Radar-Based Shape Model (2013)
The OSIRIS-REx team planned the spacecraft’s mission using a shape model of asteroid Bennu that was developed in 2013 and based on radar observations from Arecibo Observatory and Goldstone tracking station. Although the original model did not predict the surface topography of Bennu in detail, at least one large rock formation was predicted in the southern hemisphere.
New Preliminary Shape Model (Nov. 2018)
As the spacecraft approached and began surveying Bennu, data from the OSIRIS-REx Camera Suite (OCAMS) was used to create a new preliminary shape model. As it turns out, the original 2013 model closely predicted the asteroid’s actual shape, with Bennu’s diameter, rotation rate, inclination, and overall shape presented almost exactly as projected. This new model, which was created using a compilation of images taken by OSIRIS-REx’s PolyCam camera during the spacecraft’s approach in November 2018, shows features on Bennu as small as six meters.
Credit: NASA/Goddard/University of Arizona