Impulse drive

Impulse drive
Impulse drive
Star Trek franchise element
First appearance	Star Trek: The Original Series
Created by	Gene Roddenberry
Genre	Science fiction
In-universe information
Type	Propulsion system
Function	Allows rapid interplanetary travel

In the fictional Star Trek universe, the impulse drive is the method of propulsion that starships and other spacecraft use when they are travelling below the speed of light.^[1] Typically powered by deuterium fusion reactors, impulse engines let ships travel interplanetary distances readily. For example, Starfleet Academy cadets use impulse engines when flying from Earth to Saturn and back.^{[citation needed]}

An impulse drive is currently being researched with the cooperation of The University of Alabama's Aerophysics Research Center, NASA, Boeing, and Oak Ridge National Laboratory. They are all getting together to develop an impulse engine that's powered in part by dilithium crystals using Z-pinch fusion.

Since a fusion-driven impulse engine is far more efficient than a conventional rocket engine, you can go much farther, much faster, on a lot less fuel, meaning that a trip from Earth to Mars could take just six weeks instead of six months or more. And as for speed, the impulse engine may be able to propel a spacecraft at up to 62,600 miles per hour.

There are three practical challenges surrounding impulse drive design: acceleration, time dilation and energy conservation. In the show, inertial dampers compensate for acceleration. These hypothetical devices would have to be set so that the propellant regained its inertia after leaving the craft otherwise the drive would be ineffective.^[2] Time dilation would become noticeable at appreciable fractions of the speed of light. Regarding energy conservation, the television series and books offer two explanations:

Star Trek: The Next Generation Technical Manual indicates that the impulse engines are nuclear fusion engines where the plasma from the fusion reactor powers a massive magnetic coil to propel the ship. It is a form of magnetohydrodynamic or magnetoplasmadynamic thruster. This is used in conjunction with the ship's warp drive's alteration of the ship's relativistic mass, to achieve mid-to-high sub-light speeds. Thrusters, on the other hand, are closer to the designs of a high-efficiency reactant propellant (i.e. a sophisticated rocket engine) and are usually used for high-precision maneuvers. Ion propulsion drives are explicitly detailed to be used in Star Trek by Dominion and Iconian Starships and facilities.
Since a ship traveling at impulse velocities (slower than, but approaching, the speed of light) is still traveling in the normal space-time continuum, concerns of time dilation apply,and it is written in the ST:TNG Technical Manual that high relativistic speeds are avoided unless absolutely necessary; impulse power is therefore customarily limited to a maximum of ¼ lightspeed. (Warp travel, on the other hand, is stated in the Manual to cause no kinds of time dilation effects.)

References

^ Lawrence Krauss (20 April 1996), "Illogical Captain...", New Scientist (2026): 24
^ Marc G. Millis (2007), Energy Considerations of Hypothetical Space Drives (PDF), American Institute of Aeronautics and Astronautics, p. 3

References

See also