Body in space

What would happen to a human body that was in space? Let’s say that an astronaut was EVA in regular space suit and somehow got separated from the ship and drifted off into space…and was found hundreds or thousands of years later (assume the body didn’t drift into a planets gravity well or the sun or whatever). What would the condition of the body be in?

Now, how about if the astronaut were in a pressurized space craft that was holed and again drifted off into space, and then was found again hundreds or thousands of years later. What would the condition of the body be in?

I realize there are a lot of variables here (if the suit or space craft were in direct sun light, how far it was from the sun, whether or not anything hit the body or space craft, etc etc)…feel free to make any assumptions you like. I’d say for one assumption, assume the body or space craft wasn’t in direct sun light, or that it was far enough away so that the heat wouldn’t have an effect.

-XT

If the body isn’t in direct sunlight then you start off with a race between two competing factors: The speed of natural decomposition vs. the rate of that latent heat is radiated away.

After a few days or weeks the temperature of the body will drop far enough that it will freeze, stopping further decomposition. Then over the course of weeks or months the suit will gradually lose pressure and any frozen fluids will sublimate off and escape into the vaccuum.

In the long run you’ll get a freeze-dried corpse. How intact it is will depend on how much decomposition occured before it froze.

I’m guessing, but it would be dessicated as it freezes and then the water sublimes away. In fact, it would probably end up like the high altitude South American mummies - freeze-dried by dessication. The body should freeze quickly enough to prevent too much internal decomp and the pressure differential will mean that gas will vent quickly.

Si

How long could such a body remain in that state? Essentially indefinitely (assuming nothing external happened to it)?

-XT

IMHO–Micrometeorite hits would eventually render it unrecognizable as human.

Tens of thousands of years almost certainly. Think of the frozen mammoths dug out of the tundra. That’s a much less stable environment than space and they have been recovered nearly intact.

Wouldn’t bacteria die more or less instantaneously in vacuum, though?

If you’re Discovery astronaut Frank Poole, you can be unfrozen a thousand years later and brought back to life thanks to very advanced medical care: http://en.wikipedia.org/wiki/3001:_The_Final_Odyssey

If the body was under pressure the rot vs freeze would hold true.

But if the ship or suit lost pressure the water in the body would begin to boil off and evaporate. If the pressure drop was rapid the evaporation would be rapid until the body cooled.

If I did that right, the body temperature would approach zero with a relaxation time of about 15 minutes, so rotting would hardly get a chance to start. And water would not boil off very rapidly because the skin holds things together (the scenes in Sci Fi movies where somebody is exposed to vacuum and their eyes explode miss the point that water boiling at body temperature needs very little pressure to constrain and stop it).
Micrometeorites don’t do much over the time scale of decades. Spacecraft that are examined after a few years don’t look any different, and telecommunications satellites see years of service.

I think the body would freeze in hours, and dessicate noticeably in days but would still slowly be loosing measureable water mass for years, and perhaps in a thousand years or so would start looking a little different due to micrometeorites. Over some timescale like that, I think it’d also suffer scissioning of the larger surface molecules by high energy particles and radiation, and the lower molecular weight fragments would evaporate away, so there would be a kind of erosion that would eventually skeletonize it. Any jewelery would be the last remains.

But radiation would probably damage the skin something awful after a significant period of time, right?

I believe some microbes are known to survive exposure to outer space conditions. But they would probably become dormant.