NASASpaceFlight.com Forum
General Discussion => Q&A Section => Topic started by: Pipcard on 01/18/2015 02:43 pm
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Why is the PMA black, and what material is that?
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Why is the PMA black, and what material is that?
For thermal consideration and MLI
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I thought MLI was that gold-colored (or silver-colored) foil-like material? It can be black, too?
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See Galileo
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Well it's a Multi-Layer Insulation. The outer color depends simply on what layer is last, as far as I understand.
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So it raises the question : why all orbiting vehicles are not black ?
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Because all vehicles/structures don't have the same thermal requirements
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Isn't there about a 200 degree difference in space from the sun side to the shadow side? In LEO. I know deep space is almost absolute zero. I also know one time a space shuttle in the 1980's couldn't close the cargo doors and has to roll to the shadow side or either to the sun side to get the doors to close before decending.
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Isn't there about a 200 degree difference in space from the sun side to the shadow side? In LEO. I know deep space is almost absolute zero. I also know one time a space shuttle in the 1980's couldn't close the cargo doors and has to roll to the shadow side or either to the sun side to get the doors to close before decending.
That's not how it works. "Space" has no temperature in the common sense, because you cannot measure the thermal state of the vacuum, i.e. nothing. In space, all heat transfer is radiative = is transmitted by electromagnetic wave, mostly infrared.
The temperature on the sun side or on the shadow side does not mean anything by itself. Obviously things will tend to get hotter when illuminated by the Sun and colder when in shadow. But the temperatures achieved depend on the thermal design of your space vehicle/structure.