HR: 13:55h
AN: G53C-02 INVITED     [Abstracts]
TI: Measuring the Lunar Topography with the Laser Altimeter on LRO
AU: * Smith, D E
EM: David.E.Smith@nasa.gov
AF: NASA/GSFC, Code 690, Greenbelt, MD 20771 United States
AU: Zuber, M T
EM: zuber@mit.edu
AF: MIT, Dept. of Earth, Atmospheric and Planetary Sciences, Cambridge, MA 02139 United States
AB: One of the six selected instruments for the Lunar Reconnaissance Orbiter (LRO) mission due for launch in Oct 2008 is a laser altimeter to identify safe landing sites, determine the lunar topography, and establish a global geodetic coordinate system. The altimeter (LOLA) is a 1064 nm pulsed laser system operating at 28Hz which sends a single beam through a Diffractive Optical Element to produce five separate beams that illuminate the lunar surface. The reflected laser light is measured for time of flight, pulse spreading, and the transmit and the return energies. These 3 basic measurements provide altimetry, surface roughness, and surface reflectance. Each laser beam illuminates a 5-meter diameter spot from 50 km altitude and the resulting pattern allows unambiguous determination of slopes along and across the orbit track on a scale of 25 meters. The five laser range profiles illuminate the lunar surface approximately 10 meters apart parallel to the orbit track with a ranging accuracy of 10 cm. The LRO mission has a 1-year nominal lifetime with possibilities for an extended mission. The coverage after one year provided by the orbit of LRO, which is polar, and nominally circular at 50 km altitude, will be an average of ~1.2 km at the equator and complete at latitudes higher than 86 where there is considerable interest in a location for a future robotic landing and where the water ice has been postulated to exist in permanently shadowed craters.
DE: 1221 Lunar and planetary geodesy and gravity (5417, 5450, 5714, 5744, 6019, 6250)
DE: 1294 Instruments and techniques
SC: Geodesy [G]
MN: Fall Meeting 2005