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NASA OSIRIS-REx’s final asteroid observation operation



NASA OSIRIS-REx's final asteroid observation operation

The artist’s concept shows the planned flight path of the NASA OSIRIS-REx spacecraft during its final asteroid Bennu flyby scheduled for April 7.Image credit: NASA/Goddard/University of Arizona

NASA’s OSIRIS-REx mission is on the verge of discovering the level of chaos it caused on the surface of the asteroid Bennu during its sample collection activity last fall. On April 7, the OSIRIS-REx spacecraft will have the last close contact with Bennu as it will perform the final flyby to capture images of the asteroid̵

7;s surface. During the overflight, the spacecraft will observe Bennu at a distance of approximately 2.3 miles (3.7 kilometers), which is the closest distance since the “on the fly” sample collection event on October 20, 2020.

The OSIRIS-REx team decided to add the last flyover after Bennu’s surface was severely disturbed by the sample collection event. During the landing, the sampling head of the spacecraft sank 1.6 feet (48.8 cm) from the surface of the asteroid and simultaneously launched pressurized nitrogen. The spacecraft’s thrusters also mobilized a large amount of ground material during the receding combustion process. Because Bennu’s gravity is too weak, the various forces generated by the spacecraft have a huge impact on the sampling point-many rocks and a lot of dust in the area were launched in the process. Bennu’s last flyby will provide the mission team with an opportunity to understand how the spacecraft’s contact with the Bennu surface changed the sampling point and its surrounding area.

A single flyby will mimic a series of observations made during the “detailed investigation” phase of the 2019 mission. OSIRIS-REx will image Bennu for 5.9 hours, which happens to be the result of the entire rotation cycle of the asteroid. Within this time frame, the spacecraft’s PolyCam imager will obtain high-resolution images of Bennu’s northern and southern hemispheres and their equatorial regions. The team then compared these new images with high-resolution images of asteroids previously obtained in 2019.

Most of the spacecraft’s other scientific instruments will also collect data during the flyby, including the MapCam imager, OSIRIS-REx thermal emission spectrometer (OTES), OSIRIS-REx visible and infrared spectrometer (OVIRS), and OSIRIS-REx laser altimeter (OLA). Exercising these instruments will give the team an opportunity to evaluate the current status of each scientific instrument on the spacecraft, because dust will cover the instruments during the sample collection process. Knowing the health of the instrument is also part of NASA’s assessment of the possible expansion of mission opportunities after shipping samples to Earth.

After the Bennu flyby, it will take several days to download the data on the flyover to the earth. Once the data is downloaded, the team will check the images to understand how OSIRIS-REx interferes with the asteroid’s surface material. At this time, the team will also be able to evaluate the performance of scientific instruments.

The spacecraft will stay near the Bennu asteroid until May 10, when the mission will enter the return cruise phase and begin a two-year journey back to Earth. When approaching the Earth, the spacecraft will abandon the sample return module (SRC) containing the rock and dust collected from Bennu. The SRC will then cross the Earth’s atmosphere and land under a parachute at the Utah Test and Training Ground on September 24, 2023.

After recovery, the capsules will be transported to the agency’s curatorial facility at Johnson Space Center in Houston, where samples will be removed and distributed to laboratories around the world, enabling scientists to study the formation of the solar system and the Earth as a habitable planet.


NASA’s OSIRIS-REx bids farewell to Bennu


Courtesy of NASA’s Goddard Space Flight Center



Citation: NASA OSIRIS-REx’s final asteroid observation operation (April 1, 2021) retrieved from https://phys.org/news/2021-04-nasa-osiris-rex-asteroid.html to April 2, 2021 day

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