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.
Such damage could occur as a result of an MMOD strike hitting near the docking adapter.
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.