Author Topic: ASAP still has concerns over Commercial Crew LOC risks  (Read 45780 times)

Offline Steven Pietrobon

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Re: ASAP still has concerns over Commercial Crew LOC risks
« Reply #120 on: 01/20/2018 04:45 AM »
Why can't SpaceX not use super cooled LOX and land the rocket on the drone ship?  Super cooling is what 12% more LOX than standard?  The Dragon II is only going to LEO.

My calculations showed a 9.8% increase in LOX density. RP-1 density increases by 2.6%. Having to use NBP LOX would mean SpaceX would have to requalify their engines for the higher temperature propellants as well as then having seven flights with the corresponding loss of performance.

With Apollo, LES activation on a stable stack would, I imagine render the stack unusable at best, destroy it at worst. Is this likely true for Falcon too?

If the LES has to be activated, its because the vehicle is about to go kablooey.
Akin's Laws of Spacecraft Design #1:  Engineering is done with numbers.  Analysis without numbers is only an opinion.

Offline Johnnyhinbos

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Re: ASAP still has concerns over Commercial Crew LOC risks
« Reply #121 on: 01/20/2018 05:49 AM »
When NASA apply the 1/270 and seven flights criteria* to SLS with Orion, I'll start listening to this nonsense.
Until then, it is just bureaucratic spinelessness.

* Oh, and add no turbo blade cracking on RS-25s...

Iíve been wondering about this - and perhaps this is now thread misplaced- but why doesnít the ďseven flight prior flight history before flying crewĒ criteria apply to SLS? I know itís based on a few flight experienced components, but itís still an unknown rocket.

And why doesnít the turbo cracking concern apply to its engines (I recall reading a rather lengthy report, I think by AR, on the issues with the RS-25  and on suggested modifications that never were implemented).

That ASAP / NASA doesnít apply the same criteria mystifies me (and Iím trying to keep politics out of this, though perhaps itís impossible).
John Hanzl. Author, action / adventure www.johnhanzl.com

Offline deruch

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Re: ASAP still has concerns over Commercial Crew LOC risks
« Reply #122 on: 01/20/2018 06:10 AM »
That is why the huge success of COTS/CRS model was not repeated for CCP: it upset their established way-of-doing-things too much when applied on a bigger scale.

COTS model of using SAAs instead of contracts wasn't repeated for CCP because it wouldn't allow NASA to dictate any changes due to the limitations of SAAs.  Which would mean that the providers might develop systems that NASA would never agree to use for crew rotations.  Without NASA as an anchor client spending that amount of money to develop a HSF vehicle isn't reasonable.
Shouldn't reality posts be in "Advanced concepts"?  --Nomadd

Offline joek

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Re: ASAP still has concerns over Commercial Crew LOC risks
« Reply #123 on: 01/20/2018 06:55 AM »
That is why the huge success of COTS/CRS model was not repeated for CCP: it upset their established way-of-doing-things too much when applied on a bigger scale.

COTS model of using SAAs instead of contracts wasn't repeated for CCP because it wouldn't allow NASA to dictate any changes due to the limitations of SAAs.  Which would mean that the providers might develop systems that NASA would never agree to use for crew rotations.  Without NASA as an anchor client spending that amount of money to develop a HSF vehicle isn't reasonable.

Appears much of this discussion is due to a misunderstanding of how and when OTA (Other Transaction Authority) as used for SAA's can be applied (e.g., COTS, CCxCap) vs. FAR acquisition rules (e.g, CRS, CCtCap).

There are specific rules that NASA must abide by, and the NASA IG concurred that the current approach is consistent with Congressional direction and law.  Ask yourself why CRS required a FAR contract vs. COTS which was executed under an SAA.

If you understand the what and why, great.  If not, go fish.  You don't like the rules?  Write a letter to your Congress-critter.  In any case, stop whining about it.


Offline su27k

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Re: ASAP still has concerns over Commercial Crew LOC risks
« Reply #124 on: 01/20/2018 07:26 AM »
That's 19 times in a row since the last fuelling explosion on 1 September 2016 with AMOS 6.
Wrong, static fires fully fuel the vehicle, and every launch has been preceded by a static fire.  The originally cited 38 is correct.

