NB: The Apollo Command Mudule operated at 5 PSI in spave, about 34% og atmospheric sea level pressure. Over 25,000 feet / 7600 meters elevation. The LM operated at 3.5 PSI.
The Space Shuttle and ISS operate at 14.7 PSI -- normal sea level atmospheric pressure.
Mir, the Soyuz fleet and the Salyut stations were operating at sea level pressure too. I'm not sure how influential that was in the Shuttle's design, but it certainly simplified docking the Shuttle to Mir. The pressure difference between Apollo and Soyuz was a source of complication for the Apollo-Soyuz Test Program.
The Space Shuttle and ISS operate at 14.7 PSI -- normal sea level atmospheric pressure.