Author Topic: Boeing's CST-100 capsule updates & discussion  (Read 580049 times)

Online ugordan

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Re: Boeing's CST-100 capsule updates & discussion
« Reply #500 on: 04/20/2011 05:42 pm »
Wasn't there something about a F9 with Merlin 1D & a stretch lofting 16 mT? Seems that would cover the issue.

Yes, but it would be one skinny-a$$ rocket. It also has the same problem as Atlas 402 - doesn't exist yet.

Offline docmordrid

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Re: Boeing's CST-100 capsule updates & discussion
« Reply #501 on: 04/20/2011 05:54 pm »
IIRC the difference in F9 and Atlas V core diameter is <4%: 3.66m vs. 3.81m, and Boeing shows F9 as an option in their own literature & imagery.
« Last Edit: 04/20/2011 06:02 pm by docmordrid »
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Online HMXHMX

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Re: Boeing's CST-100 capsule updates & discussion
« Reply #502 on: 04/20/2011 05:58 pm »
2)   Atlas 402 has not flown yet The Delta IV 4,2 will approach a dozen launches by 2014.

So if the choice is an SRB-less Atlas and Delta with 2 SRMs, what's preventing them from going with let's say Atlas 421? If anything, Atlas SRBs don't need TVC so there are fewer failure points.

Not that Delta is a bad choice, I'm just wondering about the reasoning behind that point.

Atlas 421 solves many of the minor problems with 402 and 521 solves even more.

But adds the risk of flying a crewed spacecraft on a vehicle with solids that can't be terminated except by explosives, which then increases the safe separation distance. DreamChaser has the same issue, and as the selection statement notes, concerns about safe abort.  Of all selected CCDEV2 options, only SpaceX will now fly on an all liquid booster (unless Blue Origin plans to use a 402, which doesn't currently exist).

Dream Chaser intends to also use the Atlas 402. I don't think that the Selection Statement meant the abort risks related to the Atlas since those are the same for all spacecrafts using the Atlas 402 (Boeing, Blue Origin and Dream Chaser).

I've seen everything from a (presumed) 402 (w/o solids) to the 431.  At NSS last week, I'm pretty sure the DC model had solids.  Maybe somebody from SNC who is in the know can comment.

Online ugordan

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Re: Boeing's CST-100 capsule updates & discussion
« Reply #503 on: 04/20/2011 06:09 pm »
IIRC the difference in F9 and Atlas V core diameter is <4%: 3.66m vs. 3.81m

Skinny in the sense of height/diameter, a.k.a. fineness ratio.

Online ugordan

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Re: Boeing's CST-100 capsule updates & discussion
« Reply #504 on: 04/20/2011 06:12 pm »
I've seen everything from a (presumed) 402 (w/o solids) to the 431.

I wonder if the 431 would be an interim solution. About how long would re-developing a DEC take, anyway?

Online HMXHMX

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Re: Boeing's CST-100 capsule updates & discussion
« Reply #505 on: 04/20/2011 06:14 pm »
I've seen everything from a (presumed) 402 (w/o solids) to the 431.

I wonder if the 431 would be an interim solution. About how long would re-developing a DEC take, anyway?

All I can say is not too long and not too much.  Maybe somebody from ULA can elaborate.

Offline Jason1701

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Re: Boeing's CST-100 capsule updates & discussion
« Reply #506 on: 04/20/2011 06:15 pm »
Atlas 421 solves many of the minor problems with 402 and 521 solves even more.

There's no difference between 421 and 521 for commercial crew purposes because the standard payload fairings are unnecessary.

Online HMXHMX

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Re: Boeing's CST-100 capsule updates & discussion
« Reply #507 on: 04/20/2011 06:18 pm »
Atlas 421 solves many of the minor problems with 402 and 521 solves even more.

There's no difference between 421 and 521 for commercial crew purposes because the standard payload fairings are unnecessary.

