The thrust generated by a T6 ion engine hollow cathode

•The paper deals with the use of a hollow cathode (HC) as a stand-alone thruster.•First data ever for the thrust from a HC working with xenon, argon and krypton.•Thrust production mechanism is closer to that of an arcjet than of a resistojet.•Isp exceeds what could be achieved from a flow in thermal equilibrium with the wall.

The thrust produced by a T6 ion engine main discharge hollow cathode was characterized using different propellants with a target-based measurement system, for discharge current values of 5–25 A and a wide range of mass flow rates. The calculated values of specific impulse are far in excess of those that could be attributed to the heating of a gas to thermal equilibrium with the walls, as in a resistojet. This would suggest an operation mechanism more similar to that of an arcjet. The main scaling parameter for the specific impulse appears to be the discharge power per unit mass flow rate (specific power).