Jun'ichiro Kawaguchi

<p>The purpose of this work was to develop escape trajectories from distant retrograde orbits in the Sun&ndash;Earth circular restricted three-body problem. Previous studies have suggested installing a space port outside the gravitational sphere of influence of Earth for future deep space exploration. This paper proposes the placement of a space port on a Sun&ndash;Earth distant retrograde orbit (SE-DRO), which is stable over a long period. The characteristics and fuel consumption efficiency of escape trajectories from the space port on the SE-DRO using one or two impulses &Delta;V were investigated and compared with those obtained in previous studies that considered a space port located in the vicinity of the Sun&ndash;Earth L2 Lagrangian point. The connection of the escape trajectories from an SE-DRO with Earth gravity-assist (EGA) trajectories was then investigated based on the results of the analysis with the impulse &Delta;V. Finally, a series of trajectories from SE-DRO to EGA were shown to have a high efficiency from the perspective of both &Delta;V and the flight time.</p>

Attitude control methods of a solar sail which maximize the effectiveness of ΔVEGA (ΔV Earth Gravity Assist) are proposed. An orbit of a solar sail is controlled by changing its attitude, and there are two types of method to control an orbit of a spinning solar sail. One is to control its attitude directly, and the other is to control its attitude indirectly using an attitude drift motion due to the solar radiation pressure by controlling its spin rate. These methods are applied to an orbit of ΔVEGA, and their efficiency is quantitatively evaluated by solving optimal control problems to maximize the relative velocity with respect to the Earth.