Vibrations of the Low Power Atmospheric Compensation Experiment satellite

Abstract

The Low Power Atmospheric Compensation (LACE) satellite dynamics experiment has measured vibrations of an orbiting satellite from a ground site and has observed the excitation of satellite vibrations by a sequence of boom movements. The preprogrammed boom movements were initiated by commands from a ground control site and observed by the Massachusetts Institute of Technology Lincoln Laboratory Firepond laser radar facility located in Westford, Massachusetts. In the tests, a narrow-band heterodyne COi laser radar, operating at a wavelength of 10.6 /Ltm, detected vibration-induced differential Doppler signatures of the LACE satellite. Augmentation of vibration amplitudes was achieved through timing of repeated boom movements. Evidence of open-loop vibration damping by this method of repeated boom movements was also obtained, although the data were not conclusive since only a single attempt at open-loop damping was observed. The tests have demonstrated the feasibility and advantages of using relatively low cost ground-based observation techniques for vibration measurements and health monitoring of orbiting structures and for improving the accuracy of mathematical models for the structural dynamics of light, flexible space structures.