The first Thor
intermediate-range ballistic missile (IRBM)
launch from Vandenberg AFB, December 16, 1958
United States and Soviet Union first started developing intercontinental
ballistic missiles (ICBMs) in the 1950s, because there was no way for a
target to defend against them. Missile warheads are so small and travel so
fast that it is virtually impossible for a defensive weapon to hit them-a
fact that remains almost as true today as it was during the 1950s. But for
decades, the United States and Russia have spent tremendous amounts of
money trying to develop a defence against ballistic missiles.
The Strategic Air Command's first
intercontinental ballistic missile (ICBM) was the Convair B-65 Atlas
(later redesignated SM-65). The Atlas became operational in 1959. Because
of the vulnerability
of the Atlas while above ground, an underground silo was developed.
An elevator raised it to ground level for launching. While on alert duty,
the Atlas missile
was maintained in the fully raised (above ground) position since it could
not be launched from its underground silo.
first serious study of what was called an “anti-missile missile” dates to
as early as 1956, when a U.S. scientific group evaluated the challenges of
shooting down ballistic missile warheads. They realized that warheads were
small and might not show up on radar, and responding to an attack in time
would be difficult. But the biggest problem was getting a missile into the
vicinity of the attacking warhead and destroying it. Because they could
not get close to their targets, early anti-missile proposals all relied on
nuclear warheads, which had a wide enough explosive radius that they could
compensate for the inaccuracy of the missile. In the mid-1950s, the U.S.
Army built an “anti-ballistic missile” (ABM) known as the Nike-Zeus with
some anti-missile capabilities, but by 1959, President Dwight D.
Eisenhower's Presidential Science Advisory Committee (PSAC) ruled that
Nike-Zeus was too slow, too vulnerable to attack, and could not
differentiate between real warheads and decoys.
early 1960s, U.S. Air Force scientists had evaluated the possibility of
using lasers to burn missile warheads in flight but determined that the
lasers could not produce enough energy to damage a warhead, which was
small and fast and already designed to withstand tremendous heat during
re-entry into the Earth's atmosphere. The U.S. Army began developing new
radars encased in hardened structures and a faster missile named the
Sprint; the new radars and missile were combined into a system named
Nike-X. In 1966, the highest level military leaders recommended that this
system be deployed to defend the entire United States against Soviet ICBM
attack, a so-called “area defence.” But Secretary of Defence Robert
McNamara resisted. Instead, McNamara pushed the development of
independently targetable re-entry vehicles, or MIRVs, which allowed a
single ICBM to attack multiple targets. This assured that no attack on the
United States could destroy a large enough number of American ICBMs so as
to prevent it from staging a devastating counterattack, and supposedly
made a Soviet ICBM attack unthinkable by the Soviet military.
Titan I ICBM launch at Vandenberg
Air Force Base, December, 1960
1967, McNamara agreed to start work on a modified, scaled back version of
the Nike-X system dubbed Sentinel. McNamara argued that this reduced
system would focus on the Chinese missile threat rather than the Soviet
threat and as such, would be less provocative. Sentinel would have
resulted in basing large numbers of powerful nuclear warheads atop Spartan
missiles around major American cities.
1969, the new administration under President Richard Nixon re-evaluated the
Sentinel system and scaled it back dramatically, renaming it Safeguard.
Instead of an area defense system, Safeguard would be a “point defence”
system intended to protect ICBM sites. By 1970, both the United States and
Soviet Union had approximately the same number of ICBMs, and the two
countries started discussing arms control, signing the Strategic Arms
Limitation Treaty (SALT) in 1971. In May 1972, they both signed the
Anti-Ballistic Missile (ABM) Treaty. This treaty limited both countries to
two ABM sites each, one to protect the Nation's capital and the other to
protect an ICBM site. It also restricted testing of systems capable of
shooting down ICBMs as well as deployment of new ABM radars deep inside a
Throughout the 1950s and 1960s, while the United States was developing its
ABM systems, the Soviet Union was also conducting a massive ABM
development program. The Soviet military tested huge radars and powerful
missile interceptors at a big facility known as Sary Shagan. But despite
all of their efforts, the Soviets were unable to develop an effective
missile defence system. They started a system for defending Moscow in the
1960s and eventually completed it after a number of setbacks.
