Author Topic: Commercial Crew - Discussion Thread 1  (Read 640913 times)

Offline yg1968

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Re: Commercial Crew (CCtCAP) - Discussion Thread
« Reply #480 on: 10/22/2014 08:01 pm »
SNC hasn't actually decided to change to liquid-fueled engines on Dream Chaser.  They just started studying the option.

That is not correct.
A liquid engine has been baselined for DreamChaser. The Hybrid motor has been abandoned.
http://www.parabolicarc.com/2014/08/19/snc-abandons-hybrid-motors-dream-chaser/

Actually, SNC is still making trade studies about the DC engines. Sirangelo refuted (in an interview with AmericaSpace) what was said by Kathy Lueders. No final decision has yet been announced.   
« Last Edit: 10/22/2014 08:03 pm by yg1968 »

Offline docmordrid

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Re: Commercial Crew (CCtCAP) - Discussion Thread
« Reply #481 on: 10/22/2014 10:55 pm »
If SNC is uncertain about DC's engines can we really be surprised if NASA was concerned about a schedule slip? 

Not to mention the problems VG has had with SNC built hybrids. The NASA people weren't locked in a vault.
« Last Edit: 10/22/2014 10:56 pm by docmordrid »
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Offline QuantumG

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Re: Commercial Crew (CCtCAP) - Discussion Thread
« Reply #482 on: 10/22/2014 10:58 pm »
If SNC is uncertain about DC's engines can we really be surprised if NASA was concerned about a schedule slip? 

Investigating alternatives isn't being "uncertain".

Quote from: docmordrid
Not to mention the problems VG has had with SNC built hybrids. The NASA people weren't locked in a vault.

They're completely different motors.. and completely different vehicles.. for completely different purposes.
« Last Edit: 10/22/2014 10:59 pm by QuantumG »
Human spaceflight is basically just LARPing now.

Offline docmordrid

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Re: Commercial Crew (CCtCAP) - Discussion Thread
« Reply #483 on: 10/22/2014 11:05 pm »
If SNC is uncertain about DC's engines can we really be surprised if NASA was concerned about a schedule slip? 

Investigating alternatives isn't being "uncertain".-

Optics. A political term, but politics intrudes everywhere these days.

Quote
Quote from: docmordrid
Not to mention the problems VG has had with SNC built hybrids. The NASA people weren't locked in a vault.

They're completely different motors.. and completely different vehicles.. for completely different purposes.

And likely made using similar processes, and by the same division.
« Last Edit: 10/22/2014 11:05 pm by docmordrid »
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Offline Nindalf

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Re: Commercial Crew (CCtCAP) - Discussion Thread
« Reply #484 on: 10/22/2014 11:20 pm »
Here it is:
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.
There's some more discussion in that topic.

Offline QuantumG

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Re: Commercial Crew (CCtCAP) - Discussion Thread
« Reply #485 on: 10/22/2014 11:31 pm »
The reason SNC has no trouble with their hybrids is that they designed their vehicle around their engines.. as any sensible vehicle engineer would do.
Human spaceflight is basically just LARPing now.

Offline clongton

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Re: Commercial Crew (CCtCAP) - Discussion Thread
« Reply #486 on: 10/23/2014 12:07 am »
SNC hasn't actually decided to change to liquid-fueled engines on Dream Chaser.  They just started studying the option.

That is not correct.
A liquid engine has been baselined for DreamChaser. The Hybrid motor has been abandoned.
http://www.parabolicarc.com/2014/08/19/snc-abandons-hybrid-motors-dream-chaser/

Actually, SNC is still making trade studies about the DC engines. Sirangelo refuted (in an interview with AmericaSpace) what was said by Kathy Lueders. No final decision has yet been announced.   

The decision has been documented. That's all I can say.
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I started my career on the Saturn-V F-1A engine

Offline Patchouli

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Re: Commercial Crew (CCtCAP) - Discussion Thread
« Reply #487 on: 10/23/2014 02:55 am »
SNC hasn't actually decided to change to liquid-fueled engines on Dream Chaser.  They just started studying the option.

