Transformable spacecraft: A system with variable-shape structure applicable to nonholonomic attitude control

Abstract

As an innovative spacecraft system, a transformable spacecraft is proposed, which consists of multiple bodies connected with each other. They are equipped with actuators that move them relatively within a certain range of angle. The shape of the bodies is arbitrary, and the simplest is panel shape, for example. Supposing a transformable spacecraft consisting of a number of panels, they can be folded to be compact as a whole, unfolded to configure a large plane, and recomposed to configure various kinds of three-dimensional shape. The system enables a single spacecraft to have multiple functions by transforming the shape. A distinctive characteristic of a transformable spacecraft is its capability of performing nonholonomic attitude control. By transforming to another shape and transforming back to the original shape in a different path, the attitude is changed even if the shape is unaltered. This nonholonomic control is realized only by internal torque, and does not require any fuel consumption. We introduce the concept of a transformable spacecraft and its applications to missions, utilizing the nonholonomic control. For example, combining the function of variable-shape structure with the nonholonomic control, a multifunction space telescope can be realized orbiting around the Sun-Earth Lagrange point. Show more