The "Greening" of Spacecraft Reaction Control Systems

Recently, higher performance (i.e., reduction of propellant consumption), operability improvement/safer handling (i.e., lower toxicity) and cost reduction are required for thrusters used for the orbital maneuvering and attitude control of spacecraft such as rockets, artificial satellites and space probes. For this reason, reaction control systems (RCSs) which use lower toxicity propellants called “Green Propellants” instead of the conventional toxic propellant hydrazine are attracting attention as next generation fuels. Mitsubishi Heavy Industries, Ltd. (MHI) has continued the development of monopropellant thrusters that use SHP, a green hydroxylammonium nitrate (HAN)-based propellant that has the potential to achieve higher performance than hydrazine. This report describes the results of the evaluation of system advantages and safety (detonability), as well as the firing test for evaluating lifetime.