Author Topic: ASAP still has concerns over Commercial Crew LOC risks  (Read 21078 times)

Offline the_other_Doug

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Re: ASAP still has concerns over Commercial Crew LOC risks
« Reply #40 on: 09/05/2017 04:36 PM »
I think both the Star liner and Dragon beat Soyuz by having less separation events and three parachutes.

Actually, Crew Dragon will have four parachutes.  But Apollo 15 did teach the lesson of having a one-chute-out safety margin... :)
-Doug  (With my shield, not yet upon it)

Offline ChrisWilson68

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Re: ASAP still has concerns over Commercial Crew LOC risks
« Reply #41 on: 09/30/2017 02:12 AM »
I think both the Star liner and Dragon beat Soyuz by having less separation events and three parachutes.

Though a crewed version of Dream Chaser in theory should beat both of them as far as landing safety goes.

That was one one part of STS that actually had a good safety record.

I disagree.  To land on a runway you give up being able to do ballistic re-entry.  Star liner and Dragon can lose all active control and go balistic and they'll come down fine.  All they need is the parachutes to pop open in a single event.  Space planes need control surfaces and active control all the way down.  It's much more complexity, which means more things that can go wrong.

Dragon is the safest in concept because it has a backup for the parachutes -- it can fire its Super Dracos if the parachutes don't open for some reason.

Offline rayleighscatter

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Re: ASAP still has concerns over Commercial Crew LOC risks
« Reply #42 on: 09/30/2017 09:50 PM »
Capsules can lose active control if they're already on the correct reentry path. Otherwise it will orbit forever, reenter too steep, or skip and then reenter too steep.

Offline Nibb31

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Re: ASAP still has concerns over Commercial Crew LOC risks
« Reply #43 on: 09/30/2017 09:56 PM »
Capsules can lose active control if they're already on the correct reentry path. Otherwise it will orbit forever, reenter too steep, or skip and then reenter too steep.

That is true for any reentry vehicle regardless of shape.

Offline wilbobaggins

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Re: ASAP still has concerns over Commercial Crew LOC risks
« Reply #44 on: 11/07/2017 06:16 AM »
I think both the Star liner and Dragon beat Soyuz by having less separation events and three parachutes.

Though a crewed version of Dream Chaser in theory should beat both of them as far as landing safety goes.

That was one one part of STS that actually had a good safety record.

I disagree.  To land on a runway you give up being able to do ballistic re-entry.  Star liner and Dragon can lose all active control and go balistic and they'll come down fine.  All they need is the parachutes to pop open in a single event.  Space planes need control surfaces and active control all the way down.  It's much more complexity, which means more things that can go wrong.

Dragon is the safest in concept because it has a backup for the parachutes -- it can fire its Super Dracos if the parachutes don't open for some reason.
I really hope they have added the software to do this. Just as CRS-7 dragon was lost due to lack of software to pop off nose cone it would be crap to loose a crew because parashutes failed despite having enough hydrazene in the tank for a landing.

Yes they have given up propulsive landing but only I think to the safety standard to do it every time. At the point of total parashutes failure who gives a darn what the chance of a safe propulsive landing is, it is their only hope!

Then again the chance of it firing when the parashutes are fine and shredding parashutes should be considered.


« Last Edit: 11/17/2017 11:09 AM by Chris Bergin »

Offline Space Ghost 1962

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Re: ASAP still has concerns over Commercial Crew LOC risks
« Reply #45 on: 11/12/2017 05:40 PM »
FWIW, to increase mission LOC/LOM now ... fly mission. Analyze. Rework. Fly again.

Why this doesn't happen ... IMO ... too much works too well ... the flights are cheaper/quicker than a certain bigger capsule ... CC converges on provable safety limits ... there then is pressure to actually fly crews.

Once crews start flying on CC, then there's pressure on the bigger capsule to do same. But it can't for cost/reasons, so everyone gets used to CC flying crew and the bigger capsule not flying crew.

This ends up not helping the big capsule, even though it should (a means to prove elements of big capsule with crew).

