The M-270 Multiple Launch Rocket System, also known as the MLRS, is a rocket artillery
system originally fielded by the U.S. Army
in 1983. It complements traditional tube arty by providing fast-response wide area fires on demand. The system itself is housed in what is called the SPLL, for Self-Propelled Launcher/Loader vehicle. This is a turbodiesel
-powered tracked vehicle, lightly armored, which contains an elevating/traversing canister launch system on its back. When performing fires, the vehicle stops, elevates the rear canisters (which are stored horizontally for transport) and fires from one or both of its two canisters.
The canisters themselves can contain a variety of munitions from what are known as the 'MFOM' or MLRS Family of Munitions. The U.S. military likes using the word 'family' to describe similar weapon systems - see FASCAM for another example. In any case, the primary munitions fired are either the M26 rocket, which is an unguided rocket with a DPICM submunition payload, or the ATACMS guided ballistic missile. Each canister can hold either six M26 rockets or one ATACMS. The MLRS can fire a 'ripple' of all 12 M26 rockets from a full loadout in under one minute; it can be loaded, trained, elevated and fired in under five minutes. The MLRS contains a highly automated fire control system, which allows a small crew (3 men normally, but even a single soldier can operate it in a pinch, including reloading using the built-in crane) to carry out firing operations. The system was designed to improve survivability by reducing the amount of time which the launcher has to spend in a single position. For fire missions, the central headquarters system (AFATDS, usually) can send data for the mission directly to the MLRS fire control system. The FCS notifies the crew to stop the vehicle, and when that has been done, the system can then elevate, traverse and fire the mission autonomously, returning to carry position when done. Typically, this sequence (not including loading) can be carried out in under one or two minutes. Newer versions of the SPLL have improved machinery, reducing the amount of time it takes to elevate and train the launch canister significantly in order to reduce time spent stationary.
First fired in anger during Operation Desert Shield, the MLRS was deemed highly effective. Using DPICM submunitions, a single MLRS fire mission of 12 rockets can effectively blanket an entire 1 km military map 'grid square' with explosives in under a minute. The DPICM means that the submunitions are moderately effective against vehicles as well as personnel; a well-placed DPICM hit can disable or destroy a soft-skinned vehicle. A single M26 rocket contains 644 submunitions (each of which is roughly a small grenade); later, longer-ranged rockets contain between 400 and 500. Newer variants of these rockets are being tested which sport GPS guidance and unitary HE warheads. Although the initial maximum range of the M26 was 23 km, newer variants reach out as far as 45km, which is (at present) limited by accuracy in the unguided models. Despite being able to compensate for weather conditions at launch, beyond that range the rockets deviate significantly from their aimpoints.
The ATACMS is longer-ranged and guided, able to carry out relatively precise strikes at longer ranges. Newer variants of the ATACMs can use either submunitions or a unitary warhead, and can be set to drop on their targets nearly vertically in order to properly hit targets occluded by urban or mountainous terrain. They can reach out to 300 km from the launcher, using GPS guidance and reduced payloads from the original 950 submunitions carried on the first version. Submunitions have become politically problematic in recent years, as the phrase 'cluster bomb' has come to evoke images of civilian casualties caused by dud submunitions detonating long after the weapon lands - years, in some cases. As a result, newer variants of both ATACMS and the M26 are able to load unitary warheads which do not leave unexploded submunitions lying about.
The MLRS is nicknamed the 'Grid Square Removal System' by the British Army, due to its enormous area of effect. It is also known as the 'Gypsy Wagon,' since the extremely limited space inside the vehicles cause most crews to lash their personal gear to the top of the launch vehicle - giving it a somewhat ragged appearance. This is a tradition of tankers everywhere.