Non-profit group Icarus Interstellar is devoted to finding a way to travel to another star system and they believe the future is in solar sails; these feats of engineering would be 100 kilometers or larger and could make an interstellar voyage in 1,000 years. While this may seem like a long time to you and I, it is certain that if one were launched, someone would be on the receiving end of the radio-transmitter for the 1,000 years to come. The group believes that solar sails are the future as fusion power has not yet been developed to a usable extent, and the other alternative, anti-matter rockets, suffer from a serious design flaw and a lack of fuel.
Solar sails aren’t as new as you may think, nor are they a piece of speculative science fiction. There have been mentions of such a device as far back as Johannes Kepler, James Maxwell, Jules Verne, Albert Einstein and many others, and as a proof of concept in 2010 Japan launched the first interplanetary spacecraft with solar a solar sail as a primary propulsion system, IKAROS. IKAROS deployed a 200m2 solar sail and spent 6 months travelling to Venus and then begun its three-year journey to the far side of the Sun.
It has been calculated with a few assumptions that the maximum thrust available to a craft would be 0.01 Newtons. This is very small, but when taken to account of an extended period of time, this could amount to a velocity much greater than that provided by any conventional rocket. In order to further the research in this area NASA plans to launch a spacecraft, Sunjammer, in 2014 which will feature the largest solar sail to date which will measure 38m across.