Because Congress doesn't want CC to follow Soyuz, they want the "big capsule" to. And, they can always blame CC for not flying, because "its too unsafe". Circular.

add:

What if CRS finds booster reuse is effective and accepts for flights? Then likewise CC might arrive at the same conclusion. NASA might be able to do a "block buy" and get perhaps 20-30 CRS/CC flights for every big capsule flight.

How might 20-30 CRS/CC flights ... benefit LOC/LOM assessment/improvement? How much of this could also feed back into big capsule refinement? Might even improve Soyuz.
« Last Edit: 11/12/2017 05:46 PM by Space Ghost 1962 »

Offline rayleighscatter

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Re: ASAP still has concerns over Commercial Crew LOC risks
« Reply #46 on: 11/12/2017 08:14 PM »

NASA might be able to do a "block buy" and get perhaps 20-30 CRS/CC flights for every big capsule flight.

What mission requires 30 CRS flights?

As upset as everyone gets for trying to invent missions for Orion then there's obviously no need to do it for CC either.

Offline Space Ghost 1962

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Re: ASAP still has concerns over Commercial Crew LOC risks
« Reply #47 on: 11/12/2017 08:56 PM »

NASA might be able to do a "block buy" and get perhaps 20-30 CRS/CC flights for every big capsule flight.

What mission requires 30 CRS flights?

As upset as everyone gets for trying to invent missions for Orion then there's obviously no need to do it for CC either.
Missed the point. And its CRS/CC flights, because the same configuration could be used for both. Duh.

The point is that actual, repeated flight data of vehicle gives you bounds/reasons/means for safety improvement.

Not static, ground determined analysis. Sorry if I was unclear.

Edited by Lar.
« Last Edit: 11/14/2017 10:04 AM by Lar »

Offline A_M_Swallow

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Re: ASAP still has concerns over Commercial Crew LOC risks
« Reply #48 on: 11/12/2017 09:01 PM »

NASA might be able to do a "block buy" and get perhaps 20-30 CRS/CC flights for every big capsule flight.

What mission requires 30 CRS flights?

As upset as everyone gets for trying to invent missions for Orion then there's obviously no need to do it for CC either.

30 CRS flights would support multiple Moon landings. Using 5 tonne payloads it will take a while to construct a lunar base. At 40 tonnes payload to the Moon entire buildings can be delivered in one go.

Offline woods170

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Re: ASAP still has concerns over Commercial Crew LOC risks
« Reply #49 on: 11/13/2017 07:13 AM »

NASA might be able to do a "block buy" and get perhaps 20-30 CRS/CC flights for every big capsule flight.

What mission requires 30 CRS flights?

As upset as everyone gets for trying to invent missions for Orion then there's obviously no need to do it for CC either.
Missed the point. And its CRS/CC flights, because the same configuration could be used for both. Duh.

The point is that actual, repeated flight data of vehicle gives you bounds/reasons/means for safety improvement.

Not static, ground determined analysis. Perhaps I need to resort to purple crayon to get my point across?  ::)
Your point is clear. Two little flaws though:
- There won't be 30 missions to inform crew safety, not even when you add Cargo Dragon v2 missions into the mix.
- Purely commercial, non-NASA missions, such as the planned circumlunar mission, do not inform crew safety because NASA insight into those will be almost non-existent.

Right now the CRS/CCP providers need NASA to survive. As such they are willing to put up with the additional crew-safety burden that NASA places on them. But IMO there will come a time when at least one of those providers no longer needs NASA to achieve its goals. When that time comes it will shed NASA and its associated burdensome bureaucracy. Regardless of its his current habit of praising NASA.
« Last Edit: 11/13/2017 07:14 AM by woods170 »

Online pathfinder_01

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Re: ASAP still has concerns over Commercial Crew LOC risks
« Reply #50 on: 11/13/2017 07:50 AM »


Because Congress doesn't want CC to follow Soyuz, they want the "big capsule" to. And, they can always blame CC for not flying, because "its too unsafe". Circular.

add:

What if CRS finds booster reuse is effective and accepts for flights? Then likewise CC might arrive at the same conclusion. NASA might be able to do a "block buy" and get perhaps 20-30 CRS/CC flights for every big capsule flight.

