A brown-and-white capsule that spent the past seven years swooping through the solar system — and sojourning at an asteroid — has finally come home. And it has brought a cosmic souvenir: a cache of space rock that scientists are hungry to get their hands on.
On Sunday morning, those scientists waited eagerly as the pod shot through Earth’s atmosphere at thousands of miles per hour. It gently parachuted down into the muddy landscape of the Utah Test and Training Range, about 80 miles west of Salt Lake City, at 8:52 a.m. local time.
“This mission proves that NASA does big things,” said Bill Nelson, the administrator of the space agency. “Things that inspire us, things that unite us, things that show really nothing is beyond our reach.”
The capsule’s landing is a major win for a NASA mission called OSIRIS-REX, which stands for Origins, Spectral Interpretation, Resources Identification and Security-Regolith Explorer. The spacecraft set out in 2016 to retrieve material from Bennu, a carbon-rich asteroid about 190 feet wider than the height of the Empire State Building. Researchers hope this pristine space dirt will reveal clues about the birth of our solar system and the genesis of life on Earth.
“This is a gift to the world,” said Dante Lauretta, a planetary scientist at the University of Arizona and the principal investigator of the OSIRIS-REX mission, at a news conference last month.
Scientists who were working on the mission endured many twists and turns, including a seven-year struggle to get the project greenlit by NASA. Their perseverance paid off as OSIRIS-REX became the first American spacecraft to retrieve material from an asteroid, bringing back a staggering amount of matter from space for scientists around the world to study. But the victorious final act means so much more for the OSIRIS-REX team members, many of whom “grew up on this mission,” Lauretta said.
“A little bit of us is on that spacecraft,” said Rich Burns, the OSIRIS-REX program manager at NASA Goddard Space Flight Center, at the news conference. “And a little bit of us is coming home with it.”
Bennu, a near-Earth asteroid, is currently many millions of miles from our planet. Like other asteroids in the solar system, it is a geological relic of the protoplanetary disk — a swirling mix of gas and dust that eventually coalesced into planets — that surrounded our sun billions of years ago. One theory is that small worlds like Bennu once seeded Earth with the prebiotic ingredients needed to form life.
But it is difficult to test this idea using meteorites, pieces of asteroids that reach Earth’s surface, which are heated by the atmosphere and are then contaminated by microbes on the ground, Lauretta said. Instead, many scientists turn their eyes (and their instruments) to space.
This is not the first chunk of an asteroid brought back to Earth. In 2010, the Hayabusa mission, led by Japanese space agency JAXA, managed, despite technical troubles, to recover less than a milligram of material from a near-Earth asteroid named Itokawa. A decade later, a follow-up mission, Hayabusa2, retrieved a few grams of space rock from Ryugu. With that sample, scientists have found evidence suggesting that asteroids had delivered water to the early Earth and discovered the presence of uracil — a building block of RNA, a molecule that helps form proteins.
OSIRIS-REX’s delivery will provide an abundant new stock of space rock. The team anticipates about half a pound of unsullied asteroid dirt. Shogo Tachibana, a planetary scientist at the University of Tokyo who led the Hayabusa2 sample analysis and is now a co-investigator on OSIRIS-REX, has “no idea” whether Bennu will be anything like Ryugu — but it’s what he is most looking forward to finding out.
From the beginning, the mission was a marathon. American scientists had long dreamed of fetching dust from an asteroid, and in 2004, a group submitted an application for what would become OSIRIS-REX. But NASA returned the project with the lowest ranking: Category 4, or “thanks, but no thanks,” Lauretta said. “The first proposal just bombed.”
The team tried again in 2007. This time, it scored a ranking of Category 1 — but failed to snag funding because the budget was too large.
The third time was the charm. NASA selected the project in 2011. “So that began our real journey,” said Harold Connolly, a cosmochemist at Rowan University who joined OSIRIS-REX 15 years ago. The team spent another half-decade “making sure all our little ducks were in a row,” he said, including designing and building the spacecraft, mapping the trek to Bennu and plotting the science campaign.
OSIRIS-REX launched in 2016, embarking on a roundabout series of fuel-efficient loops before arriving at Bennu on Dec. 3, 2018.
Mission specialists expected Bennu’s surface to consist of smooth, sandy seas of fine particles. But as the asteroid came into focus, they found it was rocky and rough, with boulders, some 10 stories tall, sprinkled throughout. That made finding a place where the spacecraft could safely retrieve a sample from the surface riskier.
Engineers were troubleshooting that problem when Bennu threw them another loop: It was spewing rubble into space. That was “really exciting scientifically,” said Sandy Freund, the OSIRIS-REX program manager at the aerospace company Lockheed Martin. But “from an engineering standpoint,” the discovery posed a new problem.
The mission scientists frantically churned out calculations to make sure OSIRIS-REX was safe from being struck by the asteroid’s gravelly plumes. The operations team swiftly wrote new navigation software that could compensate for the rugged terrain on Bennu.
After two years of surveying the asteroid, the mission team chose a spot it named Nightingale, near the asteroid’s north pole. In October 2020, OSIRIS-REX punched the surface of Bennu using a tool that was supposed to bounce off Bennu like a pogo stick.
But it did not exactly bounce as planned. Connolly recalled that he was shocked at how deep the instrument penetrated into the asteroid — about 1 1/2 feet.
“We thought it would be a little more firm,” he said. “But it turns out gravity is basically the only thing that’s holding it together.”
The blow excavated a 30-foot-wide crater and blasted dusty debris into space — an unintentional experiment that revealed some properties of Bennu’s subsurface.
Six months later, OSIRIS-REX captured one last look at Nightingale and then began the two-year journey back to Earth. “It was definitely an adventure,” Lauretta said.
At 2 a.m. local time on Sunday morning, the OSIRIS-REX command team in Littleton, Colo., evaluated the landing conditions and held a go-or-no-go poll on the capsule drop. The team voted go and OSIRIS-REX released the capsule at 4:42 a.m.
Four hours later, it entered Earth’s atmosphere. A high-altitude camera on a NASA plane captured the fireball streaking across the lavender sky as the capsule’s heat shield protected the cargo from temperatures of more than 5,000 degrees Fahrenheit.
The first parachute inflated 19 miles above the surface. The main chute deployed at a higher altitude than planned, which led to a landing three minutes earlier than expected.
The capsule, charred from its journey through the atmosphere, landed on its nose. About half an hour after the landing, a mission team reached the capsule and began the procedures to recover it.
This article originally appeared in The New York Times.