Editing Rocket engine (section)

==History of rocket engines==
{{main|History of rockets}}
According to the writings of the Roman [[Aulus Gellius]], the earliest known example of [[jet propulsion]] was in c. 400 BC, when a [[Greek people|Greek]] [[Pythagoreanism|Pythagorean]] named [[Archytas]], propelled a wooden bird along wires using steam.<ref>{{cite book |author=Leofranc Holford-Strevens|title=Aulus Gellius: An Antonine Author and his Achievement|publisher=Oxford University Press|edition=Revised paperback |date=2005 |isbn=0-19-928980-8 }}
</ref><ref>{{cite EB1911 |wstitle=Archytas |volume=2 |page=446}}</ref> However, it was not powerful enough to take off under its own thrust.

The ''[[aeolipile]]'' described in the first century BC,<!--[[Vitruvius]] described it before Hero--> often known as ''[[Hero's engine]]'', consisted of a pair of [[steam rocket]] nozzles mounted on a [[Bearing (mechanical)|bearing]]. It was created almost two millennia before the [[Industrial Revolution]] but the principles behind it were not well understood, and it was not developed into a practical power source.

The availability of [[black powder]] to propel projectiles was a precursor to the development of the first solid rocket. Ninth Century [[Chinese people|Chinese]] [[Taoist]] [[Alchemy|alchemists]] discovered black powder in a search for the [[elixir of life]]; this accidental discovery led to [[fire arrow]]s which were the first rocket engines to leave the ground.

It is stated{{By whom|date=May 2022}} that "the reactive forces of incendiaries were probably not applied to the propulsion of projectiles prior to the 13th century".{{Citation needed|date=May 2024}} A turning point in rocket technology emerged with a short manuscript entitled ''Liber Ignium ad Comburendos Hostes'' (abbreviated as ''The Book of Fires''). The manuscript is composed of recipes for creating incendiary weapons from the mid-eighth to the end of the thirteenth centuries—two of which are rockets.  The first recipe calls for one part of colophonium and sulfur added to six parts of saltpeter (potassium nitrate) dissolved in [[Lauraceae|laurel]] oil, then inserted into hollow wood and lit to "fly away suddenly to whatever place you wish and burn up everything". The second recipe combines one pound of sulfur, two pounds of charcoal, and six pounds of saltpeter—all finely powdered on a marble slab. This powder mixture is packed firmly into a long and narrow case.  The introduction of saltpeter into pyrotechnic mixtures connected the shift from hurled [[Greek fire]] into self-propelled rocketry.<ref>{{cite book|last1=Von Braun|last2= Ordway III|first1=Wernher |first2= Frederick I.|title=The Rockets' Red Glare|url=https://archive.org/details/rocketsredglare0000vonb|url-access=registration|date=1976|publisher=Anchor Press/ Doubleday|location=Garden City, New York|isbn=978-0-385-07847-4|page=[https://archive.org/details/rocketsredglare0000vonb/page/5 5]}}</ref>

Articles and books on the subject of rocketry appeared increasingly from the fifteenth through seventeenth centuries.  In the sixteenth century, German military engineer Conrad Haas (1509–1576) wrote a manuscript which introduced the construction of multi-staged rockets.<ref>{{cite book|last1=Von Braun|last2= Ordway III|first1=Wernher |first2= Frederick I.|title=The Rockets' Red Glare|url=https://archive.org/details/rocketsredglare0000vonb|url-access=registration|date=1976|publisher=Anchor Press/ Doubleday|location=Garden City, New York|isbn=978-0-385-07847-4|page=[https://archive.org/details/rocketsredglare0000vonb/page/11 11]}}</ref>

Rocket engines were also put in use by [[Tippu Sultan]], the king of [[Mysore]]. These usually consisted of a tube of soft hammered iron about {{convert|8|in|cm|abbr=on}} long and {{convert|1+1/2|-|3|in|cm|abbr=on}} diameter, closed at one end, packed with black powder propellant and strapped to a shaft of bamboo about {{convert|4|ft|cm|abbr=on}} long. A rocket carrying about one pound of powder could travel almost {{convert|1000|yd|m}}. These 'rockets', fitted with swords, would travel several meters in the air before coming down with sword edges facing the enemy. These were used very effectively against the British empire.

