Simultaneous CubeSat attitude and orbit control using interaction between magnetic actuator and space environment

Abstract

Recent advances in CubeSat technology has shown CubeSat a promising platform not only for space education, but also in its potential in the use for valuable space missions. The value of CubeSat is added when utilizing the low-cost and fast-delivery advantage in operating multiple CubeSats together as a distributed satellite system (DSS) to perform multi-point observation or measurement missions. Depending on how the DSS is configured, valuable missions that conventional monolithic spacecraft could not perform can be realized. In order to take DSS advantage, orbit maneuver capability of CubeSats is required. Various conventional orbit maneuver methods for CubeSat exists, however the methods have its advantages and disadvantages. <br/> In this dissertation, a novel plasma drag interaction using onboard magnetic torquer with space plasma for CubeSat is proposed. Plasma drag constellation takes all the conventional advantages while providing accurate orbit deployment capability to CubeSats. <br/> An elementary analysis is presented as proof-of-concept. Numerical analysis on plasma drag constellation is performed for parametric study and elementary analysis validation. The results show the feasibility of the proposed method and the relationship between magnetic moment, desired phase angle, and satellite mass with deployment time. <br/> Practical aspects of plasma drag constellation are further analyzed as part of feasibility study. Feasibility diagram is derived based on CubeSat resource limitations and orbit plane perturbation. An example case of plasma drag constellation proves the feasibility of CubeSat using plasma drag constellation. Attitude disturbance problem is considered as another practical issue. The effect of magnetic torquer actuation that drives the satellite attitude unstable is examined. As a mitigation, high frequency polarity switching controller for torque cancellation is proposed. Numerical simulation results show that angular velocity was significantly decreased, however attitude remained unstable. As a solution, a high-frequency switching PD controller is proposed. The PD controller is designed to dump out the residual torque during polarity switching. Simulations show that the proposed high-frequency switching PD controller successfully stabilizes satellite attitude during the magnetic actuation while using magnetic plasma drag for orbit control.