A study of 50% liquid H2O2 decomposition on a silver catalyst for CubeSat applications

At present, microsatellites or CubeSats are widely used for various purposes including Earth observation, spacecraft technology demonstration, and scientific experiments. In general, CubeSat orbital time can be extended with an integrated micro-thruster. However, a CubeSat is too small to fit a conventional thruster. Therefore, a small-scale monopropellant thruster has been developed to extend the CubeSat orbital time. With the concept of a monopropellant thruster, 50% W/W hydrogen peroxide (H₂O₂) was used as a propellant, and silver pellets were used as a catalyst. Hydrogen peroxide was initially stored in a pressurized stainless-steel tank and the flow rate was controlled by adjusting the pulse per minute of the solenoid valve to flow the hydrogen peroxide through the catalyst chamber at up to 1.25 mL/min. Type K thermocouples are placed at the exhaust and at the center of the chamber, which is filled with 1.7-mm mean-diameter silver pellets, to measure the temperature from the reaction. Temperature data were recorded using a NI-cDAQ during testing. The decomposition of H₂O₂ and silver catalyst produced water (H₂O), oxygen (O₂), and a significant amount of heat. It was found from the experiment that the activation energy of H₂O₂ decomposition was 36.59 kJ/mol and the pre-exponential factor was 13.3×10⁸ 1/s. This study demonstrated a method to estimate reaction rate constants of H₂O₂ which will benefit the further development of micro-thrusters for CubeSat applications. The use of a small-scale monopropellant thruster can extend the CubeSat orbital time and facilitate various scientific experiments and observations. It is exciting to see the advancements in CubeSat technology and the potential benefits it can bring to space exploration and research.