NASA's OSIRIS-REx Preparing For Asteroid Touchdown With Final Rehearsal

The OSIRIS-REx mission will be performing a "Matchpoint" rehearsal next week, months after the first rehearsal. It will be the mission's final rehearsal before the actual Touch-and-Go (TAG) event this coming fall.

It was on April 14 when the OSIRIS-REx mission team completed the "Checkpoint" rehearsal wherein they practiced the first two maneuvers that the OSIRIS-REx spacecraft will perform during October's sample collection event. On Tuesday, Aug. 11, the team will add the third maneuver, the matchpoint burn, and fly closer to the sample collection site during the matchpoint rehearsal.

"Many important systems will be exercised during this rehearsal – from communications, spacecraft thrusters and, most importantly, the onboard Natural Feature Tracking guidance system and hazard detection," OSIRIS-REx Principal Investigator Dante Lauretta of the University of Arizona said in a news release. "Once we complete this milestone, we will move forward with confidence to the sample collection event that lies ahead."

During the matchpoint rehearsal, OSIRIS-REx will perform the matchpoint burn for the first time. It will be the closest that it has ever been to asteroid Bennu before backing away from it again once it has completed the rehearsal. Then, once the team has verified that OSIRIS-REx performed as planned, it will be commanded to return to its safe-home orbit around the asteroid.

Because the one-way light time for signals between the Earth and OSIRIS-REx will be about 16 minutes during the rehearsal, the mission team will not be able to give the commands to the spacecraft live. Instead, the team will uplink all of the commands beforehand so that OSIRIS-REx can perform all the necessary actions autonomously once they give the "go" command.

On the actual TAG event on Oct. 20, it will complete all the maneuvers but, its sampling mechanism will actually reach the surface where it will fire a charge of pressurized nitrogen to disturb the surface in order to collect a sample.

Should things go according to plan, OSIRIS-REx will be able to collect a sample from asteroid Bennu and return it to Earth on Sept. 24, 2023.

The hope is for OSIRIS-REx to collect at least 60 grams of dirt and rocks that scientists can investigate. Because material from Bennu is much like a time capsule from the time of the early solar system, studying samples could provide clues regarding the formation of the solar system nearly 4.5 billion years ago. It may even help scientists better understand the possible role that asteroids may have played in bringing life-forming compounds to Earth.