Actually it's even higher than that since there're at least 4 last minute aborts (Intelsat 35e had two in a row), total is more like 42.

Offline obi-wan

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Re: ASAP still has concerns over Commercial Crew LOC risks
« Reply #125 on: 01/20/2018 06:17 PM »
With Apollo, LES activation on a stable stack would, I imagine render the stack unusable at best, destroy it at worst. Is this likely true for Falcon too?

If the LES has to be activated, its because the vehicle is about to go kablooey.
It's an interesting point, though - Starliner, with its abort engines inside the service module, are doing a "fire in the hole" abort that would almost certainly blow out the upper dome of the Centaur LH2 tank and initiate a conflagration, regardless of the prior state of the vehicle. Dragon, like the NASA launch abort system tractor rockets, cants the thrust outboard, so there's no direct plume impact to the launch vehicle. It's not beyond the realm of possibility that the F9 would still be usable following an inadvertent abort.

Offline butters

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Re: ASAP still has concerns over Commercial Crew LOC risks
« Reply #126 on: 01/20/2018 06:36 PM »
Assuming Dragon 2 still flies its demo missions, not only does it place the burden on NASA (and ASAP) on wrestling with the political demons as to CC missions, it also captures the fact that the process has arrived at a reasonable conclusion, and can be used as a model for BFS (and perhaps later BO capsules).

SpaceX has learned their lesson, and Blue Origin is paying attention. They will embrace FAA regulation for all future human spacecraft and invite NASA to purchase transportation services if they so choose. But they're never going to develop a spacecraft to NASA requirements ever again. The money is not worth the strings attached.

Offline woods170

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Re: ASAP still has concerns over Commercial Crew LOC risks
« Reply #127 on: 01/20/2018 06:51 PM »
Assuming Dragon 2 still flies its demo missions, not only does it place the burden on NASA (and ASAP) on wrestling with the political demons as to CC missions, it also captures the fact that the process has arrived at a reasonable conclusion, and can be used as a model for BFS (and perhaps later BO capsules).

SpaceX has learned their lesson, and Blue Origin is paying attention. They will embrace FAA regulation for all future human spacecraft and invite NASA to purchase transportation services if they so choose. But they're never going to develop a spacecraft to NASA requirements ever again. The money is not worth the strings attached.

Indeed. It is the very reason why it was so difficult to figure out HOW to fund BFS/BFR. You don't want NASA involved, because they will muck things up (again) but that also means you don't get NASA funding.

But I think in this case the advantages outweigh the disadvantages.

Offline Jim

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Re: ASAP still has concerns over Commercial Crew LOC risks
« Reply #128 on: 01/21/2018 05:16 PM »
With Apollo, LES activation on a stable stack would, I imagine render the stack unusable at best, destroy it at worst. Is this likely true for Falcon too?

If the LES has to be activated, its because the vehicle is about to go kablooey.
It's an interesting point, though - Starliner, with its abort engines inside the service module,

No, the abort engines are on the outside

Offline Jim

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Re: ASAP still has concerns over Commercial Crew LOC risks
« Reply #129 on: 01/21/2018 05:23 PM »
Seems to me we have two historically rare failure modes: failure while fueling and failure while fueled in a stable state on the pad. The second has been "normalized" as it is the current practice. The true risk of each is probably unknown (and unknowable statistically due to the the problem of defining the tail of the distribution).

I'd personally risk fewer people. I put a very high price on human life. I'd take a failure risk that killed 4 people 5 times as often than one that killed 20 people in one go.

That would stupid and worse because after the first of 5 times, you are making people go back into a known riskier situation.

Offline rockets4life97

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Re: ASAP still has concerns over Commercial Crew LOC risks
« Reply #130 on: 01/21/2018 05:24 PM »
Seems to me we have two historically rare failure modes: failure while fueling and failure while fueled in a stable state on the pad. The second has been "normalized" as it is the current practice. The true risk of each is probably unknown (and unknowable statistically due to the the problem of defining the tail of the distribution).

