
A kinetic energy weapon (also known as kinetic weapon, kinetic energy warhead, kinetic warhead, kinetic projectile, kinetic kill vehicle) is a projectile weapon based solely on a
projectile
A projectile is an object that is propelled by the application of an external force and then moves freely under the influence of gravity and air resistance. Although any objects in motion through space are projectiles, they are commonly found ...
's
kinetic energy
In physics, the kinetic energy of an object is the form of energy that it possesses due to its motion.
In classical mechanics, the kinetic energy of a non-rotating object of mass ''m'' traveling at a speed ''v'' is \fracmv^2.Resnick, Rober ...
to inflict
damage
Damage is any change in a thing, often a physical object, that degrades it away from its initial state. It can broadly be defined as "changes introduced into a system that adversely affect its current or future performance".Farrar, C.R., Sohn, H., ...
to a target, instead of using any
explosive
An explosive (or explosive material) is a reactive substance that contains a great amount of potential energy that can produce an explosion if released suddenly, usually accompanied by the production of light, heat, sound, and pressure. An ex ...
,
incendiary,
chemical
A chemical substance is a unique form of matter with constant chemical composition and characteristic properties. Chemical substances may take the form of a single element or chemical compounds. If two or more chemical substances can be combin ...
or
radiological
In physics, radiation is the emission or transmission of energy in the form of waves or particles through space or a material medium. This includes:
* ''electromagnetic radiation'' consisting of photons, such as radio waves, microwaves, infr ...
payload
Payload is the object or the entity that is being carried by an aircraft or launch vehicle. Sometimes payload also refers to the carrying capacity of an aircraft or launch vehicle, usually measured in terms of weight. Depending on the nature of t ...
. All kinetic weapons work by attaining a high flight speedgenerally
supersonic
Supersonic speed is the speed of an object that exceeds the speed of sound (Mach 1). For objects traveling in dry air of a temperature of 20 °C (68 °F) at sea level, this speed is approximately . Speeds greater than five times ...
or even up to
hypervelocity
Hypervelocity is very high velocity, approximately over 3,000 meters per second (11,000 km/h, 6,700 mph, 10,000 ft/s, or Mach 8.8). In particular, hypervelocity is velocity so high that the strength of materials upon impact is v ...
and
collide with their targets, converting their kinetic energy and relative
impulse
Impulse or Impulsive may refer to:
Science
* Impulse (physics), in mechanics, the change of momentum of an object; the integral of a force with respect to time
* Impulse noise (disambiguation)
* Specific impulse, the change in momentum per unit ...
into destructive
shock wave
In physics, a shock wave (also spelled shockwave), or shock, is a type of propagating disturbance that moves faster than the local speed of sound in the medium. Like an ordinary wave, a shock wave carries energy and can propagate through a me ...
s,
heat
In thermodynamics, heat is energy in transfer between a thermodynamic system and its surroundings by such mechanisms as thermal conduction, electromagnetic radiation, and friction, which are microscopic in nature, involving sub-atomic, ato ...
and
cavitation
Cavitation in fluid mechanics and engineering normally is the phenomenon in which the static pressure of a liquid reduces to below the liquid's vapor pressure, leading to the formation of small vapor-filled cavities in the liquid. When sub ...
. In kinetic weapons with
unpowered flight
Unpowered flight is the ability to stay airborne for a period of time without using any power source. There are several types of unpowered flight. Some have been exploited by nature, others by humankind, and some by both.
Unpowered aircraft are a ...
, the
muzzle velocity
Muzzle velocity is the speed of a projectile (bullet, pellet, slug, ball/ shots or shell) with respect to the muzzle at the moment it leaves the end of a gun's barrel (i.e. the muzzle). Firearm muzzle velocities range from approximately t ...
or
launch velocity often determines the
effective range
Effective range is a term with several definitions depending upon context.
Distance
Effective range may describe a distance between two points where one point is subject to an energy release at the other point. The source, receiver, and conditio ...
and
potential damage of the kinetic projectile.
