completing the design, not about launch mishap risk.  Nor does a launch mishap on a vehicle that has launched multiple times necessarily change anything about its safety relative to another.  It's just as likely to draw a royal flush in poker on the first hand as it is on the ten-thousandth hand, although with a mishap there's always the suspicion that it may not be royal flush odds, you may be looking at flush odds.  Paper rockets are always 100% safe as long as they never launch, but paper safety is meaningless compared to actual launches.

The government wasn't stuck with the repair bill for MARS because of anything NASA or Orbital did, it was stuck with it because the Virginia Senate delegation had the power to insert pork for their home state.  Even so, it paid one third the repair bill for MARS; Orbital paid another one third, and the state of Virginia paid one third.  The actual damage to NASA Wallops facilities was paid entirely by Orbital from insurance, as I understand.

NASA, Orbital, and Aerojet all looked very carefully at those 50 year old Russian rocket engines, did a fair amount of testing, and felt they understood the risks.  In fact, of those three, Orbital may have been the MOST squeamish about using the AJ-26; their lawsuit against ULA indicated they had tried to get the RD-180.


2) SNC has offered a substantially lower bid price than Boeing with the commercial crew contract.  One could 'reasonably extrapolate SNC will be cheaper than Orbitial's Cygnus considering the premium Orbital commanded over SpaceX on COTS-1 and the fact they have to re-engine their launch vehicle.

How could SNC be price competitive when they still need to finish their spacecraft?  Well, they don't have to pay for a new launch vehicle design like Orbital and they don't have to apply all of the development costs on just the NASA contract.  They can apply other customers contract which would follow.  Note that Mark S. remarked SNC can be their own customer.  They are prime contractor & operator of satellites.  So, they could use DC to service their own satellites.

True, you could make some of those assumptions. 

You could also assume that Boeing, having a capsule which was designed to be profitable with just the commercial crew contract, could offer a better deal than SNC, which still has to have development money to finish.  Or, _not_ offer a lower bid on dollars, but still be better in other bid parameters (more likely to be available at the start date, more likely to provide synergies with their crewed capsules) as they did on commercial crew.

You could assume that Orbital will have long completed and tested its engine change using existing funds under CRS-1, and only have a tank stretch to qualify for CRS-2.  Their bid was above SpaceX's, but then so was SNC's.  Orbital manufactures satellites--that was the core strength they provided for the Cygnus design--but that hasn't translated into any additional Antares business.

SNC is a satellite operator?  What constellation does it maintain?  I see that it's a prime on a test USAF microsat.  SNC being its own customer does not help it in the least--taking money out of your wallet with your left hand and placing it in your right hand hasn't improved your finances.  SNC would still need a customer paying them for whatever capability you think Dream Chaser would provide to satellites.  That hypothetical capability would have to be demonstrated, on top of DC itself.  Frankly, the economics for satellite servicing are marginal in the orbital ranges and planes Dream Chaser can reach.  Servicing's business case seems to make the most sense in GEO, where everything is nearly co-planar and opportunities are dense with low deltaV between potential targets. 


With Lockheed's proposal gone, I personally see Orbital as the weakest bidder, SpaceX as the strongest bidder.  SNC just needs to under-bid Boeing again. 
 

Is the LM proposal really gone?  Is there confirmation other than a rumor tweeted by Lurio and and an article by the less-than-attentive-to-facts Andy Pasztor?

I think I'll wait and see.  Why do you think SNC underbidding Boeing would have a different result from last time?  NASA felt CST-100 was more mature then; a year of full funding for Boeing and none for SNC will not have improved things.  And Orbital in my opinion has proven to be a great contractor, fixing mistakes on their own dime, buying launches from another company to make up a shortfall, and coming back with an even better system at an insanely fast pace.  I really like the Jupiter architecture, but of course knowing nothing about the actual bid means I don't know how realistic or competitive it was.  I could see calling up some people at USAF and seeing there are some joint programs that could be done to buy down the risk for it if it doesn't make the CRS-2 cut, because I think it is the best pure cargo architecture and one that would prove useful in many other capacities as well.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: AnalogMan on 10/12/2015 09:53 am
Fatih Ozmen is the primary owner of SNC.  Eren Ozmen, her husband is the other owner.  see their websites for SNC and for SNC space systems division.

I looked on their website.  I couldn't find anything saying those two are the only owners.  I didn't read every word on the site, but I did try the obvious place: I clicked on "About SNC".  Here's what it says:

Quote
SNC is a privately held company under the leadership of Chief Executive Officer Fatih Ozmen and President Eren Ozmen.

http://www.sncorp.com/AboutUs/AboutSNC (http://www.sncorp.com/AboutUs/AboutSNC)

I don't see anything saying the Ozmens are the only stockholders of the company.

If you think it says that, please provide a link, and a quote of the text you think says that.


http://www.sncorp.com/AboutUs/FatihOzmen (http://www.sncorp.com/AboutUs/FatihOzmen)

"Fatih Ozmen and his wife Eren Ozmen acquired the company in 1994 and set their plans in motion to expand and grow. As SNC's sole owners, they also serve as the company’s top corporate officers and provide the dynamic leadership and strategic vision that have been the driving forces behind SNC's dramatic success."
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: TrevorMonty on 10/12/2015 01:55 pm
Fatih Ozmen is the primary owner of SNC.  Eren Ozmen, her husband is the other owner.  see their websites for SNC and for SNC space systems division.

I looked on their website.  I couldn't find anything saying those two are the only owners.  I didn't read every word on the site, but I did try the obvious place: I clicked on "About SNC".  Here's what it says:

Quote
SNC is a privately held company under the leadership of Chief Executive Officer Fatih Ozmen and President Eren Ozmen.

http://www.sncorp.com/AboutUs/AboutSNC (http://www.sncorp.com/AboutUs/AboutSNC)

I don't see anything saying the Ozmens are the only stockholders of the company.

If you think it says that, please provide a link, and a quote of the text you think says that.


http://www.sncorp.com/AboutUs/FatihOzmen (http://www.sncorp.com/AboutUs/FatihOzmen)

"Fatih Ozmen and his wife Eren Ozmen acquired the company in 1994 and set their plans in motion to expand and grow. As SNC's sole owners, they also serve as the company’s top corporate officers and provide the dynamic leadership and strategic vision that have been the driving forces behind SNC's dramatic success."
I think the senior managers also have shares, probably just enough to give them a vested interest the company. In these arrangements the shares can't be held after they leave company.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Todd Martin on 10/12/2015 02:30 pm
I see the following reasons for hope in SNC winning part of the 2nd cargo contract:
1) Both current suppliers most recent launches ended in complete loss of mission.  This makes risk assessment much more even since DC.  If I were NASA, I wouldn't be pleased that the Govt. was stuck with most of the bill to fix Wallops because Orbital used 50 year old Russian rocket engines. 

The risk assessment angle mentioned by Gerst was as I understand it about who was likely to suffer delays in completing the design, not about launch mishap risk.  Nor does a launch mishap on a vehicle that has launched multiple times necessarily change anything about its safety relative to another.  It's just as likely to draw a royal flush in poker on the first hand as it is on the ten-thousandth hand, although with a mishap there's always the suspicion that it may not be royal flush odds, you may be looking at flush odds.  Paper rockets are always 100% safe as long as they never launch, but paper safety is meaningless compared to actual launches.

The government wasn't stuck with the repair bill for MARS because of anything NASA or Orbital did, it was stuck with it because the Virginia Senate delegation had the power to insert pork for their home state.  Even so, it paid one third the repair bill for MARS; Orbital paid another one third, and the state of Virginia paid one third.  The actual damage to NASA Wallops facilities was paid entirely by Orbital from insurance, as I understand.

NASA, Orbital, and Aerojet all looked very carefully at those 50 year old Russian rocket engines, did a fair amount of testing, and felt they understood the risks.  In fact, of those three, Orbital may have been the MOST squeamish about using the AJ-26; their lawsuit against ULA indicated they had tried to get the RD-180.


2) SNC has offered a substantially lower bid price than Boeing with the commercial crew contract.  One could 'reasonably extrapolate SNC will be cheaper than Orbitial's Cygnus considering the premium Orbital commanded over SpaceX on COTS-1 and the fact they have to re-engine their launch vehicle.

How could SNC be price competitive when they still need to finish their spacecraft?  Well, they don't have to pay for a new launch vehicle design like Orbital and they don't have to apply all of the development costs on just the NASA contract.  They can apply other customers contract which would follow.  Note that Mark S. remarked SNC can be their own customer.  They are prime contractor & operator of satellites.  So, they could use DC to service their own satellites.

True, you could make some of those assumptions. 

You could also assume that Boeing, having a capsule which was designed to be profitable with just the commercial crew contract, could offer a better deal than SNC, which still has to have development money to finish.  Or, _not_ offer a lower bid on dollars, but still be better in other bid parameters (more likely to be available at the start date, more likely to provide synergies with their crewed capsules) as they did on commercial crew.

You could assume that Orbital will have long completed and tested its engine change using existing funds under CRS-1, and only have a tank stretch to qualify for CRS-2.  Their bid was above SpaceX's, but then so was SNC's.  Orbital manufactures satellites--that was the core strength they provided for the Cygnus design--but that hasn't translated into any additional Antares business.

SNC is a satellite operator?  What constellation does it maintain?  I see that it's a prime on a test USAF microsat.  SNC being its own customer does not help it in the least--taking money out of your wallet with your left hand and placing it in your right hand hasn't improved your finances.  SNC would still need a customer paying them for whatever capability you think Dream Chaser would provide to satellites.  That hypothetical capability would have to be demonstrated, on top of DC itself.  Frankly, the economics for satellite servicing are marginal in the orbital ranges and planes Dream Chaser can reach.  Servicing's business case seems to make the most sense in GEO, where everything is nearly co-planar and opportunities are dense with low deltaV between potential targets. 


With Lockheed's proposal gone, I personally see Orbital as the weakest bidder, SpaceX as the strongest bidder.  SNC just needs to under-bid Boeing again. 
 

Is the LM proposal really gone?  Is there confirmation other than a rumor tweeted by Lurio and and an article by the less-than-attentive-to-facts Andy Pasztor?

I think I'll wait and see.  Why do you think SNC underbidding Boeing would have a different result from last time?  NASA felt CST-100 was more mature then; a year of full funding for Boeing and none for SNC will not have improved things.  And Orbital in my opinion has proven to be a great contractor, fixing mistakes on their own dime, buying launches from another company to make up a shortfall, and coming back with an even better system at an insanely fast pace.  I really like the Jupiter architecture, but of course knowing nothing about the actual bid means I don't know how realistic or competitive it was.  I could see calling up some people at USAF and seeing there are some joint programs that could be done to buy down the risk for it if it doesn't make the CRS-2 cut, because I think it is the best pure cargo architecture and one that would prove useful in many other capacities as well.


Note I started with the word hope.  In my opinion, the order of likely winners would be SpaceX, Boeing, SNC, Orbital, and Lockheed. 

SpaceX because they would likely be the low bidder again and their launch mishap is much easier to recover from than Orbitals.  Their Dragon spacecraft is proven. 

Boeing is 2nd.  I agree with SNC that Gerst has shown a bias towards Boeing, which means he may well put his thumb on the scale in their favor again even if NASA doesn't have the budget to afford their prices.  That doesn't mean I'm necessarily right though.  Gerst may not have the same conservative approach to a cargo contract that he displayed with crew. 

SNC is 3rd.  I do believe SNC will be aggressive in their pricing; everything Mark S. has said and done has reinforced my belief they REALLY want DC to be successful.  Boeing wants Boeing prices regardless of costs.  An SNC contract would broaden NASA's options of spacecraft to choose from and provide better cargo return capability.

Orbital is 4th.  I rank Orbital behind SNC because I believe their bid will be substantially higher, their launch vehicle needs a complete re-design which does affect cost, schedule & flight risk.  Then, there's the fact that their spacecraft is the only one which cannot return any cargo.  I would disagree with you regarding the mishap over Wallops.  Orbital made the choice to select those engines for their rocket.  That poor judgement put a lot people and property at risk.  They got lucky no one was killed.  NASA has every obligation to keep that in mind when making a follow-up contract. 

Lockheed is 5th.  When 2 sources say they are out of the competition, they probably are.  I agree that is a shame since they had the most useful design to do other things.



   
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Rocket Science on 11/22/2015 01:29 am
Nice larger pic of DC from SNC that I posted in the update thread.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: yg1968 on 11/22/2015 02:02 am
Orbital DC is in the background.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: yg1968 on 11/22/2015 02:06 am
Orbital Dream Chaser!!

SNC:

Lockheed Martin recently completed our Dream Chaser® orbital cabin assembly!

I wonder if they could use that cabin assemby for cargo DC.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Rocket Science on 11/22/2015 11:15 am
Some interesting bits of construction info from Composites World.

"Lockheed Martin recently completed the Dream Chaser orbital cabin assembly, marking a significant milestone in the construction of this vehicle.  This assembly is the largest high-temperature unitized structure ever fabricated at U.S. Air Force Plant 4. The assembly utilized three-dimensional woven joints, to integrate internal frames with external carbon skins in a single co-bond operation, meaning nearly all fasteners on this critical cabin assembly are eliminated.

“Upon completion, the Dream Chaser orbital vehicle will be the most advanced composite structure ever built. We look forward to Dream Chaser becoming the world leader in this area and to its first orbital flight,” Sirangelo said."

http://www.compositesworld.com/news/dream-chaser-preparing-for-second-flight-test
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: docmordrid on 01/11/2016 05:59 pm
And from SNC themselves:

https://twitter.com/SNCspacesystems/status/686618479277899777 (https://twitter.com/SNCspacesystems/status/686618479277899777)[/size]
Quote
Lots of chatter stemming from the article noting #SNCDreamChaser launch in 2016. @NASA #CRS2 award will set dates and more. Stay tuned!

That sounds pretty upbeat. Sounds like a hint they got an award.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: yg1968 on 01/11/2016 06:15 pm
And from SNC themselves:

https://twitter.com/SNCspacesystems/status/686618479277899777 (https://twitter.com/SNCspacesystems/status/686618479277899777)[/size]
Quote
Lots of chatter stemming from the article noting #SNCDreamChaser launch in 2016. @NASA #CRS2 award will set dates and more. Stay tuned!

That sounds pretty upbeat. Sounds like a hint they got an award.

They likely don't know. They usually find out a day before or on the day of the awards.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: ChrisWilson68 on 01/11/2016 06:16 pm
And from SNC themselves:

https://twitter.com/SNCspacesystems/status/686618479277899777 (https://twitter.com/SNCspacesystems/status/686618479277899777)[/size]
Quote
Lots of chatter stemming from the article noting #SNCDreamChaser launch in 2016. @NASA #CRS2 award will set dates and more. Stay tuned!

That sounds pretty upbeat. Sounds like a hint they got an award.

Really?  To me it sounds like they're trying to back away from any sort of commitment to a launch in 2016 without explicitly saying that, and trying to say that the launch schedule is uncertain because it depends on whether they got a CRS2 award, which is unknown.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: baldusi on 01/11/2016 07:58 pm
It was all about ULA's CEO confusing the Starliner first flight with DreamChaser's.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Star One on 01/11/2016 09:44 pm
And from SNC themselves:

https://twitter.com/SNCspacesystems/status/686618479277899777 (https://twitter.com/SNCspacesystems/status/686618479277899777)[/size]
Quote
Lots of chatter stemming from the article noting #SNCDreamChaser launch in 2016. @NASA #CRS2 award will set dates and more. Stay tuned!

That sounds pretty upbeat. Sounds like a hint they got an award.

Really?  To me it sounds like they're trying to back away from any sort of commitment to a launch in 2016 without explicitly saying that, and trying to say that the launch schedule is uncertain because it depends on whether they got a CRS2 award, which is unknown.

Not sure if I would read such a pessimistic interpretation into it.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: BrianNH on 01/14/2016 06:07 pm
Bumping to remind people that we have a DISCUSSION thread.  Let's keep the UPDATE thread for updates.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: abaddon on 01/14/2016 06:33 pm
Also, seems like Dream Chaser thread should probably be in Commercial Space Flight General rather than Commercial Crew at this point.

I disagree. DC is still part of commercial crew program through its CCiCap contract. There is funded and unfunded milestones in that extended agreement. The NASA Commercial Crew Program always insists that it is sill working with both SNC and Blue (through unfunded CCDev 2 milestones in Blue's case).
Yeah... maybe.  There is logic to that.  Of course Boeing is no longer in this section (having its own sub-forum), Dragon V2 doesn't have a section but is spread nilly-willy throughout the SpaceX forum, CRS-2 is in Commercial Space despite the DC thread being here... so it's all a bit scattered right now.

If DreamChaser were to win a CRS2 contract, I think it would be better with the other CRS2 discussions, presumably not in this section.

Replied in Discussion thread as I should have in the first place; sorry about that.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: yg1968 on 01/14/2016 07:06 pm
If DC wins, I suspect that it will get its own sub-forum.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: BrightLight on 01/14/2016 07:08 pm
If DC wins, I suspect that it will get its own sub-forum.
If DC wins, I'm drinking single malt tonight.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: JasonAW3 on 01/14/2016 07:28 pm
If DC wins, I suspect that it will get its own sub-forum.
If DC wins, I'm drinking single malt tonight.

That'll make two of us.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: wjbarnett on 01/14/2016 08:13 pm
Way to go SNC! Congrats!!
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: rayleighscatter on 01/14/2016 08:19 pm
Genuinely excited about this. Way to go SNC!
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: TrevorMonty on 01/14/2016 08:24 pm
Congratulations SNC.

Boeing and LM are still partial winners,  as they still get to profit from ULA launching DC.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Endeavour_01 on 01/14/2016 08:32 pm
Congratulations to SNC. I can't wait to see Dream Chaser soar. Winged spacecraft are back baby!  :D :D :D :D
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: kevinof on 01/14/2016 08:32 pm
Time to break out that single malt (Hope it's an Irish one and none of that Scotch stuff).

Great for DC - Liked the ideas of a mini winged craft and at least the U.S. will get a variety of vehicles going into the future.

Great stuff.

If DC wins, I suspect that it will get its own sub-forum.
If DC wins, I'm drinking single malt tonight.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: QuantumG on 01/14/2016 08:41 pm
Anyone know how many dollars yet?
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: arachnitect on 01/14/2016 08:45 pm
Anyone know how many dollars yet?


NASA is pretending they don't know.

($$$).
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Alpha Control on 01/14/2016 08:49 pm
Time to break out that single malt (Hope it's an Irish one and none of that Scotch stuff).

Great for DC - Liked the ideas of a mini winged craft and at least the U.S. will get a variety of vehicles going into the future.

Great stuff.

If DC wins, I suspect that it will get its own sub-forum.
If DC wins, I'm drinking single malt tonight.

Great news! So excited for SNC, and for Dream Chaser. As Endeavour_01 said above, winged spacecraft are back!  The baby orbiter will spread her wings and fly!

ETA  ALT (Approach & Landing Test) Flight 2 up next. That will garner a lot interest on this site and elsewhere, I'm sure.

I'll join you all in raising a glass tonight.  Cheers!
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Bubbinski on 01/14/2016 08:52 pm
Sweet news, good to see a new winged spacecraft. Hoping this will help position SNC to successfully enter a crewed DreamChaser in the next NASA ISS commercial crew competition or for other crewed roles (orbital tourism?).
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: IanO on 01/14/2016 08:53 pm
Does this award mean that the first DreamChaser test flight is likely to move forward back into 2017 and get a firm date?
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: BrightLight on 01/14/2016 08:55 pm
Some images of the DC show the DC attached to the "cargo pod" docked to the ISS, my question is: without the "cargo pod" is the back end of the DC fitted with a CBM hatch? or will docking be with one version of DC and berthing another?
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Lars-J on 01/14/2016 09:05 pm
Some images of the DC show the DC attached to the "cargo pod" docked to the ISS, my question is: without the "cargo pod" is the back end of the DC fitted with a CBM hatch? or will docking be with one version of DC and berthing another?

It sounds like there will be two "cargo pod" variants... One that has a CBM hatch, and a different one with a regular docking hatch. (but I could be wrong)
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Lars-J on 01/14/2016 09:09 pm
And congrats to DC!  8)
I'm not much of a fan of winged spacecraft in general, but having three very different kind of vehicles is a great flexibility.

And this way DC can have a chance to prove their doubters wrong. (or right) ;)
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Dante80 on 01/14/2016 09:15 pm
Congrats to SNC and HOLY MACARONI the DC will FLY!!
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: abaddon on 01/14/2016 09:19 pm
Anyone know how many dollars yet?
Yeah, that.  They will announce later.

I'm cautiously pleased about this, as long as they're not spending too much bankrolling DC development as compared to the other vehicles.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: BrightLight on 01/14/2016 09:29 pm
The cargo pod can have either a LIDS or CBM - making it a very flexible system for the ISS, especially for LON.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Rocket Science on 01/14/2016 09:38 pm
Like I said a couple of years back to quote Spock  "I've been dead before"... Welcome back to life Dream Chaser! :)
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: BrightLight on 01/14/2016 09:46 pm
Like I said a couple of years back to quote Spock  "I've been dead before"... Welcome back to life Dream Chaser! :)
I think the dream chaser was born in the 1964 worlds fair and its like the clock stopped (for me at least) and now the clock is ticking again - new spacecraft, new LV's - its a whole new world :)
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Lars-J on 01/14/2016 09:54 pm
Is the Cargo DC for CRS2 a full-size DC, or a slightly scaled down version? Do we know for sure?
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Rocket Science on 01/14/2016 09:56 pm
I feel its time for "the song"... ;D

https://www.youtube.com/watch?v=-8OpsPok6iQ
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Darkseraph on 01/14/2016 09:57 pm
Will this entail NASA paying additional money for the development of Cargo Dream Chaser or are these contracts just for missions?
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Lars-J on 01/14/2016 09:58 pm
A new DC image from today's Sierra Nevada press release, showing it berthed:

http://spaceref.com/news/viewpr.html?utm_medium=srs.gs-twitter&utm_content=api&pid=47688&utm_campaign=&utm_source=t.co
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: rayleighscatter on 01/14/2016 10:02 pm
A little image dump from SNC, all renderings. Plus a PDF infographic.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Rocket Science on 01/14/2016 10:05 pm
Is the Cargo DC for CRS2 a full-size DC, or a slightly scaled down version? Do we know for sure?
That would be a great question for Chris to ask Mark at SNC Lar...(hint, hint) ;)
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: a_langwich on 01/14/2016 10:23 pm
Is the Cargo DC for CRS2 a full-size DC, or a slightly scaled down version? Do we know for sure?
That would be a great question for Chris to ask Mark at SNC Lar...(hint, hint) ;)

The CRS-2 bid involved folding wings, to be encapsulated in a 5m fairing, but no indication of other size changes.  I guess that was well known.

How they handle the weight of the folding wings, and heat shielding at the joint, will be interesting.  Actually, the entire heat shield system will be very interesting, in the complex shape and actuated flight surfaces, the weight, how it's refurbished, how it handles operationally.

Did the hybrid rocket engines go away?  The cargo variant doesn't need launch escape thrust levels, so perhaps DC-cargo just has the tiny manuevering thrusters.

I guess it's time to re-hire some of those DC employees again.  Woohoo for them!

I wonder how many flight DCs they plan to make?  Two?  More?
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Star One on 01/14/2016 10:39 pm
It makes it look like, now that ATV has gone, the biggest of the cargo carriers to dock to ISS, or is it still smaller than the HTV?
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Danderman on 01/14/2016 10:46 pm
Wait a minute, the cargo module is thrown away before re-entry?

So, does that mean that there is no downmass capability, or is there some way to move from the cargo module into DC itself?

Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: QuantumG on 01/14/2016 10:47 pm
It means that pressurized cargo can go up in the DC or the cargo module, but only down in the DC.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Rocket Science on 01/14/2016 10:48 pm
Wait a minute, the cargo module is thrown away before re-entry?

So, does that mean that there is no downmass capability, or is there some way to move from the cargo module into DC itself?
It carries internal cargo as well. The module allows external cargo up and trash down upon release and burn up on entry. (Look at Lar's pic one page back)
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: dwheeler on 01/14/2016 10:52 pm
I'm digging the new dark super villain look. Has something changed in the TPS requirements?
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: rayleighscatter on 01/14/2016 11:05 pm
Is the Cargo DC for CRS2 a full-size DC, or a slightly scaled down version? Do we know for sure?
One of SNC's graphics says Cargo DC is 30 feet long, and some previous DC materials cite crewed DC as being 29.5 feet long so I'd say it looks to be the same size. I'd assume the extra half foot just comes from rounding numbers for brevity.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Rocket Science on 01/14/2016 11:07 pm
I'm digging the new dark super villain look. Has something changed in the TPS requirements?
Nah, just a wrap... ;D
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: catdlr on 01/15/2016 12:54 am
SNC's Dream Chaser® Cargo System A Transportation System to Deliver Cargo to the ISS for NASA

Published on Jan 14, 2016
Sierra Nevada Corporation's Dream Chaser spacecraft has been selected under the second phase of NASA's Commercial Resupply Services contract to ferry cargo, crew supplies and experiments to the International Space Station. (Video courtesy of Sierra Nevada Corporation).

https://youtu.be/0mIlGw--e60
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: yg1968 on 01/15/2016 01:28 am
Did the hybrid rocket engines go away?  The cargo variant doesn't need launch escape thrust levels, so perhaps DC-cargo just has the tiny manuevering thrusters.

Yes, they dumped the hybrids.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: QuantumG on 01/15/2016 01:31 am
Even the crew version isn't expected to have hybrids, since the acquisition of ORBITEC and their vortex rockets.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Nibb31 on 01/15/2016 01:40 am
The video mentions reboost capability. How does it do that ?
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Rocket Science on 01/15/2016 01:46 am
The video mentions reboost capability. How does it do that ?
Forward RCS...
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Prettz on 01/15/2016 01:54 am
How they handle the weight of the folding wings, and heat shielding at the joint, will be interesting.  Actually, the entire heat shield system will be very interesting, in the complex shape and actuated flight surfaces, the weight, how it's refurbished, how it handles operationally.
Surely it's less than the weight lost by completely omitting the two engine pods?
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Lee Jay on 01/15/2016 01:55 am
SNC's Dream Chaser® Cargo System A Transportation System to Deliver Cargo to the ISS for NASA

Published on Jan 14, 2016
Sierra Nevada Corporation's Dream Chaser spacecraft has been selected under the second phase of NASA's Commercial Resupply Services contract to ferry cargo, crew supplies and experiments to the International Space Station. (Video courtesy of Sierra Nevada Corporation).

https://youtu.be/0mIlGw--e60

Does this video show an Atlas V 542?
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: RonM on 01/15/2016 02:00 am
Does this video show an Atlas V 542?

It might even be an Atlas V 552.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Lee Jay on 01/15/2016 02:02 am
Does this video show an Atlas V 542?

It might even be an Atlas V 552.

Yeah...hard to tell.  But what is it with them and the dual-engine Centaur?  The original choice was 402.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: yg1968 on 01/15/2016 02:04 am
The cargo version requires more solid boosters.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Steven Pietrobon on 01/15/2016 03:15 am
Here's the SNC press release. No mention of the award amount.

SPARKS, Nev. (January 14, 2016) – Today, NASA competitively selected Sierra Nevada Corporation’s (SNC) Space Systems to receive a multi-year contract to provide cargo delivery, return and disposal services for the International Space Station (ISS). SNC received a Commercial Resupply Services 2 (CRS2) contract, to fulfill a minimum of six cargo delivery service missions to and from the ISS utilizing SNC’s Dream Chaser Cargo System. NASA’s selection of SNC for the CRS2 program will enable spacecraft reusability and runway landings for United States’ cargo delivery and access to the ISS through 2024.

“SNC is honored to be selected by NASA for this critical U.S. program,” said Eren Ozmen, president of Sierra Nevada Corporation. “In such a major competition, we are truly humbled by the show of confidence in SNC and look forward to successfully demonstrating the extensive capabilities of the Dream Chaser spacecraft to the world. SNC’s receipt of this award is an American Dream come true for all of us. We thank NASA, the Administration and Congress for recognizing the importance of this vital program by supporting the CRS2 contract.” 

SNC is the owner and prime operator of the reusable Dream Chaser spacecraft, which has been in development for over 10 years, including six years as part of NASA’s Commercial Crew Program and leverages over 40 years of NASA development and space shuttle heritage.

“The Dream Chaser Cargo System offers NASA a safe, reliable and affordable solution for ISS cargo delivery, return and disposal, ensuring the effective utilization and sustainability of the ISS for years to come,” said Mark N. Sirangelo, corporate vice president of SNC’s Space Systems. “Within a few short years, the world will once again see a United States winged vehicle launch and return from space to a runway landing.  We wanted to thank our more than 30 industry, university, international and NASA center partners for helping us make history and open up the next generation of spaceflight.”

SNC’s Dream Chaser Cargo System features include:

    An innovative folding-wing design which allows the Dream Chaser spacecraft to fit inside existing launch vehicle fairings, making it compatible with a diverse suite of rockets and assuring access to space
    The ability to simultaneously deliver 5,500 kg of pressurized and unpressurized cargo to the ISS, which exceeds NASA’s CRS2 RFP requirements
    High reusability that reduces costs and enables quick reflight. Responsive pressurized cargo return capability – ensuring scientific experiments are promptly returned to the researchers as intended and without contamination
    Low-g reentry and gentle runway landing – critical for the return of sensitive payloads, scientific experiments and immediate access to cargo
    All non-toxic propellants and consumables, making the Dream Chaser spacecraft the first vehicle in history to achieve this level of environmental responsibility

The Dream Chaser program will continue to be based in Louisville, Colorado. SNC expects to significantly expand operations in Colorado and throughout the United States, in conjunction with its international partners, to support contract requirements. The growing employment scope and economic impact of SNC and its partner organizations – the Dream Team – now spans over 25 states and 15 countries and will continue to grow under the CRS2 contract.

More information about SNC’s Dream Chaser program can be found at www.SNCspace.com.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: a_langwich on 01/15/2016 03:28 am
The cargo version requires more solid boosters.

Because the CRS-2 proposal had to support 2.5 - 5 metric tons cargo in addition to the vehicle. 

I'm curious how SNC managed to keep their bid competitive, when an Atlas V 552 has to run ~3-4x the price of a Falcon 9. 
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Lars-J on 01/15/2016 05:38 am

The cargo version requires more solid boosters.

I guess the cargo pod adds mass - but still, an Atlas V 552?!? (If video is accurate) Holy mass growth, Batman!

That won't be cheap. Atlas V doesn't get any more expensive than that.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Lars-J on 01/15/2016 05:46 am

The cargo version requires more solid boosters.

Because the CRS-2 proposal had to support 2.5 - 5 metric tons cargo in addition to the vehicle.

But DC should have no problem carrying 2.5 metric tons inside, even without the cargo pod. I would think.

I'm curious how SNC managed to keep their bid competitive, when an Atlas V 552 has to run ~3-4x the price of a Falcon 9.

Curious indeed. NASA must *really* like DC, they might have been a shoe-in for commercial crew if not for the hybrid propulsion.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: jongoff on 01/15/2016 05:54 am

The cargo version requires more solid boosters.

Because the CRS-2 proposal had to support 2.5 - 5 metric tons cargo in addition to the vehicle.

But DC should have no problem carrying 2.5 metric tons inside, even without the cargo pod. I would think.

I'm curious how SNC managed to keep their bid competitive, when an Atlas V 552 has to run ~3-4x the price of a Falcon 9.

Curious indeed. NASA must *really* like DC, they might have been a shoe-in for commercial crew if not for the hybrid propulsion.

Note that the Cargo Dreamchaser carries 5500kg, not 2500kg of cargo, so actually above what NASA requested. And really do any of know how much a commercially procured Atlas V costs? Orbital doesn't seem to be complaining. If we saw the actual prices maybe DC would be more competitive than you're giving them credit for.

Note, I'm not a huge fan of wings/lifting bodies, but I think a lot of people are assuming they know more about SNC's cost structure than any of us likely do.

~Jon
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Lampyridae on 01/15/2016 05:55 am

The cargo version requires more solid boosters.

Because the CRS-2 proposal had to support 2.5 - 5 metric tons cargo in addition to the vehicle.

But DC should have no problem carrying 2.5 metric tons inside, even without the cargo pod. I would think.

I'm curious how SNC managed to keep their bid competitive, when an Atlas V 552 has to run ~3-4x the price of a Falcon 9.

Curious indeed. NASA must *really* like DC, they might have been a shoe-in for commercial crew if not for the hybrid propulsion.

Well, even with 2 different service providers, there were still failures within months of one another, and even a good ol' reliable Progress was lost. Plus, part of the aim of commercial resupply is to foster American launch services. One of these companies might just go belly-up, after all.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Lampyridae on 01/15/2016 06:02 am
A new DC image from today's Sierra Nevada press release, showing it berthed:

http://spaceref.com/news/viewpr.html?utm_medium=srs.gs-twitter&utm_content=api&pid=47688&utm_campaign=&utm_source=t.co

Dang but that thing looks way cool with the new colours (tiles? paint?). Hopefully they will make a manned version and call it the Farscape. It also has a little of that Imperial Shuttle cool with the canted solar panels. Fit to cart Vader around.

What frustrates me is that the USA are steadily gaining a wide range of LEO capabilities and... no payloads for SLS. Crewed flight only on #3. Maybe in 2024. Maybe. If Soyuz taxi rides were embarrassing, this is going to be a major interest killer.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: TrevorMonty on 01/15/2016 06:06 am

The cargo version requires more solid boosters.

I guess the cargo pod adds mass - but still, an Atlas V 552?!? (If video is accurate) Holy mass growth, Batman!

That won't be cheap. Atlas V doesn't get any more expensive than that.
ULA are targetting $100-110 for V401 so V552 should be well under $200m, while delivering 5500kg. By 2019 the Vulcan should be flying with 2-3 less SRBs required, none once ACES is introduced (2022-23).

NASA really liked low G reentry and quick access to returned experiments. This is actually critical for some experiments.


Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Lars-J on 01/15/2016 06:09 am
Note that the Cargo Dreamchaser carries 5500kg, not 2500kg of cargo, so actually above what NASA requested. And really do any of know how much a commercially procured Atlas V costs? Orbital doesn't seem to be complaining. If we saw the actual prices maybe DC would be more competitive than you're giving them credit for.

Note, I'm not a huge fan of wings/lifting bodies, but I think a lot of people are assuming they know more about SNC's cost structure than any of us likely do.

~Jon

Jon, I think we are more concerned/inquisitive about ULAs cost structure, not SNCs. If ULA are selling AV 552 launches at competitive enough rates that SNC can cost competitive with the CRS1 providers, ULA has been overcharging the DoD far more than most of us suspect.

Some cost transparency for these three contracts would be very welcome.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Star One on 01/15/2016 06:25 am

Note that the Cargo Dreamchaser carries 5500kg, not 2500kg of cargo, so actually above what NASA requested. And really do any of know how much a commercially procured Atlas V costs? Orbital doesn't seem to be complaining. If we saw the actual prices maybe DC would be more competitive than you're giving them credit for.

Note, I'm not a huge fan of wings/lifting bodies, but I think a lot of people are assuming they know more about SNC's cost structure than any of us likely do.

~Jon

Jon, I think we are more concerned/inquisitive about ULAs cost structure, not SNCs. If ULA are selling AV 552 launches at competitive enough rates that SNC can cost competitive with the CRS1 providers, ULA has been overcharging the DoD far more than most of us suspect.

Some cost transparency for these three contracts would be very welcome.

Yes but the ULA have been doing a lot of restructuring in recent years to aggressively drive their costs down since they have started to come under stronger competitive pressure.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Dante80 on 01/15/2016 07:57 am
A question. What is the (numerical) difference in re-entry mission g loads between the DCcargo and a capsule like Starliner and Dragon?

Btw...an Atlas V 552 is indeed the most expensive variant you can get for a somewhat expensive LV. Contracting 6 of them though in a single deal should bring the per unit cost down considerably. I think that LM (the ones that will sell them) would be happy to oblige.

Moreover, SNC probably has to make a couple of Dreamchasers for the contract at hand, they don't need a new vehicle like Cygnus for every mission. This means that they can keep the cost competitive.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Alpha_Centauri on 01/15/2016 08:01 am
Interesting comment from ESA's boss,

https://mobile.twitter.com/pbdes/status/687917097746329600
Quote
ESA's Woerner: Our long-standing cooperation w/ Sierra Nevada on DreamChaster should expand now that NASA selected it for ISS cargo supply.

Edit: Also,

https://mobile.twitter.com/pbdes/status/687925908997599232
Quote
ESAs Woerner: SNC Dream Chaser wings too big for Ariane launch, but wings could be folded to make it fit. It's feasible.

Which of course it's already being designed to have.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Star One on 01/15/2016 08:16 am
Now that's a nice positive development. Maybe they will be in the market for a manned variant.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: john smith 19 on 01/15/2016 09:42 am
This is an exciting development both for SNC and the CRS programme.

I don't think anyone expected both suppliers to suffer launch failures within weeks of each other and I suspect that's helped get SNC back in the game. Credit to NASA for being able to both consider and accept a return player.

Regarding launch costs keep in mind Orbital launched the last of their CRS1 contract on Atlas V.

Also keep in mind as this is cargo only SNC are saying it could fly on Ariane 5.

This is where it gets too murky for me to penetrate.

Does an Atlas V come under a NASA launch (IE from ULA) or will this be a commercial launch, dealt with by LM ? By definition any deal SNC did with Arianespace is a commercial contract (relative to Arianespace).

As a commercial deal LM might be more willing (and have the ability) to adjust its prices, relative to an LV SNC had to procure under the NASA contract (assuming they would be eligible under that contract).

The same question could be asked for Orbitals' Cygnus  launches on Atlas V.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: rocx on 01/15/2016 09:50 am
This is an exciting development both for SNC and the CRS programme.

I don't think anyone expected both suppliers to suffer launch failures within weeks of each other and I suspect that's helped get SNC back in the game. Credit to NASA for being able to both consider and accept a return player.
They did not. There was three quarters of a year between the ORB-4 failure and the SPx-7 failure.

Quote
Regarding launch costs keep in mind Orbital launched the last of their CRS1 contract on Atlas V.

Also keep in mind as this is cargo only SNC are saying it could fly on Ariane 5.

This is where it gets too murky for me to penetrate.

Does an Atlas V come under a NASA launch (IE from ULA) or will this be a commercial launch, dealt with by LM ? By definition any deal SNC did with Arianespace is a commercial contract (relative to Arianespace).
It will be dealt with by LM.

Quote
As a commercial deal LM might be more willing (and have the ability) to adjust its prices, relative to an LV SNC had to procure under the NASA contract (assuming they would be eligible under that contract).

The same question could be asked for Orbitals' Cygnus  launches on Atlas V.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Lee Jay on 01/15/2016 09:59 am
A question. What is the (numerical) difference in re-entry mission g loads between the DCcargo and a capsule like Starliner and Dragon?

1.5g's versus 4.5g's.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: baldusi on 01/15/2016 12:24 pm
Regarding costs, it's interesting that CRS-2 flights will start by 2019, which, if I'm not mistaken, is the year ULA will transition to OrbitalATK "significantly cheaper" SRB. So, it might just have happened, that OrbitalATK's bid to ULA actually helped make SNC bid to CRS-2 competitive.
Also, if they use Dual Centaur, they would be adding volume to the Crewed Atlas V. They don't need the crew rating of the RL-10A4, but ordering 10 of those Centaurs (Crew and Cargo to ISS) should help with scale.
Also, it looks suspiciously close to Vulcan debut. I'm just saying.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: arachnitect on 01/15/2016 01:24 pm
This is an exciting development both for SNC and the CRS programme.

I don't think anyone expected both suppliers to suffer launch failures within weeks of each other and I suspect that's helped get SNC back in the game. Credit to NASA for being able to both consider and accept a return player.
They did not. There was three quarters of a year between the ORB-4 failure and the SPx-7 failure.

Quote
Regarding launch costs keep in mind Orbital launched the last of their CRS1 contract on Atlas V.

Also keep in mind as this is cargo only SNC are saying it could fly on Ariane 5.

This is where it gets too murky for me to penetrate.

Does an Atlas V come under a NASA launch (IE from ULA) or will this be a commercial launch, dealt with by LM ? By definition any deal SNC did with Arianespace is a commercial contract (relative to Arianespace).
It will be dealt with by LM.

Quote
As a commercial deal LM might be more willing (and have the ability) to adjust its prices, relative to an LV SNC had to procure under the NASA contract (assuming they would be eligible under that contract).

The same question could be asked for Orbitals' Cygnus  launches on Atlas V.

Even though this is a "commercial" launch, ULA will handle it.

LMCLS didn't touch OA-4 or OA-6
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: abaddon on 01/15/2016 03:24 pm
That won't be cheap. Atlas V doesn't get any more expensive than that.
In fact, it will be more expensive than any Atlas V ever (barring cost savings from previous iterations).

I'm really scratching my head how SNC could put in a competitive bid on price given they have a lot of development effort to finish the spacecraft from where CCiCAP left off, and will be launching on by far the most expensive launcher of the bunch.  Which makes me think it wasn't competitive on price and NASA is going to overpay.  Really curious to see how much it's going to cost NASA per launch.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: abaddon on 01/15/2016 03:27 pm
And really do any of know how much a commercially procured Atlas V costs? Orbital doesn't seem to be complaining.
Orbital is using an Atlas V 401 [EDIT: Lars-J correction; thanks!].  That's a) the 4 meter fairing instead of 5 meter, b) zero boosters instead of five, and c) the usual one-engine upper stage, instead of the new two-engine upper stage.

This isn't just a commercially-sold Atlas V, it is the most expensive Atlas V to ever fly.  When the government is buying these, they do not come cheap.  Hard to see how the commercial variant is all of a sudden going to be a great deal.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Lee Jay on 01/15/2016 03:29 pm
That won't be cheap. Atlas V doesn't get any more expensive than that.
In fact, it will be more expensive than any Atlas V ever (barring cost savings from previous iterations).

I'm really scratching my head how SNC could put in a competitive bid on price given they have a lot of development effort to finish the spacecraft from where CCiCAP left off, and will be launching on by far the most expensive launcher of the bunch.  Which makes me think it wasn't competitive on price and NASA is going to overpay.  Really curious to see how much it's going to cost NASA per launch.

Don't forget to divide by the upmass (as much as 5,500kg) and to deduct for not having to build a new spacecraft for each flight.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: abaddon on 01/15/2016 03:36 pm
Don't forget to divide by the upmass (as much as 5,500kg)
Why would I do that?  That was a baseline requirement!
Quote
and to deduct for not having to build a new spacecraft for each flight
Dragon won't be rebuilt either, so no difference there.  Cygnus isn't very expensive and doesn't have to be refurbished.  DreamChaser will still be expending their cargo module (that allows them to achieve that upmass).  In comparison, the Dragon trunk is much cheaper.  At best this is going to be a wash, until you include the amount of money it will take to complete the spacecraft.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Lars-J on 01/15/2016 03:38 pm
And really do any of know how much a commercially procured Atlas V costs? Orbital doesn't seem to be complaining.
Orbital is using an Atlas V 421.  That's a) the 4 meter fairing instead of 5 meter, b) two boosters instead of five, and c) the usual one-engine upper stage, instead of the new two-engine upper stage.

OrbitalATK's Cygnus launched on an Atlas V 401 (0 boosters), not 421.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Lee Jay on 01/15/2016 03:47 pm
Don't forget to divide by the upmass (as much as 5,500kg)
Why would I do that?  That was a baseline requirement!

No, it exceeds the requirement, and is more that Cygnus (max 4,400kg).
Quote
Quote
and to deduct for not having to build a new spacecraft for each flight
Dragon won't be rebuilt either, so no difference there.

So far, they have been employing new Dragons for each mission, and the evidence so far is that recovered Dragons are providing at most components for new build pressure hulls.  Further, it looks so far like reused Dragons will be extensively rebuilt if they are to fly again.

Quote
Cygnus isn't very expensive and doesn't have to be refurbished.

It doesn't have to be refurbished because it burns up in the atmosphere.  And I suspect it's more expensive than you think, including the SM.

Quote
DreamChaser will still be expending their cargo module (that allows them to achieve that upmass).  In comparison, the Dragon trunk is much cheaper.  At best this is going to be a wash, until you include the amount of money it will take to complete the spacecraft.

The DC cargo module is mostly a "dumb" module since the RCS and avionics are in the DC.  The cargo module is probably much, much less expensive (I'd estimate 1/10th) than Cygnus.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: abaddon on 01/15/2016 03:58 pm
Okay, I get it.  DC is cool.  It's worth it no matter what.  Price is no object, OR somehow (magically waves hands) it will be cost-effective despite it not being close to developed yet & launching on a far more expensive launcher.

Look, I'll happily eat my words if we find out DC missions aren't far more expensive than Dragon missions and notably more expensive than Cygnus missions.  I can't see how anyone would think that at this point, but I'm done arguing.

Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Lars-J on 01/15/2016 05:00 pm
DreamChaser will still be expending their cargo module (that allows them to achieve that upmass).  In comparison, the Dragon trunk is much cheaper.  At best this is going to be a wash, until you include the amount of money it will take to complete the spacecraft.

The DC cargo module is mostly a "dumb" module since the RCS and avionics are in the DC.  The cargo module is probably much, much less expensive (I'd estimate 1/10th) than Cygnus.

The module likely won't be that "dumb" (nor cheap), since it is a fully pressurized module (and man-rated) with a hatch on both sides. Think of it as a smaller Cygnus pressurized module.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Lee Jay on 01/15/2016 05:06 pm
DreamChaser will still be expending their cargo module (that allows them to achieve that upmass).  In comparison, the Dragon trunk is much cheaper.  At best this is going to be a wash, until you include the amount of money it will take to complete the spacecraft.

The DC cargo module is mostly a "dumb" module since the RCS and avionics are in the DC.  The cargo module is probably much, much less expensive (I'd estimate 1/10th) than Cygnus.

The module likely won't be that "dumb" (nor cheap), since it is a fully pressurized module (and man-rated) with a hatch on both sides. Think of it as a smaller Cygnus pressurized module.

Without an SM.  I suspect the SM is pretty expensive (engines, tanks, avionics, etc.) compared to an MPLM.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: adrianwyard on 01/15/2016 05:20 pm
Now that DC has a future, it's worth returning to some previously asked questions:

+ What is the main propulsion system (prop and engines). Propanox/Orbitec?
+ What is the RCS? (Both are 'green', so not hydrazine as used by Dragons).
+ How is ISS reboost accomplished - are the (tiny looking) front facing RCS jets capable of doing this?
+ To the untrained eye it looks as though the solar panels on the cargo module will be hit by the plume from the rear facing motors. Incorrect CG?

Anyone hear anything on these topics of late?
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: BrightLight on 01/15/2016 05:23 pm
A question. What is the (numerical) difference in re-entry mission g loads between the DCcargo and a capsule like Starliner and Dragon?

1.5g's versus 4.5g's.
For material science, this difference is substantial, for biolofic materials maybe less so.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Dante80 on 01/15/2016 05:24 pm
As far as I know, the cargo DC does not have any motors. Only RCS.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Danderman on 01/15/2016 05:28 pm
It means that pressurized cargo can go up in the DC or the cargo module, but only down in the DC.


There be dragons there!

The DC and cargo module will be connected by a CBM, per the drawing. That would be the first time that something is launched while attached via a mating adapter. That imposes a lot of loads on the mating adapter (presumably CBM) that it was not designed for.

The alternative is a special design interface between the DC and cargo adapter, but there still has to be a pressurized bulkhead with hatch between them, unless the plan is to cover the DC rear hatch with netting and let the pressurized downmass deal with vacuum for a short time. That pressurized bulkhead would have to support the launch interface and still allow crew to transfer between the DC and cargo module.

Nothing here is a show-stopper, I am just pointing out the special requirements implied by the cartoon.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Lars-J on 01/15/2016 05:33 pm
It means that pressurized cargo can go up in the DC or the cargo module, but only down in the DC.


There be dragons there!

The DC and cargo module will be connected by a CBM, per the drawing. That would be the first time that something is launched while attached via a mating adapter. That imposes a lot of loads on the mating adapter (presumably CBM) that it was not designed for.

The alternative is a special design interface between the DC and cargo adapter, but there still has to be a pressurized bulkhead with hatch between them, unless the plan is to cover the DC rear hatch with netting and let the pressurized downmass deal with vacuum for a short time. That pressurized bulkhead would have to support the launch interface and still allow crew to transfer between the DC and cargo module.

Nothing here is a show-stopper, I am just pointing out the special requirements implied by the cartoon.

The DC to cargo module/trailer is *NOT* a CBM hatch, it is far too small for that. It is likely a custom hatch, but it appears to have the same diameter as an APAS/IDSS hatch. (since that was what Crew DC would have in that spot)
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: john smith 19 on 01/15/2016 05:40 pm
The module likely won't be that "dumb" (nor cheap), since it is a fully pressurized module (and man-rated) with a hatch on both sides. Think of it as a smaller Cygnus pressurized module.
With Moog charging about $100k for an RCS thrust nozzle cluster and BAe charging the same for a processor board?

That structure looks basically like a cylinder with 2 airtight doors to me. And as we know from SX experience man rating is actually pretty cheap if you do your homework and build it in from the start.

TBH calling it a "cargo" vehicle looks like it won't have seats or controls.

IMHO a "crew" DC would be a lot more like a "cargo" DC than the Dragon 2 will be like the cargo Dragon.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: adrianwyard on 01/15/2016 05:43 pm
As far as I know, the cargo DC does not have any motors. Only RCS.

Agreed it is likely to be one system. But it needs to be capable of orbital manuevering, de-orbit burn, and apparently ISS reboost. So more than just attitude control.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Rocket Science on 01/15/2016 06:29 pm
As far as I know, the cargo DC does not have any motors. Only RCS.

Agreed it is likely to be one system. But it needs to be capable of orbital manuevering, de-orbit burn, and apparently ISS reboost. So more than just attitude control.
Adrian, if you recall the Shuttle used it's nose (downward firing) RCS for station reboost. They could use forward facing ones for it. I guess we'll get more details soon if I know the Chris(s)... ;)
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: A_M_Swallow on 01/15/2016 06:53 pm
{snip}
+ To the untrained eye it looks as though the solar panels on the cargo module will be hit by the plume from the rear facing motors. Incorrect CG?


Horizontal solar panels look like wings. They only get deployed in space so they do not have to worry about air resistance. So they could open vertically like a tail fin.

Clearance against the fairing and ISS would need checking for vertical solar panels.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: JBF on 01/16/2016 02:20 am
I'm going to go out on a limb here and predict the DC will be a long term failure.  I have 2 primary arguments.

1.  It is going up encapsulated in a fairing.  That is extra cost and weight.
2.  It has folding wings that add additional complexity, weight and risk.

As a result although it will fly and land it will never be cost effective.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: yg1968 on 01/16/2016 02:23 am
Interesting article on potential ESA-SNC ties:

http://www.bbc.com/news/science-environment-35328544
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Lee Jay on 01/16/2016 02:28 am
I'm going to go out on a limb here and predict the DC will be a long term failure.  I have 2 primary arguments.

1.  It is going up encapsulated in a fairing.  That is extra cost and weight.
2.  It has folding wings that add additional complexity, weight and risk.

As a result although it will fly and land it will never be cost effective.

Though you might have a correct conclusion, I suspect those reasons would have little to do with it.

1.  The fairing situation makes it more-or-less vehicle agnostic.  Any LV with a 5m fairing and sufficient lift can carry it.

2.  Folding wings were pretty much solved in WWII.  They really aren't a big deal at all.  My favorite example is the TBM Avenger.

https://www.youtube.com/watch?v=byfRHbsz60E

Here's an R/C model of an F4U Corsair:

https://www.youtube.com/watch?v=fWhKUfgFWcc
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: rayleighscatter on 01/16/2016 02:32 am
Interesting article on potential ESA-SNC ties:

http://www.bbc.com/news/science-environment-35328544
It's interesting that they were insisting on folded wings since the crewed version was worked out on Atlas V with just an adapter (Hermes on Ariane proposed only an adapter as well).
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: JBF on 01/16/2016 02:35 am
Interesting article on potential ESA-SNC ties:

http://www.bbc.com/news/science-environment-35328544
It's interesting that they were insisting on folded wings since the crewed version was worked out on Atlas V with just an adapter (Hermes on Ariane proposed only an adapter as well).

I have a feeling that they needed to use a fairing due to the external cargo/service module.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Danderman on 01/16/2016 05:37 am
The real takeaway is that there are many ways to get to space, and not just SpaceX or the Shuttle are the only viable options. If there were more money available for bidders, I am sure that more SpaceX type companies would emerge. Hopefully, cheaper prices will spur larger markets for space launch, and things will take off literally.

Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Antilope7724 on 01/16/2016 06:34 am
Why is the cargo module tapered, almost streamlined, when it launches inside a payload fairing? Seems like a waste of possibly available space. Why not a cylinder like the Cygnus pressurized module?
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Rocket Science on 01/16/2016 07:39 am
I'm going to go out on a limb here and predict the DC will be a long term failure.  I have 2 primary arguments.

1.  It is going up encapsulated in a fairing.  That is extra cost and weight.
2.  It has folding wings that add additional complexity, weight and risk.

As a result although it will fly and land it will never be cost effective.
Folding wings were good enough for NASA on the X-38 CRV program. We've discussed this to death over the years, it's fine...

http://www.spaceref.com/news/viewnews.html?id=691http://www.therpf.com/f11/has-anyone-done-hl-10-lifting-body-54417/index4.html
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Star One on 01/16/2016 09:10 am
Being as we are now working on shape changing wings I cannot see how something as old as folding wings is going to be much of an issue.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: JBF on 01/16/2016 12:23 pm
Guys, you are missing my point. I'm not saying Dream Chaser won't work.

If your goal is to move cargo and/or people as cheaply as possible everything you add moves you away from that goal.

Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Rocket Science on 01/16/2016 01:59 pm
Guys, you are missing my point. I'm not saying Dream Chaser won't work.

If your goal is to move cargo and/or people as cheaply as possible everything you add moves you away from that goal.
Then you should look at the "complete delivery system reliability; both Russian and American, as space-craft and or launcher factor into it.

http://www.forbes.com/sites/alexknapp/2015/06/28/with-spacex-rocket-failure-nasas-now-had-three-cargo-failures-from-three-providers/#2715e4857a0b1a4f861b727e
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: yg1968 on 01/16/2016 02:17 pm
This presentation on cargo DC isn't new (it's from last fall) but is worth reposting given recent news:

Here is an interesting presentation on cargo DC.

https://www.youtube.com/watch?v=dNXXzFlJuHQ
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: TrevorMonty on 01/16/2016 02:36 pm
Guys, you are missing my point. I'm not saying Dream Chaser won't work.

If your goal is to move cargo and/or people as cheaply as possible everything you add moves you away from that goal.
All 3 vehicles offer different capabilities and redundancies. DC offers down mass and cargo disposal redundancy to Dragon and Cygnus. It not always about up mass price per kg.

Station reboost, low G reentry and quick access to returned experiments.

As for launch costs, the Vulcan should be considerably cheaper and will be available from 2019.  SNC and NASA will have the option of using it.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: yg1968 on 01/16/2016 03:04 pm
In the presentation that I linked above, Sirangelo says that DC cargo can bring up to 5000kg of pressurized cargo to the ISS.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: yg1968 on 01/16/2016 03:13 pm
Here is the slide which discusses all of the potential LVs for DC Cargo:
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Dante80 on 01/16/2016 03:15 pm
In the presentation that I linked above, Sirangelo says that DC cargo can bring up to 5000kg of pressurized cargo to the ISS.

That should be correct.

The numbers are:

5000kg of pressurized upmass (1750kg on the craft, 3250kg on the storage module).
500kg of unpressurized upmass (two external canisters around the storage module)
3250kg of trash disposal.
1750kg of pressurized downmass.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Danderman on 01/16/2016 03:26 pm
Guys, you are missing my point. I'm not saying Dream Chaser won't work.

If your goal is to move cargo and/or people as cheaply as possible everything you add moves you away from that goal.



We don't know if SNC is intending to make a profit from this contract. It is likely that the goal is to use this contract to pay for testing of the design so that SNC would be in position for future work for human transportation in space. 

Let me fanwank for a moment: without a cargo module or cargo, a crewed DC that would be available after testing of the cargo variant could probably fly on a much smaller (cheaper) LV than Atlas 552, and with lower G forces for re-entry, this could be a viable contender for orbital space tourism, once the DDT&E costs were amortized.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: yg1968 on 01/16/2016 03:28 pm
In the presentation, Sirangelo says that each spacecraft can be used at least 15 times but more likely between 20 and 30 flights.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: yg1968 on 01/16/2016 03:37 pm
In the presentation that I linked above, Sirangelo says that DC cargo can bring up to 5000kg of pressurized cargo to the ISS.

That should be correct.

The numbers are:

5000kg of pressurized upmass (1750kg on the craft, 3250kg on the storage module).
500kg of unpressurized upmass (two external canisters around the storage module)
3250kg of trash disposal.
1750kg of pressurized downmass.

Thanks. Where did you get these numbers from?

Edit: I found the reference for the numbers: http://spacenews.com/sierra-nevada-hopes-dream-chaser-finds-sweet-spot-of-iss-cargo-competition/
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Lee Jay on 01/16/2016 03:40 pm
Guys, you are missing my point. I'm not saying Dream Chaser won't work.

If your goal is to move cargo and/or people as cheaply as possible everything you add moves you away from that goal.

So, things like parachutes, airbags, landing engines, and landing fuel are an obvious no-go, right?
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: BrightLight on 01/16/2016 04:14 pm
Guys, you are missing my point. I'm not saying Dream Chaser won't work.

If your goal is to move cargo and/or people as cheaply as possible everything you add moves you away from that goal.

So, things like parachutes, airbags, landing engines, and landing fuel are an obvious no-go, right?
Since Cygnus has cheap engines, low numbers of ground crew, no parachutes, no airbags, no wings, no landing fuel - it should be the cheapest cargo up-mass system? Hmmmm.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Hauerg on 01/16/2016 04:20 pm
Craft yes, but the launcher is part of the system, so .... No.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: JBF on 01/16/2016 04:31 pm
All engineering is a trade-off between competing goals. In my opinion the design decisions in the current form of the DC do not lend themselves to low cost access to space.  However Danderman makes a good point that at this time it may be more about proving out vehicle.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Star One on 01/16/2016 04:46 pm
All engineering is a trade-off between competing goals. In my opinion the design decisions in the current form of the DC do not lend themselves to low cost access to space.  However Danderman makes a good point that at this time it may be more about proving out vehicle.

Not everything is about the all mighty dollar is the point some are making here. Sometimes watching the bottom line and nothing else is more of a hazard than anything else.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Rocket Science on 01/16/2016 05:00 pm
I'm a big picture guy... I don't really look at individual program cost as it all fall under ISS logistics and the money all comes out of the "same box" of total discretionary funds allocated...
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: yg1968 on 01/16/2016 05:10 pm
NASA also made it clear that it wanted as much cargo as possible in the least amount of missions per year (approximately 4). In other words, NASA was ready to pay a premium for a more capable spacecraft. DC is likely the most capable spacecraft with a capability of 5000 kg of pressurised upmass cargo. Orbital ATK has a capability that is between 3750kg and 4400kg. SpaceX has a capability of at least 3300kg of pressurized cargo with Dragon1.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: dror on 01/16/2016 05:20 pm
Here is the slide which discusses all of the potential LVs for DC Cargo:
The slide says Falcon Heavy, but that was before F9FT.
I wonder if the F9FT can lift the thing up to ISS either as expendable or reusable, if so what would be the price difference compared to Atlas V 552, and would they have opted for F9FT if they knew it was coming.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: yg1968 on 01/16/2016 05:21 pm
Here is the slide which discusses all of the potential LVs for DC Cargo:
The slide says Falcon Heavy, but that was before F9FT.
I wonder if the F9FT can lift the thing up to ISS either as expendable or reusable, if so what would be the price difference compared to Atlas V 552, and would they have opted for F9FT if they knew it was coming.

They knew about F9FT at that point in time (October 2015) eventough it hadn't flown. FH hasn't flown either.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Lars-J on 01/16/2016 05:28 pm
In the presentation, Sirangelo says that each spacecraft can be used at least 15 times but more likely between 20 and 30 flights.

Yes but irrelevant, since SNC is building TWO cargo DCs to cover this contract.

For this contract SNC need to:
- complete development of Cargo DC
- build two cargo DC
- build six expendable cargo pods for every flight (carrying most of the cargo)
- buy six flights of the most expensive Atlas V variant there is

If SNC is not losing money on CRS2, NASA is either paying them a LOT, or there is some very creative accounting involved.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: docmordrid on 01/16/2016 05:31 pm
It means that pressurized cargo can go up in the DC or the cargo module, but only down in the DC.


There be dragons there!

The DC and cargo module will be connected by a CBM, per the drawing. That would be the first time that something is launched while attached via a mating adapter. That imposes a lot of loads on the mating adapter (presumably CBM) that it was not designed for.

The alternative is a special design interface between the DC and cargo adapter, but there still has to be a pressurized bulkhead with hatch between them, unless the plan is to cover the DC rear hatch with netting and let the pressurized downmass deal with vacuum for a short time. That pressurized bulkhead would have to support the launch interface and still allow crew to transfer between the DC and cargo module.

Nothing here is a show-stopper, I am just pointing out the special requirements implied by the cartoon.

The DC to cargo module/trailer is *NOT* a CBM hatch, it is far too small for that. It is likely a custom hatch, but it appears to have the same diameter as an APAS/IDSS hatch. (since that was what Crew DC would have in that spot)

IIRC, DLR was building a Dream Chaser docking adapter under DC4EU. That contract runs through 2017.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: kato on 01/16/2016 05:45 pm
OHB maybe, not DLR. DLR doesn't do anything direct with SNC, and DLR's contract is with OHB.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Robotbeat on 01/16/2016 05:53 pm
Here is the slide which discusses all of the potential LVs for DC Cargo:
The slide says Falcon Heavy, but that was before F9FT.
I wonder if the F9FT can lift the thing up to ISS either as expendable or reusable, if so what would be the price difference compared to Atlas V 552, and would they have opted for F9FT if they knew it was coming.

They knew about F9FT at that point in time (October 2015) eventough it hadn't flown. FH hasn't flown either.
They mention Delta IV, but not Delta IV Heavy. Even the Falcon 9 v1.1 can get MUCH more payload to ISS orbit than the heaviest non-heavy Delta IV Medium+:

Delta IV M+(5,4) 12,820 kg (to 407km, 51.6deg) source: http://www.spacelaunchreport.com/delta4.html

Falcon 9 (v1.1)    15030kg (to 407km, 51.6deg) source: http://elvperf.ksc.nasa.gov/


So either their chart or your reasoning are inconsistent. They mention Falcon Heavy, but not Delta IV Heavy (just Delta IV).

I think they just forgot to mention Falcon 9, or they didn't have the space. There is no reason Falcon 9 couldn't launch Dream Chaser.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Lee Jay on 01/16/2016 05:54 pm
In the presentation, Sirangelo says that each spacecraft can be used at least 15 times but more likely between 20 and 30 flights.

Yes but irrelevant, since SNC is building TWO cargo DCs to cover this contract.

For this contract SNC need to:
- complete development of Cargo DC
- build two cargo DC
- build six expendable cargo pods for every flight (carrying most of the cargo)
- buy six flights of the most expensive Atlas V variant there is
To do the same job, Orbital would have to build 8-10 expendable cargo pods that are much larger, build 8-10 space craft (Cygnus service modules), consume 8-10 launch vehicles, and even then there'd be exactly zero downmass and zero unpressurized upmass.

Quote
If SNC is not losing money on CRS2, NASA is either paying them a LOT, or there is some very creative accounting involved.

NASA should be paying a lot per flight because they're getting a lot of pressurized up mass, a lot of pressurized down mass, a modest amount of unpressurized upmass, and a lot of disposal on every fight.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Robotbeat on 01/16/2016 05:55 pm
Here is the slide which discusses all of the potential LVs for DC Cargo:
The slide says Falcon Heavy, but that was before F9FT.
I wonder if the F9FT can lift the thing up to ISS either as expendable or reusable, if so what would be the price difference compared to Atlas V 552, and would they have opted for F9FT if they knew it was coming.

They knew about F9FT at that point in time (October 2015) eventough it hadn't flown. FH hasn't flown either.
You're making much too big of an implication from a simple lack of something being mention.

Falcon 9 full thrust gets about the same payload to ISS orbit as the variant of Atlas V that SNC is using for CRS-2, and much more than the one they were proposing for commercial crew.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: NovaSilisko on 01/16/2016 05:55 pm
Would Falcon-anything need an extended fairing for DC to fit inside?
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Lee Jay on 01/16/2016 06:04 pm
Would Falcon-anything need an extended fairing for DC to fit inside?

Do they even have a 5m fairing?
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Rocket Science on 01/16/2016 06:10 pm
Hey Lee Jay!

Any chance you could get out to SNC for an exclusive? :)

~Rob
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Lee Jay on 01/16/2016 06:12 pm
Hey Lee Jay!

Any chance you could get out to SNC for an exclusive? :)

~Rob

If they give me an opportunity, I'll go in a flash.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Rocket Science on 01/16/2016 06:13 pm
Hey Lee Jay!

Any chance you could get out to SNC for an exclusive? :)

~Rob

If they give me an opportunity, I'll go in a flash.
Where's the "like" button?? ;D
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: jongoff on 01/16/2016 06:20 pm
In the presentation, Sirangelo says that each spacecraft can be used at least 15 times but more likely between 20 and 30 flights.

Yes but irrelevant, since SNC is building TWO cargo DCs to cover this contract.

For this contract SNC need to:
- complete development of Cargo DC
- build two cargo DC
- build six expendable cargo pods for every flight (carrying most of the cargo)
- buy six flights of the most expensive Atlas V variant there is

If SNC is not losing money on CRS2, NASA is either paying them a LOT, or there is some very creative accounting involved.

Or some things don't cost as much as you're assuming. Don't get me wrong, I'm not very partial to SNC's technical approach, I just think you're stating things with false-certainty.

~Jon
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: NovaSilisko on 01/16/2016 06:23 pm
Would Falcon-anything need an extended fairing for DC to fit inside?

Do they even have a 5m fairing?

Their website says it's 5.2m in diameter, so that part should be fine. I'm more concerned about length...
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Zed_Noir on 01/16/2016 06:24 pm
Would Falcon-anything need an extended fairing for DC to fit inside?

Do they even have a 5m fairing?

The SpaceX standard PLF got a 5.2 meter external diameter with internal diameter of 4.6 meters. The internal height is about 11 meters. IIRC the DC is about 9.15 metere (30 feet) in length.

The Atlas V 5 meter PLF got a 4.57 meter (180 inch) internal diameter.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Dante80 on 01/16/2016 06:27 pm
IIRC the DC is about 9.15 metere (30 feet) in length.

If that is without the storage module, then it would not fit in a Falcon 9 fairing...I think.

Here is an illustration of the fairing. Sadly, we cannot extrapolate from the Atlas V or Ariane5 fairing dimensions, since those come in three length variants each. 
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Lee Jay on 01/16/2016 06:29 pm
Would Falcon-anything need an extended fairing for DC to fit inside?

Do they even have a 5m fairing?

The SpaceX standard PLF got a 5.2 meter external diameter with internal diameter of 4.6 meters. The internal height is about 11 meters. IIRC the DC is about 9.15 metere (30 feet) in length.

The Atlas V 5 meter PLF got a 4.57 meter (180 inch) internal diameter.


The long version of the Atlas V 5 meter fairing is 16.484m long, inside.  So, yeah, length might be an issue for Falcon.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: adrianwyard on 01/16/2016 07:11 pm
Which prompts an interesting question: I wonder if Cargo DC can fly without the cargo module if required/desired.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Star One on 01/16/2016 07:19 pm
I wonder if DC once it proves itself will become the preferred cargo carrier as it very much fits the more for less flight philosophy.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: yg1968 on 01/16/2016 07:54 pm
Here is the slide which discusses all of the potential LVs for DC Cargo:
The slide says Falcon Heavy, but that was before F9FT.
I wonder if the F9FT can lift the thing up to ISS either as expendable or reusable, if so what would be the price difference compared to Atlas V 552, and would they have opted for F9FT if they knew it was coming.

They knew about F9FT at that point in time (October 2015) eventough it hadn't flown. FH hasn't flown either.
You're making much too big of an implication from a simple lack of something being mention.

Falcon 9 full thrust gets about the same payload to ISS orbit as the variant of Atlas V that SNC is using for CRS-2, and much more than the one they were proposing for commercial crew.

Why would they specifically say FH if F9 is sufficient? You are the one assuming that F9 is simply an omission.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: yg1968 on 01/16/2016 07:56 pm
Which prompts an interesting question: I wonder if Cargo DC can fly without the cargo module if required/desired.

Why not? That's how the regular DC will fly.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: yg1968 on 01/16/2016 08:13 pm
IIRC the DC is about 9.15 metere (30 feet) in length.

If that is without the storage module, then it would not fit in a Falcon 9 fairing...I think.

Here is an illustration of the fairing. Sadly, we cannot extrapolate from the Atlas V or Ariane5 fairing dimensions, since those come in three length variants each.

That could be it. According to the Bigelow report (which is dated August 2013), the FH has an extra 15' of fairing lenght (compared to the fairing of the F9).  That could explain why the FH is listed but not the F9.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: adrianwyard on 01/16/2016 08:13 pm
Sorry I should have said 'will fly without the cargo module.' IRL they might not develop and qualify the hardware needed to attach DC directly to the Centaur - even though that's what was intended for Crewed DC.

My question was about whether Cargo DC would actually fly this way for a NASA ordered mission as part of the CRS2 contract.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: yg1968 on 01/16/2016 08:20 pm
Sorry I should have said 'will fly without the cargo module.' IRL they might not develop and qualify the hardware needed to attach DC directly to the Centaur - even though that's what was intended for Crewed DC.

My question was about whether Cargo DC would actually fly this way for a NASA ordered mission as part of the CRS2 contract.

NASA said at the CRS2 presser that SNC only has two types of missions. One docks and the other one berths to the ISS. Both of these types of missions are shown in the SNC video and both have the trailer. Kirk Shireman also said that both mission types had unpressurized disposal which also implies that both have the trailer.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Lars-J on 01/16/2016 09:44 pm
In the presentation, Sirangelo says that each spacecraft can be used at least 15 times but more likely between 20 and 30 flights.

Yes but irrelevant, since SNC is building TWO cargo DCs to cover this contract.

For this contract SNC need to:
- complete development of Cargo DC
- build two cargo DC
- build six expendable cargo pods for every flight (carrying most of the cargo)
- buy six flights of the most expensive Atlas V variant there is

If SNC is not losing money on CRS2, NASA is either paying them a LOT, or there is some very creative accounting involved.

Or some things don't cost as much as you're assuming. Don't get me wrong, I'm not very partial to SNC's technical approach, I just think you're stating things with false-certainty.

~Jon

Oh I know I don't have certainty... But something smells off about this. For development costs, SpaceX and Orbital both had COTS to spread out development over. SNC benefited from some commercial crew funding, but they still have quite a bit of development work remaining.

My suspicion - again, suspicion - is that the SNC contract is substantially larger than the SpaceX and OrbitalATK contracts, and this happened because there are certain elements within NASA that are very much attached to the idea of winged spacecraft. :)

Just to be clear, I'm not posting all this because I want to see DC fail. I like seeing contrasting ideas for spacecraft design battle it out to determine the best approach. But there is something about this that just seems a bit strange.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Lars-J on 01/16/2016 09:51 pm
I wonder if DC once it proves itself will become the preferred cargo carrier as it very much fits the more for less flight philosophy.

More for less of what? For the "more" part, by itself (without cargo pod/trailer), DC has a rather anemic cargo capacity. (1.75 metric ton of pressurized up and down mass) The additional cargo capacity forces it to use the 2nd largest launcher in ULA's arsenal. And since most of the cargo is carried in an *expendable* component, the claimed reuse figures aren't as impressive as otherwise thought.

As for the "less" part - we still don't know the actual cost of each flight.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: yg1968 on 01/16/2016 10:46 pm
He meant more cargo on less flights. Not the price.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: yg1968 on 01/16/2016 11:25 pm
Interesting article on DC in Satellite Today magazine.

Mark Sirangelo says that are working on a profile that would have the first DC reach orbit in 2018.

http://www.satellitetoday.com/launch/2015/03/31/sierra-nevada-corporation-details-future-dream-chaser-mission-concepts/

It also touches on international developments for DC.

Hmm... It seems that in March 2015. Sirangelo said that the upgraded F9 could potentially work for cargo DC.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Jcc on 01/16/2016 11:40 pm
Guys, you are missing my point. I'm not saying Dream Chaser won't work.

If your goal is to move cargo and/or people as cheaply as possible everything you add moves you away from that goal.



We don't know if SNC is intending to make a profit from this contract. It is likely that the goal is to use this contract to pay for testing of the design so that SNC would be in position for future work for human transportation in space. 

Let me fanwank for a moment: without a cargo module or cargo, a crewed DC that would be available after testing of the cargo variant could probably fly on a much smaller (cheaper) LV than Atlas 552, and with lower G forces for re-entry, this could be a viable contender for orbital space tourism, once the DDT&E costs were amortized.

Being encapsulated inside a faring might not be appropriate for human flights, so they may have to go back to a design that can fly without a faring.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Star One on 01/16/2016 11:58 pm

He meant more cargo on less flights. Not the price.

Thank yes that was my point. I am not sure considering  price alone would give you the reason for DC being chosen.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Rocket Science on 01/17/2016 12:45 am
Do we know which building will house Dream Chaser at KSC? Still at O&C with LM and Orion?
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Robotbeat on 01/17/2016 01:05 am
Here is the slide which discusses all of the potential LVs for DC Cargo:
The slide says Falcon Heavy, but that was before F9FT.
I wonder if the F9FT can lift the thing up to ISS either as expendable or reusable, if so what would be the price difference compared to Atlas V 552, and would they have opted for F9FT if they knew it was coming.

They knew about F9FT at that point in time (October 2015) eventough it hadn't flown. FH hasn't flown either.
You're making much too big of an implication from a simple lack of something being mention.

Falcon 9 full thrust gets about the same payload to ISS orbit as the variant of Atlas V that SNC is using for CRS-2, and much more than the one they were proposing for commercial crew.

Why would they specifically say FH if F9 is sufficient? You are the one assuming that F9 is simply an omission.
Why would they say Delta IV (not Delta IV Heavy) if the Delta IV mediums were all insufficient?
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Antilope7724 on 01/17/2016 01:15 am
Guys, you are missing my point. I'm not saying Dream Chaser won't work.

If your goal is to move cargo and/or people as cheaply as possible everything you add moves you away from that goal.



We don't know if SNC is intending to make a profit from this contract. It is likely that the goal is to use this contract to pay for testing of the design so that SNC would be in position for future work for human transportation in space. 

Let me fanwank for a moment: without a cargo module or cargo, a crewed DC that would be available after testing of the cargo variant could probably fly on a much smaller (cheaper) LV than Atlas 552, and with lower G forces for re-entry, this could be a viable contender for orbital space tourism, once the DDT&E costs were amortized.

Being encapsulated inside a faring might not be appropriate for human flights, so they may have to go back to a design that can fly without a faring.

The tapered cargo module/attachment point seems like it was more designed for a outside airflow than the interior launch environment of a payload faring.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Dante80 on 01/17/2016 01:31 am
Why would they say Delta IV (not Delta IV Heavy) if the Delta IV mediums were all insufficient?

This is getting to be a guesswork game. In any case, maybe a Delta IV-M+(5,4) has the fairing length and the power to carry it. Maybe F9FT can do it, maybe it cannot due to a small fairing.

Who knows.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Robotbeat on 01/17/2016 01:43 am
Why would they say Delta IV (not Delta IV Heavy) if the Delta IV mediums were all insufficient?

This is getting to be a guesswork game. In any case, maybe a Delta IV-M+(5,4) has the fairing length and the power to carry it. Maybe F9FT can do it, maybe it cannot due to a small fairing.

Who knows.
There's no real good reason you couldn't use the longer Falcon Heavy fairing on a Falcon 9 (with some relatively minor modifications), if that's really the hold-up.

I agree, it's a guesswork game. Which is why I object to the claim that this says that Falcon 9 won't work.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: yg1968 on 01/17/2016 02:43 am
In March 2015, Sirangelo said that it could potentially be done with the upgraded F9. Maybe that's what he meant. It could be done but it wouldn't be easy. Maybe that's why they listed the FH but not the F9 in October. 
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Lars-J on 01/17/2016 06:22 am
Being encapsulated inside a faring might not be appropriate for human flights, so they may have to go back to a design that can fly without a faring.

It is a *certainty* that being encapsulated in a fairing would be a big NO for a crewed DC.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: okan170 on 01/17/2016 08:15 am
The tapered cargo module/attachment point seems like it was more designed for a outside airflow than the interior launch environment of a payload faring.

It kind of looks like it was designed to allow clearance for the RCS plumes.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Rocket Science on 01/17/2016 12:31 pm
The tapered cargo module/attachment point seems like it was more designed for a outside airflow than the interior launch environment of a payload faring.

It kind of looks like it was designed to allow clearance for the RCS plumes.
Or future engine bells... ;)
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: BrightLight on 01/17/2016 09:55 pm
Does anyone know if the cargo pod can be used with the manned version of the DC? 
Does adding the cargo pod require a fairing?
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Dante80 on 01/17/2016 10:16 pm
Does anyone know if the cargo pod can be used with the manned version of the DC? 
Does adding the cargo pod require a fairing?

It could. If I remember correctly, DC had a pretty elaborate (in shape) adaptor for mating with the Centaur stage. Maybe something similar could work with mating the cargo pod, maybe not.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Rocket Science on 01/17/2016 10:33 pm
I'm not certain that Dream Chaser with the cargo pod could handle the aero-loads without a faring... That would be asking a lot from the hatch interfaces. They could still do it with a support frame adapter to the back of DC around the pod from Centaur and cover the whole works with a small faring...
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: adrianwyard on 01/17/2016 11:13 pm
And remember even with the stock Crewed DC adapter there is a little room inside the fairing; smaller unpressurized cargo could be placed there. The trick is to not obstruct docking.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: adrianwyard on 01/17/2016 11:23 pm
The tapered cargo module/attachment point seems like it was more designed for a outside airflow than the interior launch environment of a payload faring.

It kind of looks like it was designed to allow clearance for the RCS plumes.
Or future engine bells... ;)

The plume from the small jets on the very outside of Cargo DC look like it'll clear the cargo module, just. But I'm not sure about anything larger or more inboard... You don't want to fry the cargo module, even if it is expendable.  :o
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Antilope7724 on 01/18/2016 05:12 am
I'm not certain that Dream Chaser with the cargo pod could handle the aero-loads without a faring... That would be asking a lot from the hatch interfaces. They could still do it with a support frame adapter to the back of DC around the pod from Centaur and cover the whole works with a small faring...

