Of Cats and Astronauts
It seems to be a fairly well-accepted fact that indoor-only cats often experience acute agoraphobia when they get out...sometimes leading to their hiding under the front porch for days on end, not even venturing out for food. It stands to reason that they might go a little batshit; I mean, they eat the same oily mush or pellets every day, and they have to relieve themselves in a tiny sandbox (often with no roof for privacy) that's probably not far enough away for them to escape the smell.
Also, I think the last thing I read about manned spaceflight to Mars said it would take something like a year at the minimum (and that was making some pretty heavy assumptions about our technological and financial will to get there).
So, assuming a handful of astronauts can survive being microwaved (have you heard about the gamma-ray intensity in interplanetary space?) in a tiny tin can, staring at each other day in and day out, eating the same reconstituted crap, and relieving themselves into God-knows-what that probably isn't jettisoned into space too often...what sort of front porch will they go hide under when they get there?