Or would everything just fall back on Soyuz again?
What happens in the event of a loss of mission (not loss of crew) in regards to the commercial crew and ISS programs? (Think: inflight abort)I got to thinking about this because LOM will likely have a much bigger impact on the ISS than it would in the crew program. The crew on station would presumably be approaching the end of the on-orbit life of their vehicle within a few weeks/months. So either a new crew mission has to launch on short notice or a new "life boat" has to be sent up to ISS. Would the provider that faced the LOM have to turn around quickly and attempt a new mission? With no saying of a possible stand down to investigate/repair whatever caused the LOM.Would the alternate provider have to move their next scheduled mission to the left 5-6 months? It seems like a bit of a conundrum because there is consideration of the crew on ISS and their return ship. The commercial crew program would have to provide an alternate flight in some form within maybe 2 months. And the CC providers might have to accelerate their own schedules to maintain proper rotation cadence (of both crew and craft) at the ISS which might have one provider finding themselves with an accelerated mission as well as an unexpected followup 6 months later (and maybe a third...) as the other provider completes return to flight.Or would everything just fall back on Soyuz again?
Quote from: rayleighscatter on 05/13/2017 09:26 pmWhat happens in the event of a loss of mission (not loss of crew) in regards to the commercial crew and ISS programs? (Think: inflight abort)I got to thinking about this because LOM will likely have a much bigger impact on the ISS than it would in the crew program. The crew on station would presumably be approaching the end of the on-orbit life of their vehicle within a few weeks/months. So either a new crew mission has to launch on short notice or a new "life boat" has to be sent up to ISS. Would the provider that faced the LOM have to turn around quickly and attempt a new mission? With no saying of a possible stand down to investigate/repair whatever caused the LOM.Would the alternate provider have to move their next scheduled mission to the left 5-6 months? It seems like a bit of a conundrum because there is consideration of the crew on ISS and their return ship. The commercial crew program would have to provide an alternate flight in some form within maybe 2 months. And the CC providers might have to accelerate their own schedules to maintain proper rotation cadence (of both crew and craft) at the ISS which might have one provider finding themselves with an accelerated mission as well as an unexpected followup 6 months later (and maybe a third...) as the other provider completes return to flight.Or would everything just fall back on Soyuz again? You already gave the answer. Why do you think NASA has TWO commercial crew providers? They are each others back-ups in case one of them has a bad day.
Quote from: woods170 on 05/14/2017 11:19 amQuote from: rayleighscatter on 05/13/2017 09:26 pmWhat happens in the event of a loss of mission (not loss of crew) in regards to the commercial crew and ISS programs? (Think: inflight abort)I got to thinking about this because LOM will likely have a much bigger impact on the ISS than it would in the crew program. The crew on station would presumably be approaching the end of the on-orbit life of their vehicle within a few weeks/months. So either a new crew mission has to launch on short notice or a new "life boat" has to be sent up to ISS. Would the provider that faced the LOM have to turn around quickly and attempt a new mission? With no saying of a possible stand down to investigate/repair whatever caused the LOM.Would the alternate provider have to move their next scheduled mission to the left 5-6 months? It seems like a bit of a conundrum because there is consideration of the crew on ISS and their return ship. The commercial crew program would have to provide an alternate flight in some form within maybe 2 months. And the CC providers might have to accelerate their own schedules to maintain proper rotation cadence (of both crew and craft) at the ISS which might have one provider finding themselves with an accelerated mission as well as an unexpected followup 6 months later (and maybe a third...) as the other provider completes return to flight.Or would everything just fall back on Soyuz again? You already gave the answer. Why do you think NASA has TWO commercial crew providers? They are each others back-ups in case one of them has a bad day.So NASA will encourage (and pay) for the providers to build up a stock of stored LVs? This would also assume that the program can do launch on demand to move flights many months forward. At least at this point flights are being ordered with about 2 years lead time.
Quote from: rayleighscatter on 05/14/2017 02:09 pmQuote from: woods170 on 05/14/2017 11:19 amQuote from: rayleighscatter on 05/13/2017 09:26 pmWhat happens in the event of a loss of mission (not loss of crew) in regards to the commercial crew and ISS programs? (Think: inflight abort)I got to thinking about this because LOM will likely have a much bigger impact on the ISS than it would in the crew program. The crew on station would presumably be approaching the end of the on-orbit life of their vehicle within a few weeks/months. So either a new crew mission has to launch on short notice or a new "life boat" has to be sent up to ISS. Would the provider that faced the LOM have to turn around quickly and attempt a new mission? With no saying of a possible stand down to investigate/repair whatever caused the LOM.Would the alternate provider have to move their next scheduled mission to the left 5-6 months? It seems like a bit of a conundrum because there is consideration of the crew on ISS and their return ship. The commercial crew program would have to provide an alternate flight in some form within maybe 2 months. And the CC providers might have to accelerate their own schedules to maintain proper rotation cadence (of both crew and craft) at the ISS which might have one provider finding themselves with an accelerated mission as well as an unexpected followup 6 months later (and maybe a third...) as the other provider completes return to flight.Or would everything just fall back on Soyuz again? You already gave the answer. Why do you think NASA has TWO commercial crew providers? They are each others back-ups in case one of them has a bad day.So NASA will encourage (and pay) for the providers to build up a stock of stored LVs? This would also assume that the program can do launch on demand to move flights many months forward. At least at this point flights are being ordered with about 2 years lead time.The way you would do it is as follows. Most ISS crew only stay three months on the ISS. CC requires that vechiles have a 6 month life at the station.
