Author Topic: ASAP still has concerns over Commercial Crew LOC risks  (Read 45645 times)

Offline AncientU

  • Senior Member
  • *****
  • Posts: 6217
  • Liked: 4008
  • Likes Given: 5537
Re: ASAP still has concerns over Commercial Crew LOC risks
« Reply #160 on: 01/23/2018 01:44 PM »
When dealing with quality and safety standards it is irrelevant whether you do something yourself or someone else does it. The same quality standard applies. The SLS's main requirements document should specify its LOC and LOM requirements.

A difference between the SLS and Orion's LOC to the ISS and CCDev LOC needs explaining and authorising. Possibly by Congress.

The SLS having multiple mission types means that instead of having a single LOC it requirements should contain a table of LOCs and LOMs.

Let me put it this way: when was the last time NASA had to explain something to itself?

Answer: Challenger and Columbia.


Additionally: notice the bolded statement above? Well, NASA doesn't agree with it, because they don't require their own vehicle (SLS) to launch unmanned seven times before they put a crewed vehicle on top of it.
It is plain and simple: SLS is a NASA vehicle. As such they DO NOT apply the same standards to SLS, that they apply to a vehicle built by someone else.

Exactly.
This is based on the premise that NASA knows what it is doing in rocketry... see? ::)
"If we shared everything [we are working on] people would think we are insane!"
-- SpaceX friend of mlindner

Offline DarkenedOne

  • Full Member
  • ****
  • Posts: 954
  • Liked: 57
  • Likes Given: 8
Re: ASAP still has concerns over Commercial Crew LOC risks
« Reply #161 on: 01/23/2018 05:05 PM »
1.  CCDev is competing with Soyuz, SLS is not  - The CCDev vehicles are there to replace the Soyuz for routine access to LEO.  It is reasonable that NASA would want the vehicles to be at least as safe as the Soyuz, which has a demonstrated LOC of better than 1:100. 

2.  CCDev launch rate is much higher, therefore it needs to be safer.  The CCDev vehicles are expected to have a launch rate of about 4 per year were as SLS will likely have 1 or less.   Over a 5 year period the CCDev vehicles will fly 20 times.  If we assume a 1/50 LOC per mission that translates into a 1/3 chance of having a LOC event in those 5 years.  Since the flight rate for SLS is so low it can get by with a 1/15 LOC per mission, and still have a lower probability of LOC over that same time period. 

3.  Everyone knows LOC and LOM estimates are just SWAGs anyway.  They have proved to be wildly off in the past.  I do not believe anyone takes them at face value.  The main value in performing the analyst that generates these estimates is that it help identify components in the launch systems that pose the highest risk. 

Online abaddon

  • Full Member
  • ****
  • Posts: 1699
  • Liked: 1159
  • Likes Given: 1001
Re: ASAP still has concerns over Commercial Crew LOC risks
« Reply #162 on: 01/23/2018 05:27 PM »
2.  CCDev launch rate is much higher, therefore it needs to be safer.  The CCDev vehicles are expected to have a launch rate of about 4 per year were as SLS will likely have 1 or less.
Incorrect.  CCDev LVs will launch far more than four times per year.  SpaceX launched 18 times last year.  Atlas V launched what, 8-10?  Both LVs will launch far more frequently than SLS.  The fact that the LVs launch far more frequently than SLS on non-crewed missions improves safety in a way that SLS, without any tangible launches that are not crewed, does not benefit from.

If you want to talk capsules, Dragon 2 and CST will launch more frequently than Orion, true.  But that's only part of the equation.

Offline AncientU

  • Senior Member
  • *****
  • Posts: 6217
  • Liked: 4008
  • Likes Given: 5537
Re: ASAP still has concerns over Commercial Crew LOC risks
« Reply #163 on: 01/23/2018 10:24 PM »
...
Atlas V launched what, 8-10?  ...

6
"If we shared everything [we are working on] people would think we are insane!"
-- SpaceX friend of mlindner

Offline Jim

  • Night Gator
  • Senior Member
  • *****
  • Posts: 32377
  • Cape Canaveral Spaceport
  • Liked: 11063
  • Likes Given: 328
Re: ASAP still has concerns over Commercial Crew LOC risks
« Reply #164 on: 01/23/2018 10:30 PM »
When dealing with quality and safety standards it is irrelevant whether you do something yourself or someone else does it. The same quality standard applies. The SLS's main requirements document should specify its LOC and LOM requirements.

