Investigators at NASA have linked the crash of the Genesis spacecraft on September 8 to a simple design error that went undetected despite many layers of review. Either of two redundant pairs of switches could have triggered the release of a parachute when the craft hit the upper atmosphere. But because all four switches were installed backward, as specified by the Lockheed Martin design, the chute never deployed and the probe smashed into the Utah desert at more than 300 kilometers an hour. The collision destroyed the spacecraft, but scientists may eventually extract much of the data they had anticipated from the quarter-billion-dollar mission.

For nearly two and a half years, the Genesis spacecraft collected the charged particles that comprise the solar wind from a vantage point beyond the reach of the magnetic field of Earth. Some 1020 particles, about half a milligram total, slammed into silicon wafers, gold foil and other ultrapure materials, into which they buried themselves some 100 nanometers deep. The spacecraft then returned with the samples to Earth. By analyzing the composition and isotopic abundance of the minute quantities of embedded material, scientists hoped to learn more about the sun and the origins of the solar system.

The Genesis team devised a midair recovery of the craft to minimize contamination and the shock of impact. The switches in question were intended to detect the deceleration of the craft as it hit Earth's atmosphere so that parachutes could slow it enough to be nabbed by a helicopter. But they failed to do so, as a result of Lockheed's flawed design. Michael Ryschkewitsch of NASA, who heads the Genesis Mishap Investigation Board, stressed that the backward switches were only the proximate cause of the crash. One of the questions we have to answer, he notes, is: How did we not catch this?

Although the craft perished, the particles are still buried in the collectors, many of which survived unbroken, albeit soiled. Several thousand containers with samples have been shipped to the Johnson Space Center in Houston. Eileen Stansbery, head of the contamination team, says that the challenge is to devise cleaning techniques that don't spoil the sensitive measurements. It's going to take us a lot longer and be more difficult to retrieve the science because of the crash, she admits. Nevertheless, Stansbery adds, long term, I have a lot of confidence that we're going to meet our objectives. It always was going to take years.