Kinetic weapons are the oldest and most common ranged weapons used in
human history
Human history or world history is the record of humankind from prehistory to the present. Early modern human, Modern humans evolved in Africa around 300,000 years ago and initially lived as hunter-gatherers. They Early expansions of hominin ...
, with the projectiles varying from blunt projectiles such as
rocks
In geology, rock (or stone) is any naturally occurring solid mass or aggregate of minerals or mineraloid matter. It is categorized by the minerals included, its chemical composition, and the way in which it is formed. Rocks form the Earth's ...
and
round shot
A round shot (also called solid shot or simply ball) is a solid spherical projectile without explosive charge, launched from a gun. Its diameter is slightly less than the bore of the barrel from which it is shot. A round shot fired from a lar ...
s, pointed missiles such as
arrow
An arrow is a fin-stabilized projectile launched by a bow. A typical arrow usually consists of a long, stiff, straight shaft with a weighty (and usually sharp and pointed) arrowhead attached to the front end, multiple fin-like stabilizers c ...
s,
bolts,
darts
Darts is a competitive sport in which two or more players bare-handedly throw small projectile point, sharp-pointed projectile, projectiles known as dart (missile), darts at a round shooting target, target known as a #Dartboard, dartboard.
Point ...
, and
javelin
A javelin is a light spear designed primarily to be thrown, historically as a ranged weapon. Today, the javelin is predominantly used for sporting purposes such as the javelin throw. The javelin is nearly always thrown by hand, unlike the sling ...
s, to modern tapered high-velocity impactors such as
bullet
A bullet is a kinetic projectile, a component of firearm ammunition that is shot from a gun barrel. They are made of a variety of materials, such as copper, lead, steel, polymer, rubber and even wax; and are made in various shapes and constru ...
s,
flechette
A flechette or flèchette ( ) is a pointed, fin-stabilized steel projectile. The name comes from French (from \''wikt:flèche, flèche''), meaning "little arrow" or "Dart (missile), dart", and sometimes retains the grave accent in English: flè ...
s, and
penetrators. Typical kinetic weapons accelerate their projectiles mechanically (by
muscle power,
mechanical advantage device
A simple machine that exhibits mechanical advantage is called a mechanical advantage device - e.g.:
* Lever: The Beam (structure), beam shown is in static equilibrium around the wikt:fulcrum, fulcrum. This is due to the Moment (physics), moment ...
s,
elastic energy
Elastic energy is the mechanical potential energy stored in the configuration of a material or physical system as it is subjected to elastic deformation by work performed upon it. Elastic energy occurs when objects are impermanently compressed ...
or
pneumatics
Pneumatics (from Greek 'wind, breath') is the use of gas or pressurized air in mechanical systems.
Pneumatic systems used in industry are commonly powered by compressed air or compressed inert gases. A centrally located and electrically- ...
) or chemically (by
propellant
A propellant (or propellent) is a mass that is expelled or expanded in such a way as to create a thrust or another motive force in accordance with Newton's third law of motion, and "propel" a vehicle, projectile, or fluid payload. In vehicle ...
combustion
Combustion, or burning, is a high-temperature exothermic redox chemical reaction between a fuel (the reductant) and an oxidant, usually atmospheric oxygen, that produces oxidized, often gaseous products, in a mixture termed as smoke. Combustion ...
, as with
firearm
A firearm is any type of gun that uses an explosive charge and is designed to be readily carried and operated by an individual. The term is legally defined further in different countries (see legal definitions).
