© A. Ikeshita/MEF/ISAS
Artist's conception of the Hayabusa spacecraft
A 1,124-pound (510-kilogram) space probe will "collide" with our home planet in June 2010 to simulate an approaching asteroid, Japanese scientists have announced.

The Hayabusa spacecraft is currently on its way back to Earth after a successful mission that landed on and hopefully collected samples from the asteroid Itokawa.

Potential samples will be aboard a heat-resistant capsule that will separate from Hayabusa shortly before re-entry into Earth's atmosphere so they can be recovered. But experts say the main body of the craft will most likely disintegrate during the trip through Earth's atmosphere.

Although the plan was not part of Hayabusa's original mission, scientists at the Japan Aerospace Exploration Agency (JAXA) recently decided to make the most of the doomed probe's return.

"Even though Hayabusa is not actually an asteroid, it will be on a path that will cause it to collide with the Earth in the same way as an asteroid," said JAXA spokesperson Akinori Hashimoto. "We will monitor its movements, and the data will enable us to accurately predict the future paths of asteroids that are on course to come close to the Earth."

A Better Lookout

While other space agencies have programs for tracking asteroids that might hit Earth, JAXA doesn't yet have the ability to monitor these so-called near-Earth asteroids. So a team of researchers headed by Makoto Yoshikawa has developed a prototype system to calculate the trajectory, time, speed, and likelihood of an asteroid impact.

In October 2008, the team had a chance to test its system by tracking asteroid 2008 TC3, an incoming space rock about 13 feet (4 meters) wide that astronomers at the Catalina Sky Survey in Arizona had spotted a few hours before it became a fireball in the skies over Sudan.