SMART NEWS

A Sample of Ancient Asteroid Dust Has Landed Safely on Earth

NASA’s OSIRIS-REx mission retrieved bits of rock and dust from the asteroid Bennu, which could help scientists uncover the origins of life on our planet

Will Sullivan

Daily Correspondent

A black, saucer-like capsule sits on the desert surface
The capsule holding the asteroid sample shortly after touching down in the desert on September 24 at the Department of Defense's Utah Test and Training Range. NASA / Keegan Barber

A capsule carrying bits of rock and dust from a distant asteroid touched down in Utah on Sunday morning. The asteroid samples—the first carried by a spacecraft to the United States—could help scientists better understand how planets formed in our solar system and trace the origin of organic molecules that led to the first life on Earth, according to a statement from NASA.

The ancient asteroid, named Bennu, has likely retained its current composition since within ten million years of the solar system’s formation, which occurred around 4.6 billion years ago. The samples of its dusty ground are older than Earth, and they could contain hints as to whether asteroids carried organic compounds to our home planet.

“We hope the Bennu samples will help us address the question, ‘Which building blocks were delivered by meteorites?’” Philipp Heck, the curator of meteorite and physical geology collections at the Field Museum, tells Vox’s Ellen Ioanes.

“I find it fascinating that we can learn about our origins and about the deep history of the solar system by studying these very boring-looking rocks,” Sara Russell, a geophysicist at the Natural History Museum in the United Kingdom, tells National Geographic’s Carrie Arnold. “It’s almost like meeting a baby. I can’t wait to see what it looks like.”

The sample return was more than seven years in the making. On September 8, 2016, NASA’s OSIRIS-REx probe launched to space and began its journey toward Bennu.

Of the 780,000 known asteroids in the solar system at the time, Bennu was an appealing destination. For one, it was an ideal size—smaller asteroids spin too fast to land on easily, and they hurl materials a spacecraft could potentially gather into space. But with a longer diameter about the height of the Empire State Building, Bennu seemed to be an easier target. Scientists were intrigued by the asteroid’s old age and the fact that it contains carbon—and possibly carbon-based organic molecules.

While many asteroids reside in a belt between Mars and Jupiter, Bennu orbits the sun closer to Earth. Still, NASA’s spacecraft had to travel 1.2 billion miles over the span of two years to reach the asteroid. In December 2018, OSIRIS-REx began orbiting Bennu.

The first images of the asteroid revealed to scientists that instead of having a smooth and sandy surface, Bennu was covered in boulders—and was flinging rocks into space. This would make approaching the asteroid more challenging. The spacecraft spent months mapping the rocky surface, and NASA’s mission team searched for the best place to sample from, eventually settling on a site dubbed “Nightingale” in December 2019.

In October of the next year, the spacecraft approached Bennu’s surface and made contact. It shot nitrogen gas at the asteroid to kick up dust and rocks, which the probe collected. Then, it quickly fired its thrusters to withdraw from the surface, and in May 2021, OSIRIS-REx began its two-year journey back to Earth.

At long last, the spacecraft released the capsule containing its sample from about 63,000 miles above Earth’s surface on Sunday morning. Over the next four hours, the capsule fell back to Earth—first moving slowly through space, then racing through Earth’s atmosphere at 36 times the speed of sound. It landed safely in the Department of Defense’s Utah Test and Training Range.

“It looked perfect. There was no sign of any damage,” Dante Lauretta, a planetary scientist at the University of Arizona and the leader of NASA’s OSIRIS-REx mission, says to NPR’s Nell Greenfieldboyce. “It was like seeing an old friend that you hadn’t seen for a long time.”

Carrying an estimated 8.8 ounces of space goodies, the capsule was brought by helicopter to a nearby, temporary clean room, where it received a flow of nitrogen to keep the sample from getting contaminated by Earthly materials in its new surroundings.

The canister containing the sample was slated to be transported to NASA’s Johnson Space Center on Monday, September 25, where the cataloging and analysis of its contents will soon begin.

Meanwhile, OSIRIS-REx’s journey continues. After releasing the capsule, the spacecraft is moving on to its next destination, the asteroid Apophis.

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Will Sullivan

Will Sullivan is a science writer based in Washington, D.C. His work has appeared in Inside Science and NOVA Next.