1. ELECTRIC PROPULSION Introduction Classification of Electric Thrusters Professor, Department of Aerospace Engineering, University of Pisa, Italy Chairman and CEO, Alta S.p.A, Via A. Gherardesca 5, 56121 Ospedaletto, Pisa, Italy e-mail: m.andrenucci@alta-space.com Mariano Andrenucci

2. Slide 2.2 Introduction ESA/ESTEC, Noordwijk, September 15-19, 2008 Advanced Course: Electric Propulsion Concepts and Systems M. Andrenucci Expansion of human presence in space will certainly pose the need to develop very high power propulsion systems High power electric propulsion can enable sending probes to the edge of the Solar System, exploring Kuiper belt, Oort Cloud, Heliopause, and performing deep Space observation… High Isp propulsion needed for the higher energy missions, with Isp levels of 10,000 s to 15,000 s to minimize launch mass High power levels also needed for crewed planetary exploration vehicles, but larger thrust leves required for acceptable trip times High power applications to be generally based on nuclear power systems; high performance photovoltaic power generation also applicable for inner solar systems operations Higher power propulsion systems obtainable in principle by clustering; but 0.1 to >1 MW single thruster capability needed so that the number of thrusters per spacecraft is reasonable. Introduction

3. Slide 2.3 Introduction ESA/ESTEC, Noordwijk, September 15-19, 2008 Advanced Course: Electric Propulsion Concepts and Systems M. Andrenucci Propulsion Options Among the various electric propulsion concepts, several types of devices provide, in principle, the ability to process hundreds of kilowatts to megawatts of power at reasonably high efficiencies Ion thrusters Plasma thrusters Hall Effect Thrusters MPD Thrusters Arcjets Other Concepts VASIMR Pulsed Inductive Thrusters... Among the above categories only the first two seem to meet the relevant selection criteria for the intended missions in terms of performance capability, lifetime potential, mid-term TRL,... Ion thrusters, in particular, appear especially suited for very high Isp, while plasma thrusters allow achieving higher thrust densities

4. Slide 2.4 Introduction ESA/ESTEC, Noordwijk, September 15-19, 2008 Advanced Course: Electric Propulsion Concepts and Systems M. Andrenucci Propulsion System Classification

5. Slide 2.5 Introduction ESA/ESTEC, Noordwijk, September 15-19, 2008 Advanced Course: Electric Propulsion Concepts and Systems M. Andrenucci Propulsion System Classification

6. Slide 2.6 Introduction ESA/ESTEC, Noordwijk, September 15-19, 2008 Advanced Course: Electric Propulsion Concepts and Systems M. Andrenucci Propulsion System Classification

7. Slide 2.7 Introduction ESA/ESTEC, Noordwijk, September 15-19, 2008 Advanced Course: Electric Propulsion Concepts and Systems M. Andrenucci Propulsion System Classification

8. Slide 2.8 Introduction ESA/ESTEC, Noordwijk, September 15-19, 2008 Advanced Course: Electric Propulsion Concepts and Systems M. Andrenucci Performance Levels

9. Slide 2.9 Introduction ESA/ESTEC, Noordwijk, September 15-19, 2008 Advanced Course: Electric Propulsion Concepts and Systems M. Andrenucci The Thrust-Density Issue SF-MPDT: 10 3 AF-MPDT: 10 2 GIT: 10 0 HET: 10 1 Order of magnitude Source: IRS, Stuttgart

10. Slide 2.10 Introduction ESA/ESTEC, Noordwijk, September 15-19, 2008 Advanced Course: Electric Propulsion Concepts and Systems M. Andrenucci Power vs. Thrust, Isp

11. Slide 2.11 Introduction ESA/ESTEC, Noordwijk, September 15-19, 2008 Advanced Course: Electric Propulsion Concepts and Systems M. Andrenucci Power vs. Thrust, Isp

12. Slide 2.12 Introduction ESA/ESTEC, Noordwijk, September 15-19, 2008 Advanced Course: Electric Propulsion Concepts and Systems M. Andrenucci Thrust vs Isp,  T, for given Power Level

13. Slide 2.13 Introduction ESA/ESTEC, Noordwijk, September 15-19, 2008 Advanced Course: Electric Propulsion Concepts and Systems M. Andrenucci Thrust vs Isp,  T, for given Power Level