This document has been declared "Stabilized" and will no longer be subjected to periodic reviews for currency. Users are responsible for verifying references and continued suitability or technical requirements. New technology may exist. A life support system (LSS) is usually defined as a system that provides elements necessary for maintaining human life and health in the state required for performing a prescribed mission. The LSS, depending upon specific design requirements, will provide pressure, temperature, and composition of local atmosphere, food and water. It may or may not collect, dispose, or reprocess wastes such as carbon dioxide, water vapor, uri