Integrated Space Experiment Satellite (ISES) Low Cost Stabilization Subsystem Performance

On June 29, 1991 the ISES satellite was launched into a 450 nm polar orbit. The 183 lbs satellite is a 30 inch diameter, 16 inch high, 16-sided cylinder to provide Nadir-pointing stabilization for a helix antenna associated with the Radiation Experiment (REX) payload of the satellite. The stabilization system uses a 20 ft gravity gradient boom, hysteresis rod damping, a 3-axis magnetometer, a sun sensor and torque coils. Through careful design of the gravity gradient boom and magnetic grooming of the satellite, excellent stability was achieved. The U.S. Air Force commended ISES as the best gravity gradient stabilized satellite. The satellite achieves about 5 degrees pointing error. From the performance of this satellite and potential further improvements that maybe possible, it maybe concluded that gravity gradient stabilization maybe applicable to a wide ranging set of low cost satellite applications.