Editing Propellant (section)

====Liquid propellant====
{{Further|liquid fuel|liquid-propellant rocket}}
In rockets, three main liquid bipropellant combinations are used:  cryogenic oxygen and hydrogen, cryogenic oxygen and a hydrocarbon, and storable propellants.<ref name=sutton2001>
{{cite book |last=Sutton|first=George |author2=Biblarz, Oscar  |title=Rocket Propulsion Elements |year=2001 |publisher=Willey |isbn=9781601190604 |oclc=75193234 }}</ref>
; [[Cryogenic]] [[liquid oxygen|oxygen]]-[[liquid hydrogen|hydrogen]] combination system: Used in upper stages and sometimes in booster stages of space launch systems. This is a nontoxic combination. This gives high [[specific impulse]] and is ideal for high-velocity missions.
; Cryogenic oxygen-hydrocarbon propellant system: Used for many booster stages of space [[launch vehicle]]s as well as a smaller number of [[second stage]]s. This combination of fuel/oxidizer has high density and hence allows for a more compact booster design.
; Storable propellant combinations: Used in almost all bipropellant low-thrust, auxiliary or [[reaction control system|reaction control]] rocket engines, as well as in some in large rocket engines for first and second stages of ballistic missiles. They are instant-starting and suitable for long-term storage.

Propellant combinations used for [[bipropellant rocket|liquid propellant rocket]]s include:
* [[Liquid oxygen]] and [[liquid hydrogen]]<ref name=ars20130414a>
{{cite news|last=Hutchinson|first=Lee |title=New F-1B rocket engine upgrades Apollo-era design with 1.8 M lbs of thrust |url=https://arstechnica.com/science/2013/04/new-f-1b-rocket-engine-upgrades-apollo-era-deisgn-with-1-8m-lbs-of-thrust/ |access-date=2013-04-15 |newspaper=ARS technica |date=2013-04-14 |quote=''The most efficient fuel and oxidizer combination commonly used today for chemical liquid rockets is hydrogen (fuel) and oxygen (oxidizer)," continued Coates. The two elements are relatively simple and they burn easily when combined—and even better, the result of their reaction is simple water.''}}</ref>
* [[Liquid oxygen]] and [[kerosene]] or [[RP-1]]<ref name=ars20130414b>
{{cite news|last=Hutchinson|first=Lee |title=New F-1B rocket engine upgrades Apollo-era design with 1.8 M lbs of thrust |url=https://arstechnica.com/science/2013/04/new-f-1b-rocket-engine-upgrades-apollo-era-deisgn-with-1-8m-lbs-of-thrust/2/ |page=2 |access-date=2013-04-15 |newspaper=ARS technica |date=2013-04-14 |quote=''Refined petroleum is not the most efficient thrust-producing fuel for rockets, but what it lacks in thrust production it makes up for in density. It takes less volume of RP-1 to impart the same thrust force on a vehicle, and less volume equates to reduced stage size. ... A smaller booster stage means much less aerodynamic drag as the vehicle lifts off from near sea-level and accelerates up through the more dense (thicker) part of the atmosphere near the earth. The result of a smaller booster stage is it allows a more efficient ascent through the thickest part of the atmosphere, which helps improve the net mass lifted to orbit.''}}</ref>
* [[Liquid oxygen]] and [[ethanol]]
* Liquid oxygen and [[methane]]
* [[High-test peroxide|Hydrogen peroxide]] and mentioned above alcohol or [[RP-1]]
* [[Red fuming nitric acid]] (RFNA) and [[kerosene]] or [[RP-1]]
* RFNA and [[Unsymmetrical dimethylhydrazine]] (UDMH)
* [[Dinitrogen tetroxide]] and UDMH, [[monomethylhydrazine|MMH]], and/or [[hydrazine]]

Common monopropellant used for [[liquid-propellant rocket|liquid rocket engines]] include:
* Hydrogen peroxide
* [[Hydrazine]]
* Red fuming nitric acid (RFNA)