{Science} First 'solar sail' prepares for launch

[BEER980]

First 'solar sail' prepares for launch

By Dan Vergano, USA TODAYMon Jun 20, 7:00 AM ET

A space advocacy group is hoping to show the world a new way to power vehicles through space by launching the first "solar sail" into orbit Tuesday. If successful, the privately launched Cosmos 1 will pioneer an elegant method of space travel that uses gentle pressure from sunlight to ply outer space. In theory, the impact of each light particle, or photon, from sunlight on the spacecraft's sails will propel the probe through space's airless, near-frictionless vacuum.

The mission has a cast of characters not usually featured in space missions. NASA experts have been consulted and are interested in the data, but the Planetary Society, based in Pasadena, Calif., is sponsoring the launch of the $4 million experimental spacecraft. Half of the money is provided by Cosmos Studios, a maker of science documentaries that is chronicling the mission. Because fuel takes up much of the weight of satellites, solar sails made of stronger modern materials have captivated space enthusiasts.

If the launch from a Russian submarine in the Arctic Barents Sea goes well, the 220-pound experimental Russian-built spacecraft will reach a 500-mile-high orbit. After it circles Earth for four days snapping photos, its eight sail blades, made of aluminum-backed plastic about one-quarter the thickness of a trash bag, will unfurl into a 100-foot wide circle. The unfurling of the sails is the riskiest part of the mission; the material could rip or tangle.

Once the sails unfurl, mission controllers will attempt the first space navigation propelled by the pressure of sunlight. By turning the sail to different angles from the sun's light, the spacecraft should be able to raise and lower its orbit. The sail will be visible at night, shining as brightly as a full moon, but smaller. The craft is set to circle the Earth once every 101 minutes for weeks. Sunlight pressure on the sails may only increase the speed of the satellite up to 100 mph each day, but that adds up over time. Proponents believe that in the future, the constancy of sunlight pressure will make interplanetary solar sails much faster - and cheaper - than those propelled by rocket.
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[abajan]

...Sunlight pressure on the sails may only increase the speed of the satellite up to 100 mph each day, but that adds up over time. Proponents believe that in the future, the constancy of sunlight pressure will make interplanetary solar sails much faster - and cheaper - than those propelled by rocket...

As a matter of fact, this method has been seriously proposed as a way to attain travel at the speed of light!