A little bit of engineering (562404), страница 22
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The ballistic missile threat was the most important development in defense systems. When the first German V-2 ballistic missiles arced over England on September 6, 1944, a new day in warfare dawned. The V-2 traveled at supersonic speeds and was impossible to intercept. After World War II an immediate missile race began between the United States and the Union of Soviet Socialist Republics (USSR). The goal was to build upon German technology and create a long-range intercontinental ballistic missile, or ICBM, that could deliver a nuclear warhead.
| A | Deterrence |
By 1958, both the United States and the USSR had successfully tested ICBMs and immediately began to improve them. As a result, both nations became extremely vulnerable to attack. The amount of warning that existing national radar systems could give for an incoming bomber attack had been measured in hours, but an ICBM could loft from a launching base in the USSR and impact in the United States within 30 minutes. There were no technical means to stop a missile once launched, so national leaders turned to the idea of deterrence.
Deterrence uses the threat of an offensive attack as a defense—or deterrent—against such an attack. The USSR, with their initial lead in rocket and missile technology, had adopted a so-called first strike strategy. The Soviet leaders recognized that an exchange of nuclear missiles would be so devastating to both countries that the USSR had to launch its missiles first, and in such numbers that a crippled United States would not be able to mount a significant retaliatory strike. The United States publicly said it would never undertake a first strike, deciding instead to develop a second-strike capability of such magnitude that no Soviet first strike would avoid retaliation. This strategy became known as mutually assured destruction, which had the appropriate acronym MAD. The arms buildup between the United States and the USSR, and the tensions surrounding the buildup, became known as the Cold War (because no direct combat took place). Although the world came close to nuclear war on several occasions (see Cuban Missile Crisis), the USSR never dared to launch a first strike, so the United States never had to retaliate.
| B | Defense Systems of Other Countries |
Although the Cold War ended in the early 1990s, major military powers continue to employ some version of offensive deterrent and defensive warning capability. Shortly after World War II, political and military alliances were created to offer mutual defense. The United States, Britain, France, and several other countries formed the North Atlantic Treaty Organization (NATO), while the USSR and its satellite countries responded with the Warsaw Pact. Practically all countries monitor their own airspace, but for strategic defense the members of these alliances generally looked to either the United States or the USSR for protection.
| III | OFFENSIVE DETERRENTS |
Several countries such as the United States, Russia, Britain, France and China maintain a force of offensive nuclear weapons to deter against a nuclear attack. The offensive capability of the United States rests on what is known as the Nuclear Triad, comprised of strategic bombers, land-based ICBMs, and submarine-launched ballistic missiles. It was devised so if any one of the three “legs” is destroyed by an attack, the other two can still function. The nuclear powers of the world maintain some or all of these forces.
| A | Bombers |
The United States had initially (from 1945 through about 1960) depended upon the bomber aircraft of the Strategic Air Command (SAC) to deter an attack from the USSR. In the early years of SAC, these aircraft included the Boeing B-50 and the Consolidated B-36. Later jets such as the Boeing B-47 Stratojet and Boeing B-52 Stratofortress jet bombers were faster and could carry more payload. The United States currently maintains B-52, Rockwell B-1B, and Northrop Grumman B-2 bombers capable of being armed with nuclear weapons as part of its strategic force.
| B | ICBMs |
The USSR began an intensive ICBM development program after World War II, and the United States responded in kind. While the Soviet bomber fleet never approached that of the United States in size or capability, the Soviet ICBM fleet was truly formidable. The USSR developed greater numbers of ICBMs than the United States, and these had larger warheads, greater range and superior accuracy to U.S. weapons. The USSR also was successful in hardening (or making resistant to a nuclear attack) its silo launch facilities to a far greater degree than the United States was able to do.
| C | SLBMs |
A similar process followed for the submarine-launched ballistic missile (SLBM), when in the late 1950s the USSR built several submarines able to carry the SS-N-4 Sark missile. In 1960 the United States sent the USS George Washington on patrol, carrying Polaris SLBMs. As technology improved, the SLBM assumed greater importance. A ballistic missile submarine is difficult to detect, can remain on duty for weeks at a time without surfacing, and can fire its missiles from beneath the water’s surface.
| D | Coordination and Command |
The U.S. Strategic Command monitors defense information from various sources and would coordinate a military response to a nuclear attack. The Strategic Air Command (SAC) was for many years the primary deterrent force. It has been replaced in part by the Air Combat Command. For many years as much as 50 percent of the SAC bomber fleet was on airborne alert, armed with nuclear weapons, and able to attack immediately upon notice.
