
A replica of the OSIRIS-REx sample return capsule descends under parachute during a dress rehearsal Aug. 30 in Utah. (NASA/Keegan Barber)
Bits of pebbles and dust from the asteriod Bennu that were collected during the long journey of the OSIRIS-REx spacecraft should be landing in the Utah desert later this month.
The delivery will be a first for NASA — its first sample return from an asteroid and one of a very small handful of space objects ever brought to Earth by humans from anywhere but the moon.
The roughly two ounces (60 grams) of regolith collected from the surface of Bennu — a 4.5 billion year old remnant of the early solar system — are expected to give new insights into how our solar system planets were formed and about the mix of organic compounds present when life began on Earth.
The landing will be the finale to a quite remarkable 4.7 million mile journey to, around and onto a tiny ball of dirt, gravel and pebbles, and then back to Earth. The spacecraft studied the asteroid from close orbit for almost two years before making its hazardous touch-and-go attempt to scoop up some regolith.
Though successful, that contact was a lot more fraught than expected. The asteroid is held together by only very week gravitational forces, the scientists found, and it nearly swallowed OSIRIS-REx as a swamp would, kicking up a wall of debris into space that threatened the spacecraft’s safety.
Now comes the final challenge of the return capsule drop-off. Once on Earth, the samples will go to NASA’s Johnson Space Center for curating, examining and ultimately distributing to scientists for their long-awaited chance to learn up close about a celestial body untouched by the teeming biosphere of Earth.

The steroid Bennu, as imaged from about 15 miles away by OSIRIS-REx, the Origins-Spectral Interpretation-Resource Identification-Security-Regolith Explorer. (NASA)
The returning asteroid sample from Bennu is not the first of its kind to be flown to Earth — that honor goes to the Hayabusa and Hayabusa2 spacecraft sent by the Japan Aerospace Exploration Agency. They returned with bits of dust and soil from two other asteroids, Ryugu (2020) and Itokawa (2010.)
Like Bennu, Ryugu is a carbonaceous asteroid, with a material makeup that includes substantial carbon. These are the type of asteroid most common in the solar system and of the most interest to space scientists since they generally contain the organic (i.e,… Read more