Relativistic kill vehicle
Encyclopedia
A relativistic kill vehicle
(RKV) or relativistic bomb is a hypothetical weapon system sometimes found in science fiction
. The details of such systems vary widely, but the key common feature is the use of a massive impactor traveling at a significant fraction of light speed to strike the target. Therefore the weapon would be an extreme example of the real-life concept of a kinetic bombardment
.
RKVs have been proposed as a method of interstellar war
fare, especially in settings where faster than light travel or sensors are impossible. By traveling near the speed of light, an RKV could substantially limit the amount of early warning detection time. Furthermore, since the destructive effects of the RKV are carried by its kinetic energy, destroying the vehicle near its target would do little to reduce the damage; the cloud of particles or vapor would still be traveling at nearly the same speed and would have little time to disperse. Indeed, some versions of the RKV concept call for the RKV to explode shortly before impact to shower a wide region of space.
As providing terminal guidance for such a high-speed object would likely be difficult, RKVs are usually proposed as a strategic weapon targeted against large and predictable targets such as planet
s. However, they can still be used against smaller targets like spaceships, by aiming the weapons in the area they are in, and detonating a fuse in advance to shatter the mass into swarms of smaller particles, all traveling at nearly the same speed. This would cover a much larger area, and destroy smaller targets in space. Accelerating a mass to such velocities in the first place will likely require vast amounts of energy and large, unwieldy accelerators.
An RKV could theoretically be launched using any of the spacecraft propulsion
techniques that are capable of accelerating starship
s to relativistic velocities, such as antimatter rocket
s, Bussard ramjet
systems, or nuclear pulse propulsion
(see also relativistic rocket
s). Since an RKV would be unmanned, higher accelerations could be used (though with most propulsion methods high acceleration may not be the most efficient approach).
In some science fiction smaller relativistic projectiles can sometimes be found depending on the technologies imagined in any particular scenario. In the movie Eraser, for example, characters used man-portable "gauss rifles" that were able to fire bullets at relativistic velocities. Man-portable weapons of this type would have extreme issues with recoil, however; accelerating a 1-gram projectile up to a mere 1% of light speed would produce enough force to send a 100 kg (220 pound) man flying backward at 30 meters per second (98 feet per second or 67 miles per hour). A further difficulty is reaching such high speeds over such a short distance; to reach 1% of light speed over the length of a one-meter accelerator would require (or over 450 billion g
) of acceleration. Space-based RKVs have the advantage of being able to accelerate over a vastly longer distance and period of time.
formula for kinetic energy
, given as
, is only an approximation for the kinetic energy of an object, reasonably accurate for speeds well below c
, approximately 3 × 108 m s−1. For higher speeds, Einstein's
formula for kinetic energy, Ek, must be used.
Where:
m is the object's mass in kg,
c
is the speed of light in m s−1,
is the Lorentz factor
, given by:
Where v is the velocity of the object in question.
Therefore, expanded the equation is:
, the most powerful nuclear weapon ever detonated. 1 kg of mass-energy is 8.99×1016 joules or about 21.5 megatons of TNT.
Kill vehicle
Kill vehicle is a term from space weapon development and science fiction which denotes either a kinetic projectile or an explosive warhead supposed to impact on or near a target...
(RKV) or relativistic bomb is a hypothetical weapon system sometimes found in science fiction
Science fiction
Science fiction is a genre of fiction dealing with imaginary but more or less plausible content such as future settings, futuristic science and technology, space travel, aliens, and paranormal abilities...
. The details of such systems vary widely, but the key common feature is the use of a massive impactor traveling at a significant fraction of light speed to strike the target. Therefore the weapon would be an extreme example of the real-life concept of a kinetic bombardment
Kinetic bombardment
A kinetic bombardment is the act of attacking a planetary surface with an inert projectile, where the destructive force comes from the kinetic energy of the projectile impacting at very high velocities...
.
RKVs have been proposed as a method of interstellar war
Interstellar war
In fiction, an interstellar war is a war between combatants whose respective headquarters lie in different planetary systems. It is a popular plot device in science fiction, especially in the space opera subgenre. An intergalactic war refers to war between combatants of different galaxies...
fare, especially in settings where faster than light travel or sensors are impossible. By traveling near the speed of light, an RKV could substantially limit the amount of early warning detection time. Furthermore, since the destructive effects of the RKV are carried by its kinetic energy, destroying the vehicle near its target would do little to reduce the damage; the cloud of particles or vapor would still be traveling at nearly the same speed and would have little time to disperse. Indeed, some versions of the RKV concept call for the RKV to explode shortly before impact to shower a wide region of space.
