Ion Propulsion - Transport System t' t' Planets T' efficiency o' a rocket engine can be described by its specific impulse, ya bilge rat, which be t' change o' momentum gained from a 1 kilogram weight o' propellent. T' Space Shuttle main engines have a specific impulse o' 453 seconds which is typical o' a liquid fuelled rocket engine. An Ion thruster has a specific impulse o' more than 3000 seconds and so requires less than a sixth o' t' fuel o' a liquid fuelled engine. Blimey! Gridded electrostatic ion thrusters commonly utilize Xenon gas. T' gas is first ionized by bombardin' it with electrons. T' positively charged ions then diffuse through t' positive grid and enter a potential difference betwixt t' positive and negative grids. T' potential difference accelerates t' ions t' high velocities, which then leave t' engine t' create thrust. An electron emitter, on t' exterior o' t' engine, shiver me timbers, neutralizes t' ion beam t' prevent charge build-up. T' typical thrust o' an ion engine is equivalent t' a weight o' 10 grams - about t' weight o' a sheet o' paper. Ya scallywag! This means ion thrusters need t' provide continuous thrust for a very long time in order t' achieve a reasonable change in velocity. Blimey! Electrostatic ion engines have been tested for 3.5 years o' continuous thrust at full power. Begad! Collision o' ions with t' charged grids causes their erosion and will lead t' eventual failure. Ya scallywag! Ion engines consume more than 2 kilowatts o' electrical power, which may be generated by solar arrays or nuclear ...