SMART NEWS

How to See NASA’s Bennu Asteroid Sample in Person

A tiny piece of the space rock made its public debut at the Smithsonian National Museum of Natural History, as scientists study the rest of the sample

Will Sullivan

Daily Correspondent

A tiny black rock from an asteroid sits in a metal container
The asteroid sample that is now on display at the National Museum of Natural History. By studying the retrieved space rocks, scientists aim to better understand how water and organic material first arrived on Earth. NASA Johnson Space Center

In late September, NASA’s OSIRIS-REx mission delivered bits of rock and dust collected from a distant asteroid to Earth—the first sample of its kind brought to the United States. Now, the general public can catch a glimpse of one of the asteroid’s rocky fragments, which went on display at the Smithsonian’s National Museum of Natural History on Friday.

“The OSIRIS-REx mission is an incredible scientific achievement that promises to shed light on what makes our planet unique,” Kirk Johnson, the museum’s director, says in a statement.

The asteroid, called Bennu, is shaped like a spinning top and spans about one-third of a mile wide at its equator. Scientists think the 4.5-billion-year-old object, which orbits the sun between Earth and Mars, is composed of some of the solar system’s oldest materials, forged in dying stars before the planets formed.

Examining this ancient matter could hold clues about how organic materials first arrived on Earth, so NASA launched the OSIRIS-REx mission in 2016 to retrieve a sample from Bennu’s surface. The spacecraft arrived at the asteroid in 2018, surveyed the rock for an ideal collection site and ultimately took its sample in 2020.

The spacecraft traveled billions of miles to and from Bennu, then dropped the sample to Earth from 63,000 miles away, before continuing on its next mission to study the asteroid Apophis. Last month, an initial examination of the sample revealed evidence of a high carbon content and water on Bennu.

When the team was unpacking their sample, they found that “bonus” material from the asteroid, beyond the larger fragments in the main sample container, covered the collector head, canister lid and base. Containing this extra matter delayed NASA’s processing of the sample.

“The very best ‘problem’ to have is that there is so much material, it’s taking longer than we expected to collect it,” deputy OSIRIS-REx curation lead Christopher Snead, of NASA’s Johnson Space Center, said in a statement in September.

The small sample at the museum—the first available to the public—is about 0.3 inches in diameter and weighs just 0.005 ounces. It is held in a stainless steel bottle with a glass viewing port and kept in a pure-nitrogen environment to prevent contamination, writes Space.com’s Robert Z. Pearlman. The rock sits alongside scale models of OSIRIS-REx and the Atlas V rocket that carried the probe to space.

“The knowledge we gain from the study of the asteroid Bennu sample will influence our scientific understanding of the solar system for generations to come,” NASA administrator Bill Nelson says in the museum’s statement. “And in sharing this 4.5-billion-year-old sample with the public, we hope to inspire the Artemis generation and future generations to ask even bigger questions and make greater scientific discoveries.”

One asteroid sample is on display in the museum’s Janet Annenberg Hooker Hall of Geology, Gems and Minerals meteorite gallery. But the Smithsonian Institution also received an additional sample to study behind the scenes, per Space.com.

“The Bennu sample will take its place beside meteorites that come from the dawn of the solar system, the metallic cores of ancient asteroids and even those knocked off Mars that fell to Earth, as well as moon rocks returned by the Apollo astronauts,” Tim McCoy, the museum’s curator of meteorites and an OSIRIS-REx mission member, told Space.com’s Monisha Ravisetti before Friday’s unveiling. “We placed it at the front of the Moon, Meteorites and Solar System gallery, because it represents the very beginning of our solar system’s story.”

Next, two more samples from Bennu will go on display, one at the Alfie Norville Gem & Mineral Museum at the University of Arizona and the other at Space Center Houston.

Scientists will continue analyzing the samples for the next two years and will save at least 70 percent of the Bennu rocks for further research, per NASA.

Get the latest stories in your inbox every weekday.

Will Sullivan

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