David W. Brown writes:

On a brisk day in February, 2004, Dante Lauretta, an assistant professor of planetary science at the University of Arizona, got a call from Michael Drake, the head of the school’s Lunar and Planetary Laboratory. “I have Lockheed Martin in my office,” Drake said. “They want to fly a spacecraft to an asteroid and bring back a sample. Are you in?”

The two men met that evening with Steve Price, then a director of business development for Lockheed Martin Space, on the patio of a hotel bar in Tucson. Over drinks, they scribbled ideas on cocktail napkins. Price explained that the company’s engineers had developed technology that would allow a spacecraft about the size of a mail truck to rendezvous with a near-Earth asteroid, then enter a hummingbird-like mode and “kiss” its surface. The craft’s “beak” would be an unfolding eleven-foot-long mechanism with a cannister on its end, which would kick up material with a little blast of nitrogen. The spacecraft would stow this bounty in a protective capsule, fly back home, and then parachute it to Earth.

Asteroids interest researchers for many reasons. Because most predate the existence of the Earth, they harbor clues about the solar system’s long history. They often contain valuable industrial elements, such as cobalt and platinum, which are getting harder to find terrestrially. In the future, they might provide astronauts with fuel, oxygen, water, and construction material. And they can also pose a threat: in 2004, astronomers discovered that an asteroid named Apophis had an almost three-per-cent chance of striking Earth in 2029, conceivably killing millions. (It’s now projected to miss us by around twenty thousand miles—the equivalent of a round-trip flight from New York to Sydney.)

Although there is no life on asteroids that we know of, biochemists are interested in them, too. At some point in the Earth’s history, chemistry became biology: simpler molecules reacted with prebiotic molecules, and these in turn combined to create DNA, RNA, proteins, and other components of life. The precise conditions that caused this are impossible to determine, because eons of upheaval, including plate tectonics, have left the geologic record of Earth’s distant past incomplete. But asteroids—the building blocks of planets, frozen in time billions of years ago—offer chemical snapshots of what our planet was like before life existed. By crashing to Earth as meteors, they have also added to the planet’s chemical complexity. Many scientists now think that important chemical components of life weren’t cooked up on Earth but delivered, by asteroids, from the larger cauldron of the early solar system. Analyzing a sample retrieved from an asteroid could shed light on where biochemistry came from. [Continue reading…]