I'd personally risk fewer people. I put a very high price on human life. I'd take a failure risk that killed 4 people 5 times as often than one that killed 20 people in one go.

That would stupid and worse because after the first of 5 times, you are making people go back into a known riskier situation.

Thanks for taking the bait. Yes! So if 4 people were ever killed 1 one time. You can guarantee there will be an extensive investigation and a fix. Much better than 20 people dying!

Offline Jim

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Re: ASAP still has concerns over Commercial Crew LOC risks
« Reply #131 on: 01/21/2018 05:26 PM »
Seems to me we have two historically rare failure modes: failure while fueling and failure while fueled in a stable state on the pad. The second has been "normalized" as it is the current practice. The true risk of each is probably unknown (and unknowable statistically due to the the problem of defining the tail of the distribution).

I'd personally risk fewer people. I put a very high price on human life. I'd take a failure risk that killed 4 people 5 times as often than one that killed 20 people in one go.

That would stupid and worse because after the first of 5 times, you are making people go back into a known riskier situation.

Thanks for taking the bait. Yes! So if 4 people were ever killed 1 one time. You can guarantee there will be an extensive investigation and a fix. Much better than 20 people dying!

20 people aren't going to die in the first place because it is safer because the same issue would have happened and no people would be around it.
« Last Edit: 01/21/2018 05:28 PM by Jim »

Offline deruch

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Re: ASAP still has concerns over Commercial Crew LOC risks
« Reply #132 on: 01/21/2018 05:50 PM »
That is why the huge success of COTS/CRS model was not repeated for CCP: it upset their established way-of-doing-things too much when applied on a bigger scale.

COTS model of using SAAs instead of contracts wasn't repeated for CCP because it wouldn't allow NASA to dictate any changes due to the limitations of SAAs.  Which would mean that the providers might develop systems that NASA would never agree to use for crew rotations.  Without NASA as an anchor client spending that amount of money to develop a HSF vehicle isn't reasonable.

Appears much of this discussion is due to a misunderstanding of how and when OTA (Other Transaction Authority) as used for SAA's can be applied (e.g., COTS, CCxCap) vs. FAR acquisition rules (e.g, CRS, CCtCap).

There are specific rules that NASA must abide by, and the NASA IG concurred that the current approach is consistent with Congressional direction and law.  Ask yourself why CRS required a FAR contract vs. COTS which was executed under an SAA.

If you understand the what and why, great.  If not, go fish.  You don't like the rules?  Write a letter to your Congress-critter.  In any case, stop whining about it.

Don't be obtuse.  NASA could certainly have structured CCtCap such that it could be executed under OTA instead of FAR rules.  But, it would have limited the scope of the agreements to strictly generic development without providing utility to the agency and it would have eliminated their ability to set requirements narrowly to meet their specific needs (present or future).  So, they couldn't have used it for anything after the crewed demonstrations, which likely wouldn't have had NASA astronauts flying on them.  After that point, there would have been a contract under FAR rules for modifications, certification, and any post-certification missions.  A bit clunky, and potentially high financial risk to the providers.  But, it was certainly an available option.  It would have been perfectly equivalent to COTS in that respect which needed the follow-on FAR contract of CRS to allow NASA to actually get use from the developed vehicles.  There were plenty of reasons for NASA not liking that approach but their inability to direct and enforce changes to the capsules (via setting performance requirements) was seen as unacceptable for HSF. 
Shouldn't reality posts be in "Advanced concepts"?  --Nomadd

Offline woods170

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Re: ASAP still has concerns over Commercial Crew LOC risks
« Reply #133 on: 01/22/2018 06:13 AM »

To me, it just feels wrong that we trust a LAS to work on a rocket when it is flying, subsonic, transonic, supersonic, at Max-Q, 

It is because it is the only method available.  It is not the best or safest method when there are other available on the ground.  That is why slidewire and elevators are used.

I think there is an assumption that it is "not the best or safest method"  Have the slidewires or elevators ever been used in an emergency? They certainly do not sound like the quickest way to get clear of a rocket. The LAS has been proved in the case of Soyuz 7K-ST 16L. Only after events happen does NASA seem to reconsider 'change'.

