<h2>AAS 99-171</h2>
<h2>Comparison of Optical and Radar Orbital Debris Measurements                                                                                      </h2>
<h4>J.L. Africano*, T.J. Settecerri**, E.G. Stansbury**                                                                                                                                 </h4>
*Boeing North American, **Lockheed Martin Space Mission Systems and Services, ***NASA JSC                                                                                 
<h2> Abstract </h2>
NASA/JSC has been conducting ground based orbital debris measurements since 1990. Since that time 4700 hours of Haystack radar has been processed and nearly 2500 hours of the HAX since 1994. These data sets have provided a wealth of data that has been used to characterize the orbital debris environment, directly through the measurements and indirectly through model development. The radar has also identified previously unknown debris families based on inclination and altitude. The NASA Liquid Mirror Telescope (LMT) Project has been collecting data on the LEO debris environment since April 1996. From April 1996 through April 1997, 72 hours were collected using an analog recording system. These videotapes have been screened for all moving objects. Preliminary results indicate that 190 uncorrelated targets (UCT) and 61 catalogued objects were detected. The newly analyzed LMT data complements the radar data quite well. It also will be used to look for possible differences between the optical and radar measurements.