Boeing LGM-30A Minuteman I. The
Minuteman I, formally known as the SM-80,
was a second generation intercontinental ballistic missile (ICBM) using
solid propellants rather than liquid fuels.
1975, the United States deployed its ABM system at Grand Forks, North
Dakota, to defend ICBM silos. But Congress closed the facility within a
year because there was no way that its 100 missile interceptors could
defend against thousands of incoming Soviet warheads. The Soviet Union
maintained its limited ABM system around Moscow and updated it starting in
the 1980s. But the system never worked properly. Critics within the Soviet
military noted that the defensive system itself would detonate dozens of
nuclear weapons directly over the city. Proponents of the system
rationalized that the system was intended to defend against a much more
limited missile attack from China, but outdated technology made even this
reduced task seem nearly impossible.
23, 1983, President Ronald Reagan gave a speech announcing a major shift
in American defence policy. Reagan declared that the United States would
seek to develop a missile shield to defend the entire country against
Soviet ICBM attack. This shield would rely upon many highly advanced and
unproven technologies, such as lasers and particle beams, and much of it
would presumably be deployed in space. The lasers would attack Soviet
ICBMs while they were still relatively slow and lifting off the ground,
when they were most vulnerable (a period known as the “boost phase”). The
Soviets had also started developing a large radar deep inside their
territory near Krasnoyarsk that directly violated the ABM Treaty. When the
Americans discovered this in July 1983, relations deteriorated.
immediately labelled Reagan's defence plan “Star Wars” and ridiculed it for
being totally unrealistic. Reagan soon established the Strategic Defence
Initiative, or SDI, to develop the advanced technologies necessary for
effective missile defence. The SDI budget grew to nearly three billion
dollars a year, but even so, many of its most advanced technologies proved
beyond reach. In the late 1980s, SDI plans were scaled back. Instead of
lasers, one proposed solution was to use thousands of small orbiting
interceptors nicknamed “Brilliant Pebbles.” These would be combined with
many small orbiting sensors nicknamed “Brilliant Eyes.” Both proposals
ultimately led to a new approach to spacecraft design: an effort to
develop smaller, cheaper spacecraft. Despite the expenditure, SDI did not
make the kind of progress necessary to achieve Reagan's grand vision, but
it did greatly concern Soviet military and government leaders, who often
had more faith in American technology than the Americans did themselves.
President George H.W. Bush scaled back the SDI program after the end of
the Cold War but still sought to develop some form of missile defence. The
Iraqi use of Scud missiles during the 1991 Persian Gulf War demonstrated
that American troops abroad were also at risk from missile attack. This
threat prompted greater focus on so-called “theater” ballistic missile
defences to shoot down shorter-range missiles like the Scud, which are
slower and easier to hit than ICBMs.
Bill Clinton defeated Bush in the 1992 presidential election, he scaled
back the effort even further and focused it on developing several ground
and sea-based interceptors for defending against a small attack from
nations such as North Korea, Iraq, and Iran. These interceptors would
directly hit their targets at high speed and did not need a warhead. The
U.S. Air Force also began work on an Airborne Laser (ABL) that would be
mounted on a converted Boeing 747 airplane and used to shoot down missiles
like the Scud. The Strategic Defence Initiative Organization was renamed
the Ballistic Missile Defence Organization (BMDO).
next eight years, Clinton continued missile defence research at a slower
pace. But in 1998, North Korea surprised the world by launching a
three-stage ballistic missile over Japan. This prompted renewed debate
within the United States about the threat from ballistic missiles, and
presidential candidate George W. Bush made missile defence a key part of
his campaign. When Bush was sworn in as president in January 2001, he
quickly moved to increase missile defence development, pushing deployment
of a small system based in Alaska that could intercept a small number of
ICBMs launched at the continental United States. In December 2001, Bush
announced his intention to withdraw the United States from the ABM Treaty.
Such a move was necessary if the United States was going to test more
advanced systems that would otherwise violate the treaty.