NASA OSIRIS-REx spacecraft breaks record with asteroid orbit

On New Year's Eve, while the rest of the world was celebrating the approach of 2019, NASA's OSIRIS-REx spacecraft broke a new record after successfully entering into the closest orbit to ever take place. The milestone event involved the asteroid Bennu, a relatively small space rock located about 70 million miles from Earth. According to NASA, this is the smallest object to ever be orbited by a spacecraft.

The space agency announced its success on New Year's Eve, explaining that it took only a single 8-second burn from OSIRIS-REx's thrusters to get into orbit. This marks the first time humanity has managed to put a spacecraft into such a close orbit around such a small so small that the gravity is barely sufficient enough for a stable orbit.

The spacecraft is orbiting Bennu only about one mile from the asteroid's center. NASA describes its vehicle's orbit as happening "at a snail's pace." Because Bennu's gravity is only around "5-millionths" as strong as our own planet's, OSIRIS-REx must maintain such a close orbit to keep stable. A single orbit takes 62 hours to complete; the mission will run through mid-February.

The very close orbit will enable OSIRIS-REx to take very detailed images of the asteroid's surface, which NASA describes as a "rubble pile of primordial debris." The spacecraft first arrived at Bennu earlier this month, when it made a few observations and sent back a couple images of the space rock. Among other things, researchers have already noted signs of ancient water on the asteroid.

According to the space agency, OSIRIS-REx's team will need to make occasional adjustments to ensure the spacecraft stays in the asteroid's orbit. This includes what are called "trim maneuvers," which are slight thrusts to counteract small forces and maintain orbit.

In the event OSIRIS-REx does lose its orbit, though, NASA explains that it was programmed to simply fly away from the asteroid to avoid an accidental impact. Once safely at a distance, the vehicle's team will be able to assess the situation and eventually put the spacecraft back into orbit again.

The orbit will complete multiple phases of the overall mission, gathering images and vital data on Bennu. All of this leads up to a planned short touchdown and sample collection from the asteroid's surface scheduled to happen in 2020.