Consider toilet facilties. Folks in space suits wear adult diapers. Apollo missions defecated into plastic bags with the aid of their fellows ("failure was not an option"). International Space Station Freedom FUBAR Space Hole One Alpha has a hugely expensive NASA toilet that, as with all things NASA, would never be used by NASA management. Not ever.
10-21 days without a shower or a toilet, weightless, locked up in a small pod with a bunch of strangers (and possibly some French without even a bidet) is an unpleasant thought. Add a reasonable likelihood of gastrointestinal upset (Montezuma's revenge, New Delhi belly, the trots OTOH and space sickness emesis OTOH). It could be an interminably long, very memorable two to three weeks - especially just after the last plastic bag is filled. Ejected human GI contents evolve gases over time. If you fill, seal, and forget... you will remember.