That is not correct.
A liquid engine has been baselined for DreamChaser. The Hybrid motor has been abandoned.
http://www.parabolicarc.com/2014/08/19/snc-abandons-hybrid-motors-dream-chaser/

Actually, SNC is still making trade studies about the DC engines. Sirangelo refuted (in an interview with AmericaSpace) what was said by Kathy Lueders. No final decision has yet been announced.   

The decision has been documented. That's all I can say.

I went to the Orbitec web site and found this .

http://www.orbitec.com/propulsion.html

"ORBITEC is also applying the coaxial vortex flow field to hybrid rocket engine systems that produce fuel regression rates significantly higher than conventional hybrid configurations. This increase in fuel regression rate enables the use of a simple circular grain port and leads to significant gains in performance, reliability, and durability of hybrid systems."

It seems they're considering on moving to a simpler round fuel grain port vs a star or rod and tube as Orbitec's votrex flow allows this change.

This should help with combustion instabilities.
« Last Edit: 10/23/2014 03:04 am by Patchouli »

Offline Mike Harris-Stone

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Re: Commercial Crew (CCtCAP) - Discussion Thread
« Reply #488 on: 10/28/2014 01:14 am »
Space News has an article with additional details on the contract decision I've not seen elsewhere and also on the apparent stand off between NASA and congress.

http://www.spacenews.com/article/civil-space/42324house-republicans-clamor-for-commercial-crew-source-selection-document

This is certainly not where I expected Commercial Crew to be at this point.  The more I think about it, the more I think the disparity in the contract amounts ($2 billion!), whatever the technical merits of CST-100, is a potentially big public relations problem for NASA.  I hope all this ends well but I'm getting very concerned.  A storm seems to be brewing.

Offline TrevorMonty

Re: Commercial Crew (CCtCAP) - Discussion Thread
« Reply #489 on: 10/28/2014 01:41 am »
Here is an extract from the article, this states that SNC have still not finalized the main propulsion engines. That is definitely a big cross against them in regards to the selection.


http://redirect.viglink.com/?key=a7e5ffb24b9e84f4f4f6bbd88aa4e5b8&out=http%3A%2F%2Fwww.spacenews.com%2Farticle%2Fcivil-space%2F42324house-republicans-clamor-for-commercial-crew-source-selection-document&subId=9e0e40a51b6ed794dbcfbd46410ba102

Gerstenmaier said he was troubled by “a critical design decision yet to be made regarding different main propulsion systems” for Dream Chaser, which resembles a mini space shuttle.

Offline vt_hokie

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Re: Commercial Crew (CCtCAP) - Discussion Thread
« Reply #490 on: 10/28/2014 02:11 am »
It was a little late in the game for a propulsion change.  Pretty remarkable how DC went from hybrid-palooza to no hybrids at all!


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Re: Commercial Crew (CCtCAP) - Discussion Thread
« Reply #491 on: 10/28/2014 04:25 am »
From the SpaceNews article by Dan Leone:
Quote
Gerstenmaier also disagreed with the members of the source evaluation board about the importance of some planned Dream Chaser features. For example, Gerstenmaier gave less weight to Dream Chaser’s ability to land on runways than did the evaluation board, and was more troubled than the board over some of the remaining technical hurdles in SNC’s proposal.

This hints at the possibility the evaluation board might have come to a preliminary conclusion with recommendations of awards, which might then have been over-ridden by Gerstenmaier. That's speculation, but if it did play out that way the over-ride would look ugly in the court of public opinion, regardless of Gerstenmaier's actual reasons for it.
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Offline woods170

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Re: Commercial Crew (CCtCAP) - Discussion Thread
« Reply #492 on: 10/28/2014 07:48 am »
From the SpaceNews article by Dan Leone:
Quote
Gerstenmaier also disagreed with the members of the source evaluation board about the importance of some planned Dream Chaser features. For example, Gerstenmaier gave less weight to Dream Chaser’s ability to land on runways than did the evaluation board, and was more troubled than the board over some of the remaining technical hurdles in SNC’s proposal.

