Abstract: Spacecraft maneuvers (e.g., orbit transferring, stationkeeping and attitude controlling) of a first spacecraft are realized with conventional force and torque generators (e.g., thrusters and momentum wheels). Spacecraft maneuvers of a second spacecraft are realized through magnetic interaction between the first and second spacecraft. In particular, a magnetic moment vector m.sub.1 of a magnetic system of the first spacecraft and a magnetic moment vector m.sub.2 of a magnetic system of the second spacecraft are adjusted to apply selected force vectors and torque vectors to the first and second spacecraft.

Abstract: An imaging system is attached to a satellite, the imaging system includes a transmitting segment which transmits a field of view of photonic radiation to a focal plane array imager. Displacements such as jitter and drift are capable of being applied to the imaging system, which can result in apparent movement of said field of view applied to the focal plane array imager. A stabilizing segment limits the apparent movement of the field of view detected by said focal plane array imager in two orthogonal sensed translational directions, and about a sensed rotary direction.

Abstract: A surveying satellite apparatus having an on-board microprocessor to process sensor-provided data from planetary and/or celestial reference scene. The sensor data is compared with the on-board spacecraft database to determine if any misorientation or translation error is present. The spacecraft attitude and ephemeris solutions are autonomously updated to reflect the realtime alignment.

Abstract: A system for surveying features of a planet includes a novel attitude determination subsystem. A satellite includes an earth imaging sensor (106). The sensor is alternately directed at the earth and a predetermined star field. The optical detections are converted to electronic signals by a sensor electronics module (332). The outputs of the sensor electronics module corresponding to the times when the sensor is directed toward earth are processed by a signal processor (336), the output of which is a data stream which permits image reconstruction by a ground station computer. The outputs of the sensor electronics module corresponding to the times when the sensor is directed toward the star field are directed through onboard star detection thresholding electronics. A programmable threshold device (342) selects detections of target stars within the star field. A star data buffer (344) stores these target star detections for transmission to earth at a convenient time.