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Home / Science / Scientists offer new perspectives from the OSIRIS-REx dam and capture – Spaceflight Now

Scientists offer new perspectives from the OSIRIS-REx dam and capture – Spaceflight Now



This view from the navigational camera of the OSIRIS-REx spacecraft shows the asteroid Bennu as the probe moves to a sample collection maneuver on October 20th. Image Provider: NASA / Goddard / University of Arizona / Lockheed Martin

Scientists said NASA’s OSIRIS-REx spacecraft touched and landed on an asteroid last month revealed new insights into the structure of loose rocks that could cover the surfaces of many. Small planetary celestial bodies – material more like a playground ball hole than a foundation solid.

The structure of the outermost layer of the asteroid is evident in images taken by the OSIRIS-Rex spacecraft as it swoops down to the airless world more than 200 million miles (330 million km) away from Earth on the day October 20.

The next day, NASA released an image from a narrow-angle camera aimed at the spacecraft’s 11-foot (3.4-meter) long robotic arm. A dish-sized device at the end of the arm shoots out a bottle of compressed nitrogen when the spacecraft comes in contact with the surface of the asteroid Bennu, a small asteroid about a third of a mile in diameter. .

The release of nitrogen gas helped propel the asteroid samples into the collection chamber. After six seconds on the surface of the asteroid, OSIRIS-REx fired the propulsion engines back from Bennu.

The scientists then received close-up images of the probe, showing it was stuffed with matter picked up from the asteroid surface. Several visible asteroid particles escaped the collection chamber, prompting spacecraft commanders to load the sample head into its return-to-Earth chamber earlier than expected, minimizing losses. sample.

The sampler was sealed inside the return chamber of the OSIRIS-REx spacecraft on October 28.

Last weekend, officials released a series of other images taken during the spacecraft’s touch and landing. They were captured using the wide-angle navigation camera on OSIRIS-REx.

According to the scientific group OSIRIS-REx, the image of the positioning camera – also known as NavCam – was taken over a period of about three hours. The sequence began about an hour after OSIRIS-REx made the out-of-orbit maneuver to begin landing and ended about two minutes after the spacecraft caught fire, officials said.

A rotation or rotation is visible in the middle of the series of images as OSIRIS-REx directs its sampling arm toward the target sampling position on the asteroid Bennu, an area called “Nightingale.”

“As the spacecraft approached the Nightingale site, the shadow of the sampled arm appeared in the lower part of the frame. Immediately after that, the sampler impacted the Nightingale site (just outside the camera field of view in the upper right) and fired off a bottle of nitrogen gas, which mobilized a considerable amount of geomaterials. sampling point ”, the OSIRIS-REx team wrote in a description of the NavCam image.

“Seconds later, the spacecraft performs a backburn and the shadow of the sampling arm is visible on the disturbed material surface. The team continues to investigate what caused the visible polar regions in the upper and middle parts of the frame, ”the team wrote. “The area above could be the edge of the depression created by the sampling arm, a strong shading created by the material protruding from the surface or some combination of the two.

“Similarly, the dark area in the middle that appears first in the lower left of the image may be the depression caused by one of the spacecraft’s propulsion devices when it shoots, the ball caused by the loft material, or combine the two. “

The OSIRIS-REx spacecraft, built by Lockheed Martin, relies on black and white navigation camera images to automatically guide itself to a safe touchdown area on Bennu. Navigational algorithms compare the camera’s image with a map preloaded into the spacecraft’s computer, helping OSIRIS-REx determine its position relative to the asteroid.

With its sample secured in the return chamber, OSIRIS-REx is set to depart the vicinity of the asteroid Bennu next year to begin the trip back to Earth. The spacecraft will drop the capsule back to re-enter the Earth’s atmosphere and land at the Utah Training and Test Park on September 24, 2023.

Artist’s illustration of a spaceship OSIRIS-REx with an extended sampling arm. Image provider: NASA

Mission Origin, Spectral Interpretation, Resource Identification, Security, NASA $ 1 billion Regolith Explorer launched on September 8, 2016, from Cape Canaveral on a United Launch Alliance Atlas 5 rocket The main goal of OSIRIS-REx is to return asteroid samples back to Earth for detailed analysis by scientists who hope to uncover clues about the origin of the solar system.

The mission requirement is that OSIRIS-REx must collect at least 60 grams, or 2.1 ounces, of the asteroid material. According to Dante Lauretta, the mission’s lead investigator from the University, the scientists said before October 20 touch and land that the spacecraft could collect much more, and the evidence suggests it has the ability to get more than 2.2 pounds, or 1 kilogram, of asteroid specimens, according to Dante Lauretta, the mission’s lead investigator from the University of Arizona.

Data from a brief encounter with the asteroid showed that the spacecraft’s robotic arm sank up to 19 inches (48 cm) deep into Bennu’s soft surface.

While the mission’s science mission will wait until the asteroid samples return to Earth, Lauretta said Thursday that scientists are learning about Bennu’s physical properties.

The spacecraft detected small particles flying out of Bennu shortly after it reached the asteroid in December 2018. Those particles appear similar to the fragmentary matter leaking out of TAGSAM’s head.

“It looks like a box of cornflakes in space,” Lauretta said. “And they fly around in random movements. Most of them come from the TAGSAM header, but they are colliding with each other. They are spinning and tumbling. We can address many of them.

“So that’s an excellent image correction dataset to better understand the particle launch events and the orbits of the particles that we observed during our encounter with the sub,” Lauretta said. planet, ”said Lauretta. “Even though my heart was broken from the loss of the model, it turned out to be quite an interesting scientific experiment.”

OSIRIS-REx’s exposure to the asteroid surface on October 20 also provided a rich set of data, showing that the outer layer of the low-density rock and soil lacks many bonds. The spacecraft’s robotic arm hits the asteroid as OSIRIS-REx approaches at just 0.2 miles per hour, or 10 centiemters per second, which is about one-tenth the speed of a normal walking speed.

“When the TAGSAM head comes in contact with the regolith, it flows away like a liquid,” Lauretta said. “And I think that’s what happens to an astronaut if she tries to walk on the surface of an asteroid. She will bend down or go deeper – depending on how loose the soil is – until you hit a larger rock or some kind of foundation.

“Basic facts” data collected by OSIRIS-REx will help scientists re-examine asteroid geological models, he said.

“It is interesting that there is very little resistance to the spacecraft from the asteroid surface,” Lauretta said. “Basically, it’s like a ball hole in a children’s playground. You jump on it and you just sink in.

“Luckily we had those repulsive motors to reverse the direction of motion, or we could just fly over an asteroid,” Lauretta joked.

New measurements of asteroid density from OSIRIS-REx will help scientists refine their assessment of the potential impact that Bennu could have on Earth. Scientists calculated a 1 in 2,700 probability that Bennu could strike the Earth in the late 2100.

Most asteroids can ignite in Earth’s atmosphere due to its porosity.

“Thermal analysis shows that a lot of the matter on the surface of Bennu – especially the large black hummocky rocks that are the main component of the surface – seem to have material properties that cannot exist when walking. through the atmosphere intact, ”Lauretta said. “They will be fragmented and most of the document will be lost.”

That means the pristine specimens collected from Bennu do not resemble any meteorite or asteroid debris that has fallen to Earth and reached an intact surface.

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Follow Stephen Clark on Twitter: @ StephenClark1.




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