An Addition to our Space Rock Collection
On October 20th, our OSIRIS-REx mission will make its first attempt to collect and retrieve a sample of asteroid Bennu, a near-Earth asteroid. On sample collection day, Bennu will be over 200 million miles away from Earth.
Asteroids are the building blocks of our solar system. A sample of this ancient material can tell us about the history of our planet and the origins of life. Science results published from the mission on October 8th confirm that Bennu contains carbon in a form often found in biology or in compounds associated with biology.
To collect a sample, OSIRIS-REx will attempt a method NASA has never used before – called Touch-And-Go (TAG). First, the spacecraft extends its robotic sampling arm, the Touch-And-Go Sample Acquisition Mechanism (TAGSAM) – from its folded storage position. The spacecraft’s two solar panels then move into a “Y-wing” configuration over the spacecraft’s body, which positions them safely up and away from the asteroid’s surface during touch down. This configuration also places the spacecraft’s center of gravity directly over the TAGSAM collector head, which is the only part of the spacecraft that will contact Bennu’s surface.
Finding a safe sample collection site on Bennu’s rocky landscape was a challenge. During the sampling event, the spacecraft, which is the size of a large van, will attempt to touch down in an area that is only the size of a few parking spaces, and just a few steps away from enormous boulders.
The spacecraft will only make contact with Bennu for a matter of seconds - just long enough to blow nitrogen gas onto the surface to roil up dust and small pebbles, which will then be captured for a return to Earth.
We need to conduct a few tests before we can confirm we collected a large enough sample (about 2 oz). First, OSIRIS-REx will take images of the collector head to see if it contains rocks and dust. Second, the spacecraft will spin with the TAGSAM extended to determine the mass of collected material. If these measures show a successful collection, we will stow the sample for return to Earth. If sufficient sample has not been collected, the spacecraft has onboard nitrogen charges for two more attempts. The next TAG attempt would be made no earlier than January 2021.
Despite the many challenges, the OSIRIS-REx team is ready. They’ve practiced and prepared for this moment.
Join in with #ToBennuAndBack and tune in on October 20th.
Learn more about the OSIRIS-REx countdown to TAG HERE.
Learn more about the OSIRIS-REx mission HERE, or follow the mission on Facebook, Twitter and Instagram.
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