# It's not air friction that heats space shuttle?

#### bluechipx

I read an article in a science mag. awhile back entitled "The ten misconceptions NASA tour guides hear". They said that air friction is not responsible for the heating of fast moving objects through the atmosphere, but highly compressed air at the leading edges. Now that I am enlightened, could anyone tell me the PSI that the shuttle sees on its nose area? Also the temp? This may be a tough one, but how about the PSI and temp of a meteor entering our atmosphere? Thanks Guys!

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#### redargon

ok, lets say the stagnation pressure is the sum of the dynamic and static pressure at the nose of the shuttle when it's in the tropopause (11000km around 33000ft altitude). The static pressure at this altitude is about 23kPa, the temperature is about -56.5°C and the density of the air is around 0.36kg/m³.

So dynamic pressure is 1/2*density*v²
let's assume the shuttle is doing about 20000km/h (5555m/s) at this point, the stagnation pressure would be 1/2*0.36*5555² + 23000 = 5577444.5Pa = 5.6MPa = 56bar! (812Psi)

this is a very rough approximation, but use it as you like.

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