In April 2021 the group led by dr Jacek Kurzyna of the Institute of Plasma Physics and Laser Microfusion completed the High Impulse Krypton Hall Effect Thruster (HIKHET) project (funded by the European Space Agency in the scope of Polish Industry Incentive Scheme programme), which was aimed to develop a high specific impulse version of the IPPLM’s 500 W class Hall plasma thruster operated with krypton propellant.

Hall thruster fed with krypton and working in PlaNS Laboratory

Specific impulse, i.e. the impulse per one kilogram of the propellant, is a measure of how effectively the propellant available onboard of a satellite is utilized. Since almost all of the new satellites are equipped with a propulsion system which allows them to carry out orbital maneuvers to extend their mission and to finally deorbit, it is the amount of available propellant onboard which largely determines the lifetime of the satellite.

During the 3 years of the project, in the Plasma Nudge for Satellites (PlaNS) Laboratory the initial version of the thruster (developed in the scope of the earlier KLIMT project) was enhanced and extensively tested, new diagnostics of the emitted plasma beam were implemented (Faraday Cup and Retarding Potential Analyzer), and an entirely new thruster was designed relying on the results from magnetic field modelling and thermal simulations. The final version of the thruster was tested in a wide range of operating parameters (type of propellant, mass flow rate, discharge voltage, magnetic field strength), showing an increase of the specific impulse from 1400 s to 2600 s and simultaneous efficiency improvement from 20% to 34% (for krypton). Moreover, the new design resulted in operating temperature lower by 100^oC and mass reduced by 30%. The achieved performance allows to compete with other Hall thruster of similar power, and makes the IPPLM’s thruster unique in the way of specific impulse production.

Specific impulse as a function of discharge power – comparison of KLIMT and HIKHET thrusters with other Hall thrusters described in literature (data for krypton)

Figures: © IPPLM