A Long Hike Home for Hayabusa

Continuing mechanical and communications problems mean a Japanese space craft that recently visited an asteroid won't make it back to Earth until 2010, 3 years later than originally planned, scientists from the Institute of Space and Astronautical Science, a part of the Japan Aerospace Exploration Agency (JAXA), announced today. Even worse, the Hayabusa space craft may not be carrying any of the asteroid samples astronomers were hoping would shed light on conditions in the early universe.

The Hayabusa team had previously announced it was confident the tiny spacecraft had picked up rock samples while briefly sitting on the surface of asteroid Itokawa (Science, 2 December, p. 1409). After a closer look at data radioed home by Hayabusa, however, the JAXA scientists could not confirm whether the spacecraft had fired a projectile into the surface of the asteroid. That bullet was supposed to blast rock fragments into a collection horn. The team is hoping that as Hayabusa touched down, it stirred up sand and dust and that some of this material found its way into the collector.

In the latest development, ground crews have been unable to regain control of Hayabusa because of communications problems and, perhaps, troubles with the spacecraft's thrusters. The team has now missed the window of opportunity to set Hayabusa on course for its 300 million kilometer journey back home--a rendezvous originally planned for 2007. The next best opportunity for the spacecraft to drop its capsule to Earth will be in 2010.

Despite the setback, project manager Jun'ichiro Kawaguchi vowed to try everything possible to retrieve the capsule. Given the high expectations of the worldwide scientific community and the Japanese public, "we have an obligation to try" to bring it back to Earth, he says. Kawaguchi also staunchly defends the team's technological accomplishments, which include a novel ion engine for long-range space travel, autonomous navigation technologies, and remote sample retrieval techniques. These advances are already being incorporated into space exploration plans by other countries, he says.

Although a sample from Itokawa would be the biggest prize, Hayabusa's bevy of x-ray, gravity, and image sensors have already transmitted enough data back to Earth to fuel scientific debates for years to come, researchers say. Derek Sears, a planetary scientist at the University of Arkansas, Fayetteville, says he and colleagues have been pouring over the images of Itokawa snapped by Hayabusa: "We're all looking at the same images, and every one of us is saying something different about what those images mean."

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