The Thermal Micrometeoroid Garment (TMG) is the outer portion of the Extravehicular Mobility Unit (EMU). The TMG minimizes the amount of heat transfer between an astronaut and the space environment, and provides protection from micrometeoroids. Multilayer insulation separates the outer surface of the TMG from the inner surface and crewperson. The performance of the present TMG insulation may be a contributing factor to the cold discomfort experienced by the astronauts.
The TMG Thermal Performance Study tested combinations of insulation materials based on thermal conditions, total heat transfer, and insulation properties. The results from this study will be used to support design refinements for future developments of an extravehicular mobility unit.