The fundamental mission of armor and other direct fire weapons is to close with and destroy the enemy. The ability to move, shoot, communicate, and provide armored protection is a decisive factor on the modern battlefield. In accomplishing its assigned missions, armor uses fire, maneuver, and shock effect, synchronized with other maneuver elements and with combat support (CS) and combat service support (CSS) assets. When properly supported, it is capable of conducting sustained operations against any sophisticated threat.
The entire purpose of the tank is to carry the main gun into battle. The armor is provided to ensure that the crew is protected from shrapnel (the main cause of battlefield casualties) and small arms fire. The crew exists solely to serve the main gun. The driver gets the vehicle to firing position, the tank commander selects targets, the loader ensures the weapon is loaded with the correct ammunition for the target selected, and the gunner makes sure the round strikes the target in the area of maximum vulnerability.
Since its inception during the First World War, the tank has been the preeminent system used in maneuver forces. They embody the mobile protected firepower needed to fight the close combat maneuver battle. In the attack, tanks functioning as a part of a combined arms mounted force must enter the close combat battlespace in order to win; driving the enemy from an objective or destroying him. In the defense, mounted units must also fight and destroy enemy forces moving into this battlespace. The operational capabilities of survivability, lethality, and mobility are defined by the need to fight and win against any system entering or engaging tanks in the battlespace. Survivability must be maximized against any weapon system capable of engaging in the close combat battlespace. This includes threat tanks firing KE projectiles, guided and unguided (infantry fired) anti-tank weapons and high precision and conventional artillery delivered munitions. Most threat weapons can be defeated with base armor, but improved ATGMs and new top-attack weapons require armor solutions that would exceed weight limitations. New technologies such as sensors and countermeasure suites and signature management have been shown to greatly enhance survivability against the vast majority of these systems. Lethality requirements are driven by the need for the tank to engage and destroy any vehicle entering the close combat battlespace. Enemy tanks with heavy base armors and sophisticated appliques present the greatest challenge to our tanks. Finally, tanks must be able to maneuver quickly over the battlefield in order to bring our lethality and survivability assets to bear. So far, only fully tracked vehicles can provide load carrying capacity and cross-country mobility needed to effectively fight the maneuver battle.
Tanks offer an impressive array of capabilities on the modern battlefield: excellent cross-country mobility, sophisticated communications, enhanced target acquisition, lethal firepower, and effective armor protection. In combination, these factors produce the shock effect that allows armor units to close with and destroy the enemy in most weather and light conditions. Tanks can move rapidly under a variety of terrain conditions, negotiating soft ground, trenches, small trees, and limited obstacles. In addition, global positioning systems (GPS) and inertial position navigation (POSNAV) systems allow today's tanks to move to virtually any designated location with greater speed and accuracy than ever before. Use of visual signals and the single channel ground/airborne radio system (SINCGARS) facilitates rapid and secure com munication of orders and instructions. This capability allows tank crews to quickly mass the effects of their weapon systems while remaining dispersed to limit the effects of the enemy's weapons. On-board optics and sighting systems enable the crews to acquire and destroy enemy tanks, armored vehicles, and fortifications using the main gun or to use machine guns to suppress enemy positions, personnel, and lightly armored targets. The tank's armor protects crew members from small arms fire, most artillery, and some antiarmor systems.
Tanks require extensive maintenance, proficient operators, and skilled mechanics, as well as daily resupply of large quantities of bulky petroleum products such as fuel, oil, and grease. They are vulnerable to the weapons effects of other tanks, attack helicopters, mines, ATGMs, antitank guns, and close attack aircraft. When tanks operate in urban areas, dense woods, or other close terrain, reduced visibility leaves them vulnerable to dismounted infantry attacks as well. In such situations, they are usually restricted to trails, roads, or streets; this severely limits maneuverability and observation. Existing or reinforcing obstacles can also restrict or stop tank movement.Military theorists generally agree that a defending army could hope for success if the attacking enemy had no greater than a 3:1 advantage in combat power. The best intelligence estimates in the 1970s, however, concluded that the Warsaw Pact armies enjoyed a much larger advantage. Continuing budget constrictions made unlikely the possibility of increasing the size of the American military to match Soviet growth. To solve the problem of how to fight an enemy that would almost certainly be larger, the United States relied, in part, on technologically superior hardware that could defeat an enemy at ratios higher than 1:3. To achieve that end, the Army in the early 1970s began work on the "big five" equipment systems: a new tank, a new infantry combat vehicle, a new attack helicopter, a new transport helicopter, and a new antiaircraft missile.
