Author Topic: Crew Dragon Mission Life Extension: Free-Flying, Uncrewed Duration  (Read 14090 times)

Online TheRadicalModerate

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AIUI, the suits are definitely not meant for EVA. They got no heat or cooling.

Yeah, but the the umbilicals provide temperature-controlled air.  It isn't perfect, but it's better than nothing.

I'm more worried about dexterity in vacuum.

Quote
If a patch can be put on from the inside that's a plus. D2 pressure holds it in place. On the outside the pressure wants to blow it off.

Of course the hole will be inaccessible from the inside. Kinda like dropped toast always hits butter side down.

Yup.  It may be better just to assume that the only two responses are:

1) Wait for a new D2.

2) Climb in, use the umbilicals, and do an expedited de-orbit.  Of course, given that you have some piece of MMOD that went through the pressure vessel, you'd really like to do an extensive checkout before de-orbit, but you're on a clock.  There has to be enough nitrox to cool the cabin during reentry, MMOD hole or not.

Offline OTV Booster

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AIUI, the suits are definitely not meant for EVA. They got no heat or cooling.

Yeah, but the the umbilicals provide temperature-controlled air.  It isn't perfect, but it's better than nothing.

I'm more worried about dexterity in vacuum.

Quote
If a patch can be put on from the inside that's a plus. D2 pressure holds it in place. On the outside the pressure wants to blow it off.

Of course the hole will be inaccessible from the inside. Kinda like dropped toast always hits butter side down.

Yup.  It may be better just to assume that the only two responses are:

1) Wait for a new D2.

2) Climb in, use the umbilicals, and do an expedited de-orbit.  Of course, given that you have some piece of MMOD that went through the pressure vessel, you'd really like to do an extensive checkout before de-orbit, but you're on a clock.  There has to be enough nitrox to cool the cabin during reentry, MMOD hole or not.
Once they step out it's ~120C in the sun and ~100C ~-100C in the shade. I'd give them 10 minutes max on a Hail Mary EVA, probably less. Where is the hole? Where are the non-existent hand holds? Can they even assume the position and kiss it goodby in a suit?
« Last Edit: 10/23/2023 12:49 am by OTV Booster »
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Offline DanClemmensen

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AIUI, the suits are definitely not meant for EVA. They got no heat or cooling.

Yeah, but the the umbilicals provide temperature-controlled air.  It isn't perfect, but it's better than nothing.

I'm more worried about dexterity in vacuum.

Quote
If a patch can be put on from the inside that's a plus. D2 pressure holds it in place. On the outside the pressure wants to blow it off.

Of course the hole will be inaccessible from the inside. Kinda like dropped toast always hits butter side down.

Yup.  It may be better just to assume that the only two responses are:

1) Wait for a new D2.

2) Climb in, use the umbilicals, and do an expedited de-orbit.  Of course, given that you have some piece of MMOD that went through the pressure vessel, you'd really like to do an extensive checkout before de-orbit, but you're on a clock.  There has to be enough nitrox to cool the cabin during reentry, MMOD hole or not.
Once they step out it's ~120C in the sun and ~100C in the shade. I'd give them 10 minutes max on a Hail Mary EVA, probably less. Where is the hole? Where are the non-existent hand holds? Can they even assume the position and kiss it goodby in a suit?
There are two justification for having active-only IDSS ports on Crew Dragon today:
    1)The passive components add mass that can better be used for a bit of extra cargo.
    2)There is currently no realistic mission where Dragon-to-Dragon docking is useful because Dragons cannot survive long enough for a rescue to work.

But this is the "Mission Life Extension" thread. If Dragon can in fact loiter longer, then converting the active-only port into an active-passive port makes sense, and the Dragons can dock to each other.

Online TheRadicalModerate

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There are two justification for having active-only IDSS ports on Crew Dragon today:
    1)The passive components add mass that can better be used for a bit of extra cargo.
    2)There is currently no realistic mission where Dragon-to-Dragon docking is useful because Dragons cannot survive long enough for a rescue to work.

But this is the "Mission Life Extension" thread. If Dragon can in fact loiter longer, then converting the active-only port into an active-passive port makes sense, and the Dragons can dock to each other.

Even in the case where a D2 goes bad loitering on orbit, the replacement would likely dock with the OTV-LSS, not the other D2.  There are cases where both OTV-LSS and HLS-LSS are passive-only (e.g., in the case where they're only going to be doing crew transfers at Gateway), but my guess is that OTV-LSS (and HLS-LSS, for that matter), will be active-passive.

Offline DanClemmensen

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There are two justification for having active-only IDSS ports on Crew Dragon today:
    1)The passive components add mass that can better be used for a bit of extra cargo.
    2)There is currently no realistic mission where Dragon-to-Dragon docking is useful because Dragons cannot survive long enough for a rescue to work.

But this is the "Mission Life Extension" thread. If Dragon can in fact loiter longer, then converting the active-only port into an active-passive port makes sense, and the Dragons can dock to each other.

Even in the case where a D2 goes bad loitering on orbit, the replacement would likely dock with the OTV-LSS, not the other D2.  There are cases where both OTV-LSS and HLS-LSS are passive-only (e.g., in the case where they're only going to be doing crew transfers at Gateway), but my guess is that OTV-LSS (and HLS-LSS, for that matter), will be active-passive.
In general there is no reason for long duration D2 when it has something to dock to. The thread is generic not just for support of the SLS/Orion replacement scheme. I was thinking about free-flying long-duration missions.

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