#24: Space Ship Sails on a Breeze of Sunlight

By Andrew Moseman|Thursday, December 16, 2010

Named for the mythical youth who died after flying too close to the sun, the Japanese spacecraft Ikaros is poised to breathe new life into space exploration. Ikaros is the first successful solar sail, using the physical pressure of sunlight to propel a huge, thin film the way that wind pushes a conventional sail at sea.

The craft was launched in May and spread itself fully open the following month. “The solar sail was shining in the dark of space,” says project leader Osamu Mori of JAXA, Japan’s space agency. “It was very beautiful.”

Solar sailing is a decades-old idea that, until now, nobody had been able to harness. Japan’s success is reinvigorating the field. The Planetary Society, which lost a sail in a 2005 launch accident, is building a new one scheduled for launch in 2011. Scientists at NASA and the European Space Agency are revisiting their designs as well.

The idea is enticing because solar sails can navigate through space without any fuel, making them ideal for lengthy round-trip missions, says Bill Nye, director 
of the Planetary Society. Someday a huge space-based laser could even push a sail to another star system. “You could drive all over the universe with the momentum of photons,” Nye says.

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