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OSIRIS-REx: A Journey to Asteroid Bennu and Back


NASA's OSIRIS-REx (Origins, Spectral Interpretation, Resource Identification, and Security – Regolith Explorer) is the first U.S. mission to collect a sample from an asteroid and return it to Earth. Launched on September 8, 2016, the arrived at asteroid Bennu in December 2018 and collected a sample from its surface on October 20, 2020. The mission aims to deliver the largest asteroid sample ever received on Earth, estimated to hold about half a pound of Bennu's material or 8.8 ounces +/- 3.6 ounces (250 grams +/- 101 grams).

Sample Return and Recovery

On September 24, 2023, OSIRIS-REx is scheduled to deliver its sample of asteroid Bennu to Earth. The Sample Return Capsule (SRC) will touch down in the Utah western desert within a 37-mile by 9-mile ellipse (58 km by 14 km) within the Department of property at the Utah Test and Training Range and Dugway Proving Ground.

Studying the Samples

Once the sample arrives on Earth, it will be transported to NASA's Johnson Space Center. Over the next two years, the and curation teams will catalog the sample and conduct the analysis needed to meet the mission's science goals. Approximately six months after the return, a sample catalog will be released, and samples from Bennu will be made available for by scientists around the world for decades to come.

NASA's Johnson Space Center curation lab will distribute portions of the asteroid Bennu sample to a sample analysis team of more than 200 members from over 35 globally distributed institutions. The OSIRIS-REx sample will be distributed as follows:

  • The team will have access to about 25% of the returned sample to achieve the mission's science goals.
  • 4% of the total returned sample will be delivered to the (), which contributed the OSIRIS-REx Laser Altimeter (OLA) instrument aboard the spacecraft and supports the Canadian co-investigators on the OSIRIS-REx science team.
  • 0.5% of the total returned sample will be delivered to the Aerospace Exploration Agency () as part of a partnership between the two that includes NASA support for the Hayabusa2 mission and the exchange of scientists and samples between the two missions.
  • A portion of the Johnson-curated material will be sent to a secure backup facility in White Sands, New Mexico, similar to the procedure followed for the Apollo rocks.
  • The remainder of the sample will be publicly available for analysis by request by scientists around the world and curated such that a large fraction will be stored and available to future generations of researchers.

Scientific Goals and Importance of Bennu

Asteroid Bennu is a well-preserved 4.5-billion-year-old remnant of our early . Scientists believe a sample from Bennu will help them learn how our solar system and planets evolved. Bennu is a carbon-rich, near-Earth asteroid that serves as a time capsule from the earliest history of our solar system. A sample of a carbonaceous asteroid will help scientists investigate planet formation and the origin of organics that may have led to life on Earth.

NASA researchers chose to study asteroid Bennu for two main reasons: (i) it's rich in carbon, meaning it could contain the chemical building blocks of life, and (ii) every few years, Bennu flies relatively close to Earth, crossing Earth's orbital path, making it accessible to a mission like OSIRIS-REx. Additionally, it has a (very small) chance of hitting Earth next century, meaning studying Bennu can help us learn how to be prepared to defend against an impact.



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