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Cake day: 2024年2月28日

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  • If the Boe-CFT mission had gone to plan, Crew-9 would have been scheduled to launch in mid August with Zena Cardman commanding. The article reports that she has just announced that her father died in August, perhaps about a week before what would have been the launch date.

    Got me wondering how situations like that are handled. And what if a close family member dies just a day or two before launch? Or even less time than that?

    On a related matter, I’ve also been wondering at what point the backup crews are ‘stood down’. I don’t think it’s the very last minute. I think there’s a window of time during which any serious issues to do with a member of a primary crew would just result in a scheduled launch not going ahead (as opposed to going ahead on schedule but with a crew member swapped out).



  • Scenario 4

    Well, consider various lesser versions of Scenario 1. What if the crew was only partially reduced in their capabilities?

    Perhaps they were both suffering from the symptoms of carbon monoxide poisoning (including headaches, dizziness, and confusion). Or perhaps one was serously injured, and the other was fine but needed to focus all her attention on tending to her crewmate?

    Then it would come down to the question of just how complex and time-consuming the required manual step(s) are. If there’s just a big red button that says “TAKE US HOME” then, it shouldn’t be a problem. But we don’t know.

    And if there was just a big red button, couldn’t they try bypassing the current 4-week delay, by coming up with some ways of pressing it without humans on board? ;) Shove an astrobee in there and give it a try. If it doesn’t work, no harm done …


  • Aren’t there several realistic scenarios …

    Scenario 1

    Emergency on board ISS. 1) One aspect of the emergency (e.g. noxious air) has incapacitated many of the crew, including all the ones trained to operate Starliner. 2) Another aspect of the problem (e.g. electrical faults that are expected to lead to fire) leaves no doubt that evacuation is essential.

    Those ISS crew who managed to don emergency breathing apparatus quickly enough now move the incapacitated Starliner crew to their seats, strap them in and exit Starliner (closing the hatches on their way out), before proceeding to their own vehicle(s).

    Scenario 2

    Serious MMOD strike upon a docked vehicle, causing damage that makes it very unlikely to be safe for its crew to return in, and also at significant risk of posing a danger to the ISS.

    Wouldn’t the least bad option be to command an uncrewed undocking and hope for the best?

    Scenario 3

    During a flight test, a spacecraft is able to dock with ISS, but only after encountering significant problems. The first job of engineers is to consider whether it is sufficiently safe for the crew to return to Earth in, in the event of an emergency. Their decision is either ‘no’, or ‘barely’.

    An alternative provider of crewed LEO access services, known for its proficiency and speed of operations, announces that they will be able ready to send a replacement vehicle by the time of a suitable launch opportunity in 4 days’ time.

    There are no spare docking ports.



  • In the implication here that it is Congress who want a diversity of suppliers, whereas NASA doesn’t care as much?

    Yes, I think that’s the implication. I realized it’s not correct but decided to leave it like that. I’m a big picture kinda guy; someone else can sort out the details!

    I guess it might be more like a combined NASA / Space Force high level strategic fund providing the subsidy. So that individual ‘low level’ programmes within NASA / Space Force then don’t have to worry too much about the long term strategic goals like dissimilar redundancy, and can mostly just focus on their own needs.



  • the most likely alternative would be to bring the astronauts back using SpaceX’s Crew Dragon by removing two astronauts from the Crew-9 mission

    The most likely? Not convinced. Wouldn’t anyone removed from Crew-9 just be shifted to Crew-10? So it’d seem silly to announce Crew-10 only to have to change it a week later.

    And even if they don’t care about looking silly in that way, they might instead just go with one empty seat ‘uphill’ for each of Crew 9 and 10. Because that’s a less drastic change to make to Crew 9 at such short notice.

    But maybe I’m wrong. So, assuming the quoted scenario actually is what happens …

    I guess they’d have to keep the Russian (Gorbunov)?

    And keep the capsule commander (Cardman)? But she’s never been to space, so maybe the pilot (Hague)? I can’t immediately see if he was expected to be the ISS commander, but if so, I guess that would give them a good excuse to ‘promote’ him over Cardman?

    Wilson has had more launches than Hague (3 versus 2ish) but a lot less time in space, and I don’t know if she would be as well trained for Dragon as the commander & pilot.



  • Turns out that some of the later parts of the video I posted largely negated my above comment.

    What do you think will happen to the other one? Do you think they’ll maintain a Florida splashdown capability indefinitely, as a backup

    Question at 43:08.

    43:56 “There may be a small transition period as we’re moving vessels through the Panama Canal … where we can support either Coast …” (implying not indefinite)

    e.g. in case of bad weather in all the new West Coast splashdown zones

    51:15 “one benefit of moving to the West Coast is much better weather”

    Also of interest …

    30:39. Sounds like they didn’t bother with a Public Safety Determination in the end, and just went directly to full(?) approval.



  • Only yesterday I was here objecting to large expenditures on debris mitigation (specifically, to the “US De-Orbit Vehicle” for the ISS), so I guess I’d better be consistent (regardless of down-votes)!

    If I was advising SpaceX, I’d tell them to go with this West Coast plan.

    If I was advising humanity as a whole, I’d point out that despite our evolved psychology as a species, we are sometimes still capable of behaving rationally. And if the expected value of any particular iniative to make some space industry debris less likely to do harm to people/property is less than the actual cost of that initiative, it probably shouldn’t go ahead.

    Also, I’d be interested to see how this changes the Loss of Crew probability. Presumably it’s less risky to do trunk separation prior to the deorbit burn, because if the separation process encounters any problems, there is much more of an opportunity for troubleshooting.


  • We’ll move a Dragon recovery vessel to the Pacific some time next year

    What do you think will happen to the other one? Do you think they’ll maintain a Florida splashdown capability indefinitely, as a backup (e.g. in case of bad weather in all the new West Coast splashdown zones)?

    Or just keep it going for a while, until they’re happy with the new arrangements? Would they then decommission the other recovery vessel? (There are just two of them, right?) Or move it to the West Coast to join its sister?






  • Uncontrolled re-entry of a single large object would, I think, be preferable to re-entry of dozens of them.

    I guess the opposite. It won’t be a single object for long, after the final re-entry has started, so I say give the breakup process a headstart! (Well, I don’t actually. I actually assume it’s a bad idea, and would like to know why. Geopolitics not included.)

    No agreement would have any effect on the headlines saying “US allows its spacestation to crash on city, killing 800 people”.

    Agreed. However, I’d bet my life that this wouldn’t happen. Both literally (though I’d need good odds, and a high valuation for the value of my life!), and in the sense that I (and all my loved ones) live under the ISS’s flight path.

    I estimate (partly based on this) that less than 0.6% of the earth’s surface is “built-up”. (Though the ISS doesn’t fly over it all equally, so call it 1%.)

    For what it’s worth (nothing?!), I used that figure, and some other guessed figures, to guess that the expected value of the number of people killed per uncontrolled ISS reentry is 0.05, so on average needing 20 space stations to kill 1 person.