Impulse drive
Encyclopedia
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
. 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.
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. Time dilation would become noticeable at appreciable fractions of the speed of light. Regarding energy conservation, the television series and books offer two explanations:
Impulse drives are also found in the online space simulation MMORPG, Ogame
.
Star Trek
Star Trek is an American science fiction entertainment franchise created by Gene Roddenberry. The core of Star Trek is its six television series: The Original Series, The Animated Series, The Next Generation, Deep Space Nine, Voyager, and Enterprise...
universe, the impulse drive is the method of propulsion that starships and other spacecraft
Spacecraft
A spacecraft or spaceship is a craft or machine designed for spaceflight. Spacecraft are used for a variety of purposes, including communications, earth observation, meteorology, navigation, planetary exploration and transportation of humans and cargo....
use when they are travelling below the speed of light
Speed of light
The speed of light in vacuum, usually denoted by c, is a physical constant important in many areas of physics. Its value is 299,792,458 metres per second, a figure that is exact since the length of the metre is defined from this constant and the international standard for time...
. Typically powered by deuterium fusion
Fusion
Fusion or synthesis, it refers to the connection of two or more distinct things/bodies:*Cell fusion, an event in the maturation of cells*Fusion cuisine, the combination of elements of various culinary traditions...
reactors, impulse engines let ships travel interplanetary distances readily. For example, Starfleet Academy
Starfleet Academy
In the fictional universe of Star Trek, Starfleet Academy is where the future's recruits to Starfleet will be trained. It was created in the year 2161, when the United Federation of Planets was founded...
cadets use impulse engines when flying from Earth
Earth
Earth is the third planet from the Sun, and the densest and fifth-largest of the eight planets in the Solar System. It is also the largest of the Solar System's four terrestrial planets...
to Saturn
Saturn
Saturn is the sixth planet from the Sun and the second largest planet in the Solar System, after Jupiter. Saturn is named after the Roman god Saturn, equated to the Greek Cronus , the Babylonian Ninurta and the Hindu Shani. Saturn's astronomical symbol represents the Roman god's sickle.Saturn,...
and back.
There are three practical challenges surrounding impulse drive design: acceleration
Acceleration
In physics, acceleration is the rate of change of velocity with time. In one dimension, acceleration is the rate at which something speeds up or slows down. However, since velocity is a vector, acceleration describes the rate of change of both the magnitude and the direction of velocity. ...
, time dilation
Time dilation
In the theory of relativity, time dilation is an observed difference of elapsed time between two events as measured by observers either moving relative to each other or differently situated from gravitational masses. An accurate clock at rest with respect to one observer may be measured to tick at...
and energy conservation
Energy conservation
Energy conservation refers to efforts made to reduce energy consumption. Energy conservation can be achieved through increased efficient energy use, in conjunction with decreased energy consumption and/or reduced consumption from conventional energy sources...
. 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. 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 ManualStar Trek: The Next Generation Technical ManualStar Trek: The Next Generation: Technical Manual is a paperback reference guide detailing the inner and other workings of the fictional Federation starship Enterprise-D and other aspects of technology that appeared in the television series Star Trek: The Next Generation.Authored by Rick Sternbach...
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 thrusterMagnetoplasmadynamic thrusterThe Magnetoplasmadynamic thruster is a form of electrically powered spacecraft propulsion which uses the Lorentz force to generate thrust...
. 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 DominionDominion (Star Trek)In the Star Trek universe, the Dominion is a ruthless and militaristic Gamma Quadrant state consisting of many different races. The Dominion wages war on the United Federation of Planets and its allies in the late 24th century, acting as an antagonist in the TV show Star Trek: Deep Space...
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, so high relativistic speeds are avoided unless absolutely necessary; impulse power is therefore customarily limited to a maximum of ¼ lightspeed. (WarpWarp drive (Star Trek)Warp drive is a faster-than-light propulsion system in the setting of many science fiction works, most notably Star Trek. A spacecraft equipped with a warp drive may travel at velocities greater than that of light by many orders of magnitude, while circumventing the relativistic problem of time...
travel, on the other hand, does not involve time dilation effects.)
Impulse drives are also found in the online space simulation MMORPG, Ogame
OGame
OGame is a text-based, resource-management and space-war themed massively multiplayer online browser game with over two million accounts. OGame was created in 2000 and is produced and maintained by Bioware.. OGame is available in multiple languages, and different nationalities have their own...
.
See also
- Physics and Star TrekPhysics and Star TrekThe science-fiction media franchise Star Trek has borrowed freely from the scientific world to provide storylines. Episodes are replete with references to tachyon beams, baryon sweeps, quantum fluctuations and event horizons...
- Physics and Star WarsPhysics and Star WarsThe science fantasy interstellar epic Star Wars uses science and technology in its settings and storylines, although it is not considered "hard" science fiction. The series has showcased many technological concepts, both in the movies and in the "Expanded Universe" of novels and comics...