The OSIRIS-REx spacecraft is practicing its landing on the asteroid Bennu that is needed to get a safe touchdown for its eventual return with the samples.

A scheduled collection pick-up will occur in the fall on October 20. It will be the first NASA craft that will do this kind of mission and return automatically to Earth.

It will begin disembarking from the space rock approximately in 2021, and will begin the return flight 24 months after. Carrying samples from Bennu included 30 sugar packets to be examined by NASA and other space agencies, according to CNN.

It has been busy since 2018 while mapping Bennu and its surface for data gathering. The probe is about 179 million miles from its home world and is akin to NEO or near-earth-object. This NEO is speculated to get past the moon's distance in 2135, and that gets a bit closer in 2175 and 2915.

Scientists doubt that it might be a planet killer. All information from the mission will help to interdict planet killers or lesser sized asteroids. Samples from it will give insight into their nature and if they seeded the cosmos.

The probe has begun its TAG or Touch-and-Go sequence, that is carried out to get the samples ready for its return. Its maneuver will have it hovering 131-feet above site Nightingale, located in the interior of a crater in Bennu's northern hemisphere. Overall, the process took three of the four maneuvers to obtain the sample.

Stages were firing thrusters, get to a closer altitude, and temporarily leave the 0.6-mile distance from the surface. A checkpoint burn of thrusters was done at 410 feet surface distance. Automated sensors will correct the position and adjust to get any closer.

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Objective reached should be the matchpoint burn to keep the orbit stable, so it can hover over the site for taking samples. When the terminal 131-feet is achieved, the probe will deploy the Touch-and-Go-Sample Acquisition Mechanism. This is the arm that will collect samples scheduled in October.

Most of the devices on the probe have been used to observe and conduct its way around the orbit of the NEO, which includes collecting samples as well. Many of the ultra-clear images gotten through visual sensors assist in sample collection with it is tracking systems.

The Natural Feature Tracking guidance system will provide topographical data to keep out of danger, while in route to collect from site Nightingale. The AI with all the support systems will set the probe on the NEO for the final phase in October.

Commands will be sent from Earth to the NEO in 16 minutes, calculated from its present distance. They will be sent earlier to the probe, and all the necessary instructions to the AI before the touchdown. Instructions were tested before the big day.

Part of the rehearsal is checking all systems are working without a hitch, before the probe goes to work.  According to Dante Lauretta, connected to the OSIRIS-Rex mission, all major and critical systems like communications, thrusters, and the tracking and guidance sensors, are inspected to assure success, according to Scientific American.

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