Canadian Instrument on OSIRIS-REx Took Most Detailed 3D Measurements of Any Celestial Body Ever Explored

An OLA scan that was taken over 5.5 minutes and contains 3,342,748 measurements. Shadows are in areas that were not visible from the perspective of OLA. (Credit: NASA/University of Arizona/Canadian Space Agency/York University/MDA)

LONGUEUIL, Quebec (CSA PR) — In a detailed study published today, Canadian scientist  Michael Daly (York University) and his team revealed that the data gathered by Canadian OSIRIS-REx Laser Altimeter (OLA) enabled new insights into near-Earth asteroid Bennu. The paper is part of a special collection on Bennu appearing today in Science and Science Advances.

On October 20, 2020, NASA’s OSIRIS-REx spacecraft will attempt to take a sample from Bennu in hopes of answering questions about how our solar system formed and how life on Earth may have begun. After a challenging process where scientists discovered that Bennu’s surface was much more rugged than initially expected, a site named “Nightingale” was officially chosen as OSIRIS-REx’s final target to collect a sample.

Without measurements taken by the Canadian instrument OLA, the selection of a sample site would have been much more difficult. OLA scanned the asteroid’s surface and took almost 3 billion individual measurements, spaced on average less than 5 cm apart, to create a 3D model of Bennu.

This “shape model” was also used to interpret Bennu’s geological history and better understand some of the changes that have occurred on its surface over time, as Daly and his colleagues report in the paper. Specifically, at some point in Bennu’s history, more large boulders accumulated in the southern hemisphere than in the north. Over time, these large boulders blocked the movement of finer surface material in the south, while fine material in the north moved more freely. As a result,  Bennu’s current shape is rounder and smoother in the south than it is in the north.

The OSIRIS-REx mission has been a unique opportunity for Canada to showcase its technical and scientific expertise. Thanks to the Canadian Space Agency’s contribution to the mission, Canada will receive a portion of the returned sample when it comes back to Earth in September 2023, to be made available for study by Canadian scientists for generations to come.