This hints at the possibility the evaluation board might have come to a preliminary conclusion with recommendations of awards, which might then have been over-ridden by Gerstenmaier. That's speculation, but if it did play out that way the over-ride would look ugly in the court of public opinion, regardless of Gerstenmaier's actual reasons for it.
Yes, because it would invalidate having an evaluation board in the first place.
WARNING: the next few sentences are pure and utter speculation: IF a single person was capable of over-riding the evaluation board it would largely invalidate the usefullness of having an evaluation board. The general purpose of having an evaluation board is to come to a well-considered and weighed conclusion (with regards to the evaluation), a concensus if you will. Having that concensus shoved aside by a single person would indeed not look to well in the court of public opinion. And I suspect it would not look too well in US Congress either.
So I really hope the SpaceNews article has it's facts wrong.
« Last Edit: 10/28/2014 07:49 am by woods170 »

Offline A_M_Swallow

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Re: Commercial Crew (CCtCAP) - Discussion Thread
« Reply #493 on: 10/28/2014 09:24 am »
Space News has an article with additional details on the contract decision I've not seen elsewhere and also on the apparent stand off between NASA and congress.

http://www.spacenews.com/article/civil-space/42324house-republicans-clamor-for-commercial-crew-source-selection-document

This is certainly not where I expected Commercial Crew to be at this point.  The more I think about it, the more I think the disparity in the contract amounts ($2 billion!), whatever the technical merits of CST-100, is a potentially big public relations problem for NASA.  I hope all this ends well but I'm getting very concerned.  A storm seems to be brewing.

Congress can ask NASA what is so urgent about Commercial Crew that it cannot wait a 100 days?
The answer is likely to be politically embarrassing so I suggest that they wait until after the election in case they are one of the politicians being protected.

Offline baldusi

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Re: Commercial Crew (CCtCAP) - Discussion Thread
« Reply #494 on: 10/28/2014 02:15 pm »
Yes, because it would invalidate having an evaluation board in the first place.
WARNING: the next few sentences are pure and utter speculation: IF a single person was capable of over-riding the evaluation board it would largely invalidate the usefullness of having an evaluation board. The general purpose of having an evaluation board is to come to a well-considered and weighed conclusion (with regards to the evaluation), a concensus if you will. Having that concensus shoved aside by a single person would indeed not look to well in the court of public opinion. And I suspect it would not look too well in US Congress either.

It all depends. If the margins of selection was very thin, a very small criteria difference would be well within the rights (and duties) of the Selection Officer. In fact, that's why there's one. If the technical committee had the final weights and criteria, then  there would be no point in having a second stage of selecting officer.
I've got no reason to consider any sort of illegal bias nor wrong doing from Gerst. He did stated a certain difference of criteria on very few points (and it happened across the board), but the structure of ratings was such that I simply don't see an actual impact (sorry, can't go into specifics). The only point that I think could be argued (and still think it is baseless), is one technicality regarding the rating system. When the Source Selection Document is released to the general public, we can go into specifics.
Meanwhile, there's no lobby hand, nor a secret agenda. It might have come down to different set of  criteria.
« Last Edit: 10/28/2014 06:40 pm by Chris Bergin »

Online LouScheffer

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Re: Commercial Crew (CCtCAP) - Discussion Thread
« Reply #495 on: 10/28/2014 03:10 pm »
From the SpaceNews article by Dan Leone:
Quote
Gerstenmaier also disagreed with the members of the source evaluation board about the importance of some planned Dream Chaser features. For example, Gerstenmaier gave less weight to Dream Chaser’s ability to land on runways than did the evaluation board, and was more troubled than the board over some of the remaining technical hurdles in SNC’s proposal.

