Space Lidar Developed at the NASA Goddard Space Flight Center—The First 20 Years

During the past 20 years the NASA Goddard Space Flight Center has developed five different lidar for space, and has successfully used them in orbital missions to map Mars, the Earth, the Moon and Mercury. Although similar in some ways, each of these lidar has had a different combination of measurement requirements, payload constraints, and operational environments. Together they have improved space-based laser measurement technologies and advanced planetary science. This paper gives a brief overview of these instruments, their measurement approaches and designs, and some highlights from their scientific observations.