CIM-10 Bomarc

The Boeing CIM-10 Bomarc (IM-99 Weapon System prior to September 1962) was a supersonic interceptor for Cold War air defense of North America which, in addition to being the first long-range anti-aircraft missile (cf. proposed WIZARD predecessor), was the only SAM deployed by the United States Air Force. Stored horizontally in a launcher shelter with movable roof, the aircraft was erected to fire vertically using rocket boosters and then was ramjet-powered during midcourse command guidance to a dive point. During the "Homing Dive", the missile's onboard AN/DPN-34 radar allowed the BOMARC to guide itself to the target (e.g., enemy bomber or formation) and a radar proximity fuze detonated the warhead (conventional or 10 kiloton nuclear W-40). After the May 17, 1957, $7 million initial contract for operational aircraft; the "Interceptor Missile" was deployed at launch areas in Canada and the United States (e.g., the 1960 Fort Dix IM-99 accident contaminated a launch area.) Boeing indicated: "Differences in the Langley Base layout are due to planning for accommodation of the advanced missile system [(IM-99B) ground equipment with equipment for] the IM-99A system". Actual launches were from Florida test range sites (AFMTC & Eglin's Santa Rosa Island) and controlled by AN/GPA-35 and/or AN/FSQ-7 computers, e.g., the Montgomery SAGE Center commanded 3 BOMARCs simultaneously in-flight during a May 1960 test. BOMARC launches as target drones began at Vandenberg Air Force Base on 25 August 1966 (the 1st Vandenberg BOMARC launch was 14 October 1964).



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 mi and was designed to fly at Mach 2.5–2.8 at a cruising altitude of 60000 ft. It was 46.6 ft long and weighed 15500 lb. Its armament was either a 1000 lb conventional warhead or a W40 nuclear warhead (7–10 kiloton yield). A liquid fuelled 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.

The operational IM-99A missiles were based horizontally in semi-hardened shelters ("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 20000 m.

When the Bomarc was within 16 km 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, and it was fitted with either a conventional high-explosive or a 10 kt 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 United States 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 can be a long time in high-speed intercepts, and its hypergolic fuels (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. 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.

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.

Operational history
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 AFB, 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 went operational 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 US and two in Canada.

Within a year of becoming operational, a Bomarc-A with a nuclear warhead caught fire at McGuire AFB on 7 June 1960 following the explosive rupture of its onboard helium tank. While the missile's explosives didn't detonate, the heat melted the warhead, releasing plutonium which the fire crews then spread around. The Air Force and the Atomic Energy Commission cleaned up the site and covered it with concrete; fortunately, this was the only major incident involving the weapons system. The site remained in operation for several years following the fire, but after its closure in 1972, the accident resulted in that area remaining off limits to the present day, 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 railheading to a site for proper disposal.

In 1962, the U.S. 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 inactivated. The sites at Dow and Suffolk County closed first. The remainder soldiered on 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 USAF service was retired at McGuire and the 46th ADMS inactivated.



The Bomarc, designed to intercept relatively slow manned bombers, had become a useless asset in the era of the intercontinental ballistic missile. 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.

Notably, due to 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 United States. 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, concerns about the possible environmental hazards of the thoriated magnesium structure of the airframe have resulted in several being removed from public view.

Russ Sneddon, director of the Air Force Armament Museum, Eglin AFB, 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 partially dismantled.

Canada and the Bomarc
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 operations
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 centre 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 defence 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

 * XF-99 (experimental for booster research)
 * XF-99A/XIM-99A (experimental for ramjet research)
 * YF-99/YIM-99 (service-test)
 * IM-99A (initial production)
 * IM-99B ("advanced")
 * CQM-10 (target drone)

Operators

 * 🇨🇦 Canada
 * Royal Canadian Air Force from 1955–1968 / Canadian Forces from 1968–1972
 * 446 SAM Squadron: 28 IM-99B, CFB North Bay, Ontario 1962–1972
 * Bomarc site located at 46.42944°N, -79.47111°W
 * 447 SAM Squadron: 28 IM-99B, La Macaza, Quebec (La Macaza – Mont Tremblant International Airport) 1962–1972
 * Bomarc site located at 46.41139°N, -74.76889°W (Approximately)


 * 🇺🇸 United States
 * United States Air Force Air (later Aerospace) Defense Command


 * 6th Air Defense Missile Squadron, 56 IM-99A
 * Activated on 1 February 1959
 * Assigned to: New York Air Defense Sector
 * Inactivated 15 December 1964
 * Stationed at: Suffolk County AFB, New York
 * Bomarc site located 3 miles SW at 40.83333°N, -72.68083°W


 * 22d Air Defense Missile Squadron: 28 IM-99A/28 IM-99B
 * Activated on 15 September 1959
 * Assigned to: Washington Air Defense Sector
 * Reassigned to: 33d Air Division, 1 April 1966
 * Reassigned to: 20th Air Division, 19 November 1969
 * Inactivated: 31 October 1972
 * Stationed at: Langley AFB, Virginia
 * Bomarc site located 3 miles WNW at 37.09917°N, -76.47972°W


 * 26th Air Defense Missile Squadron: 28 IM-99A/28 IM-99B
 * Activated 1 March 1959
 * Assigned to: Boston Air Defense Sector
 * Reassigned to: 35th Air Division, 1 April 1966
 * Reassigned to: 21st Air Division, 19 November 1969
 * Inactivated: 30 April 1972
 * Stationed at: Otis AFB, Massachusetts
 * Bomarc site located 1 mile NNW at 41.68222°N, -70.53917°W