As providing terminal guidance for such a high-speed object would likely be difficult, RKVs are usually proposed as a strategic weapon targeted against large and predictable targets such as planet
Planet
A planet is a celestial body orbiting a star or stellar remnant that is massive enough to be rounded by its own gravity, is not massive enough to cause thermonuclear fusion, and has cleared its neighbouring region of planetesimals.The term planet is ancient, with ties to history, science,...
s. However, they can still be used against smaller targets like spaceships, by aiming the weapons in the area they are in, and detonating a fuse in advance to shatter the mass into swarms of smaller particles, all traveling at nearly the same speed. This would cover a much larger area, and destroy smaller targets in space. Accelerating a mass to such velocities in the first place will likely require vast amounts of energy and large, unwieldy accelerators.
An RKV could theoretically be launched using any of the spacecraft propulsion
Spacecraft propulsion
Spacecraft propulsion is any method used to accelerate spacecraft and artificial satellites. There are many different methods. Each method has drawbacks and advantages, and spacecraft propulsion is an active area of research. However, most spacecraft today are propelled by forcing a gas from the...
techniques that are capable of accelerating starship
Starship
A starship or interstellar spacecraft is a theoretical spacecraft designed for traveling between the stars, as opposed to a vehicle designed for orbital spaceflight or interplanetary travel....
s to relativistic velocities, such as antimatter rocket
Antimatter rocket
An antimatter rocket is a proposed class of rockets that use antimatter as their power source. There are several designs that attempt to accomplish this goal...
s, Bussard ramjet
Bussard ramjet
The Bussard ramjet is a theoretical method of spacecraft propulsion proposed in 1960 by the physicist Robert W. Bussard, popularized by Larry Niven in his Known Space series of books, and referred to by Carl Sagan in the television series and book Cosmos....
systems, or nuclear pulse propulsion
Nuclear pulse propulsion
Nuclear pulse propulsion is a proposed method of spacecraft propulsion that uses nuclear explosions for thrust. It was first developed as Project Orion by DARPA, after a suggestion by Stanislaw Ulam in 1947...
(see also relativistic rocket
Relativistic rocket
A relativistic rocket is any spacecraft that is travelling at a velocity close enough to light speed for relativistic effects to become significant. What "significant" means is a matter of context, but generally speaking a velocity of at least 50% of the speed of light is required...
s). Since an RKV would be unmanned, higher accelerations could be used (though with most propulsion methods high acceleration may not be the most efficient approach).
In some science fiction smaller relativistic projectiles can sometimes be found depending on the technologies imagined in any particular scenario. In the movie Eraser, for example, characters used man-portable "gauss rifles" that were able to fire bullets at relativistic velocities. Man-portable weapons of this type would have extreme issues with recoil, however; accelerating a 1-gram projectile up to a mere 1% of light speed would produce enough force to send a 100 kg (220 pound) man flying backward at 30 meters per second (98 feet per second or 67 miles per hour). A further difficulty is reaching such high speeds over such a short distance; to reach 1% of light speed over the length of a one-meter accelerator would require (or over 450 billion g
G-force
The g-force associated with an object is its acceleration relative to free-fall. This acceleration experienced by an object is due to the vector sum of non-gravitational forces acting on an object free to move. The accelerations that are not produced by gravity are termed proper accelerations, and...
) of acceleration. Space-based RKVs have the advantage of being able to accelerate over a vastly longer distance and period of time.
Calculating energy content
Newton'sIsaac Newton
Sir Isaac Newton PRS was an English physicist, mathematician, astronomer, natural philosopher, alchemist, and theologian, who has been "considered by many to be the greatest and most influential scientist who ever lived."...
formula for kinetic energy
Kinetic energy
The kinetic energy of an object is the energy which it possesses due to its motion.It is defined as the work needed to accelerate a body of a given mass from rest to its stated velocity. Having gained this energy during its acceleration, the body maintains this kinetic energy unless its speed changes...