If the cargo pod is not blocking thrusters, etc, why not use a pressurized cylinder similar to Cygnus? It would give more volume for light, bulky items. At 5,000kg it has the lift capacity, but volume may be lacking with the tapered cargo pod.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Rocket Science on 01/18/2016 08:44 am
The tapered cargo module/attachment point seems like it was more designed for a outside airflow than the interior launch environment of a payload faring.

It kind of looks like it was designed to allow clearance for the RCS plumes.
Or future engine bells... ;)

The plume from the small jets on the very outside of Cargo DC look like it'll clear the cargo module, just. But I'm not sure about anything larger or more inboard... You don't want to fry the cargo module, even if it is expendable.  :o
Agreed, it would need a thermal shield/barrier for certain...
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Rocket Science on 01/18/2016 08:51 am
I'm not certain that Dream Chaser with the cargo pod could handle the aero-loads without a faring... That would be asking a lot from the hatch interfaces. They could still do it with a support frame adapter to the back of DC around the pod from Centaur and cover the whole works with a small faring...

If the cargo pod is not blocking thrusters, etc, why not use a pressurized cylinder similar to Cygnus? It would give more volume for light, bulky items. At 5,000kg it has the lift capacity, but volume may be lacking with the tapered cargo pod.
I could seed a few crewed standard DC docking to a Cygnus module if ever needed... Like the Orbital X-24 to MOL.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Todd Martin on 01/18/2016 01:32 pm
Being encapsulated inside a faring might not be appropriate for human flights, so they may have to go back to a design that can fly without a faring.

It is a *certainty* that being encapsulated in a fairing would be a big NO for a crewed DC.

I believe current fairing designs are not appropriate for crewed missions because:
1) Crew need to enter the spacecraft relatively late in the launch preparations, not days before.
2) Fairings do not allow for pad abort of the spacecraft in cases of emergency on the pad.
3) Fairings do not allow for in flight abort of the spacecraft prior to jettison of the fairing.

Since fighter jet aircraft have ejection seats which work even though the pilot is inside an enclosed cockpit, I can imagine a fairing designed to allow for each of these contingencies.

1) The fairing has a hatch allowing crew to transfer late into the spacecraft.
2) The fairing has explosive bolts that quickly separate the fairing, exposing the space-craft for ejection during pad abort or in-flight abort.

Does anyone know if design work has been done on a fairing allowing for crew?  I'm thinking this is more a cost issue than being physically impossible, unless I'm missing something.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: rayleighscatter on 01/18/2016 02:29 pm
It could also, in theory, abort through the fairing. Some ejection seat systems already do this, explosive charges that simply blow apart a clear path.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Rocket Science on 01/18/2016 02:39 pm
Being encapsulated inside a faring might not be appropriate for human flights, so they may have to go back to a design that can fly without a faring.

It is a *certainty* that being encapsulated in a fairing would be a big NO for a crewed DC.

I believe current fairing designs are not appropriate for crewed missions because:
1) Crew need to enter the spacecraft relatively late in the launch preparations, not days before.
2) Fairings do not allow for pad abort of the spacecraft in cases of emergency on the pad.
3) Fairings do not allow for in flight abort of the spacecraft prior to jettison of the fairing.

Since fighter jet aircraft have ejection seats which work even though the pilot is inside an enclosed cockpit, I can imagine a fairing designed to allow for each of these contingencies.

1) The fairing has a hatch allowing crew to transfer late into the spacecraft.
2) The fairing has explosive bolts that quickly separate the fairing, exposing the space-craft for ejection during pad abort or in-flight abort.

Does anyone know if design work has been done on a fairing allowing for crew?  I'm thinking this is more a cost issue than being physically impossible, unless I'm missing something.
Only in the movie Marooned Todd... Nothing that defies the laws of physics, it's always just about time and money... ;)

See our friend Ron's work here and excellent as usual modelling skills! 8)

https://forum.nasaspaceflight.com/index.php?topic=37935.0

Edit to add: Apollo had a launch escape boost cover over the CM...
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: TrevorMonty on 01/18/2016 02:50 pm
Rocket Science Orbital X24 just goes to show a lot of these new commercial vehicle concepts are not new ideas. Most of these concepts were worked on and studied decades ago but never resulted in flight HW. Must be rewarding for the original engineers to see all their hard work being resurrected and actually fly.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Rocket Science on 01/18/2016 02:55 pm
Rocket Science Orbital X24 just goes to show a lot of these new commercial vehicle concepts are not new ideas. Most of these concepts were worked on and studied decades ago but never resulted in flight HW. Must be rewarding for the original engineers to see all their hard work being resurrected and actually fly.
I  agree Trevor, especially the late Dale Reed and all the other greybeards are smiling somewhere... :)

~Rob
http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19980169231.pdf
http://www.nasa.gov/topics/technology/features/hl20-recognition.html
https://www.youtube.com/watch?v=7MKOZbwGuls
Where is the like button? ;D
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: adrianwyard on 01/18/2016 03:12 pm
It could also, in theory, abort through the fairing. Some ejection seat systems already do this, explosive charges that simply blow apart a clear path.

I'm not certain I 'Like' this, but I'd love to see video of it in use! Something tells me that if your means to save the crew involves surrounding them with explosives, you might want to look for alternatives?  :) At high dynamic pressure/speed would't shards be blown into the vehicle by the airstream? Better to have a mechanical force that shoves the fairing halves aside. Or not put DC in a fairing...
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Rocket Science on 01/18/2016 03:17 pm
It could also, in theory, abort through the fairing. Some ejection seat systems already do this, explosive charges that simply blow apart a clear path.

I'm not certain I 'Like' this, but I'd love to see video of it in use! Something tells me that if your means to save the crew involves surrounding them with explosives, you might want to look for alternatives?  :) At high dynamic pressure/speed would't shards be blown into the vehicle by the airstream? Better to have a mechanical force that shoves the fairing halves aside. Or not put DC in a fairing...
Or a an Apollo-like LES boost /cover or faring that would pull DC free from a bottom mount and then separate from the vehicle...
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: adrianwyard on 01/18/2016 03:39 pm
Good point. As does Soyuz. Which brings up a very good question: Are the motors we think will be fitted to a crewed DC* even capable of abort performance? If not, then a tractor system like Apollo/Soyuz would have to be added.

* Last we heard SNC had ditched the hybrids and bought Orbitec, which has successfully flown Propane+Lox motors.

They've recently tested 30Klb Propane/Kerosene/NOx/LOx motors. I'd love to know if two of those are suitable for abort of a ~10mT DC. http://orbitec.com/documents/ORBITEC_30k_VORTEX_engine_press_release_final.pdf

http://www.gizmag.com/orbitec-vortex-liquid-fuel-rocket-engine/24807/

https://www.youtube.com/watch?v=5piqTvDzKvY
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Rocket Science on 01/18/2016 03:48 pm
Good point. As does Soyuz. Which brings up a very good question: Are the motors we think will be fitted to a crewed DC* even capable of abort performance? If not, then a tractor system like Apollo/Soyuz would have to be added.

* Last we heard SNC had ditched the hybrids and bought Orbitec, which has successfully flown Propane+Lox motors:

http://www.gizmag.com/orbitec-vortex-liquid-fuel-rocket-engine/24807/

It would solve the aero-load and abort, but with a mass penalty... All the would need then is the similar OMS as is being proposed for the Cargo DC for orbit/de-orbit...
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: rayleighscatter on 01/18/2016 03:52 pm
It could also, in theory, abort through the fairing. Some ejection seat systems already do this, explosive charges that simply blow apart a clear path.

I'm not certain I 'Like' this, but I'd love to see video of it in use! Something tells me that if your means to save the crew involves surrounding them with explosives, you might want to look for alternatives?  :) At high dynamic pressure/speed would't shards be blown into the vehicle by the airstream? Better to have a mechanical force that shoves the fairing halves aside. Or not put DC in a fairing...
It hasn't been tried to the scale of a spacecraft fairing as far as I'm aware, and there probably are better methods (the best still being not having it in a fairing). But it has been demonstrated with fighter jets.

https://www.youtube.com/watch?v=6QRwCvfBRM0

https://www.youtube.com/watch?v=L0m6UEFaWvE

https://www.youtube.com/watch?v=0xa7C1Bu3w0
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Rocket Science on 01/18/2016 03:58 pm
Problem is the seats are large, heavy, take up a lot space and use explosives. They are also limited in usefulness in the flight envelope(see Gemini). Why not save the entire spacecraft for reuse, it is meant to fly as a glider and land...
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: adrianwyard on 01/18/2016 04:05 pm
I just noticed that in the SNC Orbitec press release they mention they are working on 65Klb and 75Klb motors. However these are using Hydrogen or Methane and LOx so probably not bound for Dream Chaser. This would however, be the right size for SS2, and two of these would match the abort specs that SpaceX has on their Dragon 2 with SuperDracos.

http://www.sncorp.com/AboutUs/NewsDetails/2242
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Rocket Science on 01/18/2016 04:12 pm
I just noticed that in the SNC Orbitec press release they mention they are working on 65Klb and 75Klb motors. However these are using Hydrogen or Methane and LOx so probably not bound for Dream Chaser. This would however, be the right size for SS2, and two of these would match the abort specs that SpaceX has on their Dragon 2 with SuperDracos.

http://www.sncorp.com/AboutUs/NewsDetails/2242
My only concern with non-solid, non-hypergolic  is the ramp-up time to full thrust for abort use... I would need to see them demonstrated as fail-safe...
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: TrevorMonty on 01/18/2016 04:14 pm
I just noticed that in the SNC Orbitec press release they mention they are working on 65Klb and 75Klb motors. However these are using Hydrogen or Methane and LOx so probably not bound for Dream Chaser. This would however, be the right size for SS2, and two of these would match the abort specs that SpaceX has on their Dragon 2 with SuperDracos.

http://www.sncorp.com/AboutUs/NewsDetails/2242
Or for ULA ACES.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: adrianwyard on 01/18/2016 04:31 pm
I just noticed that in the SNC Orbitec press release they mention they are working on 65Klb and 75Klb motors. However these are using Hydrogen or Methane and LOx so probably not bound for Dream Chaser. This would however, be the right size for SS2, and two of these would match the abort specs that SpaceX has on their Dragon 2 with SuperDracos.

http://www.sncorp.com/AboutUs/NewsDetails/2242
My only concern with non-solid, non-hypergolic  is the ramp-up time to full thrust for abort use... I would need to see them demonstrated as fail-safe...

I suppose you could bolt on some solid abort rocket where we have seen the hybrid engine bells depicted before now. Perhaps even release them once you reach orbit, making them similar to the Mercury retrorocket pack. Once in orbit Crewed DC would use the exact same low-thrust, green, storable propellant system that will be proven on Cargo DC.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Lobo on 01/18/2016 04:47 pm
Remember, it looks like they are basing this cargo DC on their original crew DC prototype, with a few tweaks.

They would share the same OML and basic configuration.  Just adding folding wing tips, and the playload module under it, and removing the on board abort engines and windows, etc.

So, if the original DC was going to be able to launch unenclosed...and all indicators were that it would...then I would think there's no reason they couldn't just make a crew version of this if funding ever materialized for it, and just launch it unenclosed.

The payload module could be changed to be the abort motor, as it was for the HL-42 (and I think HL-20, but not for sure if it's LES motors were external like HL-42 or internal).  So the DC wouldn't need to have abort motors integrated back into it.  That should save a lot of development work to make DC carry crew if there becomes a nee for it down the road.  Which is I'm sure what SN is hoping will happen.

Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Rocket Science on 01/18/2016 04:51 pm
I just noticed that in the SNC Orbitec press release they mention they are working on 65Klb and 75Klb motors. However these are using Hydrogen or Methane and LOx so probably not bound for Dream Chaser. This would however, be the right size for SS2, and two of these would match the abort specs that SpaceX has on their Dragon 2 with SuperDracos.

http://www.sncorp.com/AboutUs/NewsDetails/2242
My only concern with non-solid, non-hypergolic  is the ramp-up time to full thrust for abort use... I would need to see them demonstrated as fail-safe...

I suppose you could bolt on some solid abort rocket where we have seen the hybrid engine bells depicted before now. Perhaps even release them once you reach orbit, making them similar to the Mercury retrorocket pack. Once in orbit Crewed DC would use the exact same low-thrust, green, storable propellant system that will be proven on Cargo DC.
Or back to this without a faring... ;D

http://dscb.larc.nasa.gov/DCBStaff/ebj/OnePagers/HL20abort.html

Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Rocket Science on 01/18/2016 05:41 pm
Remember, it looks like they are basing this cargo DC on their original crew DC prototype, with a few tweaks.

They would share the same OML and basic configuration.  Just adding folding wing tips, and the playload module under it, and removing the on board abort engines and windows, etc.

So, if the original DC was going to be able to launch unenclosed...and all indicators were that it would...then I would think there's no reason they couldn't just make a crew version of this if funding ever materialized for it, and just launch it unenclosed.

The payload module could be changed to be the abort motor, as it was for the HL-42 (and I think HL-20, but not for sure if it's LES motors were external like HL-42 or internal).  So the DC wouldn't need to have abort motors integrated back into it.  That should save a lot of development work to make DC carry crew if there becomes a nee for it down the road.  Which is I'm sure what SN is hoping will happen.
They were the same on the HL-20 Lobo, external on the adapter...

http://www2.coe.pku.edu.cn/tpic/2011721145939517.pdf

The whole faring talk started about launching Dream Chaser with crew and cargo module as in CRS-2...

Edit to add:
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: DAZ on 01/18/2016 06:43 pm
The question is not how to do an abort with a lifting body/winged vehicle it is what to do after you do the abort.  It is not like a capsule where you just pop out the parachute and flopped down someplace.  Like almost all things having to do with this it was looked at extensively in the 60s.

An abort late in the launch would require a reentry but as you are already in a reentry vehicle this was not considered much of a problem.  So an abort here is considered a straightforward relatively simple engineering problem.

An abort at Max Q is a little bit more complicated but was still considered a straightforward engineering problem as the vehicle is designed to fly in this regime as long as it is released in a controllable manner.  There is also a sufficient time to consider where to fly to make a landing.

The question that gave the engineers some problem was what to do following an abort off the launchpad.  The vehicle would find itself heading straight up and somewhat away from its landing location.  It would also be relatively low so they would not be much energy nor time to carry out any maneuver.  They could not come up with a relatively straightforward answer so they gave the problem to an aeronautical engineer/test pilot who was working on the X-20 project at the time.

To the test pilot this look like the 2nd step in an Immelmann maneuver so this is where he thought he would start.  Going straight up the 1st thing they would do is roll to their back so their back was to the direction of the entrance to the approach to the runway.  It would then pull back and be inverted were they would then continue on until they were approximately lined up with the runway and would continue over and down making a turn to line up with the runway.  If the whole maneuver was performed correctly they would then be on a normal approach and landing.

The rocket engineers had some doubt that this Armstrong maneuver could be carried out automatically or more importantly in manual mode by the pilots.  They thought they would be too disoriented and the maneuver would be too complicated to pull off.  They also had some doubts as to the energy states available and whether or not it was even physically aerodynamically possible to pull off the maneuver.

The test pilot’s solution to this problem was he would just fly it and prove that it could be done.  He picked a fighter aircraft with a low lift to drag ratio similar to a reentry winged/lift body vehicle.  He would then come in very low to the ground and fast.  At the appropriate point that would simulate the launchpad he would pull up hard, chopping the throttle to flight idle, until he was vertical.  This would simulate the disorienting effects and leave the aircraft with approximately the same energy state and traveling in the same direction as an aborted vehicle.  He would then perform the Armstrong maneuver.  At the end of which he would make a dead stick landing just like the aborted vehicle would need to make.  Reportedly the test pilot did this multiple times to show that just about any well-qualified trained pilot could safely and reliably perform the maneuver.

To my knowledge this is the only time this was really looked at.  With the engineering paper in hand in the procedure tested with test flights the rocket engineers were satisfied with the results.  Really though the whole thing comes down to as to whether or not you trust the work of the aeronautical/test pilot who did this.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Lobo on 01/18/2016 06:57 pm

They were the same on the HL-20 Lobo, external on the adapter...

http://www2.coe.pku.edu.cn/tpic/2011721145939517.pdf

The whole faring talk started about launching Dream Chaser with crew and cargo module as in CRS-2...

Edit to add:

I figured that would be the case, but my quick Google-fu failed to turn up anything definite.  Just some references saying that the LES would push HL-20 off the booster.  But not if the motors were part of the HL-20 structure or external like the HL-42.

So thanks for that confirmation.

So in reference to DC, I think it would be relatively easy to do something similar in place of the aft payload carrier if there was money/desire to make the cargo DC into a crew DC.  They wouldn't need to mess with the ship itself too much, other than internals like ECLSS. 

And like the HL-20, it would do double duty as LV adaptor and LES, as it would be launching unenclosed.
Then the whole thing is jettisoned once in orbit, as it would have been for HL-20, exposing the docking port, for docking with a space station.

So more truly an HL-20, potentially.


Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Lobo on 01/18/2016 07:04 pm
The question is not how to do an abort with a lifting body/winged vehicle it is what to do after you do the abort.  It is not like a capsule where you just pop out the parachute and flopped down someplace.  Like almost all things having to do with this it was looked at extensively in the 60s.

An abort late in the launch would require a reentry but as you are already in a reentry vehicle this was not considered much of a problem.  So an abort here is considered a straightforward relatively simple engineering problem.

An abort at Max Q is a little bit more complicated but was still considered a straightforward engineering problem as the vehicle is designed to fly in this regime as long as it is released in a controllable manner.  There is also a sufficient time to consider where to fly to make a landing.

The question that gave the engineers some problem was what to do following an abort off the launchpad.  The vehicle would find itself heading straight up and somewhat away from its landing location.  It would also be relatively low so they would not be much energy nor time to carry out any maneuver.  They could not come up with a relatively straightforward answer so they gave the problem to an aeronautical engineer/test pilot who was working on the X-20 project at the time.

To the test pilot this look like the 2nd step in an Immelmann maneuver so this is where he thought he would start.  Going straight up the 1st thing they would do is roll to their back so their back was to the direction of the entrance to the approach to the runway.  It would then pull back and be inverted were they would then continue on until they were approximately lined up with the runway and would continue over and down making a turn to line up with the runway.  If the whole maneuver was performed correctly they would then be on a normal approach and landing.

The rocket engineers had some doubt that this Armstrong maneuver could be carried out automatically or more importantly in manual mode by the pilots.  They thought they would be too disoriented and the maneuver would be too complicated to pull off.  They also had some doubts as to the energy states available and whether or not it was even physically aerodynamically possible to pull off the maneuver.

The test pilot’s solution to this problem was he would just fly it and prove that it could be done.  He picked a fighter aircraft with a low lift to drag ratio similar to a reentry winged/lift body vehicle.  He would then come in very low to the ground and fast.  At the appropriate point that would simulate the launchpad he would pull up hard, chopping the throttle to flight idle, until he was vertical.  This would simulate the disorienting effects and leave the aircraft with approximately the same energy state and traveling in the same direction as an aborted vehicle.  He would then perform the Armstrong maneuver.  At the end of which he would make a dead stick landing just like the aborted vehicle would need to make.  Reportedly the test pilot did this multiple times to show that just about any well-qualified trained pilot could safely and reliably perform the maneuver.

To my knowledge this is the only time this was really looked at.  With the engineering paper in hand in the procedure tested with test flights the rocket engineers were satisfied with the results.  Really though the whole thing comes down to as to whether or not you trust the work of the aeronautical/test pilot who did this.

Daz,

Nice info there.

I think for the HL-20, the plan for a pad abort was to have parachutes and flotation bags that would deploy for a water landing off sure, as was the case for the capsules.

From Astroanutix:

Quote
The design of the HL-20 PLS concept had taken into account crew safety and survivability for various abort modes. The interior layout with a ladder and hatch arrangement was designed to permit rapid egress of passengers and crew for emergencies on the launch pad. For on-the-pad emergencies or during launch where time was a critical element (launch vehicle fire or explosion), the HL-20 would be equipped with emergency escape rockets that would rapidly thrust the PLS away from the booster. The method was similar to that used during the Apollo program. Once at a safe distance, a cluster of three emergency parachutes would open to lower the vehicle to a safe ocean landing. Inflatable flotation devices ensured that it rode high in the water, with at least one of two hatches available for crew emergency egress.

Although it sounds like a good pilot could handle a an emergency landing to the runway there from what you posted.  So maybe they could verify that with a crew DC to see the difficulties in it. 
But the parachutes isn't a bad method.  Like with D2, it'd retain it's parachutes and could always use them as a backup landing method in case there's ever need to ditch in the ocean.  Whether for launch abort, or a problem during EDL.
The X-38 Crew Return Vehicle would have used a parasail to land gently on a dry lake bed.  So even emergency ground landing would be possible, depending on the type (and mass) of the parachute system.  If you used a parasail or a more traditional ringslot chute system like capsules.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: arachnitect on 01/18/2016 07:10 pm
I'm not certain that Dream Chaser with the cargo pod could handle the aero-loads without a faring... That would be asking a lot from the hatch interfaces. They could still do it with a support frame adapter to the back of DC around the pod from Centaur and cover the whole works with a small faring...

If the cargo pod is not blocking thrusters, etc, why not use a pressurized cylinder similar to Cygnus? It would give more volume for light, bulky items. At 5,000kg it has the lift capacity, but volume may be lacking with the tapered cargo pod.

Tapered cargo pod leaves more room for solar arrays and unpressurized cargo under the fairing.

The tapered pod also transfers the spacecraft's weight to the LV more efficiently.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: DAZ on 01/18/2016 07:23 pm
Airbags and parachutes might be the better option.  Although airbags and parachutes add weight and complexity which may not be necessary if the vehicle can do it without them.  Sierra Nevada has a plan for a manned version of the DC.  To the best of my knowledge neither the man version nor the cargo version has any parachutes.  I have not seen any plans or discussions to add parachutes to the DC.  Parachutes and airbags are also something that would be an entirely separate test line item to be accomplished.  So the question is not how do we think this low altitude abort should be accomplished but how is Sierra Nevada planning on accomplishing this?
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Rocket Science on 01/18/2016 07:34 pm
The question is not how to do an abort with a lifting body/winged vehicle it is what to do after you do the abort.  It is not like a capsule where you just pop out the parachute and flopped down someplace.  Like almost all things having to do with this it was looked at extensively in the 60s.

An abort late in the launch would require a reentry but as you are already in a reentry vehicle this was not considered much of a problem.  So an abort here is considered a straightforward relatively simple engineering problem.

An abort at Max Q is a little bit more complicated but was still considered a straightforward engineering problem as the vehicle is designed to fly in this regime as long as it is released in a controllable manner.  There is also a sufficient time to consider where to fly to make a landing.

The question that gave the engineers some problem was what to do following an abort off the launchpad.  The vehicle would find itself heading straight up and somewhat away from its landing location.  It would also be relatively low so they would not be much energy nor time to carry out any maneuver.  They could not come up with a relatively straightforward answer so they gave the problem to an aeronautical engineer/test pilot who was working on the X-20 project at the time.

To the test pilot this look like the 2nd step in an Immelmann maneuver so this is where he thought he would start.  Going straight up the 1st thing they would do is roll to their back so their back was to the direction of the entrance to the approach to the runway.  It would then pull back and be inverted were they would then continue on until they were approximately lined up with the runway and would continue over and down making a turn to line up with the runway.  If the whole maneuver was performed correctly they would then be on a normal approach and landing.

The rocket engineers had some doubt that this Armstrong maneuver could be carried out automatically or more importantly in manual mode by the pilots.  They thought they would be too disoriented and the maneuver would be too complicated to pull off.  They also had some doubts as to the energy states available and whether or not it was even physically aerodynamically possible to pull off the maneuver.

The test pilot’s solution to this problem was he would just fly it and prove that it could be done.  He picked a fighter aircraft with a low lift to drag ratio similar to a reentry winged/lift body vehicle.  He would then come in very low to the ground and fast.  At the appropriate point that would simulate the launchpad he would pull up hard, chopping the throttle to flight idle, until he was vertical.  This would simulate the disorienting effects and leave the aircraft with approximately the same energy state and traveling in the same direction as an aborted vehicle.  He would then perform the Armstrong maneuver.  At the end of which he would make a dead stick landing just like the aborted vehicle would need to make.  Reportedly the test pilot did this multiple times to show that just about any well-qualified trained pilot could safely and reliably perform the maneuver.

To my knowledge this is the only time this was really looked at.  With the engineering paper in hand in the procedure tested with test flights the rocket engineers were satisfied with the results.  Really though the whole thing comes down to as to whether or not you trust the work of the aeronautical/test pilot who did this.
It's all been studied... No worries...

http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19940030181.pdf

http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/20040090517.pdf
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: BrightLight on 01/18/2016 07:59 pm
The reason I was asking about the DC manned version with the cargo pod is a number of DOD missions could be performed with a payload carrier either left in orbit or destroyed on re-entry while the manned portion comes home.
and
Why use a X-37 when you have a cargo DC operational?
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: kato on 01/18/2016 08:06 pm
The whole fairing discussion makes me wonder if one couldn't simply adapt the fairing instead of the vehicle inside for an early abort - in order to minimize design impact on the vehicle. Add some parachutes to the fairing, and an abort rocket adapter between stack and payload/fairing. Use the fairing itself as a crushable structure on ground impact, backed up with airbags.

Gotta lose the fairing -  now considerable heavier, i'd think somewhere around 2 tons fairing weight - as early as possible on the way up though to still have a useful payload, made easier by the fact that the DC would still be mostly aerodynamic unlike other payloads.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Lobo on 01/18/2016 10:15 pm

It's all be studied... No worries...

http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19940030181.pdf

http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/20040090517.pdf

Ahhh, interesting.   I didn't see any parachutes mentioned there.  The post abort maneuvering only.  So DC should be able to do the same thing as it's a kissing cousin.   Just don't know if SN would stick with some sort of internal LAS motors like the original hybrid ones?  Or opt for the HL-20's outboard solid motors?

Too bad they can't really use hypergolic ones like superdracos, that way the whole LAS system itself could be retained and reused.  They -could- but then they'd have to forego their "safe immediately" condition on the ground as they wanted I would think.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Lee Jay on 01/18/2016 10:28 pm
Too bad they can't really use hypergolic ones like superdracos, that way the whole LAS system itself could be retained and reused.  They -could- but then they'd have to forego their "safe immediately" condition on the ground as they wanted I would think.

When I visited them those years ago, they implied it was important that they use ethanol and nitrous.  That way, if a crew had to make an emergency landing in a far-off location, they'd be *very* happy while they awaited rescue, having large quantities of 200 proof alcohol and laughing gas on hand.

;-)
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Zed_Noir on 01/18/2016 11:12 pm
It could also, in theory, abort through the fairing. Some ejection seat systems already do this, explosive charges that simply blow apart a clear path.

I'm not certain I 'Like' this, but I'd love to see video of it in use! Something tells me that if your means to save the crew involves surrounding them with explosives, you might want to look for alternatives?  :) At high dynamic pressure/speed would't shards be blown into the vehicle by the airstream? Better to have a mechanical force that shoves the fairing halves aside. Or not put DC in a fairing...

Well there was the supersonic escape pod for individual crew on the B-58 Hustler bomber. Or the supersonic crew escape capsule in the F111/FB111 bomber and the B-1A bomber prototype.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Lars-J on 01/18/2016 11:39 pm
I've always been skeptical about Crew DC's abort capability - primarily for ocean ditching. If they had a plan for it, they certainly never released it publicly.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Lobo on 01/18/2016 11:41 pm
Too bad they can't really use hypergolic ones like superdracos, that way the whole LAS system itself could be retained and reused.  They -could- but then they'd have to forego their "safe immediately" condition on the ground as they wanted I would think.

When I visited them those years ago, they implied it was important that they use ethanol and nitrous.  That way, if a crew had to make an emergency landing in a far-off location, they'd be *very* happy while they awaited rescue, having large quantities of 200 proof alcohol and laughing gas on hand.

;-)

Ha!

Can they even make viable abort motors with those liquids?  That could react fast and reliable enough?
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Lee Jay on 01/18/2016 11:43 pm
I've always been skeptical about Crew DC's abort capability - primarily for ocean ditching. If they had a plan for it, they certainly never released it publicly.

They thought they could land at an airport from any point in the launch.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Rocket Science on 01/18/2016 11:54 pm
I've always been skeptical about Crew DC's abort capability - primarily for ocean ditching. If they had a plan for it, they certainly never released it publicly.

They thought they could land at an airport from any point in the launch.
Here you go Lee Jay! ;)
http://www.americaspace.com/?p=86264
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: DAZ on 01/19/2016 12:04 am

It's all been studied... No worries...

http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19940030181.pdf

http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/20040090517.pdf

These reports definitely seem to validate the original work performed in the late 50s early 60s.  Not that the person doing the original study was known as a hack.  He did go on to do some significant work in the aerospace industry later on.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Lars-J on 01/19/2016 12:14 am
I've always been skeptical about Crew DC's abort capability - primarily for ocean ditching. If they had a plan for it, they certainly never released it publicly.

They thought they could land at an airport from any point in the launch.
Here you go Lee Jay! ;)

Well, that's... optimistic. And assumes that they will ever only launch to ISS. Nor have a sudden need for an emergency de-orbit.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: adrianwyard on 01/19/2016 12:20 am
I've always been skeptical about Crew DC's abort capability - primarily for ocean ditching. If they had a plan for it, they certainly never released it publicly.

A long time ago I suggested - tongue firmly in cheek - that for water landings they lower the front skid, and not the main gear. Hey presto: DC water skis!
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Rocket Science on 01/19/2016 12:48 am
I've always been skeptical about Crew DC's abort capability - primarily for ocean ditching. If they had a plan for it, they certainly never released it publicly.

They thought they could land at an airport from any point in the launch.
Here you go Lee Jay! ;)

Well, that's... optimistic. And assumes that they will ever only launch to ISS.
It's the only game in town for now... You got someplace else to go?
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Lars-J on 01/19/2016 12:59 am
Well, that's... optimistic. And assumes that they will ever only launch to ISS.
It's the only game in town for now... You got someplace else to go?
Eventually, yes. And it would be nice to have a crew vehicle that did not prevent it. But maybe I'm looking too far forward in the future.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: freakdog on 01/19/2016 01:03 am
Certainly the plan has been stated to produce a crewed DC, and quickly, and for that DC to be sold as an on-demand science lab for whomever is willing to pay for it.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Rocket Science on 01/19/2016 01:11 am
Well, that's... optimistic. And assumes that they will ever only launch to ISS.
It's the only game in town for now... You got someplace else to go?
Eventually, yes. And it would be nice to have a crew vehicle that did not prevent it. But maybe I'm looking too far forward in the future.
I'm good with LEO... You keep havin' those Mars dreams Lars...
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Lars-J on 01/19/2016 01:21 am
Well, that's... optimistic. And assumes that they will ever only launch to ISS.
It's the only game in town for now... You got someplace else to go?
Eventually, yes. And it would be nice to have a crew vehicle that did not prevent it. But maybe I'm looking too far forward in the future.
I'm good with LEO... You keep havin' those Mars dreams Lars...
LEO is not limited to 51.6 degree inclination.  :)
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Rocket Science on 01/19/2016 01:25 am
Well, that's... optimistic. And assumes that they will ever only launch to ISS.
It's the only game in town for now... You got someplace else to go?
Eventually, yes. And it would be nice to have a crew vehicle that did not prevent it. But maybe I'm looking too far forward in the future.
I'm good with LEO... You keep havin' those Mars dreams Lars...
LEO is not limited to 51.6 degree inclination.  :)
Blame it on the Russians...
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Lee Jay on 01/19/2016 01:35 am
I've always been skeptical about Crew DC's abort capability - primarily for ocean ditching. If they had a plan for it, they certainly never released it publicly.

They thought they could land at an airport from any point in the launch.
Here you go Lee Jay! ;)

Well, that's... optimistic. And assumes that they will ever only launch to ISS. Nor have a sudden need for an emergency de-orbit.

The claim also included an emergency deorbit from ISS to a first-world runway in no more than 6 hours, and usually under 2 hours.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Antilope7724 on 01/19/2016 03:17 am
I've always been skeptical about Crew DC's abort capability - primarily for ocean ditching. If they had a plan for it, they certainly never released it publicly.

A long time ago I suggested - tongue firmly in cheek - that for water landings they lower the front skid, and not the main gear. Hey presto: DC water skis!

Sounds like the Convair XF-2Y Sea Dart. A jet fighter that took off and landed in the water on a single ski on the belly. They actually made a working prototype and tested it.

F2Y Sea Dart: "Convair XF-2Y Sea Dart Final Report" circa 1953-57 US Navy
https://youtu.be/oT4H6PLNdww
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: yg1968 on 01/19/2016 03:32 am
I've always been skeptical about Crew DC's abort capability - primarily for ocean ditching. If they had a plan for it, they certainly never released it publicly.

On the Spaceshow (in answer to my questions), Sirangelo said that crewed DC could land in the ocean if necessary.  I asked him if DC could use parachutes in an abort scenario. He didn't answer that question. He said that the information was proprietary.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: adrianwyard on 01/19/2016 05:28 am
I've always been skeptical about Crew DC's abort capability - primarily for ocean ditching. If they had a plan for it, they certainly never released it publicly.

A long time ago I suggested - tongue firmly in cheek - that for water landings they lower the front skid, and not the main gear. Hey presto: DC water skis!

Sounds like the Convair XF-2Y Sea Dart. A jet fighter that took off and landed in the water on a single ski on the belly. They actually made a working prototype and tested it.

F2Y Sea Dart: "Convair XF-2Y Sea Dart Final Report" circa 1953-57 US Navy
https://youtu.be/oT4H6PLNdww

Fascinating. That looks a great deal better than the HL-10 scale model water landing test:

https://www.youtube.com/watch?v=cDr60tsKUHk

(Starts at ~9m30s)
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Antilope7724 on 01/19/2016 07:11 am
I wouldn't want to experience any of those HL-10 water landings.  :o The Sea Dart looks like fun, too bad it never went anywhere. With planes like that, who needs aircraft carriers? Smaller ships could carry it around and place it in the water.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Rocket Science on 01/19/2016 01:13 pm
We talking about this again? :o It has been discussed "ad nauseam" on old the older Dream Chaser threads... The "search" function is your friend... ;)

See here as well: Lifting Body Q&A as well... :)

http://forum.nasaspaceflight.com/index.php?topic=29126.0
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: abaddon on 01/19/2016 01:38 pm
It might be a good idea to have a separate thread for Crew Dream Chaser, so the Discussion & Updates thread can stay focused on the cargo version that SNC will be bringing on line.  (Barring any new news about the Crew version, which I think is going to be sparse at best).
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: yg1968 on 01/19/2016 02:37 pm
An article based on Friday's teleconference on DC:
http://www.defensedaily.com/sierra-nevada-sets-sights-on-crew-opportunities-after-cargo-resupply-services-2-award/

Quote
Sierra Nevada Space Systems Corporate Vice President Mark Sirangelo told reporters Friday during a teleconference that NASA has an “on-ramp” to bring on additional vehicles for crew if they meet certain criteria. NASA spokeswoman Stephanie Schierholz confirmed this Friday.

See post above. It wil be interesting to see if such an on-ramp agreement is concluded between SNC and NASA. SNC's CCiCap agreement has been extended but not all the way to certification. My guess is that NASA and SNC could decide to extend SNC's CCiCap agreement all the way to certification on an unfunded basis.

http://www.sncorp.com/AboutUs/NewsDetails/941
http://www.nasaspaceflight.com/2015/03/nasa-agrees-dream-chaser-development-cdr/
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: yg1968 on 01/19/2016 02:52 pm
The dates on the slides aren't up to date but here are SNC's remaining CCiCap milestones as of today:

Quote
SNC (CCiCap)

Extended SNC’s CCiCap period of performance to March 2016

- The final funded CCiCap milestone, Engineering Test Article Flight Testing #2, was rescheduled to December 2015
- As part of the extension an unfunded milestone was added, Design Analysis Cycle-6 Closeout Review – November 2015

See slide 4:
http://www.nasa.gov/sites/default/files/files/CSD_Brief_to_NAC_Apr_2015.pdf
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: b ramsey on 01/19/2016 03:46 pm
My question is the cargo vs the crew version in launch configuration. The cargo version has the wings fold up and the whole vehicle fits inside a fairing. It's not clear how the crew version will be configured. I'm assuming the crew Dream Chaser will not be put inside a fairing for launch escape reasons, but haven't seen it mentioned in any of these recent SNC articles?
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: rayleighscatter on 01/19/2016 04:21 pm
My question is the cargo vs the crew version in launch configuration. The cargo version has the wings fold up and the whole vehicle fits inside a fairing. It's not clear how the crew version will be configured. I'm assuming the crew Dream Chaser will not be put inside a fairing for launch escape reasons, but haven't seen it mentioned in any of these recent SNC articles?
It will sit open on top of the rocket connected by a launch adapter.

https://www.youtube.com/watch?v=YFgzhtRujTE
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Danderman on 01/20/2016 01:34 am
And now for a little historical context ..................................

SpaceDev Announces SpaceDev Dream Chaser(TM) Space Transport System

http://www.businesswire.com/news/home/20051116005546/en/SpaceDev-Announces-SpaceDev-Dream-Chaser-TM-Space

POWAY, Calif.--(BUSINESS WIRE)--Nov. 16, 2005--SpaceDev (OTCBB: SPDV) announced today its concept for the SpaceDev Dream Chaser(TM) vehicle, a six-passenger human space transport system based on the ten-passenger HL-20 Personnel Launch System developed by NASA Langley. SpaceDev believes its SpaceDev Dream Chaser(TM) can meet the needs of the rapidly emerging commercial space tourism market, and NASA needs for routine, safe and affordable crew access to the International Space Station. SpaceDev believes SpaceDev Dream Chaser(TM) will be much faster and far less expensive to develop than a new crew launch vehicle as proposed by large aerospace companies.

The design concept for the SpaceDev Dream Chaser(TM), which is the same size but lighter than the ten-passenger NASA HL-20 vehicle, is also suitable for safe, affordable sub-orbital space tourism applications. The long-term SpaceDev Dream Chaser(TM) design plan includes a scaled-up version of SpaceDev's non-explosive, rubber-burning hybrid rocket motors. SpaceDev's proprietary hybrid rocket motor technology successfully powered Paul Allen's SpaceShipOne on its historic X Prize winning flights to space last year. To lower risk and cost, the SpaceDev Dream Chaser(TM) system is anticipated to combine existing and proven designs and technologies.

"When our focus was on supporting the development of suborbital space tourism two years ago, SpaceDev engineers selected the NASA X-34 vehicle design which was good for suborbital," said Jim Benson, SpaceDev's founding chairman and chief executive. "Since then, national focus has changed to a Shuttle replacement, and we believe that our new SpaceDev Dream Chaser(TM) vehicle concept is ideal for both suborbital and orbital applications. However, funding is needed if we are going to be able to pursue this exciting new concept."
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: QuantumG on 01/20/2016 01:38 am
It's like suborbital spaceflight and NASA are in a race.. like the tortoise and the turtle.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Robotbeat on 01/20/2016 02:41 am
It's like suborbital spaceflight and NASA are in a race.. like the tortoise and the turtle.
Ouch, but on point. :)
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Patchouli on 01/21/2016 05:33 pm
It's like suborbital spaceflight and NASA are in a race.. like the tortoise and the turtle.


I'd consider SNC vs Spacex a tortoise and the hare race.

Spacex is flying sooner but SNC might have a vehicle better suited for LEO operations and space tourism.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: yg1968 on 01/21/2016 08:56 pm
Why would DC be better suited than Dragon2 for LEO operations and space tourism?
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Patchouli on 01/21/2016 11:54 pm
Why would DC be better suited than Dragon2 for LEO operations and space tourism?
A couple of reasons.
The  low g reentry means more people will be able to pass the physical and it would be a more comfortable ride.
Non toxic propellants would simplify ground operations.
The landed vehicle can be approached without the need for hazmat suits.
Cargo and crew are immediately accessible.
It's landing mode is less likely to damage the both the TPS and the surface it lands on.
Because it has non toxic propellants and a landing mode similar to an airliner getting permission to use a landing site would be a lot easier.
Even Starliner may have an easier time with environmental regulations due to the smaller propellant load in the descent vehicle.
More cross range means it has more return opportunities then a ballistic vehicle which makes it better for medical evacuations.
It's easier to launch the vehicle with an attached mission module making it better suited for free flight missions.

Dragon is still a better BLEO vehicle.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: yg1968 on 01/22/2016 03:27 am
Rare interview with the co-owner of SNC, Fatih Ozmen:

http://www.bloomberg.com/news/videos/2016-01-22/sierra-nevada-the-new-star-shaking-up-the-space-race

At the end of interview, the co-owner of SNC, Fatih Ozmen, mentions that they are looking for strategic and financial partners for DC. I think that Paul Allen would make a lot of sense as an investor in DC. He apparently really likes DC.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: A8-3 on 01/22/2016 02:34 pm
I'm fascinated by this quote in Aviation Week.
Quote
“We’re viewing this program very much like an airliner program, where you can have a passenger version, a cargo version, a military variant, a firefighting variant,” says Sirangelo


What is a "firefighting variant"?

http://aviationweek.com/space/landing-spacecraft-back-earth-will-open-orbital-market (http://aviationweek.com/space/landing-spacecraft-back-earth-will-open-orbital-market)

Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: woods170 on 01/22/2016 03:03 pm
ESA to provide the IBDM for Dream Chaser

http://spacenews.com/europe-to-invest-in-sierra-nevadas-dream-chaser-cargo-vehicle/
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: yg1968 on 01/22/2016 03:25 pm
I'm fascinated by this quote in Aviation Week.
Quote
“We’re viewing this program very much like an airliner program, where you can have a passenger version, a cargo version, a military variant, a firefighting variant,” says Sirangelo


What is a "firefighting variant"?

http://aviationweek.com/space/landing-spacecraft-back-earth-will-open-orbital-market (http://aviationweek.com/space/landing-spacecraft-back-earth-will-open-orbital-market)

No he means for planes, you can have various various types of planes. It's similar with DC. But DC obviously doesn't have a military or a firefighting variant. It has a scientific variants, a cargo variant, a crew variant, etc.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: rpapo on 01/22/2016 03:28 pm
...DC obviously doesn't have a military ... variant.
With the X-37 around, that's possible.  But I wouldn't count it out indefinitely.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: yg1968 on 01/22/2016 03:30 pm
ESA to provide the IBDM for Dream Chaser

http://spacenews.com/europe-to-invest-in-sierra-nevadas-dream-chaser-cargo-vehicle/

SNC gets the first IBDM for free from ESA. They get disposed after each flight. So, hoperfully, they are not too expensive for subsequent flights.

It's a very versatile birthing/docking mechanism:
https://en.wikipedia.org/wiki/International_Berthing_and_Docking_Mechanism
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Nibb31 on 01/22/2016 07:44 pm
IBDM/IDS or whatever it's called, seems to be a pretty expensive piece of kit. On DC, it's expendable. On Dragon, they bring it back.

Does SpaceX reuse the CBM on the Cargo Dragon ?
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: TrevorMonty on 01/22/2016 07:51 pm
Given ESA interest in Dream Chaser I thought they may consider man rating the Ariane 6. Even if not man rated day one now is the time to allow for in the design.

Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Lars-J on 01/22/2016 07:58 pm
IBDM/IDS or whatever it's called, seems to be a pretty expensive piece of kit. On DC, it's expendable. On Dragon, they bring it back.

Does SpaceX reuse the CBM on the Cargo Dragon ?

They probably reuse some internal components, but the exterior is exposed to the re-entry environment, so probably not? In Dragon 2, however, the docking adapter will be hidden behind the nose cone which should make it much easier to reuse.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: woods170 on 01/22/2016 08:42 pm
Given ESA interest in Dream Chaser I thought they may consider man rating the Ariane 6. Even if not man rated day one now is the time to allow for in the design.


Manrating is not in the requirements.  And unlikely to be any time soon given the additional cost.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: yg1968 on 01/23/2016 02:41 am
Here is an article on Orbitec and DC:

Quote
Orbitec will produce the environmental control system that handles air and heat inside the Dream Chaser and rocket engine thrusters that will propel and steer the vehicle in space, Zamprelli said.

“We are extremely proud of the rocket engine development for Sierra Nevada that was started in Madison and tested in our large engine test site at the (former) Badger Ammunition Depot” near Baraboo, he said.

http://host.madison.com/wsj/business/orbitec-to-fly-high-in-sierra-nevada-s-dream-chaser/article_3b9aa641-e3ce-5d7e-8ead-da4908bd2c30.html
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Danderman on 01/24/2016 12:13 am
which gets us back to Stratolaunch and DC and some rocket stage, which I suspect has been done to death here before.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: yg1968 on 01/24/2016 06:43 pm
I noticed on the cargo DC video that the propulsion thrusters at the back of DC are much smaller than the one on the crewed DC video. There is three small thrusters on each side of the back of DC. The propulsion thrusters almost look like RCS thrusters.  I imagine that the new smaller thrusters are the Orbitec thrusters and the one in the crewed DC are the previous hybrid thrusters.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: okan170 on 01/24/2016 08:31 pm
I noticed on the cargo DC video that the propulsion thrusters at the back of DC are much smaller than the one on the crewed DC video. There is three small thrusters on each side of the back of DC. The propulsion thrusters almost look like RCS thrusters.  I imagine that the new smaller thrusters are the Orbitec thrusters and the one in the crewed DC are the previous hybrid thrusters.

I've been doing a bit of research on DC (for 3D purposes) and as far as I can tell, it looks like they're the RCS nozzles.  Perhaps the full Orbitec OMS thrusters may not be present at all on the Cargo version, maybe due to the lack of need for crew abort?
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Rocket Science on 01/24/2016 08:45 pm
I noticed on the cargo DC video that the propulsion thrusters at the back of DC are much smaller than the one on the crewed DC video. There is three small thrusters on each side of the back of DC. The propulsion thrusters almost look like RCS thrusters.  I imagine that the new smaller thrusters are the Orbitec thrusters and the one in the crewed DC are the previous hybrid thrusters.

I've been doing a bit of research on DC (for 3D purposes) and as far as I can tell, it looks like they're the RCS nozzles.  Perhaps the full Orbitec OMS thrusters may not be present at all on the Cargo version, maybe due to the lack of need for crew abort?
I've been thinking about this as well and at this point my conclusion is that the bulk of the work will be done by the DEC. I'm still not convinced though and I'm still thinking some form of OMS....
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: rayleighscatter on 01/24/2016 09:41 pm
If DC is proposing ISS boost with its RCS the RCS may be more capable than most people seem to think, at least in terms of boosting its self.

On the whole though, I agree with Okan, they were removed with no need for abort.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Rocket Science on 01/24/2016 11:07 pm
If DC is proposing ISS boost with its RCS the RCS may be more capable than most people seem to think, at least in terms of boosting its self.

On the whole though, I agree with Okan, they were removed with no need for abort.
I would agree, no need... The 6 rear facing RCS should suffice for deorbit burn...
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: yg1968 on 01/24/2016 11:15 pm
Thanks for the comments. As a comparaison, crewed DC only has 2 small RCS thrusters on each side in the crewed DC video.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: yg1968 on 01/26/2016 10:23 pm
Here is an article on DC:

http://www.geekwire.com/2016/nasas-backing-fuels-more-interest-in-dream-chaser-space-plane/

Quote
The financial terms have yet to be nailed down, but in his interviews, Sirangelo says there’s a general sense that a contract for at least six spaceflights should be worth at least a billion dollars, if not more.
[...]
So what now? Later this year, a Dream Chaser prototype will be put through its second aerodynamic test glide through the atmosphere
[...]
For the upcoming test, the prototype will be dropped from a helicopter, Sirangelo said. After that, the atmospheric tests will be conducted at higher altitudes, using a carrier system that has yet to be identified.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Rocket Science on 01/27/2016 06:28 am
I posted this on the Update thread: Dream Chaser simulator NASA photo. Looks like air tow to launch behind C-17...Hmm... ;) This may be what comes after SkyCrane drop tests that Mark Sirangelo was being cagey about... 8)

Hah, maybe he read my post about air tow 4 years back behind a C-17... ;D

http://forum.nasaspaceflight.com/index.php?topic=30574.40

https://www.nasa.gov/center/armstrong/multimedia/imagegallery/Simulator/ED14-0009-03.html

Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Nibb31 on 01/27/2016 12:22 pm
Given ESA interest in Dream Chaser I thought they may consider man rating the Ariane 6. Even if not man rated day one now is the time to allow for in the design.

Ariane 5 is nearing EOL as launcher, to be replaced with Ariane 6. There won't be any major development investiment in Ariane 5 at this stage in its life cycle.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: adrianwyard on 01/27/2016 06:26 pm
I posted this on the Update thread: Dream Chaser simulator NASA photo. Looks like air tow to launch behind C-17...Hmm... ;) This may be what comes after SkyCrane drop tests that Mark Sirangelo was being cagey about... 8)

Hah, maybe he read my post about air tow 4 years back behind a C-17... ;D

http://forum.nasaspaceflight.com/index.php?topic=30574.40

https://www.nasa.gov/center/armstrong/multimedia/imagegallery/Simulator/ED14-0009-03.html

Since NASA is now seriously invested in DC flying I wonder if the Shuttle Carrier Aircraft might be an option too. Apparently N911NA is doing airshows at the moment, so evidently still flying.

I'm no expert but towing a ~10mT lifting body behind a C-17 seems like the sort of thing that's dead easy and safe in the 95% case, but I can picture trouble with turbulence and/or wake if you happen to get unlucky.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Rocket Science on 01/27/2016 07:37 pm
I posted this on the Update thread: Dream Chaser simulator NASA photo. Looks like air tow to launch behind C-17...Hmm... ;) This may be what comes after SkyCrane drop tests that Mark Sirangelo was being cagey about... 8)

Hah, maybe he read my post about air tow 4 years back behind a C-17... ;D

http://forum.nasaspaceflight.com/index.php?topic=30574.40

https://www.nasa.gov/center/armstrong/multimedia/imagegallery/Simulator/ED14-0009-03.html

Since NASA is now seriously invested in DC flying I wonder if the Shuttle Carrier Aircraft might be an option too. Apparently N911NA is doing airshows at the moment, so evidently still flying.

I'm no expert but towing a ~10mT lifting body behind a C-17 seems like the sort of thing that's dead easy and safe in the 95% case, but I can picture trouble with turbulence and/or wake if you happen to get unlucky.
I guess they could go dig out the 'old Pontiac"... ;D
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: RanulfC on 01/27/2016 08:16 pm
I posted this on the Update thread: Dream Chaser simulator NASA photo. Looks like air tow to launch behind C-17...Hmm... ;) This may be what comes after SkyCrane drop tests that Mark Sirangelo was being cagey about... 8)

Hah, maybe he read my post about air tow 4 years back behind a C-17... ;D

http://forum.nasaspaceflight.com/index.php?topic=30574.40

https://www.nasa.gov/center/armstrong/multimedia/imagegallery/Simulator/ED14-0009-03.html

That looks like a vector line rather than a tow-line actually :) And the aircraft offhand I'd say is a C5 not a C17, could the DC fit into a C5?

Randy
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Rocket Science on 01/27/2016 08:29 pm
I posted this on the Update thread: Dream Chaser simulator NASA photo. Looks like air tow to launch behind C-17...Hmm... ;) This may be what comes after SkyCrane drop tests that Mark Sirangelo was being cagey about... 8)

Hah, maybe he read my post about air tow 4 years back behind a C-17... ;D

http://forum.nasaspaceflight.com/index.php?topic=30574.40

https://www.nasa.gov/center/armstrong/multimedia/imagegallery/Simulator/ED14-0009-03.html

That looks like a vector line rather than a tow-line actually :) And the aircraft offhand I'd say is a C5 not a C17, could the DC fit into a C5?

Randy
I see a C-17 winglet on the right wing... No matter the "the 5" will do it...
IIRC last time I checked a few years back it would not fit unless you removed the wings... Now if they only folded.... ;D
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: RanulfC on 01/27/2016 09:13 pm
I posted this on the Update thread: Dream Chaser simulator NASA photo. Looks like air tow to launch behind C-17...Hmm... ;) This may be what comes after SkyCrane drop tests that Mark Sirangelo was being cagey about... 8)

Hah, maybe he read my post about air tow 4 years back behind a C-17... ;D

http://forum.nasaspaceflight.com/index.php?topic=30574.40

https://www.nasa.gov/center/armstrong/multimedia/imagegallery/Simulator/ED14-0009-03.html

That looks like a vector line rather than a tow-line actually :) And the aircraft offhand I'd say is a C5 not a C17, could the DC fit into a C5?

Randy
I see a C-17 winglet on the right wing... No matter the "the 5" will do it...
IIRC last time I checked a few years back it would not fit unless you removed the wings... Now if they only folded.... ;D

Would folding wings require them to change the name from DC to "Dove" or "Doppelganger" then? :)

Randy
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: rayleighscatter on 01/27/2016 10:38 pm
Here is an article on DC:

http://www.geekwire.com/2016/nasas-backing-fuels-more-interest-in-dream-chaser-space-plane/

Quote
The financial terms have yet to be nailed down, but in his interviews, Sirangelo says there’s a general sense that a contract for at least six spaceflights should be worth at least a billion dollars, if not more.
[...]
So what now? Later this year, a Dream Chaser prototype will be put through its second aerodynamic test glide through the atmosphere
[...]
For the upcoming test, the prototype will be dropped from a helicopter, Sirangelo said. After that, the atmospheric tests will be conducted at higher altitudes, using a carrier system that has yet to be identified.
Is this the first time SNC actually said they were building two orbital vehicles for it? (Or had I just not noticed before?)
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Rocket Science on 01/27/2016 10:44 pm
Here is an article on DC:

http://www.geekwire.com/2016/nasas-backing-fuels-more-interest-in-dream-chaser-space-plane/

Quote
The financial terms have yet to be nailed down, but in his interviews, Sirangelo says there’s a general sense that a contract for at least six spaceflights should be worth at least a billion dollars, if not more.
[...]
So what now? Later this year, a Dream Chaser prototype will be put through its second aerodynamic test glide through the atmosphere
[...]
For the upcoming test, the prototype will be dropped from a helicopter, Sirangelo said. After that, the atmospheric tests will be conducted at higher altitudes, using a carrier system that has yet to be identified.
Is this the first time SNC actually said they were building two orbital vehicles for it? (Or had I just not noticed before?)
I don't recall it before either... Anybody else?
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: baldusi on 01/27/2016 11:12 pm
Here is an article on DC:

http://www.geekwire.com/2016/nasas-backing-fuels-more-interest-in-dream-chaser-space-plane/

Quote
The financial terms have yet to be nailed down, but in his interviews, Sirangelo says there’s a general sense that a contract for at least six spaceflights should be worth at least a billion dollars, if not more.
[...]
So what now? Later this year, a Dream Chaser prototype will be put through its second aerodynamic test glide through the atmosphere
[...]
For the upcoming test, the prototype will be dropped from a helicopter, Sirangelo said. After that, the atmospheric tests will be conducted at higher altitudes, using a carrier system that has yet to be identified.
Is this the first time SNC actually said they were building two orbital vehicles for it? (Or had I just not noticed before?)
I don't recall it before either... Anybody else?
I believe I've seen it before... it might have been on L2.  ;)
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Rocket Science on 01/28/2016 12:02 am
Here is an article on DC:

http://www.geekwire.com/2016/nasas-backing-fuels-more-interest-in-dream-chaser-space-plane/

Quote
The financial terms have yet to be nailed down, but in his interviews, Sirangelo says there’s a general sense that a contract for at least six spaceflights should be worth at least a billion dollars, if not more.
[...]
So what now? Later this year, a Dream Chaser prototype will be put through its second aerodynamic test glide through the atmosphere
[...]
For the upcoming test, the prototype will be dropped from a helicopter, Sirangelo said. After that, the atmospheric tests will be conducted at higher altitudes, using a carrier system that has yet to be identified.
Is this the first time SNC actually said they were building two orbital vehicles for it? (Or had I just not noticed before?)
I don't recall it before either... Anybody else?
I believe I've seen it before... it might have been on L2.  ;)
It sucks getting old! ;D
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Rocket Science on 01/28/2016 01:43 am
Fun little video on what might have been...

https://www.youtube.com/watch?v=TTWVP7j61v0
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Lars-J on 01/28/2016 05:06 pm
Here is an article on DC:

http://www.geekwire.com/2016/nasas-backing-fuels-more-interest-in-dream-chaser-space-plane/

Quote
The financial terms have yet to be nailed down, but in his interviews, Sirangelo says there’s a general sense that a contract for at least six spaceflights should be worth at least a billion dollars, if not more.
[...]
So what now? Later this year, a Dream Chaser prototype will be put through its second aerodynamic test glide through the atmosphere
[...]
For the upcoming test, the prototype will be dropped from a helicopter, Sirangelo said. After that, the atmospheric tests will be conducted at higher altitudes, using a carrier system that has yet to be identified.
Is this the first time SNC actually said they were building two orbital vehicles for it? (Or had I just not noticed before?)

I've seen it mentioned before. I think NASA insisted on it, to make sure they could handle the loss of one vehicle.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: yg1968 on 01/28/2016 08:54 pm
Here is an article on DC:

http://www.geekwire.com/2016/nasas-backing-fuels-more-interest-in-dream-chaser-space-plane/

Quote
The financial terms have yet to be nailed down, but in his interviews, Sirangelo says there’s a general sense that a contract for at least six spaceflights should be worth at least a billion dollars, if not more.
[...]
So what now? Later this year, a Dream Chaser prototype will be put through its second aerodynamic test glide through the atmosphere
[...]
For the upcoming test, the prototype will be dropped from a helicopter, Sirangelo said. After that, the atmospheric tests will be conducted at higher altitudes, using a carrier system that has yet to be identified.
Is this the first time SNC actually said they were building two orbital vehicles for it? (Or had I just not noticed before?)

SNC mentionned it in a post-CRS2 press conference that there would be two cargo DC.

Quote
Sirangelo: current plan is to built two Dream Chasers, in series, to meet cargo mission requirements.
https://twitter.com/jeff_foust/status/688069211860647937
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: JAFO on 01/31/2016 09:07 am
If you can tow a F-106 behind a C-141......

(http://c141heaven.info/dotcom/61/61-2775/612775_eclipse001.jpg)


http://www.f-106deltadart.com/eclipse.htm

https://www.youtube.com/watch?v=9vzB33WPeus (https://www.youtube.com/watch?v=9vzB33WPeus)


BTW, Mark Stucky, the F-106 pilot, is now a pilot for Virgin Galactic.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Rocket Science on 02/01/2016 01:00 am
If you can tow a F-106 behind a C-141......

The old KellySpace project... :)

http://www.kellyspace.com/launchvehicle/
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Comga on 02/01/2016 04:33 am
IBDM/IDS or whatever it's called, seems to be a pretty expensive piece of kit. On DC, it's expendable. On Dragon, they bring it back.

Does SpaceX reuse the CBM on the Cargo Dragon ?

They probably reuse some internal components, but the exterior is exposed to the re-entry environment, so probably not? In Dragon 2, however, the docking adapter will be hidden behind the nose cone which should make it much easier to reuse.

I think what yg1968 and Nibb31 are saying is that the IBDM/IDS is on the aft end of the cargo module. not the back of the DC, so that it gets disposed of with the cargo module.  No parts will be recoverable.  Is that not correct?

Which got me to thinking.  Has anyone done a comparison of the DC Cargo Module to Dragon?
Is the cargo module actually larger than Dragon?
In some ways they are comparable objects, truncated cones with cargo volumes and solar panels.
The huge differences include that the DC Cargo Module does not need RCS or a reentry gear, but it has releasable docking rings, of one sort or another on both ends AND it has to "carry" the DC on its "nose" thru launch.
It seems like a small part of the Cargo DC plan but a huge task.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: yg1968 on 02/04/2016 05:15 pm
Quote
Sirangelo: planning a 60-day turnaround for Dream Chaser between landing and next launch; enables 4-5 missions/yr with same vehicle.
https://twitter.com/jeff_foust/status/694528522216423424
Where did I see those extremely aggressive turnaround times for a reusable space vehicle during the late 70s / early 80s?

I was actually thinking the opposite. Every two months isn't rapid reusability. If access to space is going to come down in price, reusable LVs and spacecrafts will need to be able to get to space on a weekly basis and eventually on a daily basis (not every two months). Maybe that's why Blue and SpaceX decided to go with a capsule.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: MarkM on 02/04/2016 06:19 pm
Thanks for bring this over to the discussion thread YG1968!

To understand if the 60 day turnaround is reasonable could we not compare it to the workflows that were actually experienced in turning around an orbiter? The DC should take less time as it is smaller(less heat shields to survey and repair)  no SSME's to pull out and replace and no toxic OMS to deal with.

Also re-stacking should also take less time - no large solids and external tank to be mated just one core and some strap-on boosters but to make the comparison consistent perhaps just looking at the time form wheels stop to when the vehicle would be available to be restacked would be a good comparison.

Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Rocket Science on 02/04/2016 06:41 pm
Blue's capsule is sub-orbital so we should set it aside for now for the sake of discussion. Dragon and DC would be a fair comparison. Another thought to consider is that whether or not there is a need for a rapid turnaround based on demand.  I would like to see a refurbished Dragon fly and what time and material costs were involved. The truth will begin to reveal itself when the first Dream Chaser returns and upon post landing inspections...
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Lars-J on 02/04/2016 06:52 pm
The truth will begin to reveal itself when the first Dream Chaser returns and upon post landing inspections...

Exactly... Turnaround time estimates done *before* the first post landing inspections should be taken with a big grain of salt.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: pathfinder_01 on 02/04/2016 06:58 pm
The truth will begin to reveal itself when the first Dream Chaser returns and upon post landing inspections...

Exactly... Turnaround time estimates done *before* the first post landing inspections should be taken with a big grain of salt.

It could be very possible. This thing is orders of magnitude simpler than an shuttle. It's heat shield should be protected during launch and it is unmanned.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: TrevorMonty on 02/04/2016 07:48 pm
The truth will begin to reveal itself when the first Dream Chaser returns and upon post landing inspections...

Exactly... Turnaround time estimates done *before* the first post landing inspections should be taken with a big grain of salt.

It could be very possible. This thing is orders of magnitude simpler than an shuttle. It's heat shield should be protected during launch and it is unmanned.
Turnaround of X37B is a better reference.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Rocket Science on 02/04/2016 08:06 pm
The truth will begin to reveal itself when the first Dream Chaser returns and upon post landing inspections...

Exactly... Turnaround time estimates done *before* the first post landing inspections should be taken with a big grain of salt.

It could be very possible. This thing is orders of magnitude simpler than an shuttle. It's heat shield should be protected during launch and it is unmanned.
Turnaround of X37B is a better reference.
They could tell us, but then they would have to kill us... ;D
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Rocket Science on 02/04/2016 08:13 pm
The truth will begin to reveal itself when the first Dream Chaser returns and upon post landing inspections...

Exactly... Turnaround time estimates done *before* the first post landing inspections should be taken with a big grain of salt.

It could be very possible. This thing is orders of magnitude simpler than an shuttle. It's heat shield should be protected during launch and it is unmanned.
Agree, much simpler machine but with a smaller maintenance crew as well compared to NASA's standing army for the orbiter...
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: rayleighscatter on 02/04/2016 08:18 pm
The truth will begin to reveal itself when the first Dream Chaser returns and upon post landing inspections...

Exactly... Turnaround time estimates done *before* the first post landing inspections should be taken with a big grain of salt.

It could be very possible. This thing is orders of magnitude simpler than an shuttle. It's heat shield should be protected during launch and it is unmanned.

Not to mention the bane of shuttle TPS was the ET foam. But DC isn't launching on a LV with foam, and it isn't launching side mounted.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Lee Jay on 02/04/2016 08:25 pm
The risk to the TPS on DC is MMOD on orbit and impacts from FOD getting kicked up by the landing gear (and skid) on landing.  Much lower risk than Shuttle, but not zero.  The TPS is also designed from lessons learned on Shuttle to make it much easier to repair, and the leading edge material isn't RCC.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Star One on 02/04/2016 09:19 pm
The truth will begin to reveal itself when the first Dream Chaser returns and upon post landing inspections...

Exactly... Turnaround time estimates done *before* the first post landing inspections should be taken with a big grain of salt.

It could be very possible. This thing is orders of magnitude simpler than an shuttle. It's heat shield should be protected during launch and it is unmanned.
Turnaround of X37B is a better reference.

Does the X37B now even exist as we never saw any pictures of it before launch last time.;)
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Rocket Science on 02/04/2016 10:06 pm
Not having to deal with a vehicle that has hypergolics on board or residue aids in streamlining the turn around time as well...
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: adrianwyard on 02/04/2016 10:47 pm
Can I suggest the more important turnaround metric for DC (and other reusable spacecraft) is net cost (that's related to complexity of maintenance tasks) rather than time? What are the chances that during DC's lifetime it's next launch will be delayed because everything's raring to go apart from DC itself?

And here's where things like non-toxic propellants win big: in terms of lower complexity and cost of maintenance.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Rocket Science on 02/05/2016 01:02 pm
I posted this is the update thread as well. So we have seen The "twin screen" cockpit which appears to be able to switch modes from orbit to atmospheric flight display (as seen in my previous NASA sim photo).

Dream Chaser prototype cockpit 2015.

http://vri.vlaanderen/nl/ruimtevaartdagen-2015/eyecatchers/
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: adrianwyard on 02/05/2016 01:52 pm
Google translated:

Quote
Another attraction of the exhibition is the prototype of the Dream Chaser shuttle cockpit (Scale 1: 1). The cockpit is equipped with active steering controls and displays. An external projection system creates the area observed by the crew [...] docks to the space station. Visitors can take the opportunity to sit in the Dream Chaser and also to control it through the simplified flight simulator
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: abaddon on 02/05/2016 02:04 pm
Not having to deal with a vehicle that has hypergolics on board or residue aids in streamlining the turn around time as well...
This issue is hugely overblown.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: yg1968 on 02/05/2016 02:14 pm
Not having to deal with a vehicle that has hypergolics on board or residue aids in streamlining the turn around time as well...
This issue is hugely overblown.

It's likely not overblown if your landing at a regular airport. But DC is going to land at KSC where this shouldn't be an issue anyways.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: yg1968 on 02/05/2016 02:16 pm
Very good interview with John Roth of SNC on DC:
http://observer.com/2016/02/nasas-new-space-shuttle-is-a-work-of-futuristic-art/

This part of the interview on crewed DC is interesting:

Quote
Will SNC compete for the next round of commercial crew contracts that NASA is expected to award in 2020?

That is certainly on our radar scope, yes. That is something we are very interested in doing. We do need to try and find the best route in working on the crew version. First, it’s going to take some investment funding and that could be either internal, external, or a combination. The second thing is that we absolutely want to make sure we are successful on the cargo missions. So we’ve got to make sure the resources are directed towards making that cargo design and getting that vehicle built.

Whether we can actually go after that contract or not when it gets to that point, is going to be matter of whether we can get the right resources to get there.

In other words, there won't be a crewed version of DC unless they get outside investors to help with the funding for it. Hopefully, this is where Paul Allen might come in.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: JasonAW3 on 02/05/2016 02:19 pm
The truth will begin to reveal itself when the first Dream Chaser returns and upon post landing inspections...

Exactly... Turnaround time estimates done *before* the first post landing inspections should be taken with a big grain of salt.

It could be very possible. This thing is orders of magnitude simpler than an shuttle. It's heat shield should be protected during launch and it is unmanned.

Not to mention the bane of shuttle TPS was the ET foam. But DC isn't launching on a LV with foam, and it isn't launching side mounted.

The one TPS issue that MIGHT have been an issue if the Shuttle had have been top mounted instead of side mounted, would have been bird strikes.  That shouldn't have been much of an issue as any bird strikes would have been at a low enough altitude and velocity that damage should have been minimal, if any.

     The sad thing about the Shuttle is; today, we can make far more robust TPS systems, including carbon-carbon leading edges, than we could during the Shuttle program, due to vastly improved materials manufacturing techniques, many of which, likely descended from lessons learned from Shuttle operations.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: JasonAW3 on 02/05/2016 02:23 pm
Not having to deal with a vehicle that has hypergolics on board or residue aids in streamlining the turn around time as well...
This issue is hugely overblown.

It's likely not overblown if your landing at a regular airport. But DC is going to land at KSC where this shouldn't be an issue anyways.

For Nasa payloads.

     It is entirely possible that the DC will land at commercial spaceports, and eventually, airports, to accommodate commercial launches.  Obviously, at first, it will land at Kennedy, or possibly Nellis, or White Sands, depending on mission requirements, but if it is as flexible as it appears, other landing sites will become available as needed.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: yg1968 on 02/05/2016 02:27 pm
For CRS2 missions, DC will land at the Shuttle landing site:

Quote
What are the plans for launch and landing sites? Will the Kennedy Space Center play a major role?

The contract right now for the cargo missions is based on launches out of Kennedy and landing at the shuttle landing site facility at Kennedy. Obviously we’d have an option—if they wanted—to discuss with us launching and landing from somewhere else but that’s our baseline concept in the CRS2 proposal. We have been working with a lot of different airports and spaceports both in the US and internationally who are interested in being able to land Dream Chaser at their facilities. We have had a number of discussions with those airports and spaceports. We have a few that are public like Houston and Alabama and a few others that we have been working with that have elected not to go public yet.

We are moving forward towards plans to look at eventual FAA licensing for landing Dream Chaser at other places than Kennedy. That right now is not part of our cargo contract.

http://observer.com/2016/02/nasas-new-space-shuttle-is-a-work-of-futuristic-art/
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: adrianwyard on 02/05/2016 02:36 pm
'Overblown' is a relative term. If the vehicle does not have toxic hypergolics then readying it for launch, and servicing for reflight is all but guaranteed to be safer and less costly than if the vehicle does, right?

Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: yg1968 on 02/05/2016 02:38 pm
This part of the interview is also interesting:

Quote
Was there a shift in vision for SNC in terms of moving from crew transportation to cargo? [...]

It wasn’t as easy as simply looking at the crew vehicle and saying, “OK we’re going to pull seats, pull out people and stick in cargo.”  It would not have been a good vehicle for the cargo program. It would not have been competitive. We had to go through an incredible redesign process to come up with the idea of the cargo module and to come up with a way to make room for additional cargo.

Taking out the abort engines for example which we don’t need for cargo. We needed to fit inside a fairing so we had to come up with a redesign for the wings to be able to fold. There was about a dozen major things that we had to address to see if we could really make this crew vehicle to what we thought would be an exceptional cargo vehicle.

http://observer.com/2016/02/nasas-new-space-shuttle-is-a-work-of-futuristic-art/
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Rocket Science on 02/05/2016 02:43 pm
Not having to deal with a vehicle that has hypergolics on board or residue aids in streamlining the turn around time as well...
This issue is hugely overblown.
Oh really?? ???

http://www.ilpi.com/msds/ref/hypergolic.html
http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/20100038321.pdf
http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/20100042352.pdf

https://www.youtube.com/watch?v=QN8kjvlePBw
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: dror on 02/05/2016 02:55 pm
Does the crew DC use it's own rockets in a nominal flight?
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: abaddon on 02/05/2016 03:06 pm
The sad thing about the Shuttle is; today, we can make far more robust TPS systems, including carbon-carbon leading edges, than we could during the Shuttle program, due to vastly improved materials manufacturing techniques, many of which, likely descended from lessons learned from Shuttle operations.
This is off-topic, but why is that a sad thing?  That is a tangible legacy of Shuttle.

Back on topic, the Shuttle is only very slightly a better comparison to DC as it is to F9 first stages and Dragon capsules, which is to say, it is a terrible comparison.  Rapid turnaround time of DC is likely more of a cost and flight history issue than a capabilities issue, in my opinion.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: yg1968 on 02/05/2016 04:11 pm
Does the crew DC use it's own rockets in a nominal flight?

In SNC's CGI video, crewed DC uses its two main engines. But in real life, I don't know.

See the image in this post:
http://forum.nasaspaceflight.com/index.php?topic=29417.msg1482736#msg1482736
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: TrevorMonty on 02/05/2016 04:50 pm
http://observer.com/2016/02/nasas-new-space-shuttle-is-a-work-of-futuristic-art/

The history stems from the BOR-4, a subscale test version of a manned spaceplane that the Soviets experimented with (some orbital launches and sub-orbital launches) back in the 1980s. 


The DC selection should have made a few BOR-4 engineers in Russia and NASA HL20 engineers happy. Nice to see all their hard work was not in vain and will eventually fly to space.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Rocket Science on 02/18/2016 12:28 am
I found a great photo from the early lifting body days with a model that looks a lot like Dream Chaser's frontal view on the desk (minus the cockpit detail) interesting... ;)

Alphonso Stewart, left; Ken Iliff, center; and Dale Reed, right; were part of the center's lifting body aircraft study group.

http://www.nasa.gov/image-feature/defining-the-future
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Jim on 02/18/2016 02:09 am
'Overblown' is a relative term. If the vehicle does not have toxic hypergolics then readying it for launch, and servicing for reflight is all but guaranteed to be safer and less costly than if the vehicle does, right?



the costs are not that big.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: RanulfC on 02/18/2016 05:49 pm
I found a great photo from the early lifting body days with a model that looks a lot like Dream Chaser's frontal view on the desk (minus the cockpit detail) interesting... ;)

Alphonso Stewart, left; Ken Iliff, center; and Dale Reed, right; were part of the center's lifting body aircraft study group.

http://www.nasa.gov/image-feature/defining-the-future

The frontal view is of (IIRC) the GE Lenticular Reentry Vehicle concept which was supposed to "fix" certain design flaws of the original Kehlet design. ("" because the design not only didn't fix anything it was all around the worst possible design choices for a lenticular vehicle :) )

Always wished someone had flown a test version of the LRVs :)

Randy
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Rocket Science on 02/18/2016 10:36 pm
I found a great photo from the early lifting body days with a model that looks a lot like Dream Chaser's frontal view on the desk (minus the cockpit detail) interesting... ;)

Alphonso Stewart, left; Ken Iliff, center; and Dale Reed, right; were part of the center's lifting body aircraft study group.

http://www.nasa.gov/image-feature/defining-the-future

The frontal view is of (IIRC) the GE Lenticular Reentry Vehicle concept which was supposed to "fix" certain design flaws of the original Kehlet design. ("" because the design not only didn't fix anything it was all around the worst possible design choices for a lenticular vehicle :) )

Always wished someone had flown a test version of the LRVs :)

Randy
I agree Randy that it appears to be from that family of vehicles, if not GE's,  at least the less radical of the proposals. Here are some from Langley "in family" of low camber "flat bottom rounded top" from low speed testing...
~Rob

(I should put these in my Lifting Body Q&A thread)

http://crgis.ndc.nasa.gov/historic/12-Foot_Low_Speed_Tunnel_Models_N-Z
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Rocket Science on 02/18/2016 11:01 pm
This was Martin''s evolution:

Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: rayleighscatter on 03/10/2016 08:53 pm
From an article posted on the UPDATE side: http://forum.nasaspaceflight.com/index.php?topic=29416.msg1502495#msg1502495

Quote
“We’re about to fly the entry test article again here at the end of this year or the first quarter of next year [2015-2016]. It’s ready to ship, we’re going to ship the engineering test article back out to Edwards Air Force Base in October.
Which makes it look like at least part of this interview was probably last year but it should be interesting to see how quickly we may see the next test flight. I'm not neccisarily holding out hope for what's left of Q1 (especially since the CRS announcement had slipped from September to January) but hopefully by this summer we'll have seen DC free flying again.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: TrevorMonty on 03/11/2016 05:33 am
I found a great photo from the early lifting body days with a model that looks a lot like Dream Chaser's frontal view on the desk (minus the cockpit detail) interesting... ;)

Alphonso Stewart, left; Ken Iliff, center; and Dale Reed, right; were part of the center's lifting body aircraft study group.

http://www.nasa.gov/image-feature/defining-the-future

The frontal view is of (IIRC) the GE Lenticular Reentry Vehicle concept which was supposed to "fix" certain design flaws of the original Kehlet design. ("" because the design not only didn't fix anything it was all around the worst possible design choices for a lenticular vehicle :) )

Always wished someone had flown a test version of the LRVs :)

Randy
I agree Randy that it appears to be from that family of vehicles, if not GE's,  at least the less radical of the proposals. Here are some from Langley "in family" of low camber "flat bottom rounded top" from low speed testing...
~Rob

(I should put these in my Lifting Body Q&A thread)

http://crgis.ndc.nasa.gov/historic/12-Foot_Low_Speed_Tunnel_Models_N-Z
Thunderbirds are go!
Always thought No2 was cool.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Mike Harris-Stone on 03/12/2016 01:07 am
I'm pretty sure my Dad mentioned Dale Reed in connection with work on the HL-20. 

I googled and found this book written by Dale with a forward by Chuck Yeager.   8)

It chronicles NASA's lifting body research including the HL-20 which of course became the DC.  (And also discusses the BOR4)

https://books.google.com/books?id=btAeBgAAQBAJ&pg=PA181&lpg=PA181&dq=dale+reed+hl-20&source=bl&ots=mGHlXrc90C&sig=BgBYg78qHPmyvwTtYXGR-gplauk&hl=en&sa=X&ved=0ahUKEwi2nZyyhrrLAhVB7CYKHWsDASEQ6AEILjAD (https://books.google.com/books?id=btAeBgAAQBAJ&pg=PA181&lpg=PA181&dq=dale+reed+hl-20&source=bl&ots=mGHlXrc90C&sig=BgBYg78qHPmyvwTtYXGR-gplauk&hl=en&sa=X&ved=0ahUKEwi2nZyyhrrLAhVB7CYKHWsDASEQ6AEILjAD)

Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: yg1968 on 03/12/2016 01:41 am
This book is also available online here:

http://history.nasa.gov/SP-4220/contents.htm
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: lucspace on 03/13/2016 05:17 pm
I have managed to get confused about the original Dream Chaser and Dream Chaser Cargo System. As I understand, the cargo system would feature a reduced scale spaceplane. But in the recent new cgi's from SNC, I have the impression the unmanned vehicle is just as large as the manned version would be... Am I wrong?
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: lucspace on 03/13/2016 05:22 pm
Also, this SNC image of the cargo version suddenly features a nose wheel... artist's mistake or something we don't know about?

http://mediakit.sncorp.com/mediastore/image/UDC_Cargo%20Unload_Runway_0222_5.jpg
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: okan170 on 03/13/2016 05:42 pm
Also, this SNC image of the cargo version suddenly features a nose wheel... artist's mistake or something we don't know about?

http://mediakit.sncorp.com/mediastore/image/UDC_Cargo%20Unload_Runway_0222_5.jpg

I think its a trick of perspective there, we're seeing the far rear wheel and the forward skid looks a bit like a door for it hanging open, but theres no third wheel in the front.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: rayleighscatter on 03/13/2016 07:22 pm
I have managed to get confused about the original Dream Chaser and Dream Chaser Cargo System. As I understand, the cargo system would feature a reduced scale spaceplane. But in the recent new cgi's from SNC, I have the impression the unmanned vehicle is just as large as the manned version would be... Am I wrong?
The crew and cargo DCs are the same size.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: lucspace on 03/13/2016 08:50 pm
Thanks! Now realise I was confused with the Stratolaunch version, which was intended to be scaled down.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: adrianwyard on 03/13/2016 09:12 pm
Let's hope it's a trick of perspective because if not, and this graphic is correct, then Cargo Dream Chaser has no right main landing gear, just a door.