It all depends on the spacecraft.  DC, unlike CST-100, was (at one point) using the 5M aft structure to mitigate the bending loads.  But your basic point is valid; in fact, we need to subtract the fairing cost from launch price estimates when we make comparisons to F9 or other LVs.

Offline yg1968

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Re: Boeing's CST-100 capsule updates & discussion
« Reply #508 on: 04/20/2011 06:28 pm »
2)   Atlas 402 has not flown yet The Delta IV 4,2 will approach a dozen launches by 2014.

So if the choice is an SRB-less Atlas and Delta with 2 SRMs, what's preventing them from going with let's say Atlas 421? If anything, Atlas SRBs don't need TVC so there are fewer failure points.

Not that Delta is a bad choice, I'm just wondering about the reasoning behind that point.

Atlas 421 solves many of the minor problems with 402 and 521 solves even more.

But adds the risk of flying a crewed spacecraft on a vehicle with solids that can't be terminated except by explosives, which then increases the safe separation distance. DreamChaser has the same issue, and as the selection statement notes, concerns about safe abort.  Of all selected CCDEV2 options, only SpaceX will now fly on an all liquid booster (unless Blue Origin plans to use a 402, which doesn't currently exist).

Dream Chaser intends to also use the Atlas 402. I don't think that the Selection Statement meant the abort risks related to the Atlas since those are the same for all spacecrafts using the Atlas 402 (Boeing, Blue Origin and Dream Chaser).

I've seen everything from a (presumed) 402 (w/o solids) to the 431.  At NSS last week, I'm pretty sure the DC model had solids.  Maybe somebody from SNC who is in the know can comment.

According to ULA, all CCDev-1 companies intend to use an Atlas Dual Engine Centaur as their baseline:

Quote
2. Atlas Dual Engine Centaur (DEC) DEC offers significant LEO performance improvements over our current design, and has been baselined by all CCT Companies that we are currently working with.

See page 5:
http://www.ulalaunch.com/site/docs/publications/AtlasDeltaCrewLaunch2010.pdf

I think that the confusion results form the fact that an earlier version of the Dream Chaser was supposed to use the Atlas V 431 but that has since been changed to an Atlas V 402:
http://en.wikipedia.org/wiki/Dream_Chaser_(spacecraft)

See also page 13 of this NASA publication:
http://www.nasa.gov/pdf/475795main_rendezvous_v4n3.pdf

In other words, the image that you saw was likely an old image of the Dream Chaser.
« Last Edit: 04/20/2011 07:39 pm by yg1968 »

Offline Lars_J

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Re: Boeing's CST-100 capsule updates & discussion
« Reply #509 on: 04/20/2011 06:32 pm »
Wasn't there something about a F9 with Merlin 1D & the FH core stretch lofting 16 mT? Seems that would cover the issue.

EDIT: page 2 in this SpaceX PDF. Also check the images - they show the stretch.

That PDF appears to show the standard length F9. Where is the stretch?

Online ugordan

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Re: Boeing's CST-100 capsule updates & discussion
« Reply #510 on: 04/20/2011 06:34 pm »
According to ULA, all CCDev-1 companies intend to use an Atlas Dual Engine Centaur as their baseline:

<snip>

I think that the confusion is that an earlier version of the Dream Chaser was supposed to use the Atlas V 431 but that has since been changed to an Atlas V 402:

That makes sense. I guess we know what will be part of ULA's CCdev 3 proposal...

Offline simonbp

Re: Boeing's CST-100 capsule updates & discussion
« Reply #511 on: 04/20/2011 08:21 pm »
That makes sense. I guess we know what will be part of ULA's CCdev 3 proposal...

CCDEV3 will be for actual flight demonstrations, so ULA wouldn't receive any money directly, only as a subcontractor of one the spacecraft manufactures.

