The MLR or MLRS is a type of rocket artillery system, with the rockets having capabilities different from the artillery; like longer range and different payloads, considerably larger warheads than a similarly sized artillery platform or multiple warheads. Since unguided rocket artillery is inaccurate and slow to reload compared to artillery, multiple rockets are combined in MLR that can launch multiple rockets simultaneously. Modern rockets can use GPS or inertial guidance to combine the advantages of rockets with high accuracy.

The British learnt advanced rocketry from India. The Mysore Army used indigenous iron-cased rockets effectively against the British East India Company during 1780s and 1790s. Europe was also developing rocketry but their rockets were not iron-cased. Having adopted Mysorean Rockets, European armies developed explosive steel-cased bombardment rockets with minimal launchers. European navies developed naval multiple launcher mounts with steadily improving explosive rockets for light and coastal vessels. These weapons were largely replaced by conventional light artillery during the late nineteenth century.

Modern Era

Modern MLR systems use modern land navigation like GPS for quick and accurate positioning. MLR systems with GPS can have their MLRS dispersed and fire from dispersed positions at a single target. Radar can track weather balloons to determine winds or to track special rockets which selfdestruct in the air. Such tracking radars can also be used to predict the range error of individual rockets. A more sophisticated system makes use of radar data and oneway radio data-link to initiate a two dimensional (range and azimuth) correction of the rocket’s flight-path with steering by fins or nose thrusters. The latter is more common with systems which can be used to upgrade old rockets.

MLRS remain in uses though they still can’t fully engage enemy deployed in reverse slopes of mountains, compared to howitzers which can improve accuracy by adding or removing propellant increments. For reducing the long minimum firing range of MLRs, drag rings are being added to the nose of the rockets. This increased drag slows the rocket down resulting in less flat trajectory. However, only some MLR with individuallyloaded rockets offer have this option; prepackaged MLR munitions such as those for MLRS do not offer this option. Some countries have improvised MLRS based on helicopter- or aircraft-mounted rocket pods (typically 57–80mm).

Fin-stabilised rockets allow for easy course corrections using rudders or minute charges. Guided munitions have been introduced to exploit this. Guidance principles such as GPS satellite navigation, inertial navigation systems and semi-active laser seekers are used for this. This improves dispersion from a CEP of hundreds of metres at dozens of kilometres range to just a few metres. Long range MLR missiles often fly a higher quasi-ballistic trajectory than shorter ranged rockets and thus pose a deconfliction challenge, as they might collide with friendly aircraft in the air.

Under the Convention on Cluster Munitions, only large sub-munitions, smoke agents, and unitary high explosive warheads are permitted, not other cluster munitions for MLRS. Some examples of these are the SMArt, 155, 155 Bonus and SADARM, which use relatively large Explosively Formed Projectile (EFP) warheads with sensors (millimeter wave radar, infrared) which search the ground for tanks to attack in a spiral pattern during their descent (retarded by parachutes).

China and Pakistan

China’s WS-2 is a 400mm guided MLRS (Multiple Launch Rocket System) designed and manufactured by China. It is an advanced rocket system characterised by long-range fast response, with easy operation and maintenance. The WS-2 adopts simple control technology, which increases the accuracy with low costs. The rocket launcher system is mounted at the rear of a 6x6 truck chassis with three tubes in two lines, and has an elevation range. Manual controls are also provided. In firing position, four stabilisers are lowered to the ground hydraulically to provide more suitable firing platform. One of these is mounted at the rear of the chassis. The system can operate up to a maximum height of 3,500 metre above sea level and in ambient temperatures from -40 degree to +55 degree centigrade, and with relative humidity of up to 75 per cent at 15 degrees centigrade. The rockets are fired from containers. The WS-2 has a preparation time of less than 12 minutes.

Since initial development of WS-2, advanced versions have been developed: WS-1 with maximum range of 100 km; WS-1B with maximum range of 180 km; WS-2B – upgraded version with long range capacity; WS-2C – upgraded version with GPS guidance and 350 km range; WS-2D - upgraded version with GPS guidance, 400 km range and ability to launch lethal unmanned aerial vehicles.