And we know that doesn't work well because they've flight tested that configuration...😉
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Rocket Science on 03/14/2016 12:38 am
Let's hope it's a trick of perspective because if not, and this graphic is correct, then Cargo Dream Chaser has no right main landing gear, just a door.

And we know that doesn't work well because they've flight tested that configuration...😉
Aw, she can take it... ;D
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: JAFO on 03/14/2016 05:06 am
Let's hope it's a trick of perspective because if not, and this graphic is correct, then Cargo Dream Chaser has no right main landing gear, just a door.

And we know that doesn't work well because they've flight tested that configuration...😉
Aw, she can take it... ;D

Remember: A Good landing is one you can walk away from. A GREAT landing is one where you can use the vehicle again right away.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Rocket Science on 03/14/2016 07:46 am
Let's hope it's a trick of perspective because if not, and this graphic is correct, then Cargo Dream Chaser has no right main landing gear, just a door.

And we know that doesn't work well because they've flight tested that configuration...😉
Aw, she can take it... ;D

Remember: A Good landing is one you can walk away from. A GREAT landing is one where you can use the vehicle again right away.
Yes, but I've never to yet seen a spacecraft "ever" being re-flown "right away" either... ;)
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: yg1968 on 03/24/2016 11:01 pm
SNC Space store:

http://www.snclogoshop.com/ecommerce/
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Alpha Control on 03/25/2016 12:10 am
SNC Space store:

http://www.snclogoshop.com/ecommerce/

Thanks YG! Some nice items. But what I really want is the Dream Chaser model the lady wearing the polo is holding!
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: JAFO on 03/25/2016 12:15 am
Sorry if this has been answered, but why did SNC go with folding wings for  the cargo version? Was there a problem with the aerodynamics of an unfaired vehicle?


TIA
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: ethan829 on 03/25/2016 12:47 am
Sorry if this has been answered, but why did SNC go with folding wings for  the cargo version? Was there a problem with the aerodynamics of an unfaired vehicle?


Flying inside a standard 5-meter fairing makes integration with the launch vehicle much simpler. I also don't know how they would have accommodated the unpressurized cargo module without a fairing.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: brickmack on 04/04/2016 04:01 pm
I also don't know how they would have accommodated the unpressurized cargo module without a fairing.

Probably would have looked rather like Hermes (http://www.esa.int/var/esa/storage/images/esa_multimedia/images/2009/12/ariane_5_in_hermes_configuration_1991/9657602-3-eng-GB/Ariane_5_in_Hermes_configuration_1991.jpg ). Put any unpressurized cargo lower down towards the base of the pressurized expendable compartment, covered up by sort of an interstage-like structure
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Citabria on 04/06/2016 02:56 pm
Also, this SNC image of the cargo version suddenly features a nose wheel... artist's mistake or something we don't know about?

http://mediakit.sncorp.com/mediastore/image/UDC_Cargo%20Unload_Runway_0222_5.jpg

I think its a trick of perspective there, we're seeing the far rear wheel and the forward skid looks a bit like a door for it hanging open, but theres no third wheel in the front.

If the gear doesn't come down, then DC could just yaw right and ditch! ;)
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Alpha Control on 04/07/2016 07:31 pm
Article from the Alabama dot com site, from 3/31:
"Dream Chaser spaceship seems on a glide path to landing in Alabama".

The Huntsville Chamber of Commerce "...held a workshop in Huntsville on the space marketplace of tomorrow that drew 70 people from business, government and academia."

http://www.al.com/news/huntsville/index.ssf/2016/03/will_huntsville_be_a_spaceport.html

SNC notes that caught my eye:

"Right now, Huntsville is the only community we're moving forward with a (landing) license on."

"the company 'is trying to develop a commercial base' for Dream Chaser beyond supplying the space station."

Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: okan170 on 04/16/2016 06:55 pm
SNC Space store:

http://www.snclogoshop.com/ecommerce/

DC cargo mug came today.  Printing could be better, but it's kind of worth it to have a mug with a cargo spaceplane on it!

Later Edit:
The DC mug may not be suitable for long term tea or beverage use, the interior printing has started to loosen after a few thermal cycles and I've now repurposed it for a desk top pen holder.  (Block 2 of the mug should address this, and add a bit of orange that only shows up when you pour hot water into the cup ;) )
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: yg1968 on 06/06/2016 02:04 pm
Commercial missions planned for 2020-2021 will carry experiments arranged by NanoRacks

See more at: http://www.parabolicarc.com/2016/06/03/nsrc-day-2-summary/#more-58577

Hmm, commercial missions. Will SNC succeed with commercial DC missions when SpaceX has failed with its DragonLab?
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: rayleighscatter on 06/06/2016 09:57 pm
Commercial missions planned for 2020-2021 will carry experiments arranged by NanoRacks

See more at: http://www.parabolicarc.com/2016/06/03/nsrc-day-2-summary/#more-58577

Hmm, commercial missions. Will SNC succeed with commercial DC missions when SpaceX has failed with its DragonLab?

I wonder if those lower re-entry G's are more of a selling point than people gave it credit for.

I also wonder if there's any way to clarify whether those commercials missions will be independent missions or will they be hitchhiking on a CRS flight?
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: yg1968 on 06/07/2016 12:20 am
Doug Messier says that he thinks so (he is pretty sure):

https://twitter.com/spacecom/status/739973583837921280

Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Robotbeat on 06/07/2016 12:40 am
I'm not convinced.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Patchouli on 06/17/2016 11:13 pm
Commercial missions planned for 2020-2021 will carry experiments arranged by NanoRacks

See more at: http://www.parabolicarc.com/2016/06/03/nsrc-day-2-summary/#more-58577

Hmm, commercial missions. Will SNC succeed with commercial DC missions when SpaceX has failed with its DragonLab?

I wonder if those lower re-entry G's are more of a selling point than people gave it credit for.

I also wonder if there's any way to clarify whether those commercials missions will be independent missions or will they be hitchhiking on a CRS flight?
It also allows quicker access to the experiments then DragonLab after landing.
There is no waiting several hours to recover your experiments all the time they're being exposed to Earth conditions and possibly salt water.
I wonder if the latter is what has been holding DragonLab back as potential researchers are waiting for powered landings to be an option.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Rocket Science on 07/29/2016 04:53 pm
I was looking at the photos of DC in the update thread and I noticed that she is fitted with pitot tubes and other air data inlets leading me to think that the "may" fly her without the pitch/yaw air data flight test boom on her nose...
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Ben the Space Brit on 08/05/2016 09:37 am
Random thought:
The DC looks like the space plane from 'A Spaceman in King Arthur's Court'. This might not be coincidental because I believe the model and full-scale prop were based on the same NASA lifting body that is the ancestor of the DC (The HL-20, IIRC).
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: rpapo on 08/05/2016 10:35 am
From the update thread:
Will the dream chaser missions be piloted or non-piloted flights?
Non crewed for Cargo. But having the Cargo version flying will retire a lot of risk for a crewed version.
In nearly the same way as has happened with Dragon.  They get practice with how to build and operate the thing.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: manboy on 08/06/2016 06:09 pm
Is SNC building the cargo module or is it some outside contractor?
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: yg1968 on 08/29/2016 09:20 pm
Is SNC building the cargo module or is it some outside contractor?

Likely both. Like Orbital/ATK, SNC subcontracts a lot. But it seems to me that the cargo module has some similarity with the rest of their operations.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: BrightLight on 09/13/2016 05:53 pm
A video from MSNBC aired on August 30 - has some interesting views of the DC crew mockup

http://video.cnbc.com/gallery/?video=3000547012
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Rocket Science on 12/20/2016 11:18 am
Is there a possibility that we could send a NSF member representative to be on hand and behind the scenes for the upcoming ALT. I would be willing to chip in for expenses if others are willing to help cover as well. Perhaps Chris you might be able to approach SNC to help make this happen? :)
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: yg1968 on 12/29/2016 08:39 pm
I have been wondering about the crewed DC's abort system. There isn't much detail on it but this 2014 press release seems to provide the most detailed information on it:

Quote from: SNC
The Dream Chaser MPS [Main Propulsion System] will not only power the spacecraft in orbit, it also offers a unique abort capability while on the launch pad and throughout the flight trajectory, unlike human space transportation capsules. The MPS technology used on the Dream Chaser results in a safe runway landing during an abort scenario, further reducing risk to the crew, spacecraft and payload.

http://www.sncorp.com/news-resources/2014/snc-dc-propulsion_7-8-14.html


 
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: whitelancer64 on 12/29/2016 08:52 pm
I have been wondering about the crewed DC's abort system. There isn't much detail on it but this 2014 press release seems to provide the most detailed information on it:

Quote from: SNC
The Dream Chaser MPS [Main Propulsion System] will not only power the spacecraft in orbit, it also offers a unique abort capability while on the launch pad and throughout the flight trajectory, unlike human space transportation capsules. The MPS technology used on the Dream Chaser results in a safe runway landing during an abort scenario, further reducing risk to the crew, spacecraft and payload.

http://www.sncorp.com/news-resources/2014/snc-dc-propulsion_7-8-14.html

What you read is what you get. Fire main engines to abort to the Shuttle runway. In flight, basically the Shuttle abort options, either flip around back to KSC or land downrange. IIRC it's supposed to be able to float in case of a water landing, but that's not what it's designed for.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: yg1968 on 12/29/2016 09:26 pm
I am not an engineer but isn't it a better system than the Shuttle in the sense that the abort motor can help DC escape the rocket by going faster than it? The fact that DC is on top of the rocket probably also gives it a head start.

The press release makes it sound like it could abort to a runway all the way through ascent.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Rocket Science on 12/29/2016 09:55 pm
I am not an engineer but isn't it a better system than the Shuttle in the sense that the abort motor can help DC escape the rocket by going faster than it? The fact that DC is on top of the rocket probably also gives it a head start.

The press release makes it sound like it could abort to a runway all the way through ascent.
Correct yg, here are the preferred landing sites during abort:
http://www.americaspace.com/?p=86264
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Rocket Science on 12/29/2016 10:03 pm
Thanks! Where does that slide come from?
Just posted it above! ;)
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: yg1968 on 12/29/2016 10:19 pm
I found this 2016 SNC presentation which details the type of engines that SNC does (slide 5):

http://www.icao.int/Meetings/SPACE2016/Presentations/1%20-%20M.%20Sirangelo%20-%20SNC.pdf
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Rocket Science on 12/30/2016 04:03 pm
What I don't see are any engines "specifically" for a Crewed DC variant for use as abort engines or MPS assuming there are getting rid of the hybrid motors. They do have a wider range of engines and propellants with ORBITEC in the SNC family now...
http://www.sncspace.com/AboutUs/NewsDetails/2243
http://www.spaceflightinider.com/missions/commercial/snc-orbitec-completes-testing-of-rocket-propellants/
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: TrevorMonty on 12/30/2016 05:34 pm
What I don't see are any engines "specifically" for a Crewed DC variant for use as abort engines or MPS assuming there are getting rid of the hybrid motors. They do have a wider range of engines and propellants with ORBITEC in the SNC family now...
http://www.sncspace.com/AboutUs/NewsDetails/2243
http://www.spaceflightinider.com/missions/commercial/snc-orbitec-completes-testing-of-rocket-propellants/
The abort engines or lack of proven ones wouldn't of help during CC down select process.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Rocket Science on 12/31/2016 01:20 am
What I don't see are any engines "specifically" for a Crewed DC variant for use as abort engines or MPS assuming there are getting rid of the hybrid motors. They do have a wider range of engines and propellants with ORBITEC in the SNC family now...
http://www.sncspace.com/AboutUs/NewsDetails/2243
http://www.spaceflightinider.com/missions/commercial/snc-orbitec-completes-testing-of-rocket-propellants/
The abort engines or lack of proven ones wouldn't of help during CC down select process.
We don't really know what a future variant of a Crewed DC would utilize...
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: yg1968 on 01/03/2017 09:15 pm
In my opinion, the news below means that crewed DC is pretty much dead. 

Mission Awards Secure Commercial Crew Transportation for Coming Years:
https://www.nasa.gov/feature/mission-awards-secure-commercial-crew-transportation-for-coming-years

Both SpaceX and Boeing get 4 more post-certification missions each which means that NASA is set for commercial crew until 2024.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: RonM on 01/04/2017 12:43 am
In my opinion, the news below means that crewed DC is pretty much dead. 

Mission Awards Secure Commercial Crew Transportation for Coming Years:
https://www.nasa.gov/feature/mission-awards-secure-commercial-crew-transportation-for-coming-years

Both SpaceX and Boeing get 4 more post-certification missions each which means that NASA is set for commercial crew until 2024.

Well, I think we already knew that as far as NASA is concerned. The question is can crewed DC get any other customers?
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: TrevorMonty on 01/04/2017 07:52 am
The cargo DC could be used as mini station with crew visiting it on regular basis. Use crew vehicle ECLSS, bathroom and kitchen facility, while DC provides lab and extra living space. All the consumerables and waste are kept in crew vehicle which returns to earth.

The DC can return to earth every so often (5-10 missions) for refurbishment.

There is also bonus safety feature, if anything happens to crew vehicle, the crew can return in DC.

Just another thought on this. The additional modules can still stay in space instead of being disposed of when DC return. Either add station keeping module (Cygnus) or have replacement DC take over before original DC returns.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Rocket Science on 01/04/2017 08:29 am
With respect to the last few posts on the update thread which should be best made here on the discussion thread:
We don't know the life extension of the ISS as mentioned nor do we know Bigelow's plans. Orbital tourism flights are still another unknown. Commercial space means NASA isn't the only game in town anymore... The Cargo DC gets them 80% there toward a crew variant and the rest can still up to Mark's personal wish to fly to space in it. He can still launch it at a much reduced cost on Falcon as opposed to Atlas. So I guess we'll wait and see while looking forward to the ALT... Hey, that rhymes! ;D
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: adrianwyard on 01/04/2017 08:35 am
It's a neat idea. If the UN crewed DC mission actually happens, this would be an easy way to enhance its capabilities. i.e. it would provide volume for countries to conduct very high quality long duration microgravity experiments, with occasional human maintenance and low-g return. I wonder if that's a capability that can be sold to others separately?

I've no idea if the UN thing will happen, however. And if we assume the development and test of abort motors/capability is required for crewed DC, then that is a big ticket item that has to be paid for by someone.

Or, if cargo DC proves successful and reliable, I wonder if SNC would consider adding ECLSS to it one day and trusting the launch vehicle to not fail... That would at least be consistent with its winged predecessor. :-)
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: yg1968 on 01/04/2017 02:33 pm
In my opinion, the news below means that crewed DC is pretty much dead. 

Mission Awards Secure Commercial Crew Transportation for Coming Years:
https://www.nasa.gov/feature/mission-awards-secure-commercial-crew-transportation-for-coming-years

Both SpaceX and Boeing get 4 more post-certification missions each which means that NASA is set for commercial crew until 2024.

Well, I think we already knew that as far as NASA is concerned. The question is can crewed DC get any other customers?

These new missions were optional. NASA could have decided not to exercise them. SNC was hoping that NASA would have a new competition for these new missions. However, it is still possible that NASA will buy more commercial crew missions for the 2024 to 2028 period. 

The maximum amount of post-certification missions is six (see link below for more on this). NASA will have to create a new round for the years 2024-2028 if the ISS is extended to 2028. So SNC may have a chance if ISS is extended until that time.

http://forum.nasaspaceflight.com/index.php?topic=32412.msg1257904#msg1257904

Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: yg1968 on 01/04/2017 02:36 pm
It's a neat idea. If the UN crewed DC mission actually happens, this would be an easy way to enhance its capabilities. i.e. it would provide volume for countries to conduct very high quality long duration microgravity experiments, with occasional human maintenance and low-g return. I wonder if that's a capability that can be sold to others separately?

I've no idea if the UN thing will happen, however. And if we assume the development and test of abort motors/capability is required for crewed DC, then that is a big ticket item that has to be paid for by someone.

Or, if cargo DC proves successful and reliable, I wonder if SNC would consider adding ECLSS to it one day and trusting the launch vehicle to not fail... That would at least be consistent with its winged predecessor. :-)

I was thinking that. Once CRS2 is over, perhaps SNC could upgrade one of its two cargo DC for crew. I don't know how feasible that would be.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Rocket Science on 01/04/2017 02:53 pm
It's a neat idea. If the UN crewed DC mission actually happens, this would be an easy way to enhance its capabilities. i.e. it would provide volume for countries to conduct very high quality long duration microgravity experiments, with occasional human maintenance and low-g return. I wonder if that's a capability that can be sold to others separately?

I've no idea if the UN thing will happen, however. And if we assume the development and test of abort motors/capability is required for crewed DC, then that is a big ticket item that has to be paid for by someone.

Or, if cargo DC proves successful and reliable, I wonder if SNC would consider adding ECLSS to it one day and trusting the launch vehicle to not fail... That would at least be consistent with its winged predecessor. :-)

I was thinking that. Once CRS2 is over, perhaps SNC could upgrade one of its two cargo DC for crew. I don't how feasible that would be.
Did we ever get a handle-on how many orbital pressure vessels are to be constructed? I don't recall it at the moment...
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: yg1968 on 01/04/2017 03:05 pm
Yes, two spacecrafts.

http://forum.nasaspaceflight.com/index.php?topic=29416.msg1476914#msg1476914
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Rocket Science on 01/04/2017 03:12 pm
Yes, two spacecrafts.

http://forum.nasaspaceflight.com/index.php?topic=29416.msg1476914#msg1476914
Thanks yg, so no "third" incomplete bare hull as far as I can see at this point...
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: baldusi on 01/06/2017 01:22 am
When Cargo DC is flying, and Spacex and Boeing have ironed out the kinks of crew rating, SNC can have a "simple" path to crew.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Robotbeat on 01/06/2017 03:05 am
When Cargo DC is flying, and Spacex and Boeing have ironed out the kinks of crew rating, SNC can have a "simple" path to crew.
I'd argue the path would be /less/ simple than SpaceX's initial Dragon to Dragon 2.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: vt_hokie on 01/06/2017 06:44 pm
When Cargo DC is flying, and Spacex and Boeing have ironed out the kinks of crew rating, SNC can have a "simple" path to crew.
I'd argue the path would be /less/ simple than SpaceX's initial Dragon to Dragon 2.

Agree.  Making it into an X-38/ACRV type crew return vehicle would probably be relatively simple, but it's the complications for crew launch that would require the most work.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Patchouli on 01/08/2017 12:35 am
]I'd argue the path would be /less/ simple than SpaceX's initial Dragon to Dragon 2.

Well yes and no since it could would allow them to get the life support and EDL ironed out before the abort system is done.



Agree.  Making it into an X-38/ACRV type crew return vehicle would probably be relatively simple, but it's the complications for crew launch that would require the most work.

It would good way to get the capability of the X-38 back at a fraction of the cost of resurrecting the old program.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: baldusi on 01/09/2017 12:54 am
When Cargo DC is flying, and Spacex and Boeing have ironed out the kinks of crew rating, SNC can have a "simple" path to crew.
I'd argue the path would be /less/ simple than SpaceX's initial Dragon to Dragon 2.
DC started as a crew rated vehicle and now is being scoped down as a cargo only. I don't see why it will make it more difficult than Dragon Cargo -> Dragon 2 Crew. And the path to certification will be much clearer with Dragon v2 and CST-100 done.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Robotbeat on 01/09/2017 03:58 am
When Cargo DC is flying, and Spacex and Boeing have ironed out the kinks of crew rating, SNC can have a "simple" path to crew.
I'd argue the path would be /less/ simple than SpaceX's initial Dragon to Dragon 2.
DC started as a crew rated vehicle and now is being scoped down as a cargo only. I don't see why it will make it more difficult than Dragon Cargo -> Dragon 2 Crew. And the path to certification will be much clearer with Dragon v2 and CST-100 done.
Dragon also started as a crew rated vehicle... Remember, they were just going to use a tractor escape tower at first.

The abort system for DC is... HIGHLY non-trivial.

And remember that DC will be launching inside a fairing for cargo, just so they can avoid aero on the way up. That will not work for crewed DC. That right there is a big reason it'll be different.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Steven Pietrobon on 01/09/2017 08:32 am
And remember that DC will be launching inside a fairing for cargo, just so they can avoid aero on the way up. That will not work for crewed DC. That right there is a big reason it'll be different.

I've been thinking that it might be possible to also launch crewed DC in a fairing. Abort is performed with the fairing in place. Abort motors can be added to the base and grid fins added to the sides of the fairing to stabilise it. For attitude control, the abort motors could have steerable nozzles or perhaps use gas injection, like the old Titan solids and PSLV first stage. A hatch on the side would allow crew access.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: sdsds on 01/09/2017 10:05 am
I've been thinking that it might be possible to also launch crewed DC in a fairing. Abort is performed with the fairing in place.

You are describing something like what Soyuz does for pad aborts, right?
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: baldusi on 01/09/2017 02:19 pm
I've been thinking that it might be possible to also launch crewed DC in a fairing. Abort is performed with the fairing in place.

You are describing something like what Soyuz does for pad aborts, right?
Soyuz abort disposes the faring until fairing release. So it does have it until somewhere in the third stage burn. Not optimal, but doable.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Rocket Science on 01/09/2017 02:41 pm
We talked about a crewed DC with a shroud a year back to remind everyone..
http://forum.nasaspaceflight.com/index.php?topic=29417.1560
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Patchouli on 01/09/2017 04:56 pm
And remember that DC will be launching inside a fairing for cargo, just so they can avoid aero on the way up. That will not work for crewed DC. That right there is a big reason it'll be different.

I've been thinking that it might be possible to also launch crewed DC in a fairing. Abort is performed with the fairing in place. Abort motors can be added to the base and grid fins added to the sides of the fairing to stabilise it. For attitude control, the abort motors could have steerable nozzles or perhaps use gas injection, like the old Titan solids and PSLV first stage. A hatch on the side would allow crew access.

Might be possible to keep it strait have grid fins at the base like Soyuz.
The fairing would have to be much heavier to handle to loads and if a tractor abort tower is used it would need to be completely different.

The tricky part would be getting separation done and unfolding the wings for landing before hitting the ground or just accept the mass penalty and carry a parachute.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Robotbeat on 01/09/2017 05:01 pm
Okay, y'all stop making my point for me! :D

Which is: I doubt the transition from cargo DC to crew DC would be any less than from cargo Dragon to crew Dragon.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Rocket Science on 01/09/2017 05:14 pm
I don't believe that anyone considered a crewed "no-shroud hybrid version" of the original DC with separate solid abort motors on the adapter like the HL-20 with the cargo DC's folding wings. For a pad abort: fire the motors to altitude while wings are being extended then a glide to the SLF or Skid Strip...
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: yg1968 on 01/09/2017 05:26 pm
Okay, y'all stop making my point for me! :D

Which is: I doubt the transition from cargo DC to crew DC would be any less than from cargo Dragon to crew Dragon.

I am not sure you compare these two situations. Except for the upcoming drop test, SNC will not be getting any more commercial crew funding from NASA whereas SpaceX will.

Dragon2 is very different from Dragon1. But had SpaceX not received commercial crew funding from NASA, they likely could have saved money by upgrading Dragon1 with an escape tower, ECLSS, etc. instead of building an entirely new spacecraft. 

Incidentally, SNC said that cargo and crewed DC were common for 85% of the spacecraft. I don't think that you can say that for Dragons 1 & 2.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Prettz on 01/09/2017 07:51 pm
Incidentally, SNC said that cargo and crewed DC were common for 85% of the spacecraft. I don't think that you can say that for Dragons 1 & 2.
And as they get into real development on the cargo version, how long will that stay true?
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Robotbeat on 01/09/2017 08:00 pm
Okay, y'all stop making my point for me! :D

Which is: I doubt the transition from cargo DC to crew DC would be any less than from cargo Dragon to crew Dragon.

I am not sure you compare these two situations. Except for the upcoming drop test, SNC will not be getting any more commercial crew funding from NASA whereas SpaceX will.

Dragon2 is very different from Dragon1. But had SpaceX not received commercial crew funding from NASA, they likely could have saved money by upgrading Dragon1 with an escape tower, ECLSS, etc. instead of building an entirely new spacecraft. 

Incidentally, SNC said that cargo and crewed DC were common for 85% of the spacecraft. I don't think that you can say that for Dragons 1 & 2.
If you look at the early crew Dragon concepts, you could easily say that.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: yg1968 on 01/09/2017 08:02 pm
Incidentally, SNC said that cargo and crewed DC were common for 85% of the spacecraft. I don't think that you can say that for Dragons 1 & 2.
And as they get into real development on the cargo version, how long will that stay true?

They are not going to be working on the crewed DC version (or very little). So the cargo version will be the baseline for a crewed DC version, if there is ever one.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: yg1968 on 01/09/2017 11:36 pm
Here is an article on DC:

http://www.geekwire.com/2016/nasas-backing-fuels-more-interest-in-dream-chaser-space-plane/

Quote
The financial terms have yet to be nailed down, but in his interviews, Sirangelo says there’s a general sense that a contract for at least six spaceflights should be worth at least a billion dollars, if not more.
[...]
So what now? Later this year, a Dream Chaser prototype will be put through its second aerodynamic test glide through the atmosphere
[...]
For the upcoming test, the prototype will be dropped from a helicopter, Sirangelo said. After that, the atmospheric tests will be conducted at higher altitudes, using a carrier system that has yet to be identified.
Is this the first time SNC actually said they were building two orbital vehicles for it? (Or had I just not noticed before?)

I've seen it mentioned before. I think NASA insisted on it, to make sure they could handle the loss of one vehicle.

I don't think that having two spacecrafts is a requirement per the RFP. However, having more than one spacecraft makes it much easier to meet the (Launch On Need) requirement of being able to launch a CR2 mission within 60 days of the prior one. See below:

Quote from: Pages 85 and 86 of the RFP
2.6   LAUNCH ON NEED (LON)
A Launch On Need (LON) capability should be provided in the event there is an interruption in the provision of cargo services from any of the providers through the life of the contract.
The Contractor should meet the following technical capabilities to satisfy LON:
(a)   Able to be called up after the Contractor’s initial CRS2 flight,
(b)   Able to launch within two months after launch of a planned CRS2 mission,
(c)   Accommodate up to the full complement of pressurized cargo that had been planned for the next mission, as applicable to the standard mission, , including standard powered payloads and standard late load for launch and return,
(d)   The next planned launch following a LON can be as early as 2 months from completion of the LON mission,
(e)   In any 12 month period, accommodate one (1) LON mission in addition to the planned flight rate.

http://forum.nasaspaceflight.com/index.php?topic=34093.msg1262708#msg1262708
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Kryten on 01/20/2017 06:45 pm
https://twitter.com/erobinson/status/822475780391219201
Quote
Uh any idea what this secret space shuttle in Boulder is @spacecom @space
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Rocket Science on 01/21/2017 08:33 pm
https://twitter.com/erobinson/status/822475780391219201
Quote
Uh any idea what this secret space shuttle in Boulder is @spacecom @space
Did she get pulled over for speeding?? ;D
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: rayleighscatter on 01/26/2017 11:54 pm
And this time she isn't sporting any extra accessories on her nose.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: adrianwyard on 01/27/2017 02:36 am
I doubt they'd ship her with the boom attached, so we may yet see one added.

The article mentions 'months' of testing before flight. I hope that goes smoothly and they don't run into the hot weather and so further delays. As scheduled it's already going to be three and a half years between flight 1 and 2... and some of us are impatient :-)
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: JAFO on 01/27/2017 05:47 am
https://twitter.com/erobinson/status/822475780391219201 (https://twitter.com/erobinson/status/822475780391219201)
Quote
Uh any idea what this secret space shuttle in Boulder is @spacecom @space

"But Officer, I wasn't driving too fast. I was just flying too low!!"
"You'd speed too if you were being chased by a spaceship."
"Before she was DreamChaser, she was TruckChaser."


 ;D
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Rocket Science on 01/27/2017 12:58 pm
https://twitter.com/erobinson/status/822475780391219201 (https://twitter.com/erobinson/status/822475780391219201)
Quote
Uh any idea what this secret space shuttle in Boulder is @spacecom @space

"But Officer, I wasn't driving too fast. I was just flying too low!!"
"You'd speed too if you were being chased by a spaceship."
"Before she was DreamChaser, she was TruckChaser."


 ;D
DC: Something wrong officer?
Officer:  Do you know how fast you were going?
DC: Uh, no...
Officer: Why not?
DC: My air data probe got blocked when this big white plastic bag flew up into my face...
Office: OK, you can go... drive, err... fly carefully...
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Lar on 01/27/2017 04:32 pm
I think that image demonstrates just how small this ship is, although I'm not clear if this is the downsized version or regular size...
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Rocket Science on 01/27/2017 07:44 pm
I think that image demonstrates just how small this ship is, although I'm not clear if this is the downsized version or regular size...
Size regular... ;D
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: yg1968 on 01/29/2017 02:37 pm
Yes. The wings are detached but other than, it is regular size.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: brickmack on 01/29/2017 09:16 pm
I think that image demonstrates just how small this ship is, although I'm not clear if this is the downsized version or regular size...

Is the downsized version still even in development? The Cargo version is the same size, just with folding wings. AFAIK the only downsized version was for Stratolaunch and that deal fell through
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Rocket Science on 01/30/2017 08:40 pm
I think that image demonstrates just how small this ship is, although I'm not clear if this is the downsized version or regular size...

Is the downsized version still even in development? The Cargo version is the same size, just with folding wings. AFAIK the only downsized version was for Stratolaunch and that deal fell through
Sure, just bring money...
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Rocket Science on 01/31/2017 10:08 pm
Thanks for the great article Chris G! :) Hard to believe it was four years ago since she last flew...
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Rocket Science on 02/09/2017 04:44 pm
I was looking at the bumps on the nose of DC under her wrap from the update thread and it looks like she "may" be sporting Nonobtrusive flush air data sensors this time instead of the boom...
https://www.nasa.gov/centers/dryden/news/DTRS/1995/HTML/TM-104316/
https://www.researchgate.net/figure/282864693_fig8_Flush-air-data-system-installation-at-the-nose-of-the-F-18-Systems-Research-Aircraft-1

Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: lars.lauritsen.1 on 02/09/2017 05:22 pm
Wow that is so awesome stuff 😊 👍

Sendt fra min F8331 med Tapatalk

Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: yg1968 on 02/13/2017 05:03 pm
I will try to post a few quotes from the article tonight. I have access to it through my phone's Twitter account for some reason. Essentially, SNC suggested this Hubble servicing mission with a crewed DC (twice) to the transition team. The transition team said that this is the kind of decision that would have to be made by the NASA Administrator but that the Trump administration is open to private-public partnerships especially if a mission can be done prior to 2020.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: redliox on 02/13/2017 05:27 pm
Officials Mull Proposal for Manned Mission to Refurbish Hubble Telescope:
https://www.wsj.com/articles/officials-mull-proposal-for-manned-mission-to-refurbish-hubble-telescope-1486927198

Here's a non-paywall version of the story.

http://www.astronomy.com/news/2017/02/potential-hubble-repair-mission

Hmm...Dream Chaser repairing the Hubble?  That is an interesting idea.  I'd rank it as difficult but not impossible.  I'd be curious to see how SNC would handle such a job.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: adrianwyard on 02/13/2017 06:12 pm
Flying a manned mission of any sort only one year after the first cargo flight seems implausible in the extreme, let alone a Hubble repair mission.

But it raises an interesting question. Assuming cargo Dream Chaser works as advertised, what is the spacecraft most suited to a crewed Hubble repair mission? Is a human-rated DC clearly a better option than using Dragon 2, Starliner, or later Orion?

At first glance the DC cargo module looks potentially useful. New instruments could be mounted on it, and old ones stored for disposal. It could serve as an airlock too. If necessary - and your budget is up to it - you could mount a disposable robotic arm there too.

But the Dragon 2 trunk seems just as useful. (I don't think you need an airlock.) And it will be crew-rated by 2020. Remember, DC will not have an abort system, so may never be crew rated.

At the end of the day, I think this is just SNC being politically and media savvy. Trump and his supporters seem to like the idea of reversing anything that happened in the last 8 years, and many people are under the false impression that the Obama administration cancelled the shuttle. So... Trump would surely like the idea of bringing it back, new and improved.

I'd bet this is just SNC just staying visible to the people who now hold the purse-strings rather than a serious proposal.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: a_langwich on 02/13/2017 06:54 pm
I'd bet this is just SNC just staying visible to the people who now hold the purse-strings rather than a serious proposal.

I'd lean toward this, too, but I've got to give credit to SNC for knocking on every door, and (not in this case, but others) bringing people to the table who might not otherwise have considered what they might do in space.  As someone who has floated some crazy ideas myself, I can't fault their creativity in coming up with potential uses for DC.  Unfortunately, the ultimate judge is the marketplace, and that has so far not swung their way.

I'm guessing the NASA side of this is very heavily in the "pre-decision investigation" territory, so they may have started with the stipulation that a crewed DC was available, to see what sort of capability that might provide to Hubble and whether it would even be worth it if available.  If that seemed like it might be worthwhile, then perhaps they would add in consideration of the state of crewed DC and perhaps what it would cost to finish it out (eg launch abort flights at a minimum)?

I'm with you, though, if you are poking around the idea of another Hubble service mission, it would make sense to look at Dragon2 and Starliner and DC, and compare their capabilities.  Certainly Dragon2 and Starliner will be available and certified for human use sooner.

Would instruments like the Cosmic Origins Spectrograph or Wide Field Camera 3 fit into DC's cargo module or Dragon2's trunk?
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: whitelancer64 on 02/13/2017 07:11 pm
*snip* Remember, DC will not have an abort system, so may never be crew rated.

*snip*

DC does have an abort capability, it would fire its main engines to pull away from a failing rocket.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: IanThePineapple on 02/13/2017 07:24 pm
*snip* Remember, DC will not have an abort system, so may never be crew rated.

*snip*

DC does have an abort capability, it would fire its main engines to pull away from a failing rocket.

Aren't its main engines not incredibly powerful?
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: adrianwyard on 02/13/2017 07:29 pm
*snip* Remember, DC will not have an abort system, so may never be crew rated.

*snip*

DC does have an abort capability, it would fire its main engines to pull away from a failing rocket.

I'm assuming such a mission would be adapted from the cargo version, which does not have the hybrid abort motors proposed for the crew variant. And of course it launches inside a fairing, which is bad if you want to abort, but good for a repair mission because it includes the cargo module, i.e. a place to mount sizable instruments and repair gear - and a way to dispose of old instruments.

The old plans for HL-20 did include a 'towed package' stored in the stage adapter, so you could resurrect that idea, but it seems less useful than the DC cargo module or Dragon trunk.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Rocket Science on 02/13/2017 07:40 pm
I'm going to bet that the hybrid motors have gone to way of the dodo for any crew DC variant...
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: adrianwyard on 02/13/2017 08:12 pm
Right. There was speculation that SNC would switch over to Orbitec abort motors after they acquired the company in 2014. Propane-NOx IIRC. But then they lost the crew contract, and cargo DC was spec'd without them.

Orbitec are reportedly providing the thrusters for cargo DC, so it's possible they could develop large motors for abort at some point.

Side note: info on the cargo DC thrusters is still surprisingly hard to find, i.e. which propellants will be used, spark ignition? Anyone heard anything of late?
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Rocket Science on 02/13/2017 08:20 pm
Right. There was speculation that SNC would switch over to Orbitec abort motors after they acquired the company in 2014. Propane-NOx IIRC. But then they lost the crew contract, and cargo DC was spec'd without them.

Orbitec are reportedly providing the thrusters for cargo DC, so it's possible they could develop large motors for abort at some point.

Side note: info on the cargo DC thrusters is still surprisingly hard to find, i.e. which propellants will be used, spark ignition? Anyone heard anything of late?
All I know is that it will still be non-toxic which is one of their selling points...
http://www.sncspace.com/Mediakit/FAQ
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Lars-J on 02/13/2017 11:55 pm
I will try to post a few quotes from the article tonight. I have access to it through my phone's Twitter account for some reason. Essentially, SNC suggested this Hubble servicing mission with a crewed DC (twice) to the transition team. The transition team said that this is the kind of decision that would have to be made by the NASA Administrator but that the Trump administration is open to private-public partnerships especially if a mission can be done prior to 2020.

That's .. interesting ... but seems more like wishful thinking than anything else.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: TrevorMonty on 02/14/2017 03:22 am
May be possible with cargo version plus a crew dragon or star liner. Have crew rendezvous with DC at Hubble, transfer to DC. Use its robotic arm and airlock for repair mission, then transfer back to crew vehicle for return.

NB developing a crew DC by 2020 maybe big ask especially if NASA is not helping fund it.

Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: brickmack on 02/14/2017 06:32 pm
The old plans for HL-20 did include a 'towed package' stored in the stage adapter, so you could resurrect that idea, but it seems less useful than the DC cargo module or Dragon trunk.

DC Crew was also proposed to support such a thing, was shown able to carry modules about the size of DC Cargos expendable module.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Lars-J on 03/28/2017 06:40 am
From the update thread:
The problem with the crewed version is that it has to be launched inside a payload shroud with wings folded which vastly complicates the abort system.

The reason it has to be launched in a shroud is that otherwise the booster is highly unstable in pitch due to the lifting surface at the nose. Dyna-Soar tried to fix this problem with big tail fins on the boosters but wind tunnel tests revealed unpredictable interactions between the spacecraft wing and the booster fins.

Also, I think NASA would be scared stiff by the wing folding joints. The landing gear doors were a lot of trouble on Shuttle but the long wing joints on the "navalized" Dream Chaser are just asking for a burn-through.

DC does not have to be in launched in a shroud. That's just the development shortcut taken the cargo version, to reduce the amount of work needed to counteract/handle the lifting surfaces. The crewed DC was going to be launched without a shroud. It is not an unsolvable problem, but it is one big hurdle that will have to be cleared if they are going to ever fly a crewed version.

Apparently they thought having foldable wings was easier than solving the aero loads during launch issue.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: adrianwyard on 03/28/2017 02:58 pm
SNC's Sirangelo is on record several times saying launching without a fairing was found not to be a problem; it was extensively tested in wind-tunnels. I suppose it's possible he spoke prematurely, and problems were discovered late in wind tunnel testing, but the reason cargo DC *has* to launch in a fairing is it is attached to the cargo module with exposed payloads.

In order to fit in a fairing the wings have to fold, but a happy side effect is transporting DC becomes easier as it will now fit inside smaller cargo aircraft.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: psloss on 03/28/2017 07:41 pm
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: john smith 19 on 03/28/2017 08:03 pm

A full sized  crew rated CFC structure lifting body, with low maintenance TPS and flush mount air data system.

These are just some of the reason why DC remains the most advanced design of the COTS programme.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Jester on 04/03/2017 09:51 am
@psloss

Wait, its assembled and ready for captive ? Shouldnt this be in the update thread ? source of that capture ?
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: shuttle_buff on 04/17/2017 12:33 am
Let's hope the next drop test is soon. The development of this spacecraft is taking FOREVER! Started in 2005? It's 2017!

I know they lost out to Boeing and SpaceX a few years ago but by the time they get this ship operational the ISS will be retiring and I'll be dead!

Really I think it's great system and want to see it work but it can't land on the Moon or Mars. It's a low earth orbit and back access system. SNC really needs some sense of urgency. Things are moving way to slow in my opinion.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: yg1968 on 04/17/2017 03:37 pm
The cargo DC should be ready in late 2019 or 2020.

For crewed DC, I wouldn't hold my breath. My guess is that it is kept alive in case that a new contract opportunity arises but that's about it. 
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: rockets4life97 on 04/18/2017 04:53 pm
From the update thread:

This French article from March 21st 2017 says that SNC has not yet decided on a LV for cargo DC except for its first flight (which will be on an Atlas V). In the running are the following LVs:

Ariane 6 with 4 boosters
Blue Origin's New Glenn
ULA's Vulcan
SpaceX's Falcon 9


http://www.futura-sciences.com/sciences/actualites/dream-chaser-ariane-6-lancera-t-elle-mini-navette-dream-chaser-66745/

I have a hard time believing Falcon 9 is really in the running. I don't think SpaceX will be launching anything other than Dragon to the ISS. I can't see how it is their interest to help out a direct competitor.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: RonM on 04/18/2017 04:57 pm
From the update thread:

This French article from March 21st 2017 says that SNC has not yet decided on a LV for cargo DC except for its first flight (which will be on an Atlas V). In the running are the following LVs:

Ariane 6 with 4 boosters
Blue Origin's New Glenn
ULA's Vulcan
SpaceX's Falcon 9


http://www.futura-sciences.com/sciences/actualites/dream-chaser-ariane-6-lancera-t-elle-mini-navette-dream-chaser-66745/

I have a hard time believing Falcon 9 is really in the running. I don't think SpaceX will be launching anything other than Dragon to the ISS. I can't see how it is their interest to help out a direct competitor.

Money is money.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: brickmack on 04/18/2017 07:59 pm
I have a hard time believing Falcon 9 is really in the running. I don't think SpaceX will be launching anything other than Dragon to the ISS. I can't see how it is their interest to help out a direct competitor.

SNC is no longer a direct competitor to SpaceX, they only compete prior to the contract initially being awarded. They're still going to buy flights from someone, its in SpaceX's interest to get as many launch contracts as they can and prevent their actual competitors from getting launches.

Plus, ULA has already sold flights to SNC and OATK even though they're partially owned by Boeing, and Boeing has looked into non-ULA launch options as well
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: yg1968 on 04/19/2017 01:36 pm
From the update thread:

This French article from March 21st 2017 says that SNC has not yet decided on a LV for cargo DC except for its first flight (which will be on an Atlas V). In the running are the following LVs:

Ariane 6 with 4 boosters
Blue Origin's New Glenn
ULA's Vulcan
SpaceX's Falcon 9

The article says that SNC will make a decision this spring on its LV for DC.

http://www.futura-sciences.com/sciences/actualites/dream-chaser-ariane-6-lancera-t-elle-mini-navette-dream-chaser-66745/

I have a hard time believing Falcon 9 is really in the running. I don't think SpaceX will be launching anything other than Dragon to the ISS. I can't see how it is their interest to help out a direct competitor.

I have trouble believing that too. I was under the impression that the F9 fairing wasn't tall enough for cargo DC. In certain presentations, SNC has indicated that FH (presumably with a taller fairing) would be required.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: RonM on 04/19/2017 03:24 pm
From the update thread:

This French article from March 21st 2017 says that SNC has not yet decided on a LV for cargo DC except for its first flight (which will be on an Atlas V). In the running are the following LVs:

Ariane 6 with 4 boosters
Blue Origin's New Glenn
ULA's Vulcan
SpaceX's Falcon 9

The article says that SNC will make a decision this spring on its LV for DC.

http://www.futura-sciences.com/sciences/actualites/dream-chaser-ariane-6-lancera-t-elle-mini-navette-dream-chaser-66745/

I have a hard time believing Falcon 9 is really in the running. I don't think SpaceX will be launching anything other than Dragon to the ISS. I can't see how it is their interest to help out a direct competitor.

I have trouble believing that too. I was under the impression that the F9 fairing wasn't tall enough for cargo DC. In certain presentations, SNC has indicated that FH (presumably with a taller fairing) would be required.

If F9 and a custom fairing is still competitive, then F9 is still in the running. Sure, the custom fairing will be more expensive, but the overall cost could be lower than the competition.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Rocket Science on 04/19/2017 03:26 pm
From the update thread:

This French article from March 21st 2017 says that SNC has not yet decided on a LV for cargo DC except for its first flight (which will be on an Atlas V). In the running are the following LVs:

Ariane 6 with 4 boosters
Blue Origin's New Glenn
ULA's Vulcan
SpaceX's Falcon 9

The article says that SNC will make a decision this spring on its LV for DC.

http://www.futura-sciences.com/sciences/actualites/dream-chaser-ariane-6-lancera-t-elle-mini-navette-dream-chaser-66745/

I have a hard time believing Falcon 9 is really in the running. I don't think SpaceX will be launching anything other than Dragon to the ISS. I can't see how it is their interest to help out a direct competitor.

I have trouble believing that too. I was under the impression that the F9 fairing wasn't tall enough for cargo DC. In certain presentations, SNC has indicated that FH (presumably with a taller fairing) would be required.

If F9 and a custom fairing is still competitive, then F9 is still in the running. Sure, the custom fairing will be more expensive, but the overall cost could be lower than the competition.
Especially if they recover the fairings! ;)
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: baldusi on 04/19/2017 09:39 pm
Please remember that DreamChaser is expected to use a 552 Atlas V. It should be able to do around 21 tonnes to LEO. Which is around what SpaceX claims Falcon 9 to do in expendable mode (22 tonnes). So it would either need a fully expendable Falcon 9 or a RTLS Falcon Heavy. An Atlas V 552 should cost quite a penny, probably in the 110~120M range. How much would SpaceX charge for a Falcon Heavy? Which would be the expected reliability and schedule margins? I wouldn't count Atlas V nor Vulcan out, yet.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Flying Beaver on 04/19/2017 10:02 pm
Dream Chaser Cargo should weight in at about 14.5tons (9ton ship, 5.5ton cargo).

14.5tons is in the Falcon 9's range for LEO orbit, with a GTO style S1 landing profile. Remember a Iridium mission is a little over 10tons, and the first stage is still about to do a major divert, downrange ASDS landing.

For FH though, $90M for a land-able mission. http://www.spacex.com/about/capabilities (http://www.spacex.com/about/capabilities)

Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: envy887 on 04/20/2017 12:56 am
Please remember that DreamChaser is expected to use a 552 Atlas V. It should be able to do around 21 tonnes to LEO. Which is around what SpaceX claims Falcon 9 to do in expendable mode (22 tonnes). So it would either need a fully expendable Falcon 9 or a RTLS Falcon Heavy. An Atlas V 552 should cost quite a penny, probably in the 110~120M range. How much would SpaceX charge for a Falcon Heavy? Which would be the expected reliability and schedule margins? I wouldn't count Atlas V nor Vulcan out, yet.

Gunter says DreamChaser is expected to launch on Atlas V 412
http://space.skyrocket.de/img_lau/atlas-5-412__dream-chaser__1.jpg

Is the dual-engined Centaur required for redundancy? It certainly doesn't seem to be for payload capability.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: LastStarFighter on 04/20/2017 01:27 am
Please remember that DreamChaser is expected to use a 552 Atlas V. It should be able to do around 21 tonnes to LEO. Which is around what SpaceX claims Falcon 9 to do in expendable mode (22 tonnes). So it would either need a fully expendable Falcon 9 or a RTLS Falcon Heavy. An Atlas V 552 should cost quite a penny, probably in the 110~120M range. How much would SpaceX charge for a Falcon Heavy? Which would be the expected reliability and schedule margins? I wouldn't count Atlas V nor Vulcan out, yet.

Gunter says DreamChaser is expected to launch on Atlas V 412
http://space.skyrocket.de/img_lau/atlas-5-412__dream-chaser__1.jpg

Is the dual-engined Centaur required for redundancy? It certainly doesn't seem to be for payload capability.

552 is for Dream Chaser cargo version. 412 is for Dream Chaser crew version. The lack of crew, cargo container and payload fairing allow for the increase in solids to maximize payload. Dual engine is just for performance increase by minimizing gravity loses.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: yg1968 on 04/23/2017 05:50 pm
At 14m30s, Vern Thorp from ULA said that they were making modifications, this year, to the White Room for other customers in the future.

It's not clear what he meant by other customers. Presumably, he meant modifications for space tourist flights but he may have meant for other companies such as SNC:

https://www.youtube.com/watch?v=Wb0eLZISnxE

See above.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: JAFO on 05/26/2017 02:08 am
Quote from: NASA
from
CCP Status report
http://www.nasa.gov/directorates/heo/nac-heoc (http://www.nasa.gov/directorates/heo/nac-heoc)

Approach & Landing Test 2 (ALT-2) is CCiCap Milestone 4B and CRS2
Integration Milestone 5
– Full scale Dream Chaser® engineering test article (ETA) unpowered approach & landing
test (ALT-2)
- Ship to AFRC Q1 2017 for Range and Taxi Testing then Approach & Landing Test 2
- Primary Objectives:
o Collect subsonic aerodynamic data to validate wind tunnel and CFD aero results
o Validation of spacecraft low-speed aerodynamic flying qualities – stability and control
o Validate subsonic orbital vehicle flight software and GN&C functionality.

Key Dream Chaser test vehicle Activities, Q3-Q4 2016
– Successfully executed a large number of offline, on-vehicle and integrated tests in
Louisville, CO facility to verify system design requirements and validate system function.
– Landing Gear tests identified nose/main landing gear (NLG/MLG) deploy sequence issue
– Remaining work planned in Colorado before Jan 2017 ship to AFRC/EAFB
- Complete Landing Gear hydraulic system modifications and acceptance testing
  Avionics Checkout with Flight Fault Tolerant Flight Computers using Flight Software ver. 3.0 (flight load)
   Polarity Test, Multi-Actuator Test, pre-Ship Day-In-The-Life Test, Radar Altimeter installs,
  Flush Air Data System Checkout, Rollout Ground Resonance Test
  Prep ETA for ship before Christmas, Ship to AFRC/EAFB 1st week January 2017

"Execute Free Flight Test (ALT2) March 2017, complete milestone NLT Aug
2017 (current CCiCap 5-year period of performance).

You'll hardly find a bigger DC amazing people than myself, but (WADR to the Mods), when she was delivered to Dryden/Armstrong I predicted that there was no way SNC would make a March free flight, they would take the time to make sure everything was A-OK, were most likely looking at September-October, and my post was deleted.

I don't mind that my post was moderated. I'm just glad SNC is not rushing and is taking the time to make sure she's ready to go. Getting near time to dig my "I heart DC" t-shirt out.
 

https://twitter.com/sierranevcorp/status/867833578528284673 (https://twitter.com/sierranevcorp/status/867833578528284673)

Dream Chaser® spacecraft at dawn.


Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: GWH on 05/26/2017 03:15 am
Please remember that DreamChaser is expected to use a 552 Atlas V. It should be able to do around 21 tonnes to LEO. Which is around what SpaceX claims Falcon 9 to do in expendable mode (22 tonnes). So it would either need a fully expendable Falcon 9 or a RTLS Falcon Heavy. An Atlas V 552 should cost quite a penny, probably in the 110~120M range. How much would SpaceX charge for a Falcon Heavy? Which would be the expected reliability and schedule margins? I wouldn't count Atlas V nor Vulcan out, yet.

Gunter says DreamChaser is expected to launch on Atlas V 412
http://space.skyrocket.de/img_lau/atlas-5-412__dream-chaser__1.jpg

Is the dual-engined Centaur required for redundancy? It certainly doesn't seem to be for payload capability.

552 is for Dream Chaser cargo version. 412 is for Dream Chaser crew version. The lack of crew, cargo container and payload fairing allow for the increase in solids to maximize payload. Dual engine is just for performance increase by minimizing gravity loses.
To answer baldusi an Atlas 551 starts at $163 according to ULA's rocketbuilder.com. Add the cost of a second RL-10 to that.

Sent from my SM-G903W using Tapatalk

Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Rocket Science on 05/31/2017 01:44 am
Quote from: NASA
from
CCP Status report
http://www.nasa.gov/directorates/heo/nac-heoc (http://www.nasa.gov/directorates/heo/nac-heoc)

Approach & Landing Test 2 (ALT-2) is CCiCap Milestone 4B and CRS2
Integration Milestone 5
– Full scale Dream Chaser® engineering test article (ETA) unpowered approach & landing
test (ALT-2)
- Ship to AFRC Q1 2017 for Range and Taxi Testing then Approach & Landing Test 2
- Primary Objectives:
o Collect subsonic aerodynamic data to validate wind tunnel and CFD aero results
o Validation of spacecraft low-speed aerodynamic flying qualities – stability and control
o Validate subsonic orbital vehicle flight software and GN&C functionality.

Key Dream Chaser test vehicle Activities, Q3-Q4 2016
– Successfully executed a large number of offline, on-vehicle and integrated tests in
Louisville, CO facility to verify system design requirements and validate system function.
– Landing Gear tests identified nose/main landing gear (NLG/MLG) deploy sequence issue
– Remaining work planned in Colorado before Jan 2017 ship to AFRC/EAFB
- Complete Landing Gear hydraulic system modifications and acceptance testing
  Avionics Checkout with Flight Fault Tolerant Flight Computers using Flight Software ver. 3.0 (flight load)
   Polarity Test, Multi-Actuator Test, pre-Ship Day-In-The-Life Test, Radar Altimeter installs,
  Flush Air Data System Checkout, Rollout Ground Resonance Test
  Prep ETA for ship before Christmas, Ship to AFRC/EAFB 1st week January 2017

"Execute Free Flight Test (ALT2) March 2017, complete milestone NLT Aug
2017 (current CCiCap 5-year period of performance).

You'll hardly find a bigger DC amazing people than myself, but (WADR to the Mods), when she was delivered to Dryden/Armstrong I predicted that there was no way SNC would make a March free flight, they would take the time to make sure everything was A-OK, were most likely looking at September-October, and my post was deleted.

I don't mind that my post was moderated. I'm just glad SNC is not rushing and is taking the time to make sure she's ready to go. Getting near time to dig my "I heart DC" t-shirt out.
 

https://twitter.com/sierranevcorp/status/867833578528284673 (https://twitter.com/sierranevcorp/status/867833578528284673)

Dream Chaser® spacecraft at dawn.
Thanks for my new desktop background! 8)
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: jgoldader on 06/04/2017 03:38 pm
Has SNC released any more info on the cargo module?  I'm trying to model it, and dimensions would be hugely helpful.  I can get close scaling from the renderings, but real numbers would be great.  Thanks!
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: hans_ober on 07/19/2017 02:38 pm
Wrt them announcing Atlas 552: Pricey. They could have a lot by switching over the F9.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Jim on 07/19/2017 02:46 pm
Wrt them announcing Atlas 552: Pricey. They could have a lot by switching over the F9.

No, F9 is a competitor
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: gongora on 07/19/2017 03:30 pm
Wrt them announcing Atlas 552: Pricey. They could have a lot by switching over the F9.

If it needs an Atlas 552 then it probably couldn't launch on F9, would need to be FH.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Rebel44 on 07/19/2017 03:46 pm
Wrt them announcing Atlas 552: Pricey. They could have a lot by switching over the F9.

If it needs an Atlas 552 then it probably couldn't launch on F9, would need to be FH.
Bases on published info, Atlas 552 has slightly lower performance to LEO than expendable performance listed for  Falcon 9  (block 5)
Atlas V 552 : 20 520kg to LEO
Falcon 9: 22 800kg to LEO
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: GWH on 07/19/2017 04:00 pm
Is a Dream Chaser Cargo even able to fit in the F9/FH fairing?  It looks to be pretty long.

In comparing values, Dream Chaser Cargo capacity is 5500kg, Dragon is 6000kg BUT is seemingly volume limited at 14m3 pressurized, and it's heaviest load was ~3100kg.
What is the volumetric capacity of Dream Chaser cargo?  Tried pretty hard to find this but came up pretty empty, there may be 16m3 in DC + extra in service module but the source was pretty patchy.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Rebel44 on 07/19/2017 04:37 pm
Is a Dream Chaser Cargo even able to fit in the F9/FH fairing?  It looks to be pretty long.

In comparing values, Dream Chaser Cargo capacity is 5500kg, Dragon is 6000kg BUT is seemingly volume limited at 14m3 pressurized, and it's heaviest load was ~3100kg.
What is the volumetric capacity of Dream Chaser cargo?  Tried pretty hard to find this but came up pretty empty, there may be 16m3 in DC + extra in service module but the source was pretty patchy.

Yeah, F9/FH would need a longer fairing

Not sure about cargo volume of Dream Chaser
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: TrevorMonty on 07/19/2017 05:03 pm
NG would be good option once flying, got be lot cheaper than Atlas V552.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Lars-J on 07/20/2017 01:23 am
I am a bit surprised by the weight of the cargo DC... An Atlas V 552 won't be cheap. This so it requires three more SRBs compared to what the crew DC was baselined for, right?

I also (for some reason) expected them to be ready before 2020. But they have been forced to a slower development process since losing the commercial crew down-select.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: russianhalo117 on 07/20/2017 03:08 am
I am a bit surprised by the weight of the cargo DC... An Atlas V 552 won't be cheap. This so it requires three more SRBs compared to what the crew DC was baselined for, right?

I also (for some reason) expected them to be ready before 2020. But they have been forced to a slower development process since losing the commercial crew down-select.
the expendable module and the fact that DC is now carrying cargo that can be heavier than humans  is the reason for the choice of AV-552.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: envy887 on 07/20/2017 05:41 pm
What's the performance difference to ISS between 552 and 551?
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: GWH on 07/20/2017 08:11 pm
551 with the longest fairing is 18,813 kg according to RocketBuilder.com
$167M for "Signature Service" to LEO

According to this link here if you can open it (page 14) 552 is 20,520 kg to LEO
https://web.archive.org/web/20120921011608/http://www.faa.gov/about/office_org/headquarters_offices/ast/media/ast_developments_concepts_2010.pdf
*Credit to link from Twitter https://twitter.com/ethan829/status/888031620489515013
Also see Altas V Wikipedia entry
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: russianhalo117 on 07/20/2017 09:09 pm
551 with the longest fairing is 18,813 kg according to RocketBuilder.com
$167M for "Signature Service" to LEO

According to this link here if you can open it (page 14) 552 is 20,520 kg to LEO
https://web.archive.org/web/20120921011608/http://www.faa.gov/about/office_org/headquarters_offices/ast/media/ast_developments_concepts_2010.pdf
*Credit to link from Twitter https://twitter.com/ethan829/status/888031620489515013
Also see Atlas V Wikipedia entry
That is for LEO-Reference (200 km circular at 28.7 deg) not LEO-ISS (407 km circular at 51.6 deg).
Source (AV info last Updated in 2013): http://www.ulalaunch.com/uploads/docs/Launch_Vehicles/AV_DIV_product_card.pdf
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: yg1968 on 07/27/2017 05:13 pm
This has probably been discussed before but is there any reasons that DC could not fly to cislunar space?

I remember that SNC's original plans was that DC could fly to BLEO but some time after that, they changed their mind and said that DC was LEO only.

But my question is more whether it would be difficult to adapt DC for BLEO since NASA said that it will need cargo services to the DSG.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: intrepidpursuit on 07/27/2017 09:41 pm
This has probably been discussed before but is there any reasons that DC could not fly to cislunar space?

I remember that SNC's original plans was that DC could fly to BLEO but some time after that, they changed their mind and said that DC was LEO only.

But my question is more whether it would be difficult to adapt DC for BLEO since NASA said that it will need cargo services to the DSG.

With the cargo module is has more space and has solar panels, so it would seem that in theory it could. There is more to loiter time than just solar panels, but the cargo section would seem to afford them some more design freedom then keeping everything inside the OML.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: brickmack on 07/27/2017 10:54 pm
With the cargo module is has more space and has solar panels, so it would seem that in theory it could. There is more to loiter time than just solar panels, but the cargo section would seem to afford them some more design freedom then keeping everything inside the OML.

Internal volume isn't really a time issue, just affects the number of flights needed to deliver a certain cargo amount. It would be helpful for a crew flight, but I don't think the current expansion module concept is very applicable there (requires a fairing which inhibits an abort), if they needed extra space on a crew mission they'd probably build a pressure vessel into the boattail instead. And needing a fairing also means the wings have to fold up, which could be a much bigger safety issue on high-speed reentries (I kinda doubt even the crew variant could survive that, so lets not put extra failure points in). As for solar panels, SNC has previously presented solar array concepts that would deploy from the rear of the spaceplane itself, or from a much smaller expendable module. And with the greater delta v requirements for a NRHO or LDRO mission, mass isn't something they have available to waste anyway. I think the extra module is probably either neutral or a net negative for a cislunar variant
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Khadgars on 07/27/2017 11:20 pm
This has probably been discussed before but is there any reasons that DC could not fly to cislunar space?

I remember that SNC's original plans was that DC could fly to BLEO but some time after that, they changed their mind and said that DC was LEO only.

But my question is more whether it would be difficult to adapt DC for BLEO since NASA said that it will need cargo services to the DSG.

I don't believe it could withstand re-entry coming from the moon.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: CameronD on 07/28/2017 01:17 am
This has probably been discussed before but is there any reasons that DC could not fly to cislunar space?

I remember that SNC's original plans was that DC could fly to BLEO but some time after that, they changed their mind and said that DC was LEO only.

But my question is more whether it would be difficult to adapt DC for BLEO since NASA said that it will need cargo services to the DSG.

I don't believe it could withstand re-entry coming from the moon.

Well, they can make it to orbit in the movie theatre:  ;D

(http://s3.amazonaws.com/kidzworld_photo/images/2017130/62eab682-bec6-4579-b55c-f398d6973087/space-between-us-mars-shuttle.jpg)

https://en.wikipedia.org/wiki/The_Space_Between_Us_(film)


Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Patchouli on 07/31/2017 08:02 pm
This has probably been discussed before but is there any reasons that DC could not fly to cislunar space?

I remember that SNC's original plans was that DC could fly to BLEO but some time after that, they changed their mind and said that DC was LEO only.

But my question is more whether it would be difficult to adapt DC for BLEO since NASA said that it will need cargo services to the DSG.

I don't believe it could withstand re-entry coming from the moon.

I remember reading it would need a couple of hundred pounds of ablative added to the hottest parts and a skip reentry used.
A BLEO variant probably would need other changes such as much more delta V to be able to perform any useful missions.
This likely would mean changing everything inside around which would make it effectively a new vehicle or adding a full service module which would be big development program in it's own right.

Well, they can make it to orbit in the movie theatre:  ;D

(http://s3.amazonaws.com/kidzworld_photo/images/2017130/62eab682-bec6-4579-b55c-f398d6973087/space-between-us-mars-shuttle.jpg)

https://en.wikipedia.org/wiki/The_Space_Between_Us_(film)




I think it also showed up in a cut scene in the Martian.
Not sure why they cut it out.
https://www.youtube.com/watch?v=Y7V-ROsP0oc
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: dwheeler on 08/25/2017 05:33 pm
https://www.youtube.com/watch?v=jeMndeNG7cw (https://www.youtube.com/watch?v=jeMndeNG7cw)

I guess I don't hate that stupid nose skid as much after having seen this. Still not luvin' it though...  :D

Does anyone know if it provides any directional steering capability during the landing roll? Or are they planning on differential braking? Or something else?

Moving my above post from the UPDATE thread. Question still stands if anyone has any information about it...
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Jeff Lerner on 08/26/2017 02:29 am
On landing if a tire blows on one of the rear wheels does having a nose skid vs. A steerable nose wheel help or hinder controlling the rollout ??
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Rocket Science on 08/28/2017 02:03 am
On landing if a tire blows on one of the rear wheels does having a nose skid vs. A steerable nose wheel help or hinder controlling the rollout ??
If the tire loses pressure before landing the technique is to land with weight on the good tire using aero control surfaces until the airspeed bleeds of and allow the the tire to contact the ground then use opposite side braking to compensate for the drag from the deflated tire. If a tire blows on contact you still use aero control surfaces until they lose effectiveness and with opposite braking...
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: CameronD on 08/28/2017 06:33 am
On landing if a tire blows on one of the rear wheels does having a nose skid vs. A steerable nose wheel help or hinder controlling the rollout ??
If the tire loses pressure before landing the technique is to land with weight on the good tire using aero control surfaces until the airspeed bleeds of and allow the the tire to contact the ground then use opposite side braking to compensate for the drag from the deflated tire. If a tire blows on contact you still use aero control surfaces until they lose effectiveness and with opposite braking...

Perhaps the point is that you can't blow out a nose skid?...
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Rocket Science on 08/28/2017 01:40 pm
On landing if a tire blows on one of the rear wheels does having a nose skid vs. A steerable nose wheel help or hinder controlling the rollout ??
If the tire loses pressure before landing the technique is to land with weight on the good tire using aero control surfaces until the airspeed bleeds of and allow the the tire to contact the ground then use opposite side braking to compensate for the drag from the deflated tire. If a tire blows on contact you still use aero control surfaces until they lose effectiveness and with opposite braking...

Perhaps the point is that you can't blow out a nose skid?...
I read the question as he asked does a "steerable nose wheel help or hinder controlling the rollout ??"  My opinion is that it doesn't come much into play as the drag from the mains is greater and control should suffice with minimal off center line excursion as the vehicle is equipped...
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Rocket Science on 08/28/2017 07:44 pm
Starting to feel that Dream Chaser "mojo" again... 8) Thanks for the great update article Chris G! :)
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: rayleighscatter on 08/28/2017 08:31 pm
It's certainly not an area I claim to be an expert in but I understand that nose wheel steering in general isn't used at higher speeds (such as landing or takeoff), it's mostly used for taxiing. Steering at higher speeds is done through differential braking or with aerosurfaces. It's even considered enough of a hazard that most aircraft that have it won't allow nose wheel steering to engage above certain speeds, or if it does it only permits a few degrees of movement (something less than 7 degrees, very minimal).

So it's probably mostly a non-issue as the nose shouldn't be steering at high speeds.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: adrianwyard on 08/28/2017 08:58 pm
Another point of reference: Virgin Galactic evidently believe the same configuration is a suitable for frequent tourist flights , i.e. a winged vehicle with a nose skid and aero-surface / differential main-grear brake-steering.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Rocket Science on 08/28/2017 09:18 pm
It's certainly not an area I claim to be an expert in but I understand that nose wheel steering in general isn't used at higher speeds (such as landing or takeoff), it's mostly used for taxiing. Steering at higher speeds is done through differential braking or with aerosurfaces. It's even considered enough of a hazard that most aircraft that have it won't allow nose wheel steering to engage above certain speeds, or if it does it only permits a few degrees of movement (something less than 7 degrees, very minimal).

So it's probably mostly a non-issue as the nose shouldn't be steering at high speeds.
To add, some light aircraft don't even have nose wheel steering and it is free to caster...
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: punder on 08/28/2017 09:43 pm
To add, some light aircraft don't even have nose wheel steering and it is free to caster...

IIRC even some Soviet jet fighters used castering nose wheels, presumably to cut down on weight and complexity.

I learned to fly in an airplane with a castering nose wheel. You get used to it, but it's still a pain vs. a steering nose wheel.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: CameronD on 08/28/2017 11:04 pm
To add, some light aircraft don't even have nose wheel steering and it is free to caster...

IIRC even some Soviet jet fighters used castering nose wheels, presumably to cut down on weight and complexity.

I learned to fly in an airplane with a castering nose wheel. You get used to it, but it's still a pain vs. a steering nose wheel.

It's been explained to me during pilot training that stationary rubber hitting the tarmac at high speed melts resulting in a situation akin to aquaplaning.  Allowed to continue, the tyre will heat up and burst and a bust nose-wheel is going to result in quite a lot of damage to both the aircraft and the runway.  It's for this reason castering nose wheels were seen as a good idea - the nose wheel is always going to track in the direction the aircraft is going, no matter what the pilot is trying to do.

 
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: TomH on 08/29/2017 04:56 am
Some questions:

Is ULA signed up for Atlas V to launch all 6 of their CRS 2 launches, or is there any chance at all they'd pay less for SpaceX to launch it? And would SX be willing to do that?

After the chopper drops, is there any chance now of higher test drops from the STS Carrier aircraft, Stratolaunch, or White Knight 2 before launch to LEO? I know White Knight 2 drops were cancelled for the manned version, but years have now passed.

As far as this Hubble Servicing Mission mentioned in the article, I presume it would be limited to prop delivery, with no swap out of large components? Canada arm is probably vastly too big isn't it? Could it be cut down in size? Is any of the other servicing gear from STS missions still around and if so, could it be used from this much smaller craft? Surely some qual flights would be required before any Hubble servicing mission would be approved. Can Hubble last until that happens?
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Steven Pietrobon on 08/29/2017 07:43 am
As far as this Hubble Servicing Mission mentioned in the article, I presume it would be limited to prop delivery, with no swap out of large components?

Hubble doesn't use propellant, as it would contaminate the mirror. The mission might be just to boost the orbit and add a deorbit motor. I would think changing out parts and instruments would be difficult for an uncrewed mission.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: woods170 on 08/29/2017 07:49 am
As far as this Hubble Servicing Mission mentioned in the article, I presume it would be limited to prop delivery, with no swap out of large components?

Hubble doesn't use propellant, as it would contaminate the mirror. The mission might be just to boost the orbit and add a deorbit motor. I would think changing out parts and instruments would be difficult for an uncrewed mission.
Replace "difficult" with "impossible".
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Tomness on 08/29/2017 12:36 pm
Will Dream Chaser have to do a demonstration mission like SpaceX's COTS 2+ and Orbital ATK's Orb-D1 before operational missions?
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: ChrisGebhardt on 08/29/2017 04:37 pm
As far as this Hubble Servicing Mission mentioned in the article, I presume it would be limited to prop delivery, with no swap out of large components?

Hubble doesn't use propellant, as it would contaminate the mirror. The mission might be just to boost the orbit and add a deorbit motor. I would think changing out parts and instruments would be difficult for an uncrewed mission.
Replace "difficult" with "impossible".

Not sure why "uncrewed" gets the discussion as the proposal from SN is for a crewed mission to Hubble.

From the article. : "...and the Trump Administration in the United States is understood to be studying a proposal set forth by Sierra Nevada to use of Dream Chaser for a crewed servicing mission to the Hubble Space Telescope in the 2020s."
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Star One on 08/29/2017 07:55 pm
https://youtu.be/_du4xU4YftM
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Zed_Noir on 08/29/2017 09:57 pm
Some questions:

....

After the chopper drops, is there any chance now of higher test drops from the STS Carrier aircraft, Stratolaunch, or White Knight 2 before launch to LEO? I know White Knight 2 drops were cancelled for the manned version, but years have now passed.

....

The Shuttle Carrier Aircraft have both been retired Tom. What Stratolaunch will be up to is anybody's guess.
....


In theory the Virgin Orbital Comic Girl 747 carrier aircraft could do high altitude and hi speed drop tests of the Dream Chaser.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: brickmack on 08/30/2017 02:20 am
Not sure why "uncrewed" gets the discussion as the proposal from SN is for a crewed mission to Hubble.

From the article. : "...and the Trump Administration in the United States is understood to be studying a proposal set forth by Sierra Nevada to use of Dream Chaser for a crewed servicing mission to the Hubble Space Telescope in the 2020s."

Also, even if it was an uncrewed mission (though I can't imagine any benefit to using a spaceplane for that), NASA already studied this immediately prior to STS-125 while trying to decide how to do another servicing flight, and found an unmanned mission to be feasible (though not with as wide a scope)
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: mikes on 08/30/2017 02:21 pm
Can't help but think of the Whomobile!

http://www.retrothing.com/2010/08/the-fate-of-the-whomobile.html
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Rocket Science on 08/30/2017 03:42 pm
Congrats to SNC and to the Chinook and her flight crew! :)
https://www.youtube.com/watch?v=aJxrX42WcjQ
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Lars-J on 08/30/2017 11:10 pm
For all the hoopla about this carry test, you'd think it was an actual drop test. If this is how they cover a captive carry test, I expect some sort of Superbowl-esque production for the drop test.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: JAFO on 08/31/2017 04:37 am
Airplane I currently fly has a nose wheel steering tiller that allows +-70 deg of movement. We use it for taxiing and to position on the runway, then use the rudder for steering (which interconnects with +-8deg of NWS movement) for takeoff and landing. That's typical for the commercial aircraft I've flown, +-a few degrees.


To add, some light aircraft don't even have nose wheel steering and it is free to caster...

IIRC even some Soviet jet fighters used castering nose wheels, presumably to cut down on weight and complexity.

I learned to fly in an airplane with a castering nose wheel. You get used to it, but it's still a pain vs. a steering nose wheel.

Everything from the Diamond Katana to the B-29 and the NASA lifting bodies have had free castering nosewheels. The Katana was fun to fly but took practice to be able to taxi and park without nosewheel steering. If you ever see the B-29 an an airshow it sounds like a steampunk airplane as it gets underway with a combination of differential power and squealing hydraulic brakes. I can't find it but I recall seeing a photo of a lifting body in the flare with the nose gear cocked off to one side, it landed fine, but Milt Thompson had a few things to say about it in his books.


On landing if a tire blows on one of the rear wheels does having a nose skid vs. A steerable nose wheel help or hinder controlling the rollout ??

Dual main tire system vehicles/aircraft (Shuttle, 737, etc), the good wheel is usually certified to carry a full gear truck load in an emergency. Land, roll out straight ahead or clear the runway on a high speed taxiway and, depending on the aircraft, get a careful tow back to the gate or change the tire right there.

Single tire (DC), you're going to drag the wheel at some point. If you know beforehand (as a previous poster mentioned) that you've got a bad tire, you're going to plan to land on the good leg, hold the bad one off as long as possible, and keep it going straight with a combination of aerodynamic control, nose wheel steering, and maybe gentle opposite braking until you can't keep it up any more, then it's up to how much friction/drag the bad leg causes if you're going to be a hero or if you're going to go off the runway.

From when I've read, DC did all of that on her first flight until the wing tip had to come down and she departed control and tumbled. JMPO, but I don't think a steerable nosewheel would have been able to keep DC on the runway and from flipping over with her gear up and locked, the landing speed was too high and the friction of the dragging wingtip would have been too much for any kind of steerable nose wheel to overcome. Whether or not she could have stayed on the runway with a steerable nosewheel and a bad tire is something I'll leave to the SNC engineers.



And Congrats to SNC today, I can imagine for the last few years she's been sleeping, remembering what da Vinci said:
"Once you have tasted flight, you will forever walk the earth with your eyes turned skyward, for there you have been, and there you will always long to return."

Go Dream Chaser!!!!
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Rocket Science on 08/31/2017 12:59 pm
For all the hoopla about this carry test, you'd think it was an actual drop test. If this is how they cover a captive carry test, I expect some sort of Superbowl-esque production for the drop test.
Yes and we are planning a "half-time wardrobe malfunction" as well...
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: vapour_nudge on 08/31/2017 01:10 pm
For all the hoopla about this carry test, you'd think it was an actual drop test. If this is how they cover a captive carry test, I expect some sort of Superbowl-esque production for the drop test.
Yes and we are planning a "half-time wardrobe malfunction" as well...
But nothing like the Six Million Dollar Man opening scene I hope  ;)
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Rocket Science on 08/31/2017 01:23 pm
For all the hoopla about this carry test, you'd think it was an actual drop test. If this is how they cover a captive carry test, I expect some sort of Superbowl-esque production for the drop test.
Yes and we are planning a "half-time wardrobe malfunction" as well...
But nothing like the Six Million Dollar Man opening scene I hope  ;)
Nah no need, she already passed her roll-over survive-ability test... ;)
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: yg1968 on 08/31/2017 01:29 pm
For all the hoopla about this carry test, you'd think it was an actual drop test. If this is how they cover a captive carry test, I expect some sort of Superbowl-esque production for the drop test.

I loved their webcast. It was well done. I wished that it had continued until the end of the test.

These webcasts provide good publicity for a program that doesn't make the news as much as it should. I hope that SNC will have webcasts for their other tests as well.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: yg1968 on 08/31/2017 01:34 pm
I liked that they took questions during the webcast. One of the interesting things that Steve Lindsey said was that DC was a LEO spacecraft only. He admitted that wings aren't very useful for Mars or the Moon but said that DC's goal is to be a very good and reliable LEO spacecraft. This isn't surprising but I still appreciate their honesty on this point.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: yg1968 on 08/31/2017 03:03 pm
As far as this Hubble Servicing Mission mentioned in the article, I presume it would be limited to prop delivery, with no swap out of large components?

Hubble doesn't use propellant, as it would contaminate the mirror. The mission might be just to boost the orbit and add a deorbit motor. I would think changing out parts and instruments would be difficult for an uncrewed mission.
Replace "difficult" with "impossible".

Not sure why "uncrewed" gets the discussion as the proposal from SN is for a crewed mission to Hubble.

From the article. : "...and the Trump Administration in the United States is understood to be studying a proposal set forth by Sierra Nevada to use of Dream Chaser for a crewed servicing mission to the Hubble Space Telescope in the 2020s."

There were reports that this crewed DC mission had been proposed by SNC to Trump's NASA transition team at the beginning of 2017. But I haven't heard of it since then. Perhaps SNC will renew its "sales pitch" to the new NASA administrator.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: yg1968 on 08/31/2017 03:14 pm
Will Dream Chaser have to do a demonstration mission like SpaceX's COTS 2+ and Orbital ATK's Orb-D1 before operational missions?

No. Although, there wasn't much of a difference between a COTS demo flight and an operational CRS flight. So I don't think that it makes much of a difference. In other words, I am guessing that DC's first CRS2 flight will be treated like a demo flight by NASA and SNC. 
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: TomH on 08/31/2017 06:35 pm
Perhaps SNC will renew its "sales pitch" to the new NASA administrator.

Hubble may be dead before we have one. I still think ITSy would be better suited and flying sooner.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: QuantumG on 09/01/2017 12:41 am
Can everyone talking about SpaceX on this thread please delete their comments? FFS. Not every thread has to be about SpaceX.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: deruch on 09/02/2017 02:20 am
<moved from updates thread>
Quote
Who needs a moon to do an Eclipse... #DreamChaser #Eclipse2017 @SierraNevCorp @NASAArmstrong

https://twitter.com/dutchspace/status/903332819639967744

That's no moon.  It's a space..... ship.

https://www.youtube.com/watch?v=yS4p69KufIc
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: rockets4life97 on 11/08/2017 09:06 pm
Michael Baylor: Would the chopper used in the test show up on the flight tracker you are watching?

I'm wondering what other signs we might expect to see that I a test might be coming/in-progress.

Edit: Sorry, I didn't see the discussion thread. A mod can move if they want.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Michael Baylor on 11/08/2017 09:10 pm
Michael Baylor: Would the chopper used in the test show up on the flight tracker you are watching?

I'm wondering what other signs we might expect to see that I a test might be coming/in-progress.