A difference between the SLS and Orion's LOC to the ISS and CCDev LOC needs explaining and authorising. Possibly by Congress.

The SLS having multiple mission types means that instead of having a single LOC it requirements should contain a table of LOCs and LOMs.

Let me put it this way: when was the last time NASA had to explain something to itself?

Answer: Challenger and Columbia.


Additionally: notice the bolded statement above? Well, NASA doesn't agree with it, because they don't require their own vehicle (SLS) to launch unmanned seven times before they put a crewed vehicle on top of it.
It is plain and simple: SLS is a NASA vehicle. As such they DO NOT apply the same standards to SLS, that they apply to a vehicle built by someone else.

Exactly.
This is based on the premise that NASA knows what it is doing in rocketry... see? ::)

And it does.
https://www.nasa.gov/missions

Offline Jim

  • Night Gator
  • Senior Member
  • *****
  • Posts: 32377
  • Cape Canaveral Spaceport
  • Liked: 11063
  • Likes Given: 328
Re: ASAP still has concerns over Commercial Crew LOC risks
« Reply #165 on: 01/23/2018 10:31 PM »
...
Atlas V launched what, 8-10?  ...

6

A needless post.  6, 8 or 10 doesn't matter for the purpose of this discussion

Online meberbs

  • Full Member
  • ****
  • Posts: 1756
  • Liked: 1565
  • Likes Given: 382
Re: ASAP still has concerns over Commercial Crew LOC risks
« Reply #166 on: 01/24/2018 12:57 AM »
This is based on the premise that NASA knows what it is doing in rocketry... see? ::)

And it does.
https://www.nasa.gov/missions
Orbital rocketry is not spacecraft design, these are completely different things.

Also, any credibility NASA had for doing orbital rockets and analyzing their safety was shot when their response to putting crew on the first launch of a brand new rocket was anything other than "No, the risk is too high, it would be unethical to seriously consider that, if you insist, we can do some analysis to prove that."

Offline Jim

  • Night Gator
  • Senior Member
  • *****
  • Posts: 32377
  • Cape Canaveral Spaceport
  • Liked: 11063
  • Likes Given: 328
Re: ASAP still has concerns over Commercial Crew LOC risks
« Reply #167 on: 01/24/2018 01:12 AM »

Orbital rocketry is not spacecraft design, these are completely different things.


Anything with rockets is rocketry.  Orbital doesn't mean anything different, same principles apply across the spectrum of missions.

As for credibility being shot, the same applies companies that do static fires with a spacecraft attached.

Offline pietro

  • Member
  • Posts: 30
  • Hungary, the home of Martians
  • Liked: 10
  • Likes Given: 29
Re: ASAP still has concerns over Commercial Crew LOC risks
« Reply #168 on: 01/24/2018 02:18 AM »
As for credibility being shot, the same applies companies that do static fires with a spacecraft attached.

No, that is progress. Doing something new based on prior positive experience and risk analysis. When there is a failure, analyze it, learn from it, re-do risk analysis, take corrective action, continue with an improved design. Far different from putting people on the first flight of a brand new craft.

Offline kalmes

  • Member
  • Posts: 2
  • Liked: 4
  • Likes Given: 11
Re: ASAP still has concerns over Commercial Crew LOC risks
« Reply #169 on: 01/24/2018 03:11 AM »
I gave up on NASA risk analysis when they made the tortured claim that Ares I would be safer than an EELV.

Ridiculous.


Offline eric_astro

  • Member
  • Posts: 36
  • USA
  • Liked: 3
  • Likes Given: 108
Re: ASAP still has concerns over Commercial Crew LOC risks
« Reply #170 on: 01/24/2018 03:49 AM »
Yeah-
Looking at manned flights since 1961, and Genesis I and II, as my 3 year old daughter would say- "I no like" their LOC estimates.

Offline MaxTeranous

  • Member
  • Posts: 59
  • Liked: 47
  • Likes Given: 10
Re: ASAP still has concerns over Commercial Crew LOC risks
« Reply #171 on: 01/24/2018 10:48 AM »

Orbital rocketry is not spacecraft design, these are completely different things.


Anything with rockets is rocketry.  Orbital doesn't mean anything different, same principles apply across the spectrum of missions.

As for credibility being shot, the same applies companies that do static fires with a spacecraft attached.