China’s Academy of Launch Vehicle Technology (CALT), also known as 1st Space Academy, too has developed A-100, a 300mm 10-tube MLR for PLA ground forces. It is a simple derivative of Weishi Rockets WS-1 with simple cascade terminal inertial guidance. The A-100 has a firing range of 40~100 km. The A-100 rocket is 7.3m in length, weighs 840 kg, carries a 235 kg warhead, and is spin stabilised through stabilising fins. It is fitted with a warhead containing 500 HE-FRAG (High Explosive Fragmentation) anti-armour/personnel sub-munitions. The sub-munition can penetrate 50mm of armour, and has a blast radius of 7m. The sub-munitions have a spreading radius of 100 +/- 40 metres. The rocket motor is a single chamber, solid rocket motor with an advanced hydroxy-terminated polybutadiene (HTPB) composition rocket propellant. The rocket is equipped with an onboard computer to help correct the horizontal and vertical deviations. During the first three seconds of the rocket’s flight, the onboard computer detects the horizontal difference between the programmed trajectory and actual status of the rocket, and controls the rocket’s stabilising thrust system to correct the rocket’s flying direction. The onboard computer corrects the vertical deviation by adjusting the warhead detonation time so that the sub-munitions are spread with high accuracy.

Under the Convention on Cluster Munitions, only large sub-munitions, smoke agents, and unitary high explosive warheads are permitted, not other cluster munitions for MLRS

The A-100 launch vehicle is based on a TAS5380 8x8 wheeled truck chassis. It has a range of 650 km and reloading time of 20 minutes. The vehicle is equipped with four hydraulically operated stabilisers which are lowered in preparation for the rocket launch. 10 launcher tubes mounted on the chassis are arranged as two blocks of four (top) and six (bottom) tubes. Two variants of the A100 have been developed in the A200 and A300. These are updated version of the A100 which has simple cascade inertial terminal guidance updated by GPS. The arrangement of A200 is different from A100 in that each launching box consists of three rows of launching tubes, three on the top and bottom respectively, and two in the middle. A200 rockets also have additional forward control surfaces that were not present on A100 rockets. The A300 has a range of 290 km and integrated with GNS/INS guidance. The Pakistan army has 450 plus Chinese A100 systems, mostly produced in Pakistan under its Space and Upper Atmosphere Research Commission (SUPARCO).

India

In 2017, Indian Army (IA) had 62xBM-30 Smerch systems. Since, 2012, India’s Ordnance Factory Board has produces several rocket variants for the system which has a strike range of 70 to 90 km. Each Smerch battery has six launch vehicles. Indian Army’s 9K58 Smerch 300mm multiple launcher rocket (MLR) systems are being mounted on 81 indigenously designed 10x10 high-mobility vehicles developed by Ashok Leyland. The vehicle, which is fitted with a hydraulic crane to reload the system, will supplement and eventually replace the 9A52-2 launch vehicles based on the MAZ-543M 8x8 truck chassis.

The Indian Army also operates the Russian BM-21 Grad launchers. In 2016, India had 150 BM-21 Grad/LRARs. The BM-21 Grad is a Russian origin truckmounted 122mm MLR. BM-21 Grad is mounted on 6x6 army trucks. All 40 rockets of BM-21 Grad can be away in as little as 20 seconds, but can also be fired individually or in small groups in severalsecond intervals.

Pinaka is a multi launch rocket system (MLRS) used by the Indian Army. It was developed by the Defence Research and Development Organisation (DRDO) to replace the BM-21 Grad multiple rocket launcher systems of the Indian Army. It is a multifaceted system integrating high energy propulsion, sub-munition warheads, servo-controlled launcher configuration and fire control computer. The Pinaka system is based on the 8x8 vehicle. Each battery is composed of six launcher vehicles, six loader-cum replenishment vehicles and two command post vehicles. Each launcher vehicle carries two pods, housing a total of 12 rockets. Each Pinaka rocket is capable of carrying a 100 kg payload for a range of 40 km. A single Pinaka battery can neutralise a surface area of 700m x 500m. The combat capabilities of Pinaka MLRS were tested during the Kargil war in June 1999. The maiden Pinaka MLRS regiment was set up in February 2000.