Published on August 11th, 2010 | by Tina Casey1
"Saran Wrap" Solar Sails are Powering New Space Exploration
Imagine the Starship Enterprise powered by safe, reliable solar energy and – well, okay so it’s a lot less dramatic than the dilithium crystal thing, but that’s the point: you get the speed without the risk because essentially, there’s no fuel. According to a gathering of scientists at the Second International Symposium on Solar Sailing, ultra-thin solar sails that are less than one-fifth the thickness of plastic wrap are the way to go for powering certain types of future space flights. The solar cells work by collecting the pressure generated by sunlight, just like a regular sail collects wind pressure.
Solar sail technology is advancing quickly, and deep space tests have already confirmed its viability: Japan’s solar sail-powered IKAROS was launched on May 21 and is on the first leg of a six-month flight around Venus, after which it will head off for the far side of the sun.
IKAROS and Solar Sails
Though perhaps the acronym is a little unfortunate (didn’t Icarus get too close to the sun and – oh well, never mind), it stands for Interplanetary Kite-craft Accelerated by Radiation of the Sun, which is basically how solar sails work. IKAROS’s sails consist of an aluminum-reinforced plastic membrane layered with thin-film solar cells. Photons of light reflect from the sail, pushing the spacecraft along while also generating electricity. In contrast to fuel cells, which achieve a certain speed and then are turned off to conserve fuel, the solar sails can continue to build speed. The membranes also include sets of LEDs, which “steer” the ship by changing color, controlling how much light is absorbed by different parts of the sail.
Solar Sails and the Future
When IKAROS was first launched, there was considerable anxiety as to whether or not the technology would actually work in flight. The Solar Sail Symposium, hosted by the New York City College of Technology, appears to have laid those fears to rest. A team of scientists from JAXA, Japan’s space agency, presented “stunning visuals” confirming that the membrane was successfully deployed and the craft was accelerating. In future projects, JAXA plans to send partially sail-powered spacecraft to Jupiter and the Trojan asteroid. Looks like the U.S. has some catching up to do – hey, good thing Congress just voted in favor of a bill to help local school districts with funds to avoid massive teacher layoffs, though to be honest almost the only representatives who voted for the funding bill belong to the current majority party. Other members of Congress are apparently more focused on cutting taxes for wealthy grownups rather than making an effort on behalf of educating the next generation of scientists.
Image: Plastic wrap by lylamerle on flickr.com.