Catalytic Injectors for an Isochoric Hybrid Rocket Motor

The EU H2020 HYPROGEO Project, coordinated by Airbus Defence and Space (Toulouse), called for the design and manufacture of two sets of catalytic injectors for a novel, isochoric hybrid rocket motor. The hybrid motor forms the basis of a propulsion system for future GEO/apogee-kick applications. The motor burns its fuel axially rather than radially and relies on a constant, vortical flow of hot oxygen for ignition and sustained combustion. The hot oxygen is provided by the rapid decomposition of hydrogen peroxide. Two aqueous concentrations were used: 87.5% for an intermediate motor, and 98% for the final breadboard design. Critical to success is the catalyst, referred to as PX1. This comprises a ceramic substrate and an active (catalytic) surface. On contact with hydrogen peroxide, oxygen and steam are liberated exothermically. The efficacy of PX1, used in combination with 98% concentration peroxide, was demonstrated in 2016.