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The Columbus laboratory module for the International Space Station (ISS) uses active thermal control for cooling of avionics and payload in the pressurized compartment. The Active Thermal Control Subsystem (ATCS) is based on a water loop rejecting waste heat to the Medium Temperature Heat Exchanger and Low Temperature Heat Exchanger on Node 2, part of the US Segment of the ISS. Flow and temperature control in the ATCS is achieved by means of the Water Pump Assembly (WPA) and the 3-Way Modulating Valve (WTMO) units. For the flow control the WPA speed is commanded so that a fixed pressure drop is maintained over the plenum with the avionics and payload branches. Adjusting the WTMO internal flow split permit the two active units to perform the CHX and plenum inlet temperature control. The WPA includes a filter and an accumulator to control the pressure in the ATCS and to compensate for leakage and temperature-dependent volume variations.

Hamilton Standard’s subsidiaries, Microtecnica/Italy and Hamilton Standard Space Systems International/USA, have collaborated to design and fabricate a Water Pump Package (WPP) for the International Space Station (ISS) Multi-Purpose Logistics Module (MPLM). MPLM active payloads (Refrigerator/Freezer Racks (R/FR)) supply cold volume for food and scientific sample storage. The MPLM Active Thermal Control Subsystem (ATCS) maintains specific structural and equipment temperatures for the active payloads. The active thermal control is provided via a low temperature water loop whose flow rate is created by the WPP during MPLM pre-launch and MPLM pre-ISS attach and post-ISS detach mission phases. The WPP also provides compensation for water loop volume variations. This paper will provide a detailed overview of the MPLM Water Pump Package design, as well as providing system performance data.

In the period December 1994 to July 1996 a cryogenic heat exchanger has been developped, by Microtecnica, under a direct contract to ESA/CNES. The heat exchanger has been designed to pre-warm liquid oxygen using HFC-R134a. The main taskswere the trade-off of the thermal path concept, the definition of the structural configuration, the selection of manufacturing methods and the component testing. Two test benches have been realized for the circulation of the oxygen (by AirLiquide) and for the circulation of the HFC-R134a. No mechanical failures or thermodynamic malfunctions have been encountered during all the test campaign. The performances are applicable for fuel cells and manned systems.