Integrated Active Thermal Control System Analysis of Space Station Freedom Operational Scenarios

This paper describes the integrated active thermal control systems analysis of proposed operational scenarios for Space Station Freedom. The analysis uses detailed mathematical models of Freedom's water, air, and ammonia cooling loops. Also included, is an electrical connectivity model to provide for proper equipment response due to any failure, either electrical or thermal.

The operational scenarios analyzed for this paper are developed by the National Aeronautics and Space Administration in order to provide various disciplines with realistic operational conditions and station construction conditions. The station construction process generates many unique conditions and configurations. During this time, many of the normal system backups are temporarily disabled or reduced in effectiveness. Thermal systems designed for nominal station heat loads must sometimes operate at below minimum design heat loads, and flight orientations unique to early station configurations can cause freezing of cooling loops exposed to the space environment.

This paper describes the analysis of the Mission Build 08 flight. Analyses using base-line assumptions are presented and associated operational problems are discussed. Analyses of proposed workarounds are also provided.