The past two decades have seen an increasing interest in Hall thrusters in space propulsion, thanks to their favorable performance characteristics with respect to a wide variety of missions of current and future interest and to the significant extension in operational life potential achievable with magnetic shielding. Nevertheless, the physics underlying their behavior is complex and not yet fully understood, limiting the practical applications of models based on first principles due to their inability to self-consistently predict the device performance. Fortunately, modern Hall thrusters were developed through a lengthy process of gradual refinement, and thus they represent convenient reference devices to design new thrusters using appropriately defined scaling criteria. The objective of this work is to propose a new scaling methodology, especially intended for magnetically shielded high-power Hall thrusters. To this purpose, a novel phenomenological model for shielded thrusters is presented and discussed. This model includes free coefficients, whose values are chosen based on the agreement with the empirical data collected in a specially created high-power Hall thruster database. The proposed methodology features a new reference thruster and aims at keeping unchanged its main plasma intensive parameters in a scaling transformation. The possibility of creating performance maps at constant discharge power, which show how the scaling results vary with the channel dimensions, is also proposed as a preliminary design tool.

Manufacturing and testing electric propulsion systems can be very expensive both in economic and time terms. One of the main limiting factors is the manufacturing of ceramic components, such as alumina. However, the advent of 3D printing has made it possible to produce complex-shaped components made of technical ceramics at low cost and in reduced time. This paper illustrates the advancements made by the University of Pisa in Fused Filament Fabrication of alumina components for electric propulsion purposes. Rapid prototyping can help not only in manufacturing thrusters in a faster and cheaper way but also in producing more complex geometries, resulting in more efficient thrusters. The alumina produced through this method has achieved near-full density and a flexural strength of 430 MPa. Components manufactured with this technique successfully passed vibration and pyroshock tests. This manufacturing approach was already used in the framework of the CHEOPS-VHP-BB (Consortium for Hall Effect Orbital Propulsive System-Very High Power-Building Blocks) project to produce the insulating components of a high-current hollow cathode.