OSIRIS-REx probe rehearses asteroid sampling from lowest altitude yet

NASA’s OSIRIS-REx spacecraft has been circling the primitive asteroid Bennu for more than a year now, with mission control gearing up for its sample collection maneuver later this year. The unmanned probe has ticked off another key milestone on this epic journey, successfully completing a first practice run of a complex sampling sequence in close proximity to the asteroid’s surface.

All going to plan, the OSIRIS-REx will grab a sample from the surface of Bennu using an instrument called the Touch-and-Go Sample Acquisition Mechanism (TAGSAM). This 11-ft (3.4-m) articulating arm features a rounded sampling head and bottles of high-pressure nitrogen gas, which will be blasted into the surface to stir up some rubble for collection.

NASA had OSIRIS-REx begin testing out the deployment of this instrument from orbit back in 2018, ensuring that it could be extended and retracted as needed. The team is now edging closer to the real deal, with its most recent rehearsal taking place while hovering over its sample collection site, known as Nightingale.

The spacecraft departed from its 0.6-mi (1-km) orbit and reached an altitude of just 410 feet (125 m) four hours later. This point is known as the Checkpoint, as it is where the spacecraft autonomously verified its position and velocity before altering its path toward its next stop, an altitude of just 75 m (246 ft).

This was the closest OSIRIS-REx has ever come to the surface of Bennu, and provided the team with an opportunity to unfurl the TAGSAM instrument to its full sample collection configuration amid the sequence of maneuvers.

The rehearsal also enabled the team to run through the navigation procedures for the orbit departures and various burn maneuvers, while also making sure the imaging and data collection instruments were in working order. OSIRIS-REx also gathered data and observations of the sample site throughout, as it will do during the real sampling procedure later this year.

That is scheduled to take place on August 25, with the spacecraft hoped to return to Earth with its sample in tow on September 24, 2023.

Source: NASA

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