Author Topic: SNC Dream Chaser DISCUSSION Thread  (Read 661375 times)

Offline yg1968

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Re: SNC Dream Chaser DISCUSSION Thread
« Reply #1540 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.
« Last Edit: 01/16/2016 11:27 PM by yg1968 »

Offline Jcc

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Re: SNC Dream Chaser DISCUSSION Thread
« Reply #1541 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.

Offline Star One

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Re: SNC Dream Chaser DISCUSSION Thread
« Reply #1542 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.

Offline Rocket Science

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Re: SNC Dream Chaser DISCUSSION Thread
« Reply #1543 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?
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Online Robotbeat

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Re: SNC Dream Chaser DISCUSSION Thread
« Reply #1544 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?
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Offline Antilope7724

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Re: SNC Dream Chaser DISCUSSION Thread
« Reply #1545 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.

Offline Dante80

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Re: SNC Dream Chaser DISCUSSION Thread
« Reply #1546 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.
« Last Edit: 01/17/2016 01:32 AM by Dante80 »

Online Robotbeat

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Re: SNC Dream Chaser DISCUSSION Thread
« Reply #1547 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.
Chris  Whoever loves correction loves knowledge, but he who hates reproof is stupid.

To the maximum extent practicable, the Federal Government shall plan missions to accommodate the space transportation services capabilities of United States commercial providers. US law http://goo.gl/YZYNt0

Offline yg1968

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Re: SNC Dream Chaser DISCUSSION Thread
« Reply #1548 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. 

Offline Lars-J

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Re: SNC Dream Chaser DISCUSSION Thread
« Reply #1549 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.

Offline okan170

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Re: SNC Dream Chaser DISCUSSION Thread
« Reply #1550 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.

Offline Rocket Science

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Re: SNC Dream Chaser DISCUSSION Thread
« Reply #1551 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... ;)
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Offline BrightLight

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Re: SNC Dream Chaser DISCUSSION Thread
« Reply #1552 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?

Offline Dante80

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Re: SNC Dream Chaser DISCUSSION Thread
« Reply #1553 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.

Offline Rocket Science

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Re: SNC Dream Chaser DISCUSSION Thread
« Reply #1554 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...
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Offline adrianwyard

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Re: SNC Dream Chaser DISCUSSION Thread
« Reply #1555 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.

Offline adrianwyard

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Re: SNC Dream Chaser DISCUSSION Thread
« Reply #1556 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

Offline Antilope7724

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Re: SNC Dream Chaser DISCUSSION Thread
« Reply #1557 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.
« Last Edit: 01/18/2016 05:14 AM by Antilope7724 »

Offline Rocket Science

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Re: SNC Dream Chaser DISCUSSION Thread
« Reply #1558 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...
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Offline Rocket Science

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Re: SNC Dream Chaser DISCUSSION Thread
« Reply #1559 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.
« Last Edit: 01/18/2016 01:13 PM by Rocket Science »
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