From the Series
Renewable energy has become the cornerstone for a number of innovative designs, the evidence of which can be seen in Japanese missions into deep space. Just a few years ago, the Japan Aerospace Exploration Agency (JAXA) launched Ikoras – a solar sail spacecraft, powered by sunlight.
Ikaros, short for Interplanetary Kite-craft Accelerated by Radiation Of the Sun, is also called a space yacht. “A solar sail is propelled by sunlight instead of wind, so it's a dream spaceship - it doesn't require an engine or fuel,” says Jaxa.
Part of craft’s sail is covered in a solar cell made of an ultra-thin film, which generates electricity from sunlight. The square sail is 14 metres long on each side and the solar cell is made of a 7.5 micrometres thick film – a human hair is 100 micrometres thick.
Ikoras was deployed in June 2010 by unfurling its kite-like shape. Jaxa engineers used spin to unfurl the device at 25 revolutions per minute, using its weighted points in microgravity.
Engineers later discovered that they could control Ikaros using liquid crystal panels at the fringes of the sail.
"Jaxa will continue the attitude control experiment by the Ikaros to evaluate the details of the attitude control performance while continuing to conduct research on attitude control technology using sunlight pressure as a technology that enables navigation for longer in time and further in distance by a solar sail," said officials after the successful launch.
The solar sail’s mission is to explore the sun after taking a detour around Venus. It piggybacked aboard the main launch of Japan's Venus climate orbiter, called Akatsuki ("Dawn" in Japanese).
Akatsuki did not successfully complete its mission to Venus, and engineers are expected to make another attempt later this year.
The hope is that scientists will be able to use solar sails like Ikoras to explore the farthest reaches of our solar system. Ikoras is currently about 110 million kilometres away from the Earth, and about 130 million kilometres from the sun. It is expected to come out of its fifth hibernation mode later this year.