LACE & RME (USA-51) & (USA-52)

LACE (Low-Power Atmospheric Compensation Experiment), also Losat-L (Low Altitude Satellite)carried visible, infrared and phased sensors to measure distortions in laser beams targeting it from earth.

RME (Relay Mirror Experiment), also Losat-R (Low Altitude Satellite), was one element of an SDI effort to validate the technology needed to perform pointing, tracking, and laser beam relay functions for a ballistic missile defense system. The experiment directed a 1.064-micron laser beam emitted from one ground site to a mirror orbiting at 450 km altitude, and then to a ground-based target. The beam traveled over 1200 km.