IKAROS, described by its developers as a “kite craft”, gathers sunlight as propulsion by means of a large sail. The spacecraft will be launched together with the Venus Climate Orbiter, "AKATSUKI"(PLANET-C), using the H-IIA launch vehicle. Costing around 1.5 billion yen (€12 million), it will be the world's first solar-powered sail craft employing both photon propulsion and thin-film solar power generation during its interplanetary cruise. IKAROS's square, sail-like membrane, which has a diagonal width of 20 metres and is covered in a film of solar cells about 32.5 micrometers thick (approximately half the thickness of a human hair),will be wrapped around the “space yacht” during lift-off and will unfurl once the craft leaves the Earth’s atmosphere, JAXA said.
The destination of the IKAROS space yacht has not been defined, although JAXA reveals that it will be flown toward Venus. “Unlike the mythical Icarus, this Ikaros will not crash,” Yuichi Tsuda, an assistant professor at JAXA, told Bloomberg recently.
The sail will propel IKAROS using resistance created by energy from the sun in much the same way as wind propels a yacht through water. Photons, or solar energy particles, bounce off tiny mirrors, providing enough thrust for satellites to perform manoeuvres such as hovering and rotating, JAXA said.
Ion propulsion
In the same way as conventional satellites, solar sails can also use ion propulsion, with the solar panels generating electricity to ionize gas, which can then be emitted by the spacecraft at high speed to thrust the satellite, National Aeronautics and Space Administration in the US explains on its website.
The Planetary Society is also developing a spacecraft called LightSail-1, which will sail on the earth revolving orbit by the end of 2010. The Planetary Society is one of the biggest organisations in the world promoting space exploration.
LightSail-1 is an ultra-light spacecraft with a mass of less than 5 kilograms. With a sail area of approximately 32 square metres, its goal is to fly in Earth’s orbit to demonstrate that attitude and orbit can be controlled and velocity increased using the sun’s energy.
Bloombery reports that NASA and the Russians are also exploring solar-sail technology, which can create lighter and smaller craft than conventional satellites.
IKAROS’s mission will conclude within six months, and JAXA plans to launch a larger sail-powered satellite in the early part of the next decade to explore Jupiter and the Trojan asteroids.
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