NEAR Laser Rangefinder - A tool for the mapping and topologic study of Asteroid 433 Eros

In 1999, after a three-year transit through space, the Near Earth Asteroid Rendezvous (NEAR) spacecraft will place a scientific payload consisting of five instruments into a low-altitude orbit (about 35 km) about the asteroid 433 Eros for one year. One instrument, the NEAR Laser Rangefinder (NLR), will use IR laser pulses to provide astrophysicists with precision altimetry data, measurements that were previously unavailable from asteroid observations. These data will accurately map Eros's topology, identify, and characterize small-scale surface features, and precisely determine overall volume and mass once they are combined with navigation data. Objectives associated with the NLR science mission are presented along with performance specifications and instrument design details. The method by which NLR performance was analyzed is described, as are tests used to verify its performance and operability. During performance testing, an 'end-to-end' test was conducted, where the integrated NLR instrument was operated in free space using a 216.4-m hallway. Test results fully verified all instrument interfaces and indicated that NLR performance parameters were well within all specifications. (Author)