Last month, NASA’s Osiris-Rex spacecraft’s Touch and Go landing revealed new insights into the structure of loose rocks covering the surface of a small asteroid – a ball-like object in the playground rather than a solid.
The structure of the outer layer of the asteroid is clear from images taken by the Osiris-Rex spacecraft on October 20 into an airless world 200 million miles (330 million km) from Earth.
The next day, NASA released imagery from a narrow-angle camera aimed at the spacecraft’s 11 – foot (3.4 m) robotic arm. At the end of the arm a dinner plate-sized sample collection device applied a bottle of compressed nitrogen gas, which the spacecraft contacted the surface of the asteroid Benu. A small planetary body measures one-third of a mile in diameter.
The emission of nitrogen gas helped to force the asteroid samples into the storage chamber. After six seconds on the surface of the asteroid, Osiris-Rex applied thrusters to pull back from Bennu.
Scientists later obtained close-up images of the sample collection head, which appeared to be broken by objects collected from the asteroid’s surface. Some asteroid particles were seen escaping from the collection chamber, prompting managers to order the spacecraft to keep the sample head inside its Earth return capsule faster than expected, minimizing sample loss.
The sample instrument was shut down on October 28 inside the return capsule of the Osiris-Rex spacecraft.
Last week, authorities released another series of images taken during the spacecraft’s Touch and Go landing. These were captured on the OSIRIS-REx with a wide angle navigation camera.
According to the Osiris-Rex science team, the navigation camera – or navcam – captured the images in about three hours. The sequence begins about an hour after Osiris-Rex applied an orbital strategy to begin its orbit, ending two minutes after the spacecraft’s back-away flare, officials said.
When Osiris-Rex points its sample arm to the target sample site at Ben’s asteroid Ben, the region known as the “Nightingale”, a sleeve or rotation can be seen in the center of the image sequence.
“As the spacecraft approaches the Nightingale site, the shadow of the sample arm appears at the bottom of the frame. Soon the sample head site, Nightingale (right above the field of view of the camera) is impacted and thrown into a nitrogen gas bottle, which collects a considerable amount of material from the sample site, ”the Osiris-Rex team wrote in a statement to NavCam Imagery.
“After a few seconds, the spacecraft makes a back-and-burn, and the shadow of the sample arm appears against the disturbed surface objects. The team continues to investigate why very dark areas appear at the top and center of the frame, ”the team wrote. “The upper area can be the edge of the depression created by the sample arm, casting a strong shadow with objects raised from the surface, or a combination of the two.
“Similarly, the central dark area that first appears in the lower left is the depression caused by the shooting of a spacecraft, the shadow caused by the lofted material, or a combination of the two.”
The Osiris-Rex spacecraft, built by Lockheed Martin, relied on black and white navigation camera images, leading itself to a safe touchdown zone in Benu. The navigation algorithms compare the camera’s images to the spacecraft’s computer’s pre-loaded map, allowing OSIRIS-REx to determine its position in comparison to the asteroid.
With its sample secured in the return capsule, Osiris-Rex is set to launch near the asteroid Benu next year to begin its journey to Earth. The spacecraft will return to return to Earth’s atmosphere and land on the Utah Test and Training Range on September 24, 2023.
NASA’s $ 1 billion Origin, Spectral Interpretation, Resource Identification, Security, and Regolith Explorer mission was launched on September 8, 2016 from Cape Canaveral on the United Launch Alliance Atlas 5 rocket. The primary goal of Osiris-Rex is to return asteroid samples to Earth for detailed analysis by scientists who hope to find clues to the origin of the Solar System.
The mission was to collect at least 60 grams or 2.1 ounces of asteroid material from Osiris-Rex. Ahead of the October 20 touchdown and landing, scientists said evidence suggests the spacecraft could collect more than 2.2 pounds or a kilogram of asteroid samples, according to Dante Loretta, Arizona, the university’s chief investigator.
Data from the asteroid’s brief touchdown indicate that the spacecraft’s robotic arm sank 19 inches (48 cm) into Bennu’s smooth surface.
While the mission’s scientific reward will wait until the asteroid samples return to Earth, Loretta said Thursday that scientists are already studying Bennu’s physical properties.
As soon as it reached the asteroid in December 2018, the spacecraft detected small particles flying from Bennu. These particles resemble objects leaking from a tagsam head.
“A box in space looks like cornflakes,” Loretta said. “They move randomly. They mostly come from the head of the tagsam, but they collide with each other. They spin and stumble. We can solve many of them.
“So this is an excellent imaging calibration data set up to better understand particle ejection events and the paths of the particles we observed throughout the collision with the asteroid,” Loretta said. “Although my heart was broken by the loss of the sample, it turned out to be a very interesting scientific experiment.”
On October 20, Osiris-Rex’s rich dataset with the asteroid surface was released, indicating that the asteroid’s outer crust and low-density rocks were not very compatible. The robotic arm of the spacecraft touched the asteroid when it reached just 0.2 miles per second, or 10 centimeters per second, at a speed of one tenth of a normal walking speed.
“When the tagsam head came in contact with the regolith, it flowed like a liquid,” Loretta said. “I think it would happen to her if an astronaut tried to walk on the surface of an asteroid. She will kneel or sink deep until you hit a large rock or bed of any kind – depending on how loose the soil is. ”
He said the “basic truth” information collected by Osiris-Rex would help scientists revisit models of asteroid geology.
“There is a lot of resistance from the asteroid to the spacecraft,” Loretta said. “Basically, it’s like a ball pit on a child’s playground. If you jump into it, you drown.
“Fortunately, we had those back-away thrusters to change the direction of motion, or we might have traveled through the asteroid,” Loretta joked.
New measurements of asteroid density from Osiris-Rex will help scientists assess the potential dangers that Benny could bring to Earth. By the end of the 2100s, 2,700 scientists out of 1 estimated that Bennu could affect Earth.
Most of the asteroid may burn in the Earth’s atmosphere.
“Thermal analysis indicates that many objects on the surface of the bean – especially the large black hammock rocks that make up the main component of the surface – seem to have the perfect properties that do not survive the passage through the atmosphere,” Loretta said. “They will crumble and lose most of the material.”
That is, natural specimens collected from Bennu are not like meteorites or asteroid fragments that fall to the ground and reach the surface.
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