Propulsion-Free Cross-Track Control of a LEO Small-Satellite Constellation with Differential Drag

TL;DR

This paper demonstrates a propellantless method for controlling satellite formations in low-Earth orbit by manipulating atmospheric drag and Earth's gravitational field, enabling large separations over months.

Contribution

It introduces a linear programming-based algorithm for propellant-free formation control using differential drag and gravitational effects in a receding-horizon scheme.

Findings

Achieved hundreds of kilometers separation in months

Validated control scheme in high-fidelity simulations

Demonstrated propellantless cross-track and along-track control

Abstract

In this work, we achieve propellantless control of both cross-track and along-track separation of a satellite formation by manipulating atmospheric drag. Increasing the differential drag of one satellite with respect to another directly introduces along-track separation, while cross-track separation can be achieved by taking advantage of higher-order terms in the Earth's gravitational field that are functions of altitude. We present an algorithm for solving an n-satellite formation flying problem based on linear programming. We demonstrate this algorithm in a receeding-horizon control scheme in the presence of disturbances and modeling errors in a high-fidelity closed-loop orbital dynamics simulation. Our results show that separation distances of hundreds of kilometers can be achieved by a small-satellite formation in low-Earth orbit over a few months.