Editing Hypergolic propellant (section)

== Hypergolic combinations ==

=== Common ===
Common hypergolic propellant combinations include:<ref>{{cite web |url=http://www.braeunig.us/space/propel.htm |title=ROCKET PROPELLANTS |website=braeunig.us}}</ref>
* [[Aerozine 50]] + [[nitrogen tetroxide]] (NTO) is widely used in historical American rockets, including the Titan II and all engines in the [[Apollo Lunar Module]]. Aerozine 50 is a mixture of 50% UDMH and 50% straight hydrazine (N<sub>2</sub>H<sub>4</sub>).<ref name="Ignition"/>{{rp|45}}
* Monomethylhydrazine (MMH) + NTO is used in smaller engines and reaction control thrusters: [[Apollo command and service module]] [[Reaction_control_system|RCS]],<ref>{{cite book
 |date=December 1971
 |title=Apollo 11 Mission Report - Performance of the Command and Service Module Reaction Control System
 |url=https://ntrs.nasa.gov/api/citations/19720017210/downloads/19720017210.pdf
 |archive-url=https://web.archive.org/web/20220712145711/https://ntrs.nasa.gov/api/citations/19720017210/downloads/19720017210.pdf
 |archive-date=12 July 2022
 |publisher=NASA - Lyndon B. Johnson Space Center
 |pages= 4,8
}}</ref> Space Shuttle [[Orbital Maneuvering System|OMS]] and [[Reaction_control_system|RCS]];<ref>{{cite book
 |last=T.A.
 |first=Heppenheimer
 |date=2002
 |title=''Development of the Shuttle, 1972–1981 - Volume 2.''
 |url=https://books.google.com/books?id=LqhqBgAAQBAJ
 |publisher=Smithsonian Institution Press
 |page= <!-- or pages= -->
 |isbn=1-58834-009-0
}}</ref> [[Ariane 5]] EPS;<ref>{{cite web | url =http://www.spacelaunchreport.com/ariane5.html#config | archive-url =https://archive.today/20130202175747/http://www.spacelaunchreport.com/ariane5.html#config | url-status =usurped | archive-date =February 2, 2013 | title=Space Launch Report: Ariane 5 Data Sheet}}</ref> [[Draco (rocket engine)|Draco]] thrusters used by the [[SpaceX Dragon]] spacecraft.<ref name=sxu20071210>{{cite web|url=http://www.spacex.com/updates_archive.php?page=121007 |title=SpaceX Updates|publisher=[[SpaceX]] |date=2007-12-10 |access-date=2010-02-03 |url-status=dead |archive-url=https://web.archive.org/web/20110104061453/http://www.spacex.com/updates_archive.php?page=121007 |archive-date=January 4, 2011 }}</ref>
* [[Triethylborane]]/[[triethylaluminium]] (TEA-TEB) + [[liquid oxygen]] is used during the ignition process of some rocket engines that use liquid oxygen, used by the [[Merlin (rocket engine family)|SpaceX Merlin Engine Family]] and [[Rocketdyne F-1]].
* UDMH + NTO is frequently used by [[Roscosmos]], such as in the [[Proton (rocket family)]], and supplied by them to France for the Ariane 1 first and second stages (replaced with [[UH 25]]) and [[Indian Space Research Organisation|ISRO]] rockets using [[Vikas (rocket engine)|Vikas engine]].<ref>{{Cite web|url=http://www.hindu.com/2001/12/03/stories/2001120300481300.htm|archive-url=https://web.archive.org/web/20140323164318/http://www.hindu.com/2001/12/03/stories/2001120300481300.htm|url-status=dead|archive-date=2014-03-23|title=ISRO tests Vikas engine|date=2014-03-23|work=[[The Hindu]]|access-date=2019-07-29}}</ref>