How might 20-30 CRS/CC flights ... benefit LOC/LOM assessment/improvement? How much of this could also feed back into big capsule refinement? Might even improve Soyuz.

1.  This isn't a Congress problem. Congress wants SLS because it creates the most jobs. Orion less so. Therefore Orion development takes a back seat to SLS development. It isn't like Apollo and the early space race where no new rockets were developed specifically for Mercury and Gemini(as that would only delay things) and Apollo used the Saturn 1B(which was an upgrade of an existing rocket) for a number of test flights. This is an ASAP problem. If they were interested in improving the safety of Orion they could always fly some of them on Delta IV heavy but that would require development which would take even more budget(or reduce budget to SLS, therefore delay is the better Option).

2.  There would only be limited data from Commercial Crew that would be relevant to Orion or Soyuz as one system was in development before commercial crew and the other was operational long before. The Russians already have a much more relevant data set for Soyuz and it' successors.

3. As much as I would love a block buy of 20-30 flight this isn't a good reason.  20-30 flights would improve Dragon 2 and Starliner by finding the problems that only experience could sort out. They say little to nothing about Orion.
« Last Edit: 11/13/2017 07:56 AM by pathfinder_01 »

Offline Space Ghost 1962

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Re: ASAP still has concerns over Commercial Crew LOC risks
« Reply #51 on: 11/13/2017 09:59 PM »
NASA might be able to do a "block buy" and get perhaps 20-30 CRS/CC flights for every big capsule flight.
What mission requires 30 CRS flights?
The point is that actual, repeated flight data of vehicle gives you bounds/reasons/means for safety improvement.
Your point is clear. Two little flaws though:
- There won't be 30 missions to inform crew safety, not even when you add Cargo Dragon v2 missions into the mix.
- Purely commercial, non-NASA missions, such as the planned circumlunar mission, do not inform crew safety because NASA insight into those will be almost non-existent.
1. Builds on my point. We think of such vehicles as a limiting cost and so minimize to fewest use. Which caps are ability to reach ASAP's desired LOC. Past LV reuse, things get safer/cheap in net when we get to a fair fraction of 100. SX likely to reach hundreds of missions off of reuse, so we're likely to reach comparative numbers to Shuttle.
2. AF contracts require all launches to "inform" on LV performance. A similar means to inform on crew safety under appropriate convention (possible in US but not Europe given certain laws) could supply such, part of adventurer contract of carriage.

Am quite serious about means to achieve best provable crew vehicle LOC. Which is potentially transferable to other vehicles.

Quote
Right now the CRS/CCP providers need NASA to survive. As such they are willing to put up with the additional crew-safety burden that NASA places on them. But IMO there will come a time when at least one of those providers no longer needs NASA to achieve its goals. When that time comes it will shed NASA and its associated burdensome bureaucracy. Regardless of its his current habit of praising NASA.
Yes we are both looking at the same thing. Beyond NASA. Where its just an occasional client.

BTW, there are many "NASA's" inside of NASA. True of other agencies/ministries. Some see this too.

Difference might be about where and how to achieve said "pivot". Perhaps as temporary conservator? Thus the above.

Offline rayleighscatter

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Re: ASAP still has concerns over Commercial Crew LOC risks
« Reply #52 on: 11/25/2017 01:56 PM »
NASA might be able to do a "block buy" and get perhaps 20-30 CRS/CC flights for every big capsule flight.
What mission requires 30 CRS flights?
The point is that actual, repeated flight data of vehicle gives you bounds/reasons/means for safety improvement.
Your point is clear. Two little flaws though:
- There won't be 30 missions to inform crew safety, not even when you add Cargo Dragon v2 missions into the mix.
- Purely commercial, non-NASA missions, such as the planned circumlunar mission, do not inform crew safety because NASA insight into those will be almost non-existent.
1. Builds on my point. We think of such vehicles as a limiting cost and so minimize to fewest use. Which caps are ability to reach ASAP's desired LOC. Past LV reuse, things get safer/cheap in net when we get to a fair fraction of 100. SX likely to reach hundreds of missions off of reuse, so we're likely to reach comparative numbers to Shuttle.
2. AF contracts require all launches to "inform" on LV performance. A similar means to inform on crew safety under appropriate convention (possible in US but not Europe given certain laws) could supply such, part of adventurer contract of carriage.

