Thermodynamics problem

I dont understand how when the space shuttle exits the earths atmosphere it doesnt burn up. The heat build up would be immense, how does it cool off? Since space is a vaccum, there isnt air to remove the heat, so what fluid takes the heat away? I dont understand how there can be heat transfer without air or some medium to move it.

Space isn't an exact vaccuum... There are still particles around...

I don't think there is a large heat build up when leaving.

The shuttle is still in a LEO (Low Earth Orbit) so there's plenty of cold little atoms to take on heat. But, I don't think anybody believe deep space is a vacuum, there's still stuffin's out there too. It's just a relative vacuum.

Why is there such a difference in heat between taking off and re-entry to our atmosphere?

Heat can leave as radiation (infrared).

We're not going near as fast getting into orbit (and the fastest speeds reaching orbit are at the far end where the atmosphere is rarified) as we are when we come back (and the fastest speeds are pretty meaty atmostphere). Mach 8-10 going up, Mach 20-25 coming in. Energy is proportional to the velocity squared..so that's a lot of difference.

I think I read somewhere that the Silicon tiles covering the skin of the shuttle are designed to re-radiate heat into their surroundings. Isn't thermal radiation just another form of electromagnetic radiation? If this is the case, then it wouldn't need to travel through a medium.

Originally posted by who
Why is there such a difference in heat between taking off and re-entry to our atmosphere?

I think there is a speed difference. Plus I think there is more friction going from nothing to something, than something to nothing. Think of it like sitting in a pool with your arm under water, and then move it out of the water quickly, no bid deal. Now start with it out of the water and bring it down fast into the water, makes a big slap and it hurts.

maybe that is a good analogy maybe not. Someone else might be able to explain it better.