Edit: Sorry, I didn't see the discussion thread. A mod can move if they want.
No other traffic in the vicinity showing up. According to the flight tracker website most helicopters do not show up as they have different tracking equipment.

https://www.flightradar24.com/how-it-works
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: JAFO on 11/08/2017 09:13 pm
 Trying not to tie up the update thread:  anyone know what type aircraft that is in the update that are circling by the runway? Methinks a 38 would be way too fast to chase a helicopter dropped dream chaser.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Rocket Science on 11/08/2017 09:21 pm
Trying not to tie up the update thread:  anyone know what type aircraft that is in the update that are circling by the runway? Methinks a 38 would be way too fast to chase a helicopter dropped dream chaser.
Beech B200 and T-34C one orbiting and one for chase and video?
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: JAFO on 11/08/2017 09:52 pm
Trying not to tie up the update thread:  anyone know what type aircraft that is in the update that are circling by the runway? Methinks a 38 would be way too fast to chase a helicopter dropped dream chaser.
Beech B200 and T-34C one orbiting and one for chase and video?

Thanks. I was out for a walk and could not see the pictures in the data block while reading the thread on my phone.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: JAFO on 11/08/2017 11:31 pm
Winds started kicking up again starting around 1100, my bet is no flight today.

http://www.intellicast.com/Local/Observation.aspx?location=USCA0715 (http://www.intellicast.com/Local/Observation.aspx?location=USCA0715)
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Rocket Science on 11/08/2017 11:47 pm
Winds started kicking up again starting around 1100, my bet is no flight today.

http://www.intellicast.com/Local/Observation.aspx?location=USCA0715 (http://www.intellicast.com/Local/Observation.aspx?location=USCA0715)
Could be, perhaps those aircraft were rehearsing or perhaps we were just imagining things... ;D
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: JAFO on 11/08/2017 11:49 pm
Winds started kicking up again starting around 1100, my bet is no flight today.

http://www.intellicast.com/Local/Observation.aspx?location=USCA0715 (http://www.intellicast.com/Local/Observation.aspx?location=USCA0715)
Could be, perhaps those aircraft were rehearsing or perhaps we were just imagining things... ;D


You gotta Dream.














I am such a geek.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: JAFO on 11/09/2017 12:51 pm
Wind check:   http://www.intellicast.com/Local/Observation.aspx?location=USCA0715
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: abaddon on 11/09/2017 02:37 pm
Regarding the new renders from the update thread: aesthetically, I really like the color scheme, it looks like an Orca.

Of course this may be a "SpaceX always releases launch renders with the rocket being equipped with black legs, but they're white" kinda thing.  Wouldn't you want more of the surface area to be white to reflect rather than absorb radiation in the visible spectrum?
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: vt_hokie on 11/09/2017 05:01 pm
Regarding the new renders from the update thread: aesthetically, I really like the color scheme, it looks like an Orca.

Of course this may be a "SpaceX always releases launch renders with the rocket being equipped with black legs, but they're white" kinda thing.  Wouldn't you want more of the surface area to be white to reflect rather than absorb radiation in the visible spectrum?

The change struck me as odd when cargo DC was first revealed, but I assume black implies tile where thermal blankets would have been?  I also just noticed that the two OMS engine nozzles are absent on the back end.  I forget if I had noted that previously, but I guess it's likely due at least in part to the cargo module and potential plume impingement.  Will the smaller RCS thrusters be sufficient for de-orbit burns?  Or is there just detail lacking in the rendering?
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Prettz on 11/09/2017 08:00 pm
Regarding the new renders from the update thread: aesthetically, I really like the color scheme, it looks like an Orca.

Of course this may be a "SpaceX always releases launch renders with the rocket being equipped with black legs, but they're white" kinda thing.  Wouldn't you want more of the surface area to be white to reflect rather than absorb radiation in the visible spectrum?

The change struck me as odd when cargo DC was first revealed, but I assume black implies tile where thermal blankets would have been?  I also just noticed that the two OMS engine nozzles are absent on the back end.  I forget if I had noted that previously, but I guess it's likely due at least in part to the cargo module and potential plume impingement.  Will the smaller RCS thrusters be sufficient for de-orbit burns?  Or is there just detail lacking in the rendering?
The RCS was always what DC would use for de-orbit. The abort engines were just for abort, so they're deleted entirely from the cargo variant. I HAVE been wondering what is in the space they used to occupy. Empty space? Ballast weight?

And was it ever discussed why the cargo DC has heat shield tiles all over the top when the crew variant didn't "need" that? Obviously it saves weight where the windows would have been, but what about the rest of it? Only thing I can think of off the top of my head is it's a consequence of cargo DC bringing back substantially more mass through reentry than crew DC was ever intended to, although I wouldn't know why that would affect the roof's heating.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: rayleighscatter on 11/09/2017 08:24 pm
I've wondered the same thing. All I could come up with is that it will be spending 6 months docked to station where it can't do any radiant heat management, and without crew the ability isn't necessary for cargo. So without the need, removing one type of TPS could simplify the flow and reduce the costs. It's really just a stab in the dark though.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: JAFO on 11/09/2017 08:37 pm
Since we're killing time, I wonder how the OTA is coming?
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Rocket Science on 11/11/2017 03:45 pm
I checked social media links and YouTube, nothing so far...
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Michael Baylor on 11/11/2017 07:38 pm
With how long it is taking to confirm this test, I am expecting STUNNING videos and STUNNING photos from SNC.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: JAFO on 11/11/2017 07:42 pm
Slow is smooth, smooth is fast. We've been waiting decades, they've been working years, give them time to safe the vehicle and celebrate.



Saint Leibowitz is watching over us.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Rocket Science on 11/11/2017 07:47 pm
Bad new travels fast... No news is good news... ;)
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: JAFO on 11/11/2017 08:58 pm
Waiting for the 5pm East coast news cycle, maybe?
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: JAFO on 11/11/2017 08:59 pm
Bad new travels fast... No news is good news... ;)

Yup, remember how fast the ALT-1 news spread?
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: rayleighscatter on 11/11/2017 09:32 pm
Waiting for the 5pm East coast news cycle, maybe?
It's a weekend, and a holiday weekend at that. I probably wouldn't expect anything until early next week at the earliest.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: JAFO on 11/11/2017 09:40 pm
Waiting for the 5pm East coast news cycle, maybe?
It's a weekend, and a holiday weekend at that. I probably wouldn't expect anything until early next week at the earliest.

Not a chance. Too many people with cell phones, even on a military base with big signs saying FLIGHTLINE PHOTOGRAPHY PROHIBITED.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Rocket Science on 11/11/2017 10:08 pm
Maybe they all went down to Poncho's to celebrate...
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Chris Bergin on 11/11/2017 10:19 pm
They did lose their very good PAO a while back. They may be using an agency now, which sucks for the media, but SNC won't really care about the media, only their customers (which to be fair, is how a lot of commercial companies work).
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: JAFO on 11/11/2017 10:33 pm
They did lose their very good PAO a while back. They may be using an agency now, which sucks for the media, but SNC won't really care about the media, only their customers (which to be fair, is how a lot of commercial companies work).

Good PR wins or loses funding battles. Look at how Elon was able to spin all those RUDs and have people cheering for Space X versus most of the airlines and their misadventures this year.


And if there was ever an underdog story that screamed for a good PR story and was waiting to have people cheering it on, it's Dream Chaser.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Rocket Science on 11/11/2017 11:08 pm
I'll cut them some slack and be content with the successful completion of the flight test... It's been a long road coming back from this...
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Michael Baylor on 11/11/2017 11:20 pm
Dream Chaser's only customer at the moment is NASA. Without NASA's contract there would be no Dream Chaser. Considering that tax payers are making it possible, I expect SNC to be very transparent with the public, even if it is technically up to NASA to do so. It's just the right thing to do.

Additionally, this test from all reports so far was a SUCCESS. Does it really take 6 hours and counting to post a video or at least announce a success? Doing so will only do them good. The more the American public is excited about space the better. It is not rocket science.

SNC, if you need an example, just go look at some of SpaceX's old videos.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Rocket Science on 11/11/2017 11:56 pm
Just to add, all information is proprietary even when is paid for by taxpayers...
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: rayleighscatter on 11/11/2017 11:56 pm
Dream Chaser's only customer at the moment is NASA.
False.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Rocket Science on 11/12/2017 01:19 am
Thank you for the great article gentlemen, I've been waiting to read this one for a long time... 8)
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Bob Shaw on 11/12/2017 01:35 am
Maybe they all went down to Poncho's to celebrate...

Or, better still, the ghost of Pancho's...
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: JAFO on 11/12/2017 01:36 am
Maybe they all went down to Poncho's to celebrate...

I hope they did. They've earned it.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Michael Baylor on 11/12/2017 05:24 pm
The decision to wait until Monday to publish the rest of the photos and videos is mind blowing. There are all these articles out there right now about the successful test. If SNC published everything immediately, then all of those articles would have the video  embedded. You can't rely on the average person to check back a few days later. WOW THEM WHILE YOU CAN!!!
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Rocket Science on 11/12/2017 06:08 pm
The decision to wait until Monday to publish the rest of the photos and videos is mind blowing. There are all these articles out there right now about the successful test. If SNC published everything immediately, then all of those articles would have the video  embedded. You can't rely on the average person to check back a few days later. WOW THEM WHILE YOU CAN!!!
I noticed that the photos say "Credit: NASA" when they were first released. I wonder if this is the "hand of NASA" at play here in how it is going to be presented to the public?
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Rocket Science on 11/12/2017 06:13 pm
I don't recall if we ever got an orbital test flight target date, anyone? They had one under the Commercial Crew which I presumed will be utilized for this later flight...
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: JAFO on 11/12/2017 06:25 pm
The decision to wait until Monday to publish the rest of the photos and videos is mind blowing. There are all these articles out there right now about the successful test. If SNC published everything immediately, then all of those articles would have the video  embedded. You can't rely on the average person to check back a few days later. WOW THEM WHILE YOU CAN!!!

Naw, I disagree on that now that they've whetted our appetite. I'm sure they got videos/photos right away to the movers and shakers who matter (if they weren't being livestreamed to them), now they deserve a day off to watch some football, sleep in, analyze the data, etc.

Monday morning they can have a presser, and it will go right out to the morning shows, be a nice distraction from the politics they normally show. Can't wait.


Hope the presser will be streamed.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: yg1968 on 11/12/2017 07:35 pm
Dream Chaser's only customer at the moment is NASA.
False.

They also have the UN as a customer.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: woods170 on 11/13/2017 06:56 am
Dream Chaser's only customer at the moment is NASA.
False.

They also have the UN as a customer.

As well as a solid working relationship with DLR (not so much a customer): http://www.dlr.de/dlr/en/desktopdefault.aspx/tabid-10081/151_read-24422/#/gallery/28631

Quote from: DLR
DLR and the Sierra Nevada Corporation cooperate on low Earth orbit missions

DLR and the Sierra Nevada Corporation (SNC) signed a Memorandum of Understanding on 28 September 2017 to continue their 2013 cooperation on the use of the Dream Chaser. The two organisations plan to expand their joint engineering and scientific work to low Earth orbit applications as well. The cooperation is intended to produce concepts, conduct studies and jointly identify suitable technologies for future infrastructures for the period beyond the International Space Station (ISS). The Memorandum of Understanding was signed by Pascale Ehrenfreund, Chair of the DLR Executive Board, Professor Hansjörg Dittus, Member of the DLR Executive Board for Space Research and Technology, and Mark Sirangelo, Corporate Vice President at Sierra Nevada Corporation's Space Systems.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: JAFO on 11/13/2017 05:43 pm
Thanks to Rich Wilkes of the NASM  for taking the photo.




(you might be a space geek if....)
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Michael Baylor on 11/13/2017 07:16 pm
They also have the UN as a customer.
Yes, that's true. I forgot about that. However, my point still remains. No NASA = no Dream Chaser. I am not saying that's a problem. It is certainly true for many others as well, it just would be nice if the tax payers got more coverage of what they are paying for.

Anyways, hopefully there will end up being a good amount of commercial opportunities for Dream Chaser in the future!
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Michael Baylor on 11/13/2017 07:22 pm
The decision to wait until Monday to publish the rest of the photos and videos is mind blowing. There are all these articles out there right now about the successful test. If SNC published everything immediately, then all of those articles would have the video  embedded. You can't rely on the average person to check back a few days later. WOW THEM WHILE YOU CAN!!!

Naw, I disagree on that now that they've whetted our appetite. I'm sure they got videos/photos right away to the movers and shakers who matter (if they weren't being livestreamed to them), now they deserve a day off to watch some football, sleep in, analyze the data, etc.

Monday morning they can have a presser, and it will go right out to the morning shows, be a nice distraction from the politics they normally show. Can't wait.


Hope the presser will be streamed.
I would have potentially agreed with you if they came out swinging this morning. But, in classic SNC fashion we are still waiting.

Therefore, I am standing by my original point. While they may have given the space community enough, this article from the Verge was published today. There is one photo of the Dream Chaser actually flying, and it is from quite far away. I don't see any evidence into why this strategy would be good PR. Most of the general public has never heard of Dream Chaser. After reading that article they will likely forget about it. Have a video of the actual test, that would make things more memorable.

https://www.theverge.com/2017/11/13/16643094/sierra-nevada-corporation-dream-chaser-nasa-commercial-cargo-program-free-flight
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Rocket Science on 11/13/2017 08:31 pm
Thanks to Rich Wilkes of the NASM  for taking the photo.




(you might be a space geek if....)
Congratulations, it's a baby girl... :)
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: adrianwyard on 11/13/2017 08:43 pm
Left landing gear looks a bit twitchy at 2m01s. Aggressive ABS maybe?

https://twitter.com/sierranevcorp/status/930180794428952576

https://vimeo.com/242615668
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Rocket Science on 11/13/2017 08:59 pm
Going from memory, the previous test touchdown was at 161 Knots and this was 166 Knots... Do we have an exact landing weight?
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Rocket Science on 11/13/2017 09:11 pm
Left landing gear looks a bit twitchy at 2m01s. Aggressive ABS maybe?

https://twitter.com/sierranevcorp/status/930180794428952576

https://vimeo.com/242615668
Looked like a max braking test so more than likely the other gear looked the same if viewed. Concrete runways can be rough. She tracked straight from the video angle we see.  Slight bounce... The carbon nose gear skid shoe doing its job well...
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: rayleighscatter on 11/13/2017 09:24 pm
She tracked straight from the video angle we see. 

A little to the right perhaps. It lands on the dark marks in the middle of the runway but when wheels stop it is off to the right of those marks a little.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Rocket Science on 11/13/2017 09:33 pm
She tracked straight from the video angle we see. 

A little to the right perhaps. It lands on the dark marks in the middle of the runway but when wheels stop it is off to the right of those marks a little.
Could be at the end of the roll... I was trying to reference the runway markings. I'm sure they have other video angles...
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: rayleighscatter on 11/13/2017 09:38 pm
She tracked straight from the video angle we see. 

A little to the right perhaps. It lands on the dark marks in the middle of the runway but when wheels stop it is off to the right of those marks a little.
Could be at the end of the roll... I was trying to reference the runway markings. I'm sure they have other video angles...

Yeah, a somewhat perpendicular angle isn't the best for judging it.

I also noticed about 1:30 the center stabilizer had a bit of flutter, and it was over a bit right before that. It was calm before and after that though, a bit of crosswind at that altitude maybe? 
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Jeff Lerner on 11/13/2017 09:40 pm
Wow....that was some ride down...seemed to drop from its test altitude to 400 ft.  and gear deploy quite quickly...I would imagine they're going to want to soften that front skid strut somewhat...a bounce like that  with some wind blowing down the runway would make for a sporty landing...
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: adrianwyard on 11/13/2017 09:45 pm
She tracked straight from the video angle we see. 

A little to the right perhaps. It lands on the dark marks in the middle of the runway but when wheels stop it is off to the right of those marks a little.
Could be at the end of the roll... I was trying to reference the runway markings. I'm sure they have other video angles...

Yeah, a somewhat perpendicular angle isn't the best for judging it.

I also noticed about 1:30 the center stabilizer had a bit of flutter, and it was over a bit right before that. It was calm before and after that though, a bit of crosswind at that altitude maybe?

I noticed that too, looked like really random movement. But that could be the 'PTI' tests that are mentioned? I remember (from 2013?) someone from SNC describing how they have devised a way to exercise the avionics and flight controls with only a few flights, so perhaps this is what we're seeing. When the PTI tests conclude the stabilizer becomes much more, um... stable.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Rocket Science on 11/13/2017 09:45 pm
She tracked straight from the video angle we see. 

A little to the right perhaps. It lands on the dark marks in the middle of the runway but when wheels stop it is off to the right of those marks a little.
Could be at the end of the roll... I was trying to reference the runway markings. I'm sure they have other video angles...

Yeah, a somewhat perpendicular angle isn't the best for judging it.

I also noticed about 1:30 the center stabilizer had a bit of flutter, and it was over a bit right before that. It was calm before and after that though, a bit of crosswind at that altitude maybe?
I went to the update thread photo for a photo from the other side to indicate what you said. At low speed and if you get off the brakes she will diverge a bit till wheels stop with no nose gear steering. My impression was the rudder was getting a work-out and doing it's thing... Could be going through some turbulence or some kick tests...
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Lee Jay on 11/13/2017 09:48 pm
She tracked straight from the video angle we see. 

A little to the right perhaps. It lands on the dark marks in the middle of the runway but when wheels stop it is off to the right of those marks a little.

Hmmm..

The line shown is 70 feet right of the center line.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Rocket Science on 11/13/2017 09:49 pm
She tracked straight from the video angle we see. 

A little to the right perhaps. It lands on the dark marks in the middle of the runway but when wheels stop it is off to the right of those marks a little.

Hmmm..
Good enough for me!! ;D
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: JAFO on 11/13/2017 10:06 pm
She tracked straight from the video angle we see. 

A little to the right perhaps. It lands on the dark marks in the middle of the runway but when wheels stop it is off to the right of those marks a little.

Hmmm..

The line shown is 70 feet right of the center line.

Even though I knew the test was successful when I saw the dust kicking up from the nose skid I thought "Oh S$@@#%..... Where are the runway remaining signs at Eddy?"


That's why we test. Looked awesome. Worth waiting for. (I'll bet Steve Lindsey is going "*pfft.* I would have kept her on centerline all the way to wheel stop.")

Congrats, SNC!!!!
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Rocket Science on 11/13/2017 10:08 pm
Do we know how much if any runway camber there is at Edwards? Up to 5% by ICAO standards for transverse gradient for drainage...
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Rocket Science on 11/13/2017 10:10 pm
She tracked straight from the video angle we see. 

A little to the right perhaps. It lands on the dark marks in the middle of the runway but when wheels stop it is off to the right of those marks a little.

Hmmm..

The line shown is 70 feet right of the center line.

Even though I knew the test was successful when I saw the dust kicking up from the nose skid I thought "Oh S$@@#%..... Where are the runway remaining signs at Eddy?"


That's why we test. Looked awesome. Worth waiting for. I'll bet Steve Lindsey is going "*pfft.* I would have kept her on centerline all the way to wheel stop."

Congrats, SNC!!!!
Kicking-up some dust... ;)
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Michael Baylor on 11/13/2017 10:19 pm
Quote
Join us tomorrow at 4 p.m. MT for a live free-flight Q&A.

https://twitter.com/SierraNevCorp/status/930209924713508864
YES! This is exactly what SNC needs to be doing. I have been critical of them, so I must give credit where credit is do.

Good move!
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Lee Jay on 11/13/2017 10:21 pm
She tracked straight from the video angle we see. 

A little to the right perhaps. It lands on the dark marks in the middle of the runway but when wheels stop it is off to the right of those marks a little.

Hmmm..

The line shown is 70 feet right of the center line.

Even though I knew the test was successful when I saw the dust kicking up from the nose skid I thought "Oh S$@@#%..... Where are the runway remaining signs at Eddy?"


That's why we test. Looked awesome. Worth waiting for. I'll bet Steve Lindsey is going "*pfft.* I would have kept her on centerline all the way to wheel stop."

Congrats, SNC!!!!
Kicking-up some dust... ;)

Heh!

Just to be clear, this line is well inside the runway boundaries.  The runway is 300 feet wide (150 feet each side of the center line).
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Rocket Science on 11/13/2017 10:28 pm
She tracked straight from the video angle we see. 

A little to the right perhaps. It lands on the dark marks in the middle of the runway but when wheels stop it is off to the right of those marks a little.

Hmmm..

The line shown is 70 feet right of the center line.

Even though I knew the test was successful when I saw the dust kicking up from the nose skid I thought "Oh S$@@#%..... Where are the runway remaining signs at Eddy?"


That's why we test. Looked awesome. Worth waiting for. I'll bet Steve Lindsey is going "*pfft.* I would have kept her on centerline all the way to wheel stop."

Congrats, SNC!!!!
Kicking-up some dust... ;)

Heh!

Just to be clear, this line is well inside the runway boundaries.  The runway is 300 feet wide (150 feet each side of the center line).
Great pic LeeJay, those are the painted markings that I was referring to on either side which are a better reference than the rubber which is inconsistent...
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: rayleighscatter on 11/13/2017 10:32 pm
She tracked straight from the video angle we see. 

A little to the right perhaps. It lands on the dark marks in the middle of the runway but when wheels stop it is off to the right of those marks a little.

Hmmm..

The line shown is 70 feet right of the center line.

Even though I knew the test was successful when I saw the dust kicking up from the nose skid I thought "Oh S$@@#%..... Where are the runway remaining signs at Eddy?"


That's why we test. Looked awesome. Worth waiting for. I'll bet Steve Lindsey is going "*pfft.* I would have kept her on centerline all the way to wheel stop."

Congrats, SNC!!!!
Kicking-up some dust... ;)

Heh!

Just to be clear, this line is well inside the runway boundaries.  The runway is 300 feet wide (150 feet each side of the center line).

It's a relatively easier fix too, most of the divergence was the later portion of landing so just tweak the differential braking a bit. Easy to test too, I bet a tow test would take care of it.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Rocket Science on 11/13/2017 10:42 pm
I wouldn't worry about it... If that runway has some camber and there was a slight cross wind component or gust it would explain it. They have the data and it will speak for itself...
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: JAFO on 11/13/2017 11:06 pm
A little centerline deviation is a lot better than a PIO!!!

https://www.youtube.com/watch?v=DDkfFkNHqpE
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Kansan52 on 11/13/2017 11:20 pm
Just looks great from this armchair.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Rocket Science on 11/14/2017 12:56 am
A little centerline deviation is a lot better than a PIO!!!

Computers just don't experience that "pucker-factor"... ;)
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: JAFO on 11/14/2017 12:57 am
We feel the same way.

(https://www.sncorp.com/media/2337/afrc2017-0302-238.jpg)

(https://www.sncorp.com/media/2333/afrc2017-0302-236.jpg)


Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: JAFO on 11/14/2017 01:03 am
Graphic... but nice! 8)

Yeah, I figured they were 'shopped so I removed them.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: avollhar on 11/14/2017 12:29 pm

I also noticed about 1:30 the center stabilizer had a bit of flutter, and it was over a bit right before that. It was calm before and after that though, a bit of crosswind at that altitude maybe?

I noticed that too, looked like really random movement. But that could be the 'PTI' tests that are mentioned? I remember (from 2013?) someone from SNC describing how they have devised a way to exercise the avionics and flight controls with only a few flights, so perhaps this is what we're seeing. When the PTI tests conclude the stabilizer becomes much more, um... stable.

Very likely. PTI = Programmed Test Input. Just to compare to an excerpt from a Ares-IX slide:
"Programmed test inputs (PTI) injected during certain portions of powered flight to excite dynamics of interest"

If you remove 'powered' from this sentence, everything makes very much sense. What you typically do is to excite some modes (oscillations) and check if they are dampened (amplitude decreases) or not (bad day..). Hence the 'wobbly' appearance. Certainly simulated before the ALT but you should always validate your models.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: punder on 11/14/2017 12:42 pm
Uh oh... based on those photos I can just see Keith, over at that other website, firing up another rant on the lack of women in the space business.   ;)
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Rocket Science on 11/14/2017 01:10 pm

I also noticed about 1:30 the center stabilizer had a bit of flutter, and it was over a bit right before that. It was calm before and after that though, a bit of crosswind at that altitude maybe?

I noticed that too, looked like really random movement. But that could be the 'PTI' tests that are mentioned? I remember (from 2013?) someone from SNC describing how they have devised a way to exercise the avionics and flight controls with only a few flights, so perhaps this is what we're seeing. When the PTI tests conclude the stabilizer becomes much more, um... stable.

Very likely. PTI = Programmed Test Input. Just to compare to an excerpt from a Ares-IX slide:
"Programmed test inputs (PTI) injected during certain portions of powered flight to excite dynamics of interest"

If you remove 'powered' from this sentence, everything makes very much sense. What you typically do is to excite some modes (oscillations) and check if they are dampened (amplitude decreases) or not (bad day..). Hence the 'wobbly' appearance. Certainly simulated before the ALT but you should always validate your models.
Agreed, during X-15 test flights it was normal to do "rudder-kicks" in that case by the pilot...
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: rayleighscatter on 11/14/2017 11:01 pm

I also noticed about 1:30 the center stabilizer had a bit of flutter, and it was over a bit right before that. It was calm before and after that though, a bit of crosswind at that altitude maybe?

I noticed that too, looked like really random movement. But that could be the 'PTI' tests that are mentioned? I remember (from 2013?) someone from SNC describing how they have devised a way to exercise the avionics and flight controls with only a few flights, so perhaps this is what we're seeing. When the PTI tests conclude the stabilizer becomes much more, um... stable.

Very likely. PTI = Programmed Test Input. Just to compare to an excerpt from a Ares-IX slide:
"Programmed test inputs (PTI) injected during certain portions of powered flight to excite dynamics of interest"

If you remove 'powered' from this sentence, everything makes very much sense. What you typically do is to excite some modes (oscillations) and check if they are dampened (amplitude decreases) or not (bad day..). Hence the 'wobbly' appearance. Certainly simulated before the ALT but you should always validate your models.

Spot on! From SNC's twitter.
Quote
That 'wobbling' was actually an intentional 'Programmed Test Input', or PTI. This set of maneuvers was designed to assess the responsiveness and stability of the vehicle and provide us better aerodynamic data. Worked Great!!
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: adrianwyard on 11/14/2017 11:32 pm
The Twitter Q&A with SNC's Steve Lindsey answered quite a few questions posted recently:

https://twitter.com/hashtag/askthedreamteam?src=hash

I asked what thruster propellants would be used, but other than confirming they are non-toxic no info was provided. Am I correct in saying SNC have never disclosed any specs for the cargo version propulsion? Isn't that a little weird? Details such as propellants and suppliers must have been decided long ago. Surely the basics can't be proprietary info? Has anyone heard any details I may have missed?
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Prettz on 11/15/2017 03:30 am
Is the cargo version propulsion (RCS) not going to be the same as what the crew version was to have? Why would there be any need to change it?
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: adrianwyard on 11/15/2017 03:56 am
I imagine so! But that doesn't help because IIRC SNC never stated what the RCS would be on the crewed version :-)

Edit to add: When SNC bought Orbitec it was possible to wonder if Dream Chaser would gain some technology from that heritage, i.e. Methane-Nitrous or Propane-Nitrous. But this was always just a guess.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: yg1968 on 11/15/2017 01:50 pm
The Twitter Q&A with SNC's Steve Lindsey answered quite a few questions posted recently:

https://twitter.com/hashtag/askthedreamteam?src=hash

I asked what thruster propellants would be used, but other than confirming they are non-toxic no info was provided. Am I correct in saying SNC have never disclosed any specs for the cargo version propulsion? Isn't that a little weird? Details such as propellants and suppliers must have been decided long ago. Surely the basics can't be proprietary info? Has anyone heard any details I may have missed?

We know that the thrusters it will be furnished by their former Wisconsin subsidiary, Orbitec. There was some information on their (former) website which was also posted on the thread below. But yes, you are right, SNC has been very secretive about the propellant being used.

https://forum.nasaspaceflight.com/index.php?topic=38801.0

Quote
ORBITEC Expands Vortex Rocket Engine Family with Successful Demonstration of New Propellants

MADISON, Wis. (Nov. 10, 2015) – Sierra Nevada Corporation’s (SNC) wholly-owned subsidiary Orbital Technologies Corporation (ORBITEC) recently completed successful testing and demonstration of three different propellant combinations for its existing 30,000-pound thrust vortex rocket engine. [...]

These tests demonstrate the ability to transition use of different propellant combinations in the same core rocket engine design with slight changes to accommodate a specific combination of fuel and oxidizer, including propane and kerosene fuels with nitrous oxide (laughing gas) and liquid oxygen oxidizers.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: AlexP on 11/15/2017 02:34 pm
They were using ethanol for RCS back in 2011

https://www.youtube.com/watch?v=D7sWtEAddkM

(Question at ~37:10)
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: vt_hokie on 11/15/2017 03:35 pm
Is that HL-20 mockup still at SNC?
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Rocket Science on 11/15/2017 04:18 pm
They were using ethanol for RCS back in 2011

https://www.youtube.com/watch?v=D7sWtEAddkM

(Question at ~37:10)
I recall some jokes back then that there will be some "happy" ground crews servicing the vehicle... ;D
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Rocket Science on 11/15/2017 04:23 pm
Is that HL-20 mockup still at SNC?
AFAIK, maybe LeeJay can confirm...
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: adrianwyard on 11/15/2017 04:46 pm
They were using ethanol for RCS back in 2011

https://www.youtube.com/watch?v=D7sWtEAddkM

(Question at ~37:10)
I recall some jokes back then that there will be some "happy" ground crews servicing the vehicle... ;D

Moreso if the oxidizer is Nitrous! (which is a reasonable guess) :-) :-)
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: whitelancer64 on 11/15/2017 05:04 pm
Is that HL-20 mockup still at SNC?
AFAIK, maybe LeeJay can confirm...

There's a DreamChaser mockup on display at the Wings Over the Rockies Air & Space Museum. https://wingsmuseum.org/portfolio/dream-chaser/

My google-fu doesn't seem to be able to find where the HL-20 mockup built at LaRC is now.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: sanman on 11/15/2017 05:15 pm
So the nosegear seemed to bounce after the initial touchdown - is that nominal, or is it something they may tweak to get rid of in the future?

Did they have mass-simulators for human passengers inside there?
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Cherokee43v6 on 11/15/2017 05:28 pm
Is that HL-20 mockup still at SNC?
AFAIK, maybe LeeJay can confirm...

There's a DreamChaser mockup on display at the Wings Over the Rockies Air & Space Museum. https://wingsmuseum.org/portfolio/dream-chaser/

My google-fu doesn't seem to be able to find where the HL-20 mockup built at LaRC is now.

As someone who was a student at NC State in 1990, in looking at the placard in front of the mockup, I'd say that there is a very good chance that this is the same mockup that NSCU's Aerospace Engineering students built in partnership with NC A&T and NASA. 

The primary purpose of the mockup wasn't for the exterior mold-line, but for the study of the human factors elements in designing and utilizing that shape's interior.  The left-hand image is possibly a picture taken of the HL-20 mockup on the NSCU 'Brickyard' from one of the upper floors of the DH Hill library (you can just see hints of the yellow zig-zag pattern in the ground around the ship).  The right hand image is one that was published at the time as an illustration of a possible interior layout to demonstrate the purpose of the mockup.

One way to tell for sure, does anyone know what a Piper Navajo's landing gear looks like?  The gear under the mockup is supposed to be from one.

http://www.wral.com/spacecraft-with-nc-roots-successfully-tested/17113929/

note that the image within this article looks very much like the image from the previous link.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Rocket Science on 11/15/2017 06:43 pm
Is that HL-20 mockup still at SNC?
AFAIK, maybe LeeJay can confirm...

There's a DreamChaser mockup on display at the Wings Over the Rockies Air & Space Museum. https://wingsmuseum.org/portfolio/dream-chaser/

My google-fu doesn't seem to be able to find where the HL-20 mockup built at LaRC is now.
Nice find, that looks to be her! :)
https://www.nasa.gov/centers/langley/news/factsheets/HL-20.html
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Ronsmytheiii on 11/15/2017 07:01 pm
Is that HL-20 mockup still at SNC?
AFAIK, maybe LeeJay can confirm...

There's a DreamChaser mockup on display at the Wings Over the Rockies Air & Space Museum. https://wingsmuseum.org/portfolio/dream-chaser/

My google-fu doesn't seem to be able to find where the HL-20 mockup built at LaRC is now.
Nice find, that looks to be her! :)
https://www.nasa.gov/centers/langley/news/factsheets/HL-20.html

Hey, that belongs at the Virginia Air & Space Center , give it back!
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: JAFO on 11/15/2017 07:20 pm
Good writeup in the NY Times

https://www.nytimes.com/2017/11/13/science/dream-chaser-test-flight.html
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: catdlr on 11/16/2017 03:04 am
SNC released a shorter version of the video.

Dream Chaser Free Flight Test 2017: Shortened

SNCspacesystems
Published on Nov 15, 2017

Sierra Nevada Corporation's (SNC) Dream Chaser® spacecraft had a successful free-flight test on November 11, 2017, at Edwards Air Force Base, with the support of NASA's Armstrong Flight Research Center.

https://youtu.be/AWrLzfpM_8A?t=001

https://youtu.be/AWrLzfpM_8A
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: catdlr on 11/16/2017 03:06 am
SNC also re-released the original long version.

Dream Chaser Free Flight Test 2017


SNCspacesystems
Published on Nov 15, 2017


Sierra Nevada Corporation's (SNC) Dream Chaser® spacecraft had a successful free-flight test on November 11, 2017, at Edwards Air Force Base, with the support of NASA's Armstrong Flight Research Center.

https://youtu.be/aDEKSPOLXAc?t=001

https://youtu.be/aDEKSPOLXAc

Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: penguin44 on 11/16/2017 06:41 am
Left landing gear looks a bit twitchy at 2m01s. Aggressive ABS maybe?

https://twitter.com/sierranevcorp/status/930180794428952576

https://vimeo.com/242615668

I thought it was my eyes, but I looked again and saw not only the wheel but the door cover flutter as well.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: CameronD on 11/16/2017 09:34 pm
Amongst the other real photos at https://www.sncorp.com/news-resources/media-resources/ (https://www.sncorp.com/news-resources/media-resources/), I was amused to see that the "Dream Chaser Cockpit Flight Simulator" pic is merely a wire-frame CAD render of a cockpit simulator with p'shopped Garmin G1000 sim pics dropped in for good measure.  (A simulation of a simulator?) 

The pic is a few years old.. haven't they built a real cockpit simulator yet?
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: envy887 on 11/17/2017 03:08 am
Amongst the other real photos at https://www.sncorp.com/news-resources/media-resources/ (https://www.sncorp.com/news-resources/media-resources/), I was amused to see that the "Dream Chaser Cockpit Flight Simulator" pic is merely a wire-frame CAD render of a cockpit simulator with p'shopped Garmin G1000 sim pics dropped in for good measure.  (A simulation of a simulator?) 

The pic is a few years old.. haven't they built a real cockpit simulator yet?

If you're referring to this picture:
https://www.sncorp.com/media/1937/sncs-dream-chaser-cockpit-flight-simulator.png

That's not a render. There are a ton of details that nobody would bother to model or texture, such as crooked cuts in the paneling, 3M tape used to hold the glass panels on, and dirt smudges on the black center panel.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: CameronD on 11/17/2017 05:39 am
Amongst the other real photos at https://www.sncorp.com/news-resources/media-resources/ (https://www.sncorp.com/news-resources/media-resources/), I was amused to see that the "Dream Chaser Cockpit Flight Simulator" pic is merely a wire-frame CAD render of a cockpit simulator with p'shopped Garmin G1000 sim pics dropped in for good measure.  (A simulation of a simulator?) 

The pic is a few years old.. haven't they built a real cockpit simulator yet?

If you're referring to this picture:
https://www.sncorp.com/media/1937/sncs-dream-chaser-cockpit-flight-simulator.png

That's not a render. There are a ton of details that nobody would bother to model or texture, such as crooked cuts in the paneling, 3M tape used to hold the glass panels on, and dirt smudges on the black center panel.

Ok.. my bad.  Maybe there's not enough resolution on my monitor to pick those fine details up.  :(

..but if it's a real simulator, why the modified G1000 sim views on what are, presumably, touchscreens?  No real software yet??
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Rocket Science on 11/17/2017 03:33 pm
Amongst the other real photos at https://www.sncorp.com/news-resources/media-resources/ (https://www.sncorp.com/news-resources/media-resources/), I was amused to see that the "Dream Chaser Cockpit Flight Simulator" pic is merely a wire-frame CAD render of a cockpit simulator with p'shopped Garmin G1000 sim pics dropped in for good measure.  (A simulation of a simulator?) 

The pic is a few years old.. haven't they built a real cockpit simulator yet?

If you're referring to this picture:
https://www.sncorp.com/media/1937/sncs-dream-chaser-cockpit-flight-simulator.png

That's not a render. There are a ton of details that nobody would bother to model or texture, such as crooked cuts in the paneling, 3M tape used to hold the glass panels on, and dirt smudges on the black center panel.

Ok.. my bad.  Maybe there's not enough resolution on my monitor to pick those fine details up.  :(

..but if it's a real simulator, why the modified G1000 sim views on what are, presumably, touchscreens?  No real software yet??
Draper...
http://www.draper.com/news/making-commercial-space-flight-more-accessible
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: penguin44 on 11/18/2017 06:59 am
Yup not a render, you can totally see the side of the photographers head in shadow.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: rayleighscatter on 11/18/2017 02:50 pm
DC trying to thumb a ride from a passing SRB?
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Ronsmytheiii on 11/19/2017 11:10 am
DC trying to thumb a ride from a passing SRB?



That is one of the SRBs that was displayed at KSC with the mockup shuttle Explorer stack at the Visitors center. When that area was redeveloped for The Atlantis building, the California Science Center had the two SRBs from the display (believe they are a mix of real components and mock ups) moved to NASA Armstrong for the eventual full stack Endeavour exhibit. Eventually, Orbital ATK donated a full flight hardware SRB set to the museum, so they are redundant and will stay there for the time being.

Edit: One was donated to the Pima Air and Space Museum in Tucson, Arizona
http://www.collectspace.com/news/news-122916a-pima-air-space-museum-rocket-booster.html
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Rocket Science on 11/19/2017 06:54 pm
I've been thinking about the final wheels stop position of Dream Chaser since the test. She tracked straight under hard braking with no problems and only veered right at the end of the roll-out. Was this possibly a test to steer clear off an active runway? The claim is that she can land at any airport that can handle a 737... Just musing...
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: CameronD on 11/19/2017 09:28 pm
I've been thinking about the final wheels stop position of Dream Chaser since the test. She tracked straight under hard braking with no problems and only veered right at the end of the roll-out. Was this possibly a test to steer clear off an active runway? The claim is that she can land at any airport that can handle a 737... Just musing...

If it's related to the apparent left wheel shimmy at all then, just possibly... brake fade.

And it's for this reason I'm not sure you'd want to steer an unpowered vehicle off of a straight line trajectory (eg. onto a taxiway after the landing roll), because, sans nose-wheel, it's not guaranteed that you'd make the turn.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: adrianwyard on 11/19/2017 09:53 pm
Both are plausible. I doubt a strong crosswind was a factor this time, but without nose steering could it be somewhat susceptible to getting blown off the centerline as the speed drops?
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: CameronD on 11/19/2017 10:05 pm
Both are plausible. I doubt a strong crosswind was a factor this time, but without nose steering could it be somewhat susceptible to getting blown off the centerline as the speed drops?

Potentially.. but at the quoted landing speed of 191 miles per hour, it would need to be a gusty crosswind to have any noticeable effect.

Asymmetric brake fade will be a bigger deal.. because with no brakes on one side, they can't steer at low speed - but no doubt they'll be taking appropriate precautions to prevent that.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Rocket Science on 11/19/2017 11:25 pm
I've been thinking about the final wheels stop position of Dream Chaser since the test. She tracked straight under hard braking with no problems and only veered right at the end of the roll-out. Was this possibly a test to steer clear off an active runway? The claim is that she can land at any airport that can handle a 737... Just musing...

If it's related to the apparent left wheel shimmy at all then, just possibly... brake fade.

And it's for this reason I'm not sure you'd want to steer an unpowered vehicle off of a straight line trajectory (eg. onto a taxiway after the landing roll), because, sans nose-wheel, it's not guaranteed that you'd make the turn.
Agreed... I've never landed anything with a nose skid and two wheeled gear so I'm a bit uncertain how it would handle a turn with the drag on the skid and differential braking on one side to turn. Like I said just musing if this was part of the test with their wish to land at airports anywhere and not tie up the runway.  Would be nice to get a definitive answer though...
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: CameronD on 11/20/2017 12:14 am
I've been thinking about the final wheels stop position of Dream Chaser since the test. She tracked straight under hard braking with no problems and only veered right at the end of the roll-out. Was this possibly a test to steer clear off an active runway? The claim is that she can land at any airport that can handle a 737... Just musing...

If it's related to the apparent left wheel shimmy at all then, just possibly... brake fade.

And it's for this reason I'm not sure you'd want to steer an unpowered vehicle off of a straight line trajectory (eg. onto a taxiway after the landing roll), because, sans nose-wheel, it's not guaranteed that you'd make the turn.
Agreed... I've never landed anything with a nose skid and two wheeled gear so I'm a bit uncertain how it would handle a turn with the drag on the skid and differential braking on one side to turn. Like I said just musing if this was part of the test with their wish to land at airports anywhere and not tie up the runway.  Would be nice to get a definitive answer though...

Sure... From what we've seen it sure seems they would be able to land at any airport that can handle a 737.

Even with a nose skid, they'd need not tie up the runway for more than a couple of minutes if they had their tow vehicle standing by.  Hook on the tow-bar/dolly, brakes off and away they go...in less time than it would take a following aircraft to go around.

This last landing test is impressive on more than a few counts.  :)
 
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Rocket Science on 11/20/2017 01:14 am
I've been thinking about the final wheels stop position of Dream Chaser since the test. She tracked straight under hard braking with no problems and only veered right at the end of the roll-out. Was this possibly a test to steer clear off an active runway? The claim is that she can land at any airport that can handle a 737... Just musing...

If it's related to the apparent left wheel shimmy at all then, just possibly... brake fade.

And it's for this reason I'm not sure you'd want to steer an unpowered vehicle off of a straight line trajectory (eg. onto a taxiway after the landing roll), because, sans nose-wheel, it's not guaranteed that you'd make the turn.
Agreed... I've never landed anything with a nose skid and two wheeled gear so I'm a bit uncertain how it would handle a turn with the drag on the skid and differential braking on one side to turn. Like I said just musing if this was part of the test with their wish to land at airports anywhere and not tie up the runway.  Would be nice to get a definitive answer though...

Sure... From what we've seen it sure seems they would be able to land at any airport that can handle a 737.

Even with a nose skid, they'd need not tie up the runway for more than a couple of minutes if they had their tow vehicle standing by.  Hook on the tow-bar/dolly, brakes off and away they go...in less time than it would take a following aircraft to go around.

This last landing test is impressive on more than a few counts.  :)
It was well worth the wait to be sure... Note to ground crew "don't forget to wear your oven mitts"... ;D
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: CameronD on 11/20/2017 02:45 am
It was well worth the wait to be sure... Note to ground crew "don't forget to wear your oven mitts"... ;D

ROTFLOL!! (You made me spill my coffee..)  ;D ;D
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: yg1968 on 01/21/2018 02:34 am
It's not recent but I found this presentation on DC which is good:

http://ndiatvc.org/images/downloads/SMDWG_July_2016/ndia_space___missile_defense_wg_18_jul_16_vfinal2.pdf

Among other things, it states the following:

Quote
Mature Vehicle with All Major Risks Retired

-Hot fired ORBITEC Vortex engine propulsion system numerous times
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Alpha Control on 01/21/2018 05:22 am
It's not recent but I found this presentation on DC which is good:

http://ndiatvc.org/images/downloads/SMDWG_July_2016/ndia_space___missile_defense_wg_18_jul_16_vfinal2.pdf

Among other things, it states the following:

Quote
Mature Vehicle with All Major Risks Retired

-Hot fired ORBITEC Vortex engine propulsion system numerous times

Thanks YG. I hadn't seen this before. Among the slides (some of which had very good graphics of Crew DC & Cargo DC), I caught that same thing you did, about the Orbitec Vortec engine testing (slide 19). 

I confess I'm not clear at this point - is Cargo DC using Orbitec Vortec engines for the RCS role? Or are they for the OMS role? (orbit adjustment/deorbit)?  Or none of the above?
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: yg1968 on 01/22/2018 12:13 am
Both, it seems. Orbitec was already doing the RCS prior to SNC aquiring them.

Quote
SNC has been working with ORBITEC for over three years. ORBITEC is the lead for the Environmental Control and Life Support Systems (ECLSS) and Thermal Control Systems (TCS) for SNC, providing reliable living conditions including temperature and humidity control to support the astronauts during their journeys on SNC's Dream Chaser® spacecraft. Recently, SNC selected ORBITEC to provide the RCS engines for Dream Chaser using green, nontoxic propellants. The flexibility of fuel and oxidizer options along with the ability to quickly scale engine size makes ORBITEC's Vortex technology the growing industry preferred choice for Reaction Control Systems (RCS), Upper Stage engines and potentially boost class engines.

https://www.sncorp.com/press-releases/snc-orbitec-acquisition/

Quote
Orbitec will produce the environmental control system that handles air and heat inside the Dream Chaser and rocket engine thrusters that will propel and steer the vehicle in space, Zamprelli said.

http://host.madison.com/wsj/business/orbitec-to-fly-high-in-sierra-nevada-s-dream-chaser/article_3b9aa641-e3ce-5d7e-8ead-da4908bd2c30.html
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Rocket Science on 02/07/2018 10:13 pm
Thank you for the great article gents and congrats on your first John! :)   Seems like we have turned a corner and momentum is beginning to build. Heady days for commercial space all around! 8)
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: JohnR on 02/07/2018 10:24 pm
Thank you for the great article gents and congrats on your first John! :)

Thank you for the kind words!
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Norm38 on 02/07/2018 11:21 pm
Very cool to hear this is flying to ISS soon.  I'd still love to see this architecuture combined with the 2nd stage to increase reuse, but baby steps.  But this is great to have.  If we can't have propulsive landings, I'll take a runway landing over ocean splashdowns.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: northenarc on 02/08/2018 01:19 am
  Well, welcome to the ISS club. They can always lower expectations for the first Dream Chaser landings by taking only trash back and calling them 'experimental' like SpaceX does for their boosters. Lifting bodies just make me a little nervous, maybe because I can't help thinking of The Six Million Dollar Man intro whenever I see the thing.  :o   
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Rocket Science on 02/08/2018 01:23 am
Can someone please refresh my memory (yeah, I'm old) on the main gear utilized on ALT-2 and source info. On  ALT-1 I know the F-5 gear was hydraulic and contamination caused the failure. On ALT-2 was it the same F-5 main gear only with electrical actuators? If I remember the plan for the orbital vehicle that the gear will be electrically actuated and will have bespoke main gear, not the F-5 as in ALT-2 correct?
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Lobo on 02/08/2018 05:00 pm
It looks like DC will now have folding wings to fit into the Atlas PLF (this may have happened awhile ago, I haven't been following DC very closely for awhile).

And will fly on Atlas with 5 SRB's and a new modified Centaur with two RL-10's.

Seems like it'd almost make more sense to move the LV to Falcon 9, as that's a more LEO optimized LV than Atlas-Centaur.  No upper stage modifications required, it's just a much higher thrust upper stage.  It'd probably have to fly in expendable configuration, but obviously Atlas does anyway.

I wonder how far along ULA is in development of the 2-engine Centaur?  The investment may have already been spent so it may be too late to switch horses now.  Just seems like the Falcon is a more optimized LV for DC's needs, given it's thrust and propellant types than Atlas which is more optimized for payloads going beyond LEO with it's low thrust/high efficiency Centaur upper stage.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: PahTo on 02/08/2018 05:07 pm

I wonder how far along ULA is in development of the 2-engine Centaur?  The investment may have already been spent so it may be too late to switch horses now.  Just seems like the Falcon is a more optimized LV for DC's needs, given it's thrust and propellant types than Atlas which is more optimized for payloads going beyond LEO with it's low thrust/high efficiency Centaur upper stage.

Note the 2-engine Centaur (in the contemporary form, for lack of a better term) has been in development to support CST Starliner, so DC is not the only customer/reason.  Beyond that, Centaur 5 is the ultimate design path for ULA upper stage development wrt Centaur, leading to ACES, but now we're getting ahead of ourselves...
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: DaveS on 02/08/2018 05:12 pm
It looks like DC will now have folding wings to fit into the Atlas PLF (this may have happened awhile ago, I haven't been following DC very closely for awhile).

And will fly on Atlas with 5 SRB's and a new modified Centaur with two RL-10's.

Seems like it'd almost make more sense to move the LV to Falcon 9, as that's a more LEO optimized LV than Atlas-Centaur.  No upper stage modifications required, it's just a much higher thrust upper stage.  It'd probably have to fly in expendable configuration, but obviously Atlas does anyway.

I wonder how far along ULA is in development of the 2-engine Centaur?  The investment may have already been spent so it may be too late to switch horses now.  Just seems like the Falcon is a more optimized LV for DC's needs, given it's thrust and propellant types than Atlas which is more optimized for payloads going beyond LEO with it's low thrust/high efficiency Centaur upper stage.
The original Centaur featured twin RL-10's (called Dual Engine Centaur). The Single Engine Centaur (SEC) was only introduced with the Atlas V. So SEC is the modification, not the DEC.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Coastal Ron on 02/08/2018 05:42 pm
Seems like it'd almost make more sense to move the LV to Falcon 9, as that's a more LEO optimized LV than Atlas-Centaur.  No upper stage modifications required, it's just a much higher thrust upper stage.  It'd probably have to fly in expendable configuration, but obviously Atlas does anyway.

Not sure you've heard, but if a reusable Falcon 9 is not powerful enough for your needs, SpaceX now has a reusable launch vehicle called Falcon Heavy that can likely take care of your needs...  ;)

However I'm sure Sierra Nevada knows what their launch vehicle options are, and for whatever good reasons they have they have determined that Atlas V is their best choice. Which is fine with me, because I'm more interested in getting Dream Chaser into space than who takes them there!

Fingers crossed for my favorite LEO spacecraft to stay on schedule...
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: rayleighscatter on 02/08/2018 08:36 pm
It looks like DC will now have folding wings to fit into the Atlas PLF (this may have happened awhile ago, I haven't been following DC very closely for awhile).

And will fly on Atlas with 5 SRB's and a new modified Centaur with two RL-10's.

Seems like it'd almost make more sense to move the LV to Falcon 9, as that's a more LEO optimized LV than Atlas-Centaur.  No upper stage modifications required, it's just a much higher thrust upper stage.  It'd probably have to fly in expendable configuration, but obviously Atlas does anyway.

I wonder how far along ULA is in development of the 2-engine Centaur?  The investment may have already been spent so it may be too late to switch horses now.  Just seems like the Falcon is a more optimized LV for DC's needs, given it's thrust and propellant types than Atlas which is more optimized for payloads going beyond LEO with it's low thrust/high efficiency Centaur upper stage.

I believe DC wouldn't fit inside Falcon's fairing.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Lobo on 02/08/2018 09:50 pm

I believe DC wouldn't fit inside Falcon's fairing.

I think both the Atlas 5m and Falcon PLF's are about the same diameter?
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Lobo on 02/08/2018 09:57 pm
Seems like it'd almost make more sense to move the LV to Falcon 9, as that's a more LEO optimized LV than Atlas-Centaur.  No upper stage modifications required, it's just a much higher thrust upper stage.  It'd probably have to fly in expendable configuration, but obviously Atlas does anyway.

Not sure you've heard, but if a reusable Falcon 9 is not powerful enough for your needs, SpaceX now has a reusable launch vehicle called Falcon Heavy that can likely take care of your needs...  ;)

However I'm sure Sierra Nevada knows what their launch vehicle options are, and for whatever good reasons they have they have determined that Atlas V is their best choice. Which is fine with me, because I'm more interested in getting Dream Chaser into space than who takes them there!

Fingers crossed for my favorite LEO spacecraft to stay on schedule...
Falcon Heavy?

Never heard of it...

 ;D

Yea, there's that.  I was just trying to keep things a little more apples-to-apples.
Although, what's the LEO capacity of the FH with a recovered center core, to the ISS inclination?  If you can't recover the center core, then no reason to use it vs. the single stick F9 I wouldn't think?

But yea, all your points are valid and I agree.  Things are progressing and I'm sure connections and calculations are all being made for the Atlas LV and there'd be a certain amount of backtracking to switch LV's.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: JAFO on 02/09/2018 12:23 am
Ok, I'm confused. Will her first orbital flight be the demo to the ISS, or are they planning another orbital "flight to nowhere" without an ISS rendezvous to test her out? 
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Rocket Science on 02/09/2018 12:26 am
Ok, I'm confused. Will her first orbital flight be the demo to the ISS, or are they planning another orbital "flight to nowhere" without an ISS rendezvous to test her out?
My impression is the one flight cleared to ISS... Unless I'm confused as well! ;D
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: rayleighscatter on 02/09/2018 02:25 pm

I believe DC wouldn't fit inside Falcon's fairing.

I think both the Atlas 5m and Falcon PLF's are about the same diameter?

I believe it was the length, not the diameter that was the limiting factor.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Rocket Science on 02/09/2018 02:29 pm
From woods170 in the update thread:

"Between the 2013 and 2017 tests, a number of systems have changed on the Dream Chaser ETA including the main gear that is more advanced than that flown on the first test and is closer to the flight hardware. The ETA was also flying with upgraded space-rated avionics and flight software that will be used on operational Dream Chaser missions to the Space Station."

Bold mine:
To me it still looks like the F-5E main gear... Now what "advanced and closer" means is not actual final final flight hardware which is to be built by Triumphgroup... But thanks just the same... :)

BTW I own a 1969 Triumph GT6 produced by the wonderful craftsmen of the British car industry... What became of them?? :(
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: CameronD on 02/11/2018 09:55 pm
BTW I own a 1969 Triumph GT6 produced by the wonderful craftsmen of the British car industry... What became of them?? :(

It's complicated.. but in summary: after joining forces with several other small British marques (British Leyland), following many decades of fighting for survival they were conquered by the Germans (BMW) and the rest, as they say, is history.  ;D
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Star One on 04/16/2018 04:00 pm
Why Sierra Nevada’s owners are betting big on Dream Chaser

Quote
To Fatih and Eren Ozmen, Dream Chaser is more than a spaceplane. It’s a vehicle to transform the entire industry.

Some highlights for me from the interview.

Talking about launchers for DC.

Quote
Eren: We also will be selecting the launch vehicle for future missions. We are working with many launch providers and they are coming up with very affordable new launch vehicles in the 2021 timeframe. After the first mission, we will have more opportunities to reduce the cost because a significant cost of our mission is the launch. We are looking at all those different partnerships with different companies, looking for synergies and strategic relationships. We are in very heavy discussions with all of them. That is helping us understand how the dynamics are changing and how to maintain our competitive place while launch costs come down and technology improves.

Talking about crewed DC.

Quote
Eren: Yes. The NASA crew contract that we got awarded is still open. And actually, we got an extension on that contract. There is no current funding right now because two other companies [Boeing and SpaceX] got the award. But the reason we didn’t get the crew contract is because supposedly we couldn’t achieve the schedule. Now you see the other two companies are behind schedule.

How they are paying for it all.

Quote
Eren: Yes. The NASA crew contract that we got awarded is still open. And actually, we got an extension on that contract. There is no current funding right now because two other companies [Boeing and SpaceX] got the award. But the reason we didn’t get the crew contract is because supposedly we couldn’t achieve the schedule. Now you see the other two companies are behind schedule.

What makes DC unique.

Quote
Fatih: A key discriminator between Dream Chaser and our competitors is that we are the only rocket-agnostic space vehicle. We are not married to any particular program.

With Dream Chaser, we have a lot of partnerships internationally. We have applications across the board, from the United Nations to working with pharmaceutical companies.

It is a unique approach that is different than what we’ve been doing for the last 40-50 years: sending capsules into space and bringing them back to splash down in the ocean. Dream Chaser lands like the space shuttle did and it leverages all the lessons learned over the years into a next-generation spaceplane.

http://spacenews.com/why-sierra-nevadas-owners-are-betting-big-on-dream-chaser/
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: TrevorMonty on 04/16/2018 06:41 pm
Fatih: Dream Chaser doesn’t have to go up, it can come down. We can do an in-space crew version. It doesn’t have to be the same as what Boeing and SpaceX are doing today.

Eren: Actually, Dream Chaser was a rescue vehicle initially.

I could see one radical option, launch DC and Starliner together on NG. Have DC inside fairing and crew in Starliner on top of fairing, much same way SLS is being designed to launch crew and cargo.

Once in space crew have lot of living space between DC plus its cargo pod/airlock and Starliner. Crew can return in either vehicle or split crew sending some back early in Starliner. This could work for combined commercial astronuats + tourist flight. Have 4 tourists stay for a week then send them back in Starliner, 2 crew stay on for a month or two.

Crew can return in DC or wait for next Starliner or Dragon.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: yg1968 on 04/16/2018 06:49 pm
The following parts of the interview are interesting:

Quote from: Ozmens
Fatih: We are going through a series of critical design reviews right now. We have a contract in place to do the first launch in 2020. That’s the next big milestone.

Eren: We also will be selecting the launch vehicle for future missions. We are working with many launch providers and they are coming up with very affordable new launch vehicles in the 2021 timeframe. After the first mission, we will have more opportunities to reduce the cost because a significant cost of our mission is the launch. We are looking at all those different partnerships with different companies, looking for synergies and strategic relationships. We are in very heavy discussions with all of them. That is helping us understand how the dynamics are changing and how to maintain our competitive place while launch costs come down and technology improves.

Quote from: Fatih Ozmen
That’s where we look at Blue Origin, Jeff Bezos’ kind of vision. That’s when we talked to him about making space accessible and millions of people going to space, doing experiments, finding the next-generation solutions and making Earth more green, moving heavy industry up there. All these ideas from mining an asteroid to finding new habitats for humanity and making Earth a better place are symbolized in this one vehicle.

SNC says that it hasn't chosen its LV beyond the first mission. It would be interesting to see a partnership between Blue and SNC.

P.S. However, there may have been some confusion here because SNC has already ordered two Atlas V missions from ULA. So I think that they meant after the first (two) mission(s) and not just the first mission. 

https://www.ulalaunch.com/about/news/2017/07/19/united-launch-alliance-signs-contract-with-sierra-nevada-corporation-to-launch-dream-chaser-spacecraft-to-deliver-cargo-to-international-space-station
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: TrevorMonty on 04/19/2018 02:00 am
Also considering European (A6?)and Japanese LVs (H3?).

He noted that there are no requirements under its NASA contract that require those cargo missions to fly on U.S. vehicles, citing NASA’s use of European and Japanese cargo vehicles to resupply the ISS. “We think it’s certainly feasible,” he said, adding that there was interest in launching Dream Chaser on vehicles outside the U.S.

Can see  ESA supplying A6 for there private DC missions, not sure about UN mission. ESA may offer A6 for ISS resupply missions in exchange for more access to ISS.

While DC is not LV depended it still costs a bit to match it to LV, would need a few flights to make it worthwhile.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: woods170 on 04/19/2018 06:49 am
Also considering European (A6?)and Japanese LVs (H3?).

He noted that there are no requirements under its NASA contract that require those cargo missions to fly on U.S. vehicles, citing NASA’s use of European and Japanese cargo vehicles to resupply the ISS. “We think it’s certainly feasible,” he said, adding that there was interest in launching Dream Chaser on vehicles outside the U.S.

Can see  ESA supplying A6 for there private DC missions, not sure about UN mission. ESA may offer A6 for ISS resupply missions in exchange for more access to ISS.

While DC is not LV depended it still costs a bit to match it to LV, would need a few flights to make it worthwhile.


Wrong. DC basically behaves like any other other unmanned payload. All that is needed to launch it on A6 is a right-sized payload adapter. The cost of a launch is, for the most part, not in the adapter.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: su27k on 04/19/2018 07:22 am
He noted that there are no requirements under its NASA contract that require those cargo missions to fly on U.S. vehicles, citing NASA’s use of European and Japanese cargo vehicles to resupply the ISS.

I find this hard to believe, I think Orbital had to certify Antares contains enough US components to qualify as US launch vehicle when signing CRS1 contract. European and Japanese provided cargo vehicle in exchange for NASA sending their astronauts to ISS, I don't see how that is comparable to this situation.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: rayleighscatter on 04/19/2018 09:10 pm
He noted that there are no requirements under its NASA contract that require those cargo missions to fly on U.S. vehicles, citing NASA’s use of European and Japanese cargo vehicles to resupply the ISS.

I find this hard to believe, I think Orbital had to certify Antares contains enough US components to qualify as US launch vehicle when signing CRS1 contract. European and Japanese provided cargo vehicle in exchange for NASA sending their astronauts to ISS, I don't see how that is comparable to this situation.

Requirements changed between CRS 1 & 2. This may have been one of the changes. One can only assume that if SNC is spending the money to investigate foreign launch providers, that it must be possible.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: deruch on 04/20/2018 02:13 am
Can see  ESA supplying A6 for there private DC missions, not sure about UN mission. ESA may offer A6 for ISS resupply missions in exchange for more access to ISS.

That's not at all a possibility.  NASA and the CRS providers class these missions as pure commercial launches.  In fact, the companies themselves are the launch customers and NASA is only the customer for the cargo.  So, assuming the CRS2 contract doesn't explicitly require the use of a US launch vehicle, SNC could purchase a ride on A6 for Dream Chaser, but it would be a straight cash purchase with no in-kind swap between agencies. 
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: woods170 on 04/20/2018 07:22 am
He noted that there are no requirements under its NASA contract that require those cargo missions to fly on U.S. vehicles, citing NASA’s use of European and Japanese cargo vehicles to resupply the ISS.

I find this hard to believe, I think Orbital had to certify Antares contains enough US components to qualify as US launch vehicle when signing CRS1 contract. European and Japanese provided cargo vehicle in exchange for NASA sending their astronauts to ISS, I don't see how that is comparable to this situation.

Requirements changed between CRS 1 & 2. This may have been one of the changes. One can only assume that if SNC is spending the money to investigate foreign launch providers, that it must be possible.

I can tell you, based on source information, that your bolded IS in fact one of the changes.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: brickmack on 04/20/2018 07:40 pm
He noted that there are no requirements under its NASA contract that require those cargo missions to fly on U.S. vehicles, citing NASA’s use of European and Japanese cargo vehicles to resupply the ISS.

I find this hard to believe, I think Orbital had to certify Antares contains enough US components to qualify as US launch vehicle when signing CRS1 contract. European and Japanese provided cargo vehicle in exchange for NASA sending their astronauts to ISS, I don't see how that is comparable to this situation.

Considering that the reverse was bid for COTS and CRS1 (putting either HTV or ATV or Progress, or some derivative thereof, on an American launcher), it seems hard to believe that this wouldn't be an option
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: JAFO on 04/22/2018 03:53 am
I thought the OTA had been under construction at Michoud in a JV with LM for a few years? Was that the Crew DC, maybe, and it was changed after missing the upselect?
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: rayleighscatter on 04/29/2018 01:05 am
A little surprising about possibly only a single flight vehicle being built since there isn't much (relative) cost in building a second craft. Although I also wouldn't be surprised for a second one to be built through whatever means.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Rocket Science on 04/29/2018 12:02 pm
Just musing about the topic of a second DC and since Mark always wanted a crewed vehicle and he could be building all the spares required up to the point where the vehicle could be either a cargo or crew version, lets say an 80% commonality point. Then depending on requirements SNC could construct the remaining components of whichever variant was wanted crew or cargo depending on the "space-landscape" at the time in the future which has a lot of uncertainty at this point with new political and LV/SC (Bigelow station?) players in the mix...
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Patchouli on 04/30/2018 05:52 am
Just musing about the topic of a second DC and since Mark always wanted a crewed vehicle and he could be building all the spares required up to the point where the vehicle could be either a cargo or crew version, lets say an 80% commonality point. Then depending on requirements SNC could construct the remaining components of whichever variant was wanted crew or cargo depending on the "space-landscape" at the time in the future which has a lot of uncertainty at this point with new political and LV/SC (Bigelow station?) players in the mix...

The crewed DC seemed fairly far along so I would not be surprised if the cargo variant had 80% or more commonality.

A lifting body or space plane does have several advantages over a ballistic reentry vehicle for tourism and medical evacuations.
Cross range,low g reentry,a proven safe landing mode,and lands close to civilization.


Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: yg1968 on 04/30/2018 02:02 pm
There is 85% commonality between cargo and crewed version of DC according to SNC:

Quote from: Jeff Foust
Lindsey: crew version of Dream Chaser “very much alive,” with 85% commonality between systems in cargo and crew versions.

https://twitter.com/jeff_foust/status/688067187257556993
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: rayleighscatter on 04/30/2018 09:08 pm
Just musing about the topic of a second DC and since Mark always wanted a crewed vehicle and he could be building all the spares required up to the point where the vehicle could be either a cargo or crew version, lets say an 80% commonality point. Then depending on requirements SNC could construct the remaining components of whichever variant was wanted crew or cargo depending on the "space-landscape" at the time in the future which has a lot of uncertainty at this point with new political and LV/SC (Bigelow station?) players in the mix...

Interesting thought. I wonder if it would be possible to build a cargo craft that has some of the requirements for crew built in (windows, etc.) and in such a way that the remaining features can still be built in at a later date (ECLSS, crew accommodations & interface, etc.)

It would take a hit in upmass (mass certainly, some volume likely as well) but would be well positioned to be able to sell services to non-CRS clients.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Cherokee43v6 on 04/30/2018 09:28 pm
Also considering European (A6?)and Japanese LVs (H3?).

He noted that there are no requirements under its NASA contract that require those cargo missions to fly on U.S. vehicles, citing NASA’s use of European and Japanese cargo vehicles to resupply the ISS. “We think it’s certainly feasible,” he said, adding that there was interest in launching Dream Chaser on vehicles outside the U.S.

Can see  ESA supplying A6 for there private DC missions, not sure about UN mission. ESA may offer A6 for ISS resupply missions in exchange for more access to ISS.

While DC is not LV depended it still costs a bit to match it to LV, would need a few flights to make it worthwhile.

A lot of people seem to be reading this as 'Sierra Nevada' owns the DC launched on the foreign rocket.  I, however, read this more as a 'sales ploy'. 

"So, ESA/JAXA wants its own astronaut launch capability?  Here, buy a couple DCs from us, they'll work on your launcher with just a little fine tuning." 

"Hey Virgin Galactic.  Why spend all that money developing SS-3 in-house when we have a perfectly viable system to put in your hands."
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: brickmack on 05/01/2018 01:04 am
Interesting thought. I wonder if it would be possible to build a cargo craft that has some of the requirements for crew built in (windows, etc.) and in such a way that the remaining features can still be built in at a later date (ECLSS, crew accommodations & interface, etc.)

It would take a hit in upmass (mass certainly, some volume likely as well) but would be well positioned to be able to sell services to non-CRS clients.

Technically it should be easy, but it probably wouldn't be very useful. With fixed-position wings it can't fit in a fairing, meaning it can't carry the expendable module. Without that, pressurized volume drops by like half and it loses unpressurized capacity entirely, plus the scheduling benefit of being able to do IDS or CBM attachment. With the main launch options all being fully or mostly expendable, it seems difficult for such a craft to compete against the other CRS systems with such a drop in capability. It'd still need at least an AV N32 most likely, judging by the crew variant (less densely packed I assume) needing 2 boosters and 2 RL10s. Cygnus has over two times the pressurized volume, but requires no boosters and only 1 RL10 (~25-30 million dollars savings). And folding wings (even if deployed at liftoff, without a fairing) are likely a hard no for NASA crew missions
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Rocket Science on 05/01/2018 05:03 pm
Interesting thought. I wonder if it would be possible to build a cargo craft that has some of the requirements for crew built in (windows, etc.) and in such a way that the remaining features can still be built in at a later date (ECLSS, crew accommodations & interface, etc.)

It would take a hit in upmass (mass certainly, some volume likely as well) but would be well positioned to be able to sell services to non-CRS clients.

Technically it should be easy, but it probably wouldn't be very useful. With fixed-position wings it can't fit in a fairing, meaning it can't carry the expendable module. Without that, pressurized volume drops by like half and it loses unpressurized capacity entirely, plus the scheduling benefit of being able to do IDS or CBM attachment. With the main launch options all being fully or mostly expendable, it seems difficult for such a craft to compete against the other CRS systems with such a drop in capability. It'd still need at least an AV N32 most likely, judging by the crew variant (less densely packed I assume) needing 2 boosters and 2 RL10s. Cygnus has over two times the pressurized volume, but requires no boosters and only 1 RL10 (~25-30 million dollars savings). And folding wings (even if deployed at liftoff, without a fairing) are likely a hard no for NASA crew missions
They would just go back to the original "fixed winglet" DC without a cargo module, an adapter plus abort engines for crewed flights or even back to the HL-20 adapter with SRMS for abort...
https://forum.nasaspaceflight.com/index.php?topic=29126.20
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Patchouli on 05/01/2018 09:39 pm


Technically it should be easy, but it probably wouldn't be very useful. With fixed-position wings it can't fit in a fairing, meaning it can't carry the expendable module. Without that, pressurized volume drops by like half and it loses unpressurized capacity entirely, plus the scheduling benefit of being able to do IDS or CBM attachment. With the main launch options all being fully or mostly expendable, it seems difficult for such a craft to compete against the other CRS systems with such a drop in capability. It'd still need at least an AV N32 most likely, judging by the crew variant (less densely packed I assume) needing 2 boosters and 2 RL10s. Cygnus has over two times the pressurized volume, but requires no boosters and only 1 RL10 (~25-30 million dollars savings). And folding wings (even if deployed at liftoff, without a fairing) are likely a hard no for NASA crew missions
They would just go back to the original "fixed winglet" DC without a cargo module, an adapter plus abort engines for crewed flights or even back to the HL-20 adapter with SRMS for abort...
https://forum.nasaspaceflight.com/index.php?topic=29126.20
[/quote]

With New Glenn they probably can use SRMs for abort without any worries about it having an impact on payload.
Since it's stages are 7M wide the bending loads probably would be much less of an issue.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: john smith 19 on 05/07/2018 08:05 am
A lot of people seem to be reading this as 'Sierra Nevada' owns the DC launched on the foreign rocket.  I, however, read this more as a 'sales ploy'. 

"So, ESA/JAXA wants its own astronaut launch capability?  Here, buy a couple DCs from us, they'll work on your launcher with just a little fine tuning." 

"Hey Virgin Galactic.  Why spend all that money developing SS-3 in-house when we have a perfectly viable system to put in your hands."
I think you have this backward.

SNC have a part of the CTS II contract.  It would make sense for them to investigate if other LV's can launch it cheaper than the current Atlas V baseline.

Obviously launching to the ISS is a nice reference mission for both Arianespace and (IIRC) Mitsubishi Heavy Industries to add to their portfolio for potential customers.

But AFAIK SNC would be buying those flights on their own. They would be the customer.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: brickmack on 06/03/2018 05:33 am
I gotta wonder though, why is DC apparently having so much more success on this than DragonLab? Dragon already exists and is flying routinely, offers comparable downmass/volume capacity and more unpressurized up capacity, and its probably significantly cheaper since F9 is cheaper than Atlas or Ariane and its trunk is simpler than Dream Chaser's equivalent. Yet SpaceX advertised DragonLab flights for years, and apparently never got any serious interest
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Star One on 06/03/2018 11:47 am
I gotta wonder though, why is DC apparently having so much more success on this than DragonLab? Dragon already exists and is flying routinely, offers comparable downmass/volume capacity and more unpressurized up capacity, and its probably significantly cheaper since F9 is cheaper than Atlas or Ariane and its trunk is simpler than Dream Chaser's equivalent. Yet SpaceX advertised DragonLab flights for years, and apparently never got any serious interest

You seem to be making a heck of a lot of assumptions here in multiple areas. For a start I very much doubt that Dragon offers a comparable downmass/volume capacity for the simple fact that DC is intending to fulfil its cargo commitments with less flights than Dragon is.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: SweetWater on 06/03/2018 12:57 pm
I gotta wonder though, why is DC apparently having so much more success on this than DragonLab? Dragon already exists and is flying routinely, offers comparable downmass/volume capacity and more unpressurized up capacity, and its probably significantly cheaper since F9 is cheaper than Atlas or Ariane and its trunk is simpler than Dream Chaser's equivalent. Yet SpaceX advertised DragonLab flights for years, and apparently never got any serious interest

We don't know how serious the interest in flying experiments on Dream Chaser is from any of these ~150 parties is - just that they have apparently expressed interest.

DragonLab got at least as far as SpaceX manifesting flights http://www.spacex.com/press/2012/12/19/spacex-adds-two-dragonlabtm-missions-manifest (http://www.spacex.com/press/2012/12/19/spacex-adds-two-dragonlabtm-missions-manifest) The press release is from December of 2008, about 18 months from when Falcon 9 first flew. I don't think they ever released who their customers were or why those flights were canceled.

Don't get me wrong - I'd like to see Dream Chaser succeed, and the interest alone is encouraging for Sierra Nevada. But right now there's just a tweet.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: yg1968 on 06/03/2018 02:32 pm
I gotta wonder though, why is DC apparently having so much more success on this than DragonLab? Dragon already exists and is flying routinely, offers comparable downmass/volume capacity and more unpressurized up capacity, and its probably significantly cheaper since F9 is cheaper than Atlas or Ariane and its trunk is simpler than Dream Chaser's equivalent. Yet SpaceX advertised DragonLab flights for years, and apparently never got any serious interest

DC will only be using an Atlas V for its first flight. SNC has hinted that Blue Origin could be an option for its other flights to the ISS.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: gongora on 06/03/2018 05:09 pm
I gotta wonder though, why is DC apparently having so much more success on this than DragonLab? Dragon already exists and is flying routinely, offers comparable downmass/volume capacity and more unpressurized up capacity, and its probably significantly cheaper since F9 is cheaper than Atlas or Ariane and its trunk is simpler than Dream Chaser's equivalent. Yet SpaceX advertised DragonLab flights for years, and apparently never got any serious interest

DC has one possible governmental organization sponsored cargo mission they're talking about.  That's not really much more success than DragonLab.

You seem to be making a heck of a lot of assumptions here in multiple areas. For a start I very much doubt that Dragon offers a comparable downmass/volume capacity for the simple fact that DC is intending to fulfil its cargo commitments with less flights than Dragon is.

DC can do fewer flights because it has a larger upmass volume, thanks to the expendable pressurized module they're using on the back of DC.

We don't know how serious the interest in flying experiments on Dream Chaser is from any of these ~150 parties is - just that they have apparently expressed interest.

DragonLab got at least as far as SpaceX manifesting flights http://www.spacex.com/press/2012/12/19/spacex-adds-two-dragonlabtm-missions-manifest (http://www.spacex.com/press/2012/12/19/spacex-adds-two-dragonlabtm-missions-manifest) The press release is from December of 2008, about 18 months from when Falcon 9 first flew. I don't think they ever released who their customers were or why those flights were canceled.

Don't get me wrong - I'd like to see Dream Chaser succeed, and the interest alone is encouraging for Sierra Nevada. But right now there's just a tweet.

There's no private sector interest in flying any of these vehicles at realistic mission prices.  I think you're making a bad assumption about SpaceX ever having customers for DragonLab.  I think they put notional missions on the manifest as advertising for the capability.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: rayleighscatter on 06/03/2018 08:46 pm

There's no private sector interest in flying any of these vehicles at realistic mission prices.

Hit a big nail on the head there. It's no secret that the Russian half of ISS has much less science to do compared to the US half, mostly owing to funding. If there were good commercial demand for space science the Russians would be selling their excess capabilities, and much cheaper than any dedicated launch.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: deruch on 06/06/2018 07:12 pm
I gotta wonder though, why is DC apparently having so much more success on this than DragonLab? Dragon already exists and is flying routinely, offers comparable downmass/volume capacity and more unpressurized up capacity, and its probably significantly cheaper since F9 is cheaper than Atlas or Ariane and its trunk is simpler than Dream Chaser's equivalent. Yet SpaceX advertised DragonLab flights for years, and apparently never got any serious interest

I also think one of the big draws is that DC can be landed on a runway in other countries.  So, at least 1 participant country will get to have the vehicle landed in their territory.  That's a much more visible and higher profile demonstration of space activity for local consumption.  Additionally, maybe SNC just came up with a better business model?  IIRC, SpaceX was mainly trying to interest businesses or more individual research orgs.  By going through the UN, maybe SNC has gotten more interest.  The question will be how much money is there in that market?  Will funding be limited to a one-off?  Or will there be enough continuing interest, combined with available funding, to run multiple missions?
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: IW1DGG on 06/26/2018 10:17 am
DC4EU
I found this interesting presentation available on internet about DC4EU on Ariane-6. It seems that ArianeGroup is seriously working on this.

http://www.essc.esf.org/fileadmin/user_upload/essc/2017-11-23_ESSC_Dream_Chaser_for_European_Utilisation.pdf

(http://i66.tinypic.com/302xh7r.jpg)
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Joseph Peterson on 07/13/2018 10:29 pm
Article focused on Erin Ozmen.  I didn't notice anything new about Dream Chaser.  That said, I found it to be an interesting read.

https://www.forbes.com/sites/forbesdigitalcovers/2018/07/11/meet-the-unknown-immigrant-billionaire-betting-her-fortune-to-take-on-musk-in-space/
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: TripleSeven on 07/13/2018 10:47 pm


Hit a big nail on the head there. It's no secret that the Russian half of ISS has much less science to do compared to the US half, mostly owing to funding. If there were good commercial demand for space science the Russians would be selling their excess capabilities, and much cheaper than any dedicated launch.

you are in my view probably correct in that there is not a lot of....non government "commercial demand" for space science.

but I doubt really that even if there were the Russian segment would get the business. 

doing business with the Russians on their part of the space station is 1) very expensive and 2) very complicated in terms of dealing with the Russians.  plus, and this is being kind, the results on the Russian side are very well my words are "less rigorous" than what you get on the US/other side

micro gravity research is the great white whale of space flight...but at some point I predict the science and engineering with catch and harpoon this whale and someone is going to make some serious money with it

it wont be on the Russian side. 
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: fast on 04/08/2019 07:29 am
Why cargo module is conical and not cylindrical shape?

 
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: b0objunior on 04/08/2019 07:42 am
Why cargo module is conical and not cylindrical shape?

Larger base = more stable.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: ncb1397 on 04/08/2019 07:45 am
Why cargo module is conical and not cylindrical shape?

