A Thermal control system is a necessary component in ensuring survival of the Space Station Freedom (SSF). The hostile space environment can produce surface temperatures from +250°F to −250°F depending upon orbital conditions, thermal control coatings and geometric configuration. The Passive Thermal Control System (PTCS) is required to maintain the interior surfaces above 62°F to prevent condensation and below 113°F to protect the crew.The Passive Thermal Control System includes multilayer insulaton (MLI), thermal control coatings (TCC), electric heaters, thermal isolators, and plumbing insulation. Electrical heaters or thermal isolators are required to prevent condensation at module locations where penetrations occur in the MLI or surfaces with significant exposure such as cupolas. Examples of these penetrations are windows, meteoroid/debris shield support structure, berthing mechanism area, trunnion/keel support structure, grappling fixture attachment, and plumbing lines.Studies and development tests are planned to provide a state of the art Passive Thermal Control System to meet the requirements as closely as possible. These tests will include demonstration of MLI attachment concepts, thermal vacuum performance evaluation, and thermal control coating exposure and performance tests.