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#540 by Jim on 17 Sep, 2022 15:05
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If NASA really cared about enhanced reliability through dissimilar redundancy, they would have required both Crew Dragon and Starliner to be compatible with both F9 and Atlas V (or other human-rated LVs).
Not, not true. That doesn't enhance reliability enough to make it worth the cost. How many extra .xxxx9999s are needed? -
#541 by DanClemmensen on 17 Sep, 2022 15:45
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I agree with you. My comment was in the context of a stand-down due to a failure. The premise (not mine) was that an LV failure would cause the LV (either Atlas V or F9) to be "grounded" for human launch. I do not believe that the statistics would require such a grounding, but if NASA disagrees, then the grounding would effectively ground the associated spacecraft. That's not a probability, its a certainty if the LV is grounded.
If NASA really cared about enhanced reliability through dissimilar redundancy, they would have required both Crew Dragon and Starliner to be compatible with both F9 and Atlas V (or other human-rated LVs).
Not, not true. That doesn't enhance reliability enough to make it worth the cost. How many extra .xxxx9999s are needed? -
#542 by Hamish.Student on 18 Sep, 2022 04:18
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I agree with you. My comment was in the context of a stand-down due to a failure. The premise (not mine) was that an LV failure would cause the LV (either Atlas V or F9) to be "grounded" for human launch. I do not believe that the statistics would require such a grounding, but if NASA disagrees, then the grounding would effectively ground the associated spacecraft. That's not a probability, its a certainty if the LV is grounded.
If NASA really cared about enhanced reliability through dissimilar redundancy, they would have required both Crew Dragon and Starliner to be compatible with both F9 and Atlas V (or other human-rated LVs).
Not, not true. That doesn't enhance reliability enough to make it worth the cost. How many extra .xxxx9999s are needed?
I also agree with Jim, but Cygnus provides a poignant example of the argument in question. -
#543 by woods170 on 18 Sep, 2022 15:02
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I’m in favor of redundant operational crew access systems. A Falcon 9 failure would mean an automatic stand down of Dragon, probably for at least 6 months and possibly a year. That’s too long.
Sucks that the only other option is Starliner, but it’s better than nothing.
Emphasis mine.
Your statement is not supported by previous happenings:
- The partial failure of CRS-1 led to stand down of less than 5 months. In fact, it was not even a stand down at all, because the flight rate of F9 was - at that time - roughly once in every 5 months.
- The worst incident that F9 ever experienced was the CRS-7 mission. Which led to a stand down of just 5 months and 3 weeks.
- The AMOS-6 incident resulted in a stand down of just 4 months. -
#544 by edkyle99 on 18 Sep, 2022 18:03
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- The AMOS-6 incident resulted in a stand down of just 4 months.
Yes, but it was 15 months before Falcon 9 launched again from heavily damaged SLC 40. SpaceX and NASA were lucky that LC 39A was just becoming available at that right time.
- Ed Kyle -
#545 by Vettedrmr on 18 Sep, 2022 18:20
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- The AMOS-6 incident resulted in a stand down of just 4 months.
Yes, but it was 15 months before Falcon 9 launched again from heavily damaged SLC 40. SpaceX and NASA were lucky that LC 39A was just becoming available at that right time.
- Ed Kyle
But that's a non-issue now, as there are two (or more?) launch sites. -
#546 by Robotbeat on 18 Sep, 2022 18:27
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I said Dragon, not Falcon 9.I’m in favor of redundant operational crew access systems. A Falcon 9 failure would mean an automatic stand down of Dragon, probably for at least 6 months and possibly a year. That’s too long.
Sucks that the only other option is Starliner, but it’s better than nothing.
Emphasis mine.
Your statement is not supported by previous happenings:
- The partial failure of CRS-1 led to stand down of less than 5 months. In fact, it was not even a stand down at all, because the flight rate of F9 was - at that time - roughly once in every 5 months.
- The worst incident that F9 ever experienced was the CRS-7 mission. Which led to a stand down of just 5 months and 3 weeks.
- The AMOS-6 incident resulted in a stand down of just 4 months.
There’s only one launch site for Dragon. And I’m sure NASA would insist on some recertification of Falcon 9 before putting crew on it again. That’s why I said 6 months at a minimum, and probably longer.
