Performance of propellant for ultrasonically aided electric propulsion

•Description of the UAEP system operation principle.•Experimental study of the effect of propellant properties on UAEP system.•Discussion on the effect of propellant properties on UAEP system.•Choice of the propellant for UAEP system: LiCl/tributyl phosphate.

Ultrasonically aided electric propulsion (UAEP) is a new type of colloid thruster which uses ultrasonic nozzle instead of the traditional capillary or needle emitter. This paper focuses on the effects of propellant upon the performance of UAEP system. Multiple solutions, such as doped formamide, water and tributyl-phosphate were employed and tested as the propellant. The relationships between the spray current and several characteristic parameters of the propellant, such as surface tension coefficient, electrical conductivity, viscosity and doped solute, were experimentally investigated. The experimental results showed that the operation state of UAEP system was greatly influenced by the physical properties of the propellant. The solution of LiCl/tributyl phosphate was selected as the propellant for UAEP.