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| AGM-69 SRAM | |
|---|---|
 SRAM missile carrying a W69 warhead | |
| Type | Nuclearair-to-surface missile |
| Place of origin | United States |
| Service history | |
| In service | 1972–1993 |
| Used by | United States |
| Wars | Cold War |
| Production history | |
| Designer | Boeing |
| Designed | 1965 |
| Manufacturer | Boeing |
| Unit cost | $592,000 |
| Produced | 1971–1975 |
| No. built | 1,500 |
| Specifications | |
| Mass | 2,230 lb (1,010 kg) |
| Length | 15 ft 10 in (4.83 m) w/ tail fairing, 14 ft 0 in (4.27 m) without |
| Diameter | 17.5 in (0.44 m) |
| Warhead | W69 nuclear warhead |
| Blast yield | 170 to 200 kilotonnes of TNT (710 to 840 TJ) |
| Engine | Lockheed SR75-LP-1 two-pulsesolid-fueled rocket |
Operational range | 110 nautical miles (200 km) |
| Maximum speed | Mach 3 |
Guidance system | General Precision/Kearfott KT-76Inertial measurement unit |
| Accuracy | 1,400 ft (430 m) |
| Transport | Airplane |
TheBoeingAGM-69 SRAM (Short-Range Attack Missile) was anuclearair-to-surface missile. It had a range of up to 110 nautical miles (200 km; 130 mi), and was intended to allowUS Air Forcestrategic bombers to penetrate Soviet airspace by neutralizingsurface-to-air missile defenses.
The SRAM was designed to replace the olderAGM-28 Hound Dogstandoff missile which was tasked with the same basic role. The Hound Dog was a very large missile that could only be carried in pairs by theB-52, so some aircraft were tasked with suppressing Soviet missile and radar sites while others would carry on to strike their strategic targets. The SRAM was so much smaller that a number could be carried along with other weapons, allowing a single aircraft to blast a nuclear path through to its targets.
The SRAM entered service in 1972 and was carried by a number of aircraft, including theB-52,FB-111A, and theB-1B. In September 1980 a ground fire raised concerns about the safety of the warhead, and in 1990 they were temporarily removed from service while safety checks were carried out. These revealed a number of the missiles' rocket motors had developed cracks that could have resulted in them exploding when launched.
The SRAM was removed from service in 1993. The weapon was to be replaced by theAGM-131 SRAM II and the newW89 warhead, but the program was terminated at the end of the Cold War.
The Air Force had been considering the idea of a medium-range missile to attack air defense sites since the mid-1950s. This concept became more important with the Soviet introduction of theSA-2 missile, which presented a serious threat to theUnited States Air ForceStrategic Air Command's (SAC) bomber fleet. The first attempt to address this role led to theGAM-67 Crossbow, which flew for the first time in 1956. However, the Crossbow's subsonic speed meant it could not get far enough ahead of the bomber to be useful. Asupersonic development, the Longbow, was under development, but ultimately cancelled as well.
The role was finally filled by theAGM-28 Hound Dog, a much larger supersonic missile. The Hound Dog served the dual purpose of attacking defense sites as well as being astand-off missile to use against strategic targets so that the bombers did not have to approach them. However, Hound Dog was so large that only two could be carried by aB-52, and only if it removed all other weapons. A more practical system specifically for the counter-defense role was highly desirable.
The requirement for the weapon was issued by the Strategic Air Command in 1964, and the resultantAGM-69A SRAM contract was awarded to Boeing in 1966.[1] After delays and technical flaws during testing,[2] it was ordered into full production in 1971 and entered service in August 1972.[3] It was carried by theB-52,FB-111A, and, for a very short period starting in 1986, byB-1Bs based atDyess AFB inTexas. SRAMs were also carried by the B-1Bs based atEllsworth AFB inSouth Dakota,Grand Forks AFB inNorth Dakota, andMcConnell AFB inKansas up until late 1993.
SRAM had aninertial navigation system as well as aradar altimeter which enabled the missile to be launched in either asemi-ballistic or terrain-following flight path. The SRAM was also capable of performing one "major maneuver" during its flight which gave the missile the capability of reversing its course and attacking targets that were behind it, sometimes called an "over-the-shoulder" launch. The missile had acircular error probable (CEP) of about 1,400 feet (430 m) and a maximum range of 110 nautical miles (200 km). The SRAM carried theW69 warhead with an estimated yield of 170 to 200 kilotonnes of TNT (710 to 840 TJ).[4]
The SRAM missile was completely coated with 0.8 in (2.0 cm) of soft rubber, used to absorb radar energy and also dissipate heat during flight. The three fins on the tail were made of aphenolic material, also designed to minimize any reflected radar energy. All electronics, wiring, and several safety devices were routed along the top of the missile, inside a raceway.
On the B-52 SRAMs were carried externally on two wing pylons (six missiles on each pylon) and internally on an eight-round rotary launcher mounted in the bomb bay; maximum load-out was 20 missiles. Each of the B-1B's 3 internal stores bays could each contain a rotary launcher capable of holding up to 8 missiles, for a maximum loadout of 24 missiles. The smaller FB-111A could carry two missiles internally and four more missiles under the aircraft's swing-wing. The externally mounted missiles required the addition of a tailcone to reduce aerodynamic drag during supersonic flight of the aircraft. Upon rocket motor ignition, the missile tailcone was blown away by the exhaust plume.
About 1,500 missiles were built at a cost of about$592,000 each by the time production ended in 1975. TheBoeing Company sub-contracted with theLockheed Propulsion Company for the propellants, which subsequently closed with the end of the SRAM program.
An upgradedAGM-69B SRAM was proposed in the late 1970s, with an upgraded motor to be built byThiokol and aW80 warhead, but it was cancelled by PresidentJimmy Carter (along with theB-1A) in 1978. Various plans for alternative guidance schemes, including ananti-radar seeker for use against air defense installations and even a possibleair-to-air missile version, came to nothing.
A new weapon, theAGM-131 SRAM II, began development in 1981, intended to arm the resurrected B-1B, but it was cancelled in 1991 by PresidentGeorge Bush, along with most of the U.S. Strategic Modernization effort (includingPeacekeeper Mobile (Rail) Garrison,Midgetman small ICBM andMinuteman III modernization) in an effort by the U.S. to ease nuclear pressure on the disintegratingSoviet Union.
In June 1990, Defense SecretaryDick Cheney ordered the missiles removed from bombers on alert pending a safety inquiry.[5][6] A decade earlier in September 1980, A B-52H on alert status at Grand Forks AFB in northeastern North Dakota experienced a wing fire that burned for three hours, fanned by evening winds of 26 mph (42 km/h). The wind direction was parallel to the fuselage, which likely had SRAMs in the main bay. Eight years later, weapons expertRoger Batzel testified to a closedU.S. Senate hearing that a change of wind direction could have led to a conventional explosion and a widespread scattering of radioactiveplutonium.[7]
The AGM-69A was retired in 1993 over growing concerns about the safety of its warhead and rocket motor. There were serious concerns about the solid rocket motor, when several motors suffered cracking of the propellant, thought to occur due to the hot/cold cycling year after year. Cracks in the propellant could cause catastrophic failure once ignited.