, given as
, is only an approximation for the kinetic energy of an object, reasonably accurate for speeds well below cSpeed 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...
, approximately 3 × 108 m s−1. For higher speeds, Einstein's
Albert Einstein
Albert Einstein was a German-born theoretical physicist who developed the theory of general relativity, effecting a revolution in physics. For this achievement, Einstein is often regarded as the father of modern physics and one of the most prolific intellects in human history...
formula for kinetic energy, Ek, must be used.
Where:
m is the object's mass in kg,
c
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...
is the speed of light in m s−1,
is the Lorentz factorLorentz factor
The Lorentz factor or Lorentz term appears in several equations in special relativity, including time dilation, length contraction, and the relativistic mass formula. Because of its ubiquity, physicists generally represent it with the shorthand symbol γ . It gets its name from its earlier...
, given by:
Where v is the velocity of the object in question.
Therefore, expanded the equation is:
Example
A 1 kg mass traveling at 99% of the speed of light would have a kinetic energy of 5.47×1017 joules. In explosive terms, it would be equal to 132 megatons of TNT or approximately 32 megatons more than the theoretical max yield of the tsar bombaTsar Bomba
Tsar Bomba is the nickname for the AN602 hydrogen bomb, the most powerful nuclear weapon ever detonated. It was also referred to as Kuz'kina Mat , in this usage meaning "something that has not been seen before"....
, the most powerful nuclear weapon ever detonated. 1 kg of mass-energy is 8.99×1016 joules or about 21.5 megatons of TNT.
Examples of RKVs in fiction
- A good example of RKV use in science fiction novels is in Charles R. PellegrinoCharles R. PellegrinoCharles R. Pellegrino is the controversial author of several books relating to science and archaeology, including Return to Sodom and Gomorrah, Ghosts of the Titanic, Unearthing Atlantis and Ghosts of Vesuvius....
and George ZebrowskiGeorge ZebrowskiGeorge Zebrowski is a science fiction author and editor who has written and edited a number of books. He lives with author Pamela Sargent, with whom he has co-written a number of novels, including Star Trek novels.Zebrowski won the John W. Campbell Memorial Award in 1999 for his novel Brute Orbits...
's The Killing StarThe Killing StarThe Killing Star is a hard science fiction novel by Charles R. Pellegrino and George Zebrowski, published in April, 1995. It covers several familiar speculative fiction ideas such as sublight interstellar travel, genetic cloning, virtual reality, advanced robotics, alien contact, and interstellar...
and Flying to Valhalla, wherein aliens exterminate all human life on Earth by kinetic weapons traveling at relativistic velocities called "R-bombs". - Probably the first example of RKV, although that term was not used, was in PK Dick's 1953 novella, The Variable ManThe Variable ManThe Variable Man is a novella written and sold by Philip K. Dick before he had an agent. It was first published in Space Science Fiction , Vol. 2 No. 2, July 1953 and Space Science Fiction, September 1953 with the US publication illustrated by Alex Ebel...
. Here the Earth is fighting a war against Proxima Centauri and is constructing a bomb based on relativistic principles. - W. Michael GearW. Michael GearW. Michael Gear is an American writer, and archaeologist born in Colorado Springs, Colorado on May 20, 1955. He is perhaps best known for his First North Americans series, co-authored with wife Kathleen O'Neal Gear.-Biography:...
's Forbidden Borders trilogyForbidden Borders trilogyThe Forbidden Borders trilogy, written by W. Michael Gear includes Requiem for the Conqueror, Relic of Empire, and Countermeasures. They describe the political power play in a universe where humanity is forced to exist in a limited space bound by the Forbidden Borders....
, Requiem for the ConquerorRequiem for the Conqueror-Plot introduction:Set in a future when humanity has forgotten its origins in earth, the novel describes the political equations and power struggle between the emperor, a quasireligious group, a pre-sentient computer named the Magcomm and the Lord Commander....
