Missile System

A missile is an intelligent unmanned rocket designed to carry the payload to a designated point with an aim of destroying the object/target. The missile is designed keeping in mind its target, trajectory, warhead, range, velocity and launch platform.

Missile vs Rocket
A powered, guided munition that travels through the air or space known as a missile (or guided missile). A powered, unguided munition is known as a rocket. Unpowered munitions not fired from a gun are called bombs whether guided or not; unpowered, guided munitions are known as guided bombs or smart bombs.

How does Missile Work?
• Propulsion System – The propulsion system in a missile is required to achieve terminal conditions like range, speed and warhead carrying capability. The missile is propelled either by rockets or jet engines using solid or liquid fuel. Some missiles use hybrid technology for propelling it to its intended point.

• Guidance System – The function of the guidance system is to maintain the missile in its desired flight path by using altitude control mechanism. This is done by controlling the pitch, roll and yaw of the weapon. The guidance system operates as an auto­pilot, damping out fluctuations that tend to deflect the missile from its intended flight path.In some missiles, the guidance commands are generated internally by the missile’s computer. In others, the commands are transmitted to the weapon by some external source.The guidance for the missiles is provided by GPS, Inertial guidance system, lasers, TV, Infra-red and radar. Sometimes a combination of two or more systems can be used to provide precision guidance and targeting to the missile.

• Aerodynamics Features – The aerodynamic features of a missile, also called Cont Rolling Surf Aces, are used to control the Missile’s Flight. The fins, wings and tail are the three major aerodynamic control surf aces used to steer the missile. The missile’s course can be altered by moving these controlling surfaces.

• Terminal Guidance – In case of precision weapons, the target seeker comes into picture when the missile starts detecting its target. The mechanism also works to determine the time of activating the warhead. After finding out the target, the device sends an electrical impulse to trigger the activation system. The target seeker is based either on radar or Infra­Red (IR) or laser devices.

• Warhead – The warhead of a missile is selected keeping in mind its target type. It inflicts damage on the target and hence determines the missile’s let hality. An optimum position of burst is used to achieve the desired effect on the target limits – the closer the burst to the target, the smaller the warhead needed.In other cases where the missile is required to cause destruction on hard targets, before detonation of warhead, penetration is achieved by employing a variety of technologies.

Propulsion Systems
• Solid Propulsion: Solid fuel is used in solid propulsion. Generally, the fuel is aluminium powder. Solid propulsion has the advantage of being easily stored and can be handled in fuelled condition. It can reach very high speeds quickly. Its simplicity also makes it a good choice whenever large amount of thrust is needed.

• Liquid Propulsion: The liquid propulsion technology uses liquid as fuel. The fuels are hydrocarbons. The storage of missile with liquid fuel is difficult and complex. In addition, preparation of missile takes considerable time. In liquid propulsion, propulsion can be controlled easily by restricting the fuel flow by using valves and it can also be controlled even under emergency conditions. Basically, liquid fuel gives high specific impulse as compared to solid fuel.

• Hybrid Propulsion: There are 2 stages in hybrid propulsion ­ solid propulsion and liquid propulsion. This kind of propulsion compensates the disadvantages of both propulsion systems and has the combined advantages of the 2 propulsion systems.

• Ramjet: A Ramjet engine does not have any turbines unlike turbojet engines. It achieves compression of intake air just by the forward speed of the air vehicle. The fuel is injected and ignited. The expansion of hot gases after fuel injection and combustion accelerates the exhaust air to a velocity higher than that at the inlet and creates positive push. However, the air entering the engine should be at supersonic speeds. So, the aerial vehicle must be moving in supersonic speeds. Ramjet engines cannot propel an aerial vehicle from zero to supersonic speeds.

• Scramjet: Scramjet is an acronym for Supersonic Combustion Ramjet. The difference between Scramjet and Ramjet is that the combustion takes place at supersonic air velocities through the engine. It is mechanically simple, but vastly more complex aerodynamically than a jet engine. Hydrogen is normally the fuel used.

• Cryogenic: Cryogenic propellants are liquefied gases stored at very low temperatures, most frequently liquid hydrogen as the fuel and liquid oxygen as the oxidizer. Cryogenic propellants require special insulated containers and vents which allow gas to escape from the evaporating liquids. The liquid fuel and oxidizer are pumped from the storage tanks to an expansion chamber and injected into the combustion chamber where they are mixed and ignited by a flame or spark. The fuel expands as it burns and the hot exhaust gases are directed out of the nozzle to provide thrust.

Launch Platforms
• Aircraft
• Ground Vehicles
• Ships
• Submarines

Speed
• SUBSONIC – speed less than that of sound.
• SUPERSONIC – speed greater than that of sound.
• HYPERSONIC – speeds of more than five times the speed of sound (Mach 5).

Stealth Technology
• Stealth technology also termed LO technology (low observable technology) is a sub-discipline of military tactics and passive electronic countermeasures, which cover a range of techniques used with personnel, aircraft, ships, submarines, missiles and satellites to make them less visible to radar, infrared,sonar and other detection methods. It corresponds to military camouflage for these parts of the electromagnetic spectrum (Multi-spectral camouflage).

• In simple terms, stealth technology allows an object to be partially invisible to Radar or any other means of detection. This doesn’t allow the object to be fully invisible on radar. All it can do is to reduce the detection range or an object or enemy platform. This is similar to the camouflage tactics used by soldiers in jungle warfare. Unless the soldier comes near you, you can’t see him. Though this gives a clear and safe striking distance for the objects using it, there is still a threat from radar systems, which can detect stealth platforms.