In the event of an attack, U.S. Strategic Command would collect data and present recommendations to the U.S. president and senior advisers (referred to as the National Command Authority). Only the president can make the decision to use nuclear weapons, even in response to an attack. The plan a president would use to respond to an attack is called the Single Integrated Operational Plan, or SIOP. The SIOP consists of several planned responses to various nuclear scenarios. If the President were to decide to use nuclear weapons, several procedures and code phrases would be used to verify the President’s authority. When the procedures are completed, they would authorize the military to use nuclear weapons. Numerous precautions exist in this process to prevent accidental or unauthorized use of nuclear weapons.
The president and the rest of the National Command Authority would possibly give orders from a modified Boeing 747 called a National Airborne Operations Center (NAOC). By being airborne, command authority is less vulnerable to a ground attack. These airplanes are outfitted with advanced communications equipment so the president can stay in contact with U.S. Strategic Command at all times. U.S. Strategic Command also has a number of airborne command centers that can coordinate military forces in the event that ground centers have been destroyed or damaged.
| IV | DEFENSIVE WARNING SYSTEMS |
The consequences of a nuclear exchange would be devastating, with casualties estimated to be in the hundreds of millions on both sides and massive damage to the environment. Both the USSR and the United States were aware of the catastrophic scale of a nuclear exchange, and both built elaborate defensive systems to detect an incoming nuclear attack.
| A | Radar Networks |
From 1949 (when the USSR developed nuclear weapons) to 1959 (when ICBMs became operational), the main strategic threat was bombers. To provide advance warning, several radar posts were built across Canada by joint cooperation between Canada and the United States. The first series of linked radar stations was called the Pinetree Line, established in 1954. Two more lines, the Mid-Canada Line and the Distant Early Warning Line (or DEW Line) were created for more complete radar coverage. The DEW Line, comprising 60 radar sites along the 70th parallel, became operational in 1957.
To warn against ICBMs, the Ballistic Missile Early Warning System (BMEWS) was introduced in 1962. It consists of sophisticated radar sites in Greenland, Alaska, and England. These sites could detect, track and predict impact points of both intercontinental ballistic missiles and smaller intermediate range ballistic missiles (IRBMs) launched from within the USSR. A typical site has four giant scanner search radars, each 50.3 m (165 ft) high and 122 m (400 ft) long; and one tracking radar, a 25.6 m (84 ft) antenna in a 42.6 m (140 ft) diameter housing. The purpose of the BMEWS is to provide sufficient warning time for U.S. bombers to get airborne and ICBM forces to prepare for a counterstrike.
BMEWS is backed up by the Perimeter Acquisition Radar Characterization (PARCS) system. Operating in the U.S. interior, PARCS can detect air traffic over Canada. Four other radar sites monitor the Atlantic and Pacific oceans for possible submarine attacks. These various stations are connected to the North American Aerospace Defense Command (NORAD), to U.S. Strategic Command headquarters, the Pentagon, and to the Canadian Royal Air Force fighter command.
| B | NORAD |
NORAD was activated in 1957 to provide an integrated command for the air defense of the United States and Canada, and to process the information gathered from various radar sites. The reality of ICBMs required the establishment of a detection and tracking system, and the housing of NORAD in a bombproof site located within the interior of Cheyenne Mountain near Colorado Springs, Colorado. With its increased responsibility, NORAD equipment was expanded to include the Airborne Warning and Control Aircraft (AWACS), Over the Horizon (OTH) radar that warns against low-altitude cruise missiles, and a network of satellites. The DEW Line was replaced with a superior system called the North Warning System; and the Joint Surveillance System (JSS), operated by the U.S. Air Force and the Federal Aviation Administration, provides additional air traffic coverage. NORAD monitors all of these early warning systems, processes the information, and then relates it to U.S. Strategic Command.
| C | Soviet Air Defense |
The USSR built an even more extensive integrated air defense system, covering the country with radar systems, surface-to-air missile sites and large numbers of interceptors (fast military aircraft designed to destroy attacking airplanes). The USSR built a huge infrastructure of civil and military defense systems, including deep underground blast shelters for the country’s leaders and key industries. Russia continues to maintain this network. The United States has abandoned its rather primitive civil defense efforts of the 1950s, and has not replaced it with any other system.
| D | Antiballistic Missile Systems |
Active defense systems have been proposed that would use advanced missiles to track and shoot down incoming ICBMs. These are known as antiballistic missile (ABM) systems. The most famous of the antiballistic missile systems was the Strategic Defense Initiative (SDI) proposed by former U.S. president Ronald Reagan in 1983. SDI would have used a combination of laser-equipped satellites and other space-based weapons to destroy ballistic missiles after their launch. Research had begun on SDI, but the program was eventually cancelled due to high cost and the easing of global tensions.
The 1972 Antiballistic Missile (ABM) Treaty signed by the United States and the USSR limits the implementation of antiballistic missile systems. Russia has one system in place around Moscow. The United States had a system in North Dakota, but closed it down due to cost and reliability issues. See also Strategic Arms Limitation Talks.
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