Several factors affected new equipment design. Although the big five equipment originated in the years before AirLand Battle doctrine was first enunciated, that doctrine quickly had its effect on design criteria. Other factors were speed, survivability, and good communications, which were essential to economize on small forces and give them the advantages they required to defeat larger, but presumably more ponderous, enemies. Target acquisition and fire control were equally important, since the success of a numerically inferior force really depended on the ability to score first-round hits. Such simply stated criteria were not easy to achieve, and all of the weapon programs suffered through years of mounting costs and production delays. A debate that was at once philosophical and fiscal raged around the new equipment, with some critics preferring simpler and cheaper machines, fielded in greater quantities. The Department of Defense persevered, however, in its preference for technologically superior systems and managed to retain funding for most of the proposed new weapons. Weapon systems were expensive, but defense analysts recognized that personnel costs were even higher and pointed out that the services could not afford the manpower to operate increased numbers of simpler weapons. Nevertheless, spectacular procurement failures, such as the Sergeant York division air defense gun, kept the issue before the public, and such cases kept program funding for other equally complex weapons on the agenda for debate.' The first of the big five systems, the M1 Abrams tank, weathered considerable criticism and, in fact, began from the failure of a preceding tank program. The standard tanks in the Army inventory had been various models of the M48 and M60, both surpassed in some respects by new Soviet equipment. The XM803 was the successor to an abortive joint American-German Main Battle Tank-70 project and was intended to modernize the armored force. Concerned about expense, Congress withdrew funding for the XM803 in December 1971, thereby canceling the program, but agreed to leave the remaining surplus of $20 million in Army hands to continue conceptual studies. For a time, designers considered arming tanks with missiles for long-range engagements. This innovation worked only moderately well in the M60A2 main battle tank and the M551 Sheridan armored reconnaissance vehicle, both of which were armed with the MGM51 Shillelagh gun launcher system. In the late 1960s, however, tank guns were rejuvenated by new technical developments that included a fin-stabilized, very high velocity projectile that used long-rod kinetic energy penetrators. Attention centered on 105-mm. and 120-mm. guns as the main armament of any new tank. Armored protection was also an issue of tank modernization. The proliferation of antitank missiles that could be launched by dismounted infantry and mounted on helicopters and on all classes of vehicles demonstrated the need for considerable improvement. At the same time, weight was an important consideration because the speed and agility of the tank would be important determinants of its tactical utility. No less important was crew survivability; even if the tank were damaged in battle, it was important that a trained tank crew have a reasonable chance of surviving to man a new vehicle. The Army made the decision for a new tank series in 1972 and awarded developmental contracts in 1973. The first prototypes of the M1, known as the XM1, reached the testing stage in 1976, and the tank began to arrive in battalions in February 1980. The M1 enjoyed a low silhouette and a very high speed, thanks to an unfortunately voracious gas turbine engine. Chobham spaced armor (ceramic blocks set in resin between layers of conventional armor) resolved the problem of protection versus mobility. A sophisticated fire control system provided main gun stabilization for shooting on the move and a precise laser range finder, thermal-imaging night sights, and a digital ballistic computer solved the gunnery problem, thus maximizing the utility of the 105-mm. main gun. Assembly plants had manufactured more than 2,300 of the 62-ton M1 tank by January 1985, when the new version, the MlA1, was approved for full production. The MlA1 had improved armor and a 120mm. main gun that had increased range and kill probability. By the summer of 1990 several variations of the M1 had replaced the M60 in the active force and in a number of Army Reserve and National Guard battalions. Tankers had trained with the Abrams long enough to have confidence in it. In fact, many believed it was the first American tank since World War II that was qualitatively superior to Soviet models. The second of the big five systems was the companion vehicle to the Abrams tank: the M2 Bradley infantry fighting vehicle, also produced in a cavalry fighting version as the M3. Its predecessor, the M113 armored personnel carrier, dated back to the early 1960s and was really little more than a battle taxi. The 1973 Arab-Israeli War demonstrated that infantry should accompany tanks, but it was increasingly clear that the M113 could not perform that function because it was far slower than the M1, its obsolescence aside. European practice also influenced American plans for a new vehicle. German infantry used the well-armored Marder, a vehicle that carried seven infantrymen in addition to its crew of three, was armed with a 20-mm. gun and coaxial 7.62-mm. machine gun in a turret, and allowed the infantrymen to fight from within the vehicle. The French Army fielded a similar infantry vehicle in the AMX-1OP in 1973. The Soviets had their BMP-ls, which had a 73-mm. smoothbore cannon and an antitank guided missile, as early as the late 1960s. Variations of the BMP were generally considered the best infantry fighting vehicles in the world during the 1980s. The United States had fallen at least a decade behind in the development of infantry vehicles. General DePuy and General Starry, who at that time commanded the U.S. Army Armor Center and School at Fort Knox, Kentucky, agreed the Army needed a new infantry vehicle and began studies in that direction. In 1980, when Congress restored funding to the Infantry Fighting Vehicle Program, the Army let contracts for prototypes, receiving the first production models the next year. Like the Abrams, the Bradley was a compromise among competing demands for mobility, armor protection, firepower, and dismounted infantry strength. As produced, the vehicle was thirty tons, but carried a 25-mm. cannon and 7.62-mm. coaxial machine gun to allow it to fight as a scout vehicle and a TOW (tube launched, optically tracked, wire command-link guided) missile launcher that enhanced the infantry battalion's antiarmor capability. The vehicle's interior was too small for the standard rifle squad of nine: it carried six or seven riflemen, depending on the model. That limitation led to discussions about using the vehicle as the "base of fire" element and to consequent revisions of tactical doctrine for maneuver. Critical to its usefulness in the combined arms team, however, the Bradley could keep up with the Abrams tank. By 1990 forty-seven battalions and squadrons of the Regular Army and four Army National Guard battalions had M2 and M3 Bradleys. A continuing modernization program that began in 1987 gave the vehicles, redesignated the M2A1 and M3A1, the improved TOW 2 missile. Various redesigns to increase survivability of the Bradley began production in May 1988, with these most recent models designated the A233.