In article , samtkc.afd7a18
@spacebanter.com says...

I hope this question is not too far afield (or too morbid), but does
anyone know what would happen to a dead body after 25 years of drifting
in space inside a spaceship? I am writing a story that includes the
possibility of a astronaut dying while on a mission and his spaceship
drifting for 25 years before it is found. I would appreciate any
suggestions about how a body would decay in this situation.

Depends on the conditions inside the spacecraft. If it vented its
atmosphere, you'd find a dessicated corpse, not a rotten one. If the
vessel still had an atmosphere, some amount of rot would definitely take
place, at least until the available O2 in the atmosphere was used up.
If the spacecraft continued to supply O2 (e.g. it didn't know to stop
doing this), I'd imagine the decomposition to be similar to what you'd
see "on the ground".

Of course, I'm not an expert here. But then again, who is? ;-)

Jeff
--
"the perennial claim that hypersonic airbreathing propulsion would
magically make space launch cheaper is nonsense -- LOX is much cheaper
than advanced airbreathing engines, and so are the tanks to put it in
and the extra thrust to carry it." - Henry Spencer