Osiris-rex bennu asteroid

NASA's OSIRIS-REx mission collected samples from asteroid Bennu and returned them to Earth in 2023.

About this subject

The OSIRIS-REx mission (Origins, Spectral Interpretation, Resource Identification, Security, Regolith Explorer) was launched by NASA on September 8, 2016, with the goal of studying the near-Earth asteroid Bennu and collecting a sample from its surface. After a two-year journey, the spacecraft arrived at Bennu in December 2018 and spent over two years mapping the asteroid in detail to select a safe collection site. On October 20, 2020, OSIRIS-REx performed the Touch-And-Go (TAG) maneuver, extending its robotic arm to touch Bennu's surface for just a few seconds, releasing nitrogen gas to lift particles and store them in the sample container. The operation was a success, collecting approximately 250 grams of regolith, far more than the planned minimum of 60 grams.

Bennu is a carbonaceous B-type asteroid with an average diameter of about 490 meters, classified as potentially hazardous due to its orbital proximity to Earth. It is rich in carbon and organic compounds, including amino acids and nitrogenous bases, molecules essential for life as we know it. Therefore, analysis of the sample could provide clues about the formation of the Solar System and the origin of life on Earth. Additionally, studying Bennu helps refine planetary defense models, as the asteroid has a small probability of impacting Earth in the 22nd century.

The return journey of OSIRIS-REx began in May 2021, and the sample capsule landed in the Utah desert, United States, on September 24, 2023. Since then, scientists worldwide have been analyzing the material in specialized laboratories, already identifying water and organic compounds. The mission has also left a legacy of scientific data on asteroid geology and composition, serving as a precursor for future sample return missions, such as Mars Sample Return.

Frequently Asked Questions

What is the OSIRIS-REx mission and what was its main goal?

OSIRIS-REx was a NASA mission to study asteroid Bennu and collect a sample from its surface, returning it to Earth for analysis. The main goal was to understand the composition of primitive asteroids and investigate the origin of life in the Solar System.

Why was asteroid Bennu chosen for this mission?

Bennu is a carbonaceous asteroid rich in organic compounds and water, potentially containing precursor molecules to life. Additionally, its near-Earth orbit makes it accessible and relevant for planetary defense studies.

What are the main results of the mission so far?

The collected sample contained more material than expected, and initial analyses revealed the presence of water and organic compounds. The data also improved knowledge about asteroid structure and history, as well as calibrated impact risk models.