アポロ司令・機械船
In 1965, a pair of altitude chambers were installed in the High Bay for testing the environmental and life support systems of both the Apollo Command/Service Module and Lunar Module at simulated altitudes of up to . Each chamber is high (with a clear working height of ) and an interior diameter of , were human-rated, and capable of reaching the maximum altitude (minimum pressure) in one hour. These were used by the prime and backup crews of all crewed missions, from the ill-fated Apollo 1 in October 1966, through to the Apollo-Soyuz Test Project in July 1975.