Search Results

The National Aeronautics and Space Administration (NASA) Space Station Freedom (SSF) will use Flow-Through Radiators (FTRs) to reject waste heat that is collected from the on-board Heat Acquisition Devices (HADs). The waste heat is sent to the FTRs via the Pump Module Assembly (PMA) subsystem of the External Active Thermal Control System (EATCS). Two developmental FTR panels were integrated with the EATCS Ground Test Article (GTA). The integrated components were investigated under a thermal/vacuum environment in Thermal/Vacuum Chamber A at NASA/JSC during June, 1992. A detailed SINDA/FLUINT FTR model was developed to predict the steady-state thermal/hydraulic performance of the FTRs. A simplified SINDA/FLUINT FTR model was also developed for use in the GTA integrated model. Schematics and plots comparing the test data and model results are presented for both steady-state and transient conditions.

This paper presents an overview of the design and operation of the internal thermal control system (ITCS) developed for Space Station Freedom by the NASA-Johnson Space Center and McDonnell Douglas Aerospace to provide cooling for the resource nodes, airlock, and pressurized logistics modules. The ITCS collects, transports, and rejects waste heat from these modules by a dual-loop, single-phase water cooling system. ITCS performance, cooling, and flow rate requirements are presented. An ITCS fluid schematic is shown and an overview of the current baseline system design and its operation is presented. Assembly sequence of the ITCS is explained as its configuration develops from Man Tended Capability (MTC), for which node 2 alone is cooled, to Permanently Manned Capability (PMC) where the airlock, a pressurized logistics module, and node 1 are cooled, in addition to node 2.

This paper presents the integrated approach toward failure detection, isolation, and recovery/reconfiguration to be used for the Space Station Freedom External Active Thermal Control System (EATCS). The on-board and on-ground diagnostic capabilities of the EATCS are discussed. Time and safety critical failures, as well as noncritical failures, and the detection coverage for each provided by existing capabilities are reviewed. The allocation of responsibility between onboard software and ground-based systems, to be shown during ground testing at the Johnson Space Center, is described. Failure isolation capabilities allocated to the ground include some functionality originally found on orbit but moved to the ground to reduce on-board resource requirements. Complex failures requiring the analysis of multiple external variables, such as environmental conditions, heat loads, or station attitude, are also allocated to ground personnel.