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The Space Station Freedom (SSF) Active Thermal Control System (ATCS) “collects, transports, and rejects waste heat from the pressurized elements.” The US Laboratory (USL) ATCS is independent of other SSF elements, and supports all subsystem and payload cooling requirements within the US Laboratory including redundant cooling of life and station critical loads. The thermal transport capability of the USL internal ATCS is sized to accommodate 28.6 kW of waste heat which includes electrical power (25kW), DDCU electrical conversion losses (2.2 kW), DDCU fixed losses (0.2 kW), and crew metabolic loads (1.2 kW). Active control of the coolant flowrate is required to manage the heat rejection capability of the Thermal Control System (TCS). The ATCS accomplishes these functions through pumped, single phase water thermal transport loops which collect waste heat via coldplates and heat exchangers and transport that heat to heat exchangers external to the module.

Life support systems (LSS) will be needed for all manned space missions and include such diverse applications as transportation vehicles, surface habitats, and rovers. Selecting an optimal LSS for a particular mission is the task of life support systems analysis, which must derive parametric values (e.g. power consumption, mass and volume) for the different possible LSS configurations. The task is labor intensive and time consuming, due to the many possible levels of life support system closure, the many available life support technologies, the equally large number of potential mission applications, and the complexity of system interactions. This paper describes TRIALSS (Tool for Rapid and Intelligent Advanced Life support system Selection & Sizing), a tool which makes use of modern software technology to assist in the LSS analysis process. TRIALSS has an icon-driven, user friendly interface which allows the user to select from several physical/chemical LSS technologies.

The International Space Station (ISS) Thermal Control System (TCS) can be categorized into three major subsystems: Passive Thermal Control System (PTCS), External Active Thermal Control System (EATCS), and Internal Active Thermal Control System (IATCS). Each of these segments of TCS is highly automated and as such is very dependent on the on-board software for monitoring and control of the various functions. For the PTCS, software is used to monitor temperature sensor data and command heaters on and off. The active thermal systems contain a large number and a large variety of equipment that is highly dependent on software control. This paper explores the important role that software plays in the operation of the ISS TCS and the need for the hardware and software development to be well integrated. A brief overview is provided of the design and architecture of the three major thermal control subsystems and the related thermal control software.