The Japan Aerospace Exploration Agency (JAXA) launched the Ikaros solar sail today aboard the H-IIA Launch Vehicle (H-IIA F17). IKAROS is a space yacht that gathers energy for propulsion from sunlight pressure (photons) by means of a square membrane measuring 20 meters (65.6 ft) diagonally.
The Akatsuki special site at JAXA is here
The IKAROS won’t just employ a solar sail, but rather a “solar power sail” in that thin film solar cells on the membrane will be used to generate electricity. However, any electricity generated will not be used by the craft, as the goal of the mission is to verify acceleration by solar radiation and power generation of the thin film solar cells. If successful, JAXA then hopes to use the technologies to build an explorer that can travel to Jupiter by combining solar sail technology and a high-performance ion engine powered by electricity gathered by the solar cells.
The Venus Climate Orbiter AKATSUKI was separated from the H-IIA on May 21, 2010. IKAROS will travel towards Venus with the AKATSUKI for about a month, after which it will deploy its sail.