Basic Study on Attitude Control around Unstable Equilibrium Point Using Solar Radiation Pressure of Transformable Spacecraft

Abstract

JAXA plans to apply transformable spacecraft to a space telescope that performs astronomical observation. It is necessary for the telescope to keep pointing in the same direction (attitude) with high precision for a certain period of time for observation. Here, a transformable spacecraft refers to a spacecraft that can change its shape. Conventionally, the attitude of a spacecraft has been disturbed by solar radiation pressure. However, in the transformable spacecraft, it is expected that by changing the structure of the spacecraft, it is possible to control the influence of solar radiation pressure and to perform attitude control using it. In the transformable spacecraft, the equilibrium point can be obtained by changing the shape with respect to an arbitrary angle. At the equilibrium point, the moment of attitude change caused by solar radiation pressure is small, which is an advantage. Therefore, the equilibrium point is an important point for attitude stabilization. In this research, an initial study on highly stable attitude control around an unstable equilibrium point using solar radiation pressure by a deformable spacecraft is performed. Since it is expected that the calculation will be complicated by three dimensionalization, a study using reinforcement learning will be performed to realize attitude control that does not require a model.