The first firearms originate ...
s), but newer technologies are enabling the development of potential weapons using
electromagnetic
In physics, electromagnetism is an interaction that occurs between particles with electric charge via electromagnetic fields. The electromagnetic force is one of the four fundamental forces of nature. It is the dominant force in the interacti ...
ally launched projectiles, such as
railgun
A railgun or rail gun, sometimes referred to as a rail cannon, is a linear motor device, typically designed as a ranged weapon, that uses Electromagnet, electromagnetic force to launch high-velocity Projectile, projectiles. The projectile norma ...
s,
coilgun
A coilgun is a type of mass driver consisting of one or more coils used as electromagnets in the configuration of a linear motor that accelerate a ferromagnetic or conducting projectile to high velocity. In almost all coilgun configurations, t ...
s and
mass driver
A mass driver or electromagnetic catapult is a proposed method of non-rocket spacelaunch which would use a linear motor to Acceleration, accelerate and catapult Payload (air and space craft), payloads up to high speeds. Existing and proposed mass ...
s. There are also concept weapons that are accelerated by
gravity
In physics, gravity (), also known as gravitation or a gravitational interaction, is a fundamental interaction, a mutual attraction between all massive particles. On Earth, gravity takes a slightly different meaning: the observed force b ...
, as in the case of
kinetic bombardment weapons designed for
space warfare
Space warfare is combat in which one or more belligerents are in outer space. The scope of space warfare includes ''ground-to-space warfare'', such as attacking satellites from the Earth; ''space-to-space warfare'', such as satellites attacki ...
.
The term hit-to-kill, or kinetic kill, is also used in the military
aerospace
Aerospace is a term used to collectively refer to the atmosphere and outer space. Aerospace activity is very diverse, with a multitude of commercial, industrial, and military applications. Aerospace engineering consists of aeronautics and astron ...
field to describe kinetic energy weapons accelerated by a
rocket engine
A rocket engine is a reaction engine, producing thrust in accordance with Newton's third law by ejecting reaction mass rearward, usually a high-speed Jet (fluid), jet of high-temperature gas produced by the combustion of rocket propellants stor ...
. It has been used primarily in the
anti-ballistic missile
An anti-ballistic missile (ABM) is a surface-to-air missile designed to Missile defense, destroy in-flight ballistic missiles. They achieve this explosively (chemical or nuclear), or via hit-to-kill Kinetic projectile, kinetic vehicles, which ma ...
(ABM) and
anti-satellite weapon
Anti-satellite weapons (ASAT) are space weapons designed to incapacitate or destroy satellites for Military strategy, strategic or Military tactics, tactical purposes. Although no ASAT system has been utilized in warfare, a few countries (China, ...
(ASAT) fields, but some modern
anti-aircraft missiles are also kinetic kill vehicles. Hit-to-kill systems are part of the wider class of kinetic projectiles, a class that has widespread use in the
anti-tank
Anti-tank warfare refers to the military strategies, tactics, and weapon systems designed to counter and destroy enemy armored vehicles, particularly tanks. It originated during World War I following the first deployment of tanks in 1916, and ...
field.
Basic concept
Kinetic energy
In physics, the kinetic energy of an object is the form of energy that it possesses due to its motion.
In classical mechanics, the kinetic energy of a non-rotating object of mass ''m'' traveling at a speed ''v'' is \fracmv^2.Resnick, Rober ...
is a function of mass and the velocity of an object. For a kinetic energy weapon in the aerospace field, both objects are moving and it is the
relative velocity
The relative velocity of an object ''B'' relative to an observer ''A'', denoted \mathbf v_ (also \mathbf v_ or \mathbf v_), is the velocity vector of ''B'' measured in the rest frame of ''A''.
The relative speed v_ = \, \mathbf v_\, is the v ...
that is important. In the case of the interception of a
reentry vehicle
Atmospheric entry (sometimes listed as Vimpact or Ventry) is the movement of an object from outer space into and through the gases of an atmosphere of a planet, dwarf planet, or natural satellite. Atmospheric entry may be ''uncontrolled entr ...
(RV) from an
intercontinental ballistic missile
An intercontinental ballistic missile (ICBM) is a ballistic missile with a range (aeronautics), range greater than , primarily designed for nuclear weapons delivery (delivering one or more Thermonuclear weapon, thermonuclear warheads). Conven ...
