Scientists chose Bennu as the target of the OSIRIS-REx mission because of its composition, size, and proximity to Earth. Bennu is a rare B-type asteroid (primitive and carbon-rich), which is expected to have organic compounds and water-bearing minerals like clays.


Bennu Facts:

Equatorial Diameter: ~500 m

Polar Diameter: ~510 m

Average Speed: 63,000 mph

Rotation Period: 4.3 hrs

Orbital Period: 1.2 yrs

Orbital Inclination: 6 degrees

Earth Approach: Bennu comes close to Earth every 6 yrs


Primitive asteroids have not significantly changed since they formed nearly 4.5 billion years ago. Because of this, we hope to find organic molecules on Bennu like those that may have led to the origin of life on Earth.

Learn more and watch the story of Bennu’s Journey.

3D OBJ and STL files of the original shape model, preliminary shape model, and 75-centimeter shape model are available for download.