Before revision: After the Apollo program, the United States used "a 74-percent oxygen and 26-percent nitrogen breathing mixture" at for Skylab, and a standard air-like cabin atmosphere for the Space Shuttle orbiter and the International Space Station .1 atm
After revision: After the Apollo program, the United States used "a 74-percent oxygen and 26-percent nitrogen breathing mixture" at for Skylab, and a cabin atmosphere of for the Space Shuttle orbiter and the International Space Station .