Magnetic Attitude Control Scheme for Drag Sail Deorbiting with Limited Sensors

Abstract

As concerns over space debris in the Low Earth orbit (LEO) intensify, deorbit strategies for small satellites becomes evident because many lack an effective deorbit mechanism. After successfully demonstrating their effectiveness in flight tests, aerodynamic drag sails emerge as a superior deorbit solution, significantly reducing the time required for deorbiting. To maximize the aerodynamic drag, it is crucial to maintain the drag sail perpendicular to the atmospheric flow. This becomes especially challenging with the potential threat of sensor failure. This paper introduces a magnetic control scheme for deorbiting using drag sails. Relying solely on magnetometers as sensors, the control scheme uses magnetorquers, bias momentum wheels, and an onboard geomagnetic field model to keep the sail perpendicular to the satellite’s velocity. Furthermore, a backup control scheme that does not require the onboard geomagnetic field model is proposed. This control scheme uses magnetometers in conjunction with just another common small satellite sensor, such as the GPS, gyroscopes, or sun sensors as sensors. A stability criterion, based on a linearized analytical model, validates the feasibility of this backup control scheme. Numerical simulations confirm the efficacy of both control schemes. Both schemes reduce the deorbit time by approximately 40% compared to the uncontrolled satellite deorbiting.