Enlarge / This picture, taken Wednesday, shows the OSIRIS-REX Touch-and-Go sampling mechanism sampling head extended from the spacecraft at the…
NASA officials confirmed Friday that a test of a key component of space agency’s mission to try an asteroid was successfully completed. On Wednesday, for the first time in more than two years, the OSIRIS-REX spacecraft threw its robot arm and put it through a series of maneuvers to ensure its space value after packing away for launch and a long flight to the asteroid Bennu.
The asteroid sampling mission was launched in September 2016, and spacecraft has since traveled through space to get to an asteroid called Bennu, which has a diameter of about 500 meters. The spacecraft officially arrives at Bennu in about two weeks on December 3, so the missionaries wanted to make sure that the robot arm was functional after stopping for so long.
This arm and its sampling head, known as the Touch-and-Go sampling mechanism or TAGSAM, is crucial for the mission’s goal of collecting at least 60 grams of material from the surface of Bennu and returning this sample to the ground before 2023. The collector will act as something a reverse vacuum cleaner.
NASA has never tried anything like this before – a maneuvering where the arm places the TAGSAM head on the surface of the asteroid. “TAGSAM is about the size of an old air filter in a car,” explained Beau Bierhaus, a scientist from Lockheed Martin, who heads the TAGSAM business and acts as OSIRIS REX mission researcher. Lockheed Martin built the spacecraft for NASA, and one of its engineers thought about the TAGSAM mechanism.
During the assembly operation, a burst of compressed nitrogen gas will be sent from spacecraft to the asteroid’s surface. TAGSAM will then collect dirt and dust particles in the nitrogen phase and store them in a special container while the gas itself can fly. When testing microwaves and vacuum chambers, the sampling arm has collected between 400 and 500 grams during most attempts.
This sampling operation will not take place until July 2020. Before that, OSIRIS-REX will study the asteroid in great detail – map the topology of space rock to a larger resolution than the Earth’s surface. The map of Bennu will be in the order of 5 cm spatial and a few inches vertical resolution, Bierhaus Ars told.
Illustration of NASA’s OSIRIS-REx spacecraft that revolves around the asteroid Bennu.
The Touch-and-Go Trial Mechanism, or TAGSAM, is displayed on the surface of Bennu.
The Touch-and-Go test arm mechanism is tested in the Lockheed Martin plant.
Another image of the TAGSAM arm and spacecraft, for the scale.
TASK testing in environment with reduced gravity provided important information to optimize the hardware design.
Bill Stafford / NASA
Engineer Jim Harris holds his invention, TAGSAM, who will collect a sample of the asteroid by touching the surface and spraying a nitrous bristle to push the regolith into the round test chamber.
The spacecraft will receive this detailed map for the next 18 months or so, with a preliminary survey giving OSIRIS-REx within approximately 7 km of the asteroid’s surface and then two orbital phases that take it down to within about 750 meters from the surface. From there it will be time for a final choice of location and sample selection of repetitions. Researchers will get their expression on the most interesting site to try, but other criteria are ranked higher, including accessibility and the ability to keep spacecraft safe in its approach to Bennu.
NASA has few samples from other worlds in its collections. There are of course their moonstones, gathered during the Apollo mission. It also has pieces of interstellar dust and comet material. The Soviet Union flew three robotic landlords in the 1970s who fetched a few hundred grams of Moon Rocks, and the Japanese space program has flown two asteroid test returns.
So this is not easy. Make sure that the long-lived sampling arm bends their joints is a good first step.