we do not need spacesuits on eva sometimes

[Findthepin1]

assuming kerbals need the same amount of air pressure to survive as humans, then on kerbin (~0.3-1 atm), laythe (~0.3-0.6 atm), and the lower elevations on duna (~0-0.2 atm, although this needs 0.06 atm or more), kerbals shouldn't need a pressure suit. their space suits should be replaced with something that looks like a scuba diving suit. just a thought.

[mikegarrison]

But that would be work.

I'll settle for the "was a spacesuit really necessary here?" joke and move on.

[Fel]

assuming kerbals need the same amount of air pressure to survive as humans, then on kerbin (~0.3-1 atm), laythe (~0.3-0.6 atm), and the lower elevations on duna (~0-0.2 atm, although this needs 0.06 atm or more), kerbals shouldn't need a pressure suit. their space suits should be replaced with something that looks like a scuba diving suit. just a thought.

Aren't scuba diving suits "pressure suits"?

Besides, the space suit is more than just a pressure suit, it protects against cosmic rays and stuff ;p

How else do you explain kerbals being able to survive in the insane environments we put them in?

[mikegarrison]

I think they use some kind of chlorophyll to directly convert radiation to energy. That's why they don't need life support. And why they are green.

Anyway, I think what the OP was talking about is a mechanical counter-pressure suit.

[KatzOhki]

Aren't scuba diving suits "pressure suits"?

Besides, the space suit is more than just a pressure suit, it protects against cosmic rays and stuff ;p

How else do you explain kerbals being able to survive in the insane environments we put them in?

No, the SCUBA equipment is merely for breathing. The wet suit you typically see is for warmth, some people SCUBA dive without the wet suit. A space suit isolates your entire body from pressure (or lack there of).

[mikegarrison]

some people SCUBA dive without the wet suit

Where the water is warm, yes. Not where I live. In fact, the water is so cold near Seattle that most divers go for a dry suit rather than a wet suit.

[KatzOhki]

Where the water is warm, yes. Not where I live. In fact, the water is so cold near Seattle that most divers go for a dry suit rather than a wet suit.

Yeah. I didn't know if I should mention the difference between a wet suit and a dry suit. Most divers in Southern California where I used to live dive with wet suits from what I've seen.

[Vanamonde]

This suggestion for the game's development has been moved to Suggestions and Development Discussion.

[sumghai]

Findthepin1, you haven't considered the atmospheric composition in your argument just yet.

If Duna is intended to be the Mars analogue, wouldn't its atmosphere contain a non-survivable proportion of Carbon Dioxide (or the Kerbal equivalent)? Also, has it ever been canon that Laythe has a breathable atmosphere similar to Kerbin?

[Findthepin1]

as i explained (see http://forum.kerbalspaceprogram.com/threads/117379-we-do-not-need-spacesuits-on-eva-sometimes), they should have scuba diving-like suits on, for breathing. also, mars' atmosphere is 96% co2, but the atmosphere is on average 0.6% the pressure on earth (see http://en.wikipedia.org/wiki/Atmosphere_of_Mars), which means mars' co2 is only 600 pascals partial pressure. earth's co2 is 400 pascals partial pressure (see http://en.wikipedia.org/wiki/Atmosphere_of_Earth). we can survive up to 2.5 kilopascals without much effect (see http://www.engineeringtoolbox.com/co2-comfort-level-d_1024.html).

[sumghai]

as i explained (see http://forum.kerbalspaceprogram.com/threads/117379-we-do-not-need-spacesuits-on-eva-sometimes), they should have scuba diving-like suits on, for breathing. also, mars' atmosphere is 96% co2, but the atmosphere is on average 0.6% the pressure on earth (see http://en.wikipedia.org/wiki/Atmosphere_of_Mars), which means mars' co2 is only 600 pascals partial pressure. earth's co2 is 400 pascals partial pressure (see http://en.wikipedia.org/wiki/Atmosphere_of_Earth). we can survive up to 2.5 kilopascals without much effect (see http://www.engineeringtoolbox.com/co2-comfort-level-d_1024.html).