You can't prove the safety of something simply by doing it. 5 out of 6 people would tell you russian roulette is perfectly safe.  You have to understand the system as best as reasonably possible.

There are still many many concerns over any form of LAS. For instance, nearly all of them trust parachutes in an environment that includes several tons of rapidly propagating shrapnel.

That is primarily a concern for pad aborts/near ground aborts only given that only those low-level altitude aborts require fast deployment of the parachutes.
Point is however that LAS is designed to carry the capsule to well above and out of any propagating shrapnel cloud.
The parachute concern is mainly an academic one because some folks are overly concerned that in the most unlikely of all shrapnel-propagation scenario's one-or-more parachutes might be holed by shrapnel.

Well, AMOS-6 has provided us with nice, hard, data-points. The SpaceX pad abort scenario has been super-imposed over the catastrophic AMOS-6 explosion (and I don't mean the YouTube home-made versions, but the special-studies investigation done by NASA and SpaceX, under CCtCAP, in the wake of AMOS-6).

And guess what: the propagation of shrapnel never even got close to the under-parachute portion of the pad abort trajectory. Which is a clear data-point that the design of the LAS (to carry the capsule sufficiently far away from the kaboom) is sound. And mind you: hard data beats academic exercise.
« Last Edit: 01/22/2018 06:15 AM by woods170 »

Offline whatever11235

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Re: ASAP still has concerns over Commercial Crew LOC risks
« Reply #134 on: 01/22/2018 07:47 AM »


Can you please expand on this? Why are rules not the same? As I understand it, NASA is collaborating heavily with SpaceX on Dragon2 design. How is it different with regards to their vendors for SLS/Orion?
« Last Edit: 01/23/2018 01:49 PM by Chris Bergin »

Offline woods170

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Re: ASAP still has concerns over Commercial Crew LOC risks
« Reply #135 on: 01/22/2018 09:59 AM »
I'll pick this one up for Jim given that he has answered this very question many, many times, and people still keep asking the question.

Basically:
On Orion and SLS NASA runs the show entirely, down the smallest little details. They are involved in everything and the contractors don't do anything without NASA permission. For example: NASA tells Boeing: go build SLS with a core stage driven by four RS-25s and boosted by two 5-segment ATK SRBs using the design you'll find in your mailbox".

On CCP NASA sets high-level *cough* requirements and basically tells the contractors: "Realize those requirements the way you see fit. Just as long as your solutions meet the requirements".
For example: NASA tells Boeing: go do your thing as long as it gets us a service that can transport 4 astronauts to the ISS.
NASA than engages in insight and oversight into what the contractors do. But the solutions are conceived, developed, integrated and tested by the contractors and are not the brainchild of NASA.
And exactly for this reason does NASA not automatically trust the contractor's solutions. Those solutions need to prove themselves. And that's why - for example - Falcon 9 Block 5 needs to fly at least seven times before it can launch crew. It is also why - for example - the contractors will have to prove that they meet the 1-in-270 LOC requirement.

Naturally, NASA will trust its own design for SLS with just one unmanned test-flight but not trust someone else's design until it has flown seven times.

That's it. Plain and simple. Don't like it? Too bad, because this is the reality for SLS/Orion vs. CCP. And it is not going to change.
« Last Edit: 01/23/2018 01:48 PM by Chris Bergin »

Offline mn

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Re: ASAP still has concerns over Commercial Crew LOC risks
« Reply #136 on: 01/22/2018 12:48 PM »


Please clarify:

Does this mean that their design doesn't need to meet the 1/270 requirement?

Or because they designed it they are confident that it does indeed meet that requirement?
« Last Edit: 01/23/2018 01:49 PM by Chris Bergin »

Offline woods170

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Re: ASAP still has concerns over Commercial Crew LOC risks
« Reply #137 on: 01/22/2018 01:17 PM »
I'll pick this one up for Jim given that he has answered this very question many, many times, and people still keep asking the question.

Basically:
On Orion and SLS NASA runs the show entirely, down the smallest little details. They are involved in everything and the contractors don't do anything without NASA permission. For example: NASA tells Boeing: go build SLS with a core stage driven by four RS-25s and boosted by two 5-segment ATK SRBs using the design you'll find in your mailbox".

