NASA's Laser Reflector Assembly (LRA) is a passive array of mirrors that provides a target for laser tracking measurements from ground stations. It supports the calibration and validation for the satellite orbit ephemeris that is computed from the Doppler Orbitography by Radiopositioning Integrated on Satellite (DORIS) instrument and Global Positioning System (GPS) tracking measurements, but can also be used to suppose computation of the satellite orbit ephemeris.