What about temperature extremes and Mars/Duna dust storms? I doubt that a heavily-modified scuba suit would provide adequate protection for those (and at that point, you might as well keep the spacesuit anyway, albeit at a lower internal pressure).

[Fel]

No, the SCUBA equipment is merely for breathing. The wet suit you typically see is for warmth, some people SCUBA dive without the wet suit. A space suit isolates your entire body from pressure (or lack there of).

You can't go that deep without a scuba suit though, the body can only take so many atms

What about temperature extremes and Mars/Duna dust storms? I doubt that a heavily-modified scuba suit would provide adequate protection for those (and at that point, you might as well keep the spacesuit anyway, albeit at a lower internal pressure).

I think we're ignoring all the protection the space suit affords outside of supplying positive pressure.

Edited April 29, 2015 by Fel

[Findthepin1]

I think we're ignoring all the protection the space suit affords outside of supplying positive pressure.

we are. temperature is being ignored, but radiation shouldn't be a big problem if you have an atmosphere.

[KatzOhki]

Still, I think he has a point. Some sort of modified, lightweight suit would be appropriate on some bodies with an atmosphere and probably preferred (easier to move around) compared to a full-on space suit. Might be a neat addition to KSP I guess.

[Murph]

You can't go that deep without a scuba suit though, the body can only take so many atms

Not really. For normal SCUBA, the pressure is only a major concern in terms of rate of pressure change, due to decompression issues. The human body can withstand far more than Earth's sea level atmospheric pressure (1 bar). A fully qualified advanced recreational SCUBA diver can go to 50m, which is 6 bar, on just air. With mixed gases, they can go to 80–100m, 9–11 bar pressure (over 10x normal surface pressure). That's all without any form of pressure compensation suit, just a normal wet or dry suit, so the body is fully exposed to the increased ambient pressure. Lack of pressure is a huge problem, but excess pressure is something that the human body copes with remarkably well, as long as it's uniform pressure and matched to the pressure of the gas available to breathe. The breathing gas mixture also has to be appropriate, obviously, as oxygen is toxic at high pressure (compressed normal surface air with 20% O2 is toxic to humans at a bit more than 50m depth, which is why 50m is the traditional normal SCUBA safety limit).

Speaking from personal experience, it's an odd feeling, having 4–5x normal pressure acting in on you, but not at all unpleasant, as long as you manage the pressure changes properly. Throw in feeling weightless, effectively being in an alien environment, and being confident in your training and equipment and dive buddy, and it's a fun activity.

Commercial saturation divers spend weeks on end living at 10x+ atmospheric pressure, when there's a job which calls for it. I'd need to check to be certain, but pretty sure that they can operate down to at least 250m (26 bar / 26x surface pressure) without any form of pressure suit, just a suitable mothership with saturation diving facilities.

If you have seen normal diving dry suits with an air line leading to a valve on the suit, that has nothing to do with pressure compensation, in terms of pressure acting in on the body. It's there for buoyancy control, allowing you to add air to the suit to achieve and maintain neutral buoyancy, with another dump valve to let some air out.

[sumghai]

we are. temperature is being ignored, but radiation shouldn't be a big problem if you have an atmosphere.

The point is, you can't ignore temperature.

Assuming Duna is the Mars analogue of KSP, I'll point out that at night, temperatures on Mars can get as cold as -73~125°C, while the warmest summer's day on Mars is barely 20°C - this is partially due to the distance Mars is from the Sun compared to Earth (Duna is also further from Kerbol than Kerbin). A Kerbal wearing the proposed lightweight scuba suit will freeze to death rather quickly, whereas a proper EVA spacesuit would keep them warm.

The atmosphere on Duna/Mars is very thin, and so does not provide adequate protection against cosmic radiation.

Finally, Martian/Duna regolith may be abrasive enough to wear down / puncture the lightweight scuba suit.