Am quite serious about means to achieve best provable crew vehicle LOC. Which is potentially transferable to other vehicles.

Quote
Right now the CRS/CCP providers need NASA to survive. As such they are willing to put up with the additional crew-safety burden that NASA places on them. But IMO there will come a time when at least one of those providers no longer needs NASA to achieve its goals. When that time comes it will shed NASA and its associated burdensome bureaucracy. Regardless of its his current habit of praising NASA.
Yes we are both looking at the same thing. Beyond NASA. Where its just an occasional client.

BTW, there are many "NASA's" inside of NASA. True of other agencies/ministries. Some see this too.

Difference might be about where and how to achieve said "pivot". Perhaps as temporary conservator? Thus the above.

So what you are proposing is that commercial providers surrender their technology and data to the public good? Because that proposal isn't compatible with the current proprietary nature. Unless the intent is to create a de-facto eternal duopoly.

Offline Space Ghost 1962

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Re: ASAP still has concerns over Commercial Crew LOC risks
« Reply #53 on: 11/26/2017 06:00 PM »
So what you are proposing is that commercial providers surrender their technology and data to the public good?
Would you please explain this otherwise irrational conclusion?

Referenced posts say nothing of the kind. Perhaps something else not visible, possibly emotional, is being triggered?

Honestly have no idea where this comes from in the above discussion and would like to know if substantive, because it entirely escapes me and frankly no I don't comment to annoy anyone here as that is my only conclusion as to meaning.

Quote
Because that proposal isn't compatible with the current proprietary nature. Unless the intent is to create a de-facto eternal duopoly.
When has anyone advocated that, please?

Don't get any of this. Asking for advice/help from others, as I'm completely at sea here - help!

Online AncientU

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Re: ASAP still has concerns over Commercial Crew LOC risks
« Reply #54 on: 11/27/2017 07:33 PM »
...

Quote
Right now the CRS/CCP providers need NASA to survive. As such they are willing to put up with the additional crew-safety burden that NASA places on them. But IMO there will come a time when at least one of those providers no longer needs NASA to achieve its goals. When that time comes it will shed NASA and its associated burdensome bureaucracy. Regardless of its his current habit of praising NASA.
Yes we are both looking at the same thing. Beyond NASA. Where its just an occasional client.
...

NASA is asking for one crew flight per year from each of its two providers.  Both GS and EM have said that the demand for tourist flights is surprisingly robust -- which easily translates to more than one flight per year.  Why is 'Beyond NASA' envisioned as so desolate?
« Last Edit: 11/27/2017 07:34 PM by AncientU »
"If we shared everything [we are working on] people would think we are insane!"
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Online AncientU

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Re: ASAP still has concerns over Commercial Crew LOC risks
« Reply #55 on: 11/27/2017 07:40 PM »
So what you are proposing is that commercial providers surrender their technology and data to the public good?
Would you please explain this otherwise irrational conclusion?

Referenced posts say nothing of the kind. Perhaps something else not visible, possibly emotional, is being triggered?

Honestly have no idea where this comes from in the above discussion and would like to know if substantive, because it entirely escapes me and frankly no I don't comment to annoy anyone here as that is my only conclusion as to meaning.

Quote
Because that proposal isn't compatible with the current proprietary nature. Unless the intent is to create a de-facto eternal duopoly.
When has anyone advocated that, please?

Don't get any of this. Asking for advice/help from others, as I'm completely at sea here - help!

