Pros and Cons, Dragon V2, CST-100 and Dream Chaser

[Darren_Hensley]

Like most spacecraft the Dream Chaser has the nozzles for its main engines at the back.  Unfortunately it also has the docking port at the back.  So if anything is attached via the NDS/ILIDS the spacecraft cannot fire its main engines without destroying the 'thing'.

Meaningless.  NDS/ILIDS is not an interface that can support a object during launch.

OK, have we seen specs or images that tell us how the DC mounts to the LV? I got the impression that only the ILIDS was used, and that the DC "undocked from the LV post fairing deployment, eliminating the need for explosive bolts that create debris. Again, I got the "impression" not the facts.

Suppose this were true, then by translation/extension one could make a cargo module, with shielding, to "dock" between the DC and the LV, given proper LV capacity and Fairing room. I suspect that fully hard docked ILIDS were made to take impact, tensional and torsional stresses. If (BIG IF) the specs permit this, then, yes this would be a Pro. A simple leap of faith and design here, but.. I'm looking for the facts. Please discuss.

[Darren_Hensley]

Interesting ideas but we have a major constraint.  With spacecraft the cargo has to be in front of the nozzles.  (Or away from them.)

Like most spacecraft the Dream Chaser has the nozzles for its main engines at the back.  Unfortunately it also has the docking port at the back.  So if anything is attached via the NDS/ILIDS the spacecraft cannot fire its main engines without destroying the 'thing'.

The Orion, Dragon and CST-100 have their docking port at the front and the main engines towards the back and sides.

By attaching the cargo module to Dream Chaser using the undercarriage there is no destructive flame impairment.  This also uses the existing strong points on the spacecraft.

1. Can the landing gear doors be open and close in vacuum without compromising the TPS? Also can the tires on the landing gear and the landing gears themselves be exposed to external vacuum environment?

2. Attitude control would be interesting with your suggested stack configuration.

3. The landing gears are not design to take the loads in your stack configuration. Never mind there is no nose landing gear (the skid is not something you can attached things to).


IMO if you want to move cargo through a CBM port with something like the DC, build a bigger unmanned DC with a CBM port for berthing.

1.  On the current Dream Chaser or the mark 2?  New wheels that can handle vacuum and air tight seals can be added.

2.  The cargo module will need its own RCS controlled from the Dream Chaser.

3.  The spacecraft touches down at over 100 miles per hour.  So the skip can take strong forces.  A metal hand for instance may be able to grab the skip from the side.

The Dream Chaser is a manned return vehicle.  If it is being used to tractor the cargo then the mission probably needs the skills of the pilot.  The EELV, SLS and COTS LV can launch automated cargo modules.

There will have to be some sort of expendable interstage between the cargo and Dream Chaser during launch.

Do you suggest the cargo is mounted to the belly durring launch, but not return?, Or do you suggest that the cargo be retrieved post launch from the expendable interstage Apollo/RMS style? Again a non-reentry package?

PS.. SKID not SKIP or NLG work as well... :-)

[Jim]

OK, have we seen specs or images that tell us how the DC mounts to the LV? I got the impression that only the ILIDS was used, and that the DC "undocked from the LV post fairing deployment, eliminating the need for explosive bolts that create debris. Again, I got the "impression" not the facts.

It isn't used.

[kerlc]

Interesting ideas but we have a major constraint.  With spacecraft the cargo has to be in front of the nozzles.  (Or away from them.)

Oh right, silly me for forgetting something so basic. *facepalms*

Also, that picture looks absolutely stunning. 

[A_M_Swallow]

{snip}
1.  On the current Dream Chaser or the mark 2?  New wheels that can handle vacuum and air tight seals can be added.

2.  The cargo module will need its own RCS controlled from the Dream Chaser.

3.  The spacecraft touches down at over 100 miles per hour.  So the skip can take strong forces.  A metal hand for instance may be able to grab the skip from the side.

The Dream Chaser is a manned return vehicle.  If it is being used to tractor the cargo then the mission probably needs the skills of the pilot.  The EELV, SLS and COTS LV can launch automated cargo modules.

