WASHINGTON – NASA’s OSIRIS-REx spacecraft has secured material collected from the asteroid Bennu into a sample return capsule, a process that the mission accelerates after images show material leaking into the air. time.
At a briefing on October 29, project officials said they had loaded a sample collection device called the Induction and Movement Collection Mechanism (TAGSAM) into a capsule on board the spacecraft. pillar. A robotic arm moved the TAGSAM head to the inside of the capsule, then closed.
That TAGSAM tip touched the surface of the asteroid Bennu on October 20 in a matter of seconds and appeared to have obtained a large amount of matter. However, October 23 officials said TAGSAM had collected too much material, a Mylar cap designed to seal the material in place was inserted by several large rocks, causing some The material is leaked out, as shown in images from a spacecraft.
NASA then decided to accelerate the process of placing TAGSAM in a capsule that would return the material back to Earth, bypassing the weighing of the sample. The controllers spent around 36 hours on October 26 and 27 using the robotic arm to move the TAGSAM head into place in the return capsule and verify that it was locked in place, then sealed. capsule capsule.
“Stow is a period of intense activity. Our fleet has been working around the clock to accomplish these in a much shorter amount of time than we had envisioned, ”Sandra Freund, OSIRIS-REx Mission Executive Manager at Lockheed Martin said. Another complication is the spacecraft̵7;s distance from Earth, with a journey time around more than half an hour.
That archiving was originally scheduled for early November, so moving it up means securing time on the Deep Space Network (DSN) away from other users. “There have been a lot of last minute renegotiations with several missions,” said Lori Glaze, NASA’s director of planetary science.
Dante Lauretta, the mission’s lead investigator at the University of Arizona, said he believes that, despite the leaking material, there is still a large amount of material in TAGSAM’s head when it is sealed inside the capsule. “We have continued to analyze the images and estimate that tens of grams of sample may have escaped over the entire sequence,” he said.
The accelerated queuing process means that the project skipped the rotation of the spacecraft slowly, measured the change in its moment of inertia compared to before the sampling test and thereby estimated the mass of the matter. obtained from asteroids. That action can cause more matter to escape.
However, Lauretta said he believes the spacecraft has retained more matter than its target of 60 grams. He said the image inside the head showed at least 400 grams of matter. He added those images covered only 17% of the TAGSAM player’s volume. “Wherever we can see TAGSAM, we can see many patterns there,” he said. “We are probably having a kilo of excess material.”
There may be other ways to estimate the mass of the material, such as the way a robot arm moves during the queue. “We definitely want an estimated sample mass before 2023,” when the spacecraft returns to Earth, says Freund.
The scientists analyzed images taken during and after sampling attempts to better understand the surface. Material leaked out of TAGSAM, he says, has a “flaky” appearance. “Looks like you dumped a box of cornbreads into space, and they’re flying around, in random motion,” he says.
Bennu’s surface itself is quite weak. The TAGSAM head plunged as deep as half a meter to the surface in its brief encounter. “Basically, there is almost no force between the particles holding them together. They don’t stick together in any way, ”Lauretta said. If an astronaut stepped onto the surface, “she would kneel or go deeper, depending on the looseness of the soil, until you hit a larger rock or some sort of platform.”
However, plunging deep may allow OSIRIS-REx to collect material from below the surface. Such material would be protected from sunlight and richer in volatile matter, he said.
With the samples collected by Bennu securely inside the return capsule, the task is now focused on returning those samples back to Earth. The window for the maneuver of the spacecraft to depart the vicinity of Bennu will open in early March 2021. Rich Burns, the project manager of OSIRIS-REx at NASA’s Goddard Space Flight Center, tells know the opportunity for that movement to last through May. Maneuver departure will return the spacecraft to Earth in September 2023.