Skybolt Credit - via Andreas Parsch

Air-to-surface missile. IOC: 1963. Family:

American strategic air-to-surface ballistic missile, development started in 1960. Program cancelled amid huge controversy in 1963 after Britain had agreed to buy the weapon in place of its own Blue Streak.

Historical Essay © Andreas Parsch

Douglas GAM-87/AGM-48 Skybolt

After studies in 1958 had shown that it was feasible to air-launch ballistic missiles from high-flying strategic bombers, the USAF issued a requirement in 1959 for a long-range ALBM (Air-Launched Ballistic Missile). In May 1959, Douglas was awarded a development contract for the WS (Weapons System) 138A missile, designated GAM-87 Skybolt. Douglas subsequently awarded development subcontracts to Nortronics (guidance system), Aerojet General (propulsion), and General Electric (reentry vehicle). The GAM-87 was intended for use by the B-52H Statofortress and the British Vulcan B.2. Full-scale development was approved in February 1960, and in January 1961, the first drop tests of unpowered Skybolts occurred. Powered and guided flight tests of XGAM-87A prototypes began in April 1962, but the first five tests were all failures. The first fully successful Skybolt flight occurred on 19 December 1962, but on that same day the whole program was cancelled and the production of the operational GAM-87A stopped. Although Skybolt certainly had its technical difficulties and was well behind schedule, the cancellation was also very much influenced by economical and political factors.

The XGAM-87A was ballistic missile powered by a two-stage solid-fuel rocket motor and guided by a stellar-inertial navigation system. Each B-52H was to carry four GAM-87As, two each side-by-side on two underwing pylons. While on the pylon, the Skybolt was fitted with a tail cone to reduce aerodynamic drag. For launch, the missile was dropped from the pylon, the tail cone was ejected, and the first motor stage ignited. After first stage burnout, the Skybolt coasted for a while before the second stage ignited. First stage control was by movable tail fins, while the second stage was equipped with a gimballed nozzle.

Limited flight tests with the remaining XGAM-87A missiles continued after program cancellation, and in June 1963, the XGAM-87A was redesignated as XAGM-48A. In total, Douglas built less than 100 Skybolt missiles.

Note: Data given by several sources show slight variations. Figures given below may therefore be inaccurate!

Data for XGAM-87A (XAGM-48A):

[1] Bill Gunston: "The Illustrated Encyclopedia of Rockets and Missiles", Salamander Books Ltd, 1979
[2] Dennis R. Jenkins, Brian Rogers: "Boeing B-52G/H Stratofortress", Aerofax, 1990

Manufacturer: Douglas. Launches: 6. Failures: 5. Success Rate: 16.67%. First Launch Date: 1962-04-19. Last Launch Date: 1962-12-22. Launch data is: incomplete. Apogee: 20 km (12 mi). Liftoff Thrust: 111.000 kN (24,953 lbf). Total Mass: 4,530 kg (9,980 lb). Core Diameter: 1.10 m (3.60 ft). Total Length: 11.74 m (38.51 ft). Span: 2.13 m (6.98 ft). Maximum range: 1,610 km (1,000 mi). Boost Propulsion: Solid rocket. Guidance: Inertial. Maximum speed: 8,060 kph (5,000 mph). Development Cost $: 440.000 million. in: 1962 average dollars.

• Stage1: 1 x Skybolt ALBM-1. Gross Mass: 2,000 kg (4,400 lb). Motor: 1 x Skybolt. Thrust (vac): 111.000 kN (24,953 lbf). Length: 7.00 m (22.90 ft). Diameter: 0.89 m (2.91 ft). Propellants: Solid.

• Stage2: 1 x Skybolt ALBM-2. Gross Mass: 800 kg (1,760 lb). Motor: 1 x Skybolt 2. Length: 3.00 m (9.80 ft). Diameter: 0.89 m (2.91 ft). Propellants: Solid.

1962 April 19 - AMR DZ -. Skybolt ALBM 20025 FAILURE: Failure. Test mission Agency: USAF. Apogee: 10 km (6 mi).

1962 June 29 - AMR DZ -. Skybolt ALBM 20026 FAILURE: Failure. No burn test Agency: USAF. Apogee: 12 km (7 mi).

1962 September 13 - AMR DZ -. Skybolt ALBM 20027 FAILURE: Failure. Test mission Agency: USAF. Apogee: 10 km (6 mi).

1962 September 25 - 14:09 GMT - AMR DZ -. Skybolt ALBM 20028 FAILURE: Failure. Test mission Agency: USAF. Apogee: 15 km (9 mi).

1962 November 28 - 18:45 GMT - AMR DZ -. Skybolt ALBM 20031 FAILURE: Failure. Test mission Agency: USAF. Apogee: 10 km (6 mi).

1962 December 22 - 14:15 GMT - AMR DZ -. Skybolt ALBM 20032 Test mission Agency: USAF. Apogee: 580 km (360 mi).