There will have to be some sort of expendable interstage between the cargo and Dream Chaser during launch.

Do you suggest the cargo is mounted to the belly durring launch, but not return?, Or do you suggest that the cargo be retrieved post launch from the expendable interstage Apollo/RMS style? Again a non-reentry package?

{snip}

I was assuming that the cargo module was mounted behind the Dream Chaser during launch similar to the Apollo LEM.  The spacecraft flies back to collect it.

Making the package able to reenter is possible but would increase costs and timescales considerably.  Until we need to reenter 10-20 tonne items KISS.

[A_M_Swallow]

{snip}
Also, that picture looks absolutely stunning. 

Yes, a great photograph.

Credits

From NASA's archive http://mediaarchive.ksc.nasa.gov/detail.cfm?mediaid=66079

I used the version in Wiki Commons uploaded by Craigboy.

[Roy_H]

I can't believe all the wasted effort discussing external cargo. That's what the cargo only version of the Dragon is for and the HTV. No need to complicate crewed versions with this capability.

[baldusi]

I can't believe all the wasted effort discussing external cargo. That's what the cargo only version of the Dragon is for and the HTV. No need to complicate crewed versions with this capability.

The whole point of the discussion is that if the other crewed vehicles can also win some cargo launches, then a second crewed vehicle can be deployed. Dragon has this capability now, but if they are not elected for CRS 2, is a lost capability. JAXA doesn't want to go with HTV further than HTV-7.

[DGH]

I can't believe all the wasted effort discussing external cargo. That's what the cargo only version of the Dragon is for and the HTV. No need to complicate crewed versions with this capability.

Agree.
We need 2-3 Soyuz a year and 1 ATV.
Neither of which are big on unpressurized cargo.
Even when the HTV is retired it is not that big on unpressurized cargo a single Dragon can replace 2 HTVs unpressurized cargo.

[Raj2014]

Does anyone know what are the measurements of the Dragon V2? Height,width with and without the trunk. 

[Darren_Hensley]

OK, have we seen specs or images that tell us how the DC mounts to the LV? I got the impression that only the ILIDS was used, and that the DC "undocked from the LV post fairing deployment, eliminating the need for explosive bolts that create debris. Again, I got the "impression" not the facts.

It isn't used.

I get the impression that some kind of launch frame with explosive bolts is used. And now that would be a Con!

[Jim]

Three words, wow Jim, What book of knowledge you are!

Wow now I get the impression that some kind of launch frame with explosive bolts is used. And now that would be a Con!

More likely a clamp band. 

[darkenfast]

Here's an issue (maybe). What are the requirements for control of the spacecraft by the crew, and how does that affect each of the entrants?  I believe all of them can land autonomously, but what skill requirements are necessary for a crew to return the vehicle to Earth?  I realize that in today's world, even "manual" control is through a computer, but if there is a requirement to fly the spacecraft manually, how do they stack up, and is NASA allowed to consider that as part of the selection process?  How many man-hours of training will be required to land a Dragon or CST versus a Dreamchaser?  Will NASA have to go back to having Pilot Astronauts in addition to Mission Specialists?

[arachnitect]

Here's an issue (maybe). What are the requirements for control of the spacecraft by the crew, and how does that affect each of the entrants?  I believe all of them can land autonomously, but what skill requirements are necessary for a crew to return the vehicle to Earth?  I realize that in today's world, even "manual" control is through a computer, but if there is a requirement to fly the spacecraft manually, how do they stack up, and is NASA allowed to consider that as part of the selection process?  How many man-hours of training will be required to land a Dragon or CST versus a Dreamchaser?  Will NASA have to go back to having Pilot Astronauts in addition to Mission Specialists?

Contractor to charge NASA for crew training.

6. [B.4] Is training of the NASA crew flying the spacecraft included in the CLIN 002 cost/price or is that to be added via contract change later?
Yes it should be included in the CLIN 002 cost/price.

7. [Global] Will the pilot be NASA provided or contractor provided?
The approach should be proposed by the Contractor.
a. If NASA provided, is training of pilot included in CLIN 001 or CLIN 002 pricing?
Yes, pilot training included in CLIN 001 for flight tests and CLIN 002 for missions.

