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1975 July 24 - .
Landing of Apollo (ASTP) - . Return Crew: Brand; Slayton; Stafford. Nation: USA. Related Persons: Brand; Slayton; Stafford. Program: ASTP. Flight: Apollo (ASTP). Apollo (ASTP) landed at 21:18 GMT, 7.3 km from the recovery ship New Orleans. It was the last splashdown of an American space capsule. However the flight of the last Apollo spacecraft was marred by the fact that the crew almost perished while the capsule was descending under its parachute.
A failure in switchology led the automatic landing sequence to be not armed at the same time the reaction control system was still active. When the Apollo hadn't begun the parachute deployment sequence by 7,000 metres altitude, Brand hit the manual switches for the apex cover and the drogues. The manual deployment of the drogue chutes caused the CM to sway, and the reaction control system thrusters worked vigorously to counteract that motion. When the crew finally armed the automatic ELS 30 seconds later, the thruster action terminated.
During that 30 seconds, the cabin was flooded with a mixture of toxic unignited propellants from the thrusters. Prior to drogue deployment, the cabin pressure relief valve had opened automatically, and in addition to drawing in fresh air it also brought in unwanted gases being expelled from the roll thrusters located about 0.6 meter from the relief valve. Brand manually deployed the main parachutes at about 2,700 meters despite the gas fumes in the cabin.
By the time of splashdown, the crew was nearly unconscious from the fumes, Stafford managed to get an oxygen mask over Brand's face. He then began to come around. When the command module was upright in the water, Stafford opened the vent valve, and with the in-rush of air the remaining fumes disappeared. The crew ended up with a two-week hospital stay in Honolulu. For Slayton, it also meant the discovery of a small lesion on his left lung and an exploratory operation that indicated it was a non-malignant tumour. Additional Details: Landing of Apollo (ASTP).