Both ULA and SpaceX have good process flows for the launch vehicles but I don't see them as having a stockpile of crew modules as a contingency for LOM, especially if they are not getting paid for that function. My question would be how long it would take to accelerate production on a single source to prevent an interruption in the manned launch schedule.
Which is why you alternate. Space X would go first...have a lom. ULA would go next. As for the average it is being driven up by that one year stay.
And as best as I'm aware, SpaceX can't offer reused boosters for commercial crew.
Quote from: rayleighscatter on 05/14/2017 02:49 pmAnd as best as I'm aware, SpaceX can't offer reused boosters for commercial crew.But if it was an emergency, couldn't they?
Apart from the point I already noted earlier (there is TWO CCP providers for a reason) it is also a fact that there will always be also a Soyuz present at the station AND the station is still perfectly safe even if just manned by a two-person crew for several months. The reason is the halfway swap of Expedition crew members. That is there for a reason. CCP becoming operational will not change that all that much. So, even if a CCP suffers a LOM, there will be no need to de-crew ISS. It will just continue with half a crew until the next CCP flight goes up. And subsequent CCP and Soyuz flight after that can be accelerated to get back into the schedule of halfway crew swaps.
Quote from: woods170 on 05/15/2017 06:25 amApart from the point I already noted earlier (there is TWO CCP providers for a reason) it is also a fact that there will always be also a Soyuz present at the station AND the station is still perfectly safe even if just manned by a two-person crew for several months. The reason is the halfway swap of Expedition crew members. That is there for a reason. CCP becoming operational will not change that all that much. So, even if a CCP suffers a LOM, there will be no need to de-crew ISS. It will just continue with half a crew until the next CCP flight goes up. And subsequent CCP and Soyuz flight after that can be accelerated to get back into the schedule of halfway crew swaps.A CCP suffering a LOM may not be able to reenter. A hull breach or damage to its heat shield may prevent reentry. A damaged docking port may prevent docking. A hull breach where the docking port connects to the main airframe could prevent both reentry and docking. Mission Control's problem is now how to rescue the crew.
Unlike Shuttle, Dragon and Starliner can go up fully autonomously... I guess that doesn't solve a crew rotation problem, but it does highlight that Shuttle isn't good comp here.
Such damage could occur as a result of an MMOD strike hitting near the docking adapter.
Quote from: smfarmer11 on 05/15/2017 01:49 pmSuch damage could occur as a result of an MMOD strike hitting near the docking adapter.Yes and an MMOD strike can hit any spacecraft. Not just the CCP providers.
Quote from: woods170 on 05/15/2017 05:15 pmQuote from: smfarmer11 on 05/15/2017 01:49 pmSuch damage could occur as a result of an MMOD strike hitting near the docking adapter.Yes and an MMOD strike can hit any spacecraft. Not just the CCP providers.True but this is a Commercial Crew thread. Orion is NASA's problem. Each CCP provider needs a solution for its own spacecraft.
Unlike Shuttle, Dragon and Starliner can go up fully autonomously... I guess that doesn't solve a crew rotation problem, but it does highlight that Shuttle isn't a good comp here.
If I recall correctly, Columbia flew with a two crew only on its debut mission.
“The number one safety-related concern for the program is the current situation with respect to the estimate of loss of crew,” Donald McErlean, a former engineering fellow at L-3 Communications and a member of the panel, said at the meeting. “The threshold values were considered to be challenging, and both contractors currently have a challenge to meet that precise number.”
If either or both companies can’t meet the LOC requirement with the spacecraft, NASA may have to issue waivers for that requirement. “That remains a risk to the program that will have to be addressed, in all likelihood, by a risk acceptance waiver,” McErlean said.“It may be necessary to do a formal risk acceptance of the variance from the stipulated goal,” he said later in the meeting. “We would remind NASA that that risk acceptance, including a complete presentation of the alternatives and the consequences, should be made formally, and that risk acceptance signed off by appropriate authorities.”
He (Donald McErlean, a former engineering fellow at L-3 Communications and a member of the ASAP panel) also warned against placing too much emphasis on the LOC metric alone. “One has to be judicious in how one applies these statistical estimates,” he said. “One has to look at whether or not the contractors have expended the necessary effort and engineering activity to make the system as safe as they conceivably can and still perform the mission.” He added that he was ”very positive” both companies were doing so. “There was no known or indicated area where with, by spending even a small amount of money, the contractor could have made their systems considerably safer.” Bill Gerstenmaier, NASA associate administrator for human exploration and operations, has also warned against focusing too much on the LOC statistic alone in weighing risks of flying crewed spacecraft.
From the same article these important take-aways:http://spacenews.com/commercial-crew-vehicles-may-fall-short-of-safety-threshold/Quote from: Jeff FoustHe (Donald McErlean, a former engineering fellow at L-3 Communications and a member of the ASAP panel) also warned against placing too much emphasis on the LOC metric alone. “One has to be judicious in how one applies these statistical estimates,” he said. “One has to look at whether or not the contractors have expended the necessary effort and engineering activity to make the system as safe as they conceivably can and still perform the mission.” He added that he was ”very positive” both companies were doing so. “There was no known or indicated area where with, by spending even a small amount of money, the contractor could have made their systems considerably safer.” Bill Gerstenmaier, NASA associate administrator for human exploration and operations, has also warned against focusing too much on the LOC statistic alone in weighing risks of flying crewed spacecraft.