(CLIN 001 = development and test flights, CLIN 002 is "Post Certification Missions," i.e. operational crew rotation missions).

[soldeed]

While Dragon V2 is my favorite of the new space ships, I do not wish failure upon any of them. Currently America has no spacecraft of it's own to fly astronauts. But, in just a few short years, if these efforts don't fail, America's private enterprise will have produced 3 different spacecraft to choose from! In addition to our new official national ship (the Orion) And the Russians will still have only the Soyuz. A while back I heard tell of them designing a new bigger capsule, but am not aware they are actually doing it. And I can't see Russia or China allowing entrepreneurs to have a private space company. Only in america as Elon has said! We are on the cusp of a space golden age!

[Moe Grills]

I'll skip the Dream Chaser & focus in on the conical Dragon V2 & CST-10O with a question:
What will happen to the loser, if the loser is either the Dragon V2 & CST-100?
IMHO I feel safe saying NASA will not choose both conical spacecraft; one will have to be rejected.
It will be an expensive rejection since what will you do with the multimillion dollar test/prototype hardware?
Put the losing submission hardware in a museum while the NASA contract winner puts its hardware in orbit?

[pathfinder_01]

I'll skip the Dream Chaser & focus in on the conical Dragon V2 & CST-10O with a question:
What will happen to the loser, if the loser is either the Dragon V2 & CST-100?
IMHO I feel safe saying NASA will not choose both conical spacecraft; one will have to be rejected.
It will be an expensive rejection since what will you do with the multimillion dollar test/prototype hardware?
Put the losing submission hardware in a museum while the NASA contract winner puts its hardware in orbit?

In theory the looser could bid on cargo as the ISS cargo contracts will be up for bid soon. It would also be in an great position to get the crew contract should an winner of the crew contract run into trouble and NASA decides to rebid it like they did for COTS(i.e. Rocket Plane Kistler to Orbital).

[Rifleman]

IMHO I feel safe saying NASA will not choose both conical spacecraft; one will have to be rejected.

Im not so sure about this. If there is enough funding for 2 winners at 100%, I could easily see them being Dragon and CST100. Nothing against dream chaser, I think it is by far the coolest concept of the 3, but the lifting body design does have some drawbacks as well.

If there is a 100% and a 50% award, I would guess that the 100% would go to either SpaceX or Boeing, and the 50% to Sierra Nevada, but in a 100-100 situation, I would hate to make the bet that they wont go with 2 capsules.

[rayleighscatter]

I'll skip the Dream Chaser & focus in on the conical Dragon V2 & CST-10O with a question:
What will happen to the loser, if the loser is either the Dragon V2 & CST-100?
IMHO I feel safe saying NASA will not choose both conical spacecraft; one will have to be rejected.
It will be an expensive rejection since what will you do with the multimillion dollar test/prototype hardware?
Put the losing submission hardware in a museum while the NASA contract winner puts its hardware in orbit?

Two capsules is still very possible. Blunt body reentry is a basic bit of physics, so unless we suddenly find our idea of physics are in error then NASA would still have dissimilar redundancy since both capsules have different systems.

About the rejections. It will be a blow to any company who is rejected but it won't be a total loss. SpaceX can put the knowledge gained towards their other space programs, and Boeing can apply it towards other space or defense systems, I suspect SNC can probably also apply it to future projects. No matter how it ends all three companies got a couple hundred million in free R&D money.

[mr. mark]

As far as Pro's I would have to give the edge to Boeing's CST-100 as far as flight heritage experience. They "seem" to be the farthest behind in term of development though. SpaceX seems to be the front runner in development. Of course, the November pad abort test will tell the tale so to speak.  As far as Dream Chaser, they've got a long way to go but, they have an aggressive development schedule coming up so, you never know. I've always felt Dream Chaser was the underdog in the hunt one step above Skylon in the pipe dream department. Hope I'm proven wrong. What I hope for is a safe dependable vehicle that can take astronauts to ISS. If we get that then everyone wins. SpaceX, Boeing and Sierra Nevada all have skin in the game elsewhere.