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NOVA: Touching the Asteroid

OSIRIS-REx attempts to bring a piece of asteroid Bennu back to Earth

  • Christina Zeiders
NASA's OSIRIS-REx is ready for touchdown on asteroid Bennu. On Aug. 11, the mission will perform its “Matchpoint” rehearsal – the second practice run of the Touch-and-Go (TAG) sample collection event. The rehearsal will be similar to the Apr. 14 “Checkpoint” rehearsal, which practiced the first two maneuvers of the descent, but this time the spacecraft will add a third maneuver, called the Matchpoint burn, and fly even closer to sample site Nightingale – reaching an altitude of approximately 131 ft (40 m) – before backing away from the asteroid.

This artist's rendering shows OSIRIS-REx spacecraft descending towards asteroid Bennu to collect a sample of the asteroid’s surface. (Aug 10, 2020)

NASA/Goddard/University of Arizona

NASA's OSIRIS-REx is ready for touchdown on asteroid Bennu. On Aug. 11, the mission will perform its “Matchpoint” rehearsal – the second practice run of the Touch-and-Go (TAG) sample collection event. The rehearsal will be similar to the Apr. 14 “Checkpoint” rehearsal, which practiced the first two maneuvers of the descent, but this time the spacecraft will add a third maneuver, called the Matchpoint burn, and fly even closer to sample site Nightingale – reaching an altitude of approximately 131 ft (40 m) – before backing away from the asteroid. This artist's rendering shows OSIRIS-REx spacecraft descending towards asteroid Bennu to collect a sample of the asteroid’s surface. (Aug 10, 2020)

In October 2020, NASA spacecraft OSIRIS-REx attempted to reach out and grab a piece of an asteroid named Bennu to bring it back to Earth. NOVA: Touching the Asteroid follows the high-stakes mission. Watch this special Wednesday, June 1 at 9pm on WITF TV, the PBS Video app, or witf.org/watch.

Watch NOVA: Touching the Asteroid on WITF TV Wednesday, June 1 at 9pm. WITF TV can be streamed live through the PBS Video app or at witf.org/watch. WITF Passport members can stream this documentary on-demand through the PBS Video app and at video.witf.org.

The OSIRIS-REx team had just three chances to extend its spacecraft’s specialized arm, touch down for five seconds, and collect material from the surface of Bennu. But if they pull it off, scientists could gain great insights into Earth’s origins – and learn to defend against rogue asteroids that may one day threaten our planet.

Scientists spent years preparing for the launch, touchdown, and sample collection. They chose Bennu, which was more than 200 million miles from earth, because they believed it would have a sandy, beach-like surface, which would make it easy to collect a sample.

But they were wrong – the surface was actually very rocky. After taking thousands of photos, they found an ideal sample site called “Nightingale,” which was much smaller than they hoped for. The team wanted a safe landing zone of about 164 feet but had to land in an area only 26 feet wide.

NOVA | Read: In a swirl of rocks and dust, OSIRIS-REx probe touches an asteroid

Watch Touching the Asteroid Wednesday, June 1 at 9pm on WITF TV, the PBS Video app or witf.org/watch. WITF Passport members can watch on-demand through the PBS Video app and at video.witf.org.

Even with a more challenging landing, OSIRIS-REx successfully touched the surface. A team at Lockheed Martin spent years developing the sample collection technology needed to complete this mission, TAGSAM, or the “Touch And Go Sample Acquisition Mechanism.”

OSIRIS-REx used an 11-foot arm to reach down and touch the surface of the asteroid with a collection device. From there, high-pressure nitrogen gas was used to disturb the soil and suck up as much rock, dirt, and dust as it could. Then the sample was stowed in OSIRIS-REx for its return to earth.

NOVA | Read: NASA’s OSIRIS-REx spacecraft will stow asteroid Bennu sample early

Asteroids are remnants of the earliest periods in solar system history. Scientists hope to use the samples collected from Bennu to unlock the secrets of our solar system’s origins and learn more about how the planets formed.

OSIRIS-REx’s journey is not complete. It will bring its sample of Bennu back to earth by dropping a capsule in the Utah desert in 2023.

NOVA: Touching the Asteroid originally premiered on WITF TV in October 2020. Watch this rebroadcast on WITF TV, the PBS Video app or witf.org/watch Wednesday, June 1 at 9pm. WITF Passport members can stream this documentary on-demand through the PBS Video app and at video.witf.org.

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