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The Boeing CIM-10 Bomarc (IM-99 Weapon System prior to September 1962) was a supersonic long-range surface-to-air missile (SAM) used during the Cold War for the air defense of North America. In addition to being the first operational long-range SAM, it was the only SAM deployed by the US Air Force.
Contents
- Design and development
- United States
- Bomarc incident
- Modification and deactivation
- Canada
- Variants
- Operators
- Surviving missiles
- References
Stored horizontally in a launcher shelter with movable roof, the missile was erected, fired vertically using rocket boosters to high altitude, and then tipped over into a horizontal Mach 2.5 cruise powered by ramjet engines. This lofted trajectory allowed the missile to operate at a maximum range as great as 250 miles (400 km). Controlled from the ground for most of its flight, when it reached the target area it was commanded to begin a dive, activating an onboard active radar homing seeker for terminal guidance. A radar proximity fuse detonated the warhead, either a large conventional explosive or the W40 nuclear warhead.
The Air Force originally planned for a total of 52 sites covering most of the major cities and industrial regions in the US. The US Army was deploying their own systems at the same time, and the two services fought constantly both in political circles and in the press. Development dragged on, and by the time it was ready for deployment in the late 1950s, the nuclear threat had moved from manned bombers to the intercontinental ballistic missile (ICBM), while the Army had successfully deployed their own system that filled any possible role in the 1960s, in spite of Air Force claims to the contrary.
As testing continued, the Air Force reduced its plans to sixteen sites, and then again to eight with an additional two sites in Canada. The first US site was declared operational in 1959, but with only a single working missile. Bringing the rest of the missiles into service took years, by which time the system was totally obsolete. Deactivations began in 1969 and by 1972 all Bomarc sites had been shut down. A small number were used as target drones, and only a few remain on display today.
Design and development
In 1946, Boeing started to study surface-to-air guided missiles under the United States Army Air Forces project MX-606. By 1950, Boeing had launched more than 100 test rockets in various configurations, all under the designator XSAM-A-1 GAPA (Ground-to-Air Pilotless Aircraft). Because these tests were very promising, Boeing received a USAF contract in 1949 to develop a pilotless interceptor (a term then used by the USAF for air-defense guided missiles) under project MX-1599. The MX-1599 missile was to be a ramjet-powered, nuclear-armed long-range surface-to-air missile to defend the Continental United States from high-flying bombers. The Michigan Aerospace Research Center (MARC) was added to the project soon afterward, and this gave the new missile its name Bomarc (for Boeing and MARC). In 1951, the USAF decided to emphasize its point of view that missiles were nothing else than pilotless aircraft by assigning aircraft designators to its missile projects, and anti-aircraft missiles received F-for-Fighter designations. The Bomarc became the F-99.
Test flights of XF-99 test vehicles began in September 1952 and continued through early 1955. The XF-99 tested only the liquid-fueled booster rocket, which would accelerate the missile to ramjet ignition speed. In February 1955, tests of the XF-99A propulsion test vehicles began. These included live ramjets, but still had no guidance system or warhead. The designation YF-99A had been reserved for the operational test vehicles. In August 1955, the USAF discontinued the use of aircraft-like type designators for missiles, and the XF-99A and YF-99A became XIM-99A and YIM-99A, respectively. Originally the USAF had allocated the designation IM-69, but this was changed (possibly at Boeing's request to keep number 99) to IM-99 in October 1955. In October 1957, the first YIM-99A production-representative prototype flew with full guidance, and succeeded to pass the target within destructive range. In late 1957, Boeing received the production contract for the IM-99A Bomarc A interceptor missile, and in September 1959, the first IM-99A squadron became operational.
The IM-99A had an operational radius of 200 miles (320 km) and was designed to fly at Mach 2.5–2.8 at a cruising altitude of 60,000 feet (18 km). It was 46.6 ft (14.2 m) long and weighed 15,500 pounds (7,000 kg). Its armament was either a 1,000 pounds (450 kg) conventional warhead or a W40 nuclear warhead (7–10 kiloton yield). A liquid-fuel rocket engine boosted the Bomarc to Mach 2, when its Marquardt RJ43-MA-3 ramjet engines, fueled by 80-octane gasoline, would take over for the remainder of the flight. This was the same model of engine used to power both the Lockheed X-7, the Lockheed AQM-60 Kingfisher drone used to test air defenses, and the Lockheed D-21 launched from the back of an SR-71 .
The operational IM-99A missiles were based horizontally in semi-hardened shelters, nicknamed "coffins". After the launch order, the shelter's roof would slide open, and the missile raised to the vertical. After the missile was supplied with fuel for the booster rocket, it would be launched by the Aerojet General LR59-AJ-13 booster. After sufficient speed was reached, the Marquardt RJ43-MA-3 ramjets would ignite and propel the missile to its cruise speed and altitude of Mach 2.8 at 20,000 m (66,000 ft).
When the Bomarc was within 16 km (9.9 mi) of the target, its own Westinghouse AN/DPN-34 radar guided the missile to the interception point. The maximum range of the IM-99A was 400 km (250 mi), and it was fitted with either a conventional high-explosive or a 10 kiloton W-40 nuclear fission warhead.
The Bomarc relied on the Semi-Automatic Ground Environment (SAGE), an automated control system used by NORAD for detecting, tracking and intercepting enemy bomber aircraft. SAGE allowed for remote launching of the Bomarc missiles, which were housed in a constant combat-ready basis in individual launch shelters in remote areas. At the height of the program, there were 14 Bomarc sites located in the US and two in Canada.
The liquid-fuel booster of the Bomarc A was no optimal solution. It took two minutes to fuel before launch, which could be a long time in high-speed intercepts, and its hypergolic propellants (hydrazine and nitric acid) were very dangerous to handle, leading to several serious accidents.
As soon as high-thrust solid-fuel rockets became a reality in the mid-1950s, the USAF began to develop a new solid-fueled Bomarc variant, the IM-99B Bomarc B. It used a Thiokol XM51 booster, and also had improved Marquardt RJ43-MA-7 (and finally the RJ43-MA-11) ramjets. The first IM-99B was launched in May 1959, but problems with the new propulsion system delayed the first fully successful flight until July 1960, when a supersonic KD2U-1/MQM-15A Regulus II drone was intercepted. Because the new booster took up less space in the missile, more ramjet fuel could be carried, increasing the range to 710 km (440 mi). The terminal homing system was also improved, using the world's first pulse Doppler search radar, the Westinghouse AN/DPN-53. All Bomarc Bs were equipped with the W-40 nuclear warhead. In June 1961, the first IM-99B squadron became operational, and Bomarc B quickly replaced most Bomarc A missiles. On 23 March 1961, a Bomarc B successfully intercepted a Regulus II cruise missile flying at 100,000 ft, thus achieving the highest interception in the world up to that date.
Boeing built 570 Bomarc missiles between 1957 and 1964, 269 CIM-10A, 301 CIM-10B.
In September 1958 Air Research & Development Command decided to transfer the Bomarc program from its testing at Cape Canaveral Air Force Station to a new facility on Santa Rosa Island, immediately south of Eglin AFB Hurlburt Field on the Gulf of Mexico. To operate the facility and to provide training and operational evaluation in the missile program, Air Defense Command established the 4751st Air Defense Wing (Missile) (4751st ADW) on 15 January 1958. The first launch from Santa Rosa took place on 15 January 1959.
United States
The first USAF operational Bomarc squadron was the 46th Air Defense Missile Squadron (ADMS), organized on 1 January 1959 and activated on 25 March. The 46th ADMS was assigned to the New York Air Defense Sector at McGuire Air Force Base, New Jersey. The training program, under the 4751st ADW used technicians acting as instructors and was established for a four-month duration. Training included missile maintenance; SAGE operations and launch procedures, including the launch of an unarmed missile at Eglin. In September 1959 the squadron assembled at their permanent station, the Bomarc site near McGuire AFB, and trained for operational readiness. The first Bomarc-A were used at McGuire on 19 September 1959 with Kincheloe AFB getting the first operational IM-99Bs. While several of the squadrons replicated earlier fighter interceptor unit numbers, they were all new organizations with no previous historical counterpart.
ADC's initial plans called for some 52 Bomarc sites around the United States with 120 missiles each but as defense budgets decreased during the 1950s the number of sites dropped substantially. Ongoing development and reliability problems didn't help, nor did Congressional debate over the missile's usefulness and necessity. In June 1959, the Air Force authorized 16 Bomarc sites with 56 missiles each; the initial five would get the IM-99A with the remainder getting the IM-99B. However, in March 1960, HQ USAF cut deployment to eight sites in the United States and two in Canada.
Bomarc incident
Within a year of operations, a Bomarc-A with a nuclear warhead caught fire at McGuire AFB on 7 June 1960 after its on-board helium tank exploded. While the missile's explosives did not detonate, the heat melted the warhead and released plutonium, which the fire crews spread. The Air Force and the Atomic Energy Commission cleaned up the site and covered it with concrete. This was the only major incident involving the weapons system. The site remained in operation for several years following the fire. Since its closure in 1972, the area has remained off limits, primarily due to low levels of plutonium contamination. In 2002, the concrete at the site was removed and transported to Lakehurst Naval Air Station for transport by rail to a site for proper disposal.
