Osiris-Rex is a near-Earth asteroid sample return mission. The NASA spacecraft was launched on 8 September 2016 on an Atlas V rocket. Heading to asteroid Bennu.

Osiris-Rex Picture

What is Osiris-Rex?

Osiris-Rex is a spacecraft NASA is sending a space probe to near earth asteroid Bennu.

Astronomers have found that the asteroid Bennu crosses Earth’s orbit once every six years and is getting closer. In 2135 it will pass between the moon and earth. According to scientists the chance of an Earth impact is small.

What is Osiris-Rex Name Stand for?

Osiris-Rex stands for the Origins Spectral Interpretation Resource Identification Security – Regolith Explorer.

Osiris-Rex Atlas V Picture


  1. To map every detail of the asteroid Bennu. It will descend and hover about the surface to pick up some rubble before returning to Earth.
  2. To study the geology of asteroid Bennu.
  3. To assist scientists investigate how planets formed and how life began.
  4. To help improve our understanding of asteroids that could impact Earth.
  5. To study and measure the Yarkovsky effect.

The Yarkovsky effect is a force on an asteroid when it absorbs sunlight and then radiates it back into space as heat. It acts like a small thruster, constantly changing an asteroid’s course. As of 2016 Bennu’s position has shifted 160km since 1999.


Osiris-Rex spacecraft is being built by Lockheed Martin Space Systems in Denver, USA.

Overall mission management is provided by NASA’s Goddard Space Flight Center in Greenbelt, Maryland, USA.


Osiris-Rex spacecraft was launched on 8 September 2016 on an Atlas V rocket from Space Launch Complex (SLC)-41 at Cape Canaveral Air Force Station, Florida.

OSIRIS-REx was the 65th launch of an Atlas V and the fourth in the 411 configuration. 411 configuration adds a single strap-on solid booster rocket to the first stage.

This was United Launch Alliance’s (ULA) 111th launch since the company was formed in 2006.


Mass (without fuel): 880 Kg (1,940 pounds)
Mass (fueled): 2110 Kg (4,650 pounds)
Length: 6.2 m (20.25 ft) with solar arrays deployed
Width: 2.43 m (8 ft)
Height: 3.15 m (10.33 ft)

Asteroid Bennu

Asteroid Bennu is a carbonaceuos near Earth Asteroid. It was formerly called 1999 RQ36. The asteroid was discovered in 1999 and has been studied intensively partly because of the potential threat it poses to earth and also due to its huge scientific interest.

Bennu is about 488 metres in diameter and travels around the sun at an average of 101,000kph.

Bennu is an ancient relic from the early solar system that is filled with organic molecules. Asteroids like Bennu may have seeded the early Earth with organic molecules.

Extra info

Gravity of Bennu is so small, forces like solar radiation and thermal pressure from Bennu’s surface can push the spacecraft around in its orbit much more than if it were orbiting around Earth or Mars.

Mission History

September 2016: Launch of Osiris-Rex spacecraft.

The spacecraft’s journey involves an initial year of orbiting the sun to build up speed before it slingshots back around the earth. It will use Earth’s gravity to align its orbit with the asteroid Bennu.

August 2018: Osiris-Rex spacecraft arrives at asteroid Bennu to start a year-long detailed survey.

December 2018: NASA’s OSIRIS-REx spacecraft went into orbit around asteroid Bennu for the first time on 31 December 2018.


July 2020: Osiris-Rex spacecraft descends to the surface to recover up to 5 pounds of rocks. When its scoop hits the surface a blast of gas should force material into its collector.

September 2023: Osiris-Rex flies back to Earth and returns samples.

Did you know?

  • OSIRIS-REx is the third mission in NASA’s New Frontiers Program. New Horizons was the first mission and Juno was the second mission.
  • Earth has been hit by asteroids and meteorites many times in the past. There are theories that an Earth-Asteroid collision formed our Moon and an asteroid may have wiped out the dinosaurs.
  • Asteroids have featured in many films such as Armageddon movie and Deep Impact movie where they try to save Earth.
  •  The Atlas V rocket uses a Russian-built RD-180 to power its first stage and an American-built RL10 engine to power its Centaur upper stage.

Osiris- Rex Links:

OSIRIS-REx Mission: Home
NASA’s OSIRIS-REx Spacecraft Enters Close Orbit Around Bennu, Breaking Record:
By Lonnie Shekhtman (asteroidmission.org)

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