There was a tyre blowout on the first flight which damaged the underside.
Doing some reading the pressure differential between orbit and ground is 4.5% against the internal pressure, far far less than that experienced on touchdown and due to heating during roll-out, and not a significant factor. Similarly the temperature differential is not sign I can't compared to landing and, being inside the vehicle, they don't get exposed to direct sunlight and experience a constant change. As to the temperature they drop to, the problem in space is getting rid of heat, not the cold, and they never go near their lower limits.
https://spaceflight.nasa.gov/shuttle...clss/atcs.html