List of investigators

Plasma Electrolysis Rocket

Professor John Foster&

Professor Alec Gallimore+

The University of Michigan&Department of Nuclear Engineering and Radiological Sciences

+Department of Aerospace Engineering

Plasma Electrolysis PropulsionBackground and Motivation

•Water electrolysis propulsion — electrochemical decomposition of water into hydrogen and oxygen propellants

•Water electrolysis identified years ago as promising propulsion approach

Higher thrust/power ratio than electric propulsion

Isp >350 s, higher than other storable chemical options

Propellant is environmentally friendly and low cost

Water storage is straightforward

Enables in situ propellant production from water-ice sources on the Moon and Mars

Can be used in conjunction with fuel cells and environmental control systems, respectively

•Previous efforts involved the use of membranes and electrochemical catalysts —limited throughput, increased complexity, and reduced reliability

Plasma Electrolysis Rocket

•Electrolysis can be carried out using high-pressure, non-thermal plasmas

•High-pressure plasma discharge offers distinct advantages over conventional approaches

Increased reliability and higher throughput through the elimination of physical catalystSimplification through the elimination of electrolytesGas production rate depends on discharge power

•Reactivity involves interaction of energetic electrons and radicals with water•Greater control over reactivity•Diffusion of hydrogen and oxygen through water rather than an electrochemical cell also increases throughput

•Reduced system complexity

Background and Motivation

Plasma Electrolysis RocketTechnical Approach and Objectives

• Atmospheric plasma surface discharge test bed experiment Discharge will be characterized as a function of power, excitation

frequency/mode, and electrode geometry Emission spectra will be used to assess production rates Assess hydrogen/oxygen production rates directly via holding cell

pressure measurements and compositional sampling Higher TRL level plasma electrolysis model will be developed

based on experiments– Model will characterize performance– Long-duration test to understand electrode wear and general durability

• Design simple rocket demonstrator

Water plasma approach leverages heritage from ongoing water plasma tests at the Plasma Science and Technology Laboratory and the

Plasmadynamics and Electric Propulsion Laboratory

Plasma Electrolysis RocketAnticipated Results

• Discharge optimization and product characterization– DC operation– Low-frequency RF

• Pulse modulated• Continuous wave

– Sensitivity to water salinity accessed• Completion of experiments aimed

at assessing throughput• Assessment of efficiency and power

requirements relative to conventional electrolysis

• Demonstration of a high-fidelity, laboratory model unit

Schematic Depiction of Test Cell