(2c) Hall Thrusters(with Xenon propellant 1=04-0.6Isp=1500s-1800s→3000(NAsA) P from 0. 5KW to 10KW(can be increased) Isp in very favorable range for many missions(reasonable F/P, good fuel efficiency) Reasonable efficiency Some flight experience(mostly in Russia), more coming on many missions Some concerns on contamination emi, interference Complex PPU (2d) Ion Engines (with Xe propellant) 1≈0.6-0.75Isp=25005-40005→7000(NASA) P from 0. 3KW to 5KW(can be increased) Very good efficien High ISP good for high AV missions Some flight experience(from 1970s), more coming soon(Hughes'XIPs on Galaxy busse Adequate life arge relatively heavy engine (2e) Pulsed Plasma Thrusters(Ppt's with Teflon propellant) 70.05-0.1sp≡1000-1200sec P from o 1 to 1 Kw Very short (us )pulses, widely controllable pulse rate Excellent for precise maneuvering Solid fuel, very simple systems Very low eff Difficulty handling large propellant mass Some flight experience(VELA satellites), more coming (2f) Colloid Engine, Field Emission Electrostatic Propulsion(FEEP Very small unit power(from F N 0.1 HN, P N 0.5 mW) Ideal for high precision missions 500 s to 1500s(colloid Isp from 2000-6000s(colloid in ion-emitting mode 6000s FEEP (liquid metal) Can be multiplexed for mN Thrust. Relatively heavy ancillary components Pro f a spa m artie ssn Lecture 1a 3 of 316.522, Space Propulsion Lecture 1a Prof. Manuel Martinez-Sanchez Page 3 of 3 (2c) Hall Thrusters (with Xenon propellant) η ≅ ≅⇒ 0.4 - 0.6 1500 1800 3000 (NASA) Isp s - s P from 0.5KW to 10KW (can be increased) Isp in very favorable range for many missions (reasonable F/P, good fuel efficiency) Reasonable efficiency Some flight experience (mostly in Russia), more coming on many missions Life adequate Some concerns on contamination, EMI, interference Complex PPU (2d) Ion Engines (with Xe propellant) η ≈ ≅⇒ 0.6 - 0.75 2500 4000 7000 (NASA) Isp s - s P from 0.3KW to 5KW (can be increased) Very good efficiency High ISP good for high ∆V missions Some flight experience (from 1970’s), more coming soon (Hughes’ XIPs on Galaxy busses) Adequate life Very complex PPU Large, relatively heavy engine (2e) Pulsed Plasma Thrusters (PPT’s with Teflon propellant) η ≅ ≅ 0.05 - 0.1 1000 1200sec Isp - P from 0.1 to 1 KW Very short ( µs ) pulses, widely controllable pulse rate Excellent for precise maneuvering Solid fuel, very simple systems Very low efficiency Difficulty handling large propellant mass Some flight experience (VELA satellites), more coming (2f) Colloid Engine, Field Emission Electrostatic Propulsion (FEEP) Very small unit power (fromF ~ 0.1 N, P ~ 0.5 mW µ ) Ideal for high precision missions Isp from 500 s to 1500 s (colloid) 2000 - 6000 s (colloid in ion - emitting mode) 6000 s FEEP (liquid metal) Can be multiplexed for mN Thrust. Relatively heavy ancillary components