Design of Space Systems

The course is focused on Electric Space Propulsion, as the new leading technology for in-space propulsion both in Near-Earth and Inner-Solar system applications. The goals of the course are that the students acquire a solid understanding of - the benefits and limitations of electric rocket propulsion versus classical chemical rocket propulsion, for different missions, and from microsatellites to large platforms. - the different types of electric thrusters and their main principles of operations - the main plasma physics concepts inherent to these thrusters - the derivation of performance models to support design, testing, and optimization of these technologies - the main technological constraints found in practice

1. FUNDAMENTALS OF ELECTRIC PROPULSION Figures of merit for propulsion. Specific thrust versus specific impulse. Chemical versus electric propulsion(EP). Optimal specific impulse. Missions for EP: main types, historical milestones. Plasma generation and acceleration mechanisms. The EP family of thrusters 2. PLASMA PHYSICS APPLIED TO PROPULSION Maxwell equations. On plasma typical units. Quasineutrality. Debye sheaths and plasma-surface interaction. The velocity distribution function and Boltzmann equation. Multifluid formulations. Main collisional processes (elastic, ionizing, Coulomb, CEX). Magnetized particle dynamics. Magnetized fluid dynamics: generalized Ohm and Fourier laws. 3. GRIDDED ION THRUSTERS Principles of operation: discharge chamber, grids, hollow cathode. The electric circuit. Global model of discharge chamber: plasma production, current and power balances, magnetic confinement. Inter-grid physics; the Child law. Plasma plume expansion. Performance laws. Thermionic emission. Hollow cathode physics. Thruster lifetime 4. HALL EFFECT THRUSTERS Principles of operation. Experimental characterization. The 2D multifluid formulation. Anomalous diffusion. Anode sheath. Secondary electron emission at ceramic walls. The simplified 1D model: formulation and solution. Global performance analysis and thrust mechanisms. Wall sputtering. Thermal loads. Plasma and circuit oscillations. Design of magnetic circuit. Alternative configurations (TAL, cylindrical, two-stage, HEMP) 5. ADVANCED PLASMA THRUSTERS Magnetoplasmadynamic thruster (with self and applied fields) The helicon plasma thruster: RF production and magnetic nozzle acceleration. Micropropulsion.

They combine - lectures with audiovisual support - discussion and solving of exercises and problems - homework assignements - quizzes Tutorials can be both personally or through Aula Global