NASA’s OSIRIS-REx was so good at grabbing asteroid rocks that are overflowing

NASA’s OSIRIS-REx spacecraft did its job too well Tuesday, when it tried to collect a handful of rocks from an asteroid named Bennu more than 200 million miles from Earth. The vehicle really grabbed too material with his robotic arm, jamming the cap onto the end of the open arm and letting some of the asteroid sample escape into space.

“We were almost victims of our own success here,” Dante Lauretta, the principal investigator for the OSIRIS-REx mission at the University of Arizona, told a news conference.

OSIRIS-REx’s mission is to bring a sample of asteroid material to Earth so that scientists can study the rocks in a laboratory. But because OSIRIS-REx bit off more than it could chew, its mission team is racing to store the sample inside the belly of the spacecraft, so the rover doesn’t lose too much material in a vacuum. “Time is of the essence and no, we will not sleep,” said Thomas Zurbuchen, NASA associate administrator for science, at a news conference.

The good news is that OSIRIS-REx appears to have taken over an abundant and diverse group of asteroid rocks. The team’s goal was to catch up to 60 grams (2.1 ounces) of rocks from Bennu’s surface, and images from the spacecraft show that OSIRIS-REx likely grabbed up to 400 grams (14.1 ounces) of material, according to the mission team. The sample includes rocks that vary in size, and some are so large that they prevented the spacecraft from sealing the sample.

Image: NASA

The engineers are confident that the rocks don’t escape too quickly, so the spacecraft should be able to store a good amount inside the spacecraft before it gets too depleted. They believe that yesterday they lost between 1 and 10 grams of material, after moving the robotic arm. However, NASA does not plan to store the sample inside OSIRIS-REx until Monday. The mission team has to take the time to figure out all the spacecraft’s commands and make sure this process still works with rocks spilling into space. It is unclear how much of the sample will be lost while they wait.

There is also another complication: simply moving the robotic arm with the sample in makes the rocks flee outwards, so storing the materials risks losing more pebbles. Engineers believe they can lose up to 10 more grams of rock simply by storing the sample inside the spacecraft. But you better save something to wait for everything to leak.

To take the sample from Bennu, OSIRIS-REx is equipped with a robotic arm that has a cylindrical sample collector on the end. On Tuesday afternoon, OSIRIS-REx slowly approached Bennu and tapped its surface with the collector. At the moment of contact, the collector blew out a lot of nitrogen gas, shaking all the rocks and pebbles from the asteroid’s surface. Some of those rocks shot into the collector, while others danced and spun into space.

The OSIRIS-REx team couldn’t immediately say whether they had a sample or not, as they had to wait to get images of the spacecraft. But they soon learned they had a problem when they finally got a close-up image of the sample collector. The pictures show that part of the cap is stuck one centimeter; Small chunks of asteroid can be seen floating around the arm.

If the sampling had been smoother, NASA would have waited a little longer to store the material inside OSIRIS-REx. In fact, the mission team had planned to do a turning maneuver on Saturday with the spacecraft, spinning the vehicle with its extended robotic arm. This would have helped the team determine how much material the spacecraft had collected. Engineers were able to measure the inertia of the spacecraft, comparing it to an earlier time when the spacecraft did not have a sample on its arm. But the turn is effectively canceled. “You would run the risk of losing material, so it is not a prudent path to take,” said Lauretta.

That means the OSIRIS-REx team won’t really know how much sample is in the belly of the spacecraft when the rover returns to Earth. “I think we will have to wait until we get home to know precisely how much we have and that, as you can imagine, that is difficult,” said Lauretta. “We were waiting for a mass measurement sample.” So it’s possible that the entire sample will drop before Monday, and we won’t really know until the spacecraft returns to our planet.

The OSIRIS-REx team is also not planning to take another sample from Bennu, so this is it. That’s why engineers are working quickly to store this sample on Monday. “I am very sure it was a success, that we have more than the 60 grams of material that we promised Thomas and the agency that we would deliver,” said Lauretta, adding that “the most important thing is to store the sample safely and minimize more losses “.