, Relic of EmpireRelic of Empire-Plot introduction:Set in a future when humanity has forgotten its origins in Earth, the novel describes the political equations and power struggle between the emperor, a quasi-religious group, a pre-sentient computer named the Mag Comm and the Lord Commander....
and Countermeasures also include RKVs. - In A Fire Upon the DeepA Fire Upon the DeepA Fire Upon the Deep is a science fiction novel by American writer Vernor Vinge, a space opera involving superhuman intelligences, aliens, variable physics, space battles, love, betrayal, genocide, and a conversation medium resembling Usenet...
by Vernor VingeVernor VingeVernor Steffen Vinge is a retired San Diego State University Professor of Mathematics, computer scientist, and science fiction author. He is best known for his Hugo Award-winning novels and novellas A Fire Upon the Deep , A Deepness in the Sky , Rainbows End , Fast Times at Fairmont High ...
, the destruction of a human civilization is preceded by an RKV assault. - In Iron SunriseIron SunriseIron Sunrise is a 2004 hard science fiction novel by author Charles Stross, which follows the events in Singularity Sky. The book was nominated for both the Hugo and Locus Awards in 2005....
by Charles StrossCharles StrossCharles David George "Charlie" Stross is a British writer of science fiction, Lovecraftian horror and fantasy. He was born in Leeds.Stross specialises in hard science fiction and space opera...
, attempts are made to obtain the deactivation codes which will stop a destroyed planet's automated RKV retaliation from destroying another world. - In David WeberDavid WeberDavid Mark Weber is an American science fiction and fantasy author. He was born in Cleveland, Ohio. Weber and his wife Sharon live in Greenville, South Carolina with their three children and "a passel of dogs"....
's Honor HarringtonHonor HarringtonHonor Stephanie Alexander-Harrington is a fictional character, the heroine of a series of military science fiction books set in the "Honorverse", written by David Weber and published by Baen Books....
series, RKVs are mentioned as a historical weapon, later banned as uncivilized. - In Joe HaldemanJoe HaldemanJoe William Haldeman is an American science fiction author.-Life :Haldeman was born June 9, 1943 in Oklahoma City, Oklahoma. His family traveled and he lived in Puerto Rico, New Orleans, Washington, D.C., Bethesda, Maryland and Anchorage, Alaska as a child. Haldeman married Mary Gay Potter, known...
's The Forever WarThe Forever WarThe Forever War is a science fiction novel by American author Joe Haldeman, telling the contemplative story of soldiers fighting an interstellar war between humanity and the enigmatic Tauran species...
, a comparatively lightly armed human spaceship uses two drones traveling at relativistic speeds to destroy a much larger enemy battlecruiser and, accidentally, part of a nearby moon. - In Harry TurtledoveHarry TurtledoveHarry Norman Turtledove is an American novelist, who has produced works in several genres including alternate history, historical fiction, fantasy and science fiction.- Life :...
's book Homeward Bound, the threat of RKV's is mentioned by The RaceThe Race (Worldwar)The Race refers to the fictional alien invaders of Harry Turtledove's Worldwar tetralogy, Colonization trilogy and Homeward Bound...
as a means of possible interplanetary Mutually Assured Destruction - In Larry NivenLarry NivenLaurence van Cott Niven / ˈlæri ˈnɪvən/ is an American science fiction author. His best-known work is Ringworld , which received Hugo, Locus, Ditmar, and Nebula awards. His work is primarily hard science fiction, using big science concepts and theoretical physics...
's 'Known SpaceKnown SpaceKnown Space is the fictional setting of some dozen science fiction novels and several collections of short stories written by author Larry Niven. It has also in part been used as a shared universe in the Man-Kzin Wars spin-off anthologies sub-series....
' setting (specifically the 'Man-Kzin WarsMan-Kzin WarsThe Man-Kzin Wars is a series of military science fiction short story collections , as well as the eponymous conflicts between mankind and the Kzinti that they detail...
