Also, at the elevation airplanes fly at, pure oxygen is sufficient for human survival for short periods. At the elevation spaceships travel, pure oxygen isn't sufficient and your blood would boil without a pressure vessel of some sort.
I've read the blood boiling is a myth. Work is being done on flexible spacesuits that aren't airtight and mainly serve to keep the heat in and to keep the astronaut from swelling up. See Space activity suit and BioSuit.
Quote from: mmeijeri on 03/24/2013 08:10 amI've read the blood boiling is a myth. Work is being done on flexible spacesuits that aren't airtight and mainly serve to keep the heat in and to keep the astronaut from swelling up. See Space activity suit and BioSuit. You need to learn the difference between science and nonsense. Skin is not going to maintain any appreciable pressure in the body. Blood will start boiling in a very short time in a vacuum. The dissolved O2 will bubble out first, followed by the liquid itself. What do you think "swelling up" means? It's the gasses bubbling out of blood and tissues and the liquid boiling. Those suits are also nonsense. Keeping the body pressurized by mechanical pressure on the skin isn't remotely practical. There will always be some area that won't have equal pressure being applied by the suit, and you're back to air pressure taking up the slack.
Quote from: Robotbeat on 03/24/2013 04:11 amAlso, at the elevation airplanes fly at, pure oxygen is sufficient for human survival for short periods. At the elevation spaceships travel, pure oxygen isn't sufficient and your blood would boil without a pressure vessel of some sort.I've read the blood boiling is a myth. Work is being done on flexible spacesuits that aren't airtight and mainly serve to keep the heat in and to keep the astronaut from swelling up. See Space activity suit and BioSuit.
Hmm. Tell that to the crew of Soyuz 11.
Shuttle, however, had lots of room and having pressure suits was probably a good idea anyway, since Shuttle started out life needing them (first couple flights had ejection seats, which although of limited value perhaps, needed pressure suits to be developed to be at ALL useful).Just because Shuttle never had a situation where pressure suits during ascent/reentry made a difference between survival and non-survival on any flight doesn't mean it would've never occurred. Shuttle only flew ~150 times.Also, what in case Shuttle had started to lose pressure in the middle of a mission? the crew would've definitely needed pressure suits for the emergency reentry. Which brings up a question: how long to don the ACES suit in an emergency?
Quote from: Robotbeat on 04/02/2013 07:39 pmShuttle, however, had lots of room and having pressure suits was probably a good idea anyway, since Shuttle started out life needing them (first couple flights had ejection seats, which although of limited value perhaps, needed pressure suits to be developed to be at ALL useful).Just because Shuttle never had a situation where pressure suits during ascent/reentry made a difference between survival and non-survival on any flight doesn't mean it would've never occurred. Shuttle only flew ~150 times.Also, what in case Shuttle had started to lose pressure in the middle of a mission? the crew would've definitely needed pressure suits for the emergency reentry. Which brings up a question: how long to don the ACES suit in an emergency?Think about the likely failures and you will see that more often than not the suit doesn't help and in certain cases (e.g., water landing) can hinder your survival. Careful study doesn't really support them and they may only prolong the inevitable. This is VERY much a case of an emotional reaction vice technical.
Again, I think your judgement would be quite different if there had been a western LOC event that involved loss of pressure as a primary cause.
Quote from: Robotbeat on 04/03/2013 02:03 pmAgain, I think your judgement would be quite different if there had been a western LOC event that involved loss of pressure as a primary cause.Would it? Isn't the correct response to design better valves and emergency repress systems? That solves the problem much more directly.IIRC, Shuttle suits were really more about survival after a bailout than in the event of cabin pressure loss. I don't think anyone is planning on bailing out of CST...