In September 2023, a small capsule parachuted into the Utah desert carrying dark dust and pebbles from an asteroid that the spacecraft had visited years earlier. The capsule belonged to NASA's OSIRIS-REx mission, and its cargo from asteroid Bennu has become one of the most closely studied samples of space material ever collected. This article explains how the mission worked, what scientists have found so far, and how it connects to Apophis.
Bennu is a near-Earth asteroid about 500 meters across, according to NASA. It is rich in carbon and is thought to be a fragment of a larger parent body that broke apart long ago. Scientists wanted it for two reasons. First, carbon-rich asteroids preserve material from the early Solar System, so they work like time capsules. Second, Bennu's orbit brings it close to Earth, which makes it both reachable and worth understanding. For background on how objects like this are grouped, see What Is a Near-Earth Object?
The touchdown gave a surprise. The surface was far looser than expected, and the sampling arm sank into it. So much material entered the collector that some rocks held the lid open and particles drifted out until the team stowed the sample early.
The mission's requirement was at least 60 grams. After the curation team at NASA's Johnson Space Center finished opening the container, the final tally announced in early 2024 was about 121.6 grams (roughly 4.3 ounces), around double the goal. That is a small amount by everyday standards, but it is plenty for science. Each lab receives tiny portions, and a significant share is kept untouched for future researchers who will have better instruments than we have today.
Studies published in 2025 gave the first detailed picture. Researchers reported that the material is rich in volatile compounds, including ammonia and a wide range of nitrogen-bearing organic molecules. According to NASA, scientists identified 14 of the 20 amino acids that life on Earth uses to build proteins, along with all five nucleobases used in DNA and RNA.
It is important to read this correctly. These are ingredients, not life. Similar compounds have been found in some meteorites and in samples from the Japanese mission to asteroid Ryugu. What is new is that the Bennu sample was collected in space and kept sealed from Earth's environment, which reduces the worry about contamination. Researchers also noted that the amino acids came in a roughly equal mix of left- and right-handed forms, unlike the strong left-handed preference in life on Earth.
A companion study found salts and minerals, including sodium-rich carbonates, sulfates, chlorides and phosphates, that appear to have formed when salty water evaporated on Bennu's parent body billions of years ago. This suggests the parent body once held liquid water, which helps explain how organic chemistry could develop inside such asteroids.
Tracking the spacecraft near Bennu let scientists measure how sunlight gently pushes the asteroid through the Yarkovsky effect. That improved its orbit prediction. Researchers using the mission data reported a cumulative impact chance of about 1 in 1,750 for the period from 2135 to 2300, and the most notable single date is September 24, 2182, at about 1 in 2,700. In other words, there is better than a 99.9 percent chance that Bennu will miss Earth. To see how such odds are calculated and rated, read How NASA Tracks Asteroids.
The detailed knowledge of Bennu's rubble-pile structure also matters for defense planning. A loose pile of rocks may react differently to a deflection attempt than a solid boulder, a theme explored in the DART mission explained and the wider story of planetary defense.
The spacecraft did not retire after dropping off the capsule. NASA renamed the extended mission OSIRIS-APEX, short for OSIRIS-Apophis Explorer, and redirected it to Apophis. The plan is for the spacecraft to arrive after the April 13, 2029 flyby and study the asteroid for about 18 months, observing how Earth's gravity changed it. Mission plans can shift, so check NASA for updates. Learn more about the flyby in Apophis 2029: Everything You Need to Know, and see why it poses no threat in Is Apophis Dangerous?
Facts in this article are drawn from public scientific sources. For primary information, see: