Editing Monopropellant rocket (section)

== History ==
[[File:Lunar Landing Research Vehicle No. 2 in 1967 (ECN-1606) retouched.jpg|thumb|Lunar Landing Research Vehicle with 18 Hydrogen Peroxide Monopropellant Thrusters]]
Soviet designers had begun experimenting with monopropellant rockets as early as 1933.<ref name=":0" /> They believed their monopropellant mixes of [[Dinitrogen tetroxide|nitrogen tetroxide]] with gasoline, or toluene, and kerosene would lead to an overall simpler system; however, they ran into problems with violent explosions with pre-mixed fuel and oxidizer serving as a monopropellant that led the designers to abandon this approach.<ref name=":0">{{Cite book |last=Sutton |first=George |title=History of Liquid Propellant Rocket Engines |publisher=American Institute of Aeronautics and Astronautics |year=2006 |isbn=1563476495 |location=Reston, Virginia |pages=533–534}}</ref>

[[Hellmuth Walter|Helmuth Walter]] was a German engineer an early pioneer of monopropellant rockets using hydrogen peroxide as fuel.<ref name=":02">{{Cite web |last=Stokes |first=P. R. |date=14 January 1998 |title=Hydrogen Peroxide for Power and Propulsion |url=http://www.cue-dih.co.uk/aerospace/aeropdfs/htp_for_prop.pdf |url-status=dead |archive-url=https://web.archive.org/web/20060215104117/http://www.cue-dih.co.uk/aerospace/aeropdfs/htp_for_prop.pdf |archive-date=15 February 2006 |access-date=24 January 2024}}</ref> Although his initial work was on submarine propulsion the same jets of oxygen produced by for combustion in gas turbines could be directed through a nozzle to generate thrust.<ref name=":02" /> The rocket Walter developed was used in the German [[Messerschmitt Me 163 Komet|ME-163]] fighter aircraft in 1944, the first aircraft to break the 1000 km/h (635 mph).<ref name=":02" />  

After World War Two the British would continue to experiment with hydrogen peroxide monopropellants.<ref name=":02" /> They would develop the [[de Havilland Sprite]] a hydrogen peroxide rocket that could produce 5000lbf of thrust over 16 seconds. Not intended for space flight the rocket would provide hot and high takeoff capability to the [[De Havilland Comet|de Havilland Comet 1]] the first commercial jet airliner.<ref name=":02" /> 

In the United States, when NASA began studying monopropellants at the Jet Propulsion Laboratory (JPL) the properties of the existing propellants demanded that the thrusters be impractically large.<ref name=":1" /> The addition of a catalyst and pre-heating propellant made them more efficient, but raised concerns over safety and handling of hazardous propellants like anhydrous [[hydrazine]].<ref name=":1">{{Cite web |last1=Price |first1=T.W. |last2=Evans |first2=D. D. |date=February 15, 1968 |title=The Status of Monopropellant Hydrazine Technologies |url=https://ntrs.nasa.gov/api/citations/19680006875/downloads/19680006875.pdf |access-date=March 21, 2024 |series=TR 32-1227 |publisher=National Aeronautics and Space Administration |pages=1–2}}</ref> However the simplicity of the thrusters designed around early monopropellants offered many simplicities and were first tested in 1959 on the [[Pioneer P-3|Able-4]] mission.<ref name=":12" /> This test allowed for the [[Ranger program|Ranger]] and [[Mariner program|Mariner]] missions to use a similar thruster for correction maneuvers<ref name=":12">{{Cite web |last1=Price |first1=T.W. |last2=Evans |first2=D. D. |date=February 15, 1968 |title=The Status of Monopropellant Hydrazine Technologies |url=https://ntrs.nasa.gov/api/citations/19680006875/downloads/19680006875.pdf |access-date=March 21, 2024 |series=TR 32-1227 |publisher=National Aeronautics and Space Administration |pages=1–2}}</ref> and in the orbital insertion of [[Telstar]], considered by the National Air and Space Museum to be the most significant communications satellite in the beginning of the space race.<ref>{{Cite web |title=Telstar |url=https://airandspace.si.edu/collection-objects/communications-satellite-telstar/nasm_A20070113000 |access-date=March 8, 2024 |website=National Air and Space Museum}}</ref>
[[File:Centaur rocket stage.jpg|thumb|Centaur III Upper Stage with 12 Hydrazine Monopropellant Thrusters]]
In 1964, NASA began use of the [[Lunar Landing Research Vehicle]] to train Apollo astronauts in piloting the [[Apollo Lunar Module|Lunar Excursion Module]] (LEM) using an attitude control system consisting of 16 hydrogen peroxide monopropellant thrusters to steer the LEM to the lunar surface.<ref>{{Cite web |date=October 30, 2019 |title=55 Years Ago: The First Flight of the Lunar Landing Research Vehicle |url=https://www.nasa.gov/history/55-years-ago-the-first-flight-of-the-lunar-landing-research-vehicle/ |access-date=March 8, 2024 |website=National Aeronautics and Space Administration}}</ref>

Upper stage vehicles began using monopropellant thrusters as a convenient control device in the early 1960s when General Dynamics proposed the Centaur upper stage to the United States Airforce<ref>{{Cite web |last=Arrighi |first=Robert |title=Centaur: America's Workhorse in Space |url=https://www.nasa.gov/history/centaur-americas-workhorse-in-space/ |access-date=April 19, 2024 |publisher=National Aeronautics and Space Administration |publication-date=December 12, 2012}}</ref> of which versions are still in use in [[United Launch Alliance]]'s [[Atlas-Centaur|Atlas]] and [[Vulcan Centaur|Vulcan]] rockets.<ref>{{Cite web |year=2010 |title=Atlas V Users Guide |url=https://www.ulalaunch.com/docs/default-source/rockets/atlasvusersguide2010a.pdf?sfvrsn=f84bb59e_2 |access-date=April 19, 2024 |publisher=United Launch Alliance}}</ref>