A software application has been developed for analysis of the International Space Station Thermal Control System for mission operations. This software serves needs unique to spacecraft mission control. Characteristics include multiple vehicle configurations, multiple equipment rack heat loads, complex fluid-loop heat transfer, and integral orbit propagation for radiator performance prediction at any attitude. Object-oriented programming using a C++ class library provides an integrated, interdisciplinary model. Model runtimes are on the order of one minute per day of mission time. Outputs are selected plots, electronic files, and vector displays. Performance and accuracy are verified by comparison with engineering models.