THE ASTEROID HUNTER

An uplifting story of a NASA project to send an unmanned probe to an asteroid with the aim of collecting a soil sample.

Lauretta, the mission’s principal investigator, shows that this particular asteroid, named Bennu, had important advantages: It was relatively close to Earth, its composition indicated that it could provide clues to the origin of the solar system, and it was as large as an aircraft carrier. Another issue, however, was that astrophysical calculations suggested that at some point in the future—specifically, September 2182—Bennu might “hit the surface of the Earth at a velocity of Mach 36, or 27,000 miles per hour—a freight train crashing into the planet.” The chance was only about one in 1,750, but NASA thought that Bennu was worth further investigation. The author tracks the years of planning, testing, and simulations. Building a spacecraft for the two-year journey to Bennu was difficult, but designing for the landing was even harder. Lauretta explains how NASA scientists solved countless problems during the design phase, and the OSIRIS-REx mission took flight in September 2016. when the spacecraft reached the asteroid, however, scientists discovered that Bennu held a few surprises. Far from being a smooth rock, Bennu offered very few possible landing sites, and the pitted surface turned out to be extremely soft. Nevertheless, touchdown was achieved, and a sample was collected. Then it was time for the return journey, and the probe landed in Utah in September 2023. The sample is now being analyzed in every possible way, but Lauretta is certain that the mission itself was entirely successful. The message is that the U.S. government can still complete remarkable projects, a resonant, hopeful conclusion that is much needed in these chaotic times.

Lauretta’s account of a historic mission is an impressive combination of fascinating science and human inspiration.