(ICBM) during the terminal phase of the approach, the RV will be traveling at approximately while the interceptor will be on the order of . Because the interceptor may not be approaching head-on, a lower bound on the relative velocity on the order of can be assumed, or converting to SI units, approximately .
At that speed, every kilogram of the interceptor will have an energy of:
TNT
Troponin T (shortened TnT or TropT) is a part of the troponin complex, which are proteins integral to the contraction of skeletal and heart muscles. They are expressed in skeletal and cardiac myocytes. Troponin T binds to tropomyosin and helps ...
has an explosive energy of about 4,853
joules
The joule ( , or ; symbol: J) is the unit of energy in the International System of Units (SI). In terms of SI base units, one joule corresponds to one kilogram- metre squared per second squared One joule is equal to the amount of work don ...
per gram, or about 5 MJ per kilogram. That means the impact energy of the mass of the interceptor is over five times that of a detonating warhead of the same mass.
It may seem like this makes a warhead superfluous, but a hit-to-kill system has to actually hit the target, which may be on the order of half a meter wide, while a conventional warhead releases numerous small fragments that increase the possibility of impact over a much larger area, albeit with a much smaller impact mass. This has led to alternative concepts that attempt to spread out the potential impact zone without explosives. The SPAD concept of the 1960s used a metal net with small steel balls that would be released from the interceptor missile, while the
Homing Overlay Experiment of the 1980s used a fan-like metal disk.
As the accuracy and speed of modern
surface-to-air missile
A surface-to-air missile (SAM), also known as a ground-to-air missile (GTAM) or surface-to-air guided weapon (SAGW), is a missile designed to be launched from the ground or the sea to destroy aircraft or other missiles. It is one type of anti-ai ...
s (SAMs) improved, and their targets began to include
theatre ballistic missile
A theatre ballistic missile (TBM) is any ballistic missile used against targets "Theater (warfare), in-theatre". Examples of this type of in-theatre missile are the Soviet Union, Soviet RT-15, TR-1 Temp and United States, American PGM-19 Jupiter ...
s (TBMs), many existing systems have moved to hit-to-kill attacks as well. This includes the
MIM-104 Patriot
The MIM-104 Patriot is a mobile interceptor missile surface-to-air missile (SAM) system, the primary such system used by the United States Army and several allied states. It is manufactured by the U.S. defense contractor Raytheon and derives it ...
, whose PAC-3 version removed the warhead and upgraded the
solid fuel rocket motor to produce an interceptor missile that is much smaller overall, as well as the
RIM-161 Standard Missile 3, which is dedicated to the anti-missile role.
Delivery
Some kinetic weapons for targeting objects in
spaceflight
Spaceflight (or space flight) is an application of astronautics to fly objects, usually spacecraft, into or through outer space, either with or without humans on board. Most spaceflight is uncrewed and conducted mainly with spacecraft such ...
are
anti-satellite weapon
Anti-satellite weapons (ASAT) are space weapons designed to incapacitate or destroy satellites for Military strategy, strategic or Military tactics, tactical purposes. Although no ASAT system has been utilized in warfare, a few countries (China, ...
s and
anti-ballistic missile
An anti-ballistic missile (ABM) is a surface-to-air missile designed to Missile defense, destroy in-flight ballistic missiles. They achieve this explosively (chemical or nuclear), or via hit-to-kill Kinetic projectile, kinetic vehicles, which ma ...
s. Since in order to reach an object in orbit it is necessary to attain an extremely high velocity, their released kinetic energy alone is enough to destroy their target; explosives are not necessary. For example: the energy of
TNT
Troponin T (shortened TnT or TropT) is a part of the troponin complex, which are proteins integral to the contraction of skeletal and heart muscles. They are expressed in skeletal and cardiac myocytes. Troponin T binds to tropomyosin and helps ...
is 4.6 MJ/kg, and the energy of a kinetic kill vehicle with a closing speed of is 50 MJ/kg. For comparison, 50MJ is equivalent to the kinetic energy of a
school bus
A school bus is any type of bus owned, leased, contracted to, or operated by a school or school district. It is regularly used to Student transport, transport students to and from school or school-related activities, but not including a charter ...
