Thermal Design of the Instrument for the Transiting Exoplanet Survey Satellite

The thermal design and analysis of space systems is an important application for the field of mechanical engineering. Space systems encounter harsh environments and often have exacting temperature and performance requirements. In this thesis, the thermal design and analysis process undertaken for the Instrument of Transiting Exoplanet Survey Satellite (TESS) is detailed. The TESS program is a two year NASA Explorer mission which uses four cameras to discover exoplanets via the transit photometry method. It will be placed in a high-earth orbit with a period of 13.7 days and will be unaffected by temperature disturbances caused by environmental heating from the Earth. The cameras use their stray-light baffles to passively cool the cameras and in turn the CCDs in order to maintain operational temperatures. It is a payload which encompasses four cameras that have unique thermal requirements which the system was designed to accommodate. These requirements include large power level uncertainty, highly stable temperatures, low temperature CCDs and a compact mechanical design.;The design was matured through analysis using a thermal modeling tool known as Thermal DesktopRTM which uses the finite difference method. A system level model was built with this tool using inputs such as the thermal, thermal-optical properties, the 3D CAD model and thermal contact resistances. It was then used to analyze the system against component temperature limits including NASA specified design margins. Bounding cases have been developed which envelope hot and cold operational cases as well as cold survival during eclipse. Results are presented which show that margins are positive. These design margins provide for contingency in the case of modeling inaccuracies. Later in the program the Instrument will undergo thermal vacuum testing in order to verify the model. Official validation and verification planning is underway and will be performed as the system is built up. It is slated for launch in December 2017.;This material is based upon work supported by the National Aeronautics and Space Administration under Air Force Contract No. FA8721-05-C-0002 and/or FA8702-15-D-0001. Any opinions, findings, conclusions or recommendations expressed in this material are those of the author(s) and do not necessarily reflect the views of the National Aeronautics and Space Administration.