Advancing green propulsion: Experimental analysis of dual-mode operation in a hydrogen peroxide monopropellant thruster

Hydrogen peroxide (HTP) is receiving renewed attention as a green monopropellant for small-satellite propulsion. This study presents the design and experimental evaluation of a hydrogen peroxide monopropellant thruster capable of operating in both steady-state and pulsed modes. A modular catalyst bed using silver screens was developed and instrumented to examine decomposition behavior at an HTP concentration of 87.5 wt%. The thruster was tested across a range of operating conditions to assess temperature evolution, pressure stability, and characteristic velocity performance. The results show consistent decomposition, stable operation in both modes, and characteristic velocity efficiencies close to theoretical predictions. Measured temperature profiles enabled the estimation of the decomposition zone, and an uncertainty analysis was conducted to quantify the reliability of the performance metrics. The findings demonstrate that dual-mode operation with silver-based catalysts is feasible within the tested duration and operating range, providing a validated basis for subsequent flight-model development.