The Mars Observer Laser Altimeter, developed for flight on the Mars Ob
server spacecraft payload in September 1992, is designed to measure th
e topography of the Martian surface over a 2-year period from a 400-km
mapping orbit. A 40 mJ pulse diode-pumped laser together with a 0.5-m
-diameter beryllium telescope and a silicon avalanche photodiode are t
he principal optical subassemblies of this active remote-sensing instr
ument. Optical design rationale and measured optical performances duri
ng assembly and integration are presented.