Hydrazine is a commonly used aerospace propellant for low to medium thrust applications. However, it is suspected of being carcinogenic and requires additional equipment and safety protocols, which increases the cost of fuel.
Hydrogen peroxide is a much less toxic alternative to hydrazine. It is largely non-toxic to humans and has typical household uses such as bleaching hair or cleaning wounds.
Generating thrust from hydrogen peroxide requires a catalyst. It can be a precious metal, such as silver or platinum.
University of Canterbury engineering student Simon Reid is interested in the intersection of 3D printing and aerospace. Currently, he is working on a 3D-printed catalytic bed that enables more efficient use of concentrated hydrogen peroxide as a propellant for rockets requiring low to medium thrust.
Simon coated the surface of the ceramic catalyst with the catalyst for the hydrogen peroxide to pass through.
Simon explains, “Bypassing liquid hydrogen peroxide over a bed of catalyst speeds up the decomposition reaction. The reaction breaks the molecule apart, turning it into water and oxygen. Breaking the molecule produces a large amount of energy and heat. The heat vaporizes the water and produces a high temperature gas – passing hot gas through a nozzle provides thrust.
Simon aims to maximize thrust generation from hydrogen peroxide. At the same time, he wants to limit catalyst loss from the bed and keep the components lightweight.
Working with Callaghan Innovation, Simon is using 3D printing to generate new catalytic structures that have better properties, such as lower pressure drop, and use different catalytic materials to improve thruster performance.
Simon said, “The shape I use is called a gyroid. It is a mathematical form, more optimal for catalytic processes, and cannot be made using traditional techniques.
By using the gyroid, Simon wants to overcome three things:
- Catalyst loss
- large pressure drop
- Maximized balanced thrust versus hydrogen peroxide concentration.