The AQUAJET propulsion system is currently under investigation and development within Surrey Space Centre, at the University of Surrey, in a collaboration with
AVS UK Ltd., STFC, and SSTL, to address the growing market need for low-cost, low-power propulsion for small communication satellites and constellations. The propulsion system is based on electron cyclotron resonance (ECR) heating using a microwave frequency of 2.45 GHz, and employing a single hollow cylindrical permanent magnet, to produce a magnetic nozzle and ambipolar acceleration. Due to its cathodeless design, the propulsion system is suitable for use with a wide range of alternative propellants, allowing the market to move away from high-cost and low-abundance xenon. The proof-of-concept thruster prototype has a flexible modular design allowing for testing of multiple geometric configurations. Experimental validation of the AQUAJET thruster has been successfully implemented with argon, xenon, and water. Direct thrust measurements have been obtained, using a pendulumtype thrust balance, while operating at load power levels between 17-171 W with multiple propellants at a range of mass flow rates. AQUAJET has demonstrated thrust, and specific impulse of up to: 0.72 mN, 736 s at 171 W (load power) with argon; 0.83 mN, 861 s at 143 W (load power) with xenon; and 0.26 mN, 188 s at 82 W (load power) with water.