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NASA
NASA officials confirmed Friday that a test of a key element of the space agency's mission of sampling an asteroid had been carried out successfully. On Wednesday, for the first time in more than two years, the OSIRIS-REx spacecraft deployed its robotic arm and subjected it to a series of maneuvers to ensure its value after being tidied up for launch and a long flight to the asteroid Bennu. .
The asteroid sampling mission was launched in September 2016 and the spacecraft has since crossed the space to catch up with an asteroid called Bennu, whose diameter is about 500 meters. The shuttle will officially "arrive" at Bennu in about two weeks on December 3rd, so the mission scientists wanted to make sure that the robotic arm was functional after being stowed for so long.
This arm and its sampler head, known as the Touch-and-Go or TAGSAM sample acquisition mechanism, play a vital role in the mission's goal of recovering at least 60 grams of material from Bennu's surface and return this sample to Earth by 2023 here. collection device will act something like an inverted vacuum.
NASA has never tried anything like this before: a maneuver in which the arm will place the "head" of TAGSAM on the surface of the asteroid. "TAGSAM is about the size of an old air filter in a car," explained Beau Bierhaus, a Lockheed Martin scientist who heads TAGSAM's operations and is the co-scientific researcher for the OSIRIS mission. REx. Lockheed Martin built the probe for NASA and one of its engineers designed the TAGSAM mechanism.
During the collection maneuver, a compressed nitrogen gas will be sent from the probe to the surface of the asteroid. TAGSAM will then collect the dirt and dust particles raised by the nitrogen gas and store them in a special can while allowing the gas to escape. In the microgravity and vacuum chamber tests, the pick-up arm collected between 400 and 500 grams during most attempts.
This sampling maneuver will not take place until July 2020. Until then, OSIRIS-REx will study the asteroid in a very detailed way, by mapping the topology of the spatial rock with a resolution higher than that from the surface of the Earth. Bennu's map will have a spatial resolution of 5 cm and a vertical resolution of a few cm, said Bierhaus in Ars.
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Illustration of NASA's OSIRIS-REx spacecraft in orbit around the asteroid Bennu.
Lockheed Martin
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The Touch-and-Go Sampling Arm Mechanism, or TAGSAM, is being introduced to the surface of Bennu.
Lockheed Martin
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The Touch-and-Go sampling arm mechanism is tested in Lockheed Martin's facilities.
Lockheed Martin
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Another view of the TAGSAM arm and spacecraft, on the scale.
Lockheed Martin
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TAGSAM tests in a reduced-gravity environment provided important information for the optimization of the hardware design.
Bill Stafford / NASA
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The engineer Jim Harris holds his invention, TAGSAM, which will take a sample of the asteroid by touching the surface and spraying a puff of nitrogen in order to push the regolith into the round chamber of the # 39; sample.
Lockheed Martin
The probe will obtain this detailed map over the next 18 months, with a preliminary study that will bring OSIRIS-REx about 7 km from the surface of the asteroid, then two orbital phases that will bring it back to about 750 meters from the surface. From there, it will be time to make the final selection of the site and the sample selection repetitions. Scientists will have a say in the most interesting site to sample, but other criteria rank higher, including accessibility and the ability to maintain the safety of the spacecraft as it approaches. from Bennu.
NASA has few samples from other worlds in its collections. There are of course its lunar rocks, collected during the Apollo mission. It also contains interstellar dust particles and cometary materials. In the 1970s, the Soviet Union had piloted three robotic undercarriages that had recovered a few hundred grams of lunar rocks. The Japanese space program has also organized two missions to return asteroid samples.
So, it is not easy. Ensuring that the long dormant sampling arm can flex its joints is a good first step.
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