weighing 5 metric tons, traveling at . This saves costly weight and there is no
detonation
Detonation () is a type of combustion involving a supersonic exothermic front accelerating through a medium that eventually drives a shock front propagating directly in front of it. Detonations propagate supersonically through shock waves with ...
to be precisely timed. This method, however, requires direct contact with the target, which requires a more accurate
trajectory
A trajectory or flight path is the path that an object with mass in motion follows through space as a function of time. In classical mechanics, a trajectory is defined by Hamiltonian mechanics via canonical coordinates; hence, a complete tra ...
. Some
hit-to-kill
A kinetic energy weapon (also known as kinetic weapon, kinetic energy warhead, kinetic warhead, kinetic projectile, kinetic kill vehicle) is a projectile weapon based solely on a projectile's kinetic energy to inflict damage to a target, inst ...
warheads are additionally equipped with an explosive directional warhead to enhance the kill probability (e.g. Israeli
Arrow
An arrow is a fin-stabilized projectile launched by a bow. A typical arrow usually consists of a long, stiff, straight shaft with a weighty (and usually sharp and pointed) arrowhead attached to the front end, multiple fin-like stabilizers c ...
missile or U.S.
Patriot PAC-3).
With regard to anti-missile weapons, the
Arrow missile and
MIM-104 Patriot PAC-2 have explosives, while the
Kinetic Energy Interceptor
The Kinetic Energy Interceptor (KEI) was a planned U.S. missile defense program whose goal was to design, develop, and deploy kinetic energy-based, mobile, ground and sea-launched missiles that could intercept and destroy enemy ballistic missiles ...
(KEI),
Lightweight Exo-Atmospheric Projectile
The Lightweight Exo-atmospheric Projectile (LEAP) is a lightweight miniaturized kinetic kill vehicle designed to destroy incoming ballistic missiles both inside and outside the Earth's atmosphere.Paul Baker, Buster Kelley, Anne Avetissian, ''Li ...
(LEAP, used in
Aegis BMDS), and
THAAD
Terminal High Altitude Area Defense (THAAD), formerly Theater High Altitude Area Defense, is an American anti-ballistic missile defense system designed to intercept and destroy short-, medium-, and intermediate-range ballistic missiles in th ...
do not (see
Missile Defense Agency
The Missile Defense Agency (MDA) is a component of the Federal government of the United States, United States government's United States Department of Defense, Department of Defense responsible for developing a comprehensive Missile defense, defe ...
).
A kinetic projectile can also be dropped from aircraft. This is applied by replacing the explosives of a regular bomb with a non-explosive material (e.g. concrete), for a precision hit with less
collateral damage
"Collateral damage" is a term for any incidental and undesired death, injury or other damage inflicted, especially on civilians, as the result of an activity. Originally coined to describe military operations, it is now also used in non-milit ...
; these are called
concrete bombs. A typical bomb has a mass of and a speed of impact of . It is also applied for training the act of dropping a bomb with explosives. This method has been used in
Operation Iraqi Freedom
The Iraq War (), also referred to as the Second Gulf War, was a prolonged conflict in Iraq lasting from 2003 to 2011. It began with the invasion by a United States-led coalition, which resulted in the overthrow of the Ba'athist governm ...
and the subsequent military operations in
Iraq
Iraq, officially the Republic of Iraq, is a country in West Asia. It is bordered by Saudi Arabia to Iraq–Saudi Arabia border, the south, Turkey to Iraq–Turkey border, the north, Iran to Iran–Iraq border, the east, the Persian Gulf and ...
by mating concrete-filled training bombs with
JDAM
The Joint Direct Attack Munition (JDAM) is a guidance kit that converts unguided bombs, or "dumb bombs", into all-weather precision-guided munitions (PGMs). JDAM-equipped bombs are guided by an integrated inertial guidance system coupled to a Gl ...
