Editing Rocket (section)

=== Pendulum rocket fallacy ===
[[File:Pendulum rocket fallacy.png|thumb|Illustration of the pendulum rocket fallacy. Whether the motor is mounted at the bottom (left) or top (right) of the vehicle, the thrust vector (T) points along an axis that is fixed to the vehicle (top), rather than pointing vertically (bottom) independent of vehicle attitude, which would lead the vehicle to rotate.]]

The first [[liquid-fuel rocket]], constructed by [[Robert H. Goddard]], differed significantly from modern rockets. The [[rocket engine]] was at the top and the fuel tank at the bottom of the rocket,<ref>{{cite book |url=http://dln.nasa.gov/media/storage/DNY9-12activities.pdf |publisher=NASA |title=Discover NASA and You |archive-url=https://web.archive.org/web/20100527221503/http://dln.nasa.gov/media/storage/DNY9-12activities.pdf |archive-date=2010-05-27 |url-status=dead }}</ref> based on Goddard's belief that the rocket would achieve stability by "hanging" from the engine like a [[pendulum]] in flight.<ref>{{cite AV media |people=[[Scott Manley]] |title=The Pendulum Rocket Fallacy |medium=[[YouTube]] |url=https://www.youtube.com/watch?v=Tx4cjP-GRAY | archive-url=https://ghostarchive.org/varchive/youtube/20211030/Tx4cjP-GRAY| archive-date=2021-10-30|access-date=2020-10-02}}{{cbignore}}</ref> However, the rocket veered off course and crashed {{convert|184|ft}} away from the [[launch pad|launch site]],<ref>{{cite book|last=Streissguth|first=Thomas|title=Rocket man: the story of Robert Goddard|publisher=Twenty-First Century Books|year=1995|pages=[https://archive.org/details/rocketmanstoryof00stre/page/37 37]|isbn=0-87614-863-1|url-access=registration|url=https://archive.org/details/rocketmanstoryof00stre/page/37}}</ref> indicating that the rocket was no more stable than one with the rocket engine at the base.<ref name="Sutton">{{cite book|last=Sutton|first=George P.|title=History of Liquid Propellant Rocket Engines|year=2006|publisher=American Institute of Aeronautics and Astronautics|location=Reston, Virginia|pages=267, 269}}</ref>