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Old May 3rd 17, 11:05 AM posted to sci.space.policy
Jeff Findley[_6_]
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Posts: 2,307
Default NASA Announces SLS/Orion Flight Slide

In article ,
says...

But on Orion, you claim the crews will need to stay in pressure suits
the whole way?


Do I need to kick you in the ass to dislodge your head, because it
seems to be stuck up there?

Hypothetical: Your spacecraft suffers a decompression incident
halfway to the Moon. What do you do? Remember, this is a vehicle
that has NEVER flow full up and has NEVER flown crewed.

Soyuz suits are good for a bit over two hours. If a Soyuz suffers
decompression they MUST land within that two hours.

ACES is good for 10 minutes. It assumes you're plugged into vehicle
life support systems. Note that Shuttle astronauts didn't wear suits
at all inside the vehicle until after Challenger.

If you didn't have the EVA backpack or an umbillical, the Apollo suits
were good for 30 minutes. The EVA backpack was good for seven hours.


Yes you need to have the suits available in case of a contingency, so
you want to certify them for the longest contingency anticipated (i.e.
depressurization when the capsule is "most of the way" to lunar orbit).

But, even the Apollo 7 press kit said:

https://history.nasa.gov/alsj/a410/A07_PressKit.pdf

Early in the flight, the crew may doff pressure suits and don
the inflight coveralls.

From page 58:

Apollo 7 Spacesuits
Apollo 7 crewmen, for the first hours of flight, and for
the four hours prior to the de-orbit burn, will wear the A7L
pressure garment assembly -- a multi-layer spacesuit coneisting
of a helmet, torso and gloves which can be pressurized independ-
ently of the spacecraft.

So, barring spacewalks and contingencies, the suits were needed about
four hours before luanch ("T-3:45 - Don pressure suits"), during the
first few hours of flight, four hours prior to descent, and then while
they waited for recovery. So, the suits had to work for two
approximately 8 hour stretches. You wouldn't really want to wear an
Apollo suit much more than 8 hours at a time anyway.

Jeff
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