It took 20 months to fly crew on the same launch vehicle and spacecraft after Apollo 1.
32 months after Challenger. 30 months after Columbia.
6 months is likely the bare minimum & I doubt it would be less than 12. Has NASA gotten less risk averse since shuttle and Apollo?
These are good arguments for having star liner and f9 and starship available. -
#547 by abaddon on 18 Sep, 2022 23:25
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After the most recent Soyuz failure NASA let their astronauts fly on Soyuz much more speedily than any of those timeframes. Depending on what exactly the failure was, a F9 return to flight could be similarly rapid.
I still (barely) support Boeing as a redundancy for commercial crew. Eventually it should actually become real… -
#548 by woods170 on 19 Sep, 2022 09:14
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- The AMOS-6 incident resulted in a stand down of just 4 months.
Yes, but it was 15 months before Falcon 9 launched again from heavily damaged SLC 40. SpaceX and NASA were lucky that LC 39A was just becoming available at that right time.
- Ed Kyle
No offense Ed, but you are moving the goalposts. It does not matter that the launch vehicle launched from another launchpad. It's about the time required to get the launch vehicle back to flight.
SpaceX moved to TWO launchpads on the East Coast exactly because they knew that a on-pad failure could cripple their bread-and-butter operation for too long a time. And that decision was proven to be fully justified by Amos-6. The added bonus effect was supporting a higher launch cadence.
West coast does not require a second pad. Launch cadence from there is way too low (only one out of every seven launches) to be a threat to SpaceX bread-and-butter, in case of an Amos-6 type on-pad accident. -
#549 by woods170 on 19 Sep, 2022 09:45
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Seriously? Of all the examples you picked this one as the first to support your argument? Your whole premise was about a launch vehicle failure (F9) grounding Dragon for up to a year, due to recertification required for Falcon 9.
I said Dragon, not Falcon 9.I’m in favor of redundant operational crew access systems. A Falcon 9 failure would mean an automatic stand down of Dragon, probably for at least 6 months and possibly a year. That’s too long.
Sucks that the only other option is Starliner, but it’s better than nothing.
Emphasis mine.
Your statement is not supported by previous happenings:
- The partial failure of CRS-1 led to stand down of less than 5 months. In fact, it was not even a stand down at all, because the flight rate of F9 was - at that time - roughly once in every 5 months.
- The worst incident that F9 ever experienced was the CRS-7 mission. Which led to a stand down of just 5 months and 3 weeks.
- The AMOS-6 incident resulted in a stand down of just 4 months.
There’s only one launch site for Dragon. And I’m sure NASA would insist on some recertification of Falcon 9 before putting crew on it again. That’s why I said 6 months at a minimum, and probably longer.
It took 20 months to fly crew on the same launch vehicle and spacecraft after Apollo 1.
Apollo 1 was a failure not of a the launch vehicle, but of the spacecraft. You cannot even use this example to try to make your case.32 months after Challenger.
Another bad example. Challenger exposed a major design flaw which required a ground up redesign of a major element of the STS stack. That takes time, particularly when done by contractors under direct NASA guidance and steering.
After 176 launches it is rather unlikely that any F9 failure is going to expose a major design flaw. Such a flaw would have manifested itself a long time ago. And it did: Amos-6. Which was *check's notes* six years and 148 launches ago.30 months after Columbia.
Another bad example. Columbia happened because a design flaw, that was known AND understood to exist, finally reached the point where NASA ran out of luck. STS-27 was the close call that should have shaken things up (and didn't).
The stand down for this one was so long because it required trying to work around a basic design flaw that could not be fixed without completely redesigning the entire shuttle system. No such similar, non-solvable, fundamental design flaw exists in the F9 architecture, as evidenced by the huge string of successful F9 launches.6 months is likely the bare minimum & I doubt it would be less than 12. Has NASA gotten less risk averse since shuttle and Apollo?
You are carelessly overlooking the fact that Challenger and Columbia were NASA-owned vehicles. But in case of CCtCAP, and by extension F9/Dragon, NASA buys a service. It is up to SpaceX to prove that F9 is safe enough to fly again. Certification and RE-certification requirements are all in the CCtCAP contract. In this case SpaceX has to (again) succesfully fly F9 seven times in a 'frozen' configuration. That would put the duration of the stand down at something like 5 months: 4 months for the investigation and implementation of the fixes, including all the required NASA reviews (they did the same for CRS-7 and Amos-6 in similar time frames), and one month to fly the required seven uncrewed missions. After that NASA has no valid excuse to refuse resuming crew launches on F9/Dragon. Any further delay would be squarely caused by NASA bureaucracy, not by the service not being ready and available to NASA.These are good arguments for having star liner and f9 and starship available.
