Improvement on Stability of Water Arcjet

An electric thruster using water propellant has enormous potential for human spaceflight missions. Seriously unstable mechanisms of a previous water arcjet are analyzed. The experiment simulating the vaporization of water shows the fluctuations of the plume and the arc voltage mainly result from the vaporization process in the supply pipe. A new supply pipe including capillary bundles and a buffer is developed, and the principle of stable vaporization in the capillary bundles is presented. By using this set of system, relatively stable vaporization of water in pipes is achieved. Performance research is carried out in a new designed thruster using water as a propellant. The experiment results prove that the stability of water arcjet is improved. Specific impulse and efficiency reach 530-580 s and 40%-50%, respectively, at a water flow rate of 20-30 mg/s and a power of 500-700 W.