Search results
Results from the WOW.Com Content Network
This low thrust makes ion thrusters unsuited for launching spacecraft into orbit, but effective for in-space propulsion over longer periods of time. Ion thrusters are categorized as either electrostatic or electromagnetic. The main difference is the method for accelerating the ions.
Although the engine produces just 92 millinewtons (0.331 ounce-force) thrust at maximum power (2,100W on DS1 mission), the craft achieved high speed because ion engines thrust continuously for long periods of time. [7] "The 30-cm ion thruster operates over a 0.5 kW to 2.3 kW input power range providing thrust from 19 mN to 92 mN.
An ion-propelled aircraft or ionocraft is an aircraft that uses electrohydrodynamics (EHD) to provide lift or thrust in the air without requiring combustion or moving parts. Current designs do not produce sufficient thrust for crewed flight or useful loads.
The use of ion propulsion systems were first demonstrated in space by the NASA Lewis Space Electric Rocket Test (SERT) I and II. [2] These thrusters used mercury as the reaction mass. The first was SERT-1 , launched July 20, 1964, which successfully proved that the technology operated as predicted in space.
6 kW Hall thruster in operation at the NASA Jet Propulsion Laboratory. In spacecraft propulsion, a Hall-effect thruster (HET) is a type of ion thruster in which the propellant is accelerated by an electric field. Hall-effect thrusters (based on the discovery by Edwin Hall) are sometimes referred to as Hall thrusters or Hall-current thrusters.
The NEXT thruster has demonstrated, in ground tests, a total impulse of 17 MN·s; which as of 2010 was the highest total impulse ever demonstrated by an ion thruster. [2] A beam extraction area 1.6 times that of NSTAR allows higher thruster input power while maintaining low voltages and ion current densities, thus maintaining thruster longevity.
A variety of other rocket propulsion methods, such as ion thrusters, give much higher specific impulse but with much lower thrust; for example the Hall-effect thruster on the SMART-1 satellite has a specific impulse of 1,640 s (16.1 km/s) but a maximum thrust of only 68 mN (0.015 lbf). [45]
A 4-grid ion thruster with only 0.2 m diameter is projected to absorb 250 kW power. With that energy input rate, the thruster could produce a thrust of 2.5 N . The specific impulse (a measure of fuel efficiency ), could reach 19,300 s at an exhaust velocity of 210 km/s if xenon propellant was used. [ 3 ]