Osiris-Rex should be just about ready to touch down. The robotic craft will make contact with the asteroid Bennu as early as tomorrow. It’ll gather a small amount of dust and pebbles for return to Earth.

The probe is scheduled to deploy a sample collector at the end of its robotic arm, then inch toward the surface. It will compare real-time images of the surface to a map of its landing site to make sure it’s on target.

When the arm makes contact, it’ll fire a burst of gas to kick a few particles into the collector. After just five seconds, Osiris-Rex will back away to evaluate its catch. If the attempt worked, it’ll return to orbit. If not, it’ll try again. It can try three times.

Once the sample has been verified, it’ll be placed in a capsule for return to Earth in three years.

Osiris-Rex arrived at Bennu in December 2018. It’s compiled a thorough dossier on the asteroid, which is about a third of a mile wide.

The notes include details on how Bennu’s orbit changes as the asteroid absorbs solar energy on its dayside and radiates it back into space on the nightside. Those observations are important because Bennu comes close to Earth about every six years. It has a 1-in-2700 chance of hitting Earth in the 22nd century. And it’s large enough to cause major damage. Better models of the orbit will help scientists refine the odds — and perhaps leave enough time to fend off a possible cosmic collision.

Script by Damond Benningfield

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