I agree with you that having two dissimalar systems available to provide similar services is a good thing. But as evidenced by my replies above I disagree with you about your projected timelines. Also: mentioning Starship here makes no sense. Starship never will be part of CCP. -
#550 by meekGee on 19 Sep, 2022 11:56
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Imagine what if Boeing botches CFT or just walks away. The program would hardly be affected
I said Dragon, not Falcon 9.I’m in favor of redundant operational crew access systems. A Falcon 9 failure would mean an automatic stand down of Dragon, probably for at least 6 months and possibly a year. That’s too long.
Sucks that the only other option is Starliner, but it’s better than nothing.
Emphasis mine.
Your statement is not supported by previous happenings:
- The partial failure of CRS-1 led to stand down of less than 5 months. In fact, it was not even a stand down at all, because the flight rate of F9 was - at that time - roughly once in every 5 months.
- The worst incident that F9 ever experienced was the CRS-7 mission. Which led to a stand down of just 5 months and 3 weeks.
- The AMOS-6 incident resulted in a stand down of just 4 months.
There’s only one launch site for Dragon. And I’m sure NASA would insist on some recertification of Falcon 9 before putting crew on it again. That’s why I said 6 months at a minimum, and probably longer.
It took 20 months to fly crew on the same launch vehicle and spacecraft after Apollo 1.
32 months after Challenger. 30 months after Columbia.
6 months is likely the bare minimum & I doubt it would be less than 12. Has NASA gotten less risk averse since shuttle and Apollo?
These are good arguments for having star liner and f9 and starship available.
In a way dissimilar redundancy will have then worked - one vendor failed, and the other (unexpected one) saved the day.
Right now, operational issues with F9 will get resolved faster than Boeing/ULA can respond with extra flights anyway. -
#551 by Robotbeat on 19 Sep, 2022 12:39
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CFT will actually be crewed, though. They can make it a long duration mission if they really wanted to. So if it had a problem, it would be similar to Dragon having a problem.
And yeah, I agree it would be vindication in a way of the two-vendor approach. -
#552 by Robotbeat on 19 Sep, 2022 12:41
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After the most recent Soyuz failure NASA let their astronauts fly on Soyuz much more speedily than any of those timeframes. Depending on what exactly the failure was, a F9 return to flight could be similarly rapid.
That is a good point.
I still (barely) support Boeing as a redundancy for commercial crew. Eventually it should actually become real…
But Starliner IS real and has completed its uncrewed test flight, all the way to ISS and back. There’s virtually no difference between this and doing a crewed launch other than actually loading the life support system, but that’s not hard to characterize on the ground.
Since the uncrewed test was successful, I’m confident it’s Ready for crew. -
#553 by edkyle99 on 19 Sep, 2022 13:04
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None taken!- The AMOS-6 incident resulted in a stand down of just 4 months.
Yes, but it was 15 months before Falcon 9 launched again from heavily damaged SLC 40. SpaceX and NASA were lucky that LC 39A was just becoming available at that right time.
- Ed Kyle
No offense Ed,Quotebut you are moving the goalposts. It does not matter that the launch vehicle launched from another launchpad. It's about the time required to get the launch vehicle back to flight.
Since this is a CST-100 thread, I'll note that both Starliner and Crew Dragon launch from one dedicated launch pad each. NASA has expressed concern about potential damage to LC 39 from SH/SS and I suppose Falcon 9/Heavy activities. Brand new Vulcan will soon be trying to launch from SLC 41. Destructive launch pad accidents are historically rare (at least in recent decades), but can happen, and the likelihood surely increases with the growing launch rates we are seeing. With only one launch pad each, NASA needs both crewed launch systems to be operational to provide backup for that possibility.
SpaceX moved to TWO launchpads on the East Coast exactly because they knew that a on-pad failure could cripple their bread-and-butter operation for too long a time. And that decision was proven to be fully justified by Amos-6. The added bonus effect was supporting a higher launch cadence.
