Patent ID: 8180505

Claim:
A method for determining the spin axis of a satellite powered by a solar cell, the method comprising the steps of: tilting, by a calibration processor, the solar cell relative to a calibration illuminating beam for illuminating the solar cell at tilt incident angles, measuring, by the calibration processor, characteristics of the solar cell by illuminating the solar cell at the tilt incident angles, the characteristics being indexed to the tilt incident angles, storing, in a lookup table associated with the satellite, the characteristics onboard the satellite, wherein the tilting, the measuring, and the storing are performed prior to launching the satellite into orbit having an initial spin rate and an initial solar incident angle, sensing, by a satellite processor associated with the satellite, voltage and current from the solar cell during an on-orbit rotation of the satellite, determining, by the satellite processor, the characteristics from the sensed voltage and current, and looking up, in the lookup table by the satellite processor, a tilt incident angle indexed to the characteristics, the looked up tilt incident angle being the initial solar incident angle.