ON THIS PAGE
Dec. 3, 2018: NASA’s OSIRIS-REx completed its 1.2 billion-mile (2 billion-kilometer) journey to arrive at the asteroid Bennu Monday. The spacecraft executed a maneuver that transitioned it from flying toward Bennu to operating around the asteroid.
Now, at about 11.8 miles (19 kilometers) from Bennu’s Sun-facing surface, OSIRIS-REx will begin a preliminary survey of the asteroid. The spacecraft will commence flyovers of Bennu’s north pole, equatorial region, and south pole, getting as close as nearly 4 miles (7 kilometers) above Bennu during each flyover.
The primary science goals of this survey are to refine estimates of Bennu’s mass and spin rate, and to generate a more precise model of its shape. The data will help determine potential sites for later sample collection.
Asteroids are rocky, airless worlds that orbit our Sun, but are too small to be called planets. Tens of thousands of these minor planets are gathered in the main asteroid belt, a vast doughnut-shaped ring between the orbits of Mars and Jupiter. Asteroids that pass close to Earth—and merit close watch—are called Near-Earth Objects, or NEOs.
The current known asteroid count is: .
Go farther. Explore Asteroids In Depth ›
Did You Know?
The total mass of all the asteroids in the main asteroid belt combined is less than that of Earth's Moon.