NASA capsule returned to Earth with asteroid soil

A NASA spacecraft capsule carrying the most extensive soil sample ever acquired from an asteroid’s surface has successfully landed in the Utah desert seven years after the mission’s commencement. The capsule, having a gumdrop-like shape, was released from the robotic spacecraft OSIRIS-REx as the mothership passed within 108,000 kilometres (67,000 miles) of Earth a few hours before landing. It settled within a designated landing area located west of Salt Lake City, situated in the vast Utah Test and Training Range operated by the United States military.

Today, the samples will be transported to a new laboratory at NASA’s Johnson Space Center in Houston. This facility already houses almost 400 kilograms (842 pounds) of moon rocks collected by Apollo astronauts over half a century ago.

Scientists estimate that the capsule contains at least a cupful of debris from the carbon-rich asteroid known as Bennu, but the exact amount won’t be confirmed until the container is opened. OSIRIS-REx collected its specimen from Bennu three years ago.

Bennu is a small asteroid discovered in 1999 and is categorized as a “near-Earth object” because it periodically passes relatively close to our planet, although the odds of an impact are remote. The asteroid is believed to be composed of loosely connected rocks, resembling a rubble pile. It measures 500 meters (1,600 feet) in diameter, slightly larger than the height of the Empire State Building but still small compared to the Chicxulub asteroid, which struck Earth around 66 million years ago, causing the extinction of dinosaurs. Like other asteroids, Bennu is a remnant of the early solar system. Since its formation 4.5 billion years ago, its current chemistry and mineral composition have remained virtually unchanged, providing valuable insights into the origins and evolution of rocky planets like Earth. It may even contain organic molecules similar to those needed for the emergence of life.

OSIRIS-REx was launched in September 2016, reached Bennu in 2018, spent nearly two years orbiting the asteroid, and successfully collected a sample of surface material with its robotic arm on October 20, 2020. In May 2021, the spacecraft departed Bennu for a 1.9-billion-kilometer (1.2-billion-mile) journey back to Earth, including two orbits around the sun.

A recovery team comprised of scientists and technicians were on standby to retrieve the capsule from the landing site and confirm the integrity of both the vessel and the inner canister containing the asteroid material. Their aim was to preserve the sample’s purity and prevent any contamination from Earth.

Japan is the only other nation in the world to have returned samples from an asteroid, having collected about a teaspoon from two asteroid missions. Samples brought back by the Japanese mission Hayabusa2 from Ryugu, another near-Earth asteroid, in 2020, contained two organic compounds, supporting the idea that celestial objects such as comets, asteroids, and meteorites that bombarded early Earth seeded the young planet with the essential ingredients for life.