American Scientist

THE ASTEROID HUNTER: A Scientist’s Journey to the Dawn of Our Solar System. Dante S. Lauretta. 336 pp. Grand Central, 2024. $30.00.

In the prologue to The Asteroid Hunter, planetary scientist Dante Lauretta warns that asteroid Bennu could strike Earth on September 24, 2182, calling it “the most dangerous rock in our solar system.” It’s an understandable gambit—the risk is real, and asteroid dangers are a proven way of grabbing the public’s attention—but also a misleading one. If you are looking for a doomsday book, this isn’t it. In reality, it’s something much better: a deeply personal tale of space exploration, written by the leader of one of NASA’s most daring robotic missions.

As Lauretta quickly notes, the odds of impact in 2182 are minuscule: about one in 10 million. More to the point, Lauretta is fascinated by life, not death. In his multidecade narrative, he traces Bennu’s progression from an idea, to an anonymous dot of light in a telescope, to the target of a billion-dollar NASA mission. The study of that asteroid, Lauretta explains, will deepen our understanding of the origin of the Solar System and clarify the chemical processes that sparked life on Earth. The least interesting thing about Bennu, it turns out, is that it might kill your great-great-great-great-grandchildren.

The Asteroid Hunter’s proper narrative begins with Lauretta’s own origin story. He writes about his years as a fatherless teenager doing his best to help raise his much younger brothers, and also about his time as a student, drifting through five years of undergraduate life, motivated by articles in Omni magazine as much as by anything in his academic courses. Driven by curiosity about the possibility of alien life, Lauretta ventured into graduate research in the early 1990s: first in SETI (the search for extraterrestrial intelligence), followed by Mars research, then the study of meteorites and cosmic chemistry at Arizona State University and at the University of Arizona. But it was far from clear, even to him, where these pursuits would eventually lead.

The big turning point came when Michael Drake, director of the University of Arizona’s Lunar and Planetary Laboratory, decided to propose a NASA mission to visit an asteroid, collect samples of its surface, and bring them to Earth for detailed study. The timing seemed right: NASA had recently launched Genesis, a space probe to bring back samples of atoms from the Sun, and the Japan Aerospace Exploration Agency (JAXA) had just begun its own attempt to sample an asteroid. Even so, what Drake had in mind was a novel and complex mission, one with a high risk of failure.

In February 2004, Lauretta, Drake, and engineer Steve Price from Lockheed Martin huddled together to sketch out a workable plan of assault on an asteroid that they could pitch to NASA. The concept came together, literally, as a sketch on a cocktail napkin: The three men gathered at the Audubon Bar, a hotel watering hole not far from the University of Arizona campus, and drew up plans for a mission concept that Lauretta dubbed OSIRIS—a mashup of the words Origins, Spectral Interpretation, Resource Identification, and Security. (The scene takes on darker overtones when Lauretta later reveals that Drake was not merely a social drinker, but an alcoholic whose addiction had devastating consequences.)

With the birth of the OSIRIS concept, Lauretta’s life changed, as does the tone of The Asteroid Hunter. The book expands from an intimate autobiography into a broader managerial case study of the collective effort required to bring a grand, difficult concept to reality. To make OSIRIS happen, Lauretta and Drake had to build a team and balance different personalities and types of expertise. But before any of that, they had to clear the sky-high standards of NASA’s reviewers.

The first OSIRIS proposal to NASA got shot down immediately, in part because Lauretta and Drake hadn’t yet identified a plausible asteroid to visit. They revamped their proposal, selected Bennu (then known as 1999 RQ 36) as their target, and reapplied. They got shot down again, this time for needing too much money to do the job. Instead of downsizing, they gambled on going bigger, expanding the scope of their proposal and aiming for a higher category of NASA funding. In keeping with the increased ambition, they renamed their mission OSIRIS-REx (the REx stands for “Regolith Explorer,” referencing a technical term for the loose surface material on an asteroid). OSIRIS-REx ticked all the boxes and received full approval in 2011.

