Solar sails are a proposed form of spacecraft propulsion using large membrane mirrors instead a rocket engine. It is pushed through space by light particles from the Sun reflecting off its giant sails. Althought radiation pressure is small and decreases by the square of the distance from the sun, the great advantage of this kind of vehicles is that they require no fuel.
The science of solar sails is well-proven, but the technology to manage large solar sails is still undeveloped.
The Kawaguchi Laboratory drives one research effort to develope such a vehicle specially focusing in craft's membrane unfolding and steering mechanisms both dinamyc and cuasi-static.
Balloon launched on: 8/23/2003 at 6:27 jst
Launch site: Sanriku Balloon Center, Iwate, Japan
Balloon launched by: Institute of Space and Astronautical Science (ISAS)
Balloon manufacturer/size/composition: Zero Pressure Balloon model B30 30.000 m3
Flight identification number: B30-71
End of flight (L for landing time, W for last contact, otherwise termination time): 8/23/2003 at 9:23 jst
Balloon flight duration (F: time at float only, otherwise total flight time in d:days / h:hours or m:minutes - ): 3 h 38 m
Landing site: On the sea 20 km E of Touni Bay, Japan
After vertical launch, the balloon ascended normally at a mean velocity of 270m/min and, 2 hours and 15 minutes after takeoff, it began level floating 40km east of SBC at an altitude of 35.8km.
At 8:56 a.m., the balloon released the solar sail experimental payload, and the deployment measuring experiment was successfully conducted.
After that, the balloon moved west, and the observation instruments were released from the balloon 7km east-northeast of Touni Bay by the command signal sent at 9:23 a.m.
The observation instruments descended slowly using the parachute and landed on the sea about 20km east of Touni Bay (Long.: 142° 10' E, Lat.: 39° 14' N).
The helicopter and recovery ship successfully recovered the balloon and instruments.
The objectives of this flight was to drop the folded polymer film, which is an almost round shape in 4m diameter at deployment, at revolutions of 60rpm, and simulate and measure the dynamic characteristics of deployment movement under the conditions of zero gravity and thin atmosphere.
The experiment was also designed to establish a method to simulate the numerically dynamic behavior of the thin film, which is not equipped with analysis tools, and serves as the preliminary test leading to the flight experiment by the sounding rocket done in 2004.
The two onboard video cameras operated normally and succeeded in recording detailed images of the deployment to be used to compare with the numerical simulation results.