Equilibrium and station-keeping efficiency of cross-track multi-satellite arrays using a micro-electromagnetic formation flight

Abstract

Electromagnetic formation flying is a novel concept of controlling the relative degrees of freedom of a satellite formation without the expenditure of fuel by using high-temperature superconducting wires to create magnetic dipoles. Micro-electromagnetic formation flying, which is an alternative to electromagnetic formation flying in terms of reduced complexity, uses conventional conductors to replace the high-temperature superconducting coils in electromagnetic formation flying, shortening the separation distances between the electromagnets. This paper investigates the use of micro-electromagnetic formation flying for providing relative position control for unperturbed station-keeping in a multi-satellite array along the cross-track direction that can be used in cross-track interferometric synthetic aperture radar applications. Considering that conventional conductors produce small separation distances between electromagnets, comparatively large baselines can be achieved by positioning multiple satellites consecutively in an array. The existence of equilibrium positions of the satellites is demonstrated. The station-keeping efficiency of the formation satellites is studied. It is found that the electromagnetic dipoles on neighboring satellites should be equal in magnitude and opposite in direction to obtain the maximum station-keeping efficiency of the formation; correspondingly, the equilibrium positions of the satellites along the cross-track direction are symmetrical about the center of mass of the formation. A method for maximizing the station-keeping efficiency of the formation using micro-electromagnetic formation flying is also presented, using feasible designs for small satellite formations as examples.