New solar-sail mission planned after 2005 failure

By Steve Gorman

LOS ANGELES (Reuters) - Backers of a failed mission to launch the world's first solar-sail spacecraft unveiled plans on Monday to try again five years later with a smaller, swifter satellite to test the limits of sunlight propulsion.

The privately funded venture, organized by the Pasadena, California-based Planetary Society, is based on the premise of spaceflight powered not by rocket fuel or chemical propellants but by streams of photons -- light particles -- pushing against a sail in the vacuum of space.

Some space enthusiasts see solar sailing as a first step in light-powered propulsion technology that may prove the most feasible mode of travel to distant stars.

But experts say the technology has nearer-term applications in establishing permanent solar weather stations for monitoring magnetic storms on the sun that can wreak havoc on Earth-bound communication networks and electrical grids.

The project grew out of an idea imagined by the society's co-founders -- executive director Louis Friedman and late astronomer and author Carl Sagan -- to send a solar sail craft to rendezvous with Halley's Comet in the 1970s.

The first attempt to launch such a space vehicle, dubbed Cosmos 1, ended in disaster when a Russian rocket that was supposed to carry it into orbit malfunctioned shortly after liftoff from a submarine in the Barents Sea in June 2005.

Organizers have since redesigned the spacecraft. The new LightSail vehicle, the size of a loaf of bread, is smaller and 20 times more lightweight than Cosmos but built to accelerate more quickly once its aluminum Mylar sail is unfurled in high orbit, 500 miles or more above Earth.

That's about twice as high as the usual orbit of NASA's space shuttle, said the Planetary Society's Bruce Betts.