Monday, February 29, 2016

50 Years Ago: The Flight of AS-201

The Saturn 1b clears the tower.
On February 26, 1966, NASA launched the first test of a Saturn 1b rocket carrying the unmanned Block 1 Apollo command and service modules. Block 1 modules were not designed with the forward hatch necessary for docking with the newly-designed Lunar Excursion Module, so they would be relegated to Earth-orbit-only missions. The purpose of this mission was to test the Saturn 1b vehicle integrity, the connections to the CM and SM, rocket guidance and propulsion, and to test the CM on re-entry. This would also include a test of the vehicle recovery plans and ships.
Recovery divers ensure the safe retrieval of the command module.
On the 26th, there was an abort command at four seconds before launch when the fuel tanks in the S-IVb stage fell below expected levels. Quick checking by the engineers and a launch simulation showed that the flight could proceed with the lower pressures, so the countdown resumed and the rocket lifted off from Launch Complex LC-34 at Cape Kennedy. The launch went well, with the Command and Service module separation at 425 miles from the Earth. The SM then fired its engine twice to propel the modules back to the Earth. This proved that the Service module engines could be restarted in space. There were only a few problems with the engine and the control of the CM, mostly dealing with wiring problems and an unexpected leak of helium into the SM fuel.  The command module re-entered the atmosphere and safely made a water landing 37 minutes after launch. The recovery ship USS Boxer found the CM about 70 km from where it was supposed to be. Today the CM is on display to the public at the Strategic Air and Space Museum in Ashland, Nebraska.
USS Boxer (CV-21). USN photo.
Mission patch for flight AS-201.

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