The Lunar Orbiter Attitude Control Simulator

Testing the attitude control system of the LUNAR ORBITER was accommplished in an air-bearing facility specifically designed for that purpose. This facility was designed to minimize external disturbances in the platform by seismic motion of the floor, mass deflection of the platform, turbine torques from the air bearing, and thermal currents in the room. The facility was used for the System Design Verification tests. These tests included limit-cycle operation, maneuver sequences, wide-angle Sun acquisition and the star-acquisition (Canopus) sequence. Maneuver angle resolution was to be at least 0.1°±0.1° with the capability of measuring three-axis maneuvers for angles to 80°. The design philosophy as evolved from the experience obtained on company-funded research activities as well as the constraints and approach are presented. Solutions to the facility problem areas, which were predicted or encountered during testing, are detailed. Test results, verifying the solutions to the problems encountered, are discussed. Typical operating characteristics of the simulator during different phases of the LUNAR ORBITER test program are presented