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    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.

    Animated GIF of asteroid growing larger
    This series of images taken by the OSIRIS-REx spacecraft shows asteroid Bennu in one full rotation from about 50 miles (80 km). Credit: NASA's Goddard Space Flight Center/University of Arizona

    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 ›

    Key Science Targets

    Did You Know?

    Did You Know?

    The total mass of all the asteroids in the main asteroid belt combined is less than that of Earth's Moon.

    Kid-Friendly Asteroids

    Illustration of asteroids

    Kid-Friendly Asteroids

    Asteroids are small, rocky objects that orbit the Sun. Although asteroids orbit the Sun like planets, they are much smaller than planets.

    There are lots of asteroids in our solar system. Most of them live in the main asteroid belt—a region between the orbits of Mars and Jupiter.

    Some asteroids go in front of and behind Jupiter. They are called Trojans. Asteroids that come close to Earth are called Near Earth Objects, NEOs for short. NASA keeps close watch on these asteroids.

    Asteroids are left over from the formation of our solar system.

    Visit NASA Space Place for more kid-friendly facts.

    NASA Space Place: All About Asteroids ›

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