Larger base = more stable.

I think it would have more to do with the interface with the spaceplane has footprint limits while the cargo module has to maximize volume.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: b0objunior on 04/08/2019 07:47 am
Why cargo module is conical and not cylindrical shape?

Larger base = more stable.

I think it would have more to do with the interface with the spaceplane has footprint limits while the cargo module has to maximize volume.
Also
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: wings_no_capsules on 04/08/2019 07:37 pm
hey...anyone got a pic of what the crewed DC would look like?

Also is the crewed variant dead? how long would it take to outfit a cargo DC for a crew?
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Chris Bergin on 04/08/2019 07:47 pm
hey...anyone got a pic of what the crewed DC would look like?

Also is the crewed variant dead? how long would it take to outfit a cargo DC for a crew?

Welcome to the site's forum. I knew you'd be posting here when I saw the username :)

Crewed Dream Chaser is sort of dead. Some potential private deal, but it's dead to NASA and thus no real funding.

Looked like this:

https://www.youtube.com/watch?v=niupPzdZa6M
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Prettz on 04/08/2019 08:32 pm
So the black parts on the bottom and the wings are the heavy-duty heatshielding, while on the top, the white parts represent increased protection and the black is lighter protection?

Also, it looks like it has shoe treads on the bottom now.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: adrianwyard on 04/09/2019 06:57 pm
Four years ago, shortly after Cargo Dream Chaser was revealed, we discussed how it appeared as if the aft thrusters would fire into the solar panels and/or other hardware.  The best guesses back then were that the graphics were inaccurate or the thrusters would not be used while attached to the cargo module, i.e. Dream Chaser would only fly backwards. (https://forum.nasaspaceflight.com/index.php?topic=37049.msg1347885#msg1347885).

But recent depictions (attached) seem to show the same problem. Furthermore, the aft pointing nozzles seem beefier than the others. So what's going on? Are the graphics and models still out of date? Or is it OK to plume the hardware behind you?

https://twitter.com/SierraNevCorp/status/1115637377299550208
https://twitter.com/SierraNevCorp/status/1115011424475127811





Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Steven Pietrobon on 04/10/2019 09:34 am
But recent depictions (attached) seem to show the same problem. Furthermore, the aft pointing nozzles seem beefier than the others. So what's going on?

I believe those thrusters are only used to de-orbit the vehicle, once the cargo module has been jettisoned. The lightweight cargo module will decay naturally and presumably completely burn up in the atmosphere.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: wings_no_capsules on 04/12/2019 02:08 pm
wonder if this has been posted

http://www.unoosa.org/documents/pdf/psa/activities/2017/GrazSymposium/presentations/Monday/Presentation12.pdf
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Nomadd on 04/12/2019 04:30 pm
wonder if this has been posted

http://www.unoosa.org/documents/pdf/psa/activities/2017/GrazSymposium/presentations/Monday/Presentation12.pdf

 "Only runway landing space vehicle in existence"

  Who's going to break the news to the X-34?
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: libra on 04/12/2019 04:44 pm
You mean the X-37 of course ;)
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Rocket Science on 04/12/2019 05:06 pm
You mean the X-37 of course ;)
And those Shuttles enjoying time in their retirement homes quietly reveling about their younger days... :)
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: birdman on 04/12/2019 05:16 pm
I wonder how the runway landings are actually going to work out once (if?) this thing starts flying. One of their selling points is "able to land at any runway able to handle large planes", but surely that would need the airport to at least partially shut down to process it and I don't think any big airports would want to do that. Landing at Air Force bases seems much more reasonable, and it's not like there's a big lack of those.

Sure would be cool to see it come screaming down the runway while you're waiting for your flight though!
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: DistantTemple on 04/13/2019 12:08 am
You mean the X-37 of course ;)
The two "in existence" are not available. Would Boeing build another for commercial use - on non-USA missions? Is it allowed to - isn't it secret tec? And doesn't it use Hypergolics... so more dangerous at landing, unlike DC.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: brickmack on 04/14/2019 01:22 am
Boeing has repeatedly proposed derivatives of X-37 for NASA or commercial use. ISS crew and cargo, freeflying labs, satellite servicing/recovery, etc. And their processing facility has room for like 6 X-37Bs.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: libra on 04/14/2019 04:36 pm
wonder if this has been posted

http://www.unoosa.org/documents/pdf/psa/activities/2017/GrazSymposium/presentations/Monday/Presentation12.pdf

Nice paper, interesting mission. Dang, the U.N entering the space race, sounds a bit like Star Trek...
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: bad_astra on 04/16/2019 06:54 pm
wonder if this has been posted

http://www.unoosa.org/documents/pdf/psa/activities/2017/GrazSymposium/presentations/Monday/Presentation12.pdf

Nice paper, interesting mission. Dang, the U.N entering the space race, sounds a bit like Star Trek...
UN has had a space exploration office since i think the late 1960's but it's never really done anything of note.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: envy887 on 08/14/2019 07:05 pm
Vulcan-Centaur was selected for Cargo Dream Chaser, in what Tory Bruno described as a very competitive launch market. While the market in general is no doubt competitve, how much choice did SNC really have here? From my understanding, Cargo Dream Chaser is over 18 tonnes launch mass. To ISS inclination, that restricts the current and soon-available options to:

Atlas V 552 / Vulcan-Centaur: the 552 is probably available as a backup if Vulcan isn't ready in time, but it's much more expensive. Vulcan is an obvious choice between the two.

Falcon Heavy recovered / Falcon 9 expended: Cargo Dream Chaser with the cargo pod is too long for the Falcon fairing, isn't it? The spaceplane itself is already 9 m long, and the cargo pod should push it past the Falcon fairing 11 meter internal length. SpaceX is working on a long fairing for NSSL Class C, but doesn't need that until 2025.

New Glenn: probably won't be ready for a commercial launch in 2021, definitely not in early 2021 and Blue has no backup vehicle to offer.

Omega XL: definitely won't be ready for a commercial launch in 2021, and the intermediate version is too small.

Ariane 5 ECA / Ariane 64: Can CRS launches launch from a foreign spaceport?

SuperHeavy/Starship: while russian nesting dolls spaceplanes would be awesome, banking on a 2021 commercial launch is a bit dubious and SpaceX can't offer a backup vehicle unless they extend the Falcon fairing.

The way I see it, it was either Vulcan/Atlas, wait until at least late 2021, convince SpaceX to offer a long fairing early on, or go overseas.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Rocket Science on 08/14/2019 07:12 pm
Excellent coverage LeeJay! 8)
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Tywin on 08/14/2019 07:12 pm
They talked, about the japanese rocket H3 too, I think so...

But yeah, the logical move, is selecting Vulcan, especially if in the future SNC sell the engines for the US of the Vulcan....
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Tywin on 08/14/2019 07:20 pm
The most interesting things I heard.

 - The cargo Dreamchaser still has the full suite of life support systems, and theoretically could be used to bring crew back to Earth in an emergency.

 - A Dreamchaser on Vulcan's SECOND flight. That seems like a major vote of confidence to me.

 - Thrusters can throttle to 3 different thrust levels.

 - SNC may be working on a RL-10 replacement?

And maybe most importantly:

 - It was repeatedly said that Vulcan was very competitively priced.

Indirectly Tory said, that the flight of the Vulcan could be in the very early of 2021...that means the BE-4 engines coming very good and in time too...
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Rocket Science on 08/14/2019 07:21 pm
RCS H2O2/RP1 prop...
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: TrevorMonty on 08/14/2019 07:30 pm
ULA isn't retiring Atlas till Vulcan has few flights so still option to switch to Atlas if issues with Vulcan.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: JEF_300 on 08/14/2019 07:36 pm
This wasn't totally clear to me; will there still be some sort of demonstration mission launched on an Atlas V, or will the first Dream chaser launch now be on Vulcan?
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Rocket Science on 08/14/2019 07:40 pm
This wasn't totally clear to me; will there still be some sort of demonstration mission launched on an Atlas V, or will the first Dream chaser launch now be on Vulcan?
I believe Tory said whichever LV was available to meet the early 2021 launch date and could be the second flight for Vulcan after first demo...
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Rocket Science on 08/14/2019 07:42 pm
Hope for Crew Drew Chaser lives on and development discussion continues! 8)
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: JEF_300 on 08/14/2019 08:00 pm
This wasn't totally clear to me; will there still be some sort of demonstration mission launched on an Atlas V, or will the first Dream chaser launch now be on Vulcan?
I believe Tory said whichever LV was available to meet the early 2021 launch date and could be the second flight for Vulcan after first demo...

Dreamchaser will launch in early 2021, on Vulcan if it's ready, and on Atlas if it's not, I get that. I just want to clarify absolutely that the early 2021 launch intended for Vulcan will be the first Dreamchaser launch, and that the previously agreed to Atlas V flights are no more.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Kansan52 on 08/14/2019 08:33 pm
Yes, 1st Dreamchaser launch.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Lars-J on 08/14/2019 09:43 pm
Vulcan with 4 SRBs... Huh.

How much is the lift-off mass of the Cargo DreamChaser?
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Thunderscreech on 08/14/2019 10:05 pm
Vulcan with 4 SRBs... Huh.

How much is the lift-off mass of the Cargo DreamChaser?
I don't know, but when they talked about it being launcher-agnostic a few years ago, they said Falcon Heavy vs. just Falcon 9 for the SpaceX option so...  not light.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Rocket Science on 08/14/2019 10:42 pm
Great to have a Dream Chaser article again Chris, thank you! 8)
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: abaddon on 08/15/2019 12:24 am
I know ULA is as reliable as they come, but it is interesting that SNC is willing to have DreamChaser launched on the second flight of a new launcher, considering they are planning on building only one DreamChaser.  Since it is a NASA flight it's not insured; I wonder if SNC will separately insure the spacecraft to protect them against possible LOV.

Definitely a vote of confidence in ULA, although there's of course a chance it will move to an Atlas V if ULA can't meet the schedule with Vulcan.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Lee Jay on 08/15/2019 12:41 am
Excellent coverage LeeJay! 8)

Thanks!

It sure is nice that my little way to support this amazing site is only 15 minutes from work and 15 minutes from home!
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: yg1968 on 08/15/2019 01:40 am
Excellent coverage LeeJay! 8)

Thanks!

It sure is nice that my little way to support this amazing site is only 15 minutes from work and 15 minutes from home!

Excellent questions especially the one about the RCS thrusters.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Prettz on 08/15/2019 02:10 am
Has anyone ever asked if Cargo DC can launch without the cargo pod? Not sure the usefulness of doing so, but I'm curious. They were developing that adapter for the crew version.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Steven Pietrobon on 08/15/2019 06:05 am
Dreamchaser will launch in early 2021, on Vulcan if it's ready, and on Atlas if it's not, I get that.

NSF article shows first Dreamchaser CRS mission (SNC-1) launching in September 2021.

https://www.nasaspaceflight.com/2019/08/cargo-dream-chaser-solidifies-ula-deal-vulcan/
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Rocket Science on 08/15/2019 08:34 am
Has anyone ever asked if Cargo DC can launch without the cargo pod? Not sure the usefulness of doing so, but I'm curious. They were developing that adapter for the crew version.
Along the lines of that question, I wish we had more info about the LAS for a Crewed Dream Chaser...
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: TrevorMonty on 08/15/2019 11:26 am
Has anyone ever asked if Cargo DC can launch without the cargo pod? Not sure the usefulness of doing so, but I'm curious. They were developing that adapter for the crew version.
Along the lines of that question, I wish we had more info about the LAS for a Crewed Dream Chaser...
Likely to be H202 + RP1 engines, something like SuperDraco egines.

Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: adrianwyard on 08/15/2019 06:06 pm
Yes it would be interesting to know what the LAS options are these days. The previous plan (using the on board hybrids) was not received well by reviewers during the commercial crew competition IIRC.

My guess is they'd add a pusher LAS to the stage adapter, rather than redo the plumbing in the vehicle itself. Something like the original plan for HL-20/42. (Picture here: http://www.astronautix.com/h/hl-42.html)

Whether they'd be solids, liquid, or even hybrids is anyone's guess.

More info on HL-20 abort here: https://www.researchgate.net/publication/24298984_Launch-pad_abort_capabilities_of_the_HL-20_lifting_body
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: TCizadlo on 08/15/2019 06:08 pm
From the Q&A, is it correct to understand that they use an H2O2/RP-1 mix for RCS?!  If so, that's bonkers, I wonder what the ignition system for it looks like.

Or did I misunderstand his answer to the question?
From my understanding, some H2O2/RP-1 systems can be implemented to be hypergolic. You basically decompose the peroxide in such a way it ignites, then feed in the RP-1 just after the peroxide catalyst so it burns with the extra oxygen in the elevated ambient conditions.

I would like to add to this that Kerosene-Peroxide is a return to form for the vehicle as the HL-20 program had selected a Kerosene-Peroxide OMS combined with a peroxide RCS. The biprop RCS makes sense for Dream Chaser as it lacks a dedicated OMS system, and thus the RCS jets might need a higher thrust capability.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Sesquipedalian on 08/15/2019 10:38 pm
I haven't seen anyone mention the contrast between the 5 SRBs on the Atlas V and the 4 SRBs on the Vulcan.  Is this because the BE-4s are more powerful than the RD-180s, or because the new SRB designs are more powerful than the old ones?  Or something else?
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: yg1968 on 08/15/2019 11:19 pm
This wasn't totally clear to me; will there still be some sort of demonstration mission launched on an Atlas V, or will the first Dream chaser launch now be on Vulcan?
I believe Tory said whichever LV was available to meet the early 2021 launch date and could be the second flight for Vulcan after first demo...

Vulcan is the baseline but they can switch to Atlas V if necessary (i.e. if Vulcan isn't ready). But he seemed confident that Vulcan should be ready by that time.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: envy887 on 08/15/2019 11:20 pm
I haven't seen anyone mention the contrast between the 5 SRBs on the Atlas V and the 4 SRBs on the Vulcan.  Is this because the BE-4s are more powerful than the RD-180s, or because the new SRB designs are more powerful than the old ones?  Or something else?

All of the above. Centaur V is also bigger.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: JEF_300 on 08/17/2019 12:57 am
Do we know how Dreamchaser is powered? Is there a fuel cell, or just batteries, or some other thing?
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Lee Jay on 08/17/2019 04:14 am
Do we know how Dreamchaser is powered? Is there a fuel cell, or just batteries, or some other thing?

Batteries and solar panels.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: JEF_300 on 08/17/2019 05:29 am
Do we know how Dreamchaser is powered? Is there a fuel cell, or just batteries, or some other thing?

Batteries and solar panels.

The crew version didn't/won't have the solar panels from the cargo module, right? Does it just rely on batteries?
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Rocket Science on 08/17/2019 03:22 pm
This wasn't totally clear to me; will there still be some sort of demonstration mission launched on an Atlas V, or will the first Dream chaser launch now be on Vulcan?
I believe Tory said whichever LV was available to meet the early 2021 launch date and could be the second flight for Vulcan after first demo...

Vulcan is the baseline but they can switch to Atlas V if necessary (i.e. if Vulcan isn't ready). But he seemed confident that Vulcan should be ready by that time.
I thought that was what I was saying yg, but clarifying is is fine and worth repeating I guess...
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Rocket Science on 08/17/2019 03:52 pm
Yes it would be interesting to know what the LAS options are these days. The previous plan (using the on board hybrids) was not received well by reviewers during the commercial crew competition IIRC.

My guess is they'd add a pusher LAS to the stage adapter, rather than redo the plumbing in the vehicle itself. Something like the original plan for HL-20/42. (Picture here: http://www.astronautix.com/h/hl-42.html)

Whether they'd be solids, liquid, or even hybrids is anyone's guess.

More info on HL-20 abort here: https://www.researchgate.net/publication/24298984_Launch-pad_abort_capabilities_of_the_HL-20_lifting_body
We talked (speculated) about this for so many years... ;D Now that they've gone to H2O2/RP1 my sense is that they may use  engines back in the same location as the old hybrid proposal. I really wished the question was asked and an official answer was given. Maybe we can poke them a bit for more info... ;)
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: adrianwyard on 08/17/2019 04:17 pm
I'm not quite up to the challenge but it would be possible to determine if there's sufficient available volume in Dream Chaser to house tanks large enough for abort - given its mass, the energy density and likely ISP of H2O2/RP1 engines.

I always liked the idea of being able to use the LAS as a pseudo third stage: that way it's exercised every flight, and you don't re-enter with the added propellant mass - or land with it on board.

I wonder if they'd fly the cargo module with the crew version. If so, adding LAS to that seems possible; we now know it has thrusters and presumably tanks. There'd be room under the fairing for larger tanks and engines. You'd need a way for DC to separate from the module during the abort.

Yes, DC has given us years of fun speculating!

Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Rocket Science on 08/17/2019 05:38 pm
I'm not quite up to the challenge but it would be possible to determine if there's sufficient available volume in Dream Chaser to house tanks large enough for abort - given its mass, the energy density and likely ISP of H2O2/RP1 engines.

I always liked the idea of being able to use the LAS as a pseudo third stage: that way it's exercised every flight, and you don't re-enter with the added propellant mass - or land with it on board.

I wonder if they'd fly the cargo module with the crew version. If so, adding LAS to that seems possible; we now know it has thrusters and presumably tanks. There'd be room under the fairing for larger tanks and engines. You'd need a way for DC to separate from the module during the abort.

Yes, DC has given us years of fun speculating!
Explosive bolts and separation (braking motors) on module?
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: russianhalo117 on 08/18/2019 12:58 am
Do we know how Dreamchaser is powered? Is there a fuel cell, or just batteries, or some other thing?

Batteries and solar panels.

The crew version didn't/won't have the solar panels from the cargo module, right? Does it just rely on batteries?
Fuel cells, batteries and SAP's. Depending on the iteration reviewed it has had all of the above mentioned. With crew not the primary focus there are moderate differences and different scale of airframe due to cargo being fairing internal diameter limited. Crew cannot be in a normal full fairing in present design. Could in theory design a custom fairing but that is unlikely.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Lar on 08/18/2019 03:08 am
funky mission icons in that FPIP
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Sesquipedalian on 09/24/2019 02:45 am
So there may be a situation here...

Peregrine is currently scheduled for Spring (March-June) 2021 as the FIRST flight of Vulcan.
Dream Chaser is currently scheduled for September 2021 as the SECOND flight of Vulcan.

I assume that the Dream Chaser team negotiated for it to not be on the first flight.

Based on the post here (https://forum.nasaspaceflight.com/index.php?topic=47773.msg1995512#msg1995512), Peregrine will be delayed until Fall or Winter 2021 even if the protest is resolved soon, which implies an even bigger delay if the protest is not resolved soon.  So what happens if Peregrine is delayed past the scheduled launch date for Dream Chaser?

I very much doubt that Dream Chaser would suffer a corresponding day-for-day slip with Peregrine, simply because contract requirements and ISS scheduling are strong incentives for it to launch on time.  How comfortable would the Dream Chaser team be if they had to modify their contract to be on the first flight of Vulcan?
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: TrevorMonty on 09/24/2019 04:49 pm
Atlas will be backup LV for DC. ULA will be flying both  Atlas and Vulcan while they make switch to Vulcan.

My pick is there will be few spare Atlas on hand to cover earlier failures of Vulcan.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Sesquipedalian on 09/25/2019 03:10 am
That's ... not the question I asked.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: envy887 on 09/25/2019 05:41 pm
That's ... not the question I asked.

I doubt anyone with direct knowledge to answer the question you asked is allowed to do so, so all you are likely to get is speculation.

My speculation: if Vulcan can't get a demo off before the DC flight, the DC team will take Atlas instead.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Alpha Control on 10/15/2019 10:29 pm
https://twitter.com/NASASpaceflight/status/1184150505720897537

No windows?? Why?  Why would you not have windows on a crew vehicle?
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: whitelancer64 on 10/15/2019 11:19 pm
https://twitter.com/NASASpaceflight/status/1184150505720897537

No windows?? Why?  Why would you not have windows on a crew vehicle?

Windows are heavy - 500 lbs - and the outer mold line is changed.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: MATTBLAK on 10/15/2019 11:37 pm
They could always use 4k video screens instead of windows. Cameras in the hull to relay them can be cellphone cam sized.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Alpha Control on 10/16/2019 04:19 am
They could always use 4k video screens instead of windows. Cameras in the hull to relay them can be cellphone cam sized.

But the original design for crew Dream Chaser was always windows.  Throughout all the design reviews, and the proposal to NASA for Commercial Crew.

So why change it? Yes, there is a weight factor for windows, but that was part of the design.

I can't imagine any pilot who would want to land on a runway (even in autoland) but can't see out the window.  Since at least Gemini, every crew spacecraft has had windows - including the news ones: Orion, Starliner, & Dragon 2.  Humans like windows.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: MATTBLAK on 10/16/2019 05:03 am
Yeah, all true. But if they don't want to/can't budget it - either by weight or cost - I was trying to offer a pragmatic solution. Somebody, somewhere will do something like it, sometime I'm picking.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: ShawnGSE on 10/16/2019 05:38 am
They could always use 4k video screens instead of windows. Cameras in the hull to relay them can be cellphone cam sized.

But the original design for crew Dream Chaser was always windows.  Throughout all the design reviews, and the proposal to NASA for Commercial Crew.

So why change it? Yes, there is a weight factor for windows, but that was part of the design.

I can't imagine any pilot who would want to land on a runway (even in autoland) but can't see out the window.  Since at least Gemini, every crew spacecraft has had windows - including the news ones: Orion, Starliner, & Dragon 2.  Humans like windows.

The proposal for Commercial Crew was scrapped after it was rejected.  Every version of Dream Chaser I've seen connected with CRS2 has not had windows since it's just a cargo vehicle.  Even SNC's own youtube videos show the windowless version. 
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: happyflower on 10/16/2019 09:50 am
Windows or no, its a very attractive spaceship.

I love that we will have two providers moving mass down from space after DC is operational.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Hog on 10/16/2019 02:44 pm
Windows or no, its a very attractive spaceship.

I love that we will have two providers moving mass down from space after DC is operational.
Yes, everyone forgets about the non-destructive downmass capabilities.  STS provided mucho downmass with 230,000 pound max nominal and 240,000 max off-nominal landing gross weights.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Lee Jay on 10/16/2019 03:14 pm
Steve Lindsey said something funny right after John Curry's window comment.  He said he's firmly on both sides of the window issue.

I'm with him.

Preserving aerodynamics, saving weight and making the pressure shell stronger are good reasons to get rid of the windows.  We have great synthetic vision technology now, where we can integrate visual, near-IR and thermal images into a scene you couldn't see with your eyes.  I can also see wanting to have windows if I were manually landing the craft or especially if I were using the craft for space tourism.  I can't imagine a lack of windows going down well with that group.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Rocket Science on 10/16/2019 03:27 pm
No windows? Oh great, bring back the X-38/CRV "Vomit Van" simulator...
https://pdfs.semanticscholar.org/167d/b4216eff88e30935d7295450737304c8a124.pdf
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: w9gb on 10/16/2019 09:15 pm
Sierra Nevada Corp. (SNC) has the Structural Test Article (STA), which is the Crew prototype for Dream Chaser,
and the first Cargo Dragon space frame/wings being finished by Lockheed’s Fort Worth facility.

Today, during the media news conference regarding SNC Dream Chaser, Jeff Foust of space.com asked a question to Steve Lindsey, VP of Space Exploration Systems Space Systems about the construction of a second Cargo Dragon.

Based on Mr. Lindsey’s response to the question, it sounded like the second (and third) space-frame would not be built until performance data from the CRS-2 space flight in 4Q 2021 is received by SNC.  That would mean a second Dream Chaser space-frame would not be available until 2024 ??

gb
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Coastal Ron on 10/16/2019 10:01 pm
Preserving aerodynamics, saving weight and making the pressure shell stronger are good reasons to get rid of the windows.  We have great synthetic vision technology now, where we can integrate visual, near-IR and thermal images into a scene you couldn't see with your eyes.

Not only great sensors, but great displays too. Considering that some of the landings could be at night or in inclement weather, a large display might be preferred over tiny windows anyways.

Quote
I can also see wanting to have windows if I were manually landing the craft or especially if I were using the craft for space tourism.  I can't imagine a lack of windows going down well with that group.

There is no tourist market, so this is not a consideration. And if there was, the tourists would be more concerned with their view from orbit than the short ride down to terra firma.

Can't wait to see Dream Chaser fly!
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Lars-J on 10/17/2019 12:19 am
As far as "no windows", that is SNC's line, I doubt it is NASA's line of thinking. ...unless there is a massive amount of hypocrisy at NASA regarding the need for windows. I doubt certain other contractors could get away with such a proposal.

And now I read from the update thread: "Lee Jay for NSF about Dream Chaser testing. No more free flight tests, per John Curry."

No more flight tests? Geez. Not sure any other contractor could get away with that, but the wing amazing peoples at NASA don't die off quickly, it seems. It's amazing what a winged concept lets you skip, testing-wise.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: TrevorMonty on 10/17/2019 02:20 am
Sierra Nevada Corp. (SNC) has the Structural Test Article (STA), which is the Crew prototype for Dream Chaser,
and the first Cargo Dragon space frame/wings being finished by Lockheed’s Fort Worth facility.

Today, during the media news conference regarding SNC Dream Chaser, Jeff Foust of space.com asked a question to Steve Lindsey, VP of Space Exploration Systems Space Systems about the construction of a second Cargo Dragon.

Based on Mr. Lindsey’s response to the question, it sounded like the second (and third) space-frame would not be built until performance data from the CRS-2 space flight in 4Q 2021 is received by SNC.  That would mean a second Dream Chaser space-frame would not be available until 2024 ??

gb
Having 2nd vehicle would be nice for redundancy, just encase they lose 1st one eg LV failure. Its lot of money to outlay for low risk what if, especially given ULA excellent flight record. NASA don't need it as they have Cygnus and Dragon to fall back on.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Lee Jay on 10/17/2019 01:13 pm
As far as "no windows", that is SNC's line, I doubt it is NASA's line of thinking. ...unless there is a massive amount of hypocrisy at NASA regarding the need for windows. I doubt certain other contractors could get away with such a proposal.

And now I read from the update thread: "Lee Jay for NSF about Dream Chaser testing. No more free flight tests, per John Curry."

No more flight tests? Geez. Not sure any other contractor could get away with that, but the wing amazing peoples at NASA don't die off quickly, it seems. It's amazing what a winged concept lets you skip, testing-wise.

What he said was that they got everything they needed from the first two drop tests.

My guess is, they could really use more but they can't get it - they need hypersonic and transonic data but can't get it from a drop test so there's no point in doing additional low-speed drop tests.

Enterprise flew 5 times.  Given better simulation capabilities, I think it's reasonable that these two drop tests told them what they needed to know about the low-speed regime.

There were originally plans to tow a crew-version to high altitude, drop it and ignite the hybrids to push the vehicle supersonic.  I'm guessing they eventually deemed this not worth the effort given the amount of effort it would take to do it with the cargo vehicle that doesn't have the hybrids.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Lee Jay on 10/17/2019 01:19 pm
Sierra Nevada Corp. (SNC) has the Structural Test Article (STA), which is the Crew prototype for Dream Chaser,
and the first Cargo Dragon space frame/wings being finished by Lockheed’s Fort Worth facility.

Today, during the media news conference regarding SNC Dream Chaser, Jeff Foust of space.com asked a question to Steve Lindsey, VP of Space Exploration Systems Space Systems about the construction of a second Cargo Dragon.

Based on Mr. Lindsey’s response to the question, it sounded like the second (and third) space-frame would not be built until performance data from the CRS-2 space flight in 4Q 2021 is received by SNC.  That would mean a second Dream Chaser space-frame would not be available until 2024 ??

gb
Having 2nd vehicle would be nice for redundancy, just encase they lose 1st one eg LV failure. Its lot of money to outlay for low risk what if, especially given ULA excellent flight record. NASA don't need it as they have Cygnus and Dragon to fall back on.


That's an over-simplification of the answer given, if not an outright misrepresentation.

"We're already working with Lockheed and others looking at that second structure and when we're going to start that but our intent has always been to build a second vehicle."  -- Steve Lindsey

John Curry told me he wants to start the second one right away to keep the build team together.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: PahTo on 10/17/2019 04:15 pm
I forgot to mention something that I found interesting.

Do you know why parts of the structure (especially the top and bottom) are brown/gold in color, when the thing is mostly black carbon fiber?  It's copper mesh embedded into the composite to help with lightning strike protection.

Thanks Lee Jay, but that begs the question:  what need is there for lightning protection if the vehicle is fully enclosed in a fairing on ascent; and controllers can wait a day (or more) at ISS if there are Tstorms forecast on the day of return?
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Eric Hedman on 10/17/2019 04:38 pm
I forgot to mention something that I found interesting.

Do you know why parts of the structure (especially the top and bottom) are brown/gold in color, when the thing is mostly black carbon fiber?  It's copper mesh embedded into the composite to help with lightning strike protection.

Thanks Lee Jay, but that begs the question:  what need is there for lightning protection if the vehicle is fully enclosed in a fairing on ascent; and controllers can wait a day (or more) at ISS if there are Tstorms forecast on the day of return?
It is possible for lightning strikes in clear skies:

http://www.nbcnews.com/id/43941393/ns/technology_and_science-science/t/when-lightning-strikes-out-blue-sky/#.XaiYhGZOmM8 (http://www.nbcnews.com/id/43941393/ns/technology_and_science-science/t/when-lightning-strikes-out-blue-sky/#.XaiYhGZOmM8)
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: gemmy0I on 10/17/2019 04:55 pm
Thanks Lee Jay, but that begs the question:  what need is there for lightning protection if the vehicle is fully enclosed in a fairing on ascent; and controllers can wait a day (or more) at ISS if there are Tstorms forecast on the day of return?
Given that rapid return of time-sensitive experiments is one of Dream Chaser's key selling points, I imagine they'd rather have the vehicle equipped to handle a wide range of weather so it doesn't have to delay its return at the last minute. (Granted, landing in a different location is always an option, but probably an undesirable one if there's time-sensitive cargo on board - since landing near the cargo's processing destination is key for speed.)

For the crew version this could be especially valuable. IIRC Dream Chaser has been sold as especially well-suited to e.g. medical evacuations from the ISS, due to its relatively gentle g-force environment during reentry and landing compared to conventional capsules. A medical emergency won't wait for the weather, and while the craft's ability to land at most major airport runways will certainly help improve options (most major cities have both a well-equipped hospital and an airport with a sufficiently long runway), I'm sure they'd prefer to land at the intended runway where the NASA flight surgeons can get immediate access (rather than relying on doctors who aren't trained in the subtleties of spaceflight).
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Prettz on 10/23/2019 08:08 pm
The proposal for Commercial Crew was scrapped after it was rejected.  Every version of Dream Chaser I've seen connected with CRS2 has not had windows since it's just a cargo vehicle.  Even SNC's own youtube videos show the windowless version.
If they're ruling out future windows for a crewed version, I'd say they're ruling out a future crewed version. There's no reason to send humans into space without real windows. Too bad, I was in love with the crewed DC.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: DistantTemple on 10/23/2019 08:55 pm
The proposal for Commercial Crew was scrapped after it was rejected.  Every version of Dream Chaser I've seen connected with CRS2 has not had windows since it's just a cargo vehicle.  Even SNC's own youtube videos show the windowless version.
If they're ruling out future windows for a crewed version, I'd say they're ruling out a future crewed version. There's no reason to send humans into space without real windows. Too bad, I was in love with the crewed DC.
A few months ago I read (I think on SNC's website) that future crewed versions remained an aspiration, and care was being taken not to take engineering decisions that would preclude a version of the same ship for HSF. The owners of SNC seem to hold the concept dear!
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: JEF_300 on 10/24/2019 03:37 am
There's no reason for you guys to be speculating on what they said about windows when you can just watch them say it. I've added a timestamp for your conveinence; the video should start right before they begin the window discussion.

https://www.youtube.com/watch?v=206KQCRxjGk?t=2828

To summarize:

A. Nothing has been ruled out.
B. They were definitely talking about doing the crew version without windows.
C. It was more of a side remark than an announcement.

Really, it's not even worth thinking about much at this point.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: su27k on 10/26/2019 02:49 am
I think it's worth to point out that CCT-REQ-1130, the Commercial Crew requirement document, requires the spacecraft to have windows that can be used by crew during all phases of flight.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: JAFO on 10/26/2019 06:20 am
Steve Lindsey said something funny right after John Curry's window comment.  He said he's firmly on both sides of the window issue.

I'm with him.

Preserving aerodynamics, saving weight and making the pressure shell stronger are good reasons to get rid of the windows.  We have great synthetic vision technology now, where we can integrate visual, near-IR and thermal images into a scene you couldn't see with your eyes.  I can also see wanting to have windows if I were manually landing the craft or especially if I were using the craft for space tourism.  I can't imagine a lack of windows going down well with that group.
Pilots are paid to be pessimists. I've never had an engine fail, but I practice for them. I've flown Cat IIIb approaches and trusted the aircraft, but I also kept my hands on the controls, just in case. TV screens fail, software can have a bug at the worst possible time.

I hope I'm around to see a mannned Dream Chaser (with windows) land.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: joncz on 10/26/2019 02:06 pm
I think it's worth to point out that CCT-REQ-1130, the Commercial Crew requirement document, requires the spacecraft to have windows that can be used by crew during all phases of flight.

https://www.youtube.com/watch?v=hAyJiNobfY8
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: dwheeler on 10/31/2019 11:07 pm
New ConOps video:

https://twitter.com/SierraNevCorp/status/1189977612623302657


Still showing windows in the crewed version in this video...
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Alpha Control on 11/01/2019 12:45 am
There's no reason for you guys to be speculating on what they said about windows when you can just watch them say it. I've added a timestamp for your conveinence; the video should start right before they begin the window discussion.

https://www.youtube.com/watch?v=206KQCRxjGk?t=2828

To summarize:

A. Nothing has been ruled out.
B. They were definitely talking about doing the crew version without windows.
C. It was more of a side remark than an announcement.

Really, it's not even worth thinking about much at this point.

Good point. But we're talking about it now only because it came up in this presentation. IMHO, I think windows will win out.  Why? Because it's too basic - humans like to see where they're going, and they like the certainty that what they see is true. And that's it.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: TripleSeven on 11/01/2019 01:08 am


Good point. But we're talking about it now only because it came up in this presentation. IMHO, I think windows will win out.  Why? Because it's too basic - humans like to see where they're going, and they like the certainty that what they see is true. And that's it.

because people are nuts to get on a vehicle that when push comes to shove...they or someone in the crew...cannot fly

SNC is a well run company
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Steven Pietrobon on 11/01/2019 04:53 am
Definitely has windows!
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: vt_hokie on 11/01/2019 02:27 pm
I was hesitant to comment on what may or may not someday happen with the notional crew variant, as it's really rather premature at this stage, but I would just point out that NASA's X-59 QSST demonstrator will use a 4k video display in lieu of a forward facing windshield, as the supersonic vehicle's very long boom suppression nose makes a Concorde-like retractable nose impractical.  So, it won't be unprecedented I suppose should that solution be used elsewhere.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: JAFO on 12/24/2019 12:33 am
After being eliminated from Commercial Crew in favor of Boeing, I can only imagine what they're thinking at SNC right now.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Lars-J on 12/24/2019 04:58 am
After being eliminated from Commercial Crew in favor of Boeing, I can only imagine what they're thinking at SNC right now.

Believing that SNC would run into no issues would be ... premature. But we'll see how smooth the first cargo DC test flight goes.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Rocket Science on 12/24/2019 10:13 am
Dream Chaser as all spacecraft will have teething problems. The wish is still to see her as intended as a crewed version with her adult teeth and what bite she could take from the market...
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: ncb1397 on 12/24/2019 10:22 am
After being eliminated from Commercial Crew in favor of Boeing, I can only imagine what they're thinking at SNC right now.

Believing that SNC would run into no issues would be ... premature. But we'll see how smooth the first cargo DC test flight goes.

Even if it goes perfectly, SNC would have had substantially more time from contract award to flight to build their system and fly it than either commercial crew provider. So, you wouldn't be able to determine if being "under the gun" would have had any effect on the first flight. Furthermore, the risk of the suborbital trajectory is what ended this flight's docking with the ISS and that was driven by being crewed which won't be a factor for dream chaser. They can spend multiple orbits getting the spacecraft up and running properly. As such, if the roles were reversed and starliner was the cargo vehicle and dream chaser was the crew provider, some design decisions based on that fact could have made a material difference to the outcome of both first flights.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: TrevorMonty on 12/24/2019 05:06 pm
It maybe possible for cargo version to support crew missions. I was thinking crew boarding DC while docked at ISS, do some freeflier experiments then return to ISS. In worst case scenerio DC could return crew to earth.

Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Steven Pietrobon on 12/24/2019 10:36 pm
Furthermore, the risk of the suborbital trajectory is what ended this flight's docking with the ISS and that was driven by being crewed which won't be a factor for dream chaser.

The suborbital trajectory had nothing to do with the 25% loss of propellant. The ACS system was out of whack by 11 hours and was rapidly using up propellant. Luckily, the main thrusters did not fire at the correct time (T+31 minutes) since the spacecraft was pointing in the wrong direction (90 degrees to the flight path). The spacecraft was then manoeuvred to the correct orientation and at T+34.5 minutes, the main thrusters were fired to put the spacecraft into a stable orbit. Had Atlas V put Starliner in a stable orbit, the same problem would have occurred.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Lee Jay on 12/24/2019 10:43 pm
It maybe possible for cargo version to support crew missions. I was thinking crew boarding DC while docked at ISS, do some freeflier experiments then return to ISS. In worst case scenerio DC could return crew to earth.



Without windows and without ECLSS for crew?  I don't think so.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Lee Jay on 12/24/2019 10:48 pm
After being eliminated from Commercial Crew in favor of Boeing, I can only imagine what they're thinking at SNC right now.

Believing that SNC would run into no issues would be ... premature. But we'll see how smooth the first cargo DC test flight goes.

Even if it goes perfectly, SNC would have had substantially more time from contract award to flight to build their system and fly it than either commercial crew provider.

How do you figure that?  They were awarded the contract in January of 2016 and plan to fly in 2021 - about 5-6 years.  Commercial crew was awarded September of 2014 meaning they're already over 5 years in and haven't flown yet.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: ncb1397 on 12/24/2019 10:56 pm
After being eliminated from Commercial Crew in favor of Boeing, I can only imagine what they're thinking at SNC right now.

Believing that SNC would run into no issues would be ... premature. But we'll see how smooth the first cargo DC test flight goes.

Even if it goes perfectly, SNC would have had substantially more time from contract award to flight to build their system and fly it than either commercial crew provider.

How do you figure that?  They were awarded the contract in January of 2016 and plan to fly in 2021 - about 5-6 years.  Commercial crew was awarded September of 2014 meaning they're already over 5 years in and haven't flown yet.

First Dreamchaser flight is NET September 2021 which is about 1.75 years out (and could be delayed). Both of the commercial crew providers have flown once. SNC got a contract about 1.25 years after commecial crew awards.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Lee Jay on 12/24/2019 11:41 pm
After being eliminated from Commercial Crew in favor of Boeing, I can only imagine what they're thinking at SNC right now.

Believing that SNC would run into no issues would be ... premature. But we'll see how smooth the first cargo DC test flight goes.

Even if it goes perfectly, SNC would have had substantially more time from contract award to flight to build their system and fly it than either commercial crew provider.

How do you figure that?  They were awarded the contract in January of 2016 and plan to fly in 2021 - about 5-6 years.  Commercial crew was awarded September of 2014 meaning they're already over 5 years in and haven't flown yet.

First Dreamchaser flight is NET September 2021 which is about 1.75 years out (and could be delayed). Both of the commercial crew providers have flown once. SNC got a contract about 1.25 years after commecial crew awards.

So that would put DC at 5.75 years and we're already at 5.25 years for CCtCap, and they have only flown test flights, not operational flights.  So, it's going to end up being about the same not "substantially more time from contract award to flight".
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: yg1968 on 12/25/2019 01:06 am
It maybe possible for cargo version to support crew missions. I was thinking crew boarding DC while docked at ISS, do some freeflier experiments then return to ISS. In worst case scenerio DC could return crew to earth.



Without windows and without ECLSS for crew?  I don't think so.

I think that SNC mentioned thay an upgraded version of DC could be used as an emergency crew return vehicle (CRV). But I am not sure that there is a need for that.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: JEF_300 on 12/25/2019 02:17 am
It maybe possible for cargo version to support crew missions. I was thinking crew boarding DC while docked at ISS, do some freeflier experiments then return to ISS. In worst case scenerio DC could return crew to earth.



Without windows and without ECLSS for crew?  I don't think so.

At one of the press conferences SNC said that cargo Dreamchaser has life support good enough to support the crew, in an emergency.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Lee Jay on 12/25/2019 02:35 am
It maybe possible for cargo version to support crew missions. I was thinking crew boarding DC while docked at ISS, do some freeflier experiments then return to ISS. In worst case scenerio DC could return crew to earth.



Without windows and without ECLSS for crew?  I don't think so.

At one of the press conferences SNC said that cargo Dreamchaser has life support good enough to support the crew, in an emergency.

I was at that press conference, but only remember it being for something like an emergency return, which takes something like an hour.  Not for testing in a station flyaround or something.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: JAFO on 12/25/2019 07:19 pm
After being eliminated from Commercial Crew in favor of Boeing, I can only imagine what they're thinking at SNC right now.

Believing that SNC would run into no issues would be ... premature. But we'll see how smooth the first cargo DC test flight goes.

Even if it goes perfectly, SNC would have had substantially more time from contract award to flight to build their system and fly it than either commercial crew provider.

How do you figure that?  They were awarded the contract in January of 2016 and plan to fly in 2021 - about 5-6 years.  Commercial crew was awarded September of 2014 meaning they're already over 5 years in and haven't flown yet.

First Dreamchaser flight is NET September 2021 which is about 1.75 years out (and could be delayed). Both of the commercial crew providers have flown once. SNC got a contract about 1.25 years after commecial crew awards.


1.25 years of self-funding Dream Chaser while Boeing and SpaceX (especially Boeing) has been sucking off the government money teat and asking for more and more cash for their programs. They also had to modify the design for cargo, and to fit inside a fairing.


Imagine how much further Dream Chaser would have been if they had been fully funded and selected during the commercial crew award. No bucks, no......
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Jirka Dlouhy on 12/25/2019 09:39 pm

Believing that SNC would run into no issues would be ... premature. But we'll see how smooth the first cargo DC test flight goes.

Even if it goes perfectly, SNC would have had substantially more time from contract award to flight to build their system and fly it than either commercial crew provider.

How do you figure that?  They were awarded the contract in January of 2016 and plan to fly in 2021 - about 5-6 years.  Commercial crew was awarded September of 2014 meaning they're already over 5 years in and haven't flown yet.

First Dreamchaser flight is NET September 2021 which is about 1.75 years out (and could be delayed). Both of the commercial crew providers have flown once. SNC got a contract about 1.25 years after commecial crew awards.


1.25 years of self-funding Dream Chaser while Boeing and SpaceX (especially Boeing) has been sucking off the government money teat and asking for more and more cash for their programs. They also had to modify the design for cargo, and to fit inside a fairing.


Imagine how much further Dream Chaser would have been if they had been fully funded and selected during the commercial crew award. No bucks, no......

I see behind LMA.

Edit/Lar: Fix quotes.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: TrevorMonty on 12/26/2019 02:15 am
It maybe possible for cargo version to support crew missions. I was thinking crew boarding DC while docked at ISS, do some freeflier experiments then return to ISS. In worst case scenerio DC could return crew to earth.



Without windows and without ECLSS for crew?  I don't think so.

At one of the press conferences SNC said that cargo Dreamchaser has life support good enough to support the crew, in an emergency.

I was at that press conference, but only remember it being for something like an emergency return, which takes something like an hour.  Not for testing in a station flyaround or something.
I'd expect SNC to have crew rated ECLSS that could be added. Would've been part of their commercial crew development. Windows are optional but nice to have, even if it is a couple small side windows. NB ISS doesn't have windows in most of its modules.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Lars-J on 12/26/2019 07:13 pm
...
I see behind LMA.
Fix your quotes! It's not difficult to look at your post after posting to see if it looks right...

Anyway, people who believe the "Crew DC would have been smooth sailing" do not recall history well, or they have a blackout period around the Commercial Crew down-select period.

Crew DC was facing two significant issues:
1. Launch abort system - They had significant problem with their hybrid propulsion system around that time, and were apparently (according to sources on this forum) about to scrap theirs and start over with new abort engines technology. (I believe this uncertainly was NASA's biggest concern that prevented their selection)
2. Aerodynamic loads during ascent (or more accurately side-loads from wings)

Conveniently, these two issues were side stepped by Cargo DC, since these two issues went away:  A) no LAS! and B) lets put it in a payload fairing

Crew DC would have had to deal with these issues (and others) from the start... Issues that SNC had not solved yet. Were they solvable? Of course, but with extra time and/or funding.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: TrevorMonty on 12/26/2019 07:46 pm
SNC could work towards crew vehicle incrementally.

SNC should be able to use their test vehicle for doing a LAS test from pad. An in flight test would be very expensive, can't see them doing this if they can avoid it.

ECLSS can be tested on orbit with crew from ISS using cargo version.

Unmanned crew vehicle launch test could be paid for by flying experiments. My guess for LV is Vulcan or NG. 
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Rocket Science on 12/26/2019 11:00 pm
...
I see behind LMA.
Fix your quotes! It's not difficult to look at your post after posting to see if it looks right...

Anyway, people who believe the "Crew DC would have been smooth sailing" do not recall history well, or they have a blackout period around the Commercial Crew down-select period.

Crew DC was facing two significant issues:
1. Launch abort system - They had significant problem with their hybrid propulsion system around that time, and were apparently (according to sources on this forum) about to scrap theirs and start over with new abort engines technology. (I believe this uncertainly was NASA's biggest concern that prevented their selection)
2. Aerodynamic loads during ascent (or more accurately side-loads from wings)

Conveniently, these two issues were side stepped by Cargo DC, since these two issues went away:  A) no LAS! and B) lets put it in a payload fairing

Crew DC would have had to deal with these issues (and others) from the start... Issues that SNC had not solved yet. Were they solvable? Of course, but with extra time and/or funding.
Lars, I don't see anyone saying a crewed version would be smooth sailing (unless I missed it). Mark Sirangelo stated on the record that to zero blackout zones FWIW. Then they acquired ORBITEC and their new Vortex engines. This is a legacy NASA HL-20 program with an extensive database that was drawn upon and updated with refined wind tunnel testing. Finally they used the time to develop a new more capable cargo delivery and disposal system with the addition of the module. In life "everything" is just a matter of time and money... At least that has been my experience...
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: edzieba on 12/30/2019 09:38 am
After being eliminated from Commercial Crew in favor of Boeing, I can only imagine what they're thinking at SNC right now.
Given the wide variety of issues (both technical and bureaucratic) both CC contractors have encountered, likely something along the lines of "There but for the grace of God go I".
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: JAFO on 12/30/2019 07:00 pm
After being eliminated from Commercial Crew in favor of Boeing, I can only imagine what they're thinking at SNC right now.
Given the wide variety of issues (both technical and bureaucratic) both CC contractors have encountered, likely something along the lines of "There but for the grace of God go I".


That’s like saying “I’m glad I didn’t get that promotion because look at how hard it’s been for the guy that got it.”


Good people seek out and overcome challenges. Great people make history by overcoming them.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: JEF_300 on 12/31/2019 05:23 am
After being eliminated from Commercial Crew in favor of Boeing, I can only imagine what they're thinking at SNC right now.
Given the wide variety of issues (both technical and bureaucratic) both CC contractors have encountered, likely something along the lines of "There but for the grace of God go I".


That’s like saying “I’m glad I didn’t get that promotion because look at how hard it’s been for the guy that got it.”


Good people seek out and overcome challenges. Great people make history by overcoming them.

I think we may have unitentionally stubled across an interesting idea here.

Because they can learn from the CC contractors, and because they're making a cargo version of the vehicle first, the crew Dreamchaser development will likely go much sooner if/when it happens.

Whereas if they had gone straight into full on development of the crewed vehicle, like Boeing and SpaceX did, they'd probably be having a lot of the same problems right now.

Maybe SNC should be glad they lost the CC contract?

Edit: On the otherhand, maybe they'll have all the same problems anyway. I guess only time wil tell.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Rocket Science on 12/31/2019 04:15 pm
After being eliminated from Commercial Crew in favor of Boeing, I can only imagine what they're thinking at SNC right now.
Given the wide variety of issues (both technical and bureaucratic) both CC contractors have encountered, likely something along the lines of "There but for the grace of God go I".


That’s like saying “I’m glad I didn’t get that promotion because look at how hard it’s been for the guy that got it.”


Good people seek out and overcome challenges. Great people make history by overcoming them.

I think we may have unitentionally stubled across an interesting idea here.

Because they can learn from the CC contractors, and because they're making a cargo version of the vehicle first, the crew Starliner development will likely go much sooner if/when it happens.

Whereas if they had gone straight into full on development of the crewed vehicle, like Boeing and SpaceX did, they'd probably be having a lot of the same problems right now.

Maybe SNC should be glad they lost the CC contract?

Edit: On the otherhand, maybe they'll have all the same problems anyway. I guess only time wil tell.
"We learn by doing"... :)
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: JAFO on 12/31/2019 06:52 pm
"Sure am glad the Soviets sent Gagarin into orbit first."

 said no one at NASA in 1961......





(Apologies, Mods, I'll let it go now. Thread being trimmed in 3... 2... 1...)




Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: edzieba on 12/31/2019 07:22 pm
After being eliminated from Commercial Crew in favor of Boeing, I can only imagine what they're thinking at SNC right now.
Given the wide variety of issues (both technical and bureaucratic) both CC contractors have encountered, likely something along the lines of "There but for the grace of God go I".


That’s like saying “I’m glad I didn’t get that promotion because look at how hard it’s been for the guy that got it.”


Good people seek out and overcome challenges. Great people make history by overcoming them.

I think we may have unitentionally stubled across an interesting idea here.

Because they can learn from the CC contractors, and because they're making a cargo version of the vehicle first, the crew Starliner development will likely go much sooner if/when it happens.

Whereas if they had gone straight into full on development of the crewed vehicle, like Boeing and SpaceX did, they'd probably be having a lot of the same problems right now.

Maybe SNC should be glad they lost the CC contract?

Edit: On the otherhand, maybe they'll have all the same problems anyway. I guess only time wil tell.
"We learn by doing"... :)
It is, however, much cheaper to learn by someone else doing.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Alpha Control on 01/01/2020 04:59 pm
After being eliminated from Commercial Crew in favor of Boeing, I can only imagine what they're thinking at SNC right now.
Given the wide variety of issues (both technical and bureaucratic) both CC contractors have encountered, likely something along the lines of "There but for the grace of God go I".


That’s like saying “I’m glad I didn’t get that promotion because look at how hard it’s been for the guy that got it.”


Good people seek out and overcome challenges. Great people make history by overcoming them.

I think we may have unitentionally stubled across an interesting idea here.

Because they can learn from the CC contractors, and because they're making a cargo version of the vehicle first, the crew Starliner development will likely go much sooner if/when it happens.

Whereas if they had gone straight into full on development of the crewed vehicle, like Boeing and SpaceX did, they'd probably be having a lot of the same problems right now.

Maybe SNC should be glad they lost the CC contract?

Edit: On the otherhand, maybe they'll have all the same problems anyway. I guess only time wil tell.

Interesting thought.  And you mean crew Dream Chaser, right, not Starliner?
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: JEF_300 on 01/01/2020 09:19 pm
Because they can learn from the CC contractors, and because they're making a cargo version of the vehicle first, the crew Starliner development will likely go much sooner if/when it happens.

Interesting thought.  And you mean crew Dream Chaser, right, not Starliner?

Whoops. Yes, good catch.

Starliner Dreamchaser Dreamliner Starchaser... aerospace companies are gonna have to start coming up with more original names sooner or later.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Rocket Science on 01/01/2020 11:48 pm
After being eliminated from Commercial Crew in favor of Boeing, I can only imagine what they're thinking at SNC right now.
Given the wide variety of issues (both technical and bureaucratic) both CC contractors have encountered, likely something along the lines of "There but for the grace of God go I".


That’s like saying “I’m glad I didn’t get that promotion because look at how hard it’s been for the guy that got it.”


Good people seek out and overcome challenges. Great people make history by overcoming them.

I think we may have unitentionally stubled across an interesting idea here.

Because they can learn from the CC contractors, and because they're making a cargo version of the vehicle first, the crew Starliner development will likely go much sooner if/when it happens.

Whereas if they had gone straight into full on development of the crewed vehicle, like Boeing and SpaceX did, they'd probably be having a lot of the same problems right now.

Maybe SNC should be glad they lost the CC contract?

Edit: On the otherhand, maybe they'll have all the same problems anyway. I guess only time wil tell.
"We learn by doing"... :)
It is, however, much cheaper to learn by someone else doing.
Yes, I said that years ago when SpaceX proposed landing and re-using the first stage while other LV providers sat back and watched the experiment. We now know it's possible but still not the economics of it.
In a competitive market you can only "afford" to watch for so long. Sometime you have to "pay to play" to get in the game, that's what they call investment...
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Glorky FCY on 01/31/2020 07:49 pm
If a Dream Chaser were to fly astronauts, how would it do an IFA?
Would it just separate from its rocket and fire its vortex thrusters?
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: wings_no_capsules on 02/10/2020 05:20 pm
adapt the SLS adapter ring to take DC......

Dream chaser to MARS!
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Ike17055 on 02/12/2020 08:58 pm
"Sure am glad the Soviets sent Gagarin into orbit first."

 said no one at NASA in 1961......



well, maybe. but in "from the earth to the moon," James Webb was quoting (in 1961) as saying that if we had beaten Gagarin to orbit, "that would be it; it would be over.  no one would be talking about going to the moon for another 20 years."  so if they hadn't said it, maybe they should have...
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: joek on 02/12/2020 09:50 pm
...
Whereas if they had gone straight into full on development of the crewed vehicle, like Boeing and SpaceX did, they'd probably be having a lot of the same problems right now.
...

SpaceX started with, and had extensive experience with, Cargo Dragon before Dragon Crew.  Although Dragon Cargo and Crew are significantly different, would not assume one is much like the other.  Not to mention that Dream Chaser's first attempt was for a crewed vehicle (which was not selected or awarded a contract (https://www.nasa.gov/sites/default/files/files/CCtCap-Source-Selection-Statement-508(3).pdf); note specifically MPS weakness).

Certainly if SNC had been selected they would be facing similar or worse (likely worse).  Have or will they address those issues?  Maybe.  So yes, maybe wise of them to learn from other's experiences--although I expect they would have preferred the contract and learned themselves.

In short, experience with cargo should not be taken as a precedent when it comes to crew--very different animals (at least in NASA's eyes).  When SNC can successfully deliver cargo, they might be ready for the next step to crew, but I expect that will be a long and complex step, their success with cargo notwithstanding.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: joek on 02/12/2020 09:52 pm
If a Dream Chaser were to fly astronauts, how would it do an IFA?
Would it just separate from its rocket and fire its vortex thrusters?
More or less, at least theoretically (per SNC's original proposal for crew flights).  Devil is in the details.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: adrianwyard on 02/12/2020 11:59 pm
Just to remind us of the obvious: any escape capability on a crewed Dream Chaser would require the addition of powerful motors that are not present on the cargo version.

We've no idea what form they'd take; perhaps SRBs on the cargo module, perhaps larger tanks/engines on the Dream Chaser itself (requiring an internal redesign). No option I can think of will be quick or easy to develop and test.

OTOH it would be a comparatively trivial matter to convert a (Cargo) Dream Chaser for crew return once it has a good safety record.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: vt_hokie on 02/13/2020 07:08 pm
Just to remind us of the obvious: any escape capability on a crewed Dream Chaser would require the addition of powerful motors that are not present on the cargo version.

We've no idea what form they'd take; perhaps SRBs on the cargo module, perhaps larger tanks/engines on the Dream Chaser itself (requiring an internal redesign). No option I can think of will be quick or easy to develop and test.


Presumably this was already worked out with the commercial crew proposal, which was submitted after SNC had already ditched the hybrids in favor of liquid fueled engines. 
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: adrianwyard on 02/13/2020 07:28 pm
Given that SNC didn't acquire Orbitech until June 2014 (and their losing out to Boeing and SpaceX was announced in September) I wonder how far along their liquid plans could have been...

I remember the Dream Chaser abort system was criticized by NASA reviewers, presumably that was the hybrids.

It occurs to me that any escape system will need hefty pitch control to keep it from flipping when in windy/thicker air. Fixed solids on the cargo module/stage adapter would not provide that - something will need to gimbal or differentially thrust far off axis.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: FutureSpaceTourist on 02/27/2020 07:16 pm
https://twitter.com/sierranevcorp/status/1233119738492063746

Quote
Lauren here w/the solar array hinges for the Dream Chaser® spaceplane. The solar arrays go from a compacted, stacked configuration, to a fully deployed wing. To get to that state, they need these hinges!
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: JAFO on 02/29/2020 10:12 pm
After being eliminated from Commercial Crew in favor of Boeing, I can only imagine what they're thinking at SNC right now.
Given the wide variety of issues (both technical and bureaucratic) both CC contractors have encountered, likely something along the lines of "There but for the grace of God go I".


That’s like saying “I’m glad I didn’t get that promotion because look at how hard it’s been for the guy that got it.”


Good people seek out and overcome challenges. Great people make history by overcoming them.

I think we may have unitentionally stubled across an interesting idea here.

Because they can learn from the CC contractors, and because they're making a cargo version of the vehicle first, the crew Starliner development will likely go much sooner if/when it happens.

Whereas if they had gone straight into full on development of the crewed vehicle, like Boeing and SpaceX did, they'd probably be having a lot of the same problems right now.

Maybe SNC should be glad they lost the CC contract?

Edit: On the otherhand, maybe they'll have all the same problems anyway. I guess only time wil tell.
"We learn by doing"... :)
It is, however, much cheaper to learn by someone else doing.
Except that no one else is doing what SNC is doing.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Comga on 03/01/2020 01:41 am
Starliner Dreamchaser Dreamliner Starchaser... aerospace companies are gonna have to start coming up with more original names sooner or later.
Like Magic Dragon?  ;D
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: JEF_300 on 03/01/2020 07:09 am
...
Whereas if they had gone straight into full on development of the crewed vehicle, like Boeing and SpaceX did, they'd probably be having a lot of the same problems right now.
...
In short, experience with cargo should not be taken as a precedent when it comes to crew--very different animals (at least in NASA's eyes).  When SNC can successfully deliver cargo, they might be ready for the next step to crew, but I expect that will be a long and complex step, their success with cargo notwithstanding.

My point was less that SNC will gain experience from cargo Dreamchaser, and moreso that SNC will learn from SpaceX and Boeing's experience with crewed spacecraft.

I think all of us could probably putt together a pretty solid 'do' and 'do-not' list based on the commercial crew tests so far. Sometimes it feels like they're trying to make it easy.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: joek on 03/01/2020 07:21 am
My point was less that SNC will gain experience from cargo Dreamchaser, and moreso that SNC will learn from SpaceX and Boeing's experience with crewed spacecraft.
...

Agree, but also expect that a significant portion of the lessons-learned are on the NASA side, which I hope and expect will make it easier for new entrants.  (Not necessarily easier from a requirements perspective, but a better definition of NASA's role and the line between insight-oversight.)
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: adrianwyard on 03/09/2020 04:12 pm
I'm not quite up to the challenge but it would be possible to determine if there's sufficient available volume in Dream Chaser to house tanks large enough for abort - given its mass, the energy density and likely ISP of H2O2/RP1 engines.

I always liked the idea of being able to use the LAS as a pseudo third stage: that way it's exercised every flight, and you don't re-enter with the added propellant mass - or land with it on board.

I wonder if they'd fly the cargo module with the crew version. If so, adding LAS to that seems possible; we now know it has thrusters and presumably tanks. There'd be room under the fairing for larger tanks and engines. You'd need a way for DC to separate from the module during the abort.

Yes, DC has given us years of fun speculating!

Scott Manley just answered part of my question in his recent video about Black Arrow (which also used Peroxide and RP1):

https://youtu.be/FKRkFwc9234

In short, that propellant combination seems a plausible choice for abort in terms of density and ISP.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Rondaz on 03/20/2020 12:50 pm
Sounds like Vulcan has an additional Dream Chaser flight on its manifest beyond the six which were announced last year.

https://twitter.com/nextspaceflight/status/1240844789957840897
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: baldusi on 04/02/2020 08:25 am
[...]
In short, that propellant combination seems a plausible choice for abort in terms of density and ISP.

HTP+RP-1 is not hypergolic. BUT, if you pass your HTP through a catalytic bead first, the HTP get transformed into a very hot and oxygen-rich gas that will ignite with RP-1 if mixed correctly. So, both answers are correct: liquid-liquid HTP/RP-1 is NOT hypdergolic, and a HTP/RP-1 rocket CAN be done hypergolic.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Robotbeat on 04/02/2020 02:09 pm
[...]
In short, that propellant combination seems a plausible choice for abort in terms of density and ISP.

HTP+RP-1 is not hypergolic. BUT, if you pass your HTP through a catalytic bead first, the HTP get transformed into a very hot and oxygen-rich gas that will ignite with RP-1 if mixed correctly. So, both answers are correct: liquid-liquid HTP/RP-1 is NOT hypdergolic, and a HTP/RP-1 rocket CAN be done hypergolic.
Also, I think you can add a liquid catalyst to the kerosene that might make it hypergolic on contact with HTP.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: adrianwyard on 04/02/2020 04:22 pm
I wonder if the RCS thrusters will use that ignition technique.

We're close to knowing enough parameters to ballpark the size and weight of tanks needed to power a launch abort capability - but I suspect it would be significant. Good thing Atlas/Vulcan has space for a few more solid boosters... If (big if) it were developed it would give Dream Chaser substantial maneuvering options once in orbit.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: adrianwyard on 04/03/2020 06:08 am
Apparently SNC's Hybrid motors are still under active development, so would be a candidate for any Crewed Dream Chaser abort capability:

https://forum.nasaspaceflight.com/index.php?topic=29416.msg2064857#msg2064857
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Rocket Science on 04/22/2020 09:31 pm
Great article Lee, thank you! :) I'll take any good news I can during these times...
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: JAFO on 05/01/2020 09:52 pm
I was hoping for Constitution, or SNC Dale Reed.

(https://pbs.twimg.com/profile_images/730158317767524352/dj3ZnanN_bigger.jpg)Sierra Nevada Corporation@SierraNevCorpBig News! SNC is naming its first orbital vehicle set to launch with NASA: Dream Chaser Tenacity! Without SNC's tenacity, our Dream Chaser® spaceplane wouldn't be what it is today.  This name honors the grit, perseverance & hard work of the team. #NationalSpaceDay (https://twitter.com/hashtag/NationalSpaceDay?src=hashtag_click)
https://twitter.com/sierranevcorp?lang=en



Still a amazing people.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: tyrred on 05/02/2020 08:02 am
https://twitter.com/SierraNevCorp/status/1256284288196075522

I see what they did there.  Clever.  I like that Dream Chaser is still alive and kicking. Maybe the new name will grow on me.

The music is just a bit... off.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: JEF_300 on 05/07/2020 02:47 am
Historically, the idea of a manned spaceplane of the general size and shape of Dreamchaser has been under serious consideration, with money and engineering brainpower assigned to it, essentially non-stop for the past 65+ years, across several nations, often by multiple agencies simultaneously.

Dreamchaser is the culmination of a Tenacious idea. I think Tenacity a great name.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Lars-J on 05/14/2020 11:32 pm
https://twitter.com/sierranevcorp/status/1257746998767300608

Quote
Carson again! As a human systems engineer, I work to keep the crew safe & working productively as they perform tasks inside the Dream Chaser® spaceplane like opening hatches & stowing cargo. Here @NASA_Astronauts @Astro_Kimbrough & Frank Rubio open a panel to stow cargo.

Wow, that cabin is far more cramped/thinner than I anticipated. Would be tricky to fit suited up astronauts in there for a crew version.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: MoaMem on 05/15/2020 02:01 am
Wow, that cabin is far more cramped/thinner than I anticipated. Would be tricky to fit suited up astronauts in there for a crew version.
If memory serves, DC size was significantly reduced for CRS-2 to be able to fit inside a fairing.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Lars-J on 05/15/2020 03:26 am
Wow, that cabin is far more cramped/thinner than I anticipated. Would be tricky to fit suited up astronauts in there for a crew version.
If memory serves, DC size was significantly reduced for CRS-2 to be able to fit inside a fairing.
Maybe - but as far as I recall the only concession for fairing size was the folding wings. But otherwise it should be the same size as the crew version. (But I could be wrong)

The size of that central tube looks close enough to the crew dragon flight landing test vehicle:
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: JEF_300 on 05/16/2020 10:57 pm
I think that image was just of the tunnel in the back. The 'cockpit' area upfront should be bigger, or at least tall enough that you wouldn't have to crawl.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Prettz on 05/17/2020 02:00 pm
Wow, that cabin is far more cramped/thinner than I anticipated. Would be tricky to fit suited up astronauts in there for a crew version.
If memory serves, DC size was significantly reduced for CRS-2 to be able to fit inside a fairing.
It's the same size. The wings fold to let it fit in a fairing.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: JazzFan on 05/17/2020 02:17 pm
The crew version at least was envisioned to be "bigger on the inside."

(https://forum.nasaspaceflight.com/index.php?action=dlattach;topic=31887.0;attach=526534;sess=16664)

Uploaded by Rocket Science

https://forum.nasaspaceflight.com/index.php?topic=31887.40
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: TrevorMonty on 05/17/2020 04:32 pm
I think crew version had hatch above cockpit for crew to board on launch pad.  Tunnel was for use in space only.

Cargo module will have late load hatch, no access to inside of Dreamchaser once on LV and vertical.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: ncb1397 on 05/17/2020 04:58 pm
Top image is the "cockpit" area. Bottom image shows the 3 areas - shooting star cargo section, tunnel and "cockpit" area in receding order.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: brickmack on 05/18/2020 05:52 pm
I think crew version had hatch above cockpit for crew to board on launch pad.  Tunnel was for use in space only.

Cargo module will have late load hatch, no access to inside of Dreamchaser once on LV and vertical.

No, theres a late-hoad hatch on the dorsal side of the spaceplane itself. Yes, it is accessible while stacked on the LV vertically.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Rocket Science on 06/06/2020 04:43 pm
The crew version at least was envisioned to be "bigger on the inside."

(https://forum.nasaspaceflight.com/index.php?action=dlattach;topic=31887.0;attach=526534;sess=16664)

Uploaded by Rocket Science

https://forum.nasaspaceflight.com/index.php?topic=31887.40
It's bigger on the inside"... Shades of Dr. Who and the Tardis! ;D
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: JAFO on 06/07/2020 04:58 am
I'm not on Twitter, someone needs to invite Kyle to the forum. I hope the team knows how many of us homebuilders are jealous of what they're doing.

His posts made me order a t-shirt and sticker for my tool box. (You know you're a space geek when....)



https://twitter.com/SierraNevCorp/status/1268271287882911744 (https://twitter.com/SierraNevCorp/status/1268271287882911744)
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Rocket Science on 06/14/2020 04:27 pm
Interesting how the Cargo DC in the update thread without the TPS retains the same mold-line as the Crew Dream Chaser windscreen...
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Welsh Dragon on 06/14/2020 05:03 pm
Interesting how the Cargo DC in the update thread without the TPS retains the same mold-line as the Crew Dream Chaser windscreen...
Why change it and have to do all your CFD again?
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Rocket Science on 06/14/2020 08:54 pm
Interesting how the Cargo DC in the update thread without the TPS retains the same mold-line as the Crew Dream Chaser windscreen...
Why change it and have to do all your CFD again?
You're missing the point and they already had to redo the CFD for the new Cargo Dream Chaser outer mold-line with TPS...
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: GWH on 06/15/2020 03:25 pm
With SNC providing a lot of the crew module technology for Dynetics HLS lander, I am thinking it should give them a good leg up in building the crew version of dream chaser. Hopefully there is a lot of overlap in the systems they develop.

Quote
SNC is responsible for the systems integration, human rating and safety and mission assurance of the crew module, leveraging expertise developed through its NASA Commercial Resupply Services 2 (CRS-2) and NextSTEP-2/Gateway programs. At its production facilities in Louisville, Colorado, and as it did for its successful LIFE™ Gateway (Large Inflatable Fabric Environment) ground prototype, SNC will develop a ground HLS test article for crew evaluation and testing. SNC’s world-class mission control center in Louisville enable the company to provide on-orbit operations for the module, as it will for its Dream Chaser® spaceplane when it launches under NASA’s Commercial Resupply Services 2 (CRS-2) contract.

https://www.sncorp.com/press-releases/snc-nasa-artemis-hls/
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: JEF_300 on 06/15/2020 07:23 pm
Also, based on the pictures we've seen of Dreamchaser's interior, that cockpit bulge seems to have a significant portion of the total interior volume within it, so removing it would probably significantly decrease overall capability.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Lars-J on 06/15/2020 08:59 pm
With SNC providing a lot of the crew module technology for Dynetics HLS lander, I am thinking it should give them a good leg up in building the crew version of dream chaser. Hopefully there is a lot of overlap in the systems they develop.

Quote
SNC is responsible for the systems integration, human rating and safety and mission assurance of the crew module, leveraging expertise developed through its NASA Commercial Resupply Services 2 (CRS-2) and NextSTEP-2/Gateway programs. At its production facilities in Louisville, Colorado, and as it did for its successful LIFE™ Gateway (Large Inflatable Fabric Environment) ground prototype, SNC will develop a ground HLS test article for crew evaluation and testing. SNC’s world-class mission control center in Louisville enable the company to provide on-orbit operations for the module, as it will for its Dream Chaser® spaceplane when it launches under NASA’s Commercial Resupply Services 2 (CRS-2) contract.

https://www.sncorp.com/press-releases/snc-nasa-artemis-hls/

A leg up, for sure, but given the time between Cargo Dragon and Crew Dragon, it is still a significant step.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: GWH on 06/25/2020 07:19 pm
https://twitter.com/SierraNevCorp/status/1276226563244204035

Quote
In order to keep the tiles on Dream Chaser, our engineers are using room temperature vulcanizing (RTV) silicone. RTV silicone is able to withstand high temperatures, making it perfect for bonding the tiles. Each tile is tested by using a mechanism that pulls on them, which ensures the bond is sufficient.

Awesome I've got a tube of that stuff in my shop cabinet  8)

They don't say much about the tile material, does anyone know if the wikipedia entry on Dreamchaser TPS is still accurate?

Quote from: wikipedia
Its thermal protection system (TPS) was made up of silica-based tiles and a new composite material called Toughened Unipiece Fibrous Reusable Oxidation Resistant Ceramic (TUFROC)
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: adrianwyard on 06/25/2020 08:27 pm
I see they are placing temporary spacers between the tiles during application. I wonder if the gaps will be left open.

As it's launched inside a fairing they won't have to worry about rainwater getting in there and/or freezing.

Anyone know if the carbon fiber structure of Dream Chaser should experience more or less thermal expansion than the Shuttle's Aluminum body?
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Steven Pietrobon on 06/26/2020 08:09 am
They are using 2000 tiles which are stronger and lighter than that used on the Space Shuttle.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: zt on 06/26/2020 10:53 pm
How does the heat tile material / system compare with SpaceX Crew Dragon PICA-X?
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Steven Pietrobon on 06/27/2020 06:36 am
How does the heat tile material / system compare with SpaceX Crew Dragon PICA-X?

PICA-X ablates and needs to be replaced after one or more uses. The tiles are completely reusable and only need to be replaced if they become damaged.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Heinrich on 06/27/2020 11:35 am
Quote
The tiles on Dream Chaser are approximately 10 by 10 inches, while the tiles used on the Shuttle were about six by six inches. This allows fewer overall tiles to be used and helps meet all of the Micro-Meteoroid Orbital Debris requirements to ensure a the TPS is intact for a safe entry, descent, and runway landing of cargo and possible crew missions.
NSF article.


The article says that because they use larger tiles it is safer for MMOD strikes. But if an MMOD strike takes out 1 tile, a larger tile will expose a larger part of the hull. which would mean that smaller tiles are safer. Same if one falls off. What am I missing?
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: TrevorMonty on 06/27/2020 06:19 pm


I see they are placing temporary spacers between the tiles during application. I wonder if the gaps will be left open.

As it's launched inside a fairing they won't have to worry about rainwater getting in there and/or freezing.



Or chunks of foam insulation from booster tank damaging them.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Rocket Science on 06/27/2020 11:09 pm
Quote
The tiles on Dream Chaser are approximately 10 by 10 inches, while the tiles used on the Shuttle were about six by six inches. This allows fewer overall tiles to be used and helps meet all of the Micro-Meteoroid Orbital Debris requirements to ensure a the TPS is intact for a safe entry, descent, and runway landing of cargo and possible crew missions.
NSF article.


The article says that because they use larger tiles it is safer for MMOD strikes. But if an MMOD strike takes out 1 tile, a larger tile will expose a larger part of the hull. which would mean that smaller tiles are safer. Same if one falls off. What am I missing?
Let's says for discussion both a large and small tile take a hit dead center. The smaller tile would put the impact closer to any edge percentage wise relative a larger one and greater chance of failure in terms of crack propagation or fracture... The larger tile may be able to absorb the impact energy shock through the material and disperse it over a greater surface and volume before a total failure...
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: edzieba on 06/28/2020 11:53 am
A larger tile is also a higher aspect ratio object, with a larger bonded area compared to a smaller tile. The same point impact on either time would be more likely to delaminate a small tile than a larger one. Whether you expose a small or large area is somewhat moot, a hole in your TPS is a hole in your TPS, and Dream Chaser has no thick steel plates behind the TPS to prevent LoM.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: john smith 19 on 06/28/2020 12:18 pm
I see they are placing temporary spacers between the tiles during application. I wonder if the gaps will be left open.

As it's launched inside a fairing they won't have to worry about rainwater getting in there and/or freezing.

Anyone know if the carbon fiber structure of Dream Chaser should experience more or less thermal expansion than the Shuttle's Aluminum body?
Good question. I'd expect quite a bit less. The ratio of TCE's of the shuttles aluminum skin to tiles was about 3:1

I've never really understood how anyone could look at that statement, knowing that one layer is ductile and the other very brittle and not conclude that this was going to have some issues. Although the contractor obviously did.  :(
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: xyv on 07/02/2020 12:42 am
I notice (and it's not surprising given the basic shape) that Dream Chaser still has to be covered in what appear to be individually designed and numbered tiles.  This means that any damage has to have a dedicated replacement.  While I grant that modern fabrication techniques may alleviate that, it still complicates logistics.

Watching the experimentation going on in Boca Chica, I see size, bonding and variations in miss-alignment tests going on in the background of all of the mainstream development.  This has really got to be one of the key issues to solve with re-usable reentry vehicles.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Rocket Science on 07/02/2020 01:48 am
I notice (and it's not surprising given the basic shape) that Dream Chaser still has to be covered in what appear to be individually designed and numbered tiles.  This means that any damage has to have a dedicated replacement.  While I grant that modern fabrication techniques may alleviate that, it still complicates logistics.

Watching the experimentation going on in Boca Chica, I see size, bonding and variations in miss-alignment tests going on in the background of all of the mainstream development.  This has really got to be one of the key issues to solve with re-usable reentry vehicles.
I wouldn't worry too much about replacement tiles as each is numbered so with a press of a button a new tile is CNC machined...
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: TrevorMonty on 07/02/2020 03:03 am
They would makes spares of each.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: penguin44 on 07/02/2020 05:11 am
What's the refurbishment time vs shuttle? I think one of main reasons for lower flight rate was tiles. Obviously dc is smaller and not exactly a similar comparison.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: mn on 07/02/2020 03:16 pm
It was asserted that the differences between individual tiles would make it more difficult to manage replacements.

The response was that the differences between individual tiles is handled automatically by computer.

The coating, baking, etc. is the same process for any shape.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Lee Jay on 07/02/2020 03:39 pm
DC has fewer tiles, the tiles are improved, and it's launched in a debris-free environment.  From the beginning, they've claimed this reduces re-use cycle effort by a factor of 10 or more compared to Shuttle, at least with regards to the TPS.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Comga on 07/16/2020 05:34 am
Quote
“The current Shooting Star is already designed with significant capabilities for an orbital outpost and by adding only a few components we are able to meet Department of Defense needs.” said former NASA space shuttle commander and retired USAF pilot Steve Lindsey, now senior vice president of strategy for SNC’s Space Systems business area.

So what are these "Department of Defense needs"?
A large pressurized volume?
Significant electrical power?
Inconvenient external attachments.
No return capability.
What differentiates a free-flying Shooting Star from other spacecraft buses, including ones with long track records?

Somehow there wasn't equivalent enthusiasm when DragonLab was announced, and it had much of these attributes, plus return capacity, plus flight history.
The "adding only a few components" made sense for RocketLab's Photon, but less so for SNC.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: rayleighscatter on 07/16/2020 10:56 pm

What differentiates a free-flying Shooting Star from other spacecraft buses, including ones with long track records?



A DoD contract.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: edzieba on 07/17/2020 11:08 am
So what are these "Department of Defense needs"?
Detailed in this thread (https://forum.nasaspaceflight.com/index.php?topic=48491.0)
Quote
Minimum Desired Specifications

* Internal volume: 1 m3
* Payload capacity: 80 kg
* Power (continuous): 1 kW
* Communications: 100 kbps
* Pressurization: 0 to 1 Atmosphere
[...]
Desired future capabilities (available as options for initial or future implementation) include:

* Common berthing mechanism
* In-space assembly using one or more robotic manipulators and interfaces accepting standard flight fixtures
* Temporary or permanent attachment to other similar modular outposts (manned or unmanned)
* Servicing or re-provisioning to extend flight operations for a longer duration
* Human-rating
* Orbit transfer
* Radiation hardening for beyond LEO applications
* Other unique features contributing to national security or defense. 
Quote
Somehow there wasn't equivalent enthusiasm when DragonLab was announced, and it had much of these attributes, plus return capacity, plus flight history.
DragonLab was a "we're doing this for our own stuff, but you can come along too I guess". Orbital Outpost is a customer-first mission built at the request of the customer (albeit as a modification of an existing system).
It would be interesting to see who else bid for OO and what it was they offered, but that seems unlikely to be disclosed.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: ChrisWilson68 on 07/17/2020 04:54 pm
So what are these "Department of Defense needs"?
Detailed in this thread (https://forum.nasaspaceflight.com/index.php?topic=48491.0)
Quote
Minimum Desired Specifications

* Internal volume: 1 m3
* Payload capacity: 80 kg
* Power (continuous): 1 kW
* Communications: 100 kbps
* Pressurization: 0 to 1 Atmosphere
[...]
Desired future capabilities (available as options for initial or future implementation) include:

* Common berthing mechanism
* In-space assembly using one or more robotic manipulators and interfaces accepting standard flight fixtures
* Temporary or permanent attachment to other similar modular outposts (manned or unmanned)
* Servicing or re-provisioning to extend flight operations for a longer duration
* Human-rating
* Orbit transfer
* Radiation hardening for beyond LEO applications
* Other unique features contributing to national security or defense. 
Quote
Somehow there wasn't equivalent enthusiasm when DragonLab was announced, and it had much of these attributes, plus return capacity, plus flight history.
DragonLab was a "we're doing this for our own stuff, but you can come along too I guess". Orbital Outpost is a customer-first mission built at the request of the customer (albeit as a modification of an existing system).
It would be interesting to see who else bid for OO and what it was they offered, but that seems unlikely to be disclosed.

