Physical optimisation of ion thruster plume behaviour

Ion thrusters can be used on a variety of space missions, with applications including precision pointing, orbital adjustments, constellation control and maintenance, debris removal and deep-space exploration. Due to several demonstrator missions illustrating their reliability and cost benefits, there has been an increase in investigation and growth in the ion thruster sector and in the electric propulsion in space sector.

The goals of this research project include the total overall efficiency in respect to the performance of the thruster and to develop a novel thrust vectoring mechanism. The thrust vectoring will further optimise the spread of the plume that is formed by the ions leaving the thruster, by changing the physical design of existing ion thrusters and therefore, further develop current state of the art technology.

This will result in aiding overall possible mission application due to the thrust vectoring mechanism. Being able to minimize or control the formation of plasma sheath around a spacecraft and other degradation effects caused by the ions leaving the thruster, will result in the spacecraft being operational for a longer period.

Aims and Objectives This research aims to modify and optimise the current design of state-of-the-art ion thrusters, with a

mixture of plasma physics, numerical modelling, artificial intelligence, and general aerospace engineering approach to maximise performance, efficiency, and lifetime. Modified ion thruster designs will be proposed by setting an initial criterion to adapt to current existing CubeSat dimensions, and evaluated to choose the most efficient design. These simulations will be performed in a 3D numerical code which will be developed at the start of the project, and consequently a study will be performed to choose the optimum numerical methods to model the plasma physics in the system.

Furthermore, the use of artificial intelligence will be explored later in the project, to perform not only design optimisations, but also a type of time-series forecasting to predict the sheath formation and other degradation effects present in the spacecraft caused by long-term use of an ion thruster. This research project will address the following questions:

What is the best numerical method to simulate the ion thruster mechanism? What is the optimum algorithm for particle interaction modelling for this application? How can the propulsive efficiency and plume behaviour of current state of the art ion thruster technology be improved? What effect on the environment will different propellants in the new thruster have?

How will the performance of the thruster vary whilst changing altitude in a low Earth orbit and how does this compare with existing thrusters? What parameters is the numerical simulation of an ion thruster most sensitive to and how can this be improved? Methodology

The novelty in the proposed design is that it uses an external piece of hardware to enable thrust vectoring whilst not requiring any redesign of the thruster. Additionally, the use of AI would be a novel approach to electric propulsion modelling, to observe degradation effects over the spacecraft potentially caused by an ion thruster, without having to perform heavy computational simulations.