The Douglas
GAM-87A Skybolt was an
air-launched ballistic missileAn air-launched ballistic missile or ALBM is a ballistic missile launched from an aircraft. This class of missile never saw active use. The only known missile of this type, the AGM-48 Skybolt, intended to be launched from a B-52 Stratofortress bomber, was in development by the United States Air...
(ALBM) developed during the late 1950s. It was intended to provide a mobile basing for the USAF's ICBM missile force by mounting them on heavy
bomberA bomber is a military aircraft designed to attack ground and sea targets, primarily by dropping bombs on them.-Classifications of bombers:...
s rather than in fixed
missile siloA missile silo is an underground, vertical cylindrical container for the storage and launching of intercontinental ballistic missiles . They typically have the missile some distance under the surface, protected by a large "blast door" on top....
s. The UK joined the program in 1960, intending to use it on their
V bomberThe term V bomber was used for the Royal Air Force aircraft during the 1950s and 1960s that comprised the United Kingdom's strategic nuclear strike force...
force. A series of test failures and the development of submarine launched ballistic missiles (SLBMs) eventually led to its cancellation in the mid-1960s. The UK had decided to base its entire 1960s deterrent force on Skybolt, and its cancellation led to a major confrontation between the UK and US, known today as the "Skybolt Crisis". This was solved during a
series of meetingsThe Nassau Agreement, signed in December 1962, was a treaty negotiated between President John F. Kennedy for the United States and Prime Minister Harold Macmillan for the United Kingdom...
that led to the
Royal NavyThe Royal Navy of the United Kingdom is the oldest of HM Armed Forces . From the beginning of the 18th century until well into the 20th century, it was the most powerful navy in the world, playing a key part in establishing the British Empire as the dominant world power from 1815 until the early...
gaining the
UGM-27 PolarisThe Polaris missile was a two-stage solid-fuel nuclear-armed submarine-launched ballistic missile built during the Cold War by Lockheed Corporation of California for the United States Navy. It was designed to be used as part of the Navy's contribution to the United States arsenal of nuclear...
missile and construction of the
Resolution class submarineThe Resolution-class submarine armed with the Polaris missile was the United Kingdom's primary nuclear deterrent from the late 1960s to 1994, when they were replaced by the Vanguard-class submarine carrying the Trident II.-Background:...
s to launch them.
Background
Nuclear weapons theorists had speculated about how to integrate the flexibility and positive control (over the attack) of the manned bomber with the invulnerability (in the attack) of the ballistic missile. The introduction of useful
surface-to-air missileA Surface to Air Missile or ground-to-air missile is a missile designed to be launched from the ground to destroy aircraft. It is a type of anti-aircraft system....
s in the 1950s rendered flight over enemy territory much more dangerous. Yet the Air Force and military planners were, in the mid-1950s, reluctant to simply hand over the nuclear strike capability to missiles, which after launch were no longer under positive control, could not be recalled or redirected, and would reach their targets within a matter of minutes after the order to fire. The missiles of the day were all filled with nonstorable fuel and were launched from above ground, making them vulnerable to attack - the first ICBMs, Atlas 1 and Titan 1 were of this type.
In addition, the accuracy of missiles in the 1950s made them useless as precision strike weapons. They could attack area targets like cities, but could not reliably and accurately attack precision strike targets like enemy bomber bases, hardened command and control centers, naval bases, or weapons storage areas. Initially, western ballistic missiles could not even reach such targets, which would be located deep within interior of the Sino-Soviet land mass in Asia. Therefore the potential integration of aircraft with the invulnerability of the ballistic missile was intriguing prospect to 1950s military planners.
Basing the strike package on aircraft offered a flexibility that missiles could not match. For instance, the bombers could stand off from the targets and wait for instructions from secure command centers to attack targets that were missed in an initial strike. Additionally, the bombers could use long-range weapons to strike known air defenses, and then overfly them to deliver precision strikes with conventional bombs.
Secondly, and most importantly, this mode of deployment meant that the strike force was rendered almost invulnerable. The bombers could fly to staging areas well outside the range of even the longest-legged defenses, and strike with impunity. This allowed for gradual escalation and a possible backing down through diplomacy. A ground-based missile cannot be used in the same fashion; it is either launched or not. If threatened with a nuclear strike, this presents their owners with the 'use them or lose them' predicament.
For the British, their dilemma was a matter of geography and financial resources. No fixed land based ballistic missile system could be credibly installed in the British Isles; they were well within the range of Soviet air strikes. The limited land mass available meant it would be relatively easy for missile sites to be spotted no matter what security measures were taken. Suitable locations for construction also carried a social and politcal cost. Fixed land based ballistic missile sites need many thousands of acres per squadron (typically ten missiles); and the squadrons need to be apportioned over many thousands of square miles, so that no single attack could conceivably destroy them all in one strike.
Development
In 1958 several US contractors demonstrated that large ballistic missiles could be launched from strategic bombers at high altitude. The use of
astronavigationCelestial navigation, also known as astronavigation, is a position fixing technique that was devised to help sailors cross the featureless oceans without having to rely on dead reckoning to enable them to strike land. Celestial navigation uses angular measurements between common celestial objects...
systems for mid-flight corrections of an inertial guidance platform, similar to that of the US Navy's SLBM systems, led to an accuracy similar to that of their existing ground-based missiles.
The USAF was interested and began accepting bids for development systems in early 1959. Douglas Aircraft received the prime contract in May, and in turn subcontracted to Northrop for the guidance system,
AerojetAerojet is a major rocket and missile propulsion manufacturer based primarily in Sacramento, California with divisions in Redmond, WA; Orange, VA; Gainesville, VA; and Camden, AR. They are the only US propulsion company that provides both solid rocket motors and liquid rocket engines...
for the propulsion system, and
General ElectricThe General Electric Company, or GE , is a multinational American technology and services conglomerate incorporated in the State of New York. In 2009, Forbes ranked GE as the world's largest company...
for the reentry vehicle. The system was initially known as WS-138A and was given the official name GAM-87 Skybolt in 1960.
At the same time the
Royal Air ForceThe Royal Air Force is the United Kingdom's air force, the oldest independent air force in the world. Formed on 1 April 1918, the RAF has taken a significant role in British military history ever since, playing a large part in World War II and in more recent conflicts.The RAF operates almost 1,109...
was having problems with their IRBM missile project, the
Blue StreakThe Blue Streak missile was a British ballistic missile designed in 1955. The ballistic missile programme was cancelled in 1960 but the rocket was used as the first-stage of the European satellite launcher Europa...
, which was long overdue. At the same time, they faced the same problems with the dwindling survivability of their existing nuclear deterrent, the V-bomber fleet. The long-range Skybolt would eliminate the need for both the Blue Streak and the
Blue Steel IIBlue Steel was a British air-launched, rocket-propelled nuclear stand-off missile, built to arm the V bomber force. It was the primary British nuclear deterrent weapon until the Royal Navy started operating Polaris missile armed nuclear submarines....
standoff missile, then under development.
Prime MinisterThe Prime Minister of the United Kingdom of Great Britain and Northern Ireland is the political leader of the United Kingdom and the Head of Her Majesty's Government...
MacmillanMaurice Harold Macmillan, 1st Earl of Stockton, OM, PC was a British Conservative politician and Prime Minister of the United Kingdom from 10 January 1957 to 18 October 1963....
met
PresidentThe President of the United States is the head of state and head of government of the United States and is the highest political official in the United States by influence and recognition...
Eisenhower in May 1960 and agreed to purchase 144 Skybolts for the RAF, and Blue Streak and Blue Steel II were both cancelled. By agreement, British funding for research and development was limited to that required to modify the V-bombers to take the missile.
Tests
By 1961, several test articles were ready for testing from USAF
B-52The Boeing B-52 Stratofortress is a long-range, subsonic, jet-powered, strategic bomber operated by the United States Air Force since 1955....
bombers, with drop-tests starting in January. In England compatibility trials with mockups started on the Vulcan. Powered tests started in April 1962, but the test series went badly, with the first five trials ending in failure of one sort or another. The first fully successful flight occurred on December 19, 1962.
Cancellation
By this point the value of the Skybolt system had been seriously eroded. The US Navy's Polaris SLBM had recently gone into service, with overall capabilities similar to Skybolt, but with "loiter times" on the order of months instead of hours. Additionally, the US Air Force itself was well into the process of developing the Minuteman missile, whose improved accuracy reduced the need for any bomber attacks.
