In ST:TOS, while escaping the gravitational pull of a black hole, the USS Enterprise suffered the slingshot effect. It was thrown back in space-time by cut of stretched rubber band type force. The resultant destination was the earth of mid 20th century.

When the Enterprise was in the atmosphere escaping the gravity of Earth (with impulse drive), one of earth bases detected it and it was considered as an UFO. They sent a fighter jet to disable the Enterprise and the radio signal was captured by the Enterprise. The shield of the Enterprise was not working at that time and the fighter jet was equipped with nuclear warhead. So, Kirk ordered to trap the fighter jet using the tractor beam. But it crushed the fighter jet. Why? I think, Tractor Beam can be applied to even humans, safely.

3 Answers 3


The Short Answer:

The gravity field used by a tractor beam simply overwhelmed the relatively fragile fighter aircraft of the 20th century and crushed them, due to their lack of internal structural integrity fields and inferior construction as compared to superior armor and construction processes used in the design of the 23rd century starships.

A Longer Answer:

In Star Trek, where the tractor beam gained its cult popularity, it was a field of force designed to hold, tow, or control smaller vessels using an "attenuated graviton beam." The very utilitarian nature of the tractor beam, belies its potential destructive power. Indeed, the Borg use their tractor beams as weapons to hold ships in place, drain their shields and increase their targeting ability on a non-moving ship.

This field could reinforce structural integrity in vessels from the same era because it was designed to interact with the molecular structure of those ships. However, when used against ships or structures of a different era, particularly those without the benefit of structural integrity reinforcement, the tractor beam was the equivalent of a gravity weapon, tearing the vehicles apart.

While tractor beams were commonly used in the Federation and among Alpha Quadrant species, the process was not always a perfect one as different races found their tractor beams having different effects on each other's ships. A Romulan tractor beam was discovered to have a shearing effect (causing microscopic deformations in the hulls of Federation ships. (TNG: The Mind's Eye)

It is this same shearing effect, which tore apart the relatively flimsy 20th century fighter aircraft when a tractor beam was used to attempt to push them away from the Enterprise as it descended into low Earth orbit. The metallic hulls of those planes were simply not designed to withstand the force of the tractor and could not provide sufficient resistance to the equivalent of a giant fist squeezing the plane from the outside.

It is easy to forget how durable most Federation or 23rd century technology is in comparison to our own because their weaponry is so powerful. Most of the weapons of modern Earth could barely scratch an unshielded Federation starship. The molecular processes used to design their hulls make them incredibly strong and they are able to be reinforced with structural integrity fields, which constantly increase the rigidity and resistance to stresses from motion, inertia and other movement stresses up to and including moving near the speed of light! Modern Earth aircraft only have the strength of their materials, construction and design to help them withstand their operating stresses which a tractor beam can easily exceed.

As far as using the tractor beam on people, I cannot recall an instance where a shipboard tractor was ever used on an unprotected human, and if it was, it was probably highly modified in order not to harm the human. Normal ship tractors would and should crush unprotected human beings unless highly calibrated.

The episode in question is: "Tomorrow Is Yesterday" a first-season episode of Star Trek: The Original Series. It is episode #19, production #21, first broadcast on January 26, 1967, repeated July 13, 1967, and was remastered in 2006 for syndication broadcast on May 5, 2007. The teleplay was written by D.C. Fontana and directed by Michael O'Herlihy.

  • 1
    TL;DR - Man of Steel, Woman of Kleenex. Or, as I like to put it... Oops.
    – Omegacron
    Jul 2, 2015 at 13:52
  • Very accurate answer. Probably the only one UFO's (intended as alien being) sighting in human history 😉. It seems however no anomaly when the crew activate the tractor beam, indeed the jet's pilot starts to be affected by the deleterious effects of the beam, but immediately he's teleported on board. Probably the structure of the jet was making a sort of shield in those first instants of structural instability (as Mr Spock was detecting)
    – Bento
    Oct 17, 2020 at 4:31

The reason for the fighter's destruction was that it was resisting the effect of the tractor beam and that the plane was moving through the air at high speed.

Christopher was flying a Lockheed F-104 Starfighter, a supersonic interceptor capable of speeds beyond Mach 2. Since he was on a mission to confront a possibly hostile craft he was likely flying at supersonic speeds. Once his craft was forced to match speed and heading with the Enterprise by the tractor beam, it would have been held out of trim with the air flowing around it. This is very bad at supersonic speeds. The plane being at the wrong attitude along with the tractor beam pushing in opposition to its engines would have put heavy stress on the plane's fuselage, eventually breaking it apart.


You have to remember that the F-104 is an aircraft flying thru the atmosphere. The Enterprise tractor beam was designed for zero gravity and space vacuum.

When, Kirk ordered a tractor beam on the jet fighter he apparently did not know the tractor beam was going to be a bit too strong for an jet fighter.

And there was another thing that Mr. Spock apparently fail to know about and more likely was unaware of.

When he informed Captain Kirk this craft was designed to carry nuclear weapons and if he hits the Enterprise with one he could damaged the ship beyond their crew capability to repair it.

What Mr. Spock apparently did not know that to use a nuclear weapon in any form, it would required the orders from the President of the United States. Also, an F-104 carrying any nuclear weapons would have to one in an area to be needed in.. Since the F-104 had a limited range and Christopher F-104 was flying over the central United States it would not be carrying any nuclear weapons at all.. More likely any USAF F-104s that had nuclear weapons capability would more likely be on NATO bases in Europe, like Germany, Greece, Italy or Turkey and not the United States.

In other words, the crew on USS Enterprise panic.

  • There's no reason that it couldn't have been carrying nuclear weapons, at least not from the point of view of the Enterprise crew. They can't be expected to know how long it would take to get approval to use nukes, or that they wouldn't be deployed in US airspace.
    – DavidW
    Oct 17, 2020 at 0:21

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