Lasers in Earth and planetary exploration

Summary form only given.For over 3 decades lasers have been a tool of the space programs of the world for accomplishing a variety of engineering and scientific objectives. The majority of these uses have, however, been largely Earth-based and only a few lasers have actually been flown and operated in Earth orbit and even fewer on missions to the planets. However, in the last few years laser altimeters, lidars, and ranging systems have been part of space missions to the Moon, an asteroid, and Mars; and more are planned and contemplated in the future exploration of the solar system. On September 11, 1997 the Mars Global Surveyor (MGS) entered into orbit around Mars. One of the four scientific instruments on MGS is the Mars Orbiter Laser Altimeter (MOLA) which has started to map the topography of the planet to unprecedented accuracy. In January 1999 the NEAR Spacecraft, which carries a laser ranger (NLR), will arrive at the asteroid Eros and over the period of a year the NLR will determine the shape and the dynamics of the body. MOLA and NLR, along with the Clementine laser altimeter that went to the Moon in 1992 and changed many of our perceptions of the Moon, represent a new class of active remote sensing instruments for conducting science in the solar system. With them and their successors we can begin to unravel many of the intriguing questions surrounding the formation, dynamics and evolution of the planets, and even the solar system itself. Data recently acquired at Mars, around Earth and Moon, and ideas for the future will be presented in the context of what we are learning about Earth and our nearest neighbors.