A space capsule carrying a sample of rocky material taken from an asteroid is set to make a parachute landing in the Utah desert on Sunday. The sample return is part of the OSIRIS-REx mission, a joint effort between NASA and scientists at the University of Arizona. This mission marks the third asteroid sample, and the largest one, ever returned to Earth for analysis.

The OSIRIS-REx spacecraft was launched in September 2016 and reached its target, the carbon-rich asteroid Bennu, in December 2018. Equipped with cameras, the spacecraft captured images that were crucial for collecting samples from the asteroid's surface. It also developed 3D maps, measured temperature, and mapped mineral and chemical composition, as well as viewed the asteroid in X-rays and infrared light. The spacecraft's robotic arm collected loose rocks and dirt, which were sealed inside the sample return capsule.

The journey back to Earth began in May 2021, covering a distance of 1.9 billion kilometers (1.2 billion miles). The sample is expected to land on Sunday at 14:55 GMT in the Utah Test and Training Range in Utah's West Desert. Scientists will be on standby to retrieve the capsule.

Concerns about potential contamination from the asteroid samples have been addressed. The sample will not contain contaminants such as viruses or bacteria. Harold Connolly, the OSIRIS-REx mission sample scientist, compared the situation to the material taken from Apollo 11 lunar samples. After testing the material on animals and finding no microbial growths, NASA deemed it safe enough to halt further testing and quarantining after the Apollo 14 mission in 1971.

Bennu, also known as 1999 RQ36, is classified as a "near-Earth object" as it passes relatively close to our planet every six years. It is a small asteroid, measuring less than 500 meters in depth, and is estimated to be over 4.5 billion years old. Scientists believe that it has drifted closer to Earth over time and may have a small chance of impacting the Earth in 2182. The mission aimed to better understand the long-term risks of near-Earth asteroids and to study Bennu's chemical composition and potential water content.

Once the sample is retrieved, it will be moved to a clean room at the Utah Test and Training Range before being transferred to a curation facility at NASA's Johnson Space Center in Houston. The sample team expects to announce the first results in October, including Bennu's composition and how it compares to other asteroid samples.

The OSIRIS-REx spacecraft will be repurposed for a new mission named OSIRIS-APEX, which will study another near-Earth asteroid called Apophis. Apophis is predicted to pass by Earth in 2029, providing an opportunity to gather more information and potentially mitigate future encounters with hazardous asteroids.

The landing of the OSIRIS-REx capsule can be watched live on Sunday using the NASA Live link.