Zero Gravity and Life Support Systems — Friends or Foes?

Manned spacecraft life suport systems must operate in a zero gravity environment. Lack of the “pull” of gravity affects heat and mass transfer, fluid transport, phase change, and chemical and electrochemical processes. This paper covers new concepts necessary for humidity control, evaporative coolers, distillation units, and similar equipment required for spacecraft life support. Specific applications used on the Space Shuttle and in development for advanced regenerative systems are discussed, including how they work, how they are tested on earth, and how much, if at all, the weightless environment penalizes the designs.