Deployment Test of Solar Sail Film Conducted Using Sanriku Big Balloon
As one means of propulsion for the future deep space explorer, the Institute of Space and Astronautical Science (ISAS) is conducting research on the "Solar Sail", which is driven by the force of photons in sunlight. ISAS recently conducted an experiment using the Sanriku Big Balloon to drop the thin-film structure mocking solar sail from an altitude of 35km, and monitor the behavior of the thin-film deploying in zero gravity (free fall). The film, 0.03mm in thickness and 4m in diameter, deployed by centrifugal force as planned.
August 23, 2003
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.
Images of solar sail deployment recorded by video camera
August 26, 2003