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For the demonstration and verification of solar power satellite's functions, a small demonstration solar power satellite has been examined by USEF and ISAS/JAXA. Structural characteristics and attitude motion in steady operation have already been studied. In this paper, deployment sequence for the stable and fast deployment is investigated. The deployment sequence consists of two-stage truss extension and two-stage panel deployment. At first, attitude motion in the deployment is analyzed through numerical simulations. From the result, it is shown that nonlinear effect can not be negligible when pitch angle exceeds about 0.6 rad. In such a case, because independency of the pitch angle does not hold true for the nonlinearity, pitch motion leads to the large roll and yaw motions. Next, to realize stable and fast deployment, optimization of the deployment is carried out by changing each deployment time, interval and acceleration of the deployment. As an objective function, weighted sum of deployment times, maximum amplitudes of attitude angles and residual amplitudes of attitude angles is used. The optimization is carried out by Powell's method. From the result it is shown that maximum amplitudes of attitude angles are kept within 0.08 rad, and residual amplitudes of attitude angles are kept within 0.01 rad without any active control if about five orbital periods (about eight hours) can be spent for the total deployment., 資料番号: AA0049120010

A SPS (Solar Power Satellite) which is a part of the Space Solar System (SSPS) project has been studied at the USEF. Quasi-static analysis had been carried out for the practical SPS. The present purpose is to evaluate the attitude stability of the SPS under construction. During construction, it is assumed that the modules of 100 x 95 sq m are arranged in the shape of line. As the result of quasi-static analysis, it is shown that the roll and yaw angular frequencies of attitude motion are twice and once as large as orbital angular velocity in first step of the construction, respectively. Furthermore, as the result of dynamical analysis, amplitudes of the roll and yaw angles tend to divergence in first step. To avoid such a divergence, another model was proposed which is constructed keeping similar configuration. The construction way is called construction with similarity. From the result of simulations, it is shown that divergences in the roll and yaw angles can be avoided in the construction with similarity. However, the stability around the pitch and yaw axes are weak in first step for construction with similarity. In particular, maximum amplitude around the pitch axis is 5 deg. Therefore, both constructions need active attitude control because there are problems in first step of the constructions., 資料番号: AA0047275019