Flash Lidar On-Orbit Performance at Asteroid Bennu

Abstract

NASA’s Origins, Spectral Interpretation, Resource Identification, and Security-Regolith Explorer (OSIRIS-REx) spacecraft is currently orbiting asteroid (101955) Bennu with the ultimate goal of collecting a sample from the asteroid’s surface and returning it to Earth. After launching from Cape Canaveral Air Force Station in September 2016, the OSIRIS-REx spacecraft travelled for nearly two years before arriving at asteroid Bennu in December 2018. Before entering orbit around Bennu, the spacecraft conducted a series of detailed surface scans. At the time, this achievement marked the closest orbit of a planetary body by a spacecraft, approximately 1.3 km, and set the record for Bennu as the smallest body ever orbited. Surveillance of Bennu continued in preparation for selecting a site to collect a regolith sample from the surface. The flash LIDAR is one of the navigation sensors for the Touch and Go (TAG) event. Several checkouts of the instrument were performed in flight including lasing at the surface of Bennu to verify its performance. Analyzing the LIDAR data over the asteroid surface against the shape model produced range data well within accuracy requirements. The LIDAR has performed nominally in flight as the first flash LIDAR used in a deep space mission. There has been no degradation to the laser and sensor, and no optical alignment issues have been observed.