Accidents happen. What's important is to learn from them and not do them again. Thus no more spacecraft on static fires.

NASA very nearly lost a crew on STS-1. Excusable as remote/autonomous control wasn't nearly as established as it is nowadays, different time and acceptance of risks, etc. But 30 odd years later those things have changed and they are/were looking at crew on EM-1 !

Offline woods170

  • IRAS fan
  • Senior Member
  • *****
  • Posts: 8379
  • IRAS fan
  • The Netherlands
  • Liked: 4723
  • Likes Given: 1500
Re: ASAP still has concerns over Commercial Crew LOC risks
« Reply #172 on: 01/24/2018 11:18 AM »

Orbital rocketry is not spacecraft design, these are completely different things.


Anything with rockets is rocketry.  Orbital doesn't mean anything different, same principles apply across the spectrum of missions.

As for credibility being shot, the same applies companies that do static fires with a spacecraft attached.

Accidents happen. What's important is to learn from them and not do them again. Thus no more spacecraft on static fires.

NASA very nearly lost a crew on STS-1. Excusable as remote/autonomous control wasn't nearly as established as it is nowadays, different time and acceptance of risks, etc. But 30 odd years later those things have changed and they are/were looking at crew on EM-1 !

What speaks for NASA is that they were asked by the current administration to look into crew on EM-1. NASA did so and (fortunately) concluded that crew on EM-1 was technically possible but not a good idea when viewed from schedule-, financial- and safety repercussions.

NASA never, by themselves, considered putting crew on EM-1. They had learned the lesson from STS-1.
« Last Edit: 01/24/2018 11:20 AM by woods170 »

Offline Jim

  • Night Gator
  • Senior Member
  • *****
  • Posts: 32377
  • Cape Canaveral Spaceport
  • Liked: 11063
  • Likes Given: 328
Re: ASAP still has concerns over Commercial Crew LOC risks
« Reply #173 on: 01/24/2018 01:23 PM »
As for credibility being shot, the same applies companies that do static fires with a spacecraft attached.

No, that is progress. Doing something new based on prior positive experience and risk analysis. When there is a failure, analyze it, learn from it, re-do risk analysis, take corrective action, continue with an improved design. Far different from putting people on the first flight of a brand new craft.

No, that is not progress, it was the same type of hubris as NASA

Online abaddon

  • Full Member
  • ****
  • Posts: 1699
  • Liked: 1159
  • Likes Given: 1001
Re: ASAP still has concerns over Commercial Crew LOC risks
« Reply #174 on: 01/24/2018 02:59 PM »
I gave up on NASA risk analysis when they made the tortured claim that Ares I would be safer than an EELV.
I'm not sure it's fair to compare NASA under Mike Griffin with the NASA of today.

Offline Lar

  • Fan boy at large
  • Global Moderator
  • Senior Member
  • *****
  • Posts: 10427
  • Saw Gemini live on TV
  • A large LEGO storage facility ... in Michigan
  • Liked: 7271
  • Likes Given: 5060
Re: ASAP still has concerns over Commercial Crew LOC risks
« Reply #175 on: 01/24/2018 04:11 PM »
Cancelled is not the same as never existed. BUT how is it relevant? (rhetorical question, don't answer) ... Please, let's not let this turn into a general NASA bashing thread. Thank you.
"I think it would be great to be born on Earth and to die on Mars. Just hopefully not at the point of impact." -Elon Musk
"We're a little bit like the dog who caught the bus" - Musk after CRS-8 S1 successfully landed on ASDS OCISLY

Online envy887

  • Senior Member
  • *****
  • Posts: 4441
  • Liked: 2390
  • Likes Given: 1353
Re: ASAP still has concerns over Commercial Crew LOC risks
« Reply #176 on: 01/24/2018 05:08 PM »
It is a common practice  to go near a fueled rocket.  See Ice teams, red teams, closeout crew, etc.   

It WAS common practice to go near a fueled Shuttle stack. That does not make it great idea.

Does ULA allow ground crew near a fueled Atlas or Delta?

Yes, every launch vehicle contractor has a crew that is set up to go near a fueled launch vehicle for troubleshooting.  It is not a rare event.

How would SpaceX do that once they start LOX load? At that point they only have a few minutes to launch before the warming prop could cause issues. Not enough time to troubleshoot or fix much of anything before they have to scrub the launch and detank anyway.

