Japan’s “Solar Yacht” Is Ready to Ride Sunbeams Through Space
On May 18, the Japan Aerospace Exploration Agency (JAXA) says, it will launch into space a “solar yacht” called Ikaros—the Interplanetary Kite-craft Accelerated by Radiation of the Sun (named, of course, in honor of Icarus in Greek mythology). JAXA plans to control the path of Ikaros by changing the angle at which sunlight particles bounce off the silver-coloured sail [AFP].
Actually, the solar sail is a dual-purpose system, taking advantage of both the pressure and the energy of sunlight. The sail, which is less than the thickness of a human hair and 66 feet in diagonal distance, will catch the actual force of sunlight for propulsion as a sailboat’s sail catches the wind. But the solar sail is also covered in thin-film solar cells to generate electricity. And if you can make electricity, you can use it to ionize gas and emit it at high pressure, which is the propulsion systems most satellites use.
Potential velocity using a solar sailor has been theorized to be extremely high. “Eventually you’ll have these missions lasting many years, reaching speeds approaching 100,000 mph, getting out of the solar system in five years instead of 25 years,” said Louis D. Frieman, the Executive Director of the Planetary Society [Clean Technica]. The society has toyed around with its own solar sail.
For now, though, JAXA has a six-month test mission planned for Ikaros. If it works, they want to send a solar sail-powered mission to Jupiter and then the Trojan asteroids. That voyage would employ both the force of the sun and ion propulsion, and the Japanese are brimming with confidence: “Unlike the mythical Icarus, this Ikaros will not crash,” Yuichi Tsuda, an assistant professor at JAXA, said today [BusinessWeek].