=== Less common or obsolete ===

Less-common or obsolete hypergolic propellants include:
* Aniline + nitric acid (unstable, explosive) is used in the [[WAC Corporal]].<ref>{{cite web
|url=https://airandspace.si.edu/collection-objects/rocket-liquid-fuel-sounding-wac-corporal/nasm_A19590009000
|title=WAC Corporal Sounding Rocket
|url-status=live
|archive-url=https://web.archive.org/web/20220107072025/https://airandspace.si.edu/collection-objects/rocket-liquid-fuel-sounding-wac-corporal/nasm_A19590009000
|archive-date=7 January 2022}}</ref> 
* Aniline + hydrogen peroxide (dust-sensitive, explosive)
* [[Furfuryl alcohol]] + [[red fuming nitric acid]] – [[Copenhagen Suborbitals]] SPECTRA Engine<ref>{{cite web |title=Project SPECTRA - Experimental evaluation of a Liquid storable propellant |url=http://copenhagensuborbitals.com/public/spectra.pdf |archive-url=https://web.archive.org/web/20131104140052/http://copenhagensuborbitals.com/public/spectra.pdf |archive-date=4 November 2013 |url-status=dead}}</ref><ref name="Ignition"/>{{rp|27}}
* Furfuryl alcohol + [[Nitric_acid#Anhydrous_nitric_acid|white fuming nitric acid]]<ref name="Ignition"/>{{rp|27}}
* Hydrazine + nitric acid (toxic but stable) was abandoned due to lack of reliable ignition. No engine with this combination ever went into mass production.<ref>{{cite web|title=Nitric acid/Hydrazine|url=http://www.astronautix.com/n/nitricacidhydrazine.html|publisher=Astronautix.com|access-date=January 13, 2023}}</ref>
* Kerosene + (high-test peroxide + catalyst) is used in [[Gamma (Rocket engine)|Gamma]], with the peroxide first decomposed by a catalyst. Cold hydrogen peroxide and kerosene are not hypergolic, but concentrated hydrogen peroxide (referred to as high-test peroxide or HTP) run over a catalyst produces free oxygen and steam at over {{Convert|700|C|F|-2}}, which is hypergolic with kerosene.<ref>{{Cite web|url = http://forum.nasaspaceflight.com/index.php?action=dlattach;topic=31490.0;attach=519423|title = High Test Peroxide|access-date = July 11, 2014|format = pdf}}</ref>
*[[Tonka (fuel)|Tonka]] (TG-02, about 50% [[triethylamine]] and 50% [[xylidine]]) typically oxidized with nitric acid or its anhydrous nitric oxide derivatives (AK-2x group in the Soviet Union) e.g. [[red fuming nitric acid|AK-20F]] (80% HNO<sub>3</sub> and 20% N<sub>2</sub>O<sub>4</sub> with [[Reaction inhibitor|inhibitor]]).<ref name="Ignition"/>{{rp|14-15,116}}
* ''[[T-Stoff]]'' (stabilized >80% peroxide) + ''[[C-Stoff]]'' (methanol, hydrazine, water, catalyst) was used in [[Messerschmitt Me 163]] World War II German rocket fighter aircraft, for its [[Walter HWK 109-509|Walter 109-509A]] engine.<ref name="Ignition"/>{{rp|13}}
* Turpentine + red fuming nitric acid (flown in French Diamant A first-stage)<ref>{{cite web
|url=http://www.b14643.de/Spacerockets/Specials/European_Rocket_engines/engines.htm
|title=European space-rocket liquid-propellant engines
|url-status=live
|archive-url=https://web.archive.org/web/20210723223834/https://b14643.de/Spacerockets/Specials/European_Rocket_engines/engines.htm
|archive-date=23 July 2021}}</ref>
* UDMH + red fuming nitric acid is used in the [[MGM-52 Lance]] missile system,<ref>{{cite web
|url=http://www.astronautix.com/p/p8e-9.html
|title=P8E-9
|url-status=live
|archive-url=https://web.archive.org/web/20220512200958/http://www.astronautix.com/p/p8e-9.html
|archive-date=12 May 2022}}</ref> [[RM-81_Agena|Agena]] and [[Able_(rocket_stage)|Able]] Upper Stages, and Isayev-built maneuvering engines.<ref>{{cite web
|url=http://www.astronautix.com/n/nitricacidudmh.html
|title=Nitric Acid/UDMH
|url-status=live
|archive-url=https://web.archive.org/web/20220701200932/http://astronautix.com/n/nitricacidudmh.html
|archive-date=1 July 2022}}</ref>

=== Proposed, remain unflown ===

* [[Chlorine trifluoride]] (ClF<sub>3</sub>) + all known fuels – Briefly considered as an oxidizer given its high hypergolicity with all standard fuels, it was ultimately abandoned in the 1970s due to the difficulty of handling the substance safely. ClF<sub>3</sub> is known to burn concrete and gravel.<ref name="Ignition">{{Cite book | last = Clark | first = John D. | author-link = John Drury Clark | title = Ignition! An Informal History of Liquid Rocket Propellants | publisher = Rutgers University Press | year = 1972 | isbn = 978-0-8135-0725-5 |url = https://library.sciencemadness.org/library/books/ignition.pdf | url-status=live | archive-url=https://web.archive.org/web/20220710061023/https://library.sciencemadness.org/library/books/ignition.pdf |archive-date=10 July 2022}}</ref>{{rp|74}} [[Chlorine pentafluoride]] (ClF<sub>5</sub>) presents the same hazards, but offers higher [[specific impulse]] than ClF<sub>3</sub>.
* [[Pentaborane(9)]] and diborane + nitrogen tetroxide – Pentaborane(9), a so-called [[zip fuel]], was studied by Soviet rocket scientist [[Valentin_Glushko|V. P. Glushko]] for use in combination with nitrogen tetroxide in the [[RD-270|RD-270M]] rocket engine. This propellant combination would have yielded a significant increase in performance, but was ultimately given up due to toxicity concerns.<ref name=L1>[http://www.astronautix.com/engines/rd270.htm Astronautix: '''RD-270'''] {{webarchive|url=https://web.archive.org/web/20090430234903/http://astronautix.com/engines/rd270.htm |date=2009-04-30 }}.</ref>
* [[Tetramethylethylenediamine]] +red fuming nitric acid is a sightly less-toxic alternative to hydrazine and its derivatives.