101955 Bennu
Bennu – discovered in 1999 – is a small, near-Earth asteroid that passes close to Earth about every six years.
On Oct. 20, 2020, NASA’s OSIRIS-REx spacecraft successfully descended to the surface of asteroid Bennu and collected rocky material from sample site Nightingale during its Touch-and-Go (TAG) sample collection maneuver. Two days later, the mission team received images from OSIRIS-REx confirming the spacecraft had collected more than enough material to meet one of its main mission requirements – acquiring at least 2 ounces (60 grams) of the asteroid’s surface material.
The team later successfully stored the sample in the Sample Return Capsule (SRC) for the spacecraft’s journey back to Earth.
On May 10, 2021, OSIRIS-REx said farewell to Bennu, and headed to Earth where it delivered the asteroid sample on Sept. 24, 2023.
After dropping off the sample, the spacecraft began a new mission as OSIRIS-APophis EXplorer (OSIRIS-APEX) and headed toward an encounter with asteroid Apophis in 2029.
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An ancient relic of our solar system’s early days, Bennu has seen more than 4.5 billion years of history. Scientists think that within 10 million years of our solar system’s formation, Bennu’s present-day composition was already established.
Bennu likely broke off from a much larger carbon-rich asteroid about 700 million to 2 billion years ago. It likely formed in the Main Asteroid Belt between Mars and Jupiter, and has drifted much closer to Earth since then. Because its materials are so old, Bennu may contain organic molecules similar to those that could have been involved with the start of life on Earth.
10 Need-to-Know Things About Bennu
1
Found in 1999
The asteroid was discovered by the Lincoln Near-Earth Asteroid Research (LINEAR) survey on September 11, 1999.
2
Named by 9-year-old
Bennu’s original designation was 1999 RQ36. In 2013, a third-grade student named Michael Puzio won a contest to name the asteroid.
3
Far from home
Bennu has drifted into near-Earth space because of gravitational interactions with giant planets and the gentle push of heating from the Sun.
4
Low density
Bennu's density is only about 30 percent more than water. This suggests the asteroid is probably a loose collection of rocks, like a pile of rubble.
5
Wave every 6 years
Bennu has a close approach to Earth every six years.
6
Potentially hazardous
Scientists estimate Bennu has a 1‐in‐2,700 chance of impacting the Earth during one of its close approaches to the Earth in the late 22nd century.
7
burn up or bolt?
Bennu may burn up in the Sun. Over millions of years, of all of the planets, Bennu is most likely to hit Venus
8
Big Boulder
The boulder that juts from Bennu's south pole is about 164 feet (50 meters) high and 180 feet (55 meters) wide.
9
Moonless
Although some asteroids have moons, Bennu does not.
10
Collecting a Sample
NASA’s OSIRIS-REx mission studied Bennu in unprecedented detail. It collected a sample in 2020, and delivered it to Earth on Sept. 24, 2023.
FAQ: Why Bennu?
Bennu is relatively close to Earth, it's really old and well-preserved. It might even help us in our search for clues to the origins of life – and learn how to preserve life by keeping near-Earth asteroids at bay. Read all 10 reasons scientists chose to go to Bennu ›
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