HONEYWELL'S MOMENTUM CONTROL SYSTEM TESTBED

Spacecraft attitude control using Momentum Control Systems (MCS) based on Control Moment Gyroscopes (CMG) or Reaction Wheel Assemblies (RWA) is one of the most difficult things to demonstrate with ground-based hardware. Honeywell has spent the past decade developing and refining a facility for this purpose in Glendale, Arizona. The facility features a surrogate spacecraft weighing approximately 3200 lbs (1450 kg) with first flexible mode of approx. 14 Hz. It includes 6 single-gimbal CMGs (engineering units and flight spares - real CMGs), and both ring-laser and fiber optic 3-axis gyro packages. The spacecraft flies without friction on a spherical air bearing in 3 degrees of freedom, with unlimited rotation about the vertical axis, and +/-30 degrees about any horizontal axis. A unique, proprietary active mass balance system limits the accumulation of momentum in the gravity field to no more than a few Nms. The vehicle carries several hours of onboard battery power, and features a PowerPC-based onboard computer communicating over wireless with a ground station for commands and telemetry. Realtime code is built from MATLAB Simulink and running in minutes. A wall projection system displays STK imagery allowing demonstration of acquisition and tracking of moving targets using an onboard laser and camera. Recognizing the appeal such a facility would have in the space community, a modular design approach was employed, making it readily available to guest investigators - friendly to the plug-and-play of alternative actuators, sensors, and software. The facility has already hosted guests and research programs from both government and industry.