UK Space Agency Funding Development of Aquajet Space Thruster

The Aquajet thruster uses accelerates water ions for propulsion. Credit: AVS.

The UK Space Agency has a new plasma thruster in development, called Aquajet. It joins other water-based thrusters covered previously such as Bradford Space’s Comet, Tethers Unlimited’s HYDROS, and Momentus’ Vigor. Aquajet will utilize electrical current to positively charge and accelerate water ions which are then expelled from the thruster chamber at high velocity to generate thrust.

Diagram of how the Aquajet works. Credit: STFC.

The current standard of Hall-effect thrusters require high voltages to maintain thrust and heavy storage tanks to keep the propellant under pressure, resulting in higher mass and system complexity. As a plasma thruster, Aquajet is designed to be electrode-less, which reduces system mass and complexity at the expense of exhaust velocity. This beneficial trade-off allows Aquajet to keep performance erosion at a minimum while utilizing a variety of fuels such as water, xenon, argon, CO2, NH3, etc.

This development effort is supported by a €560,000 grant, and is aimed at producing effective and environment-friendly propellants. The outstanding benefit of thrusters using this technology is also the potential for reuse via refueling. Thrusters of this type become a viable customer for water extracted on the Moon or asteroids. Launching any amount of mass, including water, into space from Earth’s surface involves a costly usage of rocket propellant at minimum. Sources for water and other materials in space are valuable opportunities for significant cost savings.