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People smarter than us are saying the future of space travel may be in solar sailing. It's not a totally new concept, however, as Johannes Kepler's ideas about using solar wind to go great distances was first posited back in the 16th century.

But as technology has advanced, we've come to see that harnessing solar energy is a great lightweight way to drift at incredibly high speeds, utilizing the relative low drag of empty space and the gravitational slings of heavenly bodies to go large distances.

NASA's Voyager One which launched way back in the 70s is now about 10 billion miles from Earth traveling at 10.6 miles per second or 38,160 miles per hour. This ship, however, uses radioactive fuel instead of solar wind and just as its reaching interstellar space in 2025, it will run out of fuel and drift uncontrollably with no means to communicate with Earth.

There are 3 different types of space sails currently in the works, some of which will get their day in the sun very soon. Launching in under a week will be Nanosail-D aboard a Falcon 1 rocket. This solar powered sail, developed by NASA with the help of $30 million, will be the first ever deployed and tested in space. It takes the classic form of a sail as a 100 sq. ft. solar ray catching wall.

Pekka Janhunen at the Finnish Meteorological Institute is developing an electric sail composed of tiny aluminum or copper alloy wires that will catch the sun's energy and focus it into a gun propulsion system sending whatever it is attached to beyond the reaches of Pluto in under 5 years.

The third type of sail is magnetic and it's creation seems a little far off into the future. It proposes creating an electromagnetic field around an object, like a spaceship, and using the solar energy's deflection off the magnetic field to shoot the object at high speeds. The hitch is the superconducting wires to create a magnetic field of this much power has never been developed.

So, while this technology is a long time in the planning and merely in its infancy as far as implementation, Louis Friedman, executive director of the Planetary Society tells us that solar sails are, "the only technology that we know of that can one day take us to the stars."

sciam.com: Voyaging to the Stars on a Solar Breeze