The experimental goals of ATS-5 included a demonstration using L-band signals to precisely locate ships, tests of an electric ion engine, evaluation of the attenuation effects on RF signals by rain, and C-band communications tests. However, following the firing of the satellite's apogee kick motor, ATS-5 went into an unplanned flat spin. The vehicle recovered and began spinning about the correct axis, but in the direction opposite that planned. As a result, the spacecraft's gravity gradient booms could not be deployed, and some experiments were not functional. The spacecraft was able to perform some of its experimental goals, and was finally boosted above geostationary orbit at the end of its mission. Spacecraft: Aluminum structure, drum mounted solar cells provided 150 W BOL, 2 6 Ah NiCd batteries, N2 and N2H4 thrusters, yo-yo despin, nutation control, solar arrays cooled by heat pipes. Planned as gravity gradient stabilised. Payload: Magnetometer, ion engine (10E-5 lbf resistojet), C-band communications package, millimetre wave propagation experiment, L-band communications experiment.

Design Life: 3 years. Total Length: 1.8 m. Maximum Diameter: 1.4 m. Total Mass: 821 kg.

Applications Technology Satellite; communications tests. Launch vehicle put payload into geosynchronous transfer orbit. Spacecraft maneuvered into geostationary orbit at 108 degrees W. Also tested ion engine.

• 2 - McDowell, Jonathan, The United Nations Registry of Space Objects, Harvard University, 1997. HTML when accessed: http://hea-www.harvard.edu/QEDT/jcm/space/un/un.html
• 6 - JPL Mission and Spacecraft Library, Jet Propulsion Laboratory, 1997. HTML when accessed: http://msl.jpl.nasa.gov/home.html
• 279 - McDowell, Jonathan, Launch Log, October 1998. HTML when accessed: http://hea-www.harvard.edu/~jcm/space/log/launch.html