On Earth, sails tap the wind's power to push ships across oceans. In space, solar sails use the sun's light to fly through space. See how solar sail technology has come of age in the 21st century in this gallery of actual space missions and potential future exploration.
The world's first solar sail to fly in deep space, Japan's Ikaros, is seen in this self-portrait view taken on June 14, 2010, after sail deployment.
The Sunjammer project, slated to launch in 2014, will demonstrate "propellantless propulsion" offered by solar sails.
An early prototype of L’Garde solar sail is evaluated in a vacuum chamber at the NASA Glenn Research Center’s Plum Brook Facility in Sandusky, Ohio. This test article is a quarter the size of the sail the company plans to fly in 2014.
This photo shows Japan's Ikaros solar sail as it sailed by the planet Venus (which appears as the crescent at upper right) on Dec. 8, 2010. The Ikaros solar sail was about 80,000 kilometers from Venus during the flyby.
A tiny cylindrical space camera detached itself from Japan's new solar sail and snapped some photos of the mission bound for Venus and beyond in June 2010.
NASA's NanoSail-D soars in Earth orbit in 2011 in this artist's illustration.
The Japan Aerospace Exploration Agency's Ikaros solar sail is seen in deep space after its deployment on June 14, 2010, in this view taken from a small camera ejected by the sail.
This image captured by skywatcher Arto Oksanen in Finland shows NASA's solar sail satellite NanoSail-D as it appeared in aurora-watching cameras on Feb. 24, 2011 at the Nyrölä Observatory.
Skywatcher Arto Oksanen snapped this photo of NASA's NanoSail-D solar sail while observing from the Nyrölä Observatory in Finland.
Japan's Ikaros became the first successful solar sail flight using sunlight propulsion, and the first interplanetary sail, during its 2010 mission.
A camera captures the second stage of solar sail deployment on the Japanese Ikaros mission. Four thin tethers that mechanically connect the solar sail membrane with the main body can be seen extending downward on both left and right sides of the image, while a harness that provides the electrical connection extends from the center to the lower left.
The world's first solar sail to fly in deep space, Japan's Ikaros, is seen in this self-portrait view taken on June 14, 2010, after sail deployment.
Led by L’Garde Inc., of Tustin, California, this Solar Sail demonstration will enable propellantless in-space navigation for missions such as advanced geostorm warning, economic orbital debris removal, and deep space exploration.
The Huntsville-based NanoSail-D team stands with the fully deployed sail at ManTech SRS technologies on April 16, 2008, after the successful deployment test.
Japan's Venus Climate Orbiter Akatsuki and the Ikaros solar sail launch into space atop an unmanned H-2A rocket on May 20 (U.S. Eastern Time) from Tanegashima Space Center in Japan. It was early morning Friday, May 21 at the Japanese launch site.
The H-2A rocket payload fairing containing Akatsuki and Ikaros was transported to the Vehicle Assembly Building over the weekend.
An artist's concept of the LightSail-1 spacecraft, which scientists hope will prove that sunlight can power a ship through space.
An illustration of how solar sails might help deflect the asteroid Apophis.
Space-based lasers could allow for interstellar missions by focusing beams on immense lightweight solar sails, allowing a spacecraft to reach enormous speeds.
Clean-up solution: solar sail, as seen in the movie "Space Junk 3D."
This graphic by the Japan Aerospace Exploration Agency depicts a potential solar sail mission to Jupiter propelled only by the sun's light.
An artist concept of an electric solar sail. The center package contains the solar panels powering an electron gun that keeps the many tethers charged.
An artist's illustration of the submarine-based rocket launch that aimed to loft a small solar sail into orbit for the Planetary Society.
A shot of a Minotaur 4 rocket carrying seven satellites - including a NASA solar sail - blasting off on Nov. 19, 2010, from a site in Alaska.
NASA engineers are testing solar sails, a unique propulsion technology which rely on sunlight to propel vehicles through space. The sail captures solar particles, called photons. This image is of a four-quadrant solar sail system, measuring 66 feet on each side, being tested in the world's largest vacuum chamber at NASA's Glenn Research Center at Plum Brook Station in Sandusky, Ohio.
