By- srushti sharma
Seven years after the mission's launch, a NASA spacecraft carrying the largest soil sample ever taken from an asteroid's surface landed in the Utah desert.
Nearly 400kg (842lbs) of moon rocks that the Apollo astronauts collected more than 50 years ago are already housed in the structure.
Until the container is opened, scientists can only guess how much debris from the carbon-rich asteroid known as Bennu is contained inside.
The only other nation to return samples from an asteroid was Japan, which collected around a teaspoon from two asteroid trips.
Dante Lauretta of the University of Arizona, the mission's principal investigator, will go to Texas with the samples.
Given the ambiguity surrounding the contents, he said before landing that the container's opening in Houston in a day or two would be "the real moment of truth."
The sample for OSIRIS-REx was taken from the tiny asteroid Bennu three years ago. Bennu was found in 1999.
The space rock is categorised as a "near-Earth object" since it orbits our planet every six years, passing relatively close to it. The likelihood of an impact is regarded as remote.
Scientists will look for clues about the solar system's early days, which may be locked away inside the ancient, primitive asteroid