What is an astronaut's maximum absorbency garment?

A pressure suit is a sealed system. Once a crew member is inside it and the gloves and helmet are locked, there is no route to a toilet for as long as the operation lasts, and a spacewalk routinely occupies most of a working day once pre-breathe and airlock time are counted. The Maximum Absorbency Garment solves that in the least glamorous way available: the wearer relieves themselves inside the suit, and the garment holds the result.

The MAG is a close-fitting brief filled with sodium polyacrylate, the same superabsorbent polymer used in infant nappies, which binds many times its own mass of liquid into a stable gel. That property is what makes it usable in weightlessness, where free liquid does not stay where it is put. Gelled urine cannot migrate, pool against the skin or drift into the water-cooled undergarment and the suit's electrical connectors, where it would be a genuine hazard rather than a nuisance. A fresh garment is normally donned for each phase.

Apollo crews used a roll-on cuff feeding a urine collection device, plus a faecal containment bag that nobody remembers fondly; the whole design assumed male crews. When the Shuttle era brought women into the astronaut corps, a containment trunk and then the MAG replaced that arrangement with something unisex that worked for both kinds of need. The garment is also worn strapped into a seat during launch and entry, phases where a crew can spend hours suited with no realistic alternative.