No, DragonLab wasn't "we're doing this for our own stuff".  SpaceX was not planning to do any of its own experiments on DragonLab.  It was purely for the customers.  There apparently weren't enough customers.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: BrightLight on 07/17/2020 05:18 pm
from:
https://www.sncorp.com/press-releases/dod-selects-snc-to-design-develop-unmanned-orbital-outpost-prototype/

SPARKS, Nev., July 14, 2020 – Sierra Nevada Corporation (SNC), the global aerospace and national security leader owned by Eren and Fatih Ozmen, was awarded a contract to repurpose SNC’s Shooting Star transport vehicle as a proposed commercial solution for an Unmanned Orbital Outpost – essentially a scalable, autonomous space station for experiments and logistics demonstrations – by the Defense Innovation Unit (DIU). SNC’s Shooting Star transport vehicle serves as the core structure for the proposed design....

“The current Shooting Star is already designed with significant capabilities for an orbital outpost and by adding only a few components we are able to meet Department of Defense needs.” said former NASA space shuttle commander and retired USAF pilot Steve Lindsey, now senior vice president of strategy for SNC’s Space Systems business area. “We are proud to offer our transport vehicle to DoD as a free-flying destination for experimentation and testing, expanding beyond its current payload service capabilities for Dream Chaser cargo missions.”

No information on what was actually proposed or milestones at this time of posting.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: ChrisWilson68 on 07/17/2020 05:39 pm
I'd like to know the procurement process that led to this contract.  Was it openly competed?  Why didn't we hear anything about it until it was already awarded?
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: JEF_300 on 07/17/2020 06:36 pm
I don't know about you all, but the first time I heard about this Orbital Outpost, I couldn't finish the article, because I couldn't focus on it over the little voice in the back of my head that was screaming "MOL! MOL!".

There are obviously big differences. For one, MOL was, primarily, supposed to be for surveillance. I don't know why you would need a cubic meter of livable volume on a spy satellite in the 2020s though. MOL needed it because it was supposed to be crewed, which obviously, this isn't. It is crew-accessible though; note the 'nice-to-have' requirements for a CBM and human-rating, and the one in the render definitely has a port of some sort.

We're all wondering why the DoD wants a small livable module in LEO in the 2020s. Presumably, the first step should be to look at what things other than surveillance they were going to do with a small livable module in LEO in the 1960s.

Mind you, I don't actually know what those things ARE. Whenever MOL has come up in the past, I've always been too enamored with the idea of Gemini flying longer to worry about the laboratory part. I assume there are people on here who know though.

Also, for context, has everything about MOL been declassified?
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: ChrisWilson68 on 07/17/2020 06:53 pm
If this was a no-bid contract award, I wouldn't be surprised to see a lawsuit from SpaceX about it and/or an investigation by DoD Inspector General's office.

SNC has a history of heavy spending on lobbying and campaign contributions that have allegedly led to lucrative contracts.  SpaceX has a history of filing suit when a contract was awarded to a rival in a way that could be seen as biased against SpaceX.

On the face of it, SNC is not the most obvious company to get a contract for an uncrewed orbital outpost with a habitable volume.  They have less of a track record of flying something similar than numerous other companies -- SpaceX with both cargo and crew Dragon, Northrup Grumman with Cygnus, Boeing with Starliner, and Lockheed Martin with Orion.  All of those companies would on the face of it have much more relevant proven experience.

Perhaps there are factors we don't know that make it appropriate for SNC to have received this contract.  If there are, they don't seem to be public.  As a taxpayer, I'd like to know what they are.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: ncb1397 on 07/17/2020 08:33 pm
I'd like to know the procurement process that led to this contract.  Was it openly competed?  Why didn't we hear anything about it until it was already awarded?

Information on this forum existed for the last year. You must have missed it.

https://forum.nasaspaceflight.com/index.php?topic=48491.0
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: TrevorMonty on 07/17/2020 11:38 pm


If this was a no-bid contract award, I wouldn't be surprised to see a lawsuit from SpaceX about it and/or an investigation by DoD Inspector General's office.

SNC has a history of heavy spending on lobbying and campaign contributions that have allegedly led to lucrative contracts.  SpaceX has a history of filing suit when a contract was awarded to a rival in a way that could be seen as biased against SpaceX.

On the face of it, SNC is not the most obvious company to get a contract for an uncrewed orbital outpost with a habitable volume.  They have less of a track record of flying something similar than numerous other companies -- SpaceX with both cargo and crew Dragon, Northrup Grumman with Cygnus, Boeing with Starliner, and Lockheed Martin with Orion.  All of those companies would on the face of it have much more relevant proven experience.

Perhaps there are factors we don't know that make it appropriate for SNC to have received this contract.  If there are, they don't seem to be public.  As a taxpayer, I'd like to know what they are.

SNC are private company like SpaceX but with extensive history of producing reliable HW that has flown on most planetary missions and lots of GEO satellites. SpaceX has yet to operate any HW in space for more than few months and not in BLEO environment.
While freeflyer is human rated it won't be providing any life support, that is responsible of any visiting crew vehicle.

Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: ChrisWilson68 on 07/18/2020 12:07 am


If this was a no-bid contract award, I wouldn't be surprised to see a lawsuit from SpaceX about it and/or an investigation by DoD Inspector General's office.

SNC has a history of heavy spending on lobbying and campaign contributions that have allegedly led to lucrative contracts.  SpaceX has a history of filing suit when a contract was awarded to a rival in a way that could be seen as biased against SpaceX.

On the face of it, SNC is not the most obvious company to get a contract for an uncrewed orbital outpost with a habitable volume.  They have less of a track record of flying something similar than numerous other companies -- SpaceX with both cargo and crew Dragon, Northrup Grumman with Cygnus, Boeing with Starliner, and Lockheed Martin with Orion.  All of those companies would on the face of it have much more relevant proven experience.

Perhaps there are factors we don't know that make it appropriate for SNC to have received this contract.  If there are, they don't seem to be public.  As a taxpayer, I'd like to know what they are.

SNC are private company like SpaceX but with extensive history of producing reliable HW that has flown on most planetary missions and lots of GEO satellites. SpaceX has yet to operate any HW in space for more than few months and not in BLEO environment.
While freeflyer is human rated it won't be providing any life support, that is responsible of any visiting crew vehicle.

Building components for planetary missions is a whole lot less relevant than building something similar like Dragon or Cygnus.  This contract is for an LEO  outpost.

And the claim that SpaceX has yet to operate any hardware in space for more than a few months is false.  Some of the Starlink satellites have been operating for more than a year.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: JEF_300 on 07/20/2020 12:03 am
It occurs to me that this is supposed to be, to quote the original post, "DISCUSSION thread for SNC's Dream Chaser as it progresses to the end of CCDev-2."

Considering that the DoD's Orbital Outpost has nothing to do with CCDev-2, this is probably outside of that mandate. The OO probably deserves it's own thread anyway; in fact, one was already linked to up-thread. https://forum.nasaspaceflight.com/index.php?topic=48491.0 (https://forum.nasaspaceflight.com/index.php?topic=48491.0)

I leave it to the mods to decided whether or not that is a distinction that should be enforced, and whether or not they want to moves posts around.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: ChrisWilson68 on 07/20/2020 10:14 pm
SpaceNews has an article with more news about SNC's contract to re-purpose a part of the DreamChaser project as an orbital outpost for the DoD:

https://spacenews.com/three-companies-studying-orbital-outpost-space-station-concepts-for-defense-department/

It turns out that the SNC news release was very, very misleading.

It wasn't actually a contract to build an orbital outpost.  It was a contract to do a study on what it would take to make Shooting Star into an orbital outpost.  And SNC was just one of three companies that received such study awards.

SNC gets $439,100 for this contract.  Nanoracks gets $389,900 for a similar contract.  A company called Arkisys gets $366,000.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: GWH on 07/21/2020 10:26 pm
SA company called Arkisys gets $366,000.

https://arkisys.com/

Another mysterious space startup with a really vague website. They show some kind of orbital vehicle and then a graphic of a giant space station. The space station also appears to have a giant beam of energy shooting past it... hope no one gets hurt!
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: ChrisWilson68 on 07/21/2020 10:35 pm
SA company called Arkisys gets $366,000.

https://arkisys.com/

Another mysterious space startup with a really vague website. They show some kind of orbital vehicle and then a graphic of a giant space station. The space station also appears to have a giant beam of energy shooting past it... hope no one gets hurt!

If you're playing space buzzword bingo, you hit the jackpot on that site.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: yg1968 on 07/22/2020 01:55 am
Cool graphic of DC's history:

https://twitter.com/PranavGayatri/status/1285574682717024257
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: ChrisWilson68 on 07/22/2020 02:08 am
Cool graphic of DC's history:

https://twitter.com/PranavGayatri/status/1285574682717024257

Funny how that version of history conveniently leaves out the M2-F1 and HL-10, which were US lifting body prototypes that flew in 1963 and 1966 respectively.  But sure, just paint those out of history and only list Russian models that came later.

https://en.wikipedia.org/wiki/NASA_M2-F1

https://en.wikipedia.org/wiki/Northrop_HL-10
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Lars-J on 07/22/2020 05:46 am
Funny how that version of history conveniently leaves out the M2-F1 and HL-10, which were US lifting body prototypes that flew in 1963 and 1966 respectively.  But sure, just paint those out of history and only list Russian models that came later.

https://en.wikipedia.org/wiki/NASA_M2-F1

https://en.wikipedia.org/wiki/Northrop_HL-10

Oh there was plenty of "borrowing" going on in both directions. But it is fair to say that DC looks a lot more like BOR-4 than M2-F1 or HL-10.

And SNC has never denied that either: https://www.denverpost.com/2016/02/26/sierra-nevadas-dream-chaser-derived-from-lost-soviet-space-plane/

Quote
In 2005, Sirangelo took a trip to Russia and visited with some of the engineers who worked on the BOR-4. He told them that their idea lived on. They were stunned, and had no idea that their invention had been resurrected, as the website Ars Technica has reported.

Sirangelo promised that when the Dream Chaser flew, it would carry a list of the names of the Russian engineers along with people at NASA who worked on the HL-20 program.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Steven Pietrobon on 07/22/2020 06:30 am
That graph also ignores the SV-5D PRIME lifting bodies launched by the US from 1966 to 1967.

https://www.nationalmuseum.af.mil/Visit/Museum-Exhibits/Fact-Sheets/Display/Article/195893/sv-5d-prime-lifting-body/
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Robotbeat on 07/24/2020 02:01 pm
Funny how that version of history conveniently leaves out the M2-F1 and HL-10, which were US lifting body prototypes that flew in 1963 and 1966 respectively.  But sure, just paint those out of history and only list Russian models that came later.

https://en.wikipedia.org/wiki/NASA_M2-F1

https://en.wikipedia.org/wiki/Northrop_HL-10

Oh there was plenty of "borrowing" going on in both directions. But it is fair to say that DC looks a lot more like BOR-4 than M2-F1 or HL-10.

And SNC has never denied that either: https://www.denverpost.com/2016/02/26/sierra-nevadas-dream-chaser-derived-from-lost-soviet-space-plane/

Quote
In 2005, Sirangelo took a trip to Russia and visited with some of the engineers who worked on the BOR-4. He told them that their idea lived on. They were stunned, and had no idea that their invention had been resurrected, as the website Ars Technica has reported.

Sirangelo promised that when the Dream Chaser flew, it would carry a list of the names of the Russian engineers along with people at NASA who worked on the HL-20 program.

That’s a pretty great story!

I love it.

I feel like the world is slipping back into another Cold War with geopolitical tensions, mistrust, reduced cooperation. We shouldn’t let some of our terrible leaders distract from mutual respect among our engineers and scientists. Realizing and respecting our fellow humans is what will get us through this next Cold War without destroying each other.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: yg1968 on 07/31/2020 06:38 pm
As part of the Artemis Accords, the current administration is seeking to broaden international partnerships to other nations, in addition to the current ISS partners. Russia has been invited to participate in Gateway but it has refused to do so (for now, at least). Many believe that this is actually because of Roscomos' shrinking budget rather than any diplomatic reason. 

Quote from: Axios
Roscosmos's 2020 budget is the equivalent of roughly $1.7 billion; in 2014, it was about $5 billion.

https://www.axios.com/russia-space-program-spacex-e79cf40e-3a52-4436-b27a-cc864b8938a9.html
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: FutureSpaceTourist on 10/11/2020 02:48 pm
Quote
Inside Sierra Nevada Corp's space plans, from the reusable 'Dream Chaser' to inflatable habitats
PUBLISHED SUN, OCT 11 2020 6:57 AM EDT
Michael Sheetz
@THESHEETZTWEETZ

KEY POINTS

Private contractor Sierra Nevada Corporation (SNC) invested heavily in its space systems division, especially as it sees NASA and other companies building infrastructure in orbit.

The crown jewel of SNC's space portfolio is Dream Chaser: A reusable spacecraft that is built to launch atop a traditional rocket and land on a runway like an airplane.

"We view the Dream Chaser as something that eventually in low Earth orbit will be providing transportation, logistics and crew for everybody," Steve Lindsey, SNC's senior vice president of strategy space systems, told CNBC.

https://www.cnbc.com/amp/2020/10/10/sierra-nevada-corporations-space-plan-dream-chaser-nasas-artemis-and-more.html
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Coastal Ron on 10/11/2020 03:16 pm
Great article, and proof that Sierra Nevada Corporation (SNC) is a company that could be very important as we try to expand humanity out into space.

And as much as I love the SpaceX Starship, SNC's Dream Chaser still has a place in our space future, since it can return humans and cargo to places on Earth that Starship can't reach.

SNC is a privately held company (https://en.wikipedia.org/wiki/Sierra_Nevada_Corporation), and that gives them the advantage to focus on what they want, without having to worry about uninvolved investors. I wish them well.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: TrevorMonty on 10/11/2020 11:42 pm
Quote
Inside Sierra Nevada Corp's space plans, from the reusable 'Dream Chaser' to inflatable habitats
PUBLISHED SUN, OCT 11 2020 6:57 AM EDT
Michael Sheetz
@THESHEETZTWEETZ

KEY POINTS

Private contractor Sierra Nevada Corporation (SNC) invested heavily in its space systems division, especially as it sees NASA and other companies building infrastructure in orbit.

The crown jewel of SNC's space portfolio is Dream Chaser: A reusable spacecraft that is built to launch atop a traditional rocket and land on a runway like an airplane.

"We view the Dream Chaser as something that eventually in low Earth orbit will be providing transportation, logistics and crew for everybody," Steve Lindsey, SNC's senior vice president of strategy space systems, told CNBC.

https://www.cnbc.com/amp/2020/10/10/sierra-nevada-corporations-space-plan-dream-chaser-nasas-artemis-and-more.html
Couple surprises in this article.
Working unpressurized and pressurized rovers with other partners.
Want to use Shoot Star to transport crew from LEO to moon (lunar orbit I assume) and back. Will need refuel at moon for return trip, my guess it will may use Dynetic's lander tankers.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: GWH on 10/12/2020 01:19 am
They mention an app in the article to learn about Dreamchaser.  I couldn't find a link to this in the article or anywhere on the SNC website.  I hope they share it.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Rocket Science on 10/12/2020 01:42 pm
That graph also ignores the SV-5D PRIME lifting bodies launched by the US from 1966 to 1967.

https://www.nationalmuseum.af.mil/Visit/Museum-Exhibits/Fact-Sheets/Display/Article/195893/sv-5d-prime-lifting-body/
Absolutely Steven as well as the successful piloted X-24A program...
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: adrianwyard on 10/13/2020 07:26 pm
In this image from recent wind tunnel tests the thrusters at the rear are angled inwards. They are also shown angled this way in recent animations. Why would that be? My guess is they are primarily for yaw control (and only once the cargo module has been jettisoned), but wouldn't the thrusters under the wings already cover that?
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: edzieba on 10/14/2020 02:44 pm
Possibly to minimise RCS impingement on control surfaces during re-entry, seen in this presentation on simulation and wind-tunnel testing of Dream Chaser[/ur]. (https://www.nas.nasa.gov/SC19/demos/demo1.html)
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Nomadd on 10/14/2020 03:21 pm
Possibly to minimise RCS impingement on control surfaces during re-entry, seen in this presentation on simulation and wind-tunnel testing of Dream Chaser[/ur].
 (https://www.nas.nasa.gov/SC19/demos/demo1.html)
I was thinking more of to avoid messing up wing/control surface performance by keeping thruster exhaust out of the airflow from the wings. But, I'm not sure if they'd ever use thrusters at subsonic speeds.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: adrianwyard on 10/14/2020 04:09 pm
Fascinating. The thruster plume/wing aerodynamics interaction is obvious in retrospect :-) I wonder if they'll delete the under-wing thrusters entirely, or just work around this interaction at certain speeds.

The PowerPoint presentation linked on that web page is worth a look; it has animations of the thruster plume, and mentions they will be doing extensive imagery on it's first first re-entry.

https://www.nas.nasa.gov/upload/files/sc19presentations/NASA_SC19_Jeffries_Demo.ppsx
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: vt_hokie on 11/18/2020 12:32 am
Do we have any sense of what the latest launch slip means for vehicle completion and rollout?  Will we see a completed DC vehicle a year or more ahead of launch?
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: adrianwyard on 11/22/2020 09:25 pm
Fascinating. The thruster plume/wing aerodynamics interaction is obvious in retrospect :-) I wonder if they'll delete the under-wing thrusters entirely, or just work around this interaction at certain speeds.

The PowerPoint presentation linked on that web page is worth a look; it has animations of the thruster plume, and mentions they will be doing extensive imagery on it's first first re-entry.

https://www.nas.nasa.gov/upload/files/sc19presentations/NASA_SC19_Jeffries_Demo.ppsx
I just noticed the Soviet-era Spiral lifting body design also had inward pointing yaw thrusters. Here's a nice recent illustration of that airframe that clearly shows them on the rear:
https://twitter.com/Nick_Stevens_Gr/status/1330478748064493568?s=20
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: edzieba on 11/23/2020 08:29 am
For pure uncoupled yaw, it also makes sense from a cosine loss perspective: simplify your vehicle down to a point mass at CoM with one yaw thruster stuck out on a strut. Which way would that thruster need to point in order to provide the most effective yaw impulse?
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Hog on 11/30/2020 04:34 pm
That graph also ignores the SV-5D PRIME lifting bodies launched by the US from 1966 to 1967.

https://www.nationalmuseum.af.mil/Visit/Museum-Exhibits/Fact-Sheets/Display/Article/195893/sv-5d-prime-lifting-body/
Absolutely Steven as well as the successful piloted X-24A program...
X-24A pilots:
Jerauld R. Gentry – 13 flights
John A. Manke – 12 flights
Cecil W. Powell – 3 flights

Martin X-23A PRIME (Precision Reentry Including Maneuvering reEntry) (SV-5D)
 "was a small lifting-body re-entry vehicle tested by the United States Air Force in the mid-1960s.X-23 PRIME was developed to study the effects of maneuvering during re-entry of Earth's atmosphere, including cross-range maneuvers up to 710 statute miles (1143 km) from the ballistic track."  For comparison, the Space Shuttle Orbiter Vehicles attained a cross range of 1100 nautical miles/1266 statute miles or 2037 kms.

The theories of blunt vs. sharp type noses were studied, the "blunt" nose design was used for space shuttle.

The same people that did the Gemini ejector seats, Weber Aircraft, did the ejector seats for Lunar Landing Trainer Vehicle(LLTV), NASA lifting bodies M2F2, HL-10 and X-24 as well as the Gemini Spacecraft (and the Apollo 3-man Crew Couch system

attachments
1) X23 PRIME vehicle
2) Martin Marietta vehicle X24a vehicle
3) X24 presentation Miles Miller JHU Odyssey Program, September 27, 2012  PDF
4) Northrop HL-10
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: MySDCUserID on 12/17/2020 10:23 pm
Given Dragon 2's undebatable success, and Starship's amazing progress, what purpose is Dream Chaser going to serve?  I feel like this vehicle is just going to join the list of other vehicles made obsolete once Starship archives its full greatness.  Are SNC just throwing money into a hole at this point? 
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Welsh Dragon on 12/18/2020 09:32 am
Given Dragon 2's undebatable success, and Starship's amazing progress, what purpose is Dream Chaser going to serve?  I feel like this vehicle is just going to join the list of other vehicles made obsolete once Starship archives its full greatness.  Are SNC just throwing money into a hole at this point?
Redundancy. And Starship is only successful when it is successful. No guarantees at this point (although I suspect it will be from a technical standpoint and probably will be from an business one).
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Bean Kenobi on 12/18/2020 12:49 pm
Given Dragon 2's undebatable success, and Starship's amazing progress, what purpose is Dream Chaser going to serve?  I feel like this vehicle is just going to join the list of other vehicles made obsolete once Starship archives its full greatness.  Are SNC just throwing money into a hole at this point? 

Not the same market at all : Dream Chaser is for cargo only to ISS, Dragon is for cargo to ISS (plus crew version), and Starship is (as of today) a project for cargo and crew to Moon and Mars.

For cargo to ISS, yes it's a matter of redundancy of Dragon and Cygnus. With the point that atmospheric reentry and landing on Dream Chaser is expected to be smoother than on Dragon for sensible experiments.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Cherokee43v6 on 12/18/2020 01:20 pm
Given Dragon 2's undebatable success, and Starship's amazing progress, what purpose is Dream Chaser going to serve?  I feel like this vehicle is just going to join the list of other vehicles made obsolete once Starship archives its full greatness.  Are SNC just throwing money into a hole at this point?

A couple rules of thumb:

Nothing is obsolete until it actually is obsolete.
In this case, Dreamchaser is a companion vehicle to D2Cargo, not a competitor.  To assume Starship (cool as it is) will be a success is the worst of chicken counting in the egg room.

Just because something has been superseded does not mean that it does not continue to be useful.

ie The battleship became obsolete in 1942 yet it continued to play a vital role in naval planning and operations until the mid 1990s.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: AlexP on 12/18/2020 02:06 pm
They have a contract with NASA for multiple missions, obviously they aren't throwing money into a pit. The more reusable spacecraft, the better, as far as I'm concerned.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Rocket Science on 12/18/2020 02:14 pm
Nothing can compete with Dream Chaser for the low g entry and shock sensitive experiments returning from ISS... At least not at this time...
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: JAFO on 12/19/2020 07:33 pm
Not the same market at all : Dream Chaser is for cargo only to ISS, Dragon is for cargo to ISS (plus crew version), and Starship is (as of today) a project for cargo and crew to Moon and Mars.
Remember that SNC is also developing cargo DC with an eye to upgrade to human rated. Odds are that one day an astronaut will develop a life threatening medical emergency, and the low-G reentry plus cross range capability to land at almost any major airport in a timely matter could make the difference between life and death.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: john smith 19 on 12/20/2020 06:56 pm
Given Dragon 2's undebatable success, and Starship's amazing progress, what purpose is Dream Chaser going to serve?  I feel like this vehicle is just going to join the list of other vehicles made obsolete once Starship archives its full greatness.  Are SNC just throwing money into a hole at this point?
Right now DC is exactly at the same level as SS.

Nowhere near LEO.  :(

Let's see where they are both at this time next year.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Ulmo on 01/29/2021 06:14 pm
SpaceX should offer to launch the Dream Chaser for free for the first few launches.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: whitelancer64 on 01/29/2021 06:30 pm
SpaceX should offer to launch the Dream Chaser for free for the first few launches.

Why would they do that??? Falcon Heavy is not free to launch.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: TrevorMonty on 01/30/2021 09:27 am
SpaceX should offer to launch the Dream Chaser for free for the first few launches.
Launch the competitions cargo vehicle for free. Why?

Sent from my SM-G570Y using Tapatalk

Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: M.E.T. on 02/09/2021 03:36 am
Let’s talk about the most important metrics for competitiveness in the new space business - what is the cost per launch and cost per kg to LEO we are looking at for Dreamchaser?
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: leovinus on 04/01/2021 11:16 pm
In the light of the SNC LEO Space station (https://forum.nasaspaceflight.com/index.php?topic=53484.msg2214119#msg2214119) announcement, I was wondering about DreamChaser launch vehicles. To put several habitats, several stations, private astronauts, regular flights up in LEO, what LV(s) will they use? Just my opinion, but it seems that the potential manifest would be too large to be served by Vulcan only?
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: RonM on 04/01/2021 11:39 pm
In the light of the SNC LEO Space station (https://forum.nasaspaceflight.com/index.php?topic=53484.msg2214119#msg2214119) announcement, I was wondering about DreamChaser launch vehicles. To put several habitats, several stations, private astronauts, regular flights up in LEO, what LV(s) will they use? Just my opinion, but it seems that the potential manifest would be too large to be served by Vulcan only?

New Glenn, Starship, whatever available launch vehicle that can get it in the right orbit.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: adrianwyard on 04/02/2021 01:47 am
Hi all, SNC have posted a video of yesterday's Press Briefing:

https://vimeo.com/531507529

Steve Lindsey spoke about their plans for a (new) abort capability at 49:46.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: whitelancer64 on 04/02/2021 01:54 am
Hi all, SNC have posted a video of yesterday's Press Briefing:

*snip video*

Steve Lindsey spoke about their plans for a (new) abort capability at 49:46.

That sounds a lot like the (old) abort capability, just firing the main engines.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: adrianwyard on 04/02/2021 02:31 am
True, but a major change from the Cargo Dream Chaser they are currently building which only has RCS.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: TrevorMonty on 04/02/2021 11:05 am
True, but a major change from the Cargo Dream Chaser they are currently building which only has RCS.
None of cargo vehicles carry abort engines.

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Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: adrianwyard on 04/02/2021 03:48 pm
True, but a major change from the Cargo Dream Chaser they are currently building which only has RCS.
None of cargo vehicles carry abort engines.

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Correct. I'm not sure what point you are making.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: JAFO on 04/10/2021 07:48 pm
Question: if they are planning to launch the eventual crewed DC unfaired, why go to the expense of designing a wing unfolding mechanism, and adding the weight of it plus the weight of the fairing?

Thanks
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: adrianwyard on 04/10/2021 08:44 pm
It's a fair question. One reason is the cargo module can support much larger externally attached items when inside a fairing. That said, the graphics of the crewed version still show external payloads on the Shooting Star. Artistic oversight - just reusing 3D files on hand?
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: TrevorMonty on 04/10/2021 09:01 pm
I'm surprised they will use shooting star with crew version, need to separate two in case of LAS being activated.

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Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Athelstane on 04/10/2021 11:16 pm
It's a fair question. One reason is the cargo module can support much larger externally attached items when inside a fairing. That said, the graphics of the crewed version still show external payloads on the Shooting Star. Artistic oversight - just reusing 3D files on hand?

Yeah, I was wondering about that myself. Probably an artistic oversight, but who knows?
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Sesquipedalian on 04/12/2021 04:20 pm
Question: if they are planning to launch the eventual crewed DC unfaired, why go to the expense of designing a wing unfolding mechanism, and adding the weight of it plus the weight of the fairing?

Launching DC inside a fairing solves several major problems, including providing more space for external cargo and removing the complicated air loads analysis.  It only introduces one* problem - wing unfolding - which is very minor in comparison because deployment mechanisms are well studied and mature.

*Or two problems if you count weight - but the additional weight is really inconsequential, especially since the fairing is jettisoned early in the launch.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Nascent Ascent on 05/13/2021 05:41 am
It's a shame that DC doesn't fly on a reusable booster. Rapid reuse and turnaround compared to Dragon are the main advantages. No boats, seawater, nasty propellants,

DC's reuse seems more in line with the SpaceX philosophy. 

Technically, could Falcon 9 carry DC or would it require FH?
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: ncb1397 on 05/13/2021 05:52 am
It's a shame that DC doesn't fly on a reusable booster. Rapid reuse and turnaround compared to Dragon are the main advantages. No boats, seawater, nasty propellants,

DC's reuse seems more in line with the SpaceX philosophy. 

Technically, could Falcon 9 carry DC or would it require FH?

With 5.5 metric tons of cargo? Almost certainly Falcon Heavy. And the extended fairing. If it was compatible with F9R, Dream Chaser would likely be using a 2 solid Vulcan with a payload of 16.1 t to ISS inclination instead of the 4 solid Vulcan with payload of 21 t.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Robotbeat on 05/13/2021 05:59 am
It's a shame that DC doesn't fly on a reusable booster. Rapid reuse and turnaround compared to Dragon are the main advantages. No boats, seawater, nasty propellants,

DC's reuse seems more in line with the SpaceX philosophy. 

Technically, could Falcon 9 carry DC or would it require FH?
F9 is plenty sufficient for DC.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Asteroza on 05/14/2021 12:26 am
It's a shame that DC doesn't fly on a reusable booster. Rapid reuse and turnaround compared to Dragon are the main advantages. No boats, seawater, nasty propellants,

DC's reuse seems more in line with the SpaceX philosophy. 

Technically, could Falcon 9 carry DC or would it require FH?

With 5.5 metric tons of cargo? Almost certainly Falcon Heavy. And the extended fairing. If it was compatible with F9R, Dream Chaser would likely be using a 2 solid Vulcan with a payload of 16.1 t to ISS inclination instead of the 4 solid Vulcan with payload of 21 t.

Would that be F9H expendable modes, or full F9HR including core stage?
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: ncb1397 on 05/14/2021 12:30 am
It's a shame that DC doesn't fly on a reusable booster. Rapid reuse and turnaround compared to Dragon are the main advantages. No boats, seawater, nasty propellants,

DC's reuse seems more in line with the SpaceX philosophy. 

Technically, could Falcon 9 carry DC or would it require FH?

With 5.5 metric tons of cargo? Almost certainly Falcon Heavy. And the extended fairing. If it was compatible with F9R, Dream Chaser would likely be using a 2 solid Vulcan with a payload of 16.1 t to ISS inclination instead of the 4 solid Vulcan with payload of 21 t.

Would that be F9H expendable modes, or full F9HR including core stage?

FH with recovering boosters and the core is supposed to be able to carry 30 metric tons to LEO (per SpaceX). Now, the Vulcan configuration that Dream Chaser uses can do 21 t to ISS inclination which is a bit harder than just any old LEO orbit that is most convenient for the vehicle. While recovery of the core stage has proven a bit more difficult than expected, but there appears to be significant margin increasing the odds that you can recover all 3 cores (enough margin to cover carrying the heavier fairing that is likely required as well).
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: GreenShrike on 07/08/2021 09:23 pm
(Post originally in "Re: ULA Vulcan Launch Vehicle - Business Case/Competition/Alternatives Discussion" thread)

Sierra Nevada company is still sore over losing "their" spot on CCP to SpaceX. They were absolutely convinced that the CCtCAP winners would be themselves and Boeing. So when "their" spot went to SpaceX instead, they took that defeat personally. They're still not over it. Which is why they fought so hard to get back into the game with CRS-2.

Up until now I had assumed DC on Falcon to be a fairly obvious pairing outside of NASA's redundancy requirements, but this grudge has got me wondering if, like Amazon, Sierra is willing to sacrifice money to snub SpaceX.

While it's easy to see DreamChaser launching on ULA for CRS2 given NASA's dissimilar redundancy preferences and that, ultimately, it's NASA paying for DC's booster, not Sierra. As such, using ULA's launch services currently costs Sierra nothing.

However, I think it fairly obvious that Crew Dragon's commercial success, winning Inspiration 4 and several Axiom missions, has a lot to do with its pricing with respect to Starliner, currently the only alternative (American, anyway). While NASA can bear the expense of supporting Starliner, a commercial entity looking to fly would have a harder time justifying spending additional millions on a more expensive solution that confers no obvious benefit over a less expensive option -- especially since NASA is already helpfully guaranteeing the more expensive solution will be sticking around, just in case.


One of the reasons Starliner costs more to fly is its launcher costs more than Dragon's -- and the same currently applies to Sierra.


Though DC's architecture means it has advantages over Dragon, are they sufficient to allow Sierra roll the dice on forcing DC to be bundled with Vulcan or the even pricier Atlas 5 and risk losing flights to a cheaper Dragon?

Or are they simply hoping (along with everyone else) that New Glenn just gets flying soonest and can accommodate everyone who wants both a) cheap and b) non-SpaceX rides? To me, this seems fairly risky considering the uncertainty around New Glenn's first flight, and the even greater uncertainly around its subsequent flights.

Or would they go for the "better half the pie than none" approach, forget the grudge and try to co-opt some of SpaceX's cost advantage and easy availability by flying DC on Falcons?
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: TrevorMonty on 07/08/2021 10:25 pm
DC can carry more per launch than Dragon as it has disposable Shooting Star module. This should help with price difference on LVs. The other advantage to using ULA LV is eventually SNC want to fly crew so they can piggy back on work done integrating Atlas with Starliner.



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Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: ncb1397 on 07/09/2021 02:32 am

Or would they go for the "better half the pie than none" approach, forget the grudge and try to co-opt some of SpaceX's cost advantage and easy availability by flying DC on Falcons?

It is perfectly conceivable that the Vulcan pricing they got back was the same or lower than the price they got back from SpaceX.

-Discounted pricing as a launch customer
-Falcon Heavy triple core vs single core Vulcan (with solids)
-Non-standard new fairing (at the time quotes were requested) vs standard fairing
-Non-standard vertical integration (at the time quotes were requested) vs. standard vertical integration
-Non-common vehicle configuration (falcon heavy) vs common vehicle configuration (Vulcan single core).
-SpaceX may have been assuming losing at least one of the Falcon Heavy cores in their pricing given that is the history of all 3 Falcon Heavy launches- same assumption for Vulcan.

edit: to back that up with numbers

1st Vulcan task order: $337 million for 2 launches: $168.5 million
2nd Vulcan task order: $224 million for 2 launches: $112 million

Falcon Heavy STP-2: $160 million
Falcon Heavy USSF-44: combined with NROL-85 and NROL-87, $297 million. Assuming $80 million for the Falcon 9 flights gives a cost of $137 million
Falcon Heavy USSF-52: $130 million.

So, there may not be much of a cost advantage in that case. The other option is to go with Falcon 9 expendable but that may cause a ~1,100 kg hit to payload which at $75,000 per kilogram could hit revenue per flight by ~82-83 million dollars.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: GreenShrike on 07/09/2021 04:30 am
DC can carry more per launch than Dragon as it has disposable Shooting Star module. This should help with price difference on LVs. The other advantage to using ULA LV is eventually SNC want to fly crew so they can piggy back on work done integrating Atlas with Starliner.

True, Dream Chaser has advantages, and Shooting Star is one. However, Shooting Star, as a pressurized spacecraft with deployable solar wings, a couple of actual docking ports, thrusters to provide Dream Chaser with maneuvering capability, and independent free-flying capability, undoubtedly costs more than the considerably simpler Dragon trunk.

As such, I would guess that Shooting Star's capabilities, while pretty cool, are already built into Dream Chaser's price and, further, would tend to increase the Dream Chaser's base costs vis-a-vis Dragon 2, regardless of the cost of either's launch vehicles.

Now, if you need half-a-Cygnus and half-a-Dragon on the same flight (i.e. a mix of both their capabilities that neither alone possesses), the Dream Chaser is obviously your pick.

But for missions where a Dragon would do -- or if you don't need down mass, Cygnus, come to that, as Cygnus was cheaper in CRS2 than Dragon 2 -- a more expensive launch vehicle on top of Dream Chaser's extra capabilities would further inflate Sierra's costs and disadvantage Dream Chaser.

Which brings us back to: does Sierra stick with a more expensive launcher, and trust DC's capabilities to carry her through, or switch to a less expensive launcher to increase DC's chances of winning contracts, even if it gives work to a company Sierra apparently disfavours?

It is perfectly conceivable that the Vulcan pricing they got back was the same or lower than the price they got back from SpaceX.

-Discounted pricing as a launch customer
-Falcon Heavy triple core vs single core Vulcan (with solids)
-Non-standard new fairing (at the time quotes were requested) vs standard fairing
-Non-standard vertical integration (at the time quotes were requested) vs. standard vertical integration
-Non-common vehicle configuration (falcon heavy) vs common vehicle configuration (Vulcan single core).
-SpaceX may have been assuming losing at least one of the Falcon Heavy cores in their pricing given that is the history of all 3 Falcon Heavy launches- same assumption for Vulcan.

Certainly. It's even possible that, going forward, SpaceX either sets or continues to set Falcon's pricing above Vulcan's for Dream Chaser, as either an attempt to capture more profit, or to reduce competition for Dragon's services, or because they genuinely can't undercut Vulcan's pricing (note that I don't particularly believe the latter. ;-) ).

Even so, I was more after Sierra's strategy and point-of-view with regard to potential non-NASA contracts than with SpaceX's POV or potential reasons as to why CRS2 Dream Chaser is flying on Vulcan.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: TrevorMonty on 07/11/2021 11:21 am
Why do you say SNC has grudge against SpaceX?.

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Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Joseph Peterson on 07/12/2021 10:12 am
Why do you say SNC has grudge against SpaceX?.

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My personal opinion is that back in the day anyone who mattered assumed Boeing was the safe choice that would definitely be operational years before anyone else.  This made everyone else the also-rans competing against each other for second place.  Everyone else ended up being SNC and SpaceX and a rivalry was crafted via the forge of competition.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: TrevorMonty on 07/12/2021 10:41 am
SpaceX were favourite because they were already flying cargo Dragon. SNC missed out because NASA didn't think they had LAS engines sorted.
Hindsight is wonderful thing but looks like they would've beat Boeing to ISS

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Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: JAFO on 07/12/2021 01:25 pm
Why do you say SNC has grudge against SpaceX?.

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My personal opinion is that back in the day anyone who mattered assumed Boeing was the safe choice that would definitely be operational years before anyone else.  This made everyone else the also-rans competing against each other for second place.  Everyone else ended up being SNC and SpaceX and a rivalry was crafted via the forge of competition.


IIRC, the betting was SpaceX and SNC as the winners, and that Boeing threw a fit when they were not picked and used Congre$$ional influence to have SNC snubbed. It was even rumored that the decision WAS SpaceX/SNC, and it was revised when Boeing was informed they lost.


Boeing’s track record post-McD merger has not exactly been the best.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Joseph Peterson on 07/12/2021 02:16 pm
Why do you say SNC has grudge against SpaceX?.

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My personal opinion is that back in the day anyone who mattered assumed Boeing was the safe choice that would definitely be operational years before anyone else.  This made everyone else the also-rans competing against each other for second place.  Everyone else ended up being SNC and SpaceX and a rivalry was crafted via the forge of competition.


IIRC, the betting was SpaceX and SNC as the winners, and that Boeing threw a fit when they were not picked and used Congre$$ional influence to have SNC snubbed. It was even rumored that the decision WAS SpaceX/SNC, and it was revised when Boeing was informed they lost.


Boeing’s track record post-McD merger has not exactly been the best.

I don't remember SpaceX/SNC being winners.  Instead I remember a metric shed tonne of talk about how Boeing was the safe option and anyone else wouldn't be available to provide crew transportation to ISS until years later.

Granted back then I made the mistake of underestimating how accurate and precise NSF forums were and gave more credence to less reliable sources.  If anyone has a link to a good NSF forum topic post I should start my reeducation with I dearly hope you respond.  I'll check back within a day.  Thank you in advance for the links I am prepared to receive.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: JAFO on 07/13/2021 04:25 am
Granted back then I made the mistake of underestimating how accurate and precise NSF forums were and gave more credence to less reliable sources.  If anyone has a link to a good NSF forum topic post I should start my reeducation with I dearly hope you respond.  I'll check back within a day.  Thank you in advance for the links I am prepared to receive.
No worries. Here you go.

SNC protest article:  https://www.nasaspaceflight.com/2014/09/dream-chaser-fight-snc-protest-cctcap-decision/ (https://www.nasaspaceflight.com/2014/09/dream-chaser-fight-snc-protest-cctcap-decision/)


Various threads:
https://forum.nasaspaceflight.com/index.php?topic=35728.0 (https://forum.nasaspaceflight.com/index.php?topic=35728.0)
https://forum.nasaspaceflight.com/index.php?topic=29583.0 (https://forum.nasaspaceflight.com/index.php?topic=29583.0)

https://forum.nasaspaceflight.com/index.php?topic=28699.0 (https://forum.nasaspaceflight.com/index.php?topic=28699.0)
https://forum.nasaspaceflight.com/index.php?topic=34873.0 (https://forum.nasaspaceflight.com/index.php?topic=34873.0)

You can also look at the first post of this thread for a whole slew of articles dating back several years that cover all aspects of DC, or search for "ccdev dream chaser". Happy reading!!


(Man, tha brought back memories of the days before SLS when we hoped the next spacecraft would be Direct and crewed Dream Chaser.)
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Jim on 07/13/2021 11:49 am

Hindsight is wonderful thing but looks like they would've beat Boeing to ISS


No, they have their own problems with just the cargo version.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Jim on 07/13/2021 11:52 am
Which brings us back to: does Sierra stick with a more expensive launcher, and trust DC's capabilities to carry her through, or switch to a less expensive launcher to increase DC's chances of winning contracts, even if it gives work to a company Sierra apparently disfavours?


NASA isn't going to contract spacecraft that use the same launch vehicle.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: ncb1397 on 07/13/2021 04:49 pm
SpaceX were favourite because they were already flying cargo Dragon. SNC missed out because NASA didn't think they had LAS engines sorted.
Hindsight is wonderful thing but looks like they would've beat Boeing to ISS

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Dream Chaser was contracted only 16 months after Starliner was. So, assuming the OFT flight late July, that gives Dream Chaser until November 2022 to do an ISS flight on the same or better time table. Based on the below tweet from a month ago showing the state of the Dream Chaser, I would say we can't assume they will meet that time table...

www.twitter.com/SierraNevCorp/status/1402281018426597377

Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: JAFO on 07/13/2021 04:57 pm
SpaceX were favourite because they were already flying cargo Dragon. SNC missed out because NASA didn't think they had LAS engines sorted.
Hindsight is wonderful thing but looks like they would've beat Boeing to ISS

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Dream Chaser was contracted only 16 months after Starliner was. So, assuming the OFT flight late July, that gives Dream Chaser until November 2022 to do an ISS flight on the same or better time table. Based on the below tweet from a month ago showing the state of the Dream Chaser, I would say we can't assume they will meet that time table...

www.twitter.com/SierraNevCorp/status/1402281018426597377 (http://www.twitter.com/SierraNevCorp/status/1402281018426597377)


Those 16 months are important though, Starliner was pretty much ready to fly pre-Covid whereas Sierra Nevada had to disrupt Dreamchaser assembly because of Covid. It seems to me now the long pole is the booster, but it’s hard to tell since SNC is not being very gregarious with construction photos.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Joseph Peterson on 07/16/2021 02:24 am
Granted back then I made the mistake of underestimating how accurate and precise NSF forums were and gave more credence to less reliable sources.  If anyone has a link to a good NSF forum topic post I should start my reeducation with I dearly hope you respond.  I'll check back within a day.  Thank you in advance for the links I am prepared to receive.
No worries. Here you go.

SNC protest article:  https://www.nasaspaceflight.com/2014/09/dream-chaser-fight-snc-protest-cctcap-decision/ (https://www.nasaspaceflight.com/2014/09/dream-chaser-fight-snc-protest-cctcap-decision/)


Various threads:
https://forum.nasaspaceflight.com/index.php?topic=35728.0 (https://forum.nasaspaceflight.com/index.php?topic=35728.0)
https://forum.nasaspaceflight.com/index.php?topic=29583.0 (https://forum.nasaspaceflight.com/index.php?topic=29583.0)

https://forum.nasaspaceflight.com/index.php?topic=28699.0 (https://forum.nasaspaceflight.com/index.php?topic=28699.0)
https://forum.nasaspaceflight.com/index.php?topic=34873.0 (https://forum.nasaspaceflight.com/index.php?topic=34873.0)

You can also look at the first post of this thread for a whole slew of articles dating back several years that cover all aspects of DC, or search for "ccdev dream chaser". Happy reading!!


(Man, tha brought back memories of the days before SLS when we hoped the next spacecraft would be Direct and crewed Dream Chaser.)

Thank you for the links.  Three and a half days later I see there was a lot of popular support for Dream Chaser here.  I see rumors of untoward actions being the reason for Boeing's win.

That wasn't the only thing I saw.  The strangest thing was the occasional suggestion that Liberty might make a comeback.  What was unexpected was the frequency of claims that only one commercial crew provider would be selected.  As I expected there was plenty of talk of how Boeing was the safe option because of their history and "politics."  Then there was official documentation.  The most memorable was the thermometers that should CCiCAP milestone progress in a manner that made it appear that Boeing was way ahead.  This suggests to me that my memory that Boeing was viewed as the safe choice isn't completely flawed.

Now that I know when to look I'll dig into L2 and see what goodies I can find. 
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: yg1968 on 07/16/2021 11:12 pm
Granted back then I made the mistake of underestimating how accurate and precise NSF forums were and gave more credence to less reliable sources.  If anyone has a link to a good NSF forum topic post I should start my reeducation with I dearly hope you respond.  I'll check back within a day.  Thank you in advance for the links I am prepared to receive.
No worries. Here you go.

SNC protest article:  https://www.nasaspaceflight.com/2014/09/dream-chaser-fight-snc-protest-cctcap-decision/ (https://www.nasaspaceflight.com/2014/09/dream-chaser-fight-snc-protest-cctcap-decision/)


Various threads:
https://forum.nasaspaceflight.com/index.php?topic=35728.0 (https://forum.nasaspaceflight.com/index.php?topic=35728.0)
https://forum.nasaspaceflight.com/index.php?topic=29583.0 (https://forum.nasaspaceflight.com/index.php?topic=29583.0)

https://forum.nasaspaceflight.com/index.php?topic=28699.0 (https://forum.nasaspaceflight.com/index.php?topic=28699.0)
https://forum.nasaspaceflight.com/index.php?topic=34873.0 (https://forum.nasaspaceflight.com/index.php?topic=34873.0)

You can also look at the first post of this thread for a whole slew of articles dating back several years that cover all aspects of DC, or search for "ccdev dream chaser". Happy reading!!


(Man, tha brought back memories of the days before SLS when we hoped the next spacecraft would be Direct and crewed Dream Chaser.)

Thank you for the links.  Three and a half days later I see there was a lot of popular support for Dream Chaser here.  I see rumors of untoward actions being the reason for Boeing's win.

That wasn't the only thing I saw.  The strangest thing was the occasional suggestion that Liberty might make a comeback.  What was unexpected was the frequency of claims that only one commercial crew provider would be selected.  As I expected there was plenty of talk of how Boeing was the safe option because of their history and "politics."  Then there was official documentation.  The most memorable was the thermometers that should CCiCAP milestone progress in a manner that made it appear that Boeing was way ahead.  This suggests to me that my memory that Boeing was viewed as the safe choice isn't completely flawed.

Now that I know when to look I'll dig into L2 and see what goodies I can find.

NASA did indeed consider selecting only one CCtCap provider and that provider would have been Boeing according to Lori Garver.

In terms of SNC winning CCtCap, I think that those rumors weren't true. It is possible that had NASA not had enough funding, they might have considered a cheaper option than Boeing but that is speculative since NASA managed to convince Congress to fully fund CCtCap. There was all kinds of rumors on NSF but Gerst was the selection officer and Garver confirmed that he was very-pro Boeing at the time.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Joseph Peterson on 07/17/2021 02:52 am
Update:

After having read a few hundred L2 posts from 2014 I fully understand why Dragon/DC was the assumed winning pair in August of that year.  This is L2 so I'm not getting into details but I will link the topic I found most useful for posterity's sake.

https://forum.nasaspaceflight.com/index.php?topic=29445.0



And now to add some opinion:

In hindsight it is obvious that the parachute problems SpaceX discovered needed to be discovered.  The knowledge gained not only improves Dragon and Starliner, but also benefits Orion and any other future parachute user as well.  In my opinion this discovery alone justifies what has been spent of commercial crew development.  Selecting Boeing instead might not have discovered the parachute problems.  Therefore I am happy SpaceX was selected.

What is really bugging me now is the question I can't yet answer with the benefit of hindsight, "Could DC have entered operational service in 2019 or sooner?"  DC relies on "wings" instead of parachutes and wouldn't have been delayed due to the parachute problem.  This means in theory the answer could be yes.  Sadly we'll never know because the "safe" option, Starliner, was selected instead.



JAFO,

Thank you for submitting the post that resulted in my intellectual journey toward greater understanding
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: JAFO on 07/20/2021 09:18 pm

What is really bugging me now is the question I can't yet answer with the benefit of hindsight, "Could DC have entered operational service in 2019 or sooner?"  DC relies on "wings" instead of parachutes and wouldn't have been delayed due to the parachute problem.  This means in theory the answer could be yes.  Sadly we'll never know because the "safe" option, Starliner, was selected instead.



JAFO,

Thank you for submitting the post that resulted in my intellectual journey toward greater understanding

You're welcome.

Now, consider this: a small lifting body shuttle coulda/shoulda been developed in the 1970s except for....


Quote from: Bill Anders
Anders went along with the consensus that the space program should be “brought back down to Earth” to focus on weather, communications and military satellites. The question was whether to go whole hog on a large shuttle or build a smaller craft to test the waters and judge NASA’s claim that a shuttle would slash the cost of space delivery tenfold.

Anders, still mulling both approaches, vividly recalls a call from H.R. “Bob” Haldeman, Nixon’s chief of staff, bluntly asking which option would provide more aerospace jobs in California. When he gave the obvious answer — the big shuttle — that was it. Click, decision made.

The shuttle program was launched, the jobs were secured and NASA embarked on what Anders calls a four-decade-long detour. The shuttle was a spectacular vehicle, with an equally spectacular price tag: It wound up increasing the cost of spaceflight tenfold. “That is a 100-fold error,” Anders says, with clear disgust.

https://www.seattletimes.com/pacific-nw-magazine/with-a-view-from-beyond-the-moon-an-astronaut-talks-religion-politics-and-possibilities/ (https://www.seattletimes.com/pacific-nw-magazine/with-a-view-from-beyond-the-moon-an-astronaut-talks-religion-politics-and-possibilities/)

I wonder what a 1970s era mini-shuttle based on the HL-10, X-24A/B, M2F1/2 research would have looked like, without the Soviet BOR influence.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: JAFO on 07/20/2021 09:31 pm
Joseph, your next project is to research SLS vs Direct Launch on this forum. THAT will keep you busy for a while!!!
https://en.wikipedia.org/wiki/DIRECT (https://en.wikipedia.org/wiki/DIRECT)


https://www.youtube.com/watch?v=Z8tm4L5RTq0 (https://www.youtube.com/watch?v=Z8tm4L5RTq0)

:cheers:
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: SoftwareDude on 07/21/2021 02:30 am
Has any thought been given to creating a recoverable second stage using Dream Chaser's technology?  It seems like CST-100 is the ideal lifeboat design, Dragon, is the best cargo/crew transportation.  I don't see where Dream Chaser fits in that way.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: docmordrid on 07/21/2021 07:56 am
Has any thought been given to creating a recoverable second stage using Dream Chaser's technology?  It seems like CST-100 is the ideal lifeboat design, Dragon, is the best cargo/crew transportation.  I don't see where Dream Chaser fits in that way.

Dream Chaser has a few unique attributes, mainly it has a low-G entry and can land on many airport  runways, which provides rapid access to delicate/urgent return cargo or an ill/injured astronaut. It also has the Shooting Star logistics module, which can free-fly experiments and DoD has expressed interest for use as a cislunar "Orbital Outpost".link... (https://spacenews.com/three-companies-studying-orbital-outpost-space-station-concepts-for-defense-department/)
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: SoftwareDude on 07/21/2021 06:04 pm
Has any thought been given to creating a recoverable second stage using Dream Chaser's technology?  It seems like CST-100 is the ideal lifeboat design, Dragon, is the best cargo/crew transportation.  I don't see where Dream Chaser fits in that way.

Dream Chaser has a few unique attributes, mainly it has a low-G entry and can land on many airport  runways, which provides rapid access to delicate/urgent return cargo or an ill/injured astronaut. It also has the Shooting Star logistics module, which can free-fly experiments and DoD has expressed interest for use as a cislunar "Orbital Outpost".link... (https://spacenews.com/three-companies-studying-orbital-outpost-space-station-concepts-for-defense-department/)
Seems like a "nice to have" at this point unless we think further evolution would create new kinds of use cases. I don't know what those would be.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Joseph Peterson on 07/21/2021 06:31 pm
Joseph, your next project is to research SLS vs Direct Launch on this forum. THAT will keep you busy for a while!!!
https://en.wikipedia.org/wiki/DIRECT (https://en.wikipedia.org/wiki/DIRECT)


https://www.youtube.com/watch?v=Z8tm4L5RTq0 (https://www.youtube.com/watch?v=Z8tm4L5RTq0)

:cheers:

Thanks, but I've already read about DIRECT.  It would be nice if we'd gotten DIRECT but politics.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Asteroza on 08/19/2021 10:54 pm
The UPDATE thread showed the CBM mechanism, and I noticed it has an oval hatch. Is there an interesting reason why it's oval, rather than circular or rounded corner square?
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Tomness on 08/20/2021 12:54 pm
The UPDATE thread showed the CBM mechanism, and I noticed it has an oval hatch. Is there an interesting reason why it's oval, rather than circular or rounded corner square?

It's all about the relastate. As we have seen with Dragon 1 to Dragon 2 door hinge. Design trade offs for the most mass you can pack in the module.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Tywin on 09/06/2021 11:28 pm
Can the Dream Chaser be launch by Atlas V if the Vulcan is late for 2022 launch?
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: russianhalo117 on 09/07/2021 12:22 am
Can the Dream Chaser be launch by Atlas V if the Vulcan is late for 2022 launch?
It was originally planned on AV. It is the back up option for the first flight. The point of no return is this year. Arianespace's A64 is the Vulcan alternate after the point of no return for Atlas as all have been sold.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: vt_hokie on 09/24/2021 02:42 pm
The latest assembly photos seem to show a vehicle that still has a ways to go.  Do we have any recent estimates on when the completed vehicle will roll out and be shipped for testing?  Will it be going straight to KSC or to another facility like NASA Glenn for thermal vac testing?
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: StraumliBlight on 10/11/2021 03:21 pm
Has the DC300 variant been mentioned previously?
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: TrevorMonty on 10/11/2021 03:50 pm
Has the DC300 variant been mentioned previously?
DC300 seems like larger X-37 competitor.

Sent from my SM-G570Y using Tapatalk

Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: yg1968 on 10/12/2021 01:01 pm
Has the DC300 variant been mentioned previously?

It seems that the DC300 would have cargo bay doors. See slide 11 of the presentation (attached):

The same slide mentions point to point for the DC100 (cargo DC).

Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: AlexP on 10/12/2021 01:12 pm
Has the DC300 variant been mentioned previously?
3 month cycle for re-flight - cautious with room to improve or does it really just take that long to ensure a spacecraft is ready to go again?

EDIT - should say this is in reference to slide 6 the PDF in the quoted post.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: dglow on 11/19/2021 04:23 pm
These are beginning to show up on doors around the SSPF.

I agree.

Beautiful. Would that this had been our second commercial crew vehicle.



edit: added referenced post from updates thread
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: MattMason on 11/19/2021 04:46 pm
Beautiful. Would that this had been our second commercial crew vehicle.

It still could be.
The application period for Commercial Crew 2 contracts is still open as of this post.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Fmedici on 11/19/2021 04:52 pm
Maybe it has already been answered but how likely is it for the first Dream Chaser docking to ISS to happen before the first Starliner docking to ISS?
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Lee Jay on 11/19/2021 04:56 pm
Maybe it has already been answered but how likely is it for the first Dream Chaser docking to ISS to happen before the first Starliner docking to ISS?

In this case, your crystal ball is probably about as good as anyone else's.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: abaddon on 11/19/2021 04:59 pm
Beautiful. Would that this had been our second commercial crew vehicle.
I disagree, because the only way it would have been our second commercial crew vehicle would be if it had been chosen over Crew Dragon, and that would have been an unmitigated disaster as a combination.  (Note that when Sierra complained about not securing a contract, they advocated they should have been chosen over SpaceX, not Boeing).

That all said, I'm excited about this cash infusion.  Sierra has been very slow to realize their cargo version of DreamChaser and while I'm sure that's for a variety of reasons, I'd have to think lack of funding must be part of that equation.  I'm hopeful this will allow them to successfully finish their cargo version of the spacecraft and leverage that for an eventual crewed version.  Starliner was unexciting back when it was the "safe" choice and has aged very poorly since, so if Sierra can step in with a better alternative, and actually have the financial means to bring it to reality, I'd be ecstatic.  Best of luck to them!
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: MattMason on 11/19/2021 05:02 pm
Maybe it has already been answered but how likely is it for the first Dream Chaser docking to ISS to happen before the first Starliner docking to ISS?

None.
While the Dream Chaser Cargo system is scheduled to fly by 2022 (provided that Vulcan is operational soon), the original crewed vehicle was essentially mothballed after the Commercial Crew bid was lost.

But especially in light of Sierra Space's work on Commercial Space Station and Commercial Crew 2 RFIs, the crewed DC could (and I'm speculating) be readied for a flight prototype within a minimum of 2 years. Starliner will fly long before any DC crew prototype--and that's because it will require some level of human-rating and other work that the cargo version won't require. But DC Cargo flights might help a lot in development just as original cargo Dragons did for Crew Dragons.

(My crystal ball is no less sparkly or magical than any others.)
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: yg1968 on 11/19/2021 05:13 pm
Beautiful. Would that this had been our second commercial crew vehicle.

It still could be.
The application period for Commercial Crew 2 contracts is still open as of this post.

For the time, CCSTS (commercial crew 2 as you call it) is only a RFI but it should become a RFP early next year. But you are right that the timing of this announcement isn't a coincidence. Sierra Space wants to show that it is serious in pursuing crewed Dream Chaser.

For more on CCSTS, see this link:
https://forum.nasaspaceflight.com/index.php?topic=55039.0
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: yg1968 on 11/19/2021 05:15 pm
Maybe it has already been answered but how likely is it for the first Dream Chaser docking to ISS to happen before the first Starliner docking to ISS?

None.
While the Dream Chaser Cargo system is scheduled to fly by 2022 (provided that Vulcan is operational soon), the original crewed vehicle was essentially mothballed after the Commercial Crew bid was lost.

But especially in light of Sierra Space's work on Commercial Space Station and Commercial Crew 2 RFIs, the crewed DC could (and I'm speculating) be readied for a flight prototype within a minimum of 2 years. Starliner will fly long before any DC crew prototype--and that's because it will require some level of human-rating and other work that the cargo version won't require. But DC Cargo flights might help a lot in development just as original cargo Dragons did for Crew Dragons.

(My crystal ball is no less sparkly or magical than any others.)

Sierra Space said that crewed DC would be ready in 2026 in a presentation (see the link below). The RFI for CCSTS requires it to be certified by 2027.

https://forum.nasaspaceflight.com/index.php?topic=46038.msg2303374#msg2303374
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Lee Jay on 11/19/2021 05:17 pm
Maybe it has already been answered but how likely is it for the first Dream Chaser docking to ISS to happen before the first Starliner docking to ISS?

None.
While the Dream Chaser Cargo system is scheduled to fly by 2022 (provided that Vulcan is operational soon), the original crewed vehicle was essentially mothballed after the Commercial Crew bid was lost.

He didn't ask about crewed Dream Chaser.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: yg1968 on 11/19/2021 05:22 pm
Maybe it has already been answered but how likely is it for the first Dream Chaser docking to ISS to happen before the first Starliner docking to ISS?

None.
While the Dream Chaser Cargo system is scheduled to fly by 2022 (provided that Vulcan is operational soon), the original crewed vehicle was essentially mothballed after the Commercial Crew bid was lost.

He didn't ask about crewed Dream Chaser.

Even cargo DC is unlikely.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Lee Jay on 11/19/2021 05:23 pm
Maybe it has already been answered but how likely is it for the first Dream Chaser docking to ISS to happen before the first Starliner docking to ISS?

None.
While the Dream Chaser Cargo system is scheduled to fly by 2022 (provided that Vulcan is operational soon), the original crewed vehicle was essentially mothballed after the Commercial Crew bid was lost.

He didn't ask about crewed Dream Chaser.

Even cargo DC is unlikely.

Starliner seems increasingly unlikely as well, so it's kind of slow vs slow right now.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: dglow on 11/19/2021 06:39 pm
Beautiful. Would that this had been our second commercial crew vehicle.
I disagree, because the only way it would have been our second commercial crew vehicle would be if it had been chosen over Crew Dragon, and that would have been an unmitigated disaster as a combination.  (Note that when Sierra complained about not securing a contract, they advocated they should have been chosen over SpaceX, not Boeing).

I'm not certain that would have been the case. Reflecting back on the Commercial Crew awards, unofficial reports and other discussion at that time indicated that something... odd may have taken place with the award to Boeing. I say this with full disclosure that this is one person's take, only. I am not asserting fact.

NSF, as it does, was following the imminent CC awards very closely. This was just the forum at the time, nothing like what we see today with the YouTube channel. Several contributors in the know indicated that Dream Chaser had been selected. And, from all accounts, SNC believed the same. Then we heard reports of many Boeing personnel (executives, lobbyists) making the rounds in Washington DC. This was in the week leading up to the announcement. Don't ask me to cite anything, because I cannot and won't. Again, just one person's recollection.

It is safe to say that when the announcement was made and Dream Chaser was left out that it came as a surprise to many members here. Of course we all know the significant price disparity between Starliner's bid and Dragon's. And, having seen the entire HLS selection drama play out this past year, one could extrapolate and construct some educated suspicions. Is it within the realm of reason to speculate that Boeing originally came in even higher with their bid, perhaps much more than SNC's, but subsequently managed to lower their price? Again this is tea leaf-reading.

But there is one notable artifact, and that is a particular press event that SNC held. As I recall this was the event announcing their collaboration with ULA for lifting Cargo DC to the ISS. Anyway, one of the execs for SNC spoke and made an oblique reference to the Crew competition with a "many don't know how close we came" or something very close to that effect. It was short but stood out, and gave the distinct impression of a larger story behind those words.

Know that I do not write this to cast aspersions on Boeing. Before anyone goes throwing shade, saying 'that's impossible' and calling it 'conspiracy' or whatever, I ask only that you reflect on recent history. Recall the circumstances of Boeing's own HLS bid, which led to the resignation of HEOMD's Associate Administrator. Things like this do happen and we have all borne witness to them.



edit:clarity
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Lee Jay on 11/19/2021 07:45 pm
Beautiful. Would that this had been our second commercial crew vehicle.
I disagree, because the only way it would have been our second commercial crew vehicle would be if it had been chosen over Crew Dragon, and that would have been an unmitigated disaster as a combination.  (Note that when Sierra complained about not securing a contract, they advocated they should have been chosen over SpaceX, not Boeing).

That is a distortion of the truth.  SNC had complaints about both SpaceX's and Boeing's offers, specifically that SpaceX's financial resources were not objectively taken into account and that Boeing's claim of certification by 2017 was given too much weight (yeah - how'd that claim work out).  SNC's offer was about half a billion less than Boeing's but they didn't claim certification in 2017.  So they probably lost the bid by telling the truth rather that doing what Boeing did, which was enter a bid that was, in retrospect, overly optimistic to say the least.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Jim on 11/19/2021 07:56 pm
Beautiful. Would that this had been our second commercial crew vehicle.
I disagree, because the only way it would have been our second commercial crew vehicle would be if it had been chosen over Crew Dragon, and that would have been an unmitigated disaster as a combination.  (Note that when Sierra complained about not securing a contract, they advocated they should have been chosen over SpaceX, not Boeing).

I'm not certain that would have been the case. Reflecting back on the Commercial Crew awards, unofficial reports and other discussion at that time indicated that something... odd may have taken place with the award to Boeing. I say this with full disclosure that this is one person's take, only. I am not asserting fact.

NSF, as it does, was following the imminent CC awards very closely. This was just the forum at the time, nothing like what we see today with the YouTube channel. Several contributors in the know indicated that Dream Chaser had been selected. And, from all accounts, SNC believed the same. Then we heard reports of many Boeing personnel (executives, lobbyists) making the rounds in Washington DC. This was in the week leading up to the announcement. Don't ask me to cite anything, because I cannot and won't. Again, just one person's recollection.

It is safe to say that when the announcement was made and Dream Chaser was left out that it came as a surprise to many members here. Of course we all know the significant price disparity between Starliner's bid and Dragon's. And, having seen the entire HLS selection drama play out this past year, one could extrapolate and construct some educated suspicions. Is it within the realm of reason to speculate that Boeing originally came in even higher with their bid, perhaps much more than SNC's, but subsequently managed to lower their price? Again this is tea leaf-reading.

But there is one notable artifact, and that is a particular press event that SNC held. As I recall this was the event announcing their collaboration with ULA for lifting Cargo DC to the ISS. Anyway, one of the execs for SNC spoke and made an oblique reference to the Crew competition with a "many don't know how close we came" or something very close to that effect. It was short but stood out, and gave the distinct impression of a larger story behind those words.

Know that I do not write this to cast aspersions on Boeing. Before anyone goes throwing shade, saying 'that's impossible' and calling it 'conspiracy' or whatever, I ask only that you reflect on recent history. Recall the circumstances of Boeing's own HLS bid, which led to the resignation of HEOMD's Associate Administrator. Things like this do happen and we have all borne witness to them.


No and no


And they are not even close to getting CRS ready at this point (which means their CCP proposal was less credible).
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: dglow on 11/19/2021 08:10 pm
Beautiful. Would that this had been our second commercial crew vehicle.
I disagree, because the only way it would have been our second commercial crew vehicle would be if it had been chosen over Crew Dragon, and that would have been an unmitigated disaster as a combination.  (Note that when Sierra complained about not securing a contract, they advocated they should have been chosen over SpaceX, not Boeing).

I'm not certain that would have been the case. Reflecting back on the Commercial Crew awards, unofficial reports and other discussion at that time indicated that something... odd may have taken place with the award to Boeing. I say this with full disclosure that this is one person's take, only. I am not asserting fact.

NSF, as it does, was following the imminent CC awards very closely. This was just the forum at the time, nothing like what we see today with the YouTube channel. Several contributors in the know indicated that Dream Chaser had been selected. And, from all accounts, SNC believed the same. Then we heard reports of many Boeing personnel (executives, lobbyists) making the rounds in Washington DC. This was in the week leading up to the announcement. Don't ask me to cite anything, because I cannot and won't. Again, just one person's recollection.

It is safe to say that when the announcement was made and Dream Chaser was left out that it came as a surprise to many members here. Of course we all know the significant price disparity between Starliner's bid and Dragon's. And, having seen the entire HLS selection drama play out this past year, one could extrapolate and construct some educated suspicions. Is it within the realm of reason to speculate that Boeing originally came in even higher with their bid, perhaps much more than SNC's, but subsequently managed to lower their price? Again this is tea leaf-reading.

But there is one notable artifact, and that is a particular press event that SNC held. As I recall this was the event announcing their collaboration with ULA for lifting Cargo DC to the ISS. Anyway, one of the execs for SNC spoke and made an oblique reference to the Crew competition with a "many don't know how close we came" or something very close to that effect. It was short but stood out, and gave the distinct impression of a larger story behind those words.

Know that I do not write this to cast aspersions on Boeing. Before anyone goes throwing shade, saying 'that's impossible' and calling it 'conspiracy' or whatever, I ask only that you reflect on recent history. Recall the circumstances of Boeing's own HLS bid, which led to the resignation of HEOMD's Associate Administrator. Things like this do happen and we have all borne witness to them.


No and no


Great, would love to know more. No to which parts, Jim?
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: adrianwyard on 11/19/2021 08:27 pm
As I recall NASA reviewers of SNC's commercial crew proposal did not have confidence in their plan for powered abort (back then it was with hybrid motors). That alone could have forced them into third place.

Early/pad abort remains a question mark for their current designs for a crewed vehicle. On the other hand, Dream Chaser could well prove to be 'the best ride home' (for crew too).
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: yg1968 on 11/19/2021 09:33 pm
Beautiful. Would that this had been our second commercial crew vehicle.
I disagree, because the only way it would have been our second commercial crew vehicle would be if it had been chosen over Crew Dragon, and that would have been an unmitigated disaster as a combination.  (Note that when Sierra complained about not securing a contract, they advocated they should have been chosen over SpaceX, not Boeing).

I'm not certain that would have been the case. Reflecting back on the Commercial Crew awards, unofficial reports and other discussion at that time indicated that something... odd may have taken place with the award to Boeing. I say this with full disclosure that this is one person's take, only. I am not asserting fact.

NSF, as it does, was following the imminent CC awards very closely. This was just the forum at the time, nothing like what we see today with the YouTube channel. Several contributors in the know indicated that Dream Chaser had been selected. And, from all accounts, SNC believed the same. Then we heard reports of many Boeing personnel (executives, lobbyists) making the rounds in Washington DC. This was in the week leading up to the announcement. Don't ask me to cite anything, because I cannot and won't. Again, just one person's recollection.

It is safe to say that when the announcement was made and Dream Chaser was left out that it came as a surprise to many members here. Of course we all know the significant price disparity between Starliner's bid and Dragon's. And, having seen the entire HLS selection drama play out this past year, one could extrapolate and construct some educated suspicions. Is it within the realm of reason to speculate that Boeing originally came in even higher with their bid, perhaps much more than SNC's, but subsequently managed to lower their price? Again this is tea leaf-reading.

But there is one notable artifact, and that is a particular press event that SNC held. As I recall this was the event announcing their collaboration with ULA for lifting Cargo DC to the ISS. Anyway, one of the execs for SNC spoke and made an oblique reference to the Crew competition with a "many don't know how close we came" or something very close to that effect. It was short but stood out, and gave the distinct impression of a larger story behind those words.

Know that I do not write this to cast aspersions on Boeing. Before anyone goes throwing shade, saying 'that's impossible' and calling it 'conspiracy' or whatever, I ask only that you reflect on recent history. Recall the circumstances of Boeing's own HLS bid, which led to the resignation of HEOMD's Associate Administrator. Things like this do happen and we have all borne witness to them.


No and no


Great, would love to know more. No to which parts, Jim?

No to everything. The awards for commercial crew don't usually leak until they are announced to the companies. The rumors that Dream Chaser had won an award for CCtCap were just that, rumors (and I remember reading the same rumors as you did but they were proven to be false).

Furthermore, had any of this been true, it would have been protested by SNC. Here is a copy of the GAO decision and it is clear from that decision that SNC was protesting the award given to SpaceX, not Boeing.

https://www.gao.gov/assets/b-410485,b-410485.2,b-410485.3.pdf
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: dglow on 11/19/2021 10:17 pm
No and no

Great, would love to know more. No to which parts, Jim?

No to everything. The awards for commercial crew don't usually leak until they are announced to the companies. The rumors that Dream Chaser had won an award for CCtCap were just that, rumors (and I remember reading the same rumors as you did but they were proven to be false).

Furthermore, had any of this been true, it would have been protested by SNC. Here is a copy of the GAO decision and it is clear from that decision that SNC was protesting the award given to SpaceX, not Boeing.

https://www.gao.gov/assets/b-410485,b-410485.2,b-410485.3.pdf

Thanks. I have read the GAO's decision, as well as Gerstenmaier's selection statement. I'm glad you recall the rumors and speculation; do you similarly recollect the reports of Boeing personnel?

I openly admit, and call out, that which is speculation on my part. It does stand that what once seemed far-fetched has, now, been revealed as demonstrated by the same company, though of course with a different procurement.

Also, thank you for explaining yourself with more than two words. Respect.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: yg1968 on 11/20/2021 12:28 am
No and no

Great, would love to know more. No to which parts, Jim?

No to everything. The awards for commercial crew don't usually leak until they are announced to the companies. The rumors that Dream Chaser had won an award for CCtCap were just that, rumors (and I remember reading the same rumors as you did but they were proven to be false).

Furthermore, had any of this been true, it would have been protested by SNC. Here is a copy of the GAO decision and it is clear from that decision that SNC was protesting the award given to SpaceX, not Boeing.

https://www.gao.gov/assets/b-410485,b-410485.2,b-410485.3.pdf

Thanks. I have read the GAO's decision, as well as Gerstenmaier's selection statement. I'm glad you recall the rumors and speculation; do you similarly recollect the reports of Boeing personnel?

I openly admit, and call out, that which is speculation on my part. It does stand that what once seemed far-fetched has, now, been revealed as demonstrated by the same company, though of course with a different procurement.

Also, thank you for explaining yourself with more than two words. Respect.

I don't remember the rumors from Boeing personnel. A lot of Boeing personnel thought that they would be the only ones selected. But at the same, I remember that there was issues as to whether there would be sufficient funding for CCtCap and whether NASA could afford two providers, especially if one of them was Boeing.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: JAFO on 11/20/2021 01:25 am
These are beginning to show up on doors around the SSPF.I agree.
Want.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: TomH on 11/20/2021 03:51 am
WaPo article today:
https://www.washingtonpost.com/technology/2021/11/19/sierra-space-investment-dream-chaser-orbital-reef/
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: dglow on 11/20/2021 07:30 am
I don't remember the rumors from Boeing personnel. A lot of Boeing personnel thought that they would be the only ones selected. But at the same, I remember that there was issues as to whether there would be sufficient funding for CCtCap and whether NASA could afford two providers, especially if one of them was Boeing.

The question at the time was whether or not NASA would select three providers.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: TrevorMonty on 11/20/2021 09:09 pm
They will go public eventually, maybe before crew version flies. If RL is anything to go by, investors will end up with large windfall and the publicly traded company a warchest  for more expansion.

Sent from my SM-T733 using Tapatalk

Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: yg1968 on 11/22/2021 04:33 pm
I don't remember the rumors from Boeing personnel. A lot of Boeing personnel thought that they would be the only ones selected. But at the same, I remember that there was issues as to whether there would be sufficient funding for CCtCap and whether NASA could afford two providers, especially if one of them was Boeing.

The question at the time was whether or not NASA would select three providers.

Three providers was never considered for CCtCap. A number of Boeing employees on this forum felt that only one would be chosen. Lori Garver said that Gerst was considering selecting just one provider and that one was Boeing.

For CRS2, there was a debate as to whether there should be 2 or 3. I favored 3 providers and fortunately was right.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: abaddon on 11/22/2021 07:11 pm
I don't remember the rumors from Boeing personnel. A lot of Boeing personnel thought that they would be the only ones selected. But at the same, I remember that there was issues as to whether there would be sufficient funding for CCtCap and whether NASA could afford two providers, especially if one of them was Boeing.

The question at the time was whether or not NASA would select three providers.

Three providers was never considered for CCtCap. A number of Boeing employees on this forum felt that only one would be chosen. Lori Garver said that Gerst was considering selecting just one provider and that one was Boeing.

For CRS2, there was a debate as to whether there should be 2 or 3. I favored 3 providers and fortunately was right.
More specifically, Garver said that Gerst had to be talked out of sole-selecting Boeing.  I can only imagine where we would (or more accurately wouldn't) be now if that mistake had been made.

In any case, on topic of Sierra Space, hoping to hear more about the cargo vessel with this funding source secured and some credible launch dates.  Obviously it's tied up with Vulcan so we need both for it to move forward.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Lee Jay on 11/22/2021 07:32 pm
In any case, on topic of Sierra Space, hoping to hear more about the cargo vessel with this funding source secured and some credible launch dates.  Obviously it's tied up with Vulcan so we need both for it to move forward.

DC is tied up with Vulcan and Vulcan is tied up with Blue Origin.  Kind of scary, actually.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: TrevorMonty on 11/23/2021 12:14 am
Cargo DC can use other LVs eg A6, F9 if fairing is big enough. Crew is different and tends to be locked to LV.

Sent from my SM-G570Y using Tapatalk

Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: deadman1204 on 01/31/2022 08:50 pm
Cargo DC can use other LVs eg A6, F9 if fairing is big enough. Crew is different and tends to be locked to LV.

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Can it really though? Starliner is "technically" able to use a falcon 9, but that'd actually take a ton of time and stuff to happen.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: whitelancer64 on 01/31/2022 09:46 pm
Cargo DC can use other LVs eg A6, F9 if fairing is big enough. Crew is different and tends to be locked to LV.

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Can it really though? Starliner is "technically" able to use a falcon 9, but that'd actually take a ton of time and stuff to happen.

The CST-100 was originally "launcher agnostic" but that hasn't been true since the Atlas V launch vehicle was selected in 2011. A whole host of modifications has been made to the vehicle that are Atlas V specific, most visibly the aerodynamic skirts added to the service module and the top of the Centaur.

However: the Cargo DreamChaser launches within a fairing, so it's far more flexible.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Jim on 01/31/2022 10:06 pm

The CST-100 was originally "launcher agnostic" but that hasn't been true since the Atlas V launch vehicle was selected in 2011. A whole host of modifications has been made to the vehicle that are Atlas V specific, most visibly the aerodynamic skirts added to the service module and the top of the Centaur.


Still is true.   The Centaur skirt is part of the Atlas and doesn't apply to other vehicles.  I believe the service module skirt was for aborts and would fly on other launch vehicles.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: whitelancer64 on 01/31/2022 10:29 pm

The CST-100 was originally "launcher agnostic" but that hasn't been true since the Atlas V launch vehicle was selected in 2011. A whole host of modifications has been made to the vehicle that are Atlas V specific, most visibly the aerodynamic skirts added to the service module and the top of the Centaur.


Still is true.   The Centaur skirt is part of the Atlas and doesn't apply to other vehicles.  I believe the service module skirt was for aborts and would fly on other launch vehicles.

And of course there are many other, much less visible things, like the umbilical connections from the Starliner to the Atlas V, software interfaces that let the vehicle "talk" to Atlas, and so on, that would need to be adapted or modified before Starliner could fly on another rocket.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Coastal Ron on 01/31/2022 11:12 pm
And of course there are many other, much less visible things, like the umbilical connections from the Starliner to the Atlas V, software interfaces that let the vehicle "talk" to Atlas, and so on, that would need to be adapted or modified before Starliner could fly on another rocket.