Online meberbs

  • Full Member
  • ****
  • Posts: 1756
  • Liked: 1565
  • Likes Given: 382
Re: ASAP still has concerns over Commercial Crew LOC risks
« Reply #177 on: 01/24/2018 05:46 PM »
What speaks for NASA is that they were asked by the current administration to look into crew on EM-1. NASA did so and (fortunately) concluded that crew on EM-1 was technically possible but not a good idea when viewed from schedule-, financial- and safety repercussions.

NASA never, by themselves, considered putting crew on EM-1. They had learned the lesson from STS-1.

Quote from: nasaspaceflight.com
NASA will not put a crew on EM-1, cites cost not safety as main reason

Quote from: Lightfoot
At the end of the day, we found it technically feasible to fly crew on EM-1, as long as we had a commitment of additional resources and schedule

Quote from: NASA Office of the administrator
Based on this study, NASA concluded crew could have flown on Exploration Mission-1 (EM-1), provided timely and sufficient funding, with an increased risk acceptance and moving the launch schedule to most likely early 2020.

While it is good that NASA would not have done this study without external prompting, this is not NASA learning their lesson. Safety is a technical criteria, so saying "technically feasible" means that the safety risks are acceptable, STS-1's lesson was that the risks are not acceptable without a strong reason that crew is required.

Point is analysis based LOC estimates are not as good as flight history, so demonstration requirements applied to CC are good, but should also be applied to all NASA programs. There is nothing magical about NASA that makes their analysis more accurate.

Orbital rocketry is not spacecraft design, these are completely different things.
Anything with rockets is rocketry.  Orbital doesn't mean anything different, same principles apply across the spectrum of missions.
Jim, What are you saying here? NASA missions are generally science missions requiring returning high quality data and operating over a long period of time. These challenges are not related to the challenges of building a rocket that can reliably put them in space to begin with. Rocketry is not involved with most NASA missions, even RCS thrusters aren't necessarily required. Even if you insist on counting RCS thrusters/delta-V engines as rocketry, it is still completely different technology than what is used in orbital class rockets.
« Last Edit: 01/24/2018 05:59 PM by meberbs »

Online SWGlassPit

  • I break space hardware
  • Full Member
  • ****
  • Posts: 542
  • Liked: 392
  • Likes Given: 60
Re: ASAP still has concerns over Commercial Crew LOC risks
« Reply #178 on: 01/24/2018 08:31 PM »
While it is good that NASA would not have done this study without external prompting, this is not NASA learning their lesson. Safety is a technical criteria, so saying "technically feasible" means that the safety risks are acceptable, STS-1's lesson was that the risks are not acceptable without a strong reason that crew is required.

Point is analysis based LOC estimates are not as good as flight history, so demonstration requirements applied to CC are good, but should also be applied to all NASA programs. There is nothing magical about NASA that makes their analysis more accurate.

You really cannot look at that analysis in a vacuum.  You have to consider who directed it and what their motivations are -- i.e., who it's written for.  If the administration comes and says, "what would it take to make this happen?" and you say "it's not safe," you didn't answer their question, and you would quickly find yourself without a job.  You have to answer the question asked.  In this case, they pointed out that making it safe would cost too much.

There are only two reasons governments don't do something: money and politics.  You have to frame the base answer of "it's not safe" in terms of those two, which is what the study did.

Offline kalmes

  • Member
  • Posts: 2
  • Liked: 4
  • Likes Given: 11
Re: ASAP still has concerns over Commercial Crew LOC risks
« Reply #179 on: 01/24/2018 11:20 PM »
I gave up on NASA risk analysis when they made the tortured claim that Ares I would be safer than an EELV.
I'm not sure it's fair to compare NASA under Mike Griffin with the NASA of today.

That's a good point, and the political pressure at the time is very different than today.

Still, I don't like the attitude that safety can simply be bought with enough paperwork. Analysis is certainly essential, but eventually you run into "unknown-unknowns" with novel systems, and it's hard to get to very high levels of reliability without experience with the system. NASA's response was that if they spend enough money, EM-1 will be safe.

There is a lot of heritage in EM-1, and I would ride it given the chance  :). But I don't believe the first launch will be as safe as an Atlas or Falcon flight, no matter how much you prepare. Practical experience with systems that are used over and over again is extremely important to reliability, and I don't see NASA's safety culture embracing that fact.

Tags: