Thermal Micrometeoroid Garment
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An (Integrated) Thermal Micrometeoroid Garment (TMG or ITMG) is the outer layer of a space suit. The TMG has three functions: to insulate the suit occupant and prevent heat loss, to shield the occupant from harmful solar radiation, and to protect the astronaut from micrometeoroids, which could puncture the suit and depressurize it.
The specific design of TMGs varies between different space agencies and different suits, though all serve the same purpose.
[edit] Apollo/Skylab A7L suit
After a Liquid Cooling and Ventilation Garment, pressure bladder, and restraint layer, the TMG for the Apollo/Skylab A7L suit worn on the Moon began with a layer of neoprene-coated nylon ripstop. This was the innermost layer of protection from micrometeoroids. Next, thermal radiation protection was provided by five layers of aluminized Mylar, alternating with four layers of nonwoven Dacron, which provided thermal spacing, followed by two layers of aluminized Kapton film and Beta cloth marquisette laminate. The outermost layer of Teflon-coated filament Beta cloth was non-flammable and provided abrasion protection from the notoriously abrassive lunar dust. This layer was supplemented with Teflon abrasion patches at the knees and other areas.[1]
[edit] Space Shuttle/EMU suit
The construction of the TMG on the EMU suits in use on the Space Shuttle and International Space Station differs somewhat from the construction of the Apollo/Skylab TMG.
The EMU TMG includes seven layers of aluminized Mylar laminated with Dacron, rather than five, and eliminates the use of Kapton. The outermost layer is white Ortho-Fabric, made with a blend of Gore-Tex, Kevlar, and Nomex. This layer can withstand temperatures from -300° to +300° Fahrenheit. The outer layer provides both micrometeoroid and thermal protection, by reflecting most of the sun's harmful thermal radiation.[2]
[edit] References
- ^ Carson, Maurice A.; Rouen, Michael N., Lutz, Charles C., and McBarron, James W. II. Biomedical Results of Apollo - Section VI - Chapter 6 - Extravehicular Mobility Unit. Lyndon B. Johnson Space Center.
- ^ thermal micrometeoroid garment. everything2 (November 13, 2001). Retrieved on 2006-01-07.
| Space suits | ||
|---|---|---|
| American models | Navy Mark V • Gemini Space suit • MOL Space suit • Apollo/Skylab A7L • Extravehicular Mobility Unit • Advanced Crew Escape Suit |  |
| Russian models | ||
| Developing technologies | Mark III • I-Suit • Bio-Suit • Space activity suit | |
| Components |
Hard Upper Torso • Liquid Cooling and Ventilation Garment • Primary Life Support System • Thermal Micrometeoroid Garment
|
|
| Related topics | Extra-vehicular activity • Manned Maneuvering Unit • Pressure suit | |
