State of the art of radio-frequency ion sources for space propulsiona)

Abstract

After 30 years of research, development, and qualification work of radio-frequency ion thrusters (RIT), the RIT 10 engine has now been tested successfully in space onboard the European Retrievable Carrier (EURECA). RIT 10 produces a thrust of 10 mN and is designed for north–south stationkeeping of geosynchronous satellites. Besides, the European Space Agency (ESA/ESTEC) plans to implement ion propulsion in their technological satellite ARTEMIS, where ion thrusters shall be used operationally for north–south stationkeeping. In parallel, development and tests of a scaled-up 50 mN engine RIT 15 have been continued successfully with xenon and krypton as propellants. A large ion engine with a 35 cm ionizer diameter, the RIT 35, has been developed for primary propulsion of interplanetary probes aiming at a thrust level in the 250 mN range. A laboratory prototype has been subjected to extensive testing and performance mapping. Recently, this work has been continued in European cooperation due to a redirection of contracts. The ion source diameter has been reduced to 26 cm but the performance should be kept using a British high perveance grid at the German rf-ion source.

Electric propulsion for satellites and spacecraft: established technologies and novel approaches

“…Many detailed articles about the physics, the limitations and applications of ion engines have been published; see e.g. references [3,5,6,[58][59][60][61]. Here, we only propose an overview of the working principles with emphasis on ion production methods and thrust generation.…”

“…Ionization can be achieved by means of waves as well. An external inductive coil wound around the thruster body can inductively couple a radiofrequency (RF) wave to the plasma [60][61][62][63][64][65][66]. The energy is then deposited close to the dielectric walls in a narrow region of the size of the electron skin depth where an evanescent electric field exists.…”

Thrust evaluation of compact ECR plasma source using 2-zone global model and plasma measurements

“…been described along with development trends, different ight programs, etc. Leading thruster technologies like the ion [8,9], Hall-effect [10,11] and high ef ciency multistage plasma [3] thrusters are all plasma based, where a propellant gas is ionized and only the positive ions are accelerated either using biased electrodes (for ion thruster) or by creating a crossed eld (Hall and multistage plasma thruster). However, electrons also need to be ejected from the system to avoid charging of the vessel since this would impede out ow of ions and lead to eventual failure of the device.…”

Magnetically Enhanced Inductive Source for Electric Propulsion Applications

“…R ADIO frequency driven plasma sources have seen success in electric propulsion applications as embodied in the RIT series of ion thrusters. 1 Recently, a radio frequency ion thruster originally intended for north-south station keeping was used for orbit-raising to salvage a communication satellite (ARTEMIS) accidentally placed in the wrong orbit. 2 Rf-driven plasma production offers many distinct advantages over conventional, DC plasma sources presently being used in electric propulsion devices such as ion and Hall thrusters.…”

“…Conventional rf thruster systems employ the classic inductive discharge configuration. 8 Here an external, rf driven coil wrapped along the outer diameter of a dielectric discharge chamber is used to couple power to the gas to produce and sustain a plasma discharge by transformer action. In this regard, in these "barrel" sources, power is deposited into a skin depth typically on the order of centimeters in spatial extent (collisionless case).…”