Atros
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Joined: 6/26/2020
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ORIGINAL: MatthewVilter
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ORIGINAL: Atros
Yeah, those kinds of suits are the common item in any respectable SciFi, but there comes certain problems with those. First is the fact that anything skin-tight enough to block air from moving is hard and slow to suit up.
There should be some method of adjusting tension. Anything from pressure tubing to memory alloy to MEMS winches on each elastic fiber.
It is possible there might be ways, but not in near foreseeable future to my knowledge, which would definitely make producing them a problem in devastated newly low-tech world.
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ORIGINAL: MatthewVilter
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Second is the fact that air being one of best insulators of heat means that suit that is fit to skin usually isn't very warm, especially in near absolute-zero temperatures, which would need active heating, which needs energy, which would create requirements for long term usage regardless of the energy source (short of miniature nuclear battery, which would probably need an exoskeleton to move in itself).
Vacuum is a better insulator than air so unless you're in a hot environment and need insulation for heat shielding the bigger worry is dumping the wearers body heat which can actually be achieved by letting the wearer's sweat sublimate into vacuum (maybe not a great idea if water is a scarce resource).
Vacuum is better insulator, true, but you probably don't want that vacuum to touch your skin. I haven't read or heard enough about human experiments in exposing them to vacuum, but there is quite high probability of something similar than osmosis happening there. Thus you would need second layer in between to apply vacuum, which would mean thicker suit... And yet there is no such thing as perfect insulation.
The sweating would be easy easy to handle, simply allow there to be water absorbent material layer first that conducts the water away from the body, keeping the heat in would be the tricky part. Heat like any energy can transfer by three ways, conduction, convection and radiation and radiation can move even in the vacuum and conduction happens as long as two even slightly conducting layers even slightly touch each other. What makes heat worse to insulate is its tendency to change transfer from one to another in the run and thus even the vacuum wouldn't have complete insulation.
I start to believe your theory the same day as there starts to drop fashionable, less than centimetre thick winter clothes that can withstand even -30 decrees celsius winter temperatures in my country and see that those polar expedition people seems like anything but stuffed bears when they are doing anything in the polar areas.
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ORIGINAL: MatthewVilter
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Third notice is that when you look at the shoes in those pictures, including the one in "The Martian", there doesn't seem to be any airtight seal next to the boots and even if the suit would be airtight against the skin, you don't need to be a nuclear scientist to know that skin-exposure to air or other medium with temperature under -50 C¤ for more than few short moments is a bad idea.
I don't know what the stocking/foot covering parts of these suits would look like exactly but I'm pretty sure the hiking boots go on or are built over the pressure suit.
So your asstronauts run around in baby clothes eh?
(The pictures had separate clearly footwear, so I am assuming we are not talking about the current type overall-included astronaut boots, hey it was you who wanted to start talk about astro-fashion)
That would work for the air insulation, but those Mike's you are wearing (you know, pirated Nike's) would need to be quite many sizes larger to offset all the insulation needed to the included sock-part of the overall. Also if the insulation is in the sock, it would probably need to be double thickness compared to the rest of the suit, as it would besides the insulating layers also have material that keeps the insulation intact in gravity environment, as the body weight has a tendency to squeeze anything under it. Usually that is why the boot is included into the spacesuit and that is why external boots would almost certainly have some kind of lock to lock them in place and avoid the need to include the insulation inside into the overall under.
Besides non-locked separate boots would create the problem of small rocks going inside them and eating away that sock part anyways and thus it would need to be made sturdy to not break like cotton socks in a long hike with rock on your boot. This naturally doesn't even take into account the fact that extra slits in an environment like Moon or Mars where there could be buildup of irradiated dust would probably be bad idea for your long term health.
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ORIGINAL: MatthewVilter
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There probably is a reason that only the suits used inside spacecraft are even close to something similar...
Yeah honestly I think there are probably a lot of difficult problems with them. The neck air dam and gloves seem like particularly tricky bits to me. But as I was getting at earlier I see space suits as something that we are many decades behind the curve on. It doesn't bother me at all to hand wave a lot of the necessary engineering/tailoring innovations because I see it as a relatively uncharted design space and the laws of physics don't seem like a particularly aggressive opponent in this case.
In this case, there probably are two approaches, either they are made the traditional way and there are placed hard materials for locking them in place and they look less fashionable or there is a mechanism that self-insulates it against the material, which probably would provide high risk of critical material failure. The reason we use 70's tech now still in space is because it has been proven to work reliably in every scenario and thus I am having hard time to see some world shattering changes in the design without some unobtainium-material that actually melds and unmelds with other materials on the fly.
Anyways I wouldn't held my breath to ever see some Jetsons-style space suits in real use outside SciFi.
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RE: Some questions regarding hostile planets - 
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