' shared-world series), RKVs were used as part of the counterattack against the Kzinti occupation of the Alpha Centauri system, striking the planet Wunderland with a combined energy release equaling 12 gigatons of TNT. - In issue 18 of Marvel Comics' Supreme PowerSupreme PowerThe Squadron Supreme is a fictional superhero team that appears in publications under the mature-audience MAX imprint by Marvel Comics. The team first appears in Supreme Power #1 and was created by writer J...
series, the main character Hyperion uses his indestructible body as an RKV, slamming himself into the far Northern Hemisphere with enough force to generate a one teratonTeratonA teraton is the equivalent, in SI terms, of being 1.00×1012 tons; 1,000 gigatons; 1,000,000 megatons; 1,000,000,000 kilotons; or 1,000,000,000,000 tons in its entirely expanded form....
explosion. - The Jack WilliamsonJack WilliamsonJohn Stewart Williamson , who wrote as Jack Williamson was a U.S. writer often referred to as the "Dean of Science Fiction" following the death in 1988 of Robert A...
story "Nowhere Near" features robots of a defunct alien race that defend their derelict spaceships with BB sized "micro missiles" launched at a substantial fraction of light speed. - In the webcomic Schlock MercenarySchlock MercenarySchlock Mercenary is a comedic webcomic written and drawn by Howard Tayler. It follows the tribulations of a star-travelling mercenary company in a satiric, mildly dystopian 31st-century space opera setting...
, RKVs of various sorts are used, such as the cee-sabots deployed by the Partnership Collective fleet and the Tohdfraug assault on the planet Qlaviql. - In the video game series Halo, over three hundred orbital defense platforms have been positioned by the United Nations Space Command in defense of Earth. These Super-MAC stations fire magnetically acceleratedMass driverA mass driver or electromagnetic catapult is a proposed method of non-rocket spacelaunch which would use a linear motor to accelerate and catapult payloads up to high speeds. All existing and contemplated mass drivers use coils of wire energized by electricity to make electromagnets. Sequential...
projectiles which weigh hundreds of tons and travel at approximately 40% of the speed of light. - In the Marvel Comic Astonishing X-MenAstonishing X-MenAstonishing X-Men is the name of three X-Men comic book series from Marvel Comics, the first two of which were limited series. The ongoing series began in 2004, with its first run written by Joss Whedon and art by John Cassaday. It was then written by Warren Ellis with art by Phil Jimenez. Daniel...
by Joss WhedonJoss WhedonJoseph Hill "Joss" Whedon is an American screenwriter, executive producer, director, comic book writer, occasional composer and actor, founder of Mutant Enemy Productions and co-creator of Bellwether Pictures...
the aliens of the Breakworld fire a RKV shaped like a giant bullet at the earth, fearing that an earth-born mutant will one day destroy their planet. The bullet is not stopped, but phases through the earth thanks to Shadowcat who risks her life to do so. - In the Mass EffectMass EffectMass Effect is an action role-playing game developed by BioWare for the Xbox 360 and Microsoft Windows by Demiurge Studios. The Xbox 360 version was released worldwide in November 2007 published by Microsoft Game Studios...
series, most spacefaring species utilize spinal-mounted mass accelerators in their warships to accelerate ferro-slugs to 1.3% of light speed. Mass Effect 2 has a scene of a drill instructor citing Newton's first law and warning a pair of trainees that "eyeballing" such a weapon of mass destruction without a firing solution must be avoided at all costs since a RKV will not stop until it hits something; in the instructor's own words, "that could be a ship, or the planet behind that ship; it might even go off into deep space and hit somebody else in ten thousand years". In fact, there is a planet with a gigantic canyon on its surface, said to have been dug millennia ago by a glancing blow from a mass accelerator fired lightyears away; the protagonist uses it to track down the location of the battle where the weapon was fired. The Reapers use a more powerful version firing molten streams of metal. In Mass Effect 2, the Turians reverse-engineer the Reaper version into the smaller Thanix Cannon that can optionally be mounted on the protagonist's ship for use in the final battle. - In the Orion's ArmOrion's ArmOrion's Arm, is a multi-authored online science fiction world-building project, first established in 2000 by M. Alan Kazlev, Donna Malcolm Hirsekorn, Bernd Helfert and Anders Sandberg and further co-authored by many people since...
project Relativistic Kinetic Kill Systems (RKKS pronounced "rocks") are 100,000 ton RKVs traveling at 99.9% the speed of light which sterilize planets. - In John VarleyJohn VarleyJohn Varley may refer to:* John Varley , English canal engineer* John Varley , English painter and astrologer* John Varley , American science fiction author...
's book Red Lightning an object traveling at near-lightspeed bounces off Earth causing a massive tsunami in the Atlantic. Authorities believe that the object is a spaceship that has been deliberately directed at the planet. The ship is incorrectly aimed and bounces off planet Earth.