NASA's first asteroid-sampling mission has arrived at its destination after completing a 27-month journey that covered 1.2 billion miles (2 billion km). The Origins, Spectral Interpretation, Resource Identification, Security-Regolith Explorer (OSIRIS-REx) spacecraft arrived at the asteroid Bennu on December 3 to begin flyovers of its north pole, equatorial region and south pole.

These flybys will continue until December 31 as OSIRIS-Rex travels to within 4.3 miles (7 km) of Bennu to document the asteroid’s mass and precise shape before slipping into orbit around the asteroid. Data gathered by studying the 1,650-foot-wide (500 m) asteroid will help NASA researchers select optimal sites for the collection of two ounces (60 g) of dirt and rocks.

The sample-collection maneuver for the $800 million mission is scheduled to occur in July 2020. If all goes according to plan, OSIRIS-REx will depart Bennu in March 2021, and the sample will come down to Earth in a special return capsule in September 2023. Researchers will then analyze the material, searching for clues about the early history of the solar system. The data could shed light on the resource potential of Bennu-like asteroids, providing information of interest to space miners and the manned spaceflight community.

The mission data should also help scientists better understand how solar heating can affect asteroids' paths through space, leading to more accurate predictions of where potentially hazardous space rocks may be headed. There is a very slight chance that Bennu could strike Earth in the late 22nd century.

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