7. What is the highest efficiency demonstrated by the VASIMR® engine?
At the International Electric Propulsion Conference (IEPC) in September 2011, Ad Astra presented VX-200 testing results that demonstrate a system efficiency (fraction of the jet power to the input DC power) of 60% . The thruster efficiency, which is the the fraction of the jet power to the RF input power, was measured to be 72%. Both efficiencies were measured at a power of 210 kW and a specific impulse (Isp) of 4800 seconds using argon propellant.