Haven't a clue what is meant here...
"If we shared everything [we are working on] people would think we are insane!"
-- SpaceX friend of mlindner

Offline Space Ghost 1962

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Re: ASAP still has concerns over Commercial Crew LOC risks
« Reply #56 on: 11/28/2017 12:30 AM »
Thank you. It's nice to get confirmation that it's not just me. Worry sometimes that I say something that is wrong in a way I don't anticipate.

Offline rayleighscatter

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Re: ASAP still has concerns over Commercial Crew LOC risks
« Reply #57 on: 12/28/2017 07:13 PM »
Ok, to simplify then:


The point is that actual, repeated flight data of vehicle gives you bounds/reasons/means for safety improvement.

How is this accomplished? Do other companies get access to the flight/machine data, or do all future contacts go to the same two companies because they're the only ones who have access to the data needed to improve safety.

Unless you have another thought in mind on how, say, Lockheed could benefit from SpaceX's proprietary heatshield designs and data.
« Last Edit: 12/28/2017 08:52 PM by rayleighscatter »

Offline Space Ghost 1962

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Re: ASAP still has concerns over Commercial Crew LOC risks
« Reply #58 on: 12/28/2017 09:01 PM »
Ok, to dumb it down then:


The point is that actual, repeated flight data of vehicle gives you bounds/reasons/means for safety improvement.

How is this accomplished? Do other companies get access to the flight/machine data, or do all future contacts go to the same two companies because they're the only ones who have access to the data needed to improve safety.

Unless you have another thought in mind on how, say, Lockheed could benefit from SpaceX's proprietary heatshield designs and data.
Perhaps you are unaware of prior practice.

All past HSF vehicles "inform" on safety/"best practices". Apart from proprietary implementation "flight data". Various groups/agencies/institutions are issued study contracts to take mission flight data and issue a study to find/characterize specific risks. This is used by those including ASAP to feed back to vendors/providers what to look for in refining/qualifying HSF SC/components/subsystems for use. At least with earlier vehicles/modules.

So, there's this new snazzy thing called "Big data", where how this is communicated is in specific "non flight data" form that fits into everyone's models, to specifically address particular concerns. (It's cleverly done so you can't abstract performance data from it.)

It's a similar treatment to how other aerospace standards of practice are improved upon.

But no,  not letting everyone see each others "stuff", but learning from "incidents". Like with airlines/munitions.

Oh, and there are legal/contractual terms too. Not like the "bad old days".

Offline envy887

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Re: ASAP still has concerns over Commercial Crew LOC risks
« Reply #59 on: 01/17/2018 04:03 PM »
SpaceX's view on the prop loading and COVP issues, from Hans Koenigsmann's testimony

Quote
At SpaceX, every design and operation decision is driven by safety and reliability. SpaceX recognizes that
some proposed operating procedures for the crew transportation system differ from those on the Space
Shuttle Program. SpaceX has elected to adopt certain approaches, including propellant loading after
astronauts have been secured in the spacecraft and the launch escape system is enabled, because they offer
the potential to improve safety for both astronauts and ground crew. Under SpaceX’s operations plan, after
astronauts board the spacecraft, the ground crew will close out the vehicle and will leave the launch site.
Launch vehicle propellant loading will begin only after the escape system is armed. This approach ensures
that astronauts have escape capability during any time propellant is on the launch vehicle, and it does not
expose ground crew to unnecessary risk. Notably, the Space Shuttle continued loading liquid hydrogen for
three hours (“Space Shuttle Replenish” procedure) after astronauts were aboard; propellant loading on
Falcon 9 consumes approximately 30 minutes, reducing the time astronauts are exposed to loading
operations.

We have also worked closely with NASA to further enhance the robustness of our composite overwrapped
pressure vessels (COPVs) and to ensure NASA is comfortable with their performance in a variety of flight
environments. We are confident that this process is safe, and we are working closely with NASA to
complete the ongoing, rigorous analysis necessary to achieve certification.
https://democrats-science.house.gov/sites/democrats.science.house.gov/files/documents/Koenigsmann%20Testimony.pdf

Not sure I agree with this logic (as risk and exposure time are not necessarily directly correlated) but it sounds like SpaceX expects to certify this prop loading procedure.

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