Scientists first caught sight of Bennu on Sept. 11, 1999, with a one-meter telescope near Socorro, New Mexico, during the Lincoln Laboratory Near Earth Research (LINEAR) survey. The asteroid was within 0.05 astronomical units of Earth (about 20 times the distance from Earth to the Moon). One astronomical unit is the distance between Earth and the Sun, equivalent to about 93 million miles.

In 1999, scientists collected data about Bennu through radar imaging and ranging from radio telescopes, and through spectroscopy—a technique to explore the composition of an object by examining the kind of light it reflects.

From 2005 to 2007, when it approached Earth again, various space-based and ground-based telescopes observed Bennu. NASA’s Spitzer Space Telescope measured the temperature and brightness of the asteroid in 2008.

NASA’s Hubble and Spitzer space telescopes, the European Space Agency’s Herschel Space Observatory, and a variety of ground-based observatories focused on Bennu again from 2011 to 2012. These observations helped scientists refine its rotation period and shape. Radio observations from 2011, as well as 2005 and 1999, have enabled astronomers to calculate speeds and distances for Bennu at various times.

The asteroid makes one full orbit around the Sun every 1.2 years. Its trajectory takes it relatively close to Earth every six years. Observations from 1999-2000 and 2005-6 were especially fruitful because Bennu was so close. The asteroid won’t make another close approach to Earth until 2060.

NASA’s OSIRIS-REx (Origins, Spectral Interpretation, Resource Identification, Security-Regolith Explorer) mission, which launched in 2016, performed the most in-depth exploration of Bennu to date. During its Oct. 20, 2020, sample collection event, the spacecraft collected a substantial amount of material from Bennu’s surface, likely exceeding the mission’s requirement of 2 ounces (60 grams). The spacecraft is scheduled to deliver the sample to Earth on Sep. 24, 2023.

Significant Events

Significant Events

  • Sept. 11, 1999: The LINEAR survey discovers the asteroid 1999 RQ36.
  • 2005-2006: The asteroid makes a close approach to Earth, and scientists observe it with space-based and ground-based telescopes.
  • 2011-2012: The asteroid makes another close approach. Radio observations and space observations help scientists define its rotation period and model its shape.
  • 2013: A third-grader named Michael Puzio names the asteroid Bennu through a contest.
  • 2014: Scientists calculate the mass of Bennu by measuring its thermal properties and how much it deviates from its predicted orbit—the first time that the mass of an asteroid has been found in this way.
  • 2016: NASA’s OSIRIS-REx spacecraft launches, en route to study Bennu up close and return a sample.
  • 2018: OSIRIS-REx approached Bennu and began to map its surface.
  • 2020: OSIRIS-REx collected a sample of material from Bennu’s surface.
  • 2023: OSIRIS-REx will return to Earth with the sample from Bennu.


10 Careers That Explore Space



Astronauts pave the way for human exploration beyond our Earth. They are pilots, scientists, engineers, teachers, and more.


Project Manager

Project managers guide missions from concept to completion, working closely with team members to accomplish what they set out to do.  


Rover Camera Operator

A camera payload uplink lead writes software commands that tell a rover what pictures to take.

The first thing that fired my imagination for planetary science was when the NASA Voyager spacecraft discovered active volcanoes on Jupiter's moon Io.



Melding science with design, artists create everything from large-scale installations to the NASA posters hanging in your bedroom. 


Media Specialist

Media specialists tells stories across social media and help feature missions and people on TV and in films, books, magazines, and news sites. 



Writers/producers capture the incredible stories of NASA's missions and people and share them with the world. 



Administrators and directors work out of NASA headquarters, prioritizing science questions and seeking to expand the frontiers of discovery.



Whether it's introducing kids to space or teaching physics to PhD candidates, educators help share their knowledge with the public.



Engineers design and build all types of machines, from what a spacecraft looks like to the software that directs where a rover goes each day. 



From an astrophysicist to a volcanologist, scientists of all types pose questions and help find answers to the mysteries of our universe.

The important thing about being a scientist or an engineer is learning how to think critically, learning how to be creative, learning problem solving and learning how to learn.

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