Design and development phases of both the Atmosphere Revitalization System (ARS) and the Freon Coolant Loop (FCL) equipment for the Space Shuttle Orbiter are preceded by a requirements definition phase. This phase provides assurance that a reliable, minimum weight and cost-effective system which will meet the needs of the orbiter vehicle and crew will be built.
The paper describes key tasks and accomplishments of the Orbiter ARS and FCL requirements definition phase. Systems approaches used to accommodate the heat loads placed on these subsystems by the vehicle and its payloads, including the European Space Laboratory, are discussed. Total equivalent weight trade studies and preliminary designs conducted lead to the establishment of firm requirements for the detailed design phase.