On Tuesday, Oct. 20, the OSIRIS-REx spacecraft touched down on the asteroid Bennu for 4.7 seconds, a maneuver that was more than a decade in the making. Scientists at the University of Arizona nervously watched the data from the autonomous process — because the asteroid is more than 200 million miles away, messages from the spacecraft take some 20 minutes to reach Earth, meaning the entire maneuver had to be programmed ahead of time. Preliminary data shows the "touch-and-go" process was a success, putting OSIRIS-REx one step closer to being the first American space mission to bring a sample of an asteroid back to Earth.
"It's amazing just how fast it happened," said Sara Knutson, science operations team lead engineer for the mission. "It was like a marathon that turned into a sprint."
The OSIRIS-REx spacecraft left Earth in September 2016 with the goal of capturing carbon-rich material from Bennu's surface, which may help scientists better understand the formation of our early solar system, and even the origins of life on our planet.
The sample process took more than four hours, with the spacecraft slowly descending 2,500 feet from orbit toward the asteroid. While the spacecraft came in contact with the asteroid, it didn't land. Instead, it extended a robotic arm and fired a jet of pressurized nitrogen to kick up dust from the asteroid's surface. Some of the agitated material was captured in OSIRIS-REx's collector head, and the spacecraft then used thrusters to move away from the asteroid. Scientists believe the spacecraft touched the surface only three feet from where they originally planned.
However, the team became concerned when the mylar flap on the collection bag appeared to be jammed with larger rocks and some material was leaking, so they decided to stow the sample sooner than expected.
"The abundance of material we collected from Bennu made it possible to expedite our decision to stow," said Dante Lauretta, OSIRIS-REx principal investigator. "The team is now working around the clock to accelerate the stowage timeline, so that we can protect as much of this material as possible for return to Earth."