The Modular Relative Orbit Design Method for Spacecraft Proximity Motion

This paper presents a modular relative motion trajectory design tool for proximity operation of on-orbit service spacecrafts. First, a series of commonly used relative motion trajectories are defined. The dynamics are solved such that each type of trajectory is encapsulated into different modules. The input parameters of each module include the key geometrical features, such as the initial position, desired final position, and flying time. Different modules are connected via the same position and velocity. The modular orbit design tool is able to cover most of the typical proximity operation scenarios. Following that, two notational on-orbit service missions are given as examples to describe the specific usage process of the tool. It includes three major steps, namely, determining the appropriate module sequence according to the mission requirements, designing the pending input parameters of each module by taking consideration of constraints, and computing the details of module sequence to generate relative trajectories. Compared with the traditional maneuver-optimized orbit design approach, the modular method has fewer parameters to solve. Additionally, the modular application tool is versatile and can be used for a variety of different on-orbit service missions. This tool is of great importance in standardizing the space operations.