This hints at the possibility the evaluation board might have come to a preliminary conclusion with recommendations of awards, which might then have been over-ridden by Gerstenmaier. That's speculation, but if it did play out that way the over-ride would look ugly in the court of public opinion, regardless of Gerstenmaier's actual reasons for it.
Yes, because it would invalidate having an evaluation board in the first place.
Not at all.  The top administrator's job is to make the big decisions on spending, risk vs reward, and so on.  But he or she does not have the time (even if they have the expertise) to delve into each designs technical and financial details.  So the evaluation board does that - they visit the vendors, look at the designs in detail, check the financials and proposed schedules, and so on.  Then they report their data to the administrator, who uses it to make a final decision, which may or may not agree with the board.

Lots and lots of processes work this way.  The referees review papers, but the editor decides.  The decadal review has the scientist's preferences, but the funding agencies decide.  Cabinet officers express their views, but the president can decide otherwise.  In most cases it's a sensible division of labor, since neither the technical experts or the administrators have the time (and often the ability) to do the other's job well.

Online Chris Bergin

Re: Commercial Crew (CCtCAP) - Discussion Thread
« Reply #496 on: 10/28/2014 06:41 pm »
Thread trimmed due to off topic post surrounding an idiot's comment.
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Offline newpylong

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Re: Commercial Crew (CCtCAP) - Discussion Thread
« Reply #497 on: 10/29/2014 01:57 pm »
From the SpaceNews article by Dan Leone:
Quote
Gerstenmaier also disagreed with the members of the source evaluation board about the importance of some planned Dream Chaser features. For example, Gerstenmaier gave less weight to Dream Chaser’s ability to land on runways than did the evaluation board, and was more troubled than the board over some of the remaining technical hurdles in SNC’s proposal.

This hints at the possibility the evaluation board might have come to a preliminary conclusion with recommendations of awards, which might then have been over-ridden by Gerstenmaier. That's speculation, but if it did play out that way the over-ride would look ugly in the court of public opinion, regardless of Gerstenmaier's actual reasons for it.
Yes, because it would invalidate having an evaluation board in the first place.
Not at all.  The top administrator's job is to make the big decisions on spending, risk vs reward, and so on.  But he or she does not have the time (even if they have the expertise) to delve into each designs technical and financial details.  So the evaluation board does that - they visit the vendors, look at the designs in detail, check the financials and proposed schedules, and so on.  Then they report their data to the administrator, who uses it to make a final decision, which may or may not agree with the board.

Lots and lots of processes work this way.  The referees review papers, but the editor decides.  The decadal review has the scientist's preferences, but the funding agencies decide.  Cabinet officers express their views, but the president can decide otherwise.  In most cases it's a sensible division of labor, since neither the technical experts or the administrators have the time (and often the ability) to do the other's job well.

Yes and NASA works this way as well. Programs undergo PDR, CDR, and the Brass makes the KDP choices based on the results of those reviews. This is no different. It is Gerst's job to review the data and make the final call.

Offline docmordrid

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Re: Commercial Crew (CCtCAP) - Discussion Thread
« Reply #498 on: 10/29/2014 05:24 pm »
If anything last night's Antares problem  should teach the Congresscritters that redundancy is good - we need more than one provider for launch, cargo and crew. Not saying it will, they're a rather dense lot, but still.
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Offline Patchouli

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Re: Commercial Crew (CCtCAP) - Discussion Thread
« Reply #499 on: 10/29/2014 08:05 pm »
It was a little late in the game for a propulsion change.  Pretty remarkable how DC went from hybrid-palooza to no hybrids at all!



I wonder how hard that would have been to tame and how cost effective it would have been?

I also wonder will the OSC incident cause a reevaluation of the commercial crew?

The full size DC can do much of Cygnus's or Dragon's cargo duties if one gets grounded since it has a similar capacity.
While the CST-100 has a much smaller cargo capacity then either vehicle.

If I was in NASA's place I would be reconsidering the commercial crew decision based on that.
« Last Edit: 10/29/2014 08:13 pm by Patchouli »

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