Scientists said last month that NASA’s OSIRIS-REx spacecraft hit and landed on an asteroid, uncovering fresh insights into the structure of loose rocks that could cover the surface of many small planetary bodies, which are closer to playground pit than solid. radical.
The structure of the outermost layers of the asteroid is evident in the images captured by the OSIRIS-REx spacecraft when the OSIRIS-REx spacecraft raided into an airless world more than 200 million miles (330 million kilometers) from Earth on October 20th. .
The next day, NASA released images of a narrow-angle camera aimed at a robotic arm that was 3.4 meters (11 feet) long. A dish-sized sample collection device at the tip of the arm fired a bottle of compressed nitrogen gas as the spacecraft made contact with the surface of a small planet about 1/3 mile in diameter, the asteroid Bennu.
The release of nitrogen gas helped to force the asteroid specimen into the collection chamber. Six seconds later from the asteroid’s surface, OSIRIS-REx fired a thruster to retreat from Bennu.
Scientists later received close-up images of the sample collection head, showing that it was filled with material that rose from the asteroid’s surface. Some asteroid particles could be seen escaping from the collection chamber, and managers ordered the spacecraft to keep the sample head inside the Earth Return Capsule earlier than expected, minimizing sample loss.
The sampling device was sealed inside the return capsule of the OSIRIS-REx spacecraft on October 28th.
Late last week, officials released another series of images taken while the spacecraft touched and landed. These were captured with OSIRIS-REx’s wide-angle navigation camera.
According to the OSIRIS-REx scientific team, the navigation camera or NavCam image was captured over about 3 hours. This sequence begins about an hour after OSIRIS-REx performs an out-of-orbit maneuver to start the descent, and ends about 2 minutes after the spacecraft retracts.
A rotation or rotational motion is seen in the middle of the image sequence as the OSIRIS-REx points the sampling arm towards the target sampling site of the asteroid Bennu, a region named “Nightingale”.
“As the ship gets closer to the Nightingale base, the shadow of the sampling arm is visible at the bottom of the frame. Soon after, the sampling head hits the nightingale site (just outside the camera’s field of view in the top right) and fires a bottle of nitrogen gas, mobilizing a significant amount of material from the sample site,” the OSIRIS-REx team wrote in the description. Of NavCam images
“After a few seconds, the spacecraft causes a posterior burn and the shadow of the sampling arm is visible on the obstructed surface material. The team continues to investigate the cause of the extremely dark areas visible in the top and middle of the frame,” wrote Tim. “The top area could be the edge of the dent created by the sampling arm, a strong shadow cast by the material lofted from the surface, or a combination of the two.
“Likewise, the middle dark area that first appears in the lower left corner of the image could be a depression by one of the spacecraft thrusters when firing, a shadow caused by the lofted material, or a combination of both.”
The OSIRIS-REx spacecraft, built by Lockheed Martin, relied on black and white navigation camera images to autonomously guide them to Bennu’s safe ground zone. The navigation algorithm helps OSIRIS-REx determine the position relative to the asteroid by comparing the image from the camera to a map preloaded on the spacecraft’s computer.
Having secured the sample in the return capsule, OSIRIS-REx is set to begin its return trip to Earth next year, departing near the asteroid Bennu. The spacecraft will re-enter Earth’s atmosphere on September 24, 2023 and release a return capsule for landing at Utah test and training grounds.
NASA’s $1 billion origin, spectrum interpretation, resource identification, security, and Regolith Explorer mission began on September 8, 2016 at Cape Canaveral aboard the United Launch Alliance Atlas 5 rocket. The main goal of OSIRIS-REx is to return a sample of the asteroid to Earth for detailed analysis by scientists hoping to uncover clues about the origin of the solar system.
The mission requirement was for OSIRIS-REx to collect at least 60 grams (2.1 ounces) of asteroid material. Scientists said the spacecraft could collect much more before landing on October 20, and evidence suggests that it is likely to lift more than 2.2 pounds (1 kg) of asteroid specimens, said University’s Dante Lauretta. Arizona.
Short touchdown data on the asteroid showed that the spacecraft’s robotic arm sank up to 19 inches (48 cm) on Bennu’s smooth surface.
Scientific rewards for the mission will wait for the asteroid sample to return to Earth, but Lauretta said Thursday that scientists are already learning about Bennu’s physical properties.
Shortly after arriving on the asteroid in December 2018, the spacecraft detected small particles flying away from Bennu, which look similar to peeled material leaking out of TAGSAM’s head.
“It looks like a box of corn flakes in space,” Lauretta said. “And they are fluttering around in random motion. Most of the time they come out of the TAGSAM heads, but they collide with each other. They are spinning and falling. It can solve many problems.
“So it’s a great set of imaging calibration data to better understand the particle trajectory observed in the particle emission event and the full encounter with the asteroid,” Lauretta said. “I lost the sample and it hurt my heart, but it was a pretty cool science experiment.”
The October 20 contact of the asteroid surface with OSIRIS-REx also provides a rich data set, suggesting that the asteroid’s soil and the outer layers of low-density rocks do not have much cohesiveness. The spacecraft’s robotic arm touched the asteroid as the OSIRIS-REx approached 0.2 miles per second (10 centimeters per second), about a tenth of the normal walking speed.
“When the TAGSAM head came in contact with Legolis, it ran out like a liquid,” Lauretta said. “And I think if an astronaut tries to walk on the surface of an asteroid it will. She knelt or sunk deeper, depending on how loose the soil was until she hit a larger rock or some sort of bedrock. “
He said the “factual information” data collected by OSIRIS-REx will help scientists rethink the asteroid geology model.
“It’s amazing that there is little resistance to spacecraft on the surface of the asteroid,” Lauretta said. “It’s basically like a ball pool in a children’s playground. You jump into it and just sink.
“Fortunately, we may have a thruster that retreats to change the direction of movement, or we may have blown the asteroid all the way,” lauretta joked.
OSIRIS-REx’s new asteroid density measurement will help scientists refine their assessment of Bennu’s potential impact risk on Earth. Scientists have calculated that Bennu is 1 in 2,700 likely to hit Earth in the late 2100s.
Most of the asteroids can burn out in Earth’s atmosphere due to their porosity.
“Thermal analysis shows that many of the materials on Bennu’s surface, especially the large black hummoky rocks, which are the major constituents of the surface, seem to have material properties that do not damage through the atmosphere,” Lauretta said. . “They will be fragmented and a lot of data will be lost.”
In other words, the primitive specimens collected by Bennu differ from fragments of meteorites or asteroids that fell to Earth and reached intact on the surface.
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