On Wednesday, NASA was prepared to offer the public a first glimpse into the contents of a tightly sealed canister that recently returned to Earth, carrying the most extensive soil sample ever collected from the surface of an asteroid. The material retrieved by the OSIRIS-REx spacecraft, three years ago, from the near-Earth asteroid Bennu, was scheduled for presentation at NASA’s Johnston Space Center in Houston. This unveiling occurred just over two weeks after the capsule parachuted into the Utah desert, marking the conclusion of a six-year collaborative mission between the U.S. space agency and the University of Arizona. This event marked only the third instance of an asteroid sample, and notably the largest one, being brought back to Earth for analysis. Two prior missions by Japan’s space agency in 2010 and 2020 achieved similar feats.
Bennu, like other asteroids, is a relic from the early days of the solar system. Given that its contemporary chemistry and mineral composition remain largely unchanged since its formation some 4.5 billion years ago, it offers valuable insights into the origins and evolution of rocky planets, including Earth, and potentially the development of life itself. Initially, the capsule and its contents underwent examination in a controlled “clean room” near the landing site in the Utah Test and Training Range. Subsequently, the capsule was transported to the Johnson center, where its inner canister was opened, allowing the samples to be divided into smaller portions for distribution to approximately 200 scientists across 60 laboratories worldwide.
At the time of its landing, the Bennu sample was estimated to weigh between 100 to 250 grams (3.5 to 8.8 ounces). NASA was expected to announce a more precise measurement on Wednesday, along with confirmation regarding whether the mission successfully obtained a pristine, uncontaminated sample.
The presentation was also anticipated to reveal physical attributes of the material, such as its density, color, and composition – whether it consists of rocks, pebbles, fine grains, or dust.
The return of samples from the Japanese mission Hayabusa2 in 2020, collected from the Ryugu asteroid, contained two organic compounds, supporting the theory that celestial objects like comets, asteroids, and meteorites played a role in seeding early Earth with the essential ingredients for life.
Bennu, a small carbon-rich celestial body discovered in 1999, is believed to be composed of loosely connected rocks, resembling a rubble pile. It has a diameter of approximately three-tenths of a mile (500 meters), making it slightly wider than the height of the Empire State Building but significantly smaller than the Chicxulub asteroid that struck Earth about 66 million years ago, leading to the extinction of the dinosaurs.
The OSIRIS-REx mission was initiated in 2016 and reached Bennu in 2018, spending nearly two years in orbit around the asteroid before getting close enough to retrieve a sample of the surface material using its robotic arm on October 20, 2020.
On Thursday, NASA is set to launch a separate mission to a more distant asteroid named Psyche, a metallic-rich body believed to be the remnants of a protoplanet’s core. It is recognized as the largest metallic object in the solar system.