Target Assembly to Check Boresight Alignment of Active Sensors

A compact and portable target assembly (Fig. 1) has been developed to measure the boresite alignment of LRO’s Lunar Orbiter Laser Altimeter (LOLA) instrument at the spacecraft level. The concept for this target assembly has evolved over many years with earlier versions used to test the Mars Observer Laser Altimeter (MOLA), the Geoscience Laser Altimeter System (GLAS), and the Mercury Laser Altimeter (MLA) space-based instruments. These earlier laser altimeters were single ranging channel instruments, but as demonstrated with the five-channel LOLA instrument, the target assembly can simultaneously measure the co-boresite alignment of multiple transmitter laser beams and receiver channels (Fig. 2).