I’ve always loved the idea of the solar sail, giant glistening sails that use solar radiation to propel a ship through the solar system (as in the image at left).

But the Finnish Meterological Institute has come up with a better way to utilize that radiation for spacecraft propulsion, “by using long metallic tethers and a solar-powered electron gun to create an ‘electric sail.'” (Via Gizmag.)

Invented in 2006 at the Kumpula Space Centre, the electric solar wind sail, alas, loses some of the romance of the traditional solar sail: it looks more like an antenna (view an animation here):

A full-scale version would consist of up to 100 thin conducting wires as long as 20 km that are kept in a high positive potential by the spacecraft’s on-board solar-powered electron gun. This electric field effectively turns the wires into 50 meter wide sails that can then make use of solar wind. It’s estimated that a 20km long electric sail wire (which weighs only a few hundred grams and fits in a small reel) is equivalent to a one square kilometer solar wind sail when deployed in this way.

Planning for a test mission has begun, and the researchers note that the same technology could also assist in the development of solar power satellites.

In 2004 NASA’s Solar Sail Propulsion Team successfully deployed two 10-meter solar sails made of reflective material 40 to 100 times thinner than a piece of writing paper in a laboratory vacuum environment. But the first solar sail spacecraft, Cosmos 1, failed to enter orbit after its 2005 launch.  (UPDATE: Not, as commentator Anthony points out, due to any fault of the solar sails, but due to a rocket booster failure.)

(Image: John Ballentine.)

[tags]space exploration, solar sails, space travel, solar power[/tags]