Sure, the many types of connections between two vehicles manufactured by two different companies may need some interfaces and special connections (+ time & money to get that done), but I don't think it is a matter of "if", just a matter of choice.

For instance, according to Wikipedia (https://en.wikipedia.org/wiki/Dream_Chaser#CRS-2_cargo_version):
Quote
To meet CRS-2 guidelines, the cargo Dream Chaser will have folding wings and fit within a 5 m diameter payload fairing, in contrast to the Crewed Dream Chaser, which is intended to launch without a fairing. The ability to fit into a payload fairing allows the cargo version to launch on any sufficiently capable vehicle, such as Ariane 5 as well as Atlas V.

That means it could fit in the Falcon 9/H payload volume (not sure if it needs the extended fairing though).

So I don't know about CST-100/Starliner, but Dream Chaser appears to be planning to launch on multiple launchers - either Atlas V or Vulcan with Centaur for ISS cargo, or Ariane 5/6.

I would guess that liquid connections to the Dream Chaser vehicle would be the most costly to implement on new launch vehicles, but I wouldn't imagine electrical connections would be that difficult since Sierra Space has been planning to launch Dream Chaser on a variety of launch vehicles, so they would have tried to make it as painless as possible to adapt to new ones.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: yg1968 on 02/01/2022 02:20 am
So I don't know about CST-100/Starliner, but Dream Chaser appears to be planning to launch on multiple launchers - either Atlas V or Vulcan with Centaur for ISS cargo, or Ariane 5/6.

Dream Chaser is launching on Vulcan and not Atlas V for CRS2. There are no concrete plans for other launchers as far as I know.

https://en.wikipedia.org/wiki/Dream_Chaser
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Lee Jay on 02/01/2022 02:48 am
So I don't know about CST-100/Starliner, but Dream Chaser appears to be planning to launch on multiple launchers - either Atlas V or Vulcan with Centaur for ISS cargo, or Ariane 5/6.

Dream Chaser is launching on Vulcan and not Atlas V for CRS2. There are no concrete plans for other launchers as far as I know.

https://en.wikipedia.org/wiki/Dream_Chaser

That's correct, but they always make a point to say that they are launcher agnostic.

25 minutes in.

https://www.youtube.com/watch?v=JfM2VLvN9Ow

Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: DanClemmensen on 02/01/2022 03:12 am

That means it could fit in the Falcon 9/H payload volume (not sure if it needs the extended fairing though).

So I don't know about CST-100/Starliner, but Dream Chaser appears to be planning to launch on multiple launchers - either Atlas V or Vulcan with Centaur for ISS cargo, or Ariane 5/6.

ULA is no longer taking new contracts for Atlas V launches. They will honor their existing contracts and then retire the rocket. 25 launches remain.
https://www.theverge.com/2021/8/26/22641048/ula-boeing-lockheed-end-sales-atlas-v-rocket-russia-rd180
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: russianhalo117 on 02/01/2022 04:26 am
So I don't know about CST-100/Starliner, but Dream Chaser appears to be planning to launch on multiple launchers - either Atlas V or Vulcan with Centaur for ISS cargo, or Ariane 5/6.

Dream Chaser is launching on Vulcan and not Atlas V for CRS2. There are no concrete plans for other launchers as far as I know.

https://en.wikipedia.org/wiki/Dream_Chaser

That's correct, but they always make a point to say that they are launcher agnostic.

25 minutes in.

https://www.youtube.com/watch?v=JfM2VLvN9Ow


They are. Ariane-A64 is the present alternate launcher.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: dglow on 02/01/2022 09:58 am
They are. Ariane-A64 is the present alternate launcher.

Excellent news. Where was this announced or mentioned?
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: yg1968 on 02/01/2022 09:25 pm
They are. Ariane-A64 is the present alternate launcher.

Excellent news. Where was this announced or mentioned?

I found this February 2019 article that mentions it:

Quote from: Rob Coppinger
The Dream Chaser spaceplane could be launched on the Arian 6 rocket and used as an uncrewed orbital laboratory by the European Space Agency (ESA) in the 2020s. [...]

“We could enhance the capability of the Dream Chaser. It would include kits for the accommodation of the payloads, to enhance the power and cooling and communications system,” says Marco Berg, head of human spaceflight at OHB System, a German company leading the €350,000 study for ESA. Of that amount, €250,000 came from ESA and the other €100,000 – from OHB.

The mission concept set out so far by the ESA-funded study involves Ariane Group’s Ariane 64 rocket, the Ariane 6 with four boosters, launching the Dream Chaser and a cargo module attached to it from Kourou. The cargo module and spaceplane would operate in LEO for up to three weeks. The Dream Chaser would return to an as yet unspecified European runway. The cargo module could remain in space for continuing automatic experiments before it burns up in the atmosphere.
 

https://asgardia.space/en/news/ESA-Considers-Dream-Chaser-for-Uncrewed-Missions-in-2020
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Starshipdown on 02/18/2022 06:27 pm
Quote from: Jeff Foust
Janet Kavandi of Sierra Space says on a commercial LEO destinations panel that the first Dream Chaser launch on a ULA Vulcan is now scheduled for the 1st quarter of 2023, “about a year from now

https://twitter.com/jeff_foust/status/1494068275386499072

Any indication why? Is it delays with Vulcan, DC's, or both?
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Jim on 02/18/2022 06:46 pm
DC's.  Due to COVID and standard schedule optimism
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Starshipdown on 02/18/2022 08:24 pm
DC's.  Due to COVID and standard schedule optimism

Thanks for the appraisal. Is DC still on track for shipment to Ohio?
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: deadman1204 on 04/18/2022 02:29 pm
Those images of the SNC fusilage really strike home how small the ship will be. I never realized it was gonna be that small
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: TrevorMonty on 04/24/2022 01:30 am
Delays in Dragon's AX-1 mission returning due to weather at landing zone, highlights the advantages of runway landing.
I'm doubt AX-1 crew won't be complaining about extra space time.

Sent from my SM-G570Y using Tapatalk

Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: baldusi on 04/24/2022 10:22 pm
Delays in Dragon's AX-1 mission returning due to weather at landing zone, highlights the advantages of runway landing.
I'm doubt AX-1 crew won't be complaining about extra space time.

Sent from my SM-G570Y using Tapatalk

Starliner lands on the desert on baloon cushins. So does Soyuz and Shenzhou. You don't need wings (or lifting body) to avoid the weather problems.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Lee Jay on 04/24/2022 11:31 pm
Delays in Dragon's AX-1 mission returning due to weather at landing zone, highlights the advantages of runway landing.
I'm doubt AX-1 crew won't be complaining about extra space time.

Sent from my SM-G570Y using Tapatalk

Starliner lands on the desert on baloon cushins. So does Soyuz and Shenzhou. You don't need wings (or lifting body) to avoid the weather problems.

Wings give you cross range and cross range gives you the ability to land at almost any major airport in the world.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: ZachS09 on 04/25/2022 12:26 am
Delays in Dragon's AX-1 mission returning due to weather at landing zone, highlights the advantages of runway landing.
I'm doubt AX-1 crew won't be complaining about extra space time.

Sent from my SM-G570Y using Tapatalk

Starliner lands on the desert on baloon cushins. So does Soyuz and Shenzhou. You don't need wings (or lifting body) to avoid the weather problems.

Wings give you cross range and cross range gives you the ability to land at almost any major airport in the world.

True, but no matter what spacecraft is landing on land, there’s also high altitude and ground winds to take into consideration.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Welsh Dragon on 04/25/2022 08:52 am
Delays in Dragon's AX-1 mission returning due to weather at landing zone, highlights the advantages of runway landing.
I'm doubt AX-1 crew won't be complaining about extra space time.

Sent from my SM-G570Y using Tapatalk

Starliner lands on the desert on baloon cushins. So does Soyuz and Shenzhou. You don't need wings (or lifting body) to avoid the weather problems.

Wings give you cross range and cross range gives you the ability to land at almost any major airport in the world.
How likely is it though that you'll land at any given major airport for a bit of weather? Surely for any case other than a medical emergency that's not worth the logistical nightmare?
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: TrevorMonty on 04/25/2022 10:40 am
Delays in Dragon's AX-1 mission returning due to weather at landing zone, highlights the advantages of runway landing.
I'm doubt AX-1 crew won't be complaining about extra space time.

Sent from my SM-G570Y using Tapatalk

Starliner lands on the desert on baloon cushins. So does Soyuz and Shenzhou. You don't need wings (or lifting body) to avoid the weather problems.

Wings give you cross range and cross range gives you the ability to land at almost any major airport in the world.
How likely is it though that you'll land at any given major airport for a bit of weather? Surely for any case other than a medical emergency that's not worth the logistical nightmare?
Airports are really closed by days of bad weather, typically a few hours at most.



Sent from my SM-G570Y using Tapatalk

Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: TrevorMonty on 04/25/2022 10:45 am


Delays in Dragon's AX-1 mission returning due to weather at landing zone, highlights the advantages of runway landing.
I'm doubt AX-1 crew won't be complaining about extra space time.

Sent from my SM-G570Y using Tapatalk

Starliner lands on the desert on baloon cushins. So does Soyuz and Shenzhou. You don't need wings (or lifting body) to avoid the weather problems.

Wings give you cross range and cross range gives you the ability to land at almost any major airport in the world.
How likely is it though that you'll land at any given major airport for a bit of weather? Surely for any case other than a medical emergency that's not worth the logistical nightmare?



Delays in Dragon's AX-1 mission returning due to weather at landing zone, highlights the advantages of runway landing.
I'm doubt AX-1 crew won't be complaining about extra space time.

Sent from my SM-G570Y using Tapatalk

Starliner lands on the desert on baloon cushins. So does Soyuz and Shenzhou. You don't need wings (or lifting body) to avoid the weather problems.

Soyuz has had a couple close calls due to it uncontrolled landings, eg frozen lake Capsules under parachutes are still at mercy of wind.

Sent from my SM-G570Y using Tapatalk

Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Welsh Dragon on 04/25/2022 10:53 am
Delays in Dragon's AX-1 mission returning due to weather at landing zone, highlights the advantages of runway landing.
I'm doubt AX-1 crew won't be complaining about extra space time.

Sent from my SM-G570Y using Tapatalk

Starliner lands on the desert on baloon cushins. So does Soyuz and Shenzhou. You don't need wings (or lifting body) to avoid the weather problems.

Wings give you cross range and cross range gives you the ability to land at almost any major airport in the world.
How likely is it though that you'll land at any given major airport for a bit of weather? Surely for any case other than a medical emergency that's not worth the logistical nightmare?
Airports are really closed by days of bad weather, typically a few hours at most.
Just because it can land at an airport doesn't mean it flies like a passenger plane. I'm not a pilot, but I would very much doubt Dream Chaser can land under the same range of adverse weather conditions regular planes can. You know, given how it's an unpowered glider that falls like a brick compared to a regular plane.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Lee Jay on 04/25/2022 01:41 pm
Delays in Dragon's AX-1 mission returning due to weather at landing zone, highlights the advantages of runway landing.
I'm doubt AX-1 crew won't be complaining about extra space time.

Sent from my SM-G570Y using Tapatalk

Starliner lands on the desert on baloon cushins. So does Soyuz and Shenzhou. You don't need wings (or lifting body) to avoid the weather problems.

Wings give you cross range and cross range gives you the ability to land at almost any major airport in the world.
How likely is it though that you'll land at any given major airport for a bit of weather? Surely for any case other than a medical emergency that's not worth the logistical nightmare?
Airports are really closed by days of bad weather, typically a few hours at most.
Just because it can land at an airport doesn't mean it flies like a passenger plane. I'm not a pilot, but I would very much doubt Dream Chaser can land under the same range of adverse weather conditions regular planes can. You know, given how it's an unpowered glider that falls like a brick compared to a regular plane.

Generally, the determining factor for the winds a plane can land in is wing loading. The higher the wing loading the more wind you can land in. DC has extremely high wing loading owing to the fact that it's mostly a lifting body.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: dglow on 04/25/2022 01:53 pm
Delays in Dragon's AX-1 mission returning due to weather at landing zone, highlights the advantages of runway landing.
I'm doubt AX-1 crew won't be complaining about extra space time.

Sent from my SM-G570Y using Tapatalk

Starliner lands on the desert on baloon cushins. So does Soyuz and Shenzhou. You don't need wings (or lifting body) to avoid the weather problems.

Wings give you cross range and cross range gives you the ability to land at almost any major airport in the world.
How likely is it though that you'll land at any given major airport for a bit of weather? Surely for any case other than a medical emergency that's not worth the logistical nightmare?
Airports are really closed by days of bad weather, typically a few hours at most.
Just because it can land at an airport doesn't mean it flies like a passenger plane. I'm not a pilot, but I would very much doubt Dream Chaser can land under the same range of adverse weather conditions regular planes can. You know, given how it's an unpowered glider that falls like a brick compared to a regular plane.

Generally, the determining factor for the winds a plane can land in is wing loading. The higher the wing loading the more wind you can land in. DC has extremely high wing loading owing to the fact that it's mostly a lifting body.

Would Dream Chaser's TPS make it less amenable to adverse weather than your average aircraft?
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Lee Jay on 04/25/2022 03:54 pm
Would Dream Chaser's TPS make it less amenable to adverse weather than your average aircraft?

I doubt it, but I'm not sure of its flight control authority.  It's possible that the limit is there.  Given its small size and small vertical area, I doubt it though.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: dwheeler on 04/25/2022 05:03 pm
Delays in Dragon's AX-1 mission returning due to weather at landing zone, highlights the advantages of runway landing.
I'm doubt AX-1 crew won't be complaining about extra space time.

Sent from my SM-G570Y using Tapatalk

Starliner lands on the desert on baloon cushins. So does Soyuz and Shenzhou. You don't need wings (or lifting body) to avoid the weather problems.

Wings give you cross range and cross range gives you the ability to land at almost any major airport in the world.
How likely is it though that you'll land at any given major airport for a bit of weather? Surely for any case other than a medical emergency that's not worth the logistical nightmare?
Airports are really closed by days of bad weather, typically a few hours at most.
Just because it can land at an airport doesn't mean it flies like a passenger plane. I'm not a pilot, but I would very much doubt Dream Chaser can land under the same range of adverse weather conditions regular planes can. You know, given how it's an unpowered glider that falls like a brick compared to a regular plane.

Generally, the determining factor for the winds a plane can land in is wing loading. The higher the wing loading the more wind you can land in. DC has extremely high wing loading owing to the fact that it's mostly a lifting body.
"Adverse weather" for aircraft is typically dealing with lightning, low level visibility, icing, turbulence, etc. Unless you talking about low level winds over 35+ knots most airliners hardly care about the wind. I doubt they're designing Dream Chaser to be able to handle much of any of those factors.

But in general, Welsh Dragon's point about diverting Dream Chaser to any old airport unless it's an emergency sounds right. Our ATC structure in this country, (and most other countries), deals with separating traffic using very well known and codified techniques of horizontal and vertical separation. To have some unpowered aircraft that comes barreling down in a steep dive at Mach whatever would require in effect shutting down the airspace by re-routing all commercial traffic. I think that's the only way ATC could deal with it. Which it could do in an emergency. But I don't think just saying "our normal airport has bad weather and we just don't want to wait for conditions to improve" is a valid reason for the disruption.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Lee Jay on 04/25/2022 06:34 pm
"Adverse weather" for aircraft is typically dealing with lightning, low level visibility, icing, turbulence, etc. Unless you talking about low level winds over 35+ knots most airliners hardly care about the wind. I doubt they're designing Dream Chaser to be able to handle much of any of those factors.

But in general, Welsh Dragon's point about diverting Dream Chaser to any old airport unless it's an emergency sounds right. Our ATC structure in this country, (and most other countries), deals with separating traffic using very well known and codified techniques of horizontal and vertical separation. To have some unpowered aircraft that comes barreling down in a steep dive at Mach whatever would require in effect shutting down the airspace by re-routing all commercial traffic. I think that's the only way ATC could deal with it. Which it could do in an emergency. But I don't think just saying "our normal airport has bad weather and we just don't want to wait for conditions to improve" is a valid reason for the disruption.

I agree with all of that.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: JAFO on 04/26/2022 01:28 am
Delays in Dragon's AX-1 mission returning due to weather at landing zone, highlights the advantages of runway landing.
I'm doubt AX-1 crew won't be complaining about extra space time.

Sent from my SM-G570Y using Tapatalk

Starliner lands on the desert on baloon cushins. So does Soyuz and Shenzhou. You don't need wings (or lifting body) to avoid the weather problems.

Wings give you cross range and cross range gives you the ability to land at almost any major airport in the world.
How likely is it though that you'll land at any given major airport for a bit of weather? Surely for any case other than a medical emergency that's not worth the logistical nightmare?
Airports are really closed by days of bad weather, typically a few hours at most.
Just because it can land at an airport doesn't mean it flies like a passenger plane. I'm not a pilot, but I would very much doubt Dream Chaser can land under the same range of adverse weather conditions regular planes can. You know, given how it's an unpowered glider that falls like a brick compared to a regular plane.

Generally, the determining factor for the winds a plane can land in is wing loading. The higher the wing loading the more wind you can land in. DC has extremely high wing loading owing to the fact that it's mostly a lifting body.

Another factor is control authority. With a nose skid I'm assuming they've using differential braking, but I don't think differential braking would give as much control as a steerable nose wheel would, it would be interesting to hear how much crosswind DC could handle with her control configuration.

They're not going to be landing DC at Newark in a Noreas'ter with blowing snow and an icy runway (BTDT), she's not designed for that, not many aircraft are. But she is designed to land on a generic aviation runway with non-hazardous props on board in a controlled manner on short notice, with the ability to crossrange into an otherwise out of reach airport in the event of an unusual situation (station evacuation, medical emergency, etc.)


Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Steven Pietrobon on 04/26/2022 07:24 am
Starliner lands on the desert on balloon cushions. So does Soyuz and Shenzhou. You don't need wings (or lifting body) to avoid the weather problems.

Soyuz and Shenzhou land in the desert, but not using airbags. They use retrorockets to cushion the landing. For capsules, if there is bad weather in the landing zone you simply wait in orbit for either the weather to clear or to target another landing location. The Space Shuttle also did that and I would expect Dreamchaser to do the same.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: baldusi on 04/26/2022 04:11 pm
Starliner lands on the desert on balloon cushions. So does Soyuz and Shenzhou. You don't need wings (or lifting body) to avoid the weather problems.

Soyuz and Shenzhou land in the desert, but not using airbags. They use retrorockets to cushion the landing. For capsules, if there is bad weather in the landing zone you simply wait in orbit for either the weather to clear or to target another landing location. The Space Shuttle also did that and I would expect Dreamchaser to do the same.

Yes indeed, bad grammar on my part.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Rocket Science on 05/09/2022 07:09 pm
Same video in update, just posted here for discussion.
https://www.youtube.com/watch?v=E6nh7N9I-sg
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: vt_hokie on 05/09/2022 10:39 pm
Exciting to see her coming together!  I'm looking forward to seeing a proper lifting body reusable shuttle in orbit and attached to ISS after so many decades of similar efforts that never quite made it.  I'm also a little nervous that it relies on the second launch of a brand new launch vehicle going well, but fingers crossed!
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Rocket Science on 05/12/2022 05:38 pm
https://www.youtube.com/watch?v=nkgpSKPMOvU
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: adrianwyard on 06/14/2022 08:48 pm
https://spacenews.com/sierra-space-to-start-astronaut-training-program/

Now that Sierra Space is giving more indications crewed Dream Chaser will actually exist (flying to Orbital Reef in ~2026 according to the company) I hope we'll learn some more details, i.e. differences from the cargo version. Some initial questions:

+ Launches on Vulcan Centaur? Others?
+ Launches outside payload fairing with fixed wings?
+ Windows: None? Minimal? Or full cockpit as seen in old renders?
+ No pad abort capability? Or during first stage? If yes, what propulsion?
+ Always launches with Shooting Star module?
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: TrevorMonty on 06/14/2022 09:07 pm


https://spacenews.com/sierra-space-to-start-astronaut-training-program/

Now that Sierra Space is giving more indications crewed Dream Chaser will actually exist (flying to Orbital Reef in ~2026 according to the company) I hope we'll learn some more details, i.e. differences from the cargo version. Some initial questions:

+ Launches on Vulcan Centaur? Others?
+ Launches outside payload fairing with fixed wings?
+ Windows: None? Minimal? Or full cockpit as seen in old renders?
+ No pad abort capability? Or during first stage? If yes, what propulsion?
+ Always launches with Shooting Star module?


Vulcan most likely but with 2026 as launch date Neutron, NG, Terran R are all possibilities.

Always launches bare on top of LV to allow for abort.
Last I heard it could launch with Shooting Star, which would be left behind during abort. See Angry Astronauts recent videos of visit to Sierra.
Windows not essential but will be there for passengers. Otherwise it would be like going to space in coffin.
LAS is a must, will share same fuel system as for orbital thrusters, which is what Starliner and Dragon do. Using low toxic fuel, no PPE clothing needed when near landed vehicle.





Sent from my SM-A528B using Tapatalk

Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: yg1968 on 06/16/2022 12:10 am
https://spacenews.com/sierra-space-to-start-astronaut-training-program/

Now that Sierra Space is giving more indications crewed Dream Chaser will actually exist (flying to Orbital Reef in ~2026 according to the company) I hope we'll learn some more details, i.e. differences from the cargo version. Some initial questions:

1- Launches on Vulcan Centaur? Others?
2- Launches outside payload fairing with fixed wings?
3- Windows: None? Minimal? Or full cockpit as seen in old renders?
4- No pad abort capability? Or during first stage? If yes, what propulsion?
5- Always launches with Shooting Star module?

My (educated) guesses are:

1- Vulcan Centaur only. Given that Vulcan-Centaur is already used for cargo, it is easier to stay with Vulcan-Centaur.
2- Yes.
3- Some of the recent images showed windows on the side for crewed DC.
4- I suspect that crewed DC will revert to the Orbitec thrusters for abort.
5- No Shooting Star on crewed DC.

But it would be nice to get official confirmation or a new video.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Robert_the_Doll on 06/16/2022 12:54 am
Staying with Vulcan because the cargo version is flying on it oversimplifies the issue. The crewed version will no doubt have to fly without a payload fairing as was originally to be the case when it was to fly on Atlas V for Commercial Crew and to allow the Dream Chaser vehicle to escape using its abort motors.

The other issues remain concerning if the Shooting Star module will be retained for this new crewed Dream Chaser. Either way, without the fairing, the Vulcan/Dream Chaser stack will need to be rigorously certified with computational fluid dynamics and wind tunnel testing.

The abort system itself will also have to be developed and tested as I believe the original hybrid rocket motors were dropped in favor of another. And then there's the matter of whether Sierra Space can afford anything beyond a pad abort flight test.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Lee Jay on 06/16/2022 01:07 am
Either way, without the fairing, the Vulcan/Dream Chaser stack will need to be rigorously certified with computational fluid dynamics and wind tunnel testing.

That's true, but there's an interesting side note about this - the loads on DC during ascent are lower than the loads on the fairing during ascent.  That makes sense to me (it's smaller, by far) but I just wouldn't have thought of it myself until Steve Lindsey told me that.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: JayWee on 06/16/2022 01:55 am
That's true, but there's an interesting side note about this - the loads on DC during ascent are lower than the loads on the fairing during ascent.  That makes sense to me (it's smaller, by far) but I just wouldn't have thought of it myself until Steve Lindsey told me that.
I think it's the asymmetry which makes people inherently suspicious.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Robert_the_Doll on 06/16/2022 01:57 am
Either way, without the fairing, the Vulcan/Dream Chaser stack will need to be rigorously certified with computational fluid dynamics and wind tunnel testing.

That's true, but there's an interesting side note about this - the loads on DC during ascent are lower than the loads on the fairing during ascent.  That makes sense to me (it's smaller, by far) but I just wouldn't have thought of it myself until Steve Lindsey told me that.

I believe the real issue is that of the instability that the Dream Chaser's asymmetrical lifting body shape creates during launch. It considerably complicates vehicle control.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: edzieba on 06/16/2022 11:29 am
Whilst launching within the current stock Vulcan fairing is not an option due to the need for continuous abort capability without blackzones, launching in a fairing whilst retaining abort capability is not impossible (and even lets you put the high-thrust abort motors onto the fairing rather than integrated into the vehicle) as is done with Soyuz, Shenzou, Orion, etc. It depends on which problem SNC and ULA think is more tractable:
- Modelling and stabilising the stack with a bare lifting body on top (and ensuring control through abort without recontact) and adding abort motor capability to the vehicle. As far as I can recall, only ASSET and BOR-5 (the mini-Buran, not the mini-Spirals) have been launched bare atop a stack, all other lifting bodies have been faired (or side-mount with no abort capability)
- Designing and manufacturing a more conformal - but no longer asymmetric - fairing with integrated high-thrust abort motors
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Lee Jay on 06/16/2022 12:51 pm
That's true, but there's an interesting side note about this - the loads on DC during ascent are lower than the loads on the fairing during ascent.  That makes sense to me (it's smaller, by far) but I just wouldn't have thought of it myself until Steve Lindsey told me that.
I think it's the asymmetry which makes people inherently suspicious.

I think there's a lot less asymmetry than people think.  Remember, the "wings" are at 90 degree angles to each other.

They've always planned to launch in bare mode, and have done simulation and test to validate that approach.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: edzieba on 06/16/2022 01:21 pm
That's true, but there's an interesting side note about this - the loads on DC during ascent are lower than the loads on the fairing during ascent.  That makes sense to me (it's smaller, by far) but I just wouldn't have thought of it myself until Steve Lindsey told me that.
I think it's the asymmetry which makes people inherently suspicious.

I think there's a lot less asymmetry than people think.  Remember, the "wings" are at 90 degree angles to each other.

They've always planned to launch in bare mode, and have done simulation and test to validate that approach.
The wings aren't the problem: Dream Chaser is a lifting body, so will generate a lift force when pushed through the air. If you fix the vehicle at an angle of attack to minimise lift at one point in flight, it will not be minimised at other points in flight due to the rapid and dramatic changes in pressure and velocity during ascent (i.e. there is no fixed angle that will null lift throughout the entire flight). Barring a launch mount that is actively controlled and pitches the vehicle about atop the stack during flight (a headache nobody want to be anywhere near) you either need a fixed fairing to eliminate the lift, or manage the varying force applied to the top of the stack through closed-loop thrust vectoring and structural stiffening.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Cherokee43v6 on 06/16/2022 01:37 pm
That's true, but there's an interesting side note about this - the loads on DC during ascent are lower than the loads on the fairing during ascent.  That makes sense to me (it's smaller, by far) but I just wouldn't have thought of it myself until Steve Lindsey told me that.
I think it's the asymmetry which makes people inherently suspicious.

I think there's a lot less asymmetry than people think.  Remember, the "wings" are at 90 degree angles to each other.

They've always planned to launch in bare mode, and have done simulation and test to validate that approach.
The wings aren't the problem: Dream Chaser is a lifting body, so will generate a lift force when pushed through the air. If you fix the vehicle at an angle of attack to minimise lift at one point in flight, it will not be minimised at other points in flight due to the rapid and dramatic changes in pressure and velocity during ascent (i.e. there is no fixed angle that will null lift throughout the entire flight). Barring a launch mount that is actively controlled and pitches the vehicle about atop the stack during flight (a headache nobody want to be anywhere near) you either need a fixed fairing to eliminate the lift, or manage the varying force applied to the top of the stack through closed-loop thrust vectoring and structural stiffening.

Would it be possible to design a trajectory that mitigates, or even takes advantage of that lift aspect?

Maybe set the Dream Chaser to minimize lift through the early stage(s) of flight and then set either a high angle (top down) or a low angle (top up) trajectory through the later stages?

edit last sentence for clarity
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Lee Jay on 06/16/2022 01:56 pm
That's true, but there's an interesting side note about this - the loads on DC during ascent are lower than the loads on the fairing during ascent.  That makes sense to me (it's smaller, by far) but I just wouldn't have thought of it myself until Steve Lindsey told me that.
I think it's the asymmetry which makes people inherently suspicious.

I think there's a lot less asymmetry than people think.  Remember, the "wings" are at 90 degree angles to each other.

They've always planned to launch in bare mode, and have done simulation and test to validate that approach.
The wings aren't the problem: Dream Chaser is a lifting body, so will generate a lift force when pushed through the air. If you fix the vehicle at an angle of attack to minimise lift at one point in flight, it will not be minimised at other points in flight due to the rapid and dramatic changes in pressure and velocity during ascent (i.e. there is no fixed angle that will null lift throughout the entire flight). Barring a launch mount that is actively controlled and pitches the vehicle about atop the stack during flight (a headache nobody want to be anywhere near) you either need a fixed fairing to eliminate the lift, or manage the varying force applied to the top of the stack through closed-loop thrust vectoring and structural stiffening.

A fairing is a lifting body as well, just a much larger one.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: jimvela on 06/16/2022 02:22 pm
A fairing is a lifting body as well, just a much larger one.

Maybe I misunderstand how HL-20 and similar lifting bodies like Dream Chaser work, but don't most rocket fairings go out of their way to not have any asymmetric lift vectors? 
E.g. though there are inevitably interesting aerodynamics through ascent, fairings generally do not have a built-in lift vector in one axis- which is what makes the shape appealing for re-entry... and challenging for control on ascent.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Lee Jay on 06/16/2022 02:30 pm
A fairing is a lifting body as well, just a much larger one.

Maybe I misunderstand how HL-20 and similar lifting bodies like Dream Chaser work, but don't most rocket fairings go out of their way to not have any asymmetric lift vectors? 
E.g. though there are inevitably interesting aerodynamics through ascent, fairings generally do not have a built-in lift vector in one axis- which is what makes the shape appealing for re-entry... and challenging for control on ascent.

It still has lift.  It may be virtually identical in all directions (it's a cylinder with a cone on top) but it still has lift, and a whole lot of it.  The fact that the lift isn't perfectly symmetrical on DC isn't particularly important as that's the case with every single airplane ever made as well, and they're perfectly controllable.  The fact that DC's lift is far lower in magnitude than what comes from a fairing is more important.  The control authority of the thrust vectoring system is quite good, so I doubt seriously if that's a problem.  I suspect the loads imparted are a more important thing to analyze because the load path is different than the way a satellite is mounted unless you transmit those loads the same way the fairing does.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: yg1968 on 06/17/2022 01:02 pm
Staying with Vulcan because the cargo version is flying on it oversimplifies the issue.

These issues would exist on any LV. There is no reason to believe that they are worse on Vulcan.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: edzieba on 06/17/2022 01:17 pm
A fairing is a lifting body as well, just a much larger one.

Maybe I misunderstand how HL-20 and similar lifting bodies like Dream Chaser work, but don't most rocket fairings go out of their way to not have any asymmetric lift vectors? 
E.g. though there are inevitably interesting aerodynamics through ascent, fairings generally do not have a built-in lift vector in one axis- which is what makes the shape appealing for re-entry... and challenging for control on ascent.

It still has lift.  It may be virtually identical in all directions (it's a cylinder with a cone on top) but it still has lift, and a whole lot of it.  The fact that the lift isn't perfectly symmetrical on DC isn't particularly important as that's the case with every single airplane ever made as well, and they're perfectly controllable.  The fact that DC's lift is far lower in magnitude than what comes from a fairing is more important.  The control authority of the thrust vectoring system is quite good, so I doubt seriously if that's a problem.  I suspect the loads imparted are a more important thing to analyze because the load path is different than the way a satellite is mounted unless you transmit those loads the same way the fairing does.
The only tile the nose will have 'lift' is in a body lift condition where the entire vehicle is also generating lift due to off-axis thrust. With a normal gravity-turn trajectory the thrust axis is almost always aligned with the vehicle axis so 'lift' is close to zero, and any lift force there is is applied to the vehicle body as well as the nose. The difference with a lifting body is that there is no zero lit condition available throughout ascent: either the there is a force applied from the lifting body but not the stack (thrust aligned with vehicle axis), no force from the lifting body but force from the stack (thrust axis aligned with the lifting body's speed-and-altitude-dependant effective 0 AoA), or force applied by both (thrust axis aligned to balance both offsetting forces to prevent uncommanded steering). All result in a net shear force on the vehicle that is not present with an axisymmetric nose.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Lee Jay on 06/17/2022 01:29 pm
A fairing is a lifting body as well, just a much larger one.

Maybe I misunderstand how HL-20 and similar lifting bodies like Dream Chaser work, but don't most rocket fairings go out of their way to not have any asymmetric lift vectors? 
E.g. though there are inevitably interesting aerodynamics through ascent, fairings generally do not have a built-in lift vector in one axis- which is what makes the shape appealing for re-entry... and challenging for control on ascent.

It still has lift.  It may be virtually identical in all directions (it's a cylinder with a cone on top) but it still has lift, and a whole lot of it.  The fact that the lift isn't perfectly symmetrical on DC isn't particularly important as that's the case with every single airplane ever made as well, and they're perfectly controllable.  The fact that DC's lift is far lower in magnitude than what comes from a fairing is more important.  The control authority of the thrust vectoring system is quite good, so I doubt seriously if that's a problem.  I suspect the loads imparted are a more important thing to analyze because the load path is different than the way a satellite is mounted unless you transmit those loads the same way the fairing does.
The only tile the nose will have 'lift' is in a body lift condition where the entire vehicle is also generating lift due to off-axis thrust. With a normal gravity-turn trajectory the thrust axis is almost always aligned with the vehicle axis so 'lift' is close to zero, and any lift force there is is applied to the vehicle body as well as the nose. The difference with a lifting body is that there is no zero lit condition available throughout ascent: either the there is a force applied from the lifting body but not the stack (thrust aligned with vehicle axis), no force from the lifting body but force from the stack (thrust axis aligned with the lifting body's speed-and-altitude-dependant effective 0 AoA), or force applied by both (thrust axis aligned to balance both offsetting forces to prevent uncommanded steering). All result in a net shear force on the vehicle that is not present with an axisymmetric nose.

Why wouldn't there be a geometric angle at which DC could be mounted so that it's at a zero-lift condition when the rest of the rocket is at a zero lift condition?
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: greybeardengineer on 06/17/2022 07:05 pm
A fairing is a lifting body as well, just a much larger one.

Maybe I misunderstand how HL-20 and similar lifting bodies like Dream Chaser work, but don't most rocket fairings go out of their way to not have any asymmetric lift vectors? 
E.g. though there are inevitably interesting aerodynamics through ascent, fairings generally do not have a built-in lift vector in one axis- which is what makes the shape appealing for re-entry... and challenging for control on ascent.

It still has lift.  It may be virtually identical in all directions (it's a cylinder with a cone on top) but it still has lift, and a whole lot of it.  The fact that the lift isn't perfectly symmetrical on DC isn't particularly important as that's the case with every single airplane ever made as well, and they're perfectly controllable.  The fact that DC's lift is far lower in magnitude than what comes from a fairing is more important.  The control authority of the thrust vectoring system is quite good, so I doubt seriously if that's a problem.  I suspect the loads imparted are a more important thing to analyze because the load path is different than the way a satellite is mounted unless you transmit those loads the same way the fairing does.
The only tile the nose will have 'lift' is in a body lift condition where the entire vehicle is also generating lift due to off-axis thrust. With a normal gravity-turn trajectory the thrust axis is almost always aligned with the vehicle axis so 'lift' is close to zero, and any lift force there is is applied to the vehicle body as well as the nose. The difference with a lifting body is that there is no zero lit condition available throughout ascent: either the there is a force applied from the lifting body but not the stack (thrust aligned with vehicle axis), no force from the lifting body but force from the stack (thrust axis aligned with the lifting body's speed-and-altitude-dependant effective 0 AoA), or force applied by both (thrust axis aligned to balance both offsetting forces to prevent uncommanded steering). All result in a net shear force on the vehicle that is not present with an axisymmetric nose.

Why wouldn't there be a geometric angle at which DC could be mounted so that it's at a zero-lift condition when the rest of the rocket is at a zero lift condition?

The problem with a lifting body or winged spacecraft on the tip of a rocket instead of a PLF is the aerodynamic response to a small yaw error is quite different from the response of a small pitch error instead of being basically the same. It can be overcome with brute force (enhanced control authority and strengthening the rocket against buckling) but if it requires a custom version of the launcher then things get expensive fast. The regular Titan had no tail fins but the variant in development for launching the Dyna-Soar spaceplane before cancellation had huge tail fins that were asymmetric cruciform (the fins aligned with the Dyna-Soar's wings were much larger).
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Lee Jay on 06/17/2022 07:12 pm
A fairing is a lifting body as well, just a much larger one.

Maybe I misunderstand how HL-20 and similar lifting bodies like Dream Chaser work, but don't most rocket fairings go out of their way to not have any asymmetric lift vectors? 
E.g. though there are inevitably interesting aerodynamics through ascent, fairings generally do not have a built-in lift vector in one axis- which is what makes the shape appealing for re-entry... and challenging for control on ascent.

It still has lift.  It may be virtually identical in all directions (it's a cylinder with a cone on top) but it still has lift, and a whole lot of it.  The fact that the lift isn't perfectly symmetrical on DC isn't particularly important as that's the case with every single airplane ever made as well, and they're perfectly controllable.  The fact that DC's lift is far lower in magnitude than what comes from a fairing is more important.  The control authority of the thrust vectoring system is quite good, so I doubt seriously if that's a problem.  I suspect the loads imparted are a more important thing to analyze because the load path is different than the way a satellite is mounted unless you transmit those loads the same way the fairing does.
The only tile the nose will have 'lift' is in a body lift condition where the entire vehicle is also generating lift due to off-axis thrust. With a normal gravity-turn trajectory the thrust axis is almost always aligned with the vehicle axis so 'lift' is close to zero, and any lift force there is is applied to the vehicle body as well as the nose. The difference with a lifting body is that there is no zero lit condition available throughout ascent: either the there is a force applied from the lifting body but not the stack (thrust aligned with vehicle axis), no force from the lifting body but force from the stack (thrust axis aligned with the lifting body's speed-and-altitude-dependant effective 0 AoA), or force applied by both (thrust axis aligned to balance both offsetting forces to prevent uncommanded steering). All result in a net shear force on the vehicle that is not present with an axisymmetric nose.

Why wouldn't there be a geometric angle at which DC could be mounted so that it's at a zero-lift condition when the rest of the rocket is at a zero lift condition?

The problem with a lifting body or winged spacecraft on the tip of a rocket instead of a PLF is the aerodynamic response to a small yaw error is quite different from the response of a small pitch error instead of being basically the same. It can be overcome with brute force (enhanced control authority and strengthening the rocket against buckling) but if it requires a custom version of the launcher then things get expensive fast. The regular Titan had no tail fins but the variant in development for launching the Dyna-Soar spaceplane before cancellation had huge tail fins that were asymmetric cruciform (the fins aligned with the Dyna-Soar's wings were much larger).

I really think this is a non-issue.  The forces on a rocket are asymmetrical frequently, and of far higher magnitudes when flying through wind shear.  That the response to an angle of attack in one direction is very slightly different than in the other direction might require some tuning of the control laws (gains/poles/zeros), but it's a tiny craft compared to the PLF so the control authority is likely already there, in my opinion.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: greybeardengineer on 06/17/2022 07:37 pm
Why wouldn't there be a geometric angle at which DC could be mounted so that it's at a zero-lift condition when the rest of the rocket is at a zero lift condition?

The problem with a lifting body or winged spacecraft on the tip of a rocket instead of a PLF is the aerodynamic response to a small yaw error is quite different from the response of a small pitch error instead of being basically the same. It can be overcome with brute force (enhanced control authority and strengthening the rocket against buckling) but if it requires a custom version of the launcher then things get expensive fast. The regular Titan had no tail fins but the variant in development for launching the Dyna-Soar spaceplane before cancellation had huge tail fins that were asymmetric cruciform (the fins aligned with the Dyna-Soar's wings were much larger).

I really think this is a non-issue.  The forces on a rocket are asymmetrical frequently, and of far higher magnitudes when flying through wind shear.  That the response to an angle of attack in one direction is very slightly different than in the other direction might require some tuning of the control laws (gains/poles/zeros), but it's a tiny craft compared to the PLF so the control authority is likely already there, in my opinion.

Perhaps but the late stage aerodynamic add-ons to Starliner and its Centaur adaptor even for the rather benign and symmetrical OML of a capsule suggests it is not as trivial a matter as you seem to think. At the very least a comprehensive engineering study would be required for each different launcher under consideration, likely in cooperation with/outsourced to each provider.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Lee Jay on 06/17/2022 11:47 pm
Why wouldn't there be a geometric angle at which DC could be mounted so that it's at a zero-lift condition when the rest of the rocket is at a zero lift condition?

The problem with a lifting body or winged spacecraft on the tip of a rocket instead of a PLF is the aerodynamic response to a small yaw error is quite different from the response of a small pitch error instead of being basically the same. It can be overcome with brute force (enhanced control authority and strengthening the rocket against buckling) but if it requires a custom version of the launcher then things get expensive fast. The regular Titan had no tail fins but the variant in development for launching the Dyna-Soar spaceplane before cancellation had huge tail fins that were asymmetric cruciform (the fins aligned with the Dyna-Soar's wings were much larger).

I really think this is a non-issue.  The forces on a rocket are asymmetrical frequently, and of far higher magnitudes when flying through wind shear.  That the response to an angle of attack in one direction is very slightly different than in the other direction might require some tuning of the control laws (gains/poles/zeros), but it's a tiny craft compared to the PLF so the control authority is likely already there, in my opinion.

Perhaps but the late stage aerodynamic add-ons to Starliner and its Centaur adaptor even for the rather benign and symmetrical OML of a capsule suggests it is not as trivial a matter as you seem to think.

As I recall, those were for mach instabilities (shock wave control), not control authority.  Do I remember that wrong?

Quote
At the very least a comprehensive engineering study would be required for each different launcher under consideration, likely in cooperation with/outsourced to each provider.

Unquestionably.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: edzieba on 06/18/2022 08:03 am
A fairing is a lifting body as well, just a much larger one.

Maybe I misunderstand how HL-20 and similar lifting bodies like Dream Chaser work, but don't most rocket fairings go out of their way to not have any asymmetric lift vectors? 
E.g. though there are inevitably interesting aerodynamics through ascent, fairings generally do not have a built-in lift vector in one axis- which is what makes the shape appealing for re-entry... and challenging for control on ascent.

It still has lift.  It may be virtually identical in all directions (it's a cylinder with a cone on top) but it still has lift, and a whole lot of it.  The fact that the lift isn't perfectly symmetrical on DC isn't particularly important as that's the case with every single airplane ever made as well, and they're perfectly controllable.  The fact that DC's lift is far lower in magnitude than what comes from a fairing is more important.  The control authority of the thrust vectoring system is quite good, so I doubt seriously if that's a problem.  I suspect the loads imparted are a more important thing to analyze because the load path is different than the way a satellite is mounted unless you transmit those loads the same way the fairing does.
The only tile the nose will have 'lift' is in a body lift condition where the entire vehicle is also generating lift due to off-axis thrust. With a normal gravity-turn trajectory the thrust axis is almost always aligned with the vehicle axis so 'lift' is close to zero, and any lift force there is is applied to the vehicle body as well as the nose. The difference with a lifting body is that there is no zero lit condition available throughout ascent: either the there is a force applied from the lifting body but not the stack (thrust aligned with vehicle axis), no force from the lifting body but force from the stack (thrust axis aligned with the lifting body's speed-and-altitude-dependant effective 0 AoA), or force applied by both (thrust axis aligned to balance both offsetting forces to prevent uncommanded steering). All result in a net shear force on the vehicle that is not present with an axisymmetric nose.

Why wouldn't there be a geometric angle at which DC could be mounted so that it's at a zero-lift condition when the rest of the rocket is at a zero lift condition?
There is. The problem is, that angle is not fixed when you are varying atmospheric pressure and velocity over an extreme range in a very short period. You can pick a single AoA that works instantaneously for any chosen point in flight, but not one valid for the entire flight.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: TrevorMonty on 06/18/2022 07:57 pm
DC is quite capable counting any lift it creates with its own control surfaces.

Sent from my SM-A528B using Tapatalk

Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: John Santos on 06/18/2022 08:33 pm
DC is quite capable counting any lift it creates with its own control surfaces.

Sent from my SM-A528B using Tapatalk
I don't KNOW this is true, but it is possible and the Shuttle used its control surfaces during launch to mitigate lift and other aerodynamic forces.  I also don't know if it acitvely controlled those surfaces or just preset them to minimize the effects during launch.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: DaveS on 06/18/2022 08:42 pm
DC is quite capable counting any lift it creates with its own control surfaces.

Sent from my SM-A528B using Tapatalk
I don't KNOW this is true, but it is possible and the Shuttle used its control surfaces during launch to mitigate lift and other aerodynamic forces.  I also don't know if it acitvely controlled those surfaces or just preset them to minimize the effects during launch.
It was purely load relief using the elevons. The Rudder/Speedbrake and Body Flap remained in their launch positions. Once the critical loads point had been passed, the elevons returned to their normal 0° positions.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: edzieba on 06/20/2022 09:16 am
DC is quite capable counting any lift it creates with its own control surfaces.

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Which then gets you into the realm of tying payload systems tightly into launch vehicle control loops.
It's not a matter of unfaired launch being impossible, it's just a choice of which set of problems you choose to solve: launching unfaired and dealing with aerodynamics during ascent and abort profiles (and where to put abort motors), or launching faired and dealing with manufacturing a new item (fairing). Both are workable options, it's just a choice of which they choose to work on.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: TrevorMonty on 06/20/2022 10:32 am
DC is quite capable counting any lift it creates with its own control surfaces.

Sent from my SM-A528B using Tapatalk
Which then gets you into the realm of tying payload systems tightly into launch vehicle control loops.
It's not a matter of unfaired launch being impossible, it's just a choice of which set of problems you choose to solve: launching unfaired and dealing with aerodynamics during ascent and abort profiles (and where to put abort motors), or launching faired and dealing with manufacturing a new item (fairing). Both are workable options, it's just a choice of which they choose to work on.
Crew DC and LV need to be actively communicating so DC knows when to activate LAS due to LV failure.

In saying that DC doesn't need to talk to LV for control surfaces movements. Can be preset range of positions either based on time or altitude. Doesn't need zero it's lift out totally just enough so LV isn't struggling to counter any lift. 
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: baldusi on 06/20/2022 09:35 pm
The fact that DC will not have a fully enclosing fairing, does not means it will have none. If you see the Atlas V renders you will note an aerodynamic adapter that goes above the engines plane. Such adapter can be designed to (mostly) null the asymmetric forces on the LV. The shear stress on the ship and adapter will of course stay.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Rondaz on 06/21/2022 05:05 pm
Sierra Space signs agreement for Dream Chaser landings at Spaceport America..

https://twitter.com/SpaceNews_Inc/status/1539254719306137601
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: JAFO on 09/06/2022 08:04 am
https://www.youtube.com/watch?v=g-uvxzrerzM&t=3s&ab_channel=SierraSpace (https://www.youtube.com/watch?v=g-uvxzrerzM&t=3s&ab_channel=SierraSpace)


 Grrrr….
Please tell Campaign Director Klint Combs that
0:47 It doesn’t come in at a steep angle of attack, it comes in at a steep descent angle.
0:50 It won’t “feather” just before touchdown, it will roundout and flare just before touchdown.
 
 
Please, SNC, there are so many of us who would kill to be in these people’s shoes  and are rooting you on (Yes, I have a DC t-shirt and wear it at my hangar while working on my plane), please please please don’t ruin the excitement by letting your engineers use the incorrect terminology in the promotional videos!!
 
 
10 Dream Chasers….. I cannot wait.
 
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Robotbeat on 09/06/2022 06:54 pm
It’d be sweet if there was a big version of Dream Chaser that had its own methalox propulsion so it could be its own upper stage. That way you could do fully reusable crew or cargo missions with it off of Falcon 9, Neutron, New Glenn, etc.

Also could refuel and fly to Gateway or wherever.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Robotbeat on 09/06/2022 06:56 pm
Sierra Space signs agreement for Dream Chaser landings at Spaceport America..

https://twitter.com/SpaceNews_Inc/status/1539254719306137601
The dreams of the early 00s New Space folk are being vindicated.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Lampyridae on 09/15/2022 11:58 am
It’d be sweet if there was a big version of Dream Chaser that had its own methalox propulsion so it could be its own upper stage. That way you could do fully reusable crew or cargo missions with it off of Falcon 9, Neutron, New Glenn, etc.

Also could refuel and fly to Gateway or wherever.

Now that would be a great Farscape module.

Indeed, given the scale of the LIFE module, Sierra seems like it's aiming big. But maybe they would aim for a recoverable or extremely cheap 2nd stage.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Rondaz on 10/17/2022 01:28 am
Dream Chaser's Expected Launch Date, Progress, Delays, & More

https://youtu.be/UsgMAw6Y_Z4
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: JAFO on 10/17/2022 03:36 am
Dream Chaser's Expected Launch Date, Progress, Delays, & More

^^^^^

No offense but since it's not an official SNC video, just a mashup of previously released stuff, anything in there about a launch date is just speculation.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Ronsmytheiii on 11/16/2022 08:20 pm

 Grrrr….
Please tell Campaign Director Klint Combs that
0:47 It doesn’t come in at a steep angle of attack, it comes in at a steep descent angle.
0:50 It won’t “feather” just before touchdown, it will roundout and flare just before touchdown.
 
 
Please, SNC, there are so many of us who would kill to be in these people’s shoes  and are rooting you on (Yes, I have a DC t-shirt and wear it at my hangar while working on my plane), please please please don’t ruin the excitement by letting your engineers use the incorrect terminology in the promotional videos!!
 
 
10 Dream Chasers….. I cannot wait.
 

Umm, the X-37B has landed on the SLF three times since 2011.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Rocket Science on 12/19/2022 04:33 pm
https://www.youtube.com/watch?v=NFEHh_n7PwY
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Steven Pietrobon on 12/20/2022 04:13 am
The video says the Dream Chaser attitude control thrusters operate in three modes; low, medium and high thrust. For low and medium thrust HTP only is used. For high thrust, they also inject RP-1 into the thruster. They also have a test stand for their hydrolox 156 kN engine.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: tyrred on 01/06/2023 11:21 pm
quote autho ;D >:(r=Conexion Espacial link=topic=29416.msg2446839#msg2446839 date=1673039099]

A view of the Dream Chaser 100 and 200, the latter being the crewed version.https://twitter.com/sierraspaceco/status/1611432910438993930
[/quote]

Did DC 200 crewed version go on diet? Where did the cockpit go?
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Gliderflyer on 01/06/2023 11:44 pm
Forget diet, it looks like it turned into an X-37
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Steven Pietrobon on 01/07/2023 01:42 am
The second version looks quite different.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Asteroza on 01/07/2023 02:11 am
The second version looks quite different.

No cockpit hump?
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Gliderflyer on 01/07/2023 02:14 am
The second version looks quite different.

No cockpit hump?
That and also wings
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Zed_Noir on 01/08/2023 02:28 pm
<snip>
Did DC 200 crewed version go on diet? Where did the cockpit go?
Guess Sierra Space gone the virtual cockpit route and got rid of the windows and replace them with cameras. Simplified building future versions of the Dreamchaser and probably improves the aerodynamic characteristics on ascent exposed on top of a rocket.

The second version looks quite different.
No cockpit hump?
That and also wings
Maybe Sierra Space need the wings for launch abort. Always wonder how a lifting body does attitude orientation after launch abort separation.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Robert_the_Doll on 01/08/2023 04:41 pm
Quote from: Zed_Noir
Maybe Sierra Space need the wings for launch abort. Always wonder how a lifting body does attitude orientation after launch abort separation.

Then you might wish to look at the launch abort studies here (https://books.google.com/books?id=G4Q4AQAAIAAJ&pg=PA1&lpg=PA1&dq=HL-20+launch+mass&source=bl&ots=gOesFuvvoG&sig=ACfU3U0PYBq7zOg1DKnUAdHmKv_mPkiRYw&hl=en&sa=X&ved=2ahUKEwjbgeiTquXzAhXMJt8KHSzFCFUQ6AF6BAgUEAM#v=onepage&q=HL-20%20launch%20mass&f=false) and here (http://www2.coe.pku.edu.cn/tpic/2011721145939517.pdf) for the HL-20.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: AlexP on 01/08/2023 09:32 pm
Would be sad not to see the HL-20 derived DC carry any crew per its original conception, and am curious as to why they'd move on from that design when they're just about to get a lot of actual flight experience with it. Hard to tell with the angle and lighting in that shot, but does seem more like a mix between X-33 and X-37. Hopefully they don't just drop that image and refuse to elaborate for years!
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Markstark on 01/09/2023 12:20 am
Perhaps the rendering is of a subscale version of the new crew variant and that’s why it looks so small and there doesn’t appear to be a traditional cockpit.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: GWH on 01/09/2023 01:57 am
Seems like a pretty significant loss of headroom?

The current dream chase mold isn't particularly tall itself, old cross section for comparison:


Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Lee Jay on 01/09/2023 02:38 am
Perhaps the rendering is of a subscale version of the new crew variant and that’s why it looks so small and there doesn’t appear to be a traditional cockpit.

It looks small because it's farther away. Look at the nose gear contact with the (virtual) ground.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: JAFO on 01/09/2023 03:59 am
Perhaps the rendering is of a subscale version of the new crew variant and that’s why it looks so small and there doesn’t appear to be a traditional cockpit.

It looks small because it's farther away. Look at the nose gear contact with the (virtual) ground.
I was wondering if anyone else would catch the forced perspective in the image.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Star One on 01/09/2023 04:55 pm
Dream Chaser - The Dream Of Lifting Body Space Planes:

https://youtu.be/LK0XZjQf7AM
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Steven Pietrobon on 01/11/2023 05:38 am
Dream Chaser - The Dream Of Lifting Body Space Planes:

Scott forgot to mention the SV-5D PRIME lifting bodies launched by the USAF from 1966 to 1967!

https://www.nationalmuseum.af.mil/Visit/Museum-Exhibits/Fact-Sheets/Display/Article/195893/sv-5d-prime-lifting-body/
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: edzieba on 01/11/2023 08:14 am
Dream Chaser - The Dream Of Lifting Body Space Planes:

Scott forgot to mention the SV-5D PRIME lifting bodies launched by the USAF from 1966 to 1967!

https://www.nationalmuseum.af.mil/Visit/Museum-Exhibits/Fact-Sheets/Display/Article/195893/sv-5d-prime-lifting-body/
And the earlier ASSET, which had a flat-bottomed sliced-cone form (like the X-20, but squashed end-to-end) that has not been used for any other re-entry body since.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Timber Micka on 01/11/2023 09:33 am
Seems like a pretty significant loss of headroom?

The current dream chase mold isn't particularly tall itself, old cross section for comparison:

I expect the crew members to be in the recumbent position as that was planned in the ISS Crew Return Vehicle, which is the closest we've had to a manned lifting body spacecraft.

[EDIT] One more thing Scott didn't mention in his, shall I say, kinda cheap video.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: edzieba on 01/11/2023 09:42 am
Seems like a pretty significant loss of headroom?

The current dream chase mold isn't particularly tall itself, old cross section for comparison:

I expect the crew members to be in the recumbent position as that was planned in the ISS Crew Return Vehicle, which is the closest we've had to a manned lifting body spacecraft.

[EDIT] One more thing Scott didn't mention in his, shall I say, kinda cheap video.
Whilst not using that particular file photo, the LaRC was explicitly shown and its use as a human-factors mockup described, as well as noting that that same mockup later became the Dream Chaser mockup.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Star One on 01/11/2023 11:44 am
Seems like a pretty significant loss of headroom?

The current dream chase mold isn't particularly tall itself, old cross section for comparison:

I expect the crew members to be in the recumbent position as that was planned in the ISS Crew Return Vehicle, which is the closest we've had to a manned lifting body spacecraft.

[EDIT] One more thing Scott didn't mention in his, shall I say, kinda cheap video.
Calling his video cheap, when it’s still informative, is a cheap shot. I mean you can hardly expect Hollywood production from an individual reporter.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Timber Micka on 01/11/2023 02:48 pm
Seems like a pretty significant loss of headroom?

The current dream chase mold isn't particularly tall itself, old cross section for comparison:

I expect the crew members to be in the recumbent position as that was planned in the ISS Crew Return Vehicle, which is the closest we've had to a manned lifting body spacecraft.

[EDIT] One more thing Scott didn't mention in his, shall I say, kinda cheap video.
Calling his video cheap, when it’s still informative, is a cheap shot. I mean you can hardly expect Hollywood production from an individual reporter.

There's no cheap shot here, it's just that people tend to systematically repost his videos without really questioning their real value, just because, you know, he's the famous YouTube guy who talks about space.
It's not often said, but the quality level of his videos is inconsistent, and this video is a perfect example of that.
He forgets 3 important points in the history of the development of lifting bodies, in his video about the history of the development of lifting bodies. Sorry but now that's cheap, and the criticism is fair. I don't know why, but lately some people don't want constructive criticism online anymore.
I'm not expecting "Hollywood production", just something more than reading Wikipedia, Astronautix or Nasaspaceflight pages with a few non-scripted passages, all shot in one take. 'Cause that's what some of his videos are, including this one.

Seems like a pretty significant loss of headroom?

The current dream chase mold isn't particularly tall itself, old cross section for comparison:

I expect the crew members to be in the recumbent position as that was planned in the ISS Crew Return Vehicle, which is the closest we've had to a manned lifting body spacecraft.

[EDIT] One more thing Scott didn't mention in his, shall I say, kinda cheap video.
Whilst not using that particular file photo, the LaRC was explicitly shown and its use as a human-factors mockup described, as well as noting that that same mockup later became the Dream Chaser mockup.

The CRV was not.
You are mistaken, the photo I posted is not a photo of the LaRC HL-20 mockup.
It's a pic of the X-38 aka the Crew Return Vehicle which is a different and distinct, more important lifting-body project from the late 90's/very early 2000's that got really close to flying (a flight model was left 90% completed)
See, this is proof that he clearly wasn't specific enough since you were misled about it.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: GWH on 01/11/2023 02:59 pm
I expect the crew members to be in the recumbent position as that was planned in the ISS Crew Return Vehicle, which is the closest we've had to a manned lifting body spacecraft.

To me this seems less than ideal for a human during launch, I wouldn't want my legs above my head during high acceleration.


Of course as others pointed out it could be it isn't that small and just an odd choice of perspective.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Star One on 01/11/2023 06:13 pm
Seems like a pretty significant loss of headroom?

The current dream chase mold isn't particularly tall itself, old cross section for comparison:

I expect the crew members to be in the recumbent position as that was planned in the ISS Crew Return Vehicle, which is the closest we've had to a manned lifting body spacecraft.

[EDIT] One more thing Scott didn't mention in his, shall I say, kinda cheap video.
Calling his video cheap, when it’s still informative, is a cheap shot. I mean you can hardly expect Hollywood production from an individual reporter.

There's no cheap shot here, it's just that people tend to systematically repost his videos without really questioning their real value, just because, you know, he's the famous YouTube guy who talks about space.
It's not often said, but the quality level of his videos is inconsistent, and this video is a perfect example of that.
He forgets 3 important points in the history of the development of lifting bodies, in his video about the history of the development of lifting bodies. Sorry but now that's cheap, and the criticism is fair. I don't know why, but lately some people don't want constructive criticism online anymore.
I'm not expecting "Hollywood production", just something more than reading Wikipedia, Astronautix or Nasaspaceflight pages with a few non-scripted passages, all shot in one take. 'Cause that's what some of his videos are, including this one.

Seems like a pretty significant loss of headroom?

The current dream chase mold isn't particularly tall itself, old cross section for comparison:

I expect the crew members to be in the recumbent position as that was planned in the ISS Crew Return Vehicle, which is the closest we've had to a manned lifting body spacecraft.

[EDIT] One more thing Scott didn't mention in his, shall I say, kinda cheap video.
Whilst not using that particular file photo, the LaRC was explicitly shown and its use as a human-factors mockup described, as well as noting that that same mockup later became the Dream Chaser mockup.

The CRV was not.
You are mistaken, the photo I posted is not a photo of the LaRC HL-20 mockup.
It's a pic of the X-38 aka the Crew Return Vehicle which is a different and distinct, more important lifting-body project from the late 90's/very early 2000's that got really close to flying (a flight model was left 90% completed)
See, this is proof that he clearly wasn't specific enough since you were misled about it.
I’d rather take his reporting on the topic than some unknown random poster on here who isn’t among the known names on this forum.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Skyrocket on 01/12/2023 12:02 am
Dream Chaser - The Dream Of Lifting Body Space Planes:

Scott forgot to mention the SV-5D PRIME lifting bodies launched by the USAF from 1966 to 1967!

https://www.nationalmuseum.af.mil/Visit/Museum-Exhibits/Fact-Sheets/Display/Article/195893/sv-5d-prime-lifting-body/

Yes, this is often forgotten.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Skyrocket on 01/12/2023 12:03 am
Dream Chaser - The Dream Of Lifting Body Space Planes:

Scott forgot to mention the SV-5D PRIME lifting bodies launched by the USAF from 1966 to 1967!

https://www.nationalmuseum.af.mil/Visit/Museum-Exhibits/Fact-Sheets/Display/Article/195893/sv-5d-prime-lifting-body/
And the earlier ASSET, which had a flat-bottomed sliced-cone form (like the X-20, but squashed end-to-end) that has not been used for any other re-entry body since.

ASSET was more related to DynaSoar than the other real lifting bodies.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: yg1968 on 01/12/2023 04:25 pm
<snip>
Did DC 200 crewed version go on diet? Where did the cockpit go?
Guess Sierra Space gone the virtual cockpit route and got rid of the windows and replace them with cameras. Simplified building future versions of the Dreamchaser and probably improves the aerodynamic characteristics on ascent exposed on top of a rocket.

NASA currently requires windows for commercial crew transportation systems.

Quote from: pages 69 and 70 of CCT-REQ-1130
3.8.4.4 Windows for Crew Tasks

The spacecraft shall provide windows that are available for use by the crew through all phases of flight that provide direct, non-electronic, through-the-hull viewing and the unobstructed fields of-view necessary to perform crew viewing tasks. [R.CTS.177]

Rationale: Windows provide direct, non-electronic, through-the-hull viewing and are essential to mission safety and success, as well as to maintaining crew situational awareness and psychological and physical health and safety. They do not have the failure modes associated with cameras and display systems that may not be operable during emergencies when most needed and are essential for piloting and photography. They also permit stellar navigation, vehicle anomaly detection and inspection, and environmental and scientific observations. NASA experience is that two piloting windows are required to achieve the field of view necessary to accomplish the breadth of piloting tasks. Because of the criticality of windows to crew safety and success of the mission, windows must be a part of the spacecraft design and available through all flight phases without obstructions to their use. Fixed equipment, such as window instrumentation, hardware, or a condensation prevention system, that would obstruct or obscure the field-of-view of the window from the normal crew viewing position will interfere with crew tasks and must not be placed within the sight lines through the window; however, the following are not considered obstructions: hardware used in conjunction with piloting, such as a head's up display (HUD), crew optical alignment system (COAS), or other similar equipment; the outer mold line and hull structure of the vehicle itself; other windows and window mullions; and instrumentation applied to the window itself within 13 mm (~0.5 in.) of the perimeter of the clear viewing area. For detailed design considerations for inboard and outboard window view obscuration exclusion zones, consult Sections 8.6.3.3 and 8.6.3.4 in NASA/SP-2010-3407, Human Integration Design Handbook (HIDH), which also provides extensive guidance for window design considerations.

https://forum.nasaspaceflight.com/index.php?topic=26489.msg1650808#msg1650808
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: yg1968 on 01/12/2023 05:13 pm
Apparently the windows might be on top of the spacecraft and on the hatch. That would make sense since NASA requires a window on the hatch and windows on the spacecraft that is unobstructed for all flight phases for crew viewing tasks. NASA says that in its experience two piloting windows are required (source: pages 69 and 70 of the 2017 version of CCT-REQ-1130 linked in the post above).

https://twitter.com/systems_zero/status/1613591731559178240

Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Lee Jay on 01/12/2023 05:56 pm
I spoke face-to-face with Steve Lindsey about this.  He was pushing for windows on the sides/top etc. for viewing reasons, but virtual synthetic vision for the pilots.  The reason was window closeouts on the front are harder since the temperatures are higher during entry.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: BrightLight on 01/12/2023 07:07 pm
I spoke face-to-face with Steve Lindsey about this.  He was pushing for windows on the sides/top etc. for viewing reasons, but virtual synthetic vision for the pilots.  The reason was window closeouts on the front are harder since the temperatures are higher during entry.
Thank you for confirming that the DC-200 is more like the Boeing x-37(C?) than the HL-20/Dream Chaser - is there a reason for the change in aerodynamic SHAPE? Is it L/D?
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Lee Jay on 01/12/2023 07:45 pm
I spoke face-to-face with Steve Lindsey about this.  He was pushing for windows on the sides/top etc. for viewing reasons, but virtual synthetic vision for the pilots.  The reason was window closeouts on the front are harder since the temperatures are higher during entry.
Thank you for confirming that the DC-200 is more like the Boeing x-37(C?) than the HL-20/Dream Chaser - is there a reason for the change in aerodynamic SHAPE? Is it L/D?

I know nothing of the change in shape.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: gemmy0I on 01/12/2023 10:38 pm
NASA currently requires windows for commercial crew transportation systems.

Quote from: pages 69 and 70 of CCT-REQ-1130
3.8.4.4 Windows for Crew Tasks

... Because of the criticality of windows to crew safety and success of the mission, windows must be a part of the spacecraft design and available through all flight phases without obstructions to their use. Fixed equipment, such as window instrumentation, hardware, or a condensation prevention system, that would obstruct or obscure the field-of-view of the window from the normal crew viewing position will interfere with crew tasks and must not be placed within the sight lines through the window; however, the following are not considered obstructions: hardware used in conjunction with piloting, such as a head's up display (HUD), crew optical alignment system (COAS), or other similar equipment; the outer mold line and hull structure of the vehicle itself; other windows and window mullions; and instrumentation applied to the window itself within 13 mm (~0.5 in.) of the perimeter of the clear viewing area.
Somewhat off-topic (since this obviously wouldn't apply to Dream Chaser in any case, but would've been relevant to other Commercial Crew entrants like Dragon and Starliner that use more traditional capsules): if I'm reading this correctly, would this preclude an Orion- or Soyuz-style "tractor" abort motor tower that covers the windows with a fairing during early launch phases? A natural reading of "available through all flight phases" would suggest as such, but perhaps there is other context that excludes launch phases from this definition.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: yg1968 on 01/13/2023 02:15 am
Somewhat off-topic (since this obviously wouldn't apply to Dream Chaser in any case, but would've been relevant to other Commercial Crew entrants like Dragon and Starliner that use more traditional capsules): if I'm reading this correctly, would this preclude an Orion- or Soyuz-style "tractor" abort motor tower that covers the windows with a fairing during early launch phases? A natural reading of "available through all flight phases" would suggest as such, but perhaps there is other context that excludes launch phases from this definition.

I am not sure but the requirement is the following:

Quote from: page 69 of CCT-REQ-1130
The spacecraft shall provide windows that are available for use by the crew through all phases of flight that provide direct, non-electronic, through-the-hull viewing and the unobstructed fields of-view necessary to perform crew viewing tasks. [R.CTS.177]

The rest of the text is the rationale for the requirement. I am not sure if the ascent would require an unobstructed view in order to perform a crew viewing task. It's not clear to me what is a crew viewing task and if there is such a task on ascent.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: edzieba on 01/13/2023 11:35 am
if I'm reading this correctly, would this preclude an Orion- or Soyuz-style "tractor" abort motor tower that covers the windows with a fairing during early launch phases?
Not if they use the solution implemented on Apollo's 'Boost Protective Cover': adding a window in the cover (over the hatch window in that case). 
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: JEF_300 on 01/14/2023 04:41 am
Quoting from the update thread:

The caption of the DC-201 in orbit image has some additional details.

Quote from: the caption
Differentiated from the DC-100 series by a 40% increase in size, upper body windows and fixed wings, the redesigned DC-200 is expected to be flight-tested without a crew in late 2025 - and with astronauts onboard in 2026. Although design details are yet to be finalized, the DC-200 is likely to be configured with lower body-mounted wings and twin-canted tails, similar to the Boeing X-37, and will feature a simpler outer mold line without the pronounced upper-body hump of the baseline version.

Well, when put that way, it almost sounds as if it's not just a completely different shape. Almost.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: AlexP on 01/14/2023 12:48 pm
Copied over the pics from the updates thread.

2025 seems pretty optimistic, is a beauty though.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: oldAtlas_Eguy on 01/14/2023 04:48 pm
Is there a max crew compliment for the DC-201? At ~40% larger it should have more habitat volume space. Also even though it's mass increased. It could still be increased some more before outgrowing current Vulcan and reusable NG capabilities.

If a version of DC eventually gets to crew sizes above 12. The vehicle would be quite popular with the "tourist to LEO" market. Also it would enable LEO permanent Space Station crew sizes of >20. But such is unlikely to occur this decade. But next decade?
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: jdon759 on 01/16/2023 09:17 am
Assuming wheels and landing skid are the same size, here's a very approximate perspective-corrected image
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Zed_Noir on 01/27/2023 09:12 pm
Is there a max crew compliment for the DC-201? At ~40% larger it should have more habitat volume space. Also even though it's mass increased. It could still be increased some more before outgrowing current Vulcan and reusable NG capabilities.

If a version of DC eventually gets to crew sizes above 12. The vehicle would be quite popular with the "tourist to LEO" market. Also it would enable LEO permanent Space Station crew sizes of >20. But such is unlikely to occur this decade. But next decade?
Think the DC-201 got an internal cabin width wide enough for 3 abreast seating. So maybe a seating layout of 2 seats for the flight crew in the front, 4 row of 3 seats in the middle for passengers and one optional seat in the back for cabin attendant/loadmaster.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: adrianwyard on 01/27/2023 09:41 pm
DC 201 is definitely a looker, so hopefully more than just an artist's impression. I have my doubts. If it really is the next version, some questions:

+ What launches it? (no folding wings?) Maybe it fits inside a 7m New Glenn fairing?
+ Does it have an abort motor/option, or still none? While the cargo DC may gain some reliability statics where you'd eventually be OK putting crew on it, this would be a new vehicle.
+ landing speed? Just eyeballing it I'd guess it would have to be much faster than first DC. If not super fast I'm not sure how you stop the nose slamming down with center of lift so far back. Longer runway required?
+ Is this even still a lifting body?
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: abaddon on 01/28/2023 12:43 am
Better question: who’s paying for it?
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: adrianwyard on 01/28/2023 04:18 am
Always a good question. But Blue Origin does need an orbital crewed spacecraft for their Reef ambitions, so that's a good place to start. This could be a study/concept partly informed by Blue's feedback on DC 1.0, i.e. how it stacks up compared with their ideal vehicle.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: whitelancer64 on 02/01/2023 05:19 pm
DC 201 is definitely a looker, so hopefully more than just an artist's impression. I have my doubts. If it really is the next version, some questions:

+ What launches it? (no folding wings?) Maybe it fits inside a 7m New Glenn fairing?
+ Does it have an abort motor/option, or still none? While the cargo DC may gain some reliability statics where you'd eventually be OK putting crew on it, this would be a new vehicle.
+ landing speed? Just eyeballing it I'd guess it would have to be much faster than first DC. If not super fast I'm not sure how you stop the nose slamming down with center of lift so far back. Longer runway required?
+ Is this even still a lifting body?

Ariane 6, Falcon Heavy, New Glenn, or Vulcan would be capable of launching it. 

Like the original Dream Chaser, if launched with a crew then there would be no fairing, and launch abort would be performed by firing all of the main engines (there are 8 of them in the render). 

It will flare the nose up on landing to touch down on wheels. Probably does require a longer runway to land.

I think it's still a lifting body based on its shape, it just has some short wings as well.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: vt_hokie on 02/04/2023 12:59 am

I think it's still a lifting body based on its shape, it just has some short wings as well.

Almost reminds me of the evolution of the VentureStar which, while perhaps never realistic or viable, did start to evolve beyond the X-33 shape with larger wings before that whole effort was officially cancelled. 
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Lampyridae on 02/08/2023 08:20 am
Somewhat off-topic (since this obviously wouldn't apply to Dream Chaser in any case, but would've been relevant to other Commercial Crew entrants like Dragon and Starliner that use more traditional capsules): if I'm reading this correctly, would this preclude an Orion- or Soyuz-style "tractor" abort motor tower that covers the windows with a fairing during early launch phases? A natural reading of "available through all flight phases" would suggest as such, but perhaps there is other context that excludes launch phases from this definition.

I am not sure but the requirement is the following:

Quote from: page 69 of CCT-REQ-1130
The spacecraft shall provide windows that are available for use by the crew through all phases of flight that provide direct, non-electronic, through-the-hull viewing and the unobstructed fields of-view necessary to perform crew viewing tasks. [R.CTS.177]

The rest of the text is the rationale for the requirement. I am not sure if the ascent would require an unobstructed view in order to perform a crew viewing task. It's not clear to me what is a crew viewing task and if there is such a task on ascent.

The QueSST doesn't have forward cockpit windows either.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Alpha Control on 02/20/2023 11:52 pm
Somewhat off-topic (since this obviously wouldn't apply to Dream Chaser in any case, but would've been relevant to other Commercial Crew entrants like Dragon and Starliner that use more traditional capsules): if I'm reading this correctly, would this preclude an Orion- or Soyuz-style "tractor" abort motor tower that covers the windows with a fairing during early launch phases? A natural reading of "available through all flight phases" would suggest as such, but perhaps there is other context that excludes launch phases from this definition.

I am not sure but the requirement is the following:

Quote from: page 69 of CCT-REQ-1130
The spacecraft shall provide windows that are available for use by the crew through all phases of flight that provide direct, non-electronic, through-the-hull viewing and the unobstructed fields of-view necessary to perform crew viewing tasks. [R.CTS.177]

The rest of the text is the rationale for the requirement. I am not sure if the ascent would require an unobstructed view in order to perform a crew viewing task. It's not clear to me what is a crew viewing task and if there is such a task on ascent.

The QueSST doesn't have forward cockpit windows either.

The Shuttle engineers in the 1970s figured out how to do to forward facing windows. I don't understand why this suddenly seems to be so difficult, and that overhead windows are the only way to have windows?? Am I missing something? Thanks.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: adrianwyard on 02/21/2023 02:10 am
For the current Dream Chaser design I suspect it comes down to trade studies showing the benefits of adding forward cockpit style windows do not outweigh the costs. The costs being mainly weight, maintenance (an issue for Shuttle) but perhaps also structural margins if there are lots of them. To nix windows such a study would need to place great confidence in synthetic vision and/or automated landing, which would have been controversial a decade ago but not so much now.

For QueSST (and probably the DC-201 as pictured) forward windows would not allow you to see over the nose when landing, so that's a fine reason to delete them.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: JAFO on 02/21/2023 03:46 am
Somewhat off-topic (since this obviously wouldn't apply to Dream Chaser in any case, but would've been relevant to other Commercial Crew entrants like Dragon and Starliner that use more traditional capsules): if I'm reading this correctly, would this preclude an Orion- or Soyuz-style "tractor" abort motor tower that covers the windows with a fairing during early launch phases? A natural reading of "available through all flight phases" would suggest as such, but perhaps there is other context that excludes launch phases from this definition.

I am not sure but the requirement is the following:

Quote from: page 69 of CCT-REQ-1130
The spacecraft shall provide windows that are available for use by the crew through all phases of flight that provide direct, non-electronic, through-the-hull viewing and the unobstructed fields of-view necessary to perform crew viewing tasks. [R.CTS.177]

The rest of the text is the rationale for the requirement. I am not sure if the ascent would require an unobstructed view in order to perform a crew viewing task. It's not clear to me what is a crew viewing task and if there is such a task on ascent.

The QueSST doesn't have forward cockpit windows either.

The Shuttle engineers in the 1970s figured out how to do to forward facing windows. I don't understand why this suddenly seems to be so difficult, and that overhead windows are the only way to have windows?? Am I missing something? Thanks.

Wonder if it's the same people who said there was no longer a need for a gun in a fighter because missiles were so reliable?

With that said, I've shot enough Cat III autoland approaches to know that modern systems are reliable enough that I don't really need to see outside to land if everything is working right. But it's still freaky, and I don't think I'd ever feel comfortable doing one with my hands in my lap. Just too many ways for things to go wrong.


 
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Lee Jay on 02/21/2023 12:17 pm
For the current Dream Chaser design I suspect it comes down to trade studies showing the benefits of adding forward cockpit style windows do not outweigh the costs. The costs being mainly weight, maintenance (an issue for Shuttle) but perhaps also structural margins if there are lots of them. To nix windows such a study would need to place great confidence in synthetic vision and/or automated landing, which would have been controversial a decade ago but not so much now.

For QueSST (and probably the DC-201 as pictured) forward windows would not allow you to see over the nose when landing, so that's a fine reason to delete them.

IIRC, Steve Lindsey said forward windows cost on the order of 500 pounds of cargo mass.  Ouch.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: edzieba on 02/21/2023 02:24 pm
Somewhat off-topic (since this obviously wouldn't apply to Dream Chaser in any case, but would've been relevant to other Commercial Crew entrants like Dragon and Starliner that use more traditional capsules): if I'm reading this correctly, would this preclude an Orion- or Soyuz-style "tractor" abort motor tower that covers the windows with a fairing during early launch phases? A natural reading of "available through all flight phases" would suggest as such, but perhaps there is other context that excludes launch phases from this definition.

I am not sure but the requirement is the following:

Quote from: page 69 of CCT-REQ-1130
The spacecraft shall provide windows that are available for use by the crew through all phases of flight that provide direct, non-electronic, through-the-hull viewing and the unobstructed fields of-view necessary to perform crew viewing tasks. [R.CTS.177]

The rest of the text is the rationale for the requirement. I am not sure if the ascent would require an unobstructed view in order to perform a crew viewing task. It's not clear to me what is a crew viewing task and if there is such a task on ascent.

The QueSST doesn't have forward cockpit windows either.

The Shuttle engineers in the 1970s figured out how to do to forward facing windows. I don't understand why this suddenly seems to be so difficult, and that overhead windows are the only way to have windows?? Am I missing something? Thanks.
The Orbiter windows mere multiple layers of different (and expensive, and heavy) glasses, along with desiccant and purge systems to allow those windows to be optically useful when going from STP to vacuum through entry and back again - because windows that spent their time fogged or with ice formed inside them are not much good as windows.
Windows as that don't face right into entry plasma flow and are not safety critical are reasonable to add. Windows that both receive a significant portion of entry heating and are a safety critical system are not so trivial. A camera + display system has the opportunity to be both lighter mass, cheaper, and have additional redundancy (multiple cameras and displays).
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: TrevorMonty on 02/21/2023 04:02 pm


Somewhat off-topic (since this obviously wouldn't apply to Dream Chaser in any case, but would've been relevant to other Commercial Crew entrants like Dragon and Starliner that use more traditional capsules): if I'm reading this correctly, would this preclude an Orion- or Soyuz-style "tractor" abort motor tower that covers the windows with a fairing during early launch phases? A natural reading of "available through all flight phases" would suggest as such, but perhaps there is other context that excludes launch phases from this definition.