- Ed Kyle -
#554 by DanClemmensen on 19 Sep, 2022 16:35
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The difference is that Starliner has done this exactly once after either one or two failures depending on how you count the first OFT-2 scrub. By contrast, Crew Dragon has done it eight times, with no failures, so it has a longer statistical history.After the most recent Soyuz failure NASA let their astronauts fly on Soyuz much more speedily than any of those timeframes. Depending on what exactly the failure was, a F9 return to flight could be similarly rapid.
That is a good point.
I still (barely) support Boeing as a redundancy for commercial crew. Eventually it should actually become real…
But Starliner IS real and has completed its uncrewed test flight, all the way to ISS and back. There’s virtually no difference between this and doing a crewed launch other than actually loading the life support system, but that’s not hard to characterize on the ground.
Since the uncrewed test was successful, I’m confident it’s Ready for crew.
By NASA tradition and by contract, it's not ready for crew until after successful completion and evaluation of the CFT. You are using your own private definition of the term, which you are of course free to do. -
#555 by Robotbeat on 19 Sep, 2022 19:21
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If it’s not ready for crew, then it’s not ready for CFT, which involves putting on crew.
The difference is that Starliner has done this exactly once after either one or two failures depending on how you count the first OFT-2 scrub. By contrast, Crew Dragon has done it eight times, with no failures, so it has a longer statistical history.After the most recent Soyuz failure NASA let their astronauts fly on Soyuz much more speedily than any of those timeframes. Depending on what exactly the failure was, a F9 return to flight could be similarly rapid.
That is a good point.
I still (barely) support Boeing as a redundancy for commercial crew. Eventually it should actually become real…
But Starliner IS real and has completed its uncrewed test flight, all the way to ISS and back. There’s virtually no difference between this and doing a crewed launch other than actually loading the life support system, but that’s not hard to characterize on the ground.
Since the uncrewed test was successful, I’m confident it’s Ready for crew.
By NASA tradition and by contract, it's not ready for crew until after successful completion and evaluation of the CFT. You are using your own private definition of the term, which you are of course free to do.
I should point out, IIRC, that Boeing/NASA have proposed before the idea of the first Starliner crew flight as being a longer mission. It’s not just my own idea. In a contingency scenario, I can’t see why it wouldn’t be considered acceptable. -
#556 by Surfdaddy on 20 Sep, 2022 00:13
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As I recall, the Crew Demo-2 on Dragon was extended on the ISS and the astronauts even did a space walk. So some precedent has been set.
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#557 by DanClemmensen on 20 Sep, 2022 01:29
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As I recall, the Crew Demo-2 on Dragon was extended on the ISS and the astronauts even did a space walk. So some precedent has been set.
When NASA thought Starliner would fly before Crew Dragon, they planned an extended CFT for Starliner. The reason is simple: there had been no US crewed spacecraft to ISS since 2011. NASA was paying Roscosmos for seats, and the US side of ISS was understaffed. Extending the CFT mission was logistically simple since there was ample space in ISS. But Crew Dragon flew first, so NASA extended Demo-2 instead of extending Starliner CFT.
They won't extend CFT now, because there is no reason to do so and the logistics are awkward, with contention for space inside the ISS and for docking ports. Also, There had not been a failed Crew Dragon flight prior to Demo-2, while there have been one or (arguably) two failed Starliner missions.
If you think the Demo-2 extension is a precedent using Starliner operationally prior to completion and evaluation of CFT, you might of course be correct, but I don't see it. NASA could do that, but they could also just fly Crew Dragon anyway, or they could just depend on the US astronaut that is still in the ISS due to the Soyuz seat swap to keep the place running, just as they did from 2011 to 2020. I think we are discussing only two potential missions here: replacement of Crew-6 in the Spring of 2023 or Crew-7 in the Fall of 2023. This is such a narrow case that it's not worth speculating about.
