On Keeping the Distance between Space Stations Tethered by a Handrail

Relative motion in a system consisting of two massive heliocentric space stations and a small mass spacecraft equipped with a solar sail is considered. The system is approximately 1 AU from the Sun. The spacecraft is capable of coasting along a tether (called a “handrail”) connecting the stations, and the sail is oriented orthogonally to the solar rays direction. The distance between the stations is assumed to be about a few kilometers. The stations are equipped with additional solar sails that help compensate the influence of the spacecraft motion on the relative location of the stations. The conditions providing such compensation are deduced. These conditions allow one to determine the area and orientation of additional solar sails so that the distance between the stations keeps invariable, and the segment connecting the stations remains orthogonal to the solar rays after the spacecraft relocation between the most remote points permitted by the handrail. The conditions are verified numerically by comparing the solutions of the equations of motion with and without taking into account additional sails.