Editing Tractor beam (section)

==Fiction==
[[Image:Walton(reconstitution).png|thumb|Illustration of man being abducted with a tractor beam]]
[[Science fiction]] movies and telecasts normally depict tractor and repulsor beams as audible, narrow rays of visible light covering a small target area. Tractor beams are most commonly used on [[Spacecraft|spaceships]] and [[space stations]]. They are generally used in three ways:{{citation needed|date=July 2024}}
# As a device for securing or retrieving cargo, passengers, shuttlecraft, etc. This is analogous to [[crane (machine)|crane]]s on modern [[ship]]s.
# As a device to harness objects that can then be used as impromptu weapons by the craft
# As a means of preventing an enemy from escaping, analogous to [[grappling hook]]s.

In the latter case, countermeasures can usually be employed against tractor beams. These may include pressor beams (a stronger pressor beam will counteract a weaker tractor beam) or ''plane shears'' {{aka}} ''shearing planes'' (a device to "cut" the tractor beam and render it ineffective). In some fictional realities, [[energy shield|shields]] can block tractor beams, or the generators can be disabled by sending a large amount of energy along the beam to its source.{{citation needed|date=July 2024}}

Tractor beams and pressor beams can be used together as a weapon: by attracting one side of an enemy spaceship while repelling the other, one can create severely damaging shear effects in its hull. Another mode of destructive use of such beams is rapid alternating between pressing and pulling force in order to cause structural damage to the ship as well as inflicting lethal forces on its crew.{{citation needed|date=July 2024}}

Two objects being brought together by a tractor beam are usually attracted toward their common center of gravity. This means that if a small spaceship applies a tractor beam to a large object such as a planet, the ship will be drawn toward the planet, rather than vice versa.<ref name=":0" />{{better source|date=July 2024}}

In ''[[Star Trek]]'', tractor beams are imagined to work by placing a target in the focus of a subspace/graviton interference pattern created by two beams from an emitter. When the beams are manipulated correctly the target is drawn along with the interference pattern. The target may be moved toward or away from the emitter by changing the polarity of the beams. The range of the beam affects the maximum mass that the emitter can move, and the emitter subjects its anchoring structure to significant force.<ref>''Startrek Reference Manual'', Rick Sternbach and Michael Okuda, pages 89–90</ref>

===Literature===
* [[Rudyard Kipling]]'s ''As Easy as A.B.C.'' (1912) made use of the "flying loop", generated by one of the airships of the [[Aerial Board of Control]], when a woman tried, as a political statement, to publicly kill herself. The loop pulled the knife from her hand and, instead of drawing it toward the airship, flung it fifty yards away; it also continued to hold her arm rigid for a second or so afterward. [[John Brunner (novelist)|John Brunner]], in the foreword to a collection of Kipling's science fiction, said this may be the first depiction of a tractor beam.
* [[E. E. Smith]] coined the term "tractor beam" (an update of his earlier "attractor-beam") in his novel ''[[Spacehounds of IPC]]'', originally serialized in ''[[Amazing Stories]]'' magazine in 1931.  The hero of his ''[[Skylark of Space]]'' books (1929 onwards) had invented "attractor beams" and "repellor beams". Repellors can also be emitted [[isotropy|isotropically]] as a defensive [[Force field (fiction)|force field]] against material projectiles. The device also appears in Smith's ''[[Lensman]]'' books.
* In [[Philip Francis Nowlan]]'s [[Buck Rogers]] novel ''[[Armageddon 2419 A.D.]]'' (1928), the enemy airships used "repellor beams" for support and propulsion,<ref>Nowlan, P. F. (1962). ''Armageddon 2419 A. D.'' [pp. 37–41]. New York, NY: Ace Books, Inc.</ref> similar to the "eighth ray" beams used for support and propulsion of Martian airships in the [[Barsoom]]/John Carter of Mars series (first published 1912–1943) by [[Edgar Rice Burroughs]].
* ''[[Tom Swift]]'' – In the Tom Swift Jr. book ''Tom Swift and The Deep-Sea Hydrodome'' (1958), Tom invents the "repellatron". The device can be set to repel specific chemical elements. It was used to create a bubble habitat on the ocean floor, and as the propulsion system for his spacecraft ''Challenger''.
* The ''[[Sector General]]'' books by [[James White (author)|James White]]: The 1963 novel ''[[Star Surgeon]]'' is the source of the combined tractor/pressor beam weapon called the Rattler. The weapon attracts then repels the target (an entire ship or a segment of the ship's hull) at 80 ''[[g-force|g]]''s, several times a minute. The novel also featured a type of [[Force field (science fiction)|force field]] called a "repulsion screen".
* ''[[The Trigger]]'' by [[Arthur C. Clarke]] involves the development of tractor beams in the early part of the novel.
* ''[[Sixth Column]]'' by [[Robert A. Heinlein]] describes tractor/pressor beams as a product of the physics of a "newly-discovered magneto-gravitic or electro-gravitic spectra" featured in the novel.

===Comics===
* ''[[Buck Rogers]]'' comic strip – originally just repulsor-beams; tractors appeared by the 1970s
* [[Iron Man]]'s various armor suits usually feature repulsor beam projectors mounted in the palms as one of the main weapon systems.

===Movies and television series===
* ''[[Star Trek]]'' (TV series, films, books and games). One of the most visible and iconic uses of the concept. One of the few prominent fictitious depictions which used such beams repeatedly and referred to them consistently as tractor beams.{{citation needed|date=July 2024}}