Editing Hypergolic propellant (section)

{{Short description|Type of rocket engine fuel}}
{{wikt | hypergolic}}
[[File:Hypergolic Fuel for MESSENGER.jpg|thumb|The attendant wears a full [[hazmat suit]] due to the hazards of the hypergolic fuel [[hydrazine]], here being loaded onto the ''[[MESSENGER]]'' space probe]]
A '''hypergolic propellant''' is a [[rocket propellant]] combination used in a [[rocket engine]], whose components [[Spontaneous combustion|spontaneously ignite]] when they come into contact with each other.

The two propellant components usually consist of a [[fuel]] and an [[oxidizer]]. The main advantages of hypergolic propellants are that they can be stored as liquids at room temperature and that engines which are powered by them are easy to ignite reliably and repeatedly. Common hypergolic propellants are extremely [[toxicity|toxic]] or [[corrosiveness|corrosive]], making them difficult to handle.

In contemporary usage, the terms "hypergol" and "hypergolic propellant" usually mean the most common such propellant combination: [[dinitrogen tetroxide]] plus [[hydrazine]].<ref>{{Cite journal |last1=Melof |first1=Brian M. |last2=Grubelich |first2=Mark C. |date=2000-11-15 |title=Investigation of Hypergolic Fuels with Hydrogen Peroxide |url=https://www.osti.gov/biblio/767866 |language=English|journal= 3rd International Hydrogen Peroxide Propulsion Conference|osti=767866 }}</ref>