NASA's OSIRIS-REx (Origins, Spectral Interpretation, Resource Identification, Security-Regolith Explorer) mission executed the first asteroid approach maneuver that day, putting the spacecraft on track for its arrival at asteroid Bennu in December, NASA said in a statement. However, it will take at least until next week to find out if the maneuver was successful, NASA said.
OSIRIS-REx performed a braking maneuver using its main engine thrusters. The procedure was designed to slow down the spacecraft to 313 mph (140 meters/second), roughly a third of the craft's previous speed of 1,100 mph (491 m/s).
The engine burn marks the beginning of a busy six weeks for the spacecraft as it completes a series of orbital tweaks that will ensure it reaches its destination.
The last of those maneuvers, scheduled for Nov. 12, will put OSIRIS-REx on track to arrive at Bennu on Dec. 3, at a distance of 12 miles (20 kilometers) from the asteroid's surface. OSIRIS-REx will then do several flybys over Bennu's poles and equator. The mission's ultimate goal is to pick up a sample of the asteroid to return to Earth in 2023.
Meanwhile, the Hayabusa2 sample-return spacecraft successfully dropped the MASCOT (Mobile Asteroid Surface Scout) lander, a joint project of the German and French space agencies, onto the surface of asteroid Ryugu on Oct. 2. There, the lander completed a 17-hour work session. Hayabusa2 will do multiple scoops of the surface itself before returning to Earth with the precious material in 2020.
There's a second, less benign reason to be interested in asteroids: Some of these space rocks, including both Ryugu and Bennu, occasionally cross the orbit of Earth. And scientists would like to be able to better assess how to protect the planet against an unlikely but possible asteroid impact. NASA tracks many thousands of asteroidsthrough its Near-Earth Object program; no imminent threat to Earth has been found yet.