Building a High-resolution Digital Terrain Model of Bennu from Laser Altimetry Data

The Origins, Spectral Interpretation, Resource Identification, and Security-Regolith Explorer (OSIRIS-REx) spacecraft orbited the near-Earth asteroid (101955) Bennu to characterize the asteroid prior to sampling. One important aspect of this characterization was the creation of a high-resolution (5–7 cm) global shape model using the OSIRIS-REx Laser Altimeter (OLA). We describe the data collected by OLA, along with the approach used to register overlapping topography using keypoints and keypoint descriptors in order to produce a globally self-consistent set of data. These globally registered sets of topographic scans were used to generate digital terrain models at both global and regional scales. We also describe efforts to correct for a change in behavior of the scanning mirror after the launch and highlight the improvements to the data after implementing an updated calibration of the mirror. The resulting model represents the highest-fidelity global OLA data set.