DYNAMIC MODELING AND EXPERIMENTAL VERIFICATION OF POINTING CONTROL TECHNOLOGY IN BALLOON-BORNE TELESCOPE SYSTEM FOR OPTICAL REMOTE SENSING OF PLANETS

摘要

Tohoku University and National Institute of Polar Research are carrying out the project of the optical observation of Venus using a balloon-borne telescope. The pointing technology with only 0.1-arc-second precision to restrain the slight moving of image is being developed. In this paper, the dynamics model is defined, and the model parameters are determined by the experimental verification. By developing the numerical simulation tools, the motion in different structure and device configurations can be rapidly estimated. The astronomy observation by a stratosphere balloon has been being conducted, and it can reach the 30-km altitude. Compared to spacecrafts, they have the advantageous of cost. Because the balloon-bone telescopes do not experience the extreme environment, the commercial off-the-shelf laptop computers can be carried just as it is, and the devices can be collected after the finish of flight. The previous missions for Venus atmosphere are not sufficient. The high-speed west wind called super-rotation has been confirmed which reaches the 60 times speed as the Venus rotation. To solve this mechanism, the optical observation with high quality and resolution is necessary. In this project, the technical demonstration flight for about 10 hours is conducted in May 2007 at Sanriku Balloon Center (SBC) in Japan. Secondly, the long-term flight for several tens of days is planned in 2008 at Kiruna in Sweden. The target precision of control is defined as 0.1 arc seconds. A commercial off-the-shelf telescope with a 30-cm primary mirror and a camera are used. The target precision is similar as Subaru Telescope in Hawaii and Hubble Space Telescope (HST), and this high precision has not been achieved in previous balloon-borne telescopes. The pointing control is classified to three stages. Firstly, the solar panel is controlled to the solar direction in the precision of 0.1 degrees.