Deployment Test of Solar Sail Film Conducted Using Sanriku Big Balloon

August 23, 2003

Announcement

Sanriku Big Balloon Experiment Team

At 6:27 a.m. on August 23 (Sat), 2003, as the first balloon of the FY2003 1st Big Balloon Experiment, the B30-71 balloon was floated from the Sanriku Balloon Center (SBC) to conduct the deployment test of the solar sail film structure. The solar sail is a future propulsion means in planetary space. 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 the experiment are 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 is 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 planned for FY2004. The two onboard video cameras operated normally and succeeded in recording the detailed images. They were recovered without problem and the imagery will be used to compare with the numerical simulation results.

The weather conditions on the ground at floating were fine with wind velocity of 1m/sec, and temperature at 18.5deg. C.