I tried it too, all links worked for me, but it is specifically about the Mars part. Not that it matters, they'll have to pee/whatever on their way there too... but the question form pops up an Outlook email from me, so I can't try it here (at work) but I'll try later when I get home.

This issue is brought up a lot by Larry Niven. Will try to ask him, too, or Jerry Pournelle, or anyone who writes well-researched SciFi.