QUESTION:
Is it air-conditioned in the Shuttle?

ANSWER from Jay Buckey:
Yes, it is. The biggest temperature problem on the 
Shuttle is getting rid of all the excess heat produced by the equipment, 
experiments, and people. The inside of the payload bay doors are actually 
radiators that help get rid of this excess heat. If the payload bay doors 
do not open in orbit, the Shuttle has to come home or else it will get too hot.