The X4 spacecraft

The X4 (MIRANDA), a technological satellite, and its 3 axis attitude control system are discussed. In addition to the attitude control system the satellite also carries four other experiments: an infrared horizon crossing indicator, a star sensor, a 100-element linear photodiode albedo horizon sensor, and an experiment to determine the behavior of thin solar cells. The satellite is equipped with a lightweight fold-up solar array and multitrack tape recorders. The X4 mission has successfully achieved all its experimental objectives, despite the presence of contamination in the propane gas system which has caused fluctuations in the pressure of the gas supplied to the attitude control jets.