Monopropellant Monopropellants are propellants consisting of chemicals that do not require an oxidizer to release their stored chemical energy . While stable under defined storage conditions , they decompose very rapidly under certain other conditions to produce a large volume of energetic ( hot ) gases for the performance of mechanical work . Although solid deflagrants such as nitrocellulose , the most commonly used propellant in firearms , and ammonium perchlorate / aluminum / synthetic rubber , widely used in military and spacecraft boosters , could be thought of as monopropellants , the term is usually reserved for liquids in engineering literature . Monopropellants release their energy through exothermic chemical decomposition . The molecular bond energy of the monopellant is released usually through use of a catalyst . This can be contrasted with bipropellants that release energy through the chemical reaction between an oxidizer and a fuel . Uses . The most common use of monopropellants is in low - impulse rocket motor s , 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 and the American Redstone . 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 . Research in brief . Much work was done in the US in the 1950s and 1960s to attempt to find better and more energetic monopropellants . For the most part , researchers came to the conclusion that any single substance that contained enough energy to compete with bipropellants would be too unstable to handle safely under practical conditions . With new materials , control systems and requirements for high - performance thrusters , engineers are currently re - examining this assumption . Many partially nitrated alcohol esters are suitable for use as monopropellants . " Trimethylene glycol dinitrate " or 1 , 3 - propanediol dinitrate is isomer ic with PGDN , and produced as a fractional byproduct in all but the most exacting laboratory conditions ; the marginally lower specific gravity ( and thus energy density ) of this compound argues against its use , but the minor differences in chemistry may prove useful in the future . The related " dinitrodiglycol " , more properly termed diethylene glycol dinitrate in modern notation , was widely used in World War 2 Germany , both alone as a liquid monopropellant and colloidal with nitrocellulose as a solid propellant . The otherwise desirable characteristics of this compound ; it is quite stable , easy to manufacture , and has a very high energy density ; are marred by a high freeze point ( - 11 . 5 deg . C ) and pronounced thermal expansion , both being problematic in spacecraft . " Dinitrochlorohydrin " and " tetranitrodiglycerin " are also likely candidates , though no current use is known . The polynitrates of long chain and aromatic hydrocarbons are invariably room temperature solids , but many are soluble in simple alcohols or ethers in high proportion , and may be useful in this state . Hydrazine , ethylene oxide , hydrogen peroxide , ( especially in its German World War II form as " T - Stoff " ) and nitromethane are common rocket monopropellants . As noted the specific impulse of monopropellants is lower than bipropellants and can be found with the Air Force Chemical Equilibrium Specific Impulse Code tool . Newer monopropellants include nitrous oxide fuel blend s . Nitrous oxide may be blended with a range of different fuels and emulsifiers and used as a rocket monopropellant . Nitrous oxide monopropellants decompose into oxygen - rich air , and they require no separate supply of oxidizer such as the liquid oxygen used in many high performance rocket engines today .