===Modern rocketry===
Slow development of this technology continued up to the later 19th century, when Russian [[Konstantin Tsiolkovsky]] first wrote about [[liquid-propellant rocket|liquid-fuelled rocket engines]]. He was the first to develop the [[Tsiolkovsky rocket equation]], though it was not published widely for some years.

The modern solid- and liquid-fuelled engines became realities early in the 20th century, thanks to the American physicist [[Robert Goddard (scientist)|Robert Goddard]]. Goddard was the first to use a [[De Laval nozzle]] on a solid-propellant (gunpowder) rocket engine, doubling the thrust and increasing the efficiency by a factor of about twenty-five. This was the birth of the modern rocket engine. He calculated from his independently derived rocket equation that a reasonably sized rocket, using solid fuel, could place a one-pound payload on the Moon.

===The era of liquid-fuel rocket engines===
Goddard began to use liquid propellants in 1921, and in 1926 became the first to launch a liquid-fuelled rocket. Goddard pioneered the use of the De Laval nozzle, lightweight propellant tanks, small light turbopumps, thrust vectoring, the smoothly-throttled liquid fuel engine, regenerative cooling, and curtain cooling.<ref name=Sutton/>{{rp|247–266}}

During the late 1930s, German scientists, such as [[Wernher von Braun]] and [[Hellmuth Walter]], investigated installing liquid-fuelled rockets in military aircraft ([[Heinkel He 112]], [[Heinkel He 111|He 111]], [[Heinkel He 176|He 176]] and [[Messerschmitt Me 163]]).<ref>{{cite book|author=Lutz Warsitz|title=The First Jet Pilot – The Story of German Test Pilot Erich Warsitz|publisher=Pen and Sword Ltd.|date=2009|isbn=978-1-84415-818-8}} Includes von Braun's and Hellmuth Walter's experiments with rocket aircraft. [http://www.pen-and-sword.co.uk/?product_id=1762 English edition.]</ref>

The turbopump was employed by German scientists in World War II. Until then cooling the nozzle had been problematic, and the [[V-2 rocket|A4]] ballistic missile used dilute alcohol for the fuel, which reduced the combustion temperature sufficiently.

[[Staged combustion cycle (rocket)|Staged combustion]] (''Замкнутая схема'') was first proposed by [[Aleksei Mihailovich Isaev|Alexey Isaev]] in 1949. The first staged combustion engine was the S1.5400 used in the Soviet planetary rocket, designed by Melnikov, a former assistant to Isaev.<ref name=Sutton>{{cite book|last=Sutton|first=George P.|title=History of Liquid Propellant Rocket Engines|date=2005|publisher=American Institute of Aeronautics and Astronautics|location=Reston, Virginia}}</ref> About the same time (1959), [[Nikolai Dmitriyevich Kuznetsov|Nikolai Kuznetsov]] began work on the closed cycle engine [[NK-9]] for Korolev's orbital ICBM, GR-1. Kuznetsov later evolved that design into the [[NK-15]] and [[NK-33]] engines for the unsuccessful Lunar [[N1 rocket]].

In the West, the first laboratory staged-combustion test engine was built in Germany in 1963, by [[Ludwig Boelkow]].

Liquid hydrogen engines were first successfully developed in America: the [[RL-10]] engine first flew in 1962. Its successor, the [[Rocketdyne J-2]], was used in the [[Apollo program]]'s [[Saturn V]] rocket to send humans to the Moon. The high specific impulse and low density of liquid hydrogen lowered the upper stage mass and the overall size and cost of the vehicle.

The record for most engines on one rocket flight is 44, set by NASA in 2016 on a [[Black Brant (rocket)|Black Brant]].<ref>{{Cite web | url=https://www.space.com/33810-nasa-world-record-most-rocket-engines.html |title = NASA and Navy Set World Record for Most Engines in One Rocket Flight|website = [[Space.com]]|date = 19 August 2016}}</ref>