Online edkyle99

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Re: Boeing's CST-100 capsule updates & discussion
« Reply #512 on: 04/20/2011 08:46 pm »
Wasn't there something about a F9 with Merlin 1D & the FH core stretch lofting 16 mT? Seems that would cover the issue.

EDIT: page 2 in this SpaceX PDF. Also check the images - they show the stretch.

The brochure shows the stretched Falcon 1e (as designed for the 125Klbf Merlin), but does not show any stretched Falcon 9 rockets.  The dimensions shown are for the Block 1 Falcon 9, even the drawing for the Heavy. 

Here's my drawing showing my best estimates at the stretched Falcon 9 appearance.
http://www.spacelaunchreport.com/f9-growth.jpg

 - Ed Kyle
« Last Edit: 04/20/2011 09:04 pm by edkyle99 »

Offline yg1968

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Re: Boeing's CST-100 capsule updates & discussion
« Reply #513 on: 04/20/2011 10:01 pm »
That makes sense. I guess we know what will be part of ULA's CCdev 3 proposal...

CCDEV3 will be for actual flight demonstrations, so ULA wouldn't receive any money directly, only as a subcontractor of one the spacecraft manufactures.

Are you sure about that? I am not sure why ULA could not receive funds under CCDev3. The NASA Authorization bill allocates funding for commercial crew capabilities but it says little else about it. I don't see anything in the NASA Authorization Act prohibiting ULA from receiving CCDev-3 money for its EDS or for other human rating work. I imagine that the Dual Engine Centaur could also be funded under CCDev-3.

I believe that some of the 21st century complex funding could be used to build new launch facilities or to make launch site modifications for a crewed Atlas V. 
« Last Edit: 04/20/2011 10:02 pm by yg1968 »

Offline simonbp

Re: Boeing's CST-100 capsule updates & discussion
« Reply #514 on: 04/20/2011 11:54 pm »
The impression I got from the NASA Commercial Office presentation to Space Access was that CCDEV3 would only be demonstration flights. Maybe that will change.
« Last Edit: 04/21/2011 07:45 pm by simonbp »

Offline DGH

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Re: Boeing's CST-100 capsule updates & discussion
« Reply #515 on: 04/21/2011 12:31 am »
So my question still stands. How is your 2) an argument in favor of picking Delta over Atlas?

It does not answer Delta vs Atlas in general.
The original question was an Atlas 402 vs a Delta IV 4,2.
 Answers 1 and 2 only apply to a DEC Atlas.
 Answer 3 is for 400 series Atlas only.

Boeing wants to fly in under 35 months eliminating anything that could slow that down may be important to them.


Offline Ronsmytheiii

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Re: Boeing's CST-100 capsule updates & discussion
« Reply #516 on: 04/28/2011 03:58 pm »

Offline DGH

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Re: Boeing's CST-100 capsule updates & discussion
« Reply #517 on: 05/19/2011 02:02 pm »
Has anybody estimated the pressurized volume of the CST 100?

After looking at http://www.aiaa.org/pdf/industry/presentations/Keith_Reiley.pdf

Especially pages 6 and 12.

I came up with 18-20 cubic meters being moderately conservative.
Well over 50% more then Dragon.

Two numbers given in PDF :
Capsule max diameter 4.56 meters or 179 inches.
Total length including service module 199 inches 5.05 meters.

Estimate Capsule top to bottom over 3 meters.

Offline Robotbeat

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Re: Boeing's CST-100 capsule updates & discussion
« Reply #518 on: 05/19/2011 06:51 pm »
An Apollo-like shape is generally less volume-efficient for a given diameter compared to a capsule like Dragon, remember.
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Offline clongton

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Re: Boeing's CST-100 capsule updates & discussion
« Reply #519 on: 05/19/2011 11:53 pm »
An Apollo-like shape is generally less volume-efficient for a given diameter compared to a capsule like Dragon, remember.

As far as capsules go the Soyuz is about as volume efficient as you get.
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I started my career on the Saturn-V F-1A engine

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