Tuesday, November 10, 2009 at 9:55:41 AM - by Danny Vo

Boosted by an anonymous $1 million gift, the Planetary Society will soon test a small spacecraft propelled by solar energy.

The craft, LightSail-1, consists of three modules that are "bigger than a toaster and smaller than a breadbox," in the words of the society's executive director Louis D. Friedman. The Mylar sails to which the modules are attached will unfurl to a 340-square-foot area.

LightSail-1 will orbit at an altitude of 500 miles, the Planetary Society says. The next LightSail craft will be tested at higher altitudes; the third one will be sent even deeper into space.

Solar propulsion may be the key to sending spacecraft outside the solar system without rockets or other legacy propulsion methods. Photons - light particles - will hit crafts' sails and push them along, slowly at first but then extremely fast. Friedman suggested that speeds of 100,000 miles per hour are reachable.

LightSail-1 is not the first Planetary Society solar sail project. In 2005, the group launched a prototype attached to a Russian rocket - but the rocket failed and crashed into the Barents Sea. Undeterred, society members are once again testing solar energy in space travel.