On CCP NASA sets high-level *cough* requirements and basically tells the contractors: "Realize those requirements the way you see fit. Just as long as your solutions meet the requirements".
For example: NASA tells Boeing: go do your thing as long as it gets us a service that can transport 4 astronauts to the ISS.
NASA than engages in insight and oversight into what the contractors do. But the solutions are conceived, developed, integrated and tested by the contractors and are not the brainchild of NASA.
And exactly for this reason does NASA not automatically trust the contractor's solutions. Those solutions need to prove themselves. And that's why - for example - Falcon 9 Block 5 needs to fly at least seven times before it can launch crew. It is also why - for example - the contractors will have to prove that they meet the 1-in-270 LOC requirement.

Naturally, NASA will trust its own design for SLS with just one unmanned test-flight but not trust someone else's design until it has flown seven times.

That's it. Plain and simple. Don't like it? Too bad, because this is the reality for SLS/Orion vs. CCP. And it is not going to change.

Please clarify:

Does this mean that their design doesn't need to meet the 1/270 requirement?

Or because they designed it they are confident that it does indeed meet that requirement?

If SLS/Orion would be flying the same mission profile (crew to ISS) than IMO it would have to meet the 1/270 requirement.
However, SLS/Orion is not intended for Crew-to-ISS missions. The LOC/LOM numbers for the SLS/Orion combo are different (and, as far as I know) not generally known to the public.

And yes: because NASA designed its own vehicles and "runs the show" for its own vehicles NASA is confident its own vehicles will meet its own requirements. One clear indicator to this is that ASAP has been reporting on the CCP LOC numbers for years now but hasn't spent a single word, on the LOC numbers for SLS/Orion, in their reporting.
« Last Edit: 01/22/2018 01:18 PM by woods170 »

Offline mn

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Re: ASAP still has concerns over Commercial Crew LOC risks
« Reply #138 on: 01/22/2018 01:18 PM »


And I should add that I think there is nothing wrong with stating that SLS is a different type of mission and we accept a higher risk for those missions
« Last Edit: 01/23/2018 01:49 PM by Chris Bergin »

Online scdavis

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Re: ASAP still has concerns over Commercial Crew LOC risks
« Reply #139 on: 01/22/2018 04:45 PM »
And yes: because NASA designed its own vehicles and "runs the show" for its own vehicles NASA is confident its own vehicles will meet its own requirements. One clear indicator to this is that ASAP has been reporting on the CCP LOC numbers for years now but hasn't spent a single word, on the LOC numbers for SLS/Orion, in their reporting.

This makes perfect sense, understandable on a human and organizational level. NASA trusts its own engineers and processes -- outside organizations somewhat less. The more the external company's design and process differs from NASA, the more they want to validate independently.

A question from some outside of NASA, including some on this forum, is whether NASA is putting the correct level of trust in their internal work and the right amount of skepticism on external work.

Points in favor of NASA trusting self/skeptical of external designs:
* Have run human spaceflight programs for decades
* Responsible for primary design of multiple HSF vehicles

Points against:
* LOC incidents on shuttle suggests shouldn't trust self so highly.
* Placing crew on only second lift off of SLS. Really? Suggests acceptance of huge risk on in-house design. [1]
* Tales from insiders and outsiders of stifling bureaucracy.
* Haven't designed a new HSF vehicle in decades until SLS/Orion.
* The HSF project they *are* leading as chief designer is monstrously expensive and late. We can blame Congress all we want, but in the end NASA is responsible.

Given this open question, when NASA chooses to put crew on the second flight of SLS while requiring Boeing and SpaceX to prove a very high level of reliability, it looks like bias. [1]

As the customer, of course NASA can require whatever they want of their vendor. But as a citizen served by NASA, I'd like to see our space agency make optimum use of its internal and external talent. Maybe they are doing exactly that -- the evidence is hard to see. Or perhaps it's more fair to say: a large ship turns slowly.

[1] Granting: SLS/Orion so terrifically expensive to fly that they cannot choose otherwise.

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