Going forward, it's not clear that Boeing could substitute a Starliner mission for a Crew Dragon mission on short notice if required in any event, because it would require back-to-back Starliner missions.There are only two Starliner capsules, so to support this they would need to refurbish the returning capsule and have it ready to fly again in less than six months, and ULA would need to have the Atlas V ready for it, and presumably this would need to be done on short notice. Consider a launch abort of a Crew Dragon mission: NASA would want to launch Starliner immediately, but that capsule and its LV were not scheduled to be available for another six months. -
#558 by Robotbeat on 20 Sep, 2022 03:20
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That's a lot of words to say, "Yes, now that you mention it, it probably is a viable option to use CFT as an extended mission to ISS if NASA had a real pressing need for it."As I recall, the Crew Demo-2 on Dragon was extended on the ISS and the astronauts even did a space walk. So some precedent has been set.
When NASA thought Starliner would fly before Crew Dragon, they planned an extended CFT for Starliner. The reason is simple: there had been no US crewed spacecraft to ISS since 2011. NASA was paying Roscosmos for seats, and the US side of ISS was understaffed. Extending the CFT mission was logistically simple since there was ample space in ISS. But Crew Dragon flew first, so NASA extended Demo-2 instead of extending Starliner CFT.
They won't extend CFT now, because there is no reason to do so and the logistics are awkward, with contention for space inside the ISS and for docking ports. Also, There had not been a failed Crew Dragon flight prior to Demo-2, while there have been one or (arguably) two failed Starliner missions.
If you think the Demo-2 extension is a precedent using Starliner operationally prior to completion and evaluation of CFT, you might of course be correct, but I don't see it. NASA could do that, but they could also just fly Crew Dragon anyway, or they could just depend on the US astronaut that is still in the ISS due to the Soyuz seat swap to keep the place running, just as they did from 2011 to 2020. I think we are discussing only two potential missions here: replacement of Crew-6 in the Spring of 2023 or Crew-7 in the Fall of 2023. This is such a narrow case that it's not worth speculating about.
Going forward, it's not clear that Boeing could substitute a Starliner mission for a Crew Dragon mission on short notice if required in any event, because it would require back-to-back Starliner missions.There are only two Starliner capsules, so to support this they would need to refurbish the returning capsule and have it ready to fly again in less than six months, and ULA would need to have the Atlas V ready for it, and presumably this would need to be done on short notice. Consider a launch abort of a Crew Dragon mission: NASA would want to launch Starliner immediately, but that capsule and its LV were not scheduled to be available for another six months.
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#559 by deadman1204 on 20 Sep, 2022 13:38
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Why are you so focused on this idea of them extending the CFT? There is no need for it?
That's a lot of words to say, "Yes, now that you mention it, it probably is a viable option to use CFT as an extended mission to ISS if NASA had a real pressing need for it."As I recall, the Crew Demo-2 on Dragon was extended on the ISS and the astronauts even did a space walk. So some precedent has been set.
When NASA thought Starliner would fly before Crew Dragon, they planned an extended CFT for Starliner. The reason is simple: there had been no US crewed spacecraft to ISS since 2011. NASA was paying Roscosmos for seats, and the US side of ISS was understaffed. Extending the CFT mission was logistically simple since there was ample space in ISS. But Crew Dragon flew first, so NASA extended Demo-2 instead of extending Starliner CFT.
They won't extend CFT now, because there is no reason to do so and the logistics are awkward, with contention for space inside the ISS and for docking ports. Also, There had not been a failed Crew Dragon flight prior to Demo-2, while there have been one or (arguably) two failed Starliner missions.
If you think the Demo-2 extension is a precedent using Starliner operationally prior to completion and evaluation of CFT, you might of course be correct, but I don't see it. NASA could do that, but they could also just fly Crew Dragon anyway, or they could just depend on the US astronaut that is still in the ISS due to the Soyuz seat swap to keep the place running, just as they did from 2011 to 2020. I think we are discussing only two potential missions here: replacement of Crew-6 in the Spring of 2023 or Crew-7 in the Fall of 2023. This is such a narrow case that it's not worth speculating about.
Going forward, it's not clear that Boeing could substitute a Starliner mission for a Crew Dragon mission on short notice if required in any event, because it would require back-to-back Starliner missions.There are only two Starliner capsules, so to support this they would need to refurbish the returning capsule and have it ready to fly again in less than six months, and ULA would need to have the Atlas V ready for it, and presumably this would need to be done on short notice. Consider a launch abort of a Crew Dragon mission: NASA would want to launch Starliner immediately, but that capsule and its LV were not scheduled to be available for another six months.