Robert McNamaraRobert Strange McNamara was an American business executive and the eighth Secretary of Defense, serving under Presidents John F. Kennedy and Lyndon B. Johnson from 1961 to 1968. Following that he served as President of the World Bank from 1968 until 1981...
was particularly opposed to the bomber force and repeatedly stated he felt that the combination of SLBMs and ICBMs would render them useless. He pressed for cancellation of the Skybolt program as unnecessary.
The British, on the other hand, had cancelled all other projects to concentrate fully on Skybolt. When McNamara informed them that they were considering cancelling the program in November 1962, a firestorm of protest broke out in the House of Commons.
Jo GrimondJoseph "Jo" Grimond, Baron Grimond CH, CBE, PC was a British politician, leader of the Liberal Party from 1956 to 1967 and again briefly in 1976.-Early life:...
noted "Does not this mark the absolute failure of the policy of the independent deterrent? Is it not the case that everybody else in the world knew this, except the Conservative Party in this country?" As the political row grew into a major crisis, an emergency meeting between parties from the US and UK was called, leading to the
Nassau agreementThe Nassau Agreement, signed in December 1962, was a treaty negotiated between President John F. Kennedy for the United States and Prime Minister Harold Macmillan for the United Kingdom...
.
Over the next few days a
new plan was hammered outThe Polaris Sales Agreement was an agreement between the United States and the United Kingdom which formally arranged for the Polaris missile system to be provided to the UK to maintain its independent nuclear deterrent. The arrangement had been set up in principle as a result of the Nassau Agreement...
that saw the UK purchase the Polaris SLBM, but equipped with British warheads that lacked the
dual-keyThe two-man rule is a control mechanism designed to achieve a high level of security for especially critical material or operations. Under this rule all access and actions requires the presence of two authorized people at all times.-Nuclear weapons:...
system. The UK would thus retain its independent deterrent force, although its control passed from the RAF largely to the
Royal NavyThe Royal Navy of the United Kingdom is the oldest of HM Armed Forces . From the beginning of the 18th century until well into the 20th century, it was the most powerful navy in the world, playing a key part in establishing the British Empire as the dominant world power from 1815 until the early...
. The Polaris, a much better weapon system for the UK, was a major "scoop" and has been referred to as “almost the bargain of the century” The RAF kept a tactical nuclear capability with the
WE.177WE.177 was the last air-delivered tactical nuclear weapon of the British Armed Forces. There were three versions; WE.177A was a boosted fission weapon, while WE.177B and WE.177C were thermonuclear weapons...
which armed V-bombers and later the
Panavia TornadoThe Panavia Tornado is a family of twin-engine combat aircraft, which was jointly developed by the United Kingdom, West Germany and Italy. There are three primary versions of the Tornado; the Tornado IDS fighter-bomber, the suppression of enemy air defences Tornado ECR and the Tornado ADV ...
force. The "Skybolt Crisis" was a major event in the eventual downfall of the Macmillan administration.
Limited flight tests with the remaining
XGAM-87A missiles continued after program cancellation. In June 1963, the
XGAM-87A was redesignated as XAGM-48A.
Description
The GAM-87 was powered by a two-stage solid-fuel rocket motor. Each B-52H was to carry four missiles, two under each wing on side-by-side pylons, while the
Avro VulcanThe Avro Vulcan is a delta wing subsonic jet bomber that was operated by the Royal Air Force from 1953 until 1984. The Vulcan was part of the RAF's V bomber force, which fulfilled the role of nuclear deterrence against the Soviet Union during the Cold War. It was also used in a conventional bombing...
carried one each on smaller pylons. The missile was fitted with a tailcone to reduce drag while on the pylon, which was ejected shortly after being dropped from the plane. After first stage burnout, the Skybolt coasted for a while before the second stage ignited. First stage control was by eight movable tail fins, while the second stage was equipped with a gimballed nozzle.
Guidance was entirely by inertial platform. The current position was constantly updated from the host aircraft though accurate fixes, meaning that the accuracy of the platform inside the missile was not as critical.
See also
Further reading
- Neustadt, Richard E. Report to JFK: The Skybolt Crisis in Perspective. Ithaca, NY: Cornell University Press, 1999. ISBN 0-8014-3622-2.
External links