Estudo de controle de empuxo em propulsores elétricos para aplicação em cubesats

Abstract

The following work is a study of thrust control in electrical propulsion for CubeSats. With emphasis on the review of the main technologies in electrical propulsion available for nanosatellites and an analysis of a real mission that demonstrates the practical application of these technologies in orbit. Initially, the fundamentals of electric propulsion systems are presented, organized into three categories, and discussed in terms of operational characteristics, advantages and limitations in the context of the severe restrictions on mass, volume, and power imposed by the standard CubeSat. Next, the concept of thrust control in open and closed meshes, along with the practical difficulties of its implementation in electrical micropropulsions. The central case study is about the satellite UWE-4, from the University of Würzburg in partnership with TU Dresden, which was the first CubeSat 1U to successfully operate an electrical propulsion system in orbit - the NanoFEEP, with gallium propellant. The attitude-hybrid system control, the neutralizers and propulsors characterization experiments performed in orbit, and the unprecedented orbital maneuvers performed are all detailed in 2020, which included altitude lowering and raising, and auto collision deviation. The results confirmed the viability of miniaturized electrical propulsion for CubeSat 1U and demonstrated that thrust control via current modulation is an effective approach for precise maneuvers in this class of satellite.