THE NATURAL FEATURE TRACKING AND LIDAR HYBRID APPROACH FOR OSIRIS-REX SAMPLE COLLECTION

The Origins Spectral Interpretation Resource Identification and Security-Regolith Explorer (OSIRIS-REx) mission utilizes an autonomous method for collecting a regolith sample from the surface of the asteroid Bennu. This sampling event is referred to as "TAG", or Touch and Go. A new design concept has been developed which utilizes a combination of autonomous optical navigation and rendezvous capabilities and is referred to as "Hybrid TAG". The primary sensors for executing Hybrid TAG include a Navigation Camera built by Malin Space Science Systems and a flash Lidar system built by Advanced Scientific Concepts. The baseline method for executing TAG utilizes only the Lidar sensor. A backup method was also later developed using optical navigation, referred to as Natural Feature Tracking (NFT). The recently developed Hybrid design combines the strengths of both these methods as it includes accurate asteroid-relative navigation using Natural Feature Tracking followed by high rate Lidar range measurements for approaching the sample collection site. This approach has the potential to improve TAG accuracy when compared to the Lidar-only method and also potentially allows a wider range of possible TAG sites to be accessible. These advantages are contingent on the environment encountered at Bennu and depending on what is discovered as the mission explores Bennu, the most appropriate TAG method will be chosen to collect the sample. This new Hybrid TAG method reduces risk and improves the robustness of the OSIRIS-REx primary science objective.