What is the ambient outside air temperature at the Space Stations mean altitude?
(see also next question, #261(b)) Reply A strange question– and I am not sure the answer will help you with whatever you are really after! The air temperature at an altitude of 250 miles or so may be 700 deg absolute–or more or less, depending on the solar cycle. At sunspot maximum, the Sun emits more soft X-rays, which heat up the upper atmosphere, and which also cause it to expand, increasing the air resistant to low-orbit spacecraft. The space station “Skylab” came down a bit early (1977?) because of increased sunspot activity, and a similar expansion brought down in 1967 the remnants of the artificial radiation belt produced by the “Starfish” nuclear blast in space, in 1962. But that air is very, very rarefied–see http://www.phy6.org/stargaze/StarFAQ5.htm#q98. Where you are sitting, the atmosphere is dense, its molecules constantly collide and share energy, and the temperature is a reasonable indicator of the average energy. Up at 250 miles there hardly remain any collisions (be
