I just took the most delightful shower. OK, it was just a navy shower - turn shower on, get wet, turn shower off, suds up, turn shower on, rinse off - but after a week on nothing but baby wipes, it felt fantastic. We're trying to use as little water as possible, because water on Mars will be a scarce and precious resource. The flip side is that water is essential for health, cleanliness and (last but not least) crew morale. One of the main goals of our mission is to find that critical quantity: just enough water, and not a drop more.