A sample collection from asteroid Bennu — categorized as a "near-Earth object" — is due to land Sunday. Scientists hope the sample will give a greater understanding of how Earth became habitable.
If OSIRIS-REx makes a successful landing, it will mark the third and largest asteroid sample to have ever been brought to Earth in history.
The capsule, launched by NASA in collaboration with the University of Arizona, is scheduled to make a parachute landing at 10:55 am EDT (1455 GMT) in the Utah desert.
The capsule's landing is risky but mission managers at the US space agency said they were hoping for a "spot-on" touchdown.
Why is the OSIRIS-REx mission important?
The mission was launched in September 2016 to collect samples from Bennu, an asteroid rich in carbon and classified as a "near-Earth object."
The capsule landed on Bennu's surface in 2020 and collected about nine ounces (250 grams) of dust from its stony surface.
"This sample return is really historic," NASA scientist Amy Simon told the AFP news agency. "This is going to be the biggest sample we've brought back since the Apollo moon rocks" were returned to Earth.
Scientists believe that by examining the samples, we can gain a better understanding of how our solar system was formed and how Earth became habitable.