I am not sure but the requirement is the following:

Quote from: page 69 of CCT-REQ-1130
The spacecraft shall provide windows that are available for use by the crew through all phases of flight that provide direct, non-electronic, through-the-hull viewing and the unobstructed fields of-view necessary to perform crew viewing tasks. [R.CTS.177]

The rest of the text is the rationale for the requirement. I am not sure if the ascent would require an unobstructed view in order to perform a crew viewing task. It's not clear to me what is a crew viewing task and if there is such a task on ascent.

The QueSST doesn't have forward cockpit windows either.

The Shuttle engineers in the 1970s figured out how to do to forward facing windows. I don't understand why this suddenly seems to be so difficult, and that overhead windows are the only way to have windows?? Am I missing something? Thanks.

Wonder if it's the same people who said there was no longer a need for a gun in a fighter because missiles were so reliable?

With that said, I've shot enough Cat III autoland approaches to know that modern systems are reliable enough that I don't really need to see outside to land if everything is working right. But it's still freaky, and I don't think I'd ever feel comfortable doing one with my hands in my lap. Just too many ways for things to go wrong.

Flyby wire controls can also fail in which case window is only useful to see your end.

Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: niwax on 02/21/2023 04:13 pm


Somewhat off-topic (since this obviously wouldn't apply to Dream Chaser in any case, but would've been relevant to other Commercial Crew entrants like Dragon and Starliner that use more traditional capsules): if I'm reading this correctly, would this preclude an Orion- or Soyuz-style "tractor" abort motor tower that covers the windows with a fairing during early launch phases? A natural reading of "available through all flight phases" would suggest as such, but perhaps there is other context that excludes launch phases from this definition.

I am not sure but the requirement is the following:

Quote from: page 69 of CCT-REQ-1130
The spacecraft shall provide windows that are available for use by the crew through all phases of flight that provide direct, non-electronic, through-the-hull viewing and the unobstructed fields of-view necessary to perform crew viewing tasks. [R.CTS.177]

The rest of the text is the rationale for the requirement. I am not sure if the ascent would require an unobstructed view in order to perform a crew viewing task. It's not clear to me what is a crew viewing task and if there is such a task on ascent.

The QueSST doesn't have forward cockpit windows either.

The Shuttle engineers in the 1970s figured out how to do to forward facing windows. I don't understand why this suddenly seems to be so difficult, and that overhead windows are the only way to have windows?? Am I missing something? Thanks.

Wonder if it's the same people who said there was no longer a need for a gun in a fighter because missiles were so reliable?

With that said, I've shot enough Cat III autoland approaches to know that modern systems are reliable enough that I don't really need to see outside to land if everything is working right. But it's still freaky, and I don't think I'd ever feel comfortable doing one with my hands in my lap. Just too many ways for things to go wrong.

Flyby wire controls can also fail in which case window is only useful to see your end.

If you have any kind of control failure you're going to be in trouble. It's the classic spaceplane fallacy, just because it looks like a plane and those land safely doesn't mean it applies to space. This thing comes down on a several thousand kilometer unpowered glide, actually reentering butt first, with no possibility of going around or holding while you run a checklist.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: tbellman on 02/21/2023 04:29 pm
Flyby wire controls can also fail in which case window is only useful to see your end.

But will DreamChaser actually be controllable by the crew during descent and landing?  Or will it be entirely autonomous?  In the latter case, it doesn't matter how well the crew can see outside through the windows; if the cameras/radar/whatever the computer uses fail, the crew can't do anything anyway.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Lee Jay on 02/21/2023 07:56 pm
Flyby wire controls can also fail in which case window is only useful to see your end.

But will DreamChaser actually be controllable by the crew during descent and landing?  Or will it be entirely autonomous?  In the latter case, it doesn't matter how well the crew can see outside through the windows; if the cameras/radar/whatever the computer uses fail, the crew can't do anything anyway.

Both.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: JAFO on 02/21/2023 11:33 pm

Flyby wire controls can also fail in which case window is only useful to see your end.

If you have any kind of control failure you're going to be in trouble. It's the classic spaceplane fallacy, just because it looks like a plane and those land safely doesn't mean it applies to space. This thing comes down on a several thousand kilometer unpowered glide, actually reentering butt first, with no possibility of going around or holding while you run a checklist.

It reenters belly first, not butt first.

The FBW planes I've flown (13,000+ hours) have a stupid amount of control redundancy, and it all switches over invisibly in the event of a problem. DC does have fewer flight control surfaces than an airliner, it would be interesting to someday find out about their logic in nominal and off-nominal modes.

What keeps me up at night is a software problem. Me and my plane got into an argument the other day and I finally gave Hal a time out and did what I wanted to do manually, it was more of an "art of flying" vs "software logic of flying" debate, which I won.

Understandably, reentry software is far more complicated than climb/level off/descent/landing VNAV, so I'm sure SNC is burning electrons on that. Even something as "simple" as the RJ I used to fly had software problems many years after it was introduced into service. But the risks, rewards, and complexity of a FBW winged/whatever you want to call her vehicle are worth it vs the simplicity of a brutal capsule reentry.

The joke on my current ride is a new guy goes "What's it doing?", and the experienced pilot goes "Hang on, I've seen this shit before...."
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Lee Jay on 02/21/2023 11:44 pm

Flyby wire controls can also fail in which case window is only useful to see your end.

If you have any kind of control failure you're going to be in trouble. It's the classic spaceplane fallacy, just because it looks like a plane and those land safely doesn't mean it applies to space. This thing comes down on a several thousand kilometer unpowered glide, actually reentering butt first, with no possibility of going around or holding while you run a checklist.
The FBW planes I've flown (13,000+ hours) have a stupid amount of control redundancy, and it all switches over invisibly in the event of a problem. What keeps me up at night is a software problem, me and my plane got into an argument the other day and I finally gave Hal a time out and did what I wanted to do manually, it was more of an "art of flying" vs "software logic of flying" debate, which I won. Understandably, reentry software is far more complicated than climb and level of VNAV, so I'm sure SNC is burning electrons on that.

The joke on my plane is a new guy goes Whats it doing?, and the experienced pilot goes Wait, I've seen this shit before....


DC had triple redundancy in the flight controls last time I asked.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Asteroza on 02/22/2023 02:06 am

Flyby wire controls can also fail in which case window is only useful to see your end.

If you have any kind of control failure you're going to be in trouble. It's the classic spaceplane fallacy, just because it looks like a plane and those land safely doesn't mean it applies to space. This thing comes down on a several thousand kilometer unpowered glide, actually reentering butt first, with no possibility of going around or holding while you run a checklist.
The FBW planes I've flown (13,000+ hours) have a stupid amount of control redundancy, and it all switches over invisibly in the event of a problem. What keeps me up at night is a software problem, me and my plane got into an argument the other day and I finally gave Hal a time out and did what I wanted to do manually, it was more of an "art of flying" vs "software logic of flying" debate, which I won. Understandably, reentry software is far more complicated than climb and level of VNAV, so I'm sure SNC is burning electrons on that.

The joke on my plane is a new guy goes Whats it doing?, and the experienced pilot goes Wait, I've seen this shit before....


DC had triple redundancy in the flight controls last time I asked.

Isn't triple redundancy pretty standard for aerospace control-by-wire applications though?
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Robotbeat on 02/25/2023 01:44 am
Somewhat off-topic (since this obviously wouldn't apply to Dream Chaser in any case, but would've been relevant to other Commercial Crew entrants like Dragon and Starliner that use more traditional capsules): if I'm reading this correctly, would this preclude an Orion- or Soyuz-style "tractor" abort motor tower that covers the windows with a fairing during early launch phases? A natural reading of "available through all flight phases" would suggest as such, but perhaps there is other context that excludes launch phases from this definition.

I am not sure but the requirement is the following:

Quote from: page 69 of CCT-REQ-1130
The spacecraft shall provide windows that are available for use by the crew through all phases of flight that provide direct, non-electronic, through-the-hull viewing and the unobstructed fields of-view necessary to perform crew viewing tasks. [R.CTS.177]

The rest of the text is the rationale for the requirement. I am not sure if the ascent would require an unobstructed view in order to perform a crew viewing task. It's not clear to me what is a crew viewing task and if there is such a task on ascent.

The QueSST doesn't have forward cockpit windows either.

The Shuttle engineers in the 1970s figured out how to do to forward facing windows. I don't understand why this suddenly seems to be so difficult, and that overhead windows are the only way to have windows?? Am I missing something? Thanks.
Shuttle's windows were shielded mostly from the fiercest part of the flow, and they were completely flat. QUESST is very carefully shaped in an aerodynamic manner and would require a ridiculously long (and therefore heavy) window due to the very long nose, which is an essential part of its design.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: russianhalo117 on 03/15/2023 01:50 am
DutchSatellites
@DutchSatellites

As expected multiple sources have reported over the past several weeks that
@SierraSpaceCo
 Dream Chaser is no longer manifested on
@ulalaunch
 Vulcan flight #2. Primary reason is yet another set of delays in getting Dream Chaser ready for flight.
1:23 PM · Mar 5, 2023


https://twitter.com/DutchSatellites/status/1632492016465575941
If the second Vulcan launch won't be used to launch the first orbital Dream Chaser, the question is whether it will be repurposed for the launch of USSF-106.
No because NSSL launches require the launcher to be fully certified.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Lampyridae on 03/15/2023 04:30 pm

Flyby wire controls can also fail in which case window is only useful to see your end.

If you have any kind of control failure you're going to be in trouble. It's the classic spaceplane fallacy, just because it looks like a plane and those land safely doesn't mean it applies to space. This thing comes down on a several thousand kilometer unpowered glide, actually reentering butt first, with no possibility of going around or holding while you run a checklist.

It reenters belly first, not butt first.

The FBW planes I've flown (13,000+ hours) have a stupid amount of control redundancy, and it all switches over invisibly in the event of a problem. DC does have fewer flight control surfaces than an airliner, it would be interesting to someday find out about their logic in nominal and off-nominal modes.

What keeps me up at night is a software problem. Me and my plane got into an argument the other day and I finally gave Hal a time out and did what I wanted to do manually, it was more of an "art of flying" vs "software logic of flying" debate, which I won.

Understandably, reentry software is far more complicated than climb/level off/descent/landing VNAV, so I'm sure SNC is burning electrons on that. Even something as "simple" as the RJ I used to fly had software problems many years after it was introduced into service. But the risks, rewards, and complexity of a FBW winged/whatever you want to call her vehicle are worth it vs the simplicity of a brutal capsule reentry.

The joke on my current ride is a new guy goes "What's it doing?", and the experienced pilot goes "Hang on, I've seen this shit before...."

I hear you on the "we don't need guns anymore" argument. Cameras have their own issues such as struggling with high contrast, resolving fast moving objects etc*. At least a periscope would give you a faithful representation of what's out there (as in, direct photons to retinas).

Digital to eyeballs spooks me because it always introduces the problem of software issues, or a bit getting flipped. Now your camera mode is stuck on ISO 80 and you're making a night landing approach that actually requires the human to see what's going.

*of course, this being NSF there's somebody who's personally worked on project XYZ to tell me I'm wrong
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Mdmurphy12 on 03/26/2023 02:33 pm
On the topic of whether there are 6 or 7 Dreamchaser launches under contract, it seems that even Sierra Nevada doesn't know...

They're website page "overview" notes:
"Dream Chaser will provide a minimum of six cargo missions to and from the space station"
https://www.sierraspace.com/space-transportation/

Meanwhile the page specifically on Dreamchaser notes:
"Dream Chaser will provide a minimum of seven cargo service missions to and from the space station."
https://www.sierraspace.com/space-transportation/dream-chaser-spaceplane/

I'd love for one of the journalists on the space beat to get an answer on this once and for all, likely from NASA.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: oldAtlas_Eguy on 03/26/2023 04:57 pm
On the topic of whether there are 6 or 7 Dreamchaser launches under contract, it seems that even Sierra Nevada doesn't know...

They're website page "overview" notes:
"Dream Chaser will provide a minimum of six cargo missions to and from the space station"
https://www.sierraspace.com/space-transportation/

Meanwhile the page specifically on Dreamchaser notes:
"Dream Chaser will provide a minimum of seven cargo service missions to and from the space station."
https://www.sierraspace.com/space-transportation/dream-chaser-spaceplane/

I'd love for one of the journalists on the space beat to get an answer on this once and for all, likely from NASA.
Contract mechanism of solid contract has 6 and also has an unactivated option where dates and quantities can be added by a simple and quick contract mod that exercises the predefined option and prices. The mod basically adds money to the contract for the N number of extra launches. No RFP or evaluation just the contract officer issues the mod.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: joek on 03/26/2023 06:04 pm
On the topic of whether there are 6 or 7 Dreamchaser launches under contract, it seems that even Sierra Nevada doesn't know...
...

Depends on where they are in the on ramp and authority to proceed (ATP) process for specific missions...

Per ISS Commercial Resupply Service 2 (CRS2) NNJ16GX07B (https://www.nasa.gov/sites/default/files/atoms/files/nnj16gx07b_-redacted1.pdf), Jan-2016 (emphasis added):
Quote
I.A.2 INDEFINITE DELIVERY INDEFINITE QUANTITY (IDIQ), FIRM FIXED PRICE CONTRACT
In accordance with Provision VI.A.5, Single or Multiple Awards (FAR 52.216-27) (Oct 1995), NASA may elect to award multiple contracts. The guaranteed minimum value for any awarded contract is six (6) cargo resupply service missions with the capabilities defined for the awarded mission in Table I.A.3-1, Mission Capabilities for the Standard Resupply Services Missions. The total maximum value of any contract awarded will be $14 billion. The total amount of all task orders under all contracts awarded shall not exceed $14 billion.
Of note:
Quote
II.A.6 ON-RAMP
6.1 The guaranteed minimum order amount for IDIQ contracts awarded in accordance with the On-Ramp Clause will be two cargo resupply service missions with the capabilities defined for the awarded mission in Table I.A.3-1, Mission Capabilities for the Standard Resupply Services Missions. The maximum value of IDIQ contracts awarded in accordance with the OnRamp Clause are subject to the limitations defined in Clause I.A.2, Indefinite Delivery Indefinite Quantity (IDIQ), Firm Fixed Price Contract.

In short, minimum of two (2) missions (including-assuming ISS integration is passed), and up to six (6). The reason the exact number is still TBD is because SNC has not passed the gates necessary to get from one to the other. NB: "up to" as this is an IDIQ contract; nothing is guaranteed, which is why SNC's forecast (as anyone under an IDIQ contract), is a bit fuzzy. They still have not made it through the ISS integration gate, so expect any forecasts will remain fuzzy until they get through that gate.

edit: p.s. The 6 vs. 7 missions may be due to one of the ISS Integration demonstration missions being considered as operational delivery (or partial operational delivery). We have seen that with other programs.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: jackvancouver on 04/24/2023 09:29 pm
Might be a stupid question, but in it's currently publicized configuration, would having 2 Dream Chasers connected by a truss and rotating produce enough gravity in it's rotational speed accounting for the strength of where it docks?
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: whitelancer64 on 04/27/2023 04:53 pm
Might be a stupid question, but in it's currently publicized configuration, would having 2 Dream Chasers connected by a truss and rotating produce enough gravity in it's rotational speed accounting for the strength of where it docks?

How much is "enough" gravity?
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: adrianwyard on 04/27/2023 05:57 pm
Is the truss attached at the docking ports in the aft? We know that's robust, and the truss can attached via docking hardware, but rotation would make the nose 'down' in a tall volume. If you picture them attached by the dorsal/roof hatch, that would make down correct but there's no docking hardware there; it's only used for loading/ingress when it's vertical on the pad.

Side note: rotating artificial gravity solutions only become Earthlike when the arm is really long and the rotation slow. If it's short (and fast) there are many weirdnesses that show up when moving around. However, on small craft like Dream Chaser where you can barely stand up they wouldn't surface as much.

But my main question is: why add artificial gravity to Dream Chaser?
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: abaddon on 05/23/2023 09:33 pm
Quote
Sierra Space hosted its first-ever official Dream Chaser training for astronauts, Jasmin Moghbeli (@NASA) and Satoshi Furukawa (@JAXA_en), of the upcoming #SpaceX Crew-7 mission to the @Space_Station.

Press Release:

[snip]
The astronauts – Jasmin Moghbeli (United States) and Satoshi Furukawa (Japan) – are two members of the upcoming SpaceX Crew-7 mission to the International Space Station (ISS). During their planned six-month stay, Dream Chaser will make its maiden voyage to deliver cargo to the ISS as part of NASA’s Commercial Resupply Services-2 (CRS-2) contract.
[snip]

Crew 7 is targeting August, so that would indicate the hope/possibility is that Dream Chaser could make its debut launch to the ISS somewhere in the August-February (if C7 is end of August) time period.  Presumably still a NET.  Maybe we'll get more information about a possible debut launch window in the upcoming months.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Star One on 06/02/2023 08:30 am
I know Dream Chaser has had its own fair share of issues causing delays, but I have to wonder if it would have been a better bet for crewed flight to ISS than Starliner is proving to be.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: DanClemmensen on 06/02/2023 01:19 pm
I know Dream Chaser has had its own fair share of issues causing delays, but I have to wonder if it would have been a better bet for crewed flight to ISS than Starliner is proving to be.
Easy to say in retrospect. However, in 2014 when CCP was awarded, NASA thought Boeing was the conservative "sure thing" choice and SpaceX was the backup "diverse redundancy" choice. to add Dream Chaser, they likely would have removed Crew Dragon.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Cherokee43v6 on 06/02/2023 02:02 pm
I know Dream Chaser has had its own fair share of issues causing delays, but I have to wonder if it would have been a better bet for crewed flight to ISS than Starliner is proving to be.
Easy to say in retrospect. However, in 2014 when CCP was awarded, NASA thought Boeing was the conservative "sure thing" choice and SpaceX was the backup "diverse redundancy" choice. to add Dream Chaser, they likely would have removed Crew Dragon.

I'm not so sure that's true.  I remember, at that time, there was a lot of argument on the board here about what actual 'redundancy' meant.  The fact that Dreamchaser was intended to launch on AtlasV meant that both selections would be dependent upon a single point failure... the launch vehicle.  True redundancy meant that it was going to be SpaceX and either Boeing or Dreamchaser.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: abaddon on 06/02/2023 02:43 pm
DreamChaser has struggled just as much as Starliner and the bar for unscrewed flight is much lower than for a manned capsule.  There’s zero reason to think they’d be done by now any more than Boeing (although at least they would have been a lot cheaper).
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: abaddon on 06/02/2023 02:48 pm
True redundancy meant that it was going to be SpaceX and either Boeing or Dreamchaser.
As we found out later, NASA was very close to selecting only Boeing, so the whole “redundancy” thing in reference to the selection is greatly overblown.  Both vehicles being launched on Atlas V (one of the most reliable launchers in history) wouldn’t have mattered much.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: JEF_300 on 06/02/2023 02:59 pm
DreamChaser has struggled just as much as Starliner and the bar for unscrewed flight is much lower than for a manned capsule.  There’s zero reason to think they’d be done by now any more than Boeing (although at least they would have been a lot cheaper).

A: Dreamchaser has developed about as fast as Starliner has, despite:
    - Boeing having more internal capital and resources than Sierra Nevada/Space
    - A spaceplane being a more difficult engineering challenge than a capsule
B: NASA awarded Boeing more money than they did Sierra Nevada
C: NASA awarded significant funding to Boeing years before doing so with Sierra Nevada

All things considered, I think there's lots of reasons to think they'd be more done by now than Boeing is.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: abaddon on 06/02/2023 03:07 pm
Not having enough capital (yet making a much cheaper bid in an effort to win the contract) and it being harder are terrible arguments to say it’d be done sooner.  Congress slow-rolled commercial crew funding for years, which slowed both SpaceX and Boeing substantially.  There was no such funding delay with DreamChaser.

Worth remembering Boeing actually has two flights under its belt, as problematic as they were, while DreamChaser hasn’t even flown yet.  Maybe wait and see when the inaugural flight happens and how well it goes first?  I do want them to succeed, they just need to actually do it.

Blind optimism is the only reason to think SNC would magically be done sooner than Boeing.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Jim on 06/02/2023 03:47 pm


All things considered, I think there's lots of reasons to think they'd be more done by now than Boeing is.

No, Dreamchaser is still more than a year away for launching a cargo version.  A crew version would be much further away.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: joek on 06/02/2023 06:00 pm
...
All things considered, I think there's lots of reasons to think they'd be more done by now than Boeing is.
Cargo maybe; crew no. Meeting LoC goals has been a challenge for years (https://oiir.hq.nasa.gov/asap/documents/2015_ASAP_Annual_Report.pdf), in large part due to MMOD concerns.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: TrevorMonty on 06/02/2023 06:45 pm


All things considered, I think there's lots of reasons to think they'd be more done by now than Boeing is.

No, Dreamchaser is still more than a year away for launching a cargo version.  A crew version would be much further away.
DC development slowed considerably after SNC lost commercial crew funding. Had they won then crew version should've done its maiden launched while ago. But it didn't win so here we are.

Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Jim on 06/02/2023 06:56 pm


All things considered, I think there's lots of reasons to think they'd be more done by now than Boeing is.

No, Dreamchaser is still more than a year away for launching a cargo version.  A crew version would be much further away.
DC development slowed considerably after SNC lost commercial crew funding. Had they won then crew version should've done its maiden launched while ago. But it didn't win so here we are.

Can’t say that
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: darkenfast on 06/02/2023 07:35 pm
I've yet to see an explanation for how a crewed DC can abort from inside the fairing. The spacecraft is inside there for a reason.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Lee Jay on 06/02/2023 11:26 pm
I've yet to see an explanation for how a crewed DC can abort from inside the fairing. The spacecraft is inside there for a reason.

Crewed version wouldn't be inside a fairing, the last time I asked.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: JAFO on 06/02/2023 11:50 pm
DreamChaser has struggled just as much as Starliner and the bar for unscrewed flight is much lower than for a manned capsule.  There’s zero reason to think they’d be done by now any more than Boeing (although at least they would have been a lot cheaper).

A: Dreamchaser has developed about as fast as Starliner has, despite:
    - Boeing having more internal capital and resources than Sierra Nevada/Space
    - A spaceplane being a more difficult engineering challenge than a capsule
B: NASA awarded Boeing more money than they did Sierra Nevada
C: NASA awarded significant funding to Boeing years before doing so with Sierra Nevada

All things considered, I think there's lots of reasons to think they'd be more done by now than Boeing is.
I must be reading this wrong. In A you say Boeing has more money and a spaceplane is more difficult, B that NASA gave more money to Boeing, and C NASA gave more more money to Boeing years before SNC.

But your conclusion is that SNC should be further along? Don't you mean Boeing should be further along?
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: darkenfast on 06/03/2023 12:35 am
I've yet to see an explanation for how a crewed DC can abort from inside the fairing. The spacecraft is inside there for a reason.

Crewed version wouldn't be inside a fairing, the last time I asked.

Then why do they need to put the cargo version inside a fairing, and what would change that would make the crewed version work without a fairing?
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Lee Jay on 06/03/2023 12:49 am
I've yet to see an explanation for how a crewed DC can abort from inside the fairing. The spacecraft is inside there for a reason.

Crewed version wouldn't be inside a fairing, the last time I asked.

Then why do they need to put the cargo version inside a fairing, and what would change that would make the crewed version work without a fairing?

The cargo version has the aft unpressurized cargo bay and folding wings while the crew version has locked wings.  There are a great many other differences, including propulsion.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Vahe231991 on 06/03/2023 03:03 am
DreamChaser has struggled just as much as Starliner and the bar for unscrewed flight is much lower than for a manned capsule.  There’s zero reason to think they’d be done by now any more than Boeing (although at least they would have been a lot cheaper).

A: Dreamchaser has developed about as fast as Starliner has, despite:
    - Boeing having more internal capital and resources than Sierra Nevada/Space
    - A spaceplane being a more difficult engineering challenge than a capsule
B: NASA awarded Boeing more money than they did Sierra Nevada
C: NASA awarded significant funding to Boeing years before doing so with Sierra Nevada

All things considered, I think there's lots of reasons to think they'd be more done by now than Boeing is.
I must be reading this wrong. In A you say Boeing has more money and a spaceplane is more difficult, B that NASA gave more money to Boeing, and C NASA gave more more money to Boeing years before SNC.

But your conclusion is that SNC should be further along? Don't you mean Boeing should be further along?
The CST-100 Starliner was conceived in 2010. The Dream Chaser's origins go back to 2004, and a 2012 PowerPoint document by Giuseppe De Chiara (see attached file) explains the early genesis of the Dream Chaser as follows:
Quote
The HL-20 story was no to end since in mid 2004 Jim Benson announced that the HL-20 development would be continued by his SpaceDev as Dream Chaser spacecraft. The SpaceDev was acquired by Sierra Nevada Corporation at the very end of 2008. On 1 February 2010, Sierra Nevada Corporation was awarded $20 million under NASA’s Commercial Crew Development (CCDev) phase 1 program for the development of the Dream Chaser. On 3 August 2012, NASA announced the award of $212.5 million to Sierra Nevada to continue work on the Dream Chaser under the Commercial Crew Integrated Capability (CCiCAP) Program. Even if it share the same shape of HL-20, the Dream Chaser is a quite different vehicle inside using a lot of “state of the art technologies” (as carbon fiber for the pressure vessel and other structural elements).

In other words, SpaceDev decided to take over design and development of the HL-20 in mid-2004, using the HL-20 airframe as the basis for the new Dream Chaser, and development of the Dream Chaser continued despite the Sierra Nevada Corporation acquired SpaceDev in late 2008. Even if Dream Chaser has yet to make an orbital flight, the gestation of development and testing of the Dream Chaser spaceplane is more comparable to that of the X-37 (which was initially designed for launch from the Space Shuttle's cargo bay but was later reworked for launches from the Atlas V in the early 2000s) than to development of the Starliner.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: darkenfast on 06/03/2023 08:04 am
I've yet to see an explanation for how a crewed DC can abort from inside the fairing. The spacecraft is inside there for a reason.

Crewed version wouldn't be inside a fairing, the last time I asked.

Then why do they need to put the cargo version inside a fairing, and what would change that would make the crewed version work without a fairing?

The cargo version has the aft unpressurized cargo bay and folding wings while the crew version has locked wings.  There are a great many other differences, including propulsion.

My point is that Dream Chaser without the fairing represents an aerodynamic challenge for the launch vehicle. This would take time and money to solve. It appears to have been enough of a problem to make the weight and expense of the folding wing mechanism and the weight and expense of the fairing worth it for the cargo version, which does not need an abort system. If it was just the cargo module that was the problem, a much smaller set of panels, such as those covering Orion's service module would have sufficed.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Star One on 06/03/2023 10:28 am
DreamChaser has struggled just as much as Starliner and the bar for unscrewed flight is much lower than for a manned capsule.  There’s zero reason to think they’d be done by now any more than Boeing (although at least they would have been a lot cheaper).

A: Dreamchaser has developed about as fast as Starliner has, despite:
    - Boeing having more internal capital and resources than Sierra Nevada/Space
    - A spaceplane being a more difficult engineering challenge than a capsule
B: NASA awarded Boeing more money than they did Sierra Nevada
C: NASA awarded significant funding to Boeing years before doing so with Sierra Nevada

All things considered, I think there's lots of reasons to think they'd be more done by now than Boeing is.
Sierra Nevada strike me as a more agile company than Boeing these days, and one I’d have more faith in delivering a product on time.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: vt_hokie on 06/03/2023 05:32 pm
I think it's questionable whether or not crew Dream Chaser would have had a smoother development path than Starliner.  What I do believe is that it would have been a better long term investment with more potential beyond the initial commercial crew missions, and that Starliner has a much higher probability of being a dead end.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: mandrewa on 06/03/2023 05:52 pm
Here's a comparison of the different options for carrying cargo to orbit. Like several other people in this thread I searched for Dream Chaser's payload volume and was unable to find it.

This list is restricted to the democracies.  I believe this is all of the space cargo vessels that either exist or are actually being built.


Cargo Dragon V2
---------------
6.4 mt dry mass
6.0 mt up mass
2.5 mt down mass
 9.3 m^3 pressurized volume
12.1 m^3 unpressurized volume (standard trunk)
37.0 m^3 unpressurized volume (extended trunk)
maximum 10 day free flight
maximum 9 month docked to supporting station
reused


Cygnus, enhanced version
------------------------
3.4 mt dry mass
3.8 mt up mass (footnote 1)
27.0 m^3 pressurized volume
27.0 m^3 disposal volume
expended


Cargo Dream Chaser
------------------
NET 2023
(Dream Chaser lander + Shooting Stars module)
5.0 mt pressurized up mass
0.5 mt unpressurized up mass
1.75 mt pressurized down mass (with maximum 1.5 G force rentry)
3.25 mt disposal mass
lander is reused, module is expended


Cargo Starship
--------------
NET 2024
~ 120 mt dry mass
~ 150 mt pressurized up mass
reused


HTV-X
-----------
NET 2024
8.3 mt dry mass
4.07 mt pressurized up mass
1.75 mt unpressurized up mass
78 m^3 pressurized volume
maximum 6 months docked to supporting station
maximum 1.5 years free flight
expended

Footnote 1: The Cygnus up mass limit will depend on the rocket launching it.  3.8 mt is the largest payload mass launched so far.  But Northrup-Grumman claims 3.5 metric tons is the limit. That may be based on the Antares rocket.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: JAFO on 06/03/2023 07:19 pm
blah blah blah...

You seem to think that the ability to copy and post things you find on the internet makes you a valued member and "authoritative expert" on this forum, but the truth is far from that. I have no interest in debating you but to update people new to her, Dream Chaser actually traces her heritage back to the Soviet BOR-4 program and even the NASA light/heavyweight lifting bodies.

(One could also make a good argument that the Boeing Starliner traces its heritage all the way back to Max Faget’s first capsule and it has just been building on 1950s era research and development. Starliner has often been called Apollo on steroids, giving even less excuse for Boeing's repeated delays.)


https://www.youtube.com/watch?v=LK0XZjQf7AM&ab_channel=ScottManley (https://www.youtube.com/watch?v=LK0XZjQf7AM&ab_channel=ScottManley)
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Lee Jay on 06/03/2023 07:26 pm
My point is that Dream Chaser without the fairing represents an aerodynamic challenge for the launch vehicle. This would take time and money to solve. It appears to have been enough of a problem to make the weight and expense of the folding wing mechanism and the weight and expense of the fairing worth it for the cargo version, which does not need an abort system.

If you have any evidence that that is the reason, I'd like to see it.  I was told the exact opposite directly by them - that the fairing is a far larger aerodynamic problem for the LV than DC would be in free-stream.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: JEF_300 on 06/03/2023 07:27 pm
DreamChaser has struggled just as much as Starliner and the bar for unscrewed flight is much lower than for a manned capsule.  There’s zero reason to think they’d be done by now any more than Boeing (although at least they would have been a lot cheaper).

A: Dreamchaser has developed about as fast as Starliner has, despite:
    - Boeing having more internal capital and resources than Sierra Nevada/Space
    - A spaceplane being a more difficult engineering challenge than a capsule
B: NASA awarded Boeing more money than they did Sierra Nevada
C: NASA awarded significant funding to Boeing years before doing so with Sierra Nevada

All things considered, I think there's lots of reasons to think they'd be more done by now than Boeing is.
I must be reading this wrong. In A you say Boeing has more money and a spaceplane is more difficult, B that NASA gave more money to Boeing, and C NASA gave more more money to Boeing years before SNC.

But your conclusion is that SNC should be further along? Don't you mean Boeing should be further along?

I guess you were reading it wrong. My conclusion is that SNC would be further along had they had the support Boeing has.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: JAFO on 06/03/2023 07:30 pm
DreamChaser has struggled just as much as Starliner and the bar for unscrewed flight is much lower than for a manned capsule.  There’s zero reason to think they’d be done by now any more than Boeing (although at least they would have been a lot cheaper).

A: Dreamchaser has developed about as fast as Starliner has, despite:
    - Boeing having more internal capital and resources than Sierra Nevada/Space
    - A spaceplane being a more difficult engineering challenge than a capsule
B: NASA awarded Boeing more money than they did Sierra Nevada
C: NASA awarded significant funding to Boeing years before doing so with Sierra Nevada

All things considered, I think there's lots of reasons to think they'd be more done by now than Boeing is.
I must be reading this wrong. In A you say Boeing has more money and a spaceplane is more difficult, B that NASA gave more money to Boeing, and C NASA gave more more money to Boeing years before SNC.

But your conclusion is that SNC should be further along? Don't you mean Boeing should be further along?

I guess you were reading it wrong. My conclusion is that SNC would be further along had they had the support Boeing has.

My apologies, and I agree.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: JEF_300 on 06/03/2023 07:35 pm
My point is that Dream Chaser without the fairing represents an aerodynamic challenge for the launch vehicle. This would take time and money to solve. It appears to have been enough of a problem to make the weight and expense of the folding wing mechanism and the weight and expense of the fairing worth it for the cargo version, which does not need an abort system.

If you have any evidence that that is the reason, I'd like to see it.  I was told the exact opposite directly by them - that the fairing is a far larger aerodynamic problem for the LV than DC would be in free-stream.

Which makes sense if you think about it. Sure, a Dreamchaser in the open will cause some lift-forces on weird vectors, but that's not going to be anything that a tiny bit of gimballing from the main engines won't totally counteract. The fairing, meanwhile, massively increases the forward area of the vehicle, and thus increases the aerodynamic losses experienced on ascent (assuming we're talking about Atlas).

We've got to remember that these are real rockets being flown by computers, not rockets in KSP being flown by hand. If modern guidance software can manage the Astra slide, then I don't see any reason to believe it couldn't handle Dreamchaser.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Jim on 06/03/2023 07:43 pm
My point is that Dream Chaser without the fairing represents an aerodynamic challenge for the launch vehicle. This would take time and money to solve. It appears to have been enough of a problem to make the weight and expense of the folding wing mechanism and the weight and expense of the fairing worth it for the cargo version, which does not need an abort system.

If you have any evidence that that is the reason, I'd like to see it.  I was told the exact opposite directly by them - that the fairing is a far larger aerodynamic problem for the LV than DC would be in free-stream.

Wrong.   Unsymmetrical load would be more of a problem.   Vulcan isn't a hammerhead like the Atlas V 5XX.  Vulcan has a similar fairing/adapter system like Delta IV.  Removing fairing now puts aeroloads directly on the adapter cone and the spacecraft  asymmetrical loads.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: mandrewa on 06/03/2023 07:44 pm
My point is that Dream Chaser without the fairing represents an aerodynamic challenge for the launch vehicle. This would take time and money to solve. It appears to have been enough of a problem to make the weight and expense of the folding wing mechanism and the weight and expense of the fairing worth it for the cargo version, which does not need an abort system.

If you have any evidence that that is the reason, I'd like to see it.  I was told the exact opposite directly by them - that the fairing is a far larger aerodynamic problem for the LV than DC would be in free-stream.

If the fairing is a larger aerodynamic problem, why in the world are they launching it in a fairing?
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: JEF_300 on 06/03/2023 07:52 pm
If the fairing is a larger aerodynamic problem, why in the world are they launching it in a fairing?

Because extending solar panels don't do well at a high airspeed perhaps?
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: mandrewa on 06/03/2023 08:10 pm
If the fairing is a larger aerodynamic problem, why in the world are they launching it in a fairing?

Because extending solar panels don't do well at a high airspeed perhaps?

That's a good answer.  And of course they need the Shooting Star to bring the payload mass and volume up to reasonable numbers.

But that raises another possibility.  The volume of the DC-201, or Crew Dream Chaser, is 40% larger than the current Cargo Dream Chaser. Or at least I assume Sierra Space was talking about volume when they said the DC-201 was 40% larger.  I wonder if they did a cargo version of the DC-201 if they might not end up with a vehicle that has a larger payload volume than the current Dream Chaser plus Shooting Star combination.

And in that case, this might eliminate the need for Shooting Star, and it would also mean there was more commonality between the this future Cargo Dream Chaser and the future Crew Dream Chaser.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Lee Jay on 06/03/2023 09:06 pm
My point is that Dream Chaser without the fairing represents an aerodynamic challenge for the launch vehicle. This would take time and money to solve. It appears to have been enough of a problem to make the weight and expense of the folding wing mechanism and the weight and expense of the fairing worth it for the cargo version, which does not need an abort system.

If you have any evidence that that is the reason, I'd like to see it.  I was told the exact opposite directly by them - that the fairing is a far larger aerodynamic problem for the LV than DC would be in free-stream.

Wrong.   Unsymmetrical load would be more of a problem.   Vulcan isn't a hammerhead like the Atlas V 5XX.  Vulcan has a similar fairing/adapter system like Delta IV.  Removing fairing now puts aeroloads directly on the adapter cone and the spacecraft  asymmetrical loads.

Well, Steve Lindsey told me that in person.  He said the aero loads from the fairing were massively higher than from an exposed vehicle.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Steven Pietrobon on 06/04/2023 06:53 am
..., Dream Chaser actually traces her heritage back to the Soviet BOR-4 program and even the NASA light/heavyweight lifting bodies.

It actually goes back to the USAF PRIME re-entry test vehicle from 1966!

https://space.skyrocket.de/doc_sdat/prime.htm
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Alpha Control on 06/08/2023 01:55 am
..., Dream Chaser actually traces her heritage back to the Soviet BOR-4 program and even the NASA light/heavyweight lifting bodies.

It actually goes back to the USAF PRIME re-entry test vehicle from 1966!

https://space.skyrocket.de/doc_sdat/prime.htm

Thanks for posting that, Steven. I wasn't aware of the X-23 program. Did this feed into the Space Shuttle design at all?
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Steven Pietrobon on 06/08/2023 06:39 am
Thanks for posting that, Steven. I wasn't aware of the X-23 program. Did this feed into the Space Shuttle design at all?

I don't know, but I would have not been surprised if NASA used the data from PRIME (and the previous ASSET) flights to help model Space Shuttle re-entry.

https://space.skyrocket.de/doc_sdat/asset-aev.htm
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: shintoo on 06/28/2023 03:30 pm
From the Spacenews article (https://spacenews.com/sierra-space-describes-long-term-plans-for-dream-chaser-and-inflatable-modules/ (https://spacenews.com/sierra-space-describes-long-term-plans-for-dream-chaser-and-inflatable-modules/)):

Quote
Vice hinted that the company has longer-term plans for Dream Chaser that could possibly allow it to end dependence on other companies’ launch vehicles. “We’re thinking about investigating the right technologies in thermal and propulsion and materials that allows us to potentially think about the staging options that would allow us, for the first time, have horizontal takeoff,” he said. He didn’t offer a schedule for developing that version of Dream Chaser.

(Emphasis mine.)

This is so very far out into the future, considering we haven't seen even the first launch yet, but it is interesting to consider what they could be referring to here. Dropping from a mothership plane (Roc, Cosmic Girl-esque) perhaps? A 747 like Cosmic Girl would definitely not have the capacity to airlaunch something like Dream Chaser, and I doubt the Roc could either, with a booster sizeable enough to get a massive DC to orbit. So they must be thinking about something entirely new.

Far, far off into the future for sure. :)
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: adrianwyard on 06/28/2023 03:45 pm
In the article Tom Vice says "We just think [Dream Chaser] is the way people are going to want to fly back and land.” By context this appears to be referring to the next version and he did not say *launch* and land. If that was intentional I wonder if this means there will still not be an abort capability.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: butters on 06/28/2023 03:48 pm
A 330 cubic meter inflatable module. Deja vu!

In fairness, Sierra has a significant advantage over the prior efforts by Bigelow purely because of launch vehicle options. They're not limited to Atlas V 551, which presented a prohibitive challenge with electrical power for a module of that size. They can go heavier with Vulcan, or New Glenn if they need more fairing volume for packaging the solar arrays.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: JEF_300 on 06/28/2023 07:30 pm
From the Spacenews article (https://spacenews.com/sierra-space-describes-long-term-plans-for-dream-chaser-and-inflatable-modules/ (https://spacenews.com/sierra-space-describes-long-term-plans-for-dream-chaser-and-inflatable-modules/)):

Quote
Vice hinted that the company has longer-term plans for Dream Chaser that could possibly allow it to end dependence on other companies’ launch vehicles. “We’re thinking about investigating the right technologies in thermal and propulsion and materials that allows us to potentially think about the staging options that would allow us, for the first time, have horizontal takeoff,” he said. He didn’t offer a schedule for developing that version of Dream Chaser.

(Emphasis mine.)

This is so very far out into the future, considering we haven't seen even the first launch yet, but it is interesting to consider what they could be referring to here. Dropping from a mothership plane (Roc, Cosmic Girl-esque) perhaps? A 747 like Cosmic Girl would definitely not have the capacity to airlaunch something like Dream Chaser, and I doubt the Roc could either, with a booster sizeable enough to get a massive DC to orbit. So they must be thinking about something entirely new.

Far, far off into the future for sure. :)

Well, I'm not so sure. In the past there have been quite a lot of, admittedly rather out of date, renders of a Dreamchaser being launched off Roc. At the very least they at one point thought it was possible.

Here's a NASASpaceflight article about Dreamchaser on Roc from 2014:
https://www.nasaspaceflight.com/2014/10/dream-chaser-eyes-rides-with-under-review-stratolaunch-system/
Image bellow is the render from that time:
(https://cdn.mos.cms.futurecdn.net/avgM947Dy3FZYSnEk6SDQL.jpg)

I suspect that if you go with an all hydrolox launcher design, it might just barely be possible to build rocket that can launch Dreamchaser from Roc. It would certainly explain Stratolaunch's design decisions back when they were working on the PGA engine; it was a fuel-rich staged combustion hydrolox booster engine, about the size of Merlin 1D. Perfect for making your launch vehicle as light, when fueled, as can be managed. Please note that this is all purely vibes/it's-what-make-sense-to-me based. I haven't actually sat down and done the math for it.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: whitelancer64 on 06/28/2023 08:46 pm
From the Spacenews article (https://spacenews.com/sierra-space-describes-long-term-plans-for-dream-chaser-and-inflatable-modules/ (https://spacenews.com/sierra-space-describes-long-term-plans-for-dream-chaser-and-inflatable-modules/)):

Quote
Vice hinted that the company has longer-term plans for Dream Chaser that could possibly allow it to end dependence on other companies’ launch vehicles. “We’re thinking about investigating the right technologies in thermal and propulsion and materials that allows us to potentially think about the staging options that would allow us, for the first time, have horizontal takeoff,” he said. He didn’t offer a schedule for developing that version of Dream Chaser.

(Emphasis mine.)

This is so very far out into the future, considering we haven't seen even the first launch yet, but it is interesting to consider what they could be referring to here. Dropping from a mothership plane (Roc, Cosmic Girl-esque) perhaps? A 747 like Cosmic Girl would definitely not have the capacity to airlaunch something like Dream Chaser, and I doubt the Roc could either, with a booster sizeable enough to get a massive DC to orbit. So they must be thinking about something entirely new.

Far, far off into the future for sure. :)

Well, I'm not so sure. In the past there have been quite a lot of, admittedly rather out of date, renders of a Dreamchaser being launched off Roc. At the very least they at one point thought it was possible.

Here's a NASASpaceflight article about Dreamchaser on Roc from 2014:
https://www.nasaspaceflight.com/2014/10/dream-chaser-eyes-rides-with-under-review-stratolaunch-system/
Image bellow is the render from that time:
(https://cdn.mos.cms.futurecdn.net/avgM947Dy3FZYSnEk6SDQL.jpg)

I suspect that if you go with an all hydrolox launcher design, it might just barely be possible to build rocket that can launch Dreamchaser from Roc. It would certainly explain Stratolaunch's design decisions back when they were working on the PGA engine; it was a fuel-rich staged combustion hydrolox booster engine, about the size of Merlin 1D. Perfect for making your launch vehicle as light, when fueled, as can be managed. Please note that this is all purely vibes/it's-what-make-sense-to-me based. I haven't actually sat down and done the math for it.

Note the rocket shown was called the Pegasus II, in development by Orbital (prior to their merger with ATK) in partnership with Stratolaunch. It was a 3 stage rocket, the first two stages were solid rocket motors, and the third stage was hydrolox, powered by one or two RL-10 engines. It had a payload capacity of 13,500 lb (6.1 metric tons) to LEO.

The DreamChaser to be launched was a 75% scale variant designed to be capable of flying 3 passengers or cargo.

Additional info: the Pegasus II solid rocket motors were the same diameter as the Shuttle SRB but had a carbon composite casing and a more energetic propellant mix. The first stage (which had two short wings and a V tail) was intended to be recoveable after splashdown.

The design was modified in late 2014 to use all solid rocket motors. However, the economic / business case for it never closed, so development was shelved, and later abandoned altogether.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: shintoo on 06/29/2023 03:05 pm
<snip />
Well, I'm not so sure. In the past there have been quite a lot of, admittedly rather out of date, renders of a Dreamchaser being launched off Roc. At the very least they at one point thought it was possible.

Here's a NASASpaceflight article about Dreamchaser on Roc from 2014:
https://www.nasaspaceflight.com/2014/10/dream-chaser-eyes-rides-with-under-review-stratolaunch-system/
Image bellow is the render from that time:
<snip />

I suspect that if you go with an all hydrolox launcher design, it might just barely be possible to build rocket that can launch Dreamchaser from Roc. It would certainly explain Stratolaunch's design decisions back when they were working on the PGA engine; it was a fuel-rich staged combustion hydrolox booster engine, about the size of Merlin 1D. Perfect for making your launch vehicle as light, when fueled, as can be managed. Please note that this is all purely vibes/it's-what-make-sense-to-me based. I haven't actually sat down and done the math for it.

Ah, I forgot about that concept, thanks for bringing it up again. It does, at the very least, show that they have been thinking about it for quite some time. I had assumed in my previous post that what they are currently considering is a horizontal takeoff for the "40% upscaled" (whether that is mass, volume, cargo capacity, I am not sure) crew-capable DC-200. As whitelancer64 pointed out, that version of DC being at 75% scale makes me less than hopeful that the much larger DC-200 could be launched by any sort of booster from underneath Roc. Still, I absolutely love that render.

<snip />
Note the rocket shown was called the Pegasus II, in development by Orbital (prior to their merger with ATK) in partnership with Stratolaunch. It was a 3 stage rocket, the first two stages were solid rocket motors, and the third stage was hydrolox, powered by one or two RL-10 engines. It had a payload capacity of 13,500 lb (6.1 metric tons) to LEO.

The DreamChaser to be launched was a 75% scale variant designed to be capable of flying 3 passengers or cargo.

Additional info: the Pegasus II solid rocket motors were the same diameter as the Shuttle SRB but had a carbon composite casing and a more energetic propellant mix. The first stage (which had two short wings and a V tail) was intended to be recoveable after splashdown.

The design was modified in late 2014 to use all solid rocket motors. However, the economic / business case for it never closed, so development was shelved, and later abandoned altogether.

Cheers for the great info on that project. I wasn't aware it was a scaled down version, that's really interesting. I suppose if DC had to be scaled down to launch under Roc, DC-200 launching under it is completely out of the question. I wonder if they are in discussions with Stratolaunch (or Scaled for a new aircraft?) for this new early-stage project with DC-200, if I'm not just plain wrong that Vice was referring to horizontal takeoff of DC-200. Certainly plenty of kinks to work out.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Lampyridae on 07/02/2023 10:03 am
Sierra Space describes long-term plans for Dream Chaser and inflatable modules:
https://spacenews.com/sierra-space-describes-long-term-plans-for-dream-chaser-and-inflatable-modules/

https://twitter.com/SpaceNews_Inc/status/1674017635472748546

I see they mention horizontal takeoff in the context of ending dependence on third-party launch vehicles...
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: lrk on 07/05/2023 10:41 pm
Sierra Space describes long-term plans for Dream Chaser and inflatable modules:
https://spacenews.com/sierra-space-describes-long-term-plans-for-dream-chaser-and-inflatable-modules/

https://twitter.com/SpaceNews_Inc/status/1674017635472748546

I see they mention horizontal takeoff in the context of ending dependence on third-party launch vehicles...

 :o

Partnership with Stratolaunch?  Stratolaunch seems to be pivoting away from using Roc for Talon missions...
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: mn on 07/06/2023 03:12 am
Sierra Space describes long-term plans for Dream Chaser and inflatable modules:
https://spacenews.com/sierra-space-describes-long-term-plans-for-dream-chaser-and-inflatable-modules/

https://twitter.com/SpaceNews_Inc/status/1674017635472748546

Quote
As Sierra Space continues to prepare for the first flight of its Dream Chaser vehicle, it is outlining long-term ambitions for both that vehicle and space station modules
.

The headline says plans but the article more accurately describes it as ambitions.

Quote
We’re thinking about investigating the right technologies in thermal and propulsion and materials that allows us to potentially think about the staging options that would allow us, for the first time, have horizontal takeoff

My BS meter is way way up on this. I'm thinking of considering to investigate the possibility of believing any of this.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: shintoo on 07/06/2023 05:44 am
Quote
As Sierra Space continues to prepare for the first flight of its Dream Chaser vehicle, it is outlining long-term ambitions for both that vehicle and space station modules
.

The headline says plans but the article more accurately describes it as ambitions.

Quote
We’re thinking about investigating the right technologies in thermal and propulsion and materials that allows us to potentially think about the staging options that would allow us, for the first time, have horizontal takeoff

My BS meter is way way up on this. I'm thinking of considering to investigate the possibility of believing any of this.

Especially when it's an investor conference... wild, oft unrealistic pitches seem to be a trend at those.

Let's root for 'em anyway. ;D
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Nomadd on 07/06/2023 09:21 am
 I thought a loaded Dreamchaser was about twice the mass a Roc could orbit.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: spacebleachers on 07/06/2023 11:12 am
This convo already occurred in another thread, but I can’t remember which one. It was based upon previous Stratolaunch pics. The net result of the discussion was that the spaceplane was somewhere in the neighborhood of 50 - 75% of the current Dream Chaser.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: whitelancer64 on 07/06/2023 04:59 pm
Back in 2014 a 75% scale DreamChaser vehicle was envisioned to fly on Stratolaunch with a three-stage Pegasus II rocket. It would have held cargo or 2-3 people.

Stratolaunch is not likely capable of launching a full sized cargo DreamChaser, nor the larger crew variant planned.

Since neither could realistically fly on Stratolaunch, it stands to reason that this is something different.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: shintoo on 07/12/2023 06:16 pm
https://www.nasa.gov/jsc/procurement/ccsc2

Quote from: Philip R. McAlister
For the Technical Approach evaluation, Sierra Space’s proposed technical approach demonstrated overall competence to achieving the proposed capability. Its capability concept received a significant strength for its integrated LEO transportation, destination, and infrastructure capabilities that utilize DC-200, Pathfinder, and other elements.

Emphasis mine.

What does Pathfinder refer to? Is that the name of the first DC-200 and I somehow missed that? Can't find any other references to the name. ???

Edit: It is certainly not the name of the first DC-200, not sure what to make of it. Emphasis mine.:
Quote from: Philip R. McAlister
For the Technical Approach evaluation, there was one new significant strength for engaging with industry partners for alternative transportation options to service Pathfinder and increase flexibility and availability of access.

Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: BrightLight on 07/12/2023 07:43 pm
https://www.businesswire.com/news/home/20230615828732/en/Sierra-Space-Awarded-Space-Act-Agreement-with-NASA
"This SAA award by NASA provides support to a “pathfinder” space station, which serves as a technology demonstration for key elements of commercial space stations. Such demonstrations are vital steps to ultimately designing objects intended for sustained commercial habitation in orbit. The SAA is set to begin while the systems are in the design and development phases and last for five years – through on-orbit deployment later this decade."

https://www.nasa.gov/jsc/procurement/ccsc2

Quote from: Philip R. McAlister
For the Technical Approach evaluation, Sierra Space’s proposed technical approach demonstrated overall competence to achieving the proposed capability. Its capability concept received a significant strength for its integrated LEO transportation, destination, and infrastructure capabilities that utilize DC-200, Pathfinder, and other elements.

Emphasis mine.

What does Pathfinder refer to? Is that the name of the first DC-200 and I somehow missed that? Can't find any other references to the name. ???

Edit: It is certainly not the name of the first DC-200, not sure what to make of it. Emphasis mine.:
Quote from: Philip R. McAlister
For the Technical Approach evaluation, there was one new significant strength for engaging with industry partners for alternative transportation options to service Pathfinder and increase flexibility and availability of access.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: shintoo on 07/12/2023 08:41 pm
https://www.businesswire.com/news/home/20230615828732/en/Sierra-Space-Awarded-Space-Act-Agreement-with-NASA
"This SAA award by NASA provides support to a “pathfinder” space station, which serves as a technology demonstration for key elements of commercial space stations. Such demonstrations are vital steps to ultimately designing objects intended for sustained commercial habitation in orbit. The SAA is set to begin while the systems are in the design and development phases and last for five years – through on-orbit deployment later this decade."

<snip />

Thanks - I think the capitalization of "Pathfinder" threw me off.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: yg1968 on 07/13/2023 03:33 am
https://www.businesswire.com/news/home/20230615828732/en/Sierra-Space-Awarded-Space-Act-Agreement-with-NASA
"This SAA award by NASA provides support to a “pathfinder” space station, which serves as a technology demonstration for key elements of commercial space stations. Such demonstrations are vital steps to ultimately designing objects intended for sustained commercial habitation in orbit. The SAA is set to begin while the systems are in the design and development phases and last for five years – through on-orbit deployment later this decade."

<snip />

Thanks - I think the capitalization of "Pathfinder" threw me off.

Their space station is called Pathfinder:

Quote from: page 16 of the Source Selection Statement
While discussing Sierra Space’s proposal during the selection meeting, I noted that there are synergies with Orbital Reef, but enough differences that I see value in providing support to the development of Sierra Space’s Pathfinder station and DC-200 crew transportation system.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: FutureSpaceTourist on 07/22/2023 06:59 am
https://www.sierraspace.com/newsroom/blog/dream-chaser-vs-space-shuttle/

Quote
Dream Chaser vs Space Shuttle: A Side-by-Side Comparison
JULY 21, 2023   |   BLOG

When most people think of space travel, they likely think of space shuttles. What they don’t realize is that these were a specific type of reusable spacecraft only used by NASA from 1981 until 2011.

More than a decade ago today, on July 21, 2011, the last space shuttle mission landed at the legendary facility in the heart of Florida’s “Space Coast.” As Atlantis landed for the final time so too concluded the chapter in NASA’s 30-year shuttle program.

The historic runway at Kennedy Space Center has remained largely quiet since – for too long – as humanity lost the ability to return from space with a low-G runway landing and we bid farewell to an icon of spaceflight.

But that’s about to change.

Sierra Space is dedicated to bringing the Kennedy Space Center runway back to life and ushering in the next era of space exploration with its revolutionary fleet of Dream Chaser® spaceplanes.

The Dream Chaser is the first-ever winged commercial spaceplane, and although it looks somewhat like NASA’s space shuttle, it’s something entirely new. It’s also unlike Boeing’s X-37b, which exclusively conducts military missions, in that it will open shared access to space and international collaboration for all humankind

So, how does a Dream Chaser spaceplane vary from the traditional space shuttles we’re familiar with? Let’s explore the big differences.

Design and Configuration

NASA’s original space shuttle had a wing design much like an airplane. Instead of being independent and perched atop a rocket, it was integrated with an external fuel tank that provided fuel for its main engines and had two solid rocket boosters attached at the sides. Each space shuttle was designed to fly at least 100 missions – but they actually flew fewer than that.

The first model of the DC-100 cargo variant Dream Chaser is named Tenacity. Tenacity represents an uncrewed spiritual successor to the space shuttle, and at 30 feet (9 meters) long, it’s roughly a quarter of the total length of the space shuttle orbiters – though the habitable volume is about half the space shuttle.

The shuttle was 67 cubic meters (not including the airlock), and Tenacity’s pressurized volume is 33 cubic meters (including both the spaceplane and the cargo module). This makes the spaceplane more sustainable and easier to maneuver, but it also assists with gentle 1 g runway landings – ideal for fragile cargo.

Dream Chaser, Tenacity, was originally designed as a crewed spaceplane, partially under NASA’s Commercial Crew Program, before being awarded a NASA Commercial Resupply Services 2 contract. Under this contract, the Dream Chaser spaceplane fleet (including Tenacity), will provide a minimum of seven uncrewed cargo service missions to and from the International Space Station (ISS) and will be designed with high reusability in mind.

Launch and Reentry Procedures

Launching

Sierra Space Dream Chaser LaunchSpace shuttles were launched vertically on a launch pad, utilizing solid rocket boosters (SRBs) and main engines. Thus, shuttles needed 7.8 million pounds of thrust to reach orbit. The SRBs collectively provided 6.6 million pounds of thrust on top of the main shuttle engines, which added a total of 1.2 million pounds of thrust. The SRBs were jettisoned just after two minutes into the flight and the main engine cutoff would happen around eight minutes into the flight.

In comparison, Tenacity is compatible with a wide variety of launch vehicles (rockets) and will be launched in a stowed configuration inside a payload fairing. This makes Tenacity significantly more flexible and reduces ascent loads on the vehicle compared to the space shuttle.

With Tenacity in a payload fairing, it will sit on top of the rocket which will help protect the vehicle from debris. Sierra Space’s DC-200 crewed spaceplane variant will be launched in a similar configuration but without a fairing, which will still offer protection from debris since the rocket will be located below the vehicle.

Reentry

Back in the day, space shuttles executed controlled reentries into Earth’s atmosphere, entering nose-first at a high angle of attack to generate aerodynamic lift. Apollo astronauts were subjected to forces between 3-7 g’s though the shuttle missions saw less than 2 g’s on reentry.

As mentioned earlier, the Tenacity can return critical cargo to Earth at less than 1 g, contributing to a gentle and safe landing for the craft and its potential crew.

Of course, great leaps in tech don’t always happen smoothly. The Tenacity conquered tremendous challenges in its development, including early flight failures. Another big issue was figuring out how to demonstrate the spaceplane’s unique lifting body design ability to return to Earth with a smooth, low-G re-entry.

In 2017, Sierra Space conducted a pivotal test flight. NASA and other stakeholders needed to see that these capabilities were possible outside of computer simulations – so the Sierra Space team tested the hardware during a real, autonomously conducted atmospheric flight.

During the test, the spaceplane entered a 70-degree dive, quickly gaining airspeed to intercept its flight path for a normal Earth return. It performed flawlessly, autonomously deploying its landing gear, flaring, and touching down safely on a runway.
 
Payload and Capacity

Space shuttles had large payload bays that could carry a variety of cargo, including military and defense satellites, scientific instruments, and even entire space station modules. These payloads weighed up to 27,500 kilograms (60,600 pounds) in low-Earth orbit missions.

With the help of Sierra Space’s Shooting Star™ service module, the Tenacity spaceplane can deliver 5,500 kilograms (up to 12,000 pounds) of pressurized and unpressurized cargo to the space station before returning to Earth. Thanks to its internally developed thrusters with three different thrust modes, it can nimbly maneuver in space and ensure deliveries are effectively completed.

Although this payload is smaller, the spaceplane is highly customizable for a range of applications. The Tenacity is a multi-mission vehicle that can provide faster turnarounds and handle more lifetime loads.

Three separate NASA astronaut crews have visited the Sierra Space facilities to train on loading and unloading cargo in anticipation of Dream Chaser deliveries to the ISS.

The Future of Dream Chaser

The Dream Chaser fleet is multi-mission, capable of supporting a variety of low-Earth orbit needs and promising greater efficiencies with high reusability and fast turnaround times. Its customizability makes it ideal for domestic and international customers, as does its flexibility regarding launch site, space destination, mission duration, and landing site.

Tenacity will soon make its maiden voyage to deliver cargo to the ISS as part of its NASA CRS-2 contract. When it does, it will mark the beginning of a new era for space exploration globally (and beyond).

Learn more about Sierra Space and consider joining the team bringing about the Orbital Age TM.

Image captions:

Quote
Illustration of Sierra Space's Dream Chaser spaceplane on reentry

Quote
Sierra Space's Dream Chaser spaceplane landing on runway

Quote
Illustration of Sierra Space's Dream Chaser spaceplane cargo
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Robert_the_Doll on 07/25/2023 07:58 am
https://twitter.com/SierraSpaceCo/status/1683564642122235904

Quote
Before avionics were installed, the internal structure of Dream Chaser had visible gold composite of aluminum foil and other materials. This is used as a leakage liner to prevent oxygen from leaking out of the vehicle and maintain optimal pressure in the cabin.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: yg1968 on 07/29/2023 08:25 pm
Dream Chaser's Russian cousin:

https://www.youtube.com/watch?v=ZrNpSFEFLt0
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: TrevorMonty on 07/30/2023 10:21 pm
Dream Chaser's Russian cousin:

https://www.youtube.com/watch?v=ZrNpSFEFLt0

More like anscestor. DC can trace its heritage to this vehicle via NASA attempts to copy it.

Russians would've been better off making BOR into small manned spaceplane than trying to copy NASA's Shuttle. Being able to land at runway is lot better than trying retrieve Soyzu from wilderness in Russian winter.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Steven Pietrobon on 08/02/2023 08:26 am
More like ancestor. DC can trace its heritage to this vehicle via NASA attempts to copy it.

Russians would've been better off making BOR into small manned spaceplane than trying to copy NASA's Shuttle. Being able to land at runway is lot better than trying retrieve Soyuz from wilderness in Russian winter.

The true ancestor of Dreamchaser is the SV-5D PRIME lifting body, launched from 1966 to 1967 by the USAF! BOR is just a copy of PRIME.

https://space.skyrocket.de/doc_sdat/prime.htm
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: TrevorMonty on 08/02/2023 11:39 am
All stuff I read had BOR first, nice to know USA had idea first.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: adrianwyard on 09/03/2023 01:10 am
Plenty of new info on crewed DC-200 in CCSC2 doc here:

https://www.nasa.gov/saa/domestic/38917_Sierra_Space_CCSC2_SAA-UA-23-38917_Baseline_signed.pdf

Notably: in-flight abort test in early 2026, so ~2.5 years from now. Pretty aggressive.

I'd really like to know why they chose to do a clean sheet design for the crewed vehicle rather than iterate. Perhaps adding comprehensive abort capabilities to current Dream Chaser required so many changes that clean-sheet was the easier path. But that's just a guess.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: JAFO on 09/03/2023 06:07 pm
All stuff I read had BOR first, nice to know USA had idea first.
You need to read this, then. From the original test pilot of the NASA lifting bodies (and X-15 pilot!), Milt Thompson. His X-15 book, At the Edge of Space, is also a fantastic read.


https://www.amazon.com/Flying-Without-Wings-Milton-Thompson/dp/0947554785
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: adrianwyard on 09/07/2023 05:10 pm
Interesting that this new animation depicts white thermal blankets on the leeward side rather than the tiles we see on the actual vehicle. I wonder if they considered blankets earlier then rejected them or if this was just artistic license.

https://www.youtube.com/watch?v=0N95lFqSQvU
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: whitelancer64 on 09/07/2023 05:48 pm
Interesting that this new animation depicts white thermal blankets on the leeward side rather than the tiles we see on the actual vehicle. I wonder if they considered blankets earlier then rejected them or if this was just artistic license.

*snip youtube video*

I don't think those are blankets, the tiles are put on in panels, as seen in the picture here: https://forum.nasaspaceflight.com/index.php?topic=29416.msg2520006#msg2520006

Each panel section does have a tiled texture, it's just not clearly seen until the close up on the "Tenacity" at about 2:00 minute mark.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: adrianwyard on 09/07/2023 06:08 pm
Yeah, too small to be blankets. I bet the animator just found a texture bitmap for shuttle blankets and used it for the white tiles. Actual tiles are pretty smooth:


Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: abaddon on 09/07/2023 06:35 pm
Quote
Sierra Space is dedicated to ushering in the next era of space exploration with its revolutionary fleet of Dream Chaser spaceplanes.

Under the #NASA CRS2 contract, the fleet (including Tenacity) will provide a minimum of seven uncrewed cargo service missions to and from the ISS.
I have a vague memory that Sierra Space committed to build one space plane for the CRS2 contract, but I can't find a reference now, so the "fleet" reference has me wondering if that was true and if anything has changed since then.  Anyone have any information on how many spaceplanes SS is required to build contractually, or information on any other spaceplanes they are actively building?  (Apologies in advance if I missed that information in the thread previously, I don't recall seeing anything about it and didn't find anything with a quick scan).
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: JAFO on 09/07/2023 07:45 pm
Quote
Sierra Space is dedicated to ushering in the next era of space exploration with its revolutionary fleet of Dream Chaser spaceplanes.

Under the #NASA CRS2 contract, the fleet (including Tenacity) will provide a minimum of seven uncrewed cargo service missions to and from the ISS.
I have a vague memory that Sierra Space committed to build one space plane for the CRS2 contract, but I can't find a reference now, so the "fleet" reference has me wondering if that was true and if anything has changed since then.  Anyone have any information on how many spaceplanes SS is required to build contractually, or information on any other spaceplanes they are actively building?  (Apologies in advance if I missed that information in the thread previously, I don't recall seeing anything about it and didn't find anything with a quick scan).

And then there were two...[/font][/size]
Aug 30, 2022

https://twitter.com/SierraSpaceCo/status/1564649662958772229?ref_src=twsrc%5Etfw%7Ctwcamp%5Etweetembed%7Ctwterm%5E1564649662958772229%7Ctwgr%5Eff5c784f0cd993bb5f4f817b3ce85f6e8696d0b0%7Ctwcon%5Es1_&ref_url=https%3A%2F%2Fforum.nasaspaceflight.com%2Findex.php%3Faction%3Dprofileu%3D14344area%3Dshowpostsstart%3D80 (https://twitter.com/SierraSpaceCo/status/1564649662958772229?ref_src=twsrc%5Etfw%7Ctwcamp%5Etweetembed%7Ctwterm%5E1564649662958772229%7Ctwgr%5Eff5c784f0cd993bb5f4f817b3ce85f6e8696d0b0%7Ctwcon%5Es1_&ref_url=https%3A%2F%2Fforum.nasaspaceflight.com%2Findex.php%3Faction%3Dprofileu%3D14344area%3Dshowpostsstart%3D80)
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Kiwi53 on 09/22/2023 05:44 am
Quote from: Chris Bergin tweet
Each tile is unique in design, and differ in size, shape, thickness, and density. They plan to re-waterproof between missions similar to Shuttle.

Oh dear.
That doesn't seem at all like a formula for rapid reuse, but maybe that's not a Sierra Space design goal?
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Asteroza on 09/22/2023 06:54 am
Quote from: Chris Bergin tweet
Each tile is unique in design, and differ in size, shape, thickness, and density. They plan to re-waterproof between missions similar to Shuttle.
Oh dear.
That doesn't seem at all like a formula for rapid reuse, but maybe that's not a Sierra Space design goal?

Rapid reuse is not likely a goal if they are exclusively riding on Vulcan. There will be plenty of time to do maintenance between launch opportunities for the foreseeable future.

Now, if they were riding on SpaceX, then yes, they would have to step up their game. But, the physical size of the vehicle make automating the rewaterproofing step much easier, compared to needing a gigantic OPF bay and workforce like the shuttle. Tile replacement depends on their inventory plan though. For example, having a full set of tile molds ready, but only baking tiles when needed, based on the speed of SpaceX's tile hatchery, suggests that might be a viable approach over having a full set of tiles in storage. If the molds themselves are rapidly 3D printable then that avoids mold storage as well at the cost of mold print time.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Lee Jay on 09/23/2023 01:47 am
Quote from: Chris Bergin tweet
Each tile is unique in design, and differ in size, shape, thickness, and density. They plan to re-waterproof between missions similar to Shuttle.

Oh dear.
That doesn't seem at all like a formula for rapid reuse, but maybe that's not a Sierra Space design goal?

You have to realize that DC is dramatically smaller than Shuttle and that it's not in a debris field on the side of a launcher.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: JAFO on 09/23/2023 04:01 am
Quote from: Chris Bergin tweet
Each tile is unique in design, and differ in size, shape, thickness, and density. They plan to re-waterproof between missions similar to Shuttle.

Oh dear.
That doesn't seem at all like a formula for rapid reuse, but maybe that's not a Sierra Space design goal?
She's also not sitting out on the pad for weeks on end being rained on or beat up by woodpeckers (tic).

Since Dream Chaser will be enclosed in the shroud before rolling out to the pad, I wonder how much waterproofing of the tiles is necessary, or if the waterproofing also does some other function aside from just keeping rain out? Is the humidity at the Cape be that bad that a tile would absorb moisture even in dry weather?

They can't fly an approach in any kind of weather without risking eroding many, many of the tiles so it's not to protect them in an IMC approach. Also, IIRC shuttle desigineers were worried that the damage caused by flying through rain might be enough to seriously impact the L/D of the vehicle and it might not even make the runway.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: litton4 on 10/02/2023 02:17 pm
Doesn't look like they have gap fillers between the tiles - no concerns about structure flexing causing tiles to chip or crack?

https://forum.nasaspaceflight.com/index.php?action=dlattach;topic=29416.0;attach=2218910;image

(https://forum.nasaspaceflight.com/assets/29416.0/2218911.jpg)
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: whitelancer64 on 10/02/2023 02:48 pm
Doesn't look like they have gap fillers between the tiles - no concerns about structure flexing causing tiles to chip or crack?

https://forum.nasaspaceflight.com/index.php?action=dlattach;topic=29416.0;attach=2218910;image

(https://forum.nasaspaceflight.com/assets/29416.0/2218911.jpg)

There are gap fillers, you just can't see them in that photo.

Here's one where you can see some of them:
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: FutureSpaceTourist on 10/12/2023 04:22 pm
https://twitter.com/sierraspaceco/status/1712503437617942696

Quote
To help understand the Dream Chaser® spaceplane’s hypersonic aerodynamics before our ETA test flight in 2017, this 6% stainless steel scale model was tested at speeds up to Mach 14. The test included the use of rudder and wing actuation.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Starmang10 on 10/13/2023 01:17 pm
i dont like how sierra space is taking complete credit for the design, when it was based off of hl-20.  sad that its happening ngl
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: whitelancer64 on 10/17/2023 06:05 pm
i dont like how sierra space is taking complete credit for the design, when it was based off of hl-20.  sad that its happening ngl

HL-20 never got much further than a mockup build and system studies.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: JEF_300 on 10/17/2023 07:48 pm
i dont like how sierra space is taking complete credit for the design, when it was based off of hl-20.  sad that its happening ngl

They aren't. It's not like the HL-20 program is being kept secret or something.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Jim on 10/31/2023 05:44 pm
Quote
First Look: Sierra Space (@SierraSpaceCo) has provided NSF with these unreleased photos of Dream Chaser Tenacity's Thermal Protection System (TPS) tiles, as she continues preparations for her maiden flight to the ISS on ULA's Vulcan rocket.

They plan to re-waterproof between missions similar to Shuttle.


Why is this needed if the vehicle is encapsulated and not exposed to the elements?
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Robert_the_Doll on 10/31/2023 05:49 pm
Quote
First Look: Sierra Space (@SierraSpaceCo) has provided NSF with these unreleased photos of Dream Chaser Tenacity's Thermal Protection System (TPS) tiles, as she continues preparations for her maiden flight to the ISS on ULA's Vulcan rocket.

They plan to re-waterproof between missions similar to Shuttle.


Why is this needed if the vehicle is encapsulated and not exposed to the elements?

Not when it lands at the Shuttle Landing Facility at end of mission, and then has to be towed off back the processing facility several miles away. And that will be even more true when or if it ever lands somewhere else.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Jim on 10/31/2023 06:09 pm

Not when it lands at the Shuttle Landing Facility at end of mission, and then has to be towed off back the processing facility several miles away. And that will be even more true when or if it ever lands somewhere else.


Not going to land if rain is eminent.  The shuttle was out on the pad in the rain.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Robert_the_Doll on 10/31/2023 06:43 pm

Not when it lands at the Shuttle Landing Facility at end of mission, and then has to be towed off back the processing facility several miles away. And that will be even more true when or if it ever lands somewhere else.


Not going to land if rain is eminent.  The shuttle was out on the pad in the rain.

Moisture in the air, and it can rain while Tenacity is being towed off the runway. It is Florida, after all.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: ELinder on 11/02/2023 02:36 pm
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We have arrived at a profound milestone in both our company’s journey and our industry’s future,” said CEO Tom Vice.

Tenacity, the first vehicle in the Dream Chaser fleet is complete, and will ship to NASA’s Neil Armstrong Test Facility in coming weeks.

I'm glad they're getting closer to shipping, but judging by the photos their definition of complete must be pretty loose.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Lee Jay on 11/02/2023 02:38 pm
Quote
We have arrived at a profound milestone in both our company’s journey and our industry’s future,” said CEO Tom Vice.

Tenacity, the first vehicle in the Dream Chaser fleet is complete, and will ship to NASA’s Neil Armstrong Test Facility in coming weeks.

I'm glad they're getting closer to shipping, but judging by the photos their definition of complete must be pretty loose.

Sometimes things need to be partially disassembled for shipping, to get to tie-down points and such.  Maybe the missing bits are for that or a related purpose.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Robert_the_Doll on 11/03/2023 02:38 pm
Some of those "bare" areas on Tenacity appear to just need closeout panels installed, and in others, it will just require some some the thermal tile-covered panels to be placed over the aluminum alloy skin of the airframe.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: edzieba on 11/10/2023 12:56 pm
I don't believe that this image of crewed DC has been posted in this thread before:

https://twitter.com/DutchSpace/status/1722609536492786015

The image below has been posted in this thread before but was enhanced to show more details:

https://twitter.com/DutchSpace/status/1613486689686528001
DC-201 has no 'shooting star' separable payload module, and has a larger internal volume for the same length (more cylindrical, rather than Dream Chaser's flattened form). Eliminating the forward-facing-window requirement and its associated dorsal hump certainly simplifies things.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: JAFO on 11/11/2023 12:31 pm
Suppose an astronaut had a medical emergency that made it hazardous to return on a higher G capsule like Dragon or Soyuz. Even though it will not be going through the human rating tests, is it possible DC Cargo could be used to return them?
Yeah, they'd have to figure out a way to strap them in, but suppose it was a stroke or cardiac event or whatnot, and NASA was faced with a no-win situation. I wonder if there is sufficient ECS to get the person down to the surface?
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: Zed_Noir on 11/11/2023 02:05 pm
Suppose an astronaut had a medical emergency that made it hazardous to return on a higher G capsule like Dragon or Soyuz. Even though it will not be going through the human rating tests, is it possible DC Cargo could be used to return them?
Yeah, they'd have to figure out a way to strap them in, but suppose it was a stroke or cardiac event or whatnot, and NASA was faced with a no-win situation. I wonder if there is sufficient ECS to get the person down to the surface?
Just strapped the patient to an improvised seat in the patient's IVA suit with portable air supply for at least 6 hours. However it is likely that someone have to accompany the patient down. Also the Cargo Dreamchaser will probably landed at a contingency landing site that is the closest available after the medical emergency is declared. Presuming there will be several portable air supply system stored aboard the ISS for medical evacuation with the Cargo Dreamchaser.
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: FutureSpaceTourist on 12/02/2023 03:43 pm
https://twitter.com/brickmack/status/1730974158895321416

Quote
Dream Chaser jettisons its Shooting Star prior to reentry
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: edzieba on 01/23/2024 07:23 am
https://youtu.be/_7NiBD3KqkQ?t=171

DC201 briefly depicted (2:51) docking in Sierra Space's update video on LIFE testing. IDS rather than CBM, and no service module (Shooting Star).
Title: Re: Sierra Space Dream Chaser DISCUSSION Thread (was SNC)
Post by: JAFO on 01/25/2024 04:45 pm
No presser about the results of testing, must mean the tests are going well?

Quote from: NASA

NASA, Sierra Space Invite Media to See Spaceplane for Cargo Missions
As part of NASA’s efforts to expand commercial resupply in low Earth orbit, media are invited to view Sierra Space’s uncrewed commercial spaceplane ahead of its first demonstration flight for the agency to the International Space Station in 2024.
The Dream Chaser event is scheduled to begin at 10:15 a.m. EST Thursday, Feb. 1, at NASA’s Neil Armstrong Test Facility in Sandusky, Ohio.
For the first time, the spaceplane is coupled with its companion Shooting Star cargo module in a 55-foot-tall vertical stack for environmental testing in the Mechanical Vibration Facility at Armstrong Test Facility’s Space Environments Complex.
During the event, the following officials will provide brief remarks about the agency’s efforts to enable commercial industry, the unique capabilities of the NASA test facility, as well as share more about Dream Chaser and its ongoing testing at NASA Glenn:
 
  • Dr. Jimmy Kenyon, director, NASA’s Glenn Research Center in Cleveland
  • Tom Vice, chief executive officer, Sierra Space
  • A question-and-answer session will follow remarks. Dr. Tom Marshburn, former NASA astronaut and chief medical officer for Sierra Space, also will be in attendance and available for interviews.
    Media interested in attending must RSVP by 2 p.m. Wednesday, Jan. 31, to Brian Newbacher at [email protected] or 216-433-5644.
    Attendance is in-person only and limited to participants, invited guests, and credentialed media.
    Dream Chaser and its cargo module are undergoing testing on NASA’s spacecraft shaker table, exposing the stack to vibrations like those it will experience during launch and re-entry to the Earth’s atmosphere. Armstrong Test Facility is part of NASA Glenn. Located on 6,400 acres, it is home to some of the world’s largest and most capable space simulation test facilities, where ground tests are conducted for the U.S. and international space and aeronautics communities.
    In 2016, NASA awarded a Commercial Resupply Services-2 contract to Sierra Space to resupply the International Space Station with its Dream Chaser spaceplane and companion Shooting Star cargo module. NASA is opening access to space to more science by enabling commercial resupply missions to the International Space Station for the crew members aboard the microgravity laboratory. The agency is helping build a low Earth orbit economy where NASA is one of many customers of U.S. private industry for cargo, crew, and space destinations for the benefit of humanity. As NASA transitions low Earth orbit to industry, the agency also is returning to the Moon as part of Artemis in preparation for Mars.
    Learn more about Dream Chaser at:
    https://go.nasa.gov/3Oe9wi0 (https://go.nasa.gov/3Oe9wi0)

    https://www.nasa.gov/news-release/nasa-sierra-space-invite-media-to-see-spaceplane-for-cargo-missions/ (https://www.nasa.gov/news-release/nasa-sierra-space-invite-media-to-see-spaceplane-for-cargo-missions/)
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