Modification and deactivation
In 1962, the US Air Force started using modified A-models as drones; following the October 1962 tri-service redesignation of aircraft and weapons systems they became CQM-10As. Otherwise the air defense missile squadrons maintained alert while making regular trips to Santa Rosa Island for training and firing practice. After the inactivation of the 4751st ADW(M) on 1 July 1962 and transfer of Hurlburt to Tactical Air Command for air commando operations the 4751st Air Defense Squadron (Missile) remained at Hurlburt and Santa Rosa Island for training purposes.
In 1964, the liquid-fueled Bomarc-A sites and squadrons began to be deactivated. The sites at Dow and Suffolk County closed first. The remainder continued to be operational for several more years while the government started dismantling the air defense missile network. Niagara Falls was the first BOMARC B installation to close, in December 1969; the others remained on alert through 1972. In April 1972, the last Bomarc B in U.S. Air Force service was retired at McGuire and the 46th ADMS inactivated and the base was deactivated.
In the era of the intercontinental ballistic missiles the Bomarc, designed to intercept relatively slow manned bombers, had become a useless asset. The remaining Bomarc missiles were used by all armed services as high-speed target drones for tests of other air-defense missiles. The Bomarc A and Bomarc B targets were designated as CQM-10A and CQM-10B, respectively.
Following the accident, the McGuire complex has never been sold or converted to other uses and remains in Air Force ownership, making it the most intact site of the eight in the US. It has been nominated to the National Register of Historic Sites. Although a number of IM-99/CIM-10 Bomarcs have been placed on public display, because of concerns about the possible environmental hazards of the thoriated magnesium structure of the airframe several have been removed from public view.
Russ Sneddon, director of the Air Force Armament Museum, Eglin Air Force Base, Florida provided information about missing CIM-10 exhibit airframe serial 59-2016, one of the museum's original artifacts from its founding in 1975 and donated by the 4751st Air Defense Squadron at Hurlburt Field, Eglin Auxiliary Field 9, Eglin AFB. As of December 2006, the suspect missile was stored in a secure compound behind the Armaments Museum. In December 2010, the airframe was still on premises, but partly dismantled.
Canada
The Bomarc Missile Program was highly controversial in Canada. The Progressive Conservative government of Prime Minister John Diefenbaker initially agreed to deploy the missiles, and shortly thereafter controversially scrapped the Avro Arrow, a supersonic manned interceptor aircraft, arguing that the missile program made the Arrow unnecessary.
Initially, it was unclear whether the missiles would be equipped with nuclear warheads. By 1960 it became known that the missiles were to have a nuclear payload, and a debate ensued about whether Canada should accept nuclear weapons. Ultimately, the Diefenbaker government decided that the Bomarcs should not be equipped with nuclear warheads. The dispute split the Diefenbaker Cabinet, and led to the collapse of the government in 1963. The Official Opposition and Liberal Party leader Lester "Mike" Pearson originally was against nuclear missiles, but reversed his personal position and argued in favor of accepting nuclear warheads. He won the 1963 election, largely on the basis of this issue, and his new Liberal government proceeded to accept nuclear-armed Bomarcs, with the first being deployed on 31 December 1963. When the nuclear warheads were deployed, Pearson's wife, Maryon, resigned her honorary membership in the anti-nuclear weapons group, Voice of Women.
Canadian operational deployment of the Bomarc involved the formation of two specialized Surface/Air Missile squadrons. The first to begin operations was No. 446 SAM Squadron at RCAF Station North Bay, Ontario which was the command and control center for both squadrons. With construction of the compound and related facilities completed in 1961, the squadron received its Bomarcs in 1961, without nuclear warheads. The squadron became fully operational from 31 December 1963, when the nuclear warheads arrived, until disbanding on 31 March 1972. All the warheads were stored separately and under control of Detachment 1 of the USAF 425th Munitions Maintenance Squadron. During operational service, the Bomarcs were maintained on stand-by, on a 24-hour basis, but were never fired, although the squadron test-fired the missiles at Eglin AFB, Florida on annual winter retreats.
No. 447 SAM Squadron operating out of RCAF Station La Macaza, Quebec was activated on 15 September 1962 although warheads were not delivered until late 1963. The squadron followed the same operational procedures as No. 446, its sister squadron. With the passage of time the operational capability of the 1950s-era Bomarc system no longer met modern requirements; the Department of National Defence deemed that the Bomarc missile defense was no longer a viable system, and ordered both squadrons to be stood down in 1972. The bunkers and ancillary facilities remain at both former sites.
Variants
Operators
Locations under construction but not activated. Each site was programmed for 28 IM-99B missiles:
Reference for BOMARC units and locations:
Surviving missiles
Below is a list of museums or sites which have a Bomarc missile on display: