Post contributed by Dr. Olivier S. Barnouin, The Johns Hopkins University Applied Physics Laboratory, USA
The OSIRIS-REx (Origins, Spectral Interpretation, Resource Identification, and Security–Regolith Explorer) spacecraft successfully sampled the surface of the asteroid (101955) Bennu on October 20, 2020. The sampling event revealed that Bennu’s surface was very weak and easy to displace. But this outcome was not necessarily evident when OSIRIS-REx first arrived at Bennu, given the asteroid’s very rocky surface and apparent lack of fine sand-sized surface material, or regolith (Image 1), until we began analyzing Bennu’s landscape in detail.
Image 1. Movie of high resolution (40 cm) digital terrain model of Bennu showing its rough, rubbly surface. Bennu’s diameter is ~500m. In this movie, the sun is held fixed at at 20 sub-longitude. Movie generated with Small Body Mapping Tool (sbmt.jhuapl.edu). Credit CSA/NASA/UA/APL.
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