Two spacecrafts are now sailing through space, powered in part by the sun. Both vessels use large but thin polymer sails to capture photons that help propel them. I wrote about Japan's sail-craft named Ikaros last April shortly before it launched. Ikaros is currently somewhere around Venus. Closer to home, NASA's NanoSail-D is now circling Earth at a low orbit.
Much of the buzz surrounding the solar sails is that the technology may one day lead to vessels with limitless power to explore deep space.
The Christian Science Monitorreports:
It may lack the pizzazz of warp drive, the fictional propulsion system known to Star Trek fans. But many of its advocates argue that solar sails represent the best path to eventual interstellar travel. More immediately, the technology also holds the promise of reducing the amount of space junk orbiting Earth, boosters say.
For now NanoSail-D's mission is to deploy, deorbit, demonstrate and drag. (These are what the "D" stands for.) Sometime within the next four months, the sail-craft will re-enter Earth's atmosphere and burn. Meanwhile, Ikaros will continue cruising deep space (where less drag makes the sailing smoother and faster) until spring of next year.
Only 0.0075 millimeters thick in some places, Ikaros’ sail is 46 square feet. Yuichi Tsuda of Japan's space agency JAXA explained last spring that the sun’s radiation propels Ikaros via the pressure placed on the sail as well as provide the vessel with electricity. JAXA steers the craft by angling the way solar particles hit the sail.
Other applications for solar-propelled spacecraft, discussed recently in Nature, might include monitoring for solar flares and aiding communication between a lunar base and Earth. The author quotes John West of NASA's Jet Propulsion Laboratory:
But if future solar-sail demonstrations succeed and electronic technology shrinks, allowing for even smaller and lighter probes, the propulsion method is certain to see some action, says West. "There's a niche for solar sails and it's there for the taking."
The Planetary Society hopes to launch in June its own solar sail, LightSail-1.
Related on SmartPlanet:
Image: NASA, JAXA
This post was originally published on Smartplanet.com