Pack for a day trip to mars!

[KrazyHorse]

[QUOTE] Originally posted by Geronimo


this is popular misconception just ask nasa

?

I've already read that. And if you have continued exposure to vacuum, even ignoring the effects of oxygen deprivation, the body gradually (on the order of 5 minutes) suffers massive edema across the entire surface. There is a continued, large pressure differential across the surface of the skin and serious injury is unavoidable.

Mars isn't a vacuum so you could breathe 1KPa oxygen from a tank and safely boost the pressure a bit higher with adustments to a regulator

1kPa oxygen? Gee, thanks, given that the partial pressure of oxygen at the earth's surface is 20kPa and hypoxia follows quickly if the pp falls below 8 kPa or so.

[KrazyHorse]

Listen: the human body, to continue functioning at anything other than the lowest level, requires a partial pressure of O2 in the lungs of ~15kPa. There will be serious injury almost immediately if such a pressure is maintained inside the lungs while the exterior pressure is on the order of 1kPa. According to a rough estimate it would be like trying to breathe with a 300kg weight pulling outward on your chest.

Good luck with that. I'll take my hamster ball any day of the week.

[KrazyHorse]

Would probably rip the diaphragm too.

[Spiffor]

BTW, while we're at daydreaming about Mars, would it be theoritically possible to engineer a lifeform that could survive the pressure and the cold, while feeding off whatever the atmosphere/soil provides?

[molly bloom]

Originally posted by KrazyHorse
Would probably rip the diaphragm too.

Thoughtful of you to consider contraception.

[KrazyHorse]

Originally posted by Spiffor
BTW, while we're at daydreaming about Mars, would it be theoritically possible to engineer a lifeform that could survive the pressure and the cold, while feeding off whatever the atmosphere/soil provides?

possibly.

I would think that the best bet would be a photosynthetic single-celled organism of some kind (think super-algae).

[molly bloom]

Originally posted by KrazyHorse



I would think that the best bet would be a photosynthetic single-celled organism of some kind (think super-algae).

You need to stop hanging around bars frequented by American Repugs.

[Spiffor]

I have just looked for info about artificial ecosystems (close systems, mind you, not terraformation attempts), and they're surprisingly advenced already. The current MELISSA project of the ESA has an efficiency of about 70%, and a subpart of it, the BIORAT (which only focuses at recycling air) is ready for micro-gravity testing.

While these artificial ecosystems may bring many good things in the civilian area, they are precisely done for Space exploration, especially for a manned mission to Mars that the space agencies believe not to be too far in the future

[Geronimo]

Originally posted by Chemical Ollie
If you are stationed on a sub (I read between the lines that you are), understanding P and kPa is essential. Most subs will be squezed if P gets above 3000 kPa or something.

P is pressure and kPa is the unit it's measured in. Atmospheric pressure at sea level is 100 kPa. Every 10 meters you dive in water adds 1 atmosphere = 100 kPa to the pressure. If I recall right, a modern sub can dive to 300 meters where the pressure is 3000 kPa (I know some can dive deeper, just an example).

not everybody uses kPa to measure pressure. I'm more used to thinking of pressure in mm Hg

[Geronimo]

Originally posted by Spiffor

I think the reason why they're not thinking outside the box is pressure indeed.

If you often scuba-dive, I take it you have the habit of stopping your swim-up at regular intervals (so that your lungs can progressively adapt to the new, lower pressure without exploding).
The differences of pressure between deep water and surface are enough to kill you if you don't go progressively enough. And yet, the difference of pressure is faaar inferior to the difference between Earth and Mars. If you get out of a pressurized vehicle and were confront to Mars's tiny pressure, you'd die as surely as if you swam up from the most extremes depths of sea to the durface in one second.

If you don't wish to play the bubble-man on Mars, maybe the "outside the box" possibility would be to use your monthes-long trip to progressively adapt the cabin pressure to 1 kPa (Mars's pressure). But I absolutely don't know if the human body could live under this pressure at all, regardless of the transition time.

whoah the difference isn't "faaar" greater. You don't have to dive all that deep to add 1 atmosphere of pressure.

Every 10 meters you dive adds one atmosphere.

[Spiffor]

Well, I'm not an adept of Scuba diving, but I didn't know the divers were used to diving at 1km depth

[Geronimo]

Originally posted by KrazyHorse
Listen: the human body, to continue functioning at anything other than the lowest level, requires a partial pressure of O2 in the lungs of ~15kPa. There will be serious injury almost immediately if such a pressure is maintained inside the lungs while the exterior pressure is on the order of 1kPa. According to a rough estimate it would be like trying to breathe with a 300kg weight pulling outward on your chest.

Good luck with that. I'll take my hamster ball any day of the week.

You're underestimating the durability of the lungs. The minimum pressure difference required to risk pulmonary barotrauma is about 80 mm Hg .

the 300kg weight analogy doesn't seem right either. The pressure difference experienced by the aorta for example is on the order of 18 kPa and it's hard to imagine it would be equiped to hold back a 300kg weight.

[Geronimo]

Originally posted by Spiffor
Well, I'm not an adept of Scuba diving, but I didn't know the divers were used to diving at 1km depth

1km? where did that come from?

[Spiffor]

Originally posted by Geronimo
1km? where did that come from?

If 10m = 1 extra atm of pressure, you need 1km to have 100 atm of pressure. Which is the difference in magnitude between Earth's and Mars' atmospheres.

[Geronimo]

Originally posted by Spiffor

If 10m = 1 extra atm of pressure, you need 1km to have 100 atm of pressure. Which is the difference in magnitude between Earth's and Mars' atmospheres.

spiff think twice about that. The difference between earths atmospheric pressure at sea level and a total vacuum will be just one atmosphere. So how could the difference between earth and mars atmosphere be equivalent to a difference of 100 atmospheres?

For physiological considerations it will be absolute change in pressure not relative changes in pressure that are going to matter.