Spacecraft revolves around small Bennu, breaks record | Space

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Yesterday – while many on Earth flew in the new year – a NASA spacecraft broke 70 million miles (110 million km) a scout record. NASA & # 39; s OSIRIS-REx spacecraft carried out its thrusters for a single eight seconds and traversed Asteroid Bennu near the Earth, making Bennu the smallest object still being driven around by a spacecraft. And Bennu is indeed very small. It has an average diameter of approximately 1,614 feet (496 m, 492 m). The incineration took place on December 31, 2018 at 18:43 UTC (2:43 PM EST). Dante Lauretta, OSIRIS-REx principal investigator at the University of Arizona Tucson, said:

The team [performed] the job-input maneuver perfectly. Now that the navigation campaign is over, we look forward to the scientific mapping and sample selection phase of the mission.

He added:

Entering a job around Bennu is a great achievement that our team has been planning for years.

A team statement indicated that Bennu – named after an ancient Egyptian mythological bird related to the sun, creation and rebirth – has scarcely enough gravity to keep a vehicle in a stable orbit.

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The previous record holder for orbit of a planetary body was the Rosetta spacecraft, which circled in May 2016 about 6.5 kilometers from the center of comet 67P / Churyumov-Gerasimenko. OSIRIS-REx is much closer to Bennu, about a mile (1.6 km) from the center. This distance is necessary to keep the spacecraft locked up for Bennu, these space scientists said, because Bennu's gravity is only five millionths as strong as that of the earth.

The spacecraft is scheduled to circle Bennu until mid-February at a relaxed 62 hours per track.

This mosaic image of asteroid Bennu is composed of 12 PolyCam images collected on 2 December 2018 by the OSIRIS-REx spacecraft from a series of 24 kilometers. Image via NASA / Goddard / University of Arizona.

OSIRIS-REx & # 39; s system manager for flight dynamics Mike Moreau, who is based at NASA's Goddard Space Flight Center in Greenbelt, Maryland, said:

Our job design is highly dependent on Bennu's physical characteristics, such as the mass and gravitational field, which we did not know before we arrived.

So far, we had to consider a wide range of possible scenarios in our computer simulations to ensure that we could safely navigate the spacecraft close to Bennu. When the team learned more about the asteroid, we processed new information to improve the final job design.

Although OSIRIS-REx is possible in the most stable track, the team said, Bennu's gravity is so weak that keeping the spacecraft safe from time to time requires adjustments. Then Wibben, OSIRIS-REx maneuver and job design at KinetX Aerospace in Simi Valley, California, said:

The gravity of Bennu is so small, forces such as solar radiation and thermal pressure from Bennu's surface become much more relevant and can push the spacecraft much further in its orbit than when it orbits the Earth or Mars, where gravity is by far the most is dominant force.

An important goal of this orbital phase, said the team, is to get a better grip on Bennu's mass and gravity, functions that will affect the planning of the rest of the mission, especially the short landing on the surface for sample collection in 2020. In the case of Bennu, scientists can measure these characteristics only by getting OSIRIS-REx very close to the surface to see how his or her job is deflected by Bennu's gravity.

The OSIRIS-REx mission is scheduled to bring the sample to Earth in September 2023.

Asteroid Bennu is considered to be a potentially dangerous object, because the track brings it close to the earth and is large enough to cause significant damage in the event of a collision. It has a cumulative probability of 1 to 2,700 to hit the earth between 2175 and 2199.

Read more from University of Arizona

Artist concept of OSIRIS-REx spacecraft on asteroid Bennu. The spacecraft is scheduled for a sample collection in 2020 and will return to earth in 2023. View through Heather Roper / University of Arizona.

Conclusion: NASA & # 39; s OSIRIS-REx spacecraft successfully burned on 31 December 2018 at 18:43 UTC (2:00 PM EST) and ended up in the vicinity of the Earth near asteroid Bennu. The maneuver makes Bennu the smallest object that has yet to be circulated by a spacecraft.

Deborah Byrd

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