Japanese solar sail Ikaros unfurls successfully in space

Japanese scientists are celebrating the successful deployment of their solar power sail, Ikaros, which will demonstrate the principle of using sunlight as a simple and efficient means of propulsion in space.

The technique has long been touted as a way of moving spacecraft around the solar system using no chemical fuels, the BBC reports. To evaluate the method in practice, the mission team will be watching to see if Ikaros produces a measurable acceleration, and how well its systems are able to steer the craft through space. The 200-square-metre (2,100 square feet) membrane is attached to a small disc-shaped spacecraft that was put in orbit last month by an H-IIA rocket. The Japan Aerospace Exploration Agency (Jaxa) said in a statement that its scientists and engineers had begun to deploy the solar sail on 3 June (JST) about seven million kilometres from Earth. Confirmation was received on June 10 that the sail had expanded successfully and was generating power through the thin-film solar cells embedded in the membrane. Space applications Solar sails will never replace conventional propulsion systems like chemical thrusters, but they do have the potential to play a much greater role in certain types of space mission. Louis Friedman, from the space advocacy group The Planetary Society, is a big supporter of the technology. The society's LightSail-1, a much smaller mission than Ikaros, could launch by the year's end. He told BBC News recently: "The potential that we all seek is the ultra-lightweight, very fast spacecraft that doesn't use fuel.” Already some satellites in geostationary orbit above the Earth use flaps on the ends of their solar panels to catch the pressure of sunlight to maintain their correct attitude. This leads to a considerable saving on the fuel that would otherwise have to be sent surging through the satellites' thrusters, and operators have found this strategy can extend the longevity of some missions by many months.