GPS
The Global Positioning System (GPS) is a satellite-based hyperbolic navigation system owned by the United States Space Force and operated by Mission Delta 31. It is one of the global navigation satellite systems (GNSS) that provide geol ...
guidance kits, to attack vehicles and other relatively "soft" targets located too close to civilian structures for the use of conventional
high explosive
An explosive (or explosive material) is a reactive substance that contains a great amount of potential energy that can produce an explosion if released suddenly, usually accompanied by the production of light, heat, sound, and pressure. An exp ...
bombs.
Divert and attitude control
When targeting objects in spaceflight, the final part of the kinetic vehicle's travel occurs in thin atmosphere or the near-vacuum of space. As a result, aerodynamic surfaces will have little use in course-correction, and rocket thrusters need to be used. The basic paradigm used for this purpose is a ''divert and attitude control system'' (DACS), with four divert thrusters and six attitude control nozzles attached to the KV. This kind of design is found in many anti-missile and anti-satellite weapons, including the
RIM-161 Standard Missile 3 and THAAD. An common design uses a DACS driven by a
solid fuel
Solid fuel refers to various forms of solid material that can be burnt to release energy, providing heat and light through the process of combustion. Solid fuels can be contrasted with liquid fuels and gaseous fuels. Common examples of solid fu ...
gas generator
A gas generator is a device for generating gas. A gas generator may create gas by a chemical reaction or from a solid or liquid source, when storing a pressurized gas is undesirable or impractical.
The term often refers to a device that uses a ...
, with the gas then distributed among the thrusters and nozzles as required for intercept. Neutral coasting is achieved by making the thrusters cancel each other out. The gas generator can be made throttle-able and/or re-ignitable.
Advantages and disadvantages
The primary advantage kinetic energy weapons is that they minimize the launch mass of the weapon, as no weight has to be set aside for a separate warhead. Every part of the weapon, including the airframe, electronics and even the unburned maneuvering fuel contributes to the destruction of the target. Lowering the total mass of the vehicle offers advantages in terms of the required
launch vehicle
A launch vehicle is typically a rocket-powered vehicle designed to carry a payload (a crewed spacecraft or satellites) from Earth's surface or lower atmosphere to outer space. The most common form is the ballistic missile-shaped multistage ...
needed to reach the required performance, and also reduces the mass that needs to be accelerated during maneuvering.
Another advantage of kinetic energy weapons is that any impact will almost certainly guarantee the destruction of the target. In contrast, a weapon using a
blast fragmentation warhead will produce a large cloud of small fragments that will not cause as much destruction on impact. Both will produce effects that can easily be seen at long distance using
radar
Radar is a system that uses radio waves to determine the distance ('' ranging''), direction ( azimuth and elevation angles), and radial velocity of objects relative to the site. It is a radiodetermination method used to detect and track ...
or
infrared
Infrared (IR; sometimes called infrared light) is electromagnetic radiation (EMR) with wavelengths longer than that of visible light but shorter than microwaves. The infrared spectral band begins with the waves that are just longer than those ...
detectors, but such a signal will generally indicate complete destruction in the case of a kinetic energy weapon while the fragmentation case does not guarantee a "kill".
No chemical munitions in the weapons also means that there is far less pollution of an area from a kinetic weapon.
The main disadvantage of the kinetic energy weapons is that they require extremely high accuracy in the guidance system, on the order of .
See also
*
*
*
*
Explanatory notes
References
Bibliography
*
*{{cite web , title= Kinetic Energy Hit-To-Kill Warhead , url=https://www.globalsecurity.org/space/systems/kew-htk.htm , publisher=
GlobalSecurity.org
GlobalSecurity.org is an American independent, nonpartisan, nonprofit organization that serves as a think tank, and research and consultancy group.
Focus
The site is focused on national and international security issues; military analysis, sys ...
, ref=CITEREFGlobalSecurity
External links
Anti-ballistic missiles
Projectiles
Collision