OSIRIS-REx and Bennu: Bringing Asteroid Dust Home

The mission at a glance

OSIRIS-REx spent nearly two years at Bennu before it took the sample, and scientists worldwide are still analyzing the material it returned. The main dates are below.

• September 8, 2016: OSIRIS-REx launches from Cape Canaveral, Florida.
• December 3, 2018: the spacecraft arrives at Bennu. It enters orbit for the first time on December 31, 2018.
• October 20, 2020: the touch-and-go sample collection happens.
• September 24, 2023: the sample capsule lands in Utah.
• October 11, 2023: NASA announces the first look at the sample.
• February 15, 2024: the total bulk sample reaches 121.6 g.

For how Bennu fits among other asteroid types, see the guide to what asteroids are. Bennu is also part of the group studied in the article on near-Earth asteroids.

NASA says Bennu's rocks formed nearly 4.6 billion years ago, and the asteroid itself coalesced from leftover rubble about 1 billion to 2 billion years ago. It may have formed in the main asteroid belt between Mars and Jupiter and drifted toward Earth afterward. The team picked a sample site inside a crater called Nightingale, about 140 m (460 feet) wide.

The touch-and-go grab

The sample was gathered in a maneuver called touch-and-go, shortened to TAG. The spacecraft did not land. It descended slowly on October 20, 2020, and its sampling arm touched the surface only briefly.

The sequence took hours. After leaving orbit, the spacecraft descended about 805 m (half a mile) over four hours. At about 125 m (410 feet) above the surface it fired a Checkpoint burn. About ten minutes later a second burn, called Matchpoint, slowed the descent and matched the asteroid's rotation. It then coasted for 11 minutes past a boulder the team nicknamed Mount Doom and reached Nightingale. The sampling arm, called TAGSAM, contacted the surface and released a burst of nitrogen gas, and the spacecraft fired its thrusters and backed away.

The goal was at least 60 g, which NASA compared to a full-size candy bar. After the touch, the team used camera images and an estimate of the sample's mass change to check whether dust and rock had entered the collector head.

The sample comes home

The capsule landed on September 24, 2023. NASA announced the first look on October 11, 2023: high carbon content and an abundance of water-bearing clay minerals. NASA said it would preserve at least 70 percent of the sample at Johnson Space Center for future research.

The mass count rose in steps. On October 20, 2023, curators had 70.3 g (2.48 ounces) from the outside of the sampler head, above the 60 g goal. By February 15, 2024, the bulk total was 121.6 g, roughly double the requirement.

Bennu is not the only asteroid sampled. Japan's Hayabusa and Hayabusa2 missions also brought material home, from Itokawa and Ryugu.

What the sample has shown

Amino acids are the building blocks of proteins. Nucleobases are the parts of genetic molecules that store and pass on instructions. In the January 2025 results, NASA reported that the amino acids in the sample are an equal mixture of left-handed and right-handed forms, while life on Earth almost exclusively uses the left-handed form. The salt minerals form as salty water evaporates over long periods, which points to salty water in Bennu's past. NASA's release notes that some of these building blocks had been found in meteorites before, but this was the first time in a pristine sample collected in space.

The December 2025 results added ribose, a five-carbon sugar, and glucose, a six-carbon sugar. NASA says glucose was found for the first time in an extraterrestrial sample, and that deoxyribose was not detected. Researchers also reported a gum-like substance that is polymer-like and extremely rich in nitrogen and oxygen, and presolar grains, dust from before the Solar System formed, with six times the amount of supernova dust of any other studied astromaterial. Methods that tie a sample's chemistry to the body it came from are described in the article on how scientists know what asteroids are made of.

OSIRIS-APEX and Apophis

After delivering the sample, the spacecraft was renamed OSIRIS-APEX. NASA lists it as an active mission, on a page updated September 23, 2026. It flew past Earth on September 23, 2025, at 1:00 p.m. EDT, passing within 3,438 km (2,136 miles). NASA's mission summary gives June 2029 for the rendezvous with Apophis, after that asteroid's close Earth encounter in April 2029. The plan includes firing the spacecraft's engines near the surface to kick up loose rocks and dust. The story of that encounter is told in the guide to the Apophis flyby.

Common mistakes and myths

Myth: OSIRIS-REx landed on Bennu. NASA says the spacecraft briefly touched the asteroid. It then backed away.

Myth: the sample is only a pinch of dust. The bulk total is 121.6 g (4.29 ounces), about double the 60 g requirement, and NASA calls it the largest asteroid sample ever collected in space.

Myth: the sample shows that life existed on Bennu. NASA states that the findings do not show evidence for life itself. They show that ingredients life uses were present in an asteroid. NASA's sugar release says the same: the sugars are not evidence of life.

Myth: the mission ended in 2023. The spacecraft was renamed OSIRIS-APEX and is on its way to Apophis, and NASA lists it as active.

Frequently asked questions

How much sample did OSIRIS-REx bring back?

NASA reports a bulk sample total of 121.6 g (4.29 ounces) as of February 15, 2024. The mission requirement was at least 60 g.

Where did the capsule land?

It parachuted onto the Department of Defense's Utah Test and Training Range, in Utah's West Desert, on September 24, 2023.

Did the sample contain living things?

No. NASA says the sample shows ingredients that life uses, such as amino acids and sugars, but not evidence of life itself.

What is OSIRIS-APEX?

It is the same spacecraft after the sample delivery, sent to study Apophis after the asteroid's April 2029 close pass of Earth.