Monopropellant - Uses

Uses

The most common use of monopropellants is in low-impulse rocket motors, such as reaction control thrusters, the usual propellant being hydrazine which is generally decomposed by exposure to an iridium catalyst bed (Hydrazine is pre-heated to keep reactant liquid) to produce the desired jet of hot gas and thus thrust. Hydrogen peroxide has been used for main thrusters and as power source for propellant tank pumps in rockets like the German WWII V-2 (same as US Redstone rocket). The hydrogen peroxide is passed through a platinum catalyst mesh, or comes in contact with manganese dioxide impregnated ceramic beads, or Z-Stoff permanganate solution is co-injected, which causes hydrogen peroxide to decompose into hot steam and oxygen.

Monopropellants are also used in some air-independent propulsion systems (AIP) to "fuel" reciprocating or turbine engines in environments where free oxygen is unavailable. Weapons intended primarily for combat between nuclear powered submarines generally fall into this category. The most commonly used propellant in this case is stabilized propylene glycol dinitrate (PGDN), often referred to as "Otto fuel". A potential future use for monopropellants not directly related to propulsion is in compact, high-intensity powerplants for aquatic or exoatmosperic environments.