The first OSIRIS proposal to NASA got shot down immediately, in part because Lauretta and Drake hadn’t identified a plausible asteroid to visit.

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Five years of grueling design and development work followed, which Lauretta chronicles in loving and agonizing detail. OSIRIS-REx needed an autonomous guidance system that could allow it to touch down safely on an asteroid whose surface structure and texture were completely unknown. It needed a way to collect samples in an airless environment where the gravity is just 1/100,000th of what it is on Earth. And it had to be able to deliver its precious cargo safely to Earth, 100 million miles away. Drake died just five months after mission approval, adding yet another challenge. Lauretta became the principal investigator for OSIRIS-REx, abruptly inheriting ultimate responsibility for making sure all the different parts functioned properly.

Finally, at sunset on September 8, 2016, the product of all that labor rocketed off from Cape Canaveral in Florida. Here, Lauretta drops the businesslike tone that dominates the managerial section of the book and toggles back to his youthful, more poetic self. “I felt my body rising alongside OSIRIS-REx, soaring into space together on our cosmic expedition,” he writes.

And so begins the third act of The Asteroid Hunter, as Lauretta’s story moves beyond dreaming and building to exploring. Asteroid Bennu is just 500 meters (1,600 feet) wide, far too small to show any visible detail from Earth. When OSIRIS-REx approached its target in October 2018, it was the first time anyone had set eyes on this tiny world. Bennu turned out to be a diamond-shaped collection of rubble, one that Lauretta portrays as full of marvelous but treacherous surprises. For reasons unknown, Bennu sometimes spits out flying rocks. (Possibly the mini-eruptions are triggered by unseen meteoroid impacts.) The mission team expected to find a fine, dusty landscape; instead, they encountered an array of menacing boulders.

Then when OSIRIS-REx touched down to collect pieces of the asteroid, the solid-looking surface turned out to be more like celestial quicksand. “If OSIRIS-REx hadn’t immediately fired its thrusters to back away after collecting its sample, it would have sunk into Bennu,” Lauretta writes, his anxiety still raw. But the thrusters did fire, the experimental sample collector functioned perfectly, and the spacecraft’s sample container returned to Earth as planned. It landed in Utah on September 24, 2023, at 10:52 a.m. EDT. The only mishap: a parachute glitch that caused the sample to touch down one minute early.

The fourth act of Lauretta’s story runs beyond the pages of The Asteroid Hunter, because it is still being written. Scientists are just starting to extract the riches that OSIRIS-REx brought home. Bennu is a primeval, carbon-rich asteroid, made of material that has never been analyzed in detail before. Studying its composition will help explain how stardust gathered into pebbles, boulders, and planets in the early Solar System. After Earth formed, asteroids like Bennu continued to bombard it, seeding our planet with organic compounds. Soon we will know a lot more about those compounds, too, and their possible role in getting life started.

And yes, OSIRIS-Rex may help keep us safe from future bombardments. The same techniques used to land the spacecraft on Bennu could someday be used to deflect a hazardous asteroid if we find one that is truly on an Earth-threatening course. That aspect of OSIRIS-REx’s mission is ongoing. After dropping off its sample capsule, the spacecraft was renamed OSIRIS-APEX and redirected toward another near-Earth asteroid, Apophis, that will pass just 20,000 miles from Earth in 2029.

Lauretta will not be along for that ride, however. His protégé Dani DellaGiustina will take over as principal investigator, as Lauretta moves on to new ventures. Space exploration requires extreme patience, and with it a willingness to hand over the job from generation to generation. Lauretta embraces that hard truth with neither self-pity nor sentimentality. Instead, he focuses on the scientific aspirations that transcend time, which he articulates in nerdy grandeur as he ponders the successful delivery of OSIRIS-REx’s precious cargo.

“An overwhelming sense of calm came over me,” Lauretta writes. “I felt in my soul that the final phase of our mission, sample analysis, would reveal the deepest secrets of the cosmos.”