 * 30th Air Defense Missile Squadron: 28 IM-99A
 * Activated on 1 June 1959
 * Assigned to Bangor Air Defense Sector
 * Inactivated: 15 December 1964
 * Stationed at Dow AFB, Maine
 * Bomarc site located 4 mils NNE at 44.85306°N, -68.78639°W


 * 35th Air Defense Missile Squadron: 56 IM-99B
 * Activated 1 June 1960
 * Assigned to Syracuse Air Defense Sector
 * Reassigned to: Detroit Air Defense Sector, 4 September 1963
 * Reassigned to: 34th Air Division, 1 April 1966
 * Reassigned to: 35th Air Division, 15 September 1969
 * Inactivated: 31 December 1969
 * Stationed at: Niagara Falls Air Force Missile Site, New York
 * Bomarc site located at 43.1175°N, -78.94694°W


 * 37th Air Defense Missile Squadron: 28 IM-99B
 * Activated 1 March 1960
 * Assigned to 30th Air Division
 * Reassigned to: Sault Sainte Marie Air Defense Sector, 1 April 1960
 * Reassigned to: Duluth Air Defense Sector, 1 October 1963
 * Reassigned to: 29th Air Division, 1 April 1966
 * Reassigned to: 23d Air Division, 19 November 1969
 * Inactivated 31 July 1972
 * Stationed at: Kincheloe AFB, Michigan
 * Bomarc site located 9 miles NW at 46.34806°N, -84.805°W


 * 46th Air Defense Missile Squadron: 28 IM-99A/56 IM-99B
 * Activated 1 January 1959
 * Assigned to New York Air Defense Sector
 * Reassigned to: 21st Air Division, 1 April 1966
 * Reassigned to: 35th Air Division, 1 December 1957
 * Reassigned to: 21st Air Division, 19 November 1969
 * Inactivated 31 October 1972
 * Stationed at: McGuire AFB, New Jersey
 * Bomarc site located 4 miles ESE at 40.035°N, -74.44139°W


 * 74th Air Defense Missile Squadron: 28 IM-99B
 * Activated 1 April 1960
 * Assigned to Duluth Air Defense Sector
 * Reassigned to: 29th Air Division, 1 April 1966
 * Reassigned to: 23d Air Division, 19 November 1969
 * Inactivated 30 April 1972
 * Stationed at: Duluth International Airport, Minnesota
 * Bomarc site located 10 miles NE at 46.93222°N, -91.88333°W


 * 4751st Air Defense Missile Squadron
 * Activated 15 January 1959
 * Assigned to 73d Air Division (Weapons)
 * Reassigned to: 32d Air Division, 1 October 1959
 * Reassigned to: Montgomery Air Defense Sector, 1 July 1962
 * Reassigned to: Air Defense, Tactical Air Command, 1 September 1979
 * Inactivated 30 September 1979
 * Stationed at: Eglin Auxiliary Field #9 (Hurlburt Field), Florida
 * Bomarc site located on Santa Rosa Island at 30.38833°N, -86.80778°W
 * Bomarc site located at Eglin Auxiliary Field #5 (Piccolo Field) at 30.59361°N, -86.62167°W

Locations under construction but not activated. Each site was programmed for 28 IM-99B missiles:
 * Camp Adair, Oregon 44.70222°N, -123.2°W
 * Charleston AFB, South Carolina
 * Ethan Allen AFB, Vermont 44.51056°N, -73.16361°W
 * Paine Field, Washington 47.91194°N, -122.26528°W
 * Travis AFB, California 38.48722°N, -121.88528°W
 * Truax Field, Wisconsin 43.19083°N, -89.15417°W
 * Vandenberg AFB, California 34.72972°N, -120.50417°W

Reference for BOMARC units and locations:

Surviving missiles
Below is a list of museums or sites which have a Bomarc missile on display:
 * Air Force Armament Museum, Eglin Air Force Base, Florida
 * Air Force Space & Missile Museum, Cape Canaveral Air Force Station, Florida
 * Alberta Aviation Museum, Edmonton, Alberta, Canada
 * Canada Aviation Museum, Ottawa, Ontario, Canada
 * Hill Aerospace Museum, Hill Air Force Base, Utah
 * Historical Electronics Museum, Baltimore, Maryland (display of AN/DPN-53, the first airborne pulse-doppler radar, used in the Bomarc)
 * Illinois Soldiers & Sailors Home, Quincy, Illinois
 * Keesler Air Force Base, Biloxi, Mississippi
 * Museum of Aviation, Robins Air Force Base, Warner Robins, Georgia
 * National Atomic Museum, Kirtland Air Force Base, Albuquerque, New Mexico
 * National Museum of the United States Air Force, Wright-Patterson Air Force Base, Ohio
 * Octave Chanute Aerospace Museum (former Chanute AFB), Rantoul, Illinois
 * Peterson Air and Space Museum, Peterson Air Force Base, Colorado
 * Strategic Air and Space Museum, Ashland, Nebraska
 * US Air Force History and Traditions Museum, Lackland Air Force Base, San Antonio, Texas
 * Vandenberg Air Force Base (Space and Missile Heritage Center), California. Bomarc not for public access.