NASA spacecraft successfully touches Bennu asteroid, collects dust and pebbles

In a first, NASA's OSIRIS-REx (Origins, Spectral Interpretation, Resource Identification, Security, Regolith Explorer) spacecraft successfully touched an asteroid's surface to collect dust and pebbles on October 20, 2020. The collected particles will be delivered to the Earth by 2023.  

NASA's OSIRIS-REx spacecraft briefly touched the surface of a well-preserved, ancient asteroid known as Bennu by unfurling its robotic arm. The asteroid is currently more than 200 million miles from Earth. 

The development is extremely significant, as it will offer scientists a window into the early solar system when it was first taking shape billions of years ago.

Touch-And-Go Sample Acquisition Mechanism

The sample collection method is known as the Touch-And-Go Sample Acquisition Mechanism (TAGSAM). If the method enabled the spacecraft to scrape up enough samples then the mission teams will command the spacecraft to begin its journey back home in March 2021 otherwise the spacecraft will prepare for another sample collection attempt in January 2021. 

How did the sample collection take place?

The OSIRIS-REx spacecraft first fired its thrusters to nudge itself out of the orbit around Bennu and then it extended the shoulder, then elbow, then wrist of its 11-foot sampling arm and transited across Bennu while descending about a half-mile towards the asteroid's surface.

The TAG mechanism precisely targeted a sample collection site known as Nightingale, one of the few relatively clear spots on the boulder-covered space rock. Shortly after it made contact with the surface, it fired its thrusters and safely backed away from Bennu.

Has the spacecraft collected enough samples?

• The Touch-And-Go Sample Acquisition Mechanism of the spacecraft was executed as expected, as per the spacecraft telemetry data. However, it will take the OSIRIS-REx research team at least a week to confirm the amount of sample collected by the spacecraft.

• The real-time data indicated that the spacecraft successfully contacted the surface of the asteroid and fired a burst of nitrogen gas, which should have stirred up enough dust and pebbles on the asteroid's surface, some of which should have been captured in the sample collection head.

• The OSIRIS-REx team's goal was to collect material weighing at least about 60 grams. The team's engineers and scientists will use several techniques to identify and measure the sample remotely. They will be first comparing the images of the sample collection site before and after touchdown and see how much disturbance has been caused to the surface material in the area.

• If the Touch-And-Go Sample Acquisition Mechanism of the spacecraft made a significant disturbance on the surface of the ancient asteroid then it is likely that it has collected a lot of material.

Return to Earth

The spacecraft will prepare for its home journey from Bennu in March 2021, when the asteroid will be properly aligned with Earth. In case the spacecraft has not collected enough samples then it will make another attempt on January 12, 2021. The spacecraft is scheduled to return back to Earth on September 24, 2023. 

Background

The OSIRIS-REx spacecraft was launched from Cape Canaveral Air Force Station in Florida on September 8, 2016. It had arrived at Bennu on December 3, 2018 and began orbiting the asteroid for the first time on December 31, 2018.