I'm sailing on sunshine

Lookee here at an actual picture of a solar sail in action. The Japanese launched their IKAROS ship back in May, and its now successfully using the force of the solar wind to make its way to Venus (it also has an ion engine, and this combo - ion engines with solar sails - could prove remarkably effective for longer range space travel).


Solar sails work exactly like wind sails work here on Earth, except of course using photons instead of wind to derive thrust. Once unfurled, they use almost no power to operate, and thus you see their benefit - you don't have to bring much fuel.

The force of the solar wind is truly minuscule, but it's also cumulative, such that while you are only receiving a very small amount of push on the sail, it just gets faster and faster since there is no friction to slow it down. Thus, after a relatively short period of time, the solar sail begins to really pick up speed. If it were allowed to continue, it would just get faster and faster.

Here's an image of how the solar sail works:

Of course, the solar wind does not look like this, but rather, as with most diagrams, is a sphere of energy expanding in all directions, with some directions receiving more force based on activity on the sun.

This is all very promising. Since America is pretty much dropping out of the space game (except for the military, of course), I guess we'll have to rely on the Japanese, Chinese, and Indians to advance the ball further. Go Team!