Apollo AS-203

Description

The Apollo/Saturn AS-203 mission was an unmanned test of the S-IVB (second stage) and the Iu (instrument unit) of the Saturn V to obtain flight information under orbital conditions. The configuration of the Saturn IB was made to match the Saturn V as closely as possible. The two-stage launch vehicle boosted a payload consisting of the S-IVB, Iu, and a nose cone into a 188 km circular orbit with a period of 88.21 minutes and an inclination of 31.94 degrees. The S-IVB engine burned once in the Earth's atmosphere and then was shut down. The engine's capability to restart after coast was demonstrated. Flight information was obtained on venting and chill down systems, attitude and guidance control, thermal control, and performance of the propellant tanks. Two cameras were mounted to take photos to record the behavior of the liquid hydrogen fuel in the tanks. One of the cameras failed before launch, the other transmitted images to Earth. During the fourth orbit internal pressures built up in the S-IVB stage while a pressure differential test was being performed. The pressures built up well in excess of design values and the stage fragmented. However, all mission objectives were achieved.