RAF Thor IRBM - Deployed 1959-63

Thor was the United States's first operational ballistic missile.

Also see Thor (rocket)

Fearful that the Soviet Union would deploy a long-range ballistic missile before the United States, in January 1956 the Air Force began developing the Thor, a 1,500~mile intermediate-range ballistic missile (IRBM). The Thor program unfolded with amazing speed, and within 3-years of the program’s inception the first Thor squadron became operational in Great Britain. The Thor was a stop-gap measure, however, and once the first generation of ICBMs based in the United States became operational, the Thor missiles were quickly retired. The last of the missiles was withdrawn from operational alert in 1963.

System Operation

All sixty of the Thor missiles deployed in Great Britain were based at above-ground launch sites. The missiles were stored horizontally on transporter-erector trailers and covered by a retractable missile shelter. To fire the weapon, the crew electronically rolled back the missile shelter and then, using a powerful hydraulic launcher-erector, lifted the missile to an upright position. Once it was standing on the launch mount, the missile was fueled and fired. The entire launch sequence took about 15 minutes. When the launch control officer pressed the firing button, the main engine ignited with a roar. It burned for almost 2l/2 minutes, boosting the missile to a speed of 14,400 feet per second. Ten minutes into its flight the missile reached an altitude of 280 miles, close to the apogee of its elliptical flight path. At that point the reentry vehicle separated from the fuselage and began its descent down toward the target. Total flight time from launch to impact: 18 minutes.

Specifications

Popular Name: Thor.

Type: Intermediate range ballistic missile.

IOC: 1958. Year: 1958.

Family: Thor IRBM, Thor DM-18 (single stage LV); Thor DM-19 (rocket 1st stage), Thor DM-21 (rocket 1st stage), Thor DSV-2D,E,F,G (suborbital LV), Thor DSV-2J (anti-ballistic missile), Thor DSV-2U (orbital launch vehicle).

Country: USA. Department of Defense

Designation: PGM-17A.

Alternate Designation: SM-75.

Also PTM-17A, USM-75

Manufacturer: Douglas Aircraft Company

Thrust (vac): 77,367 kgf.

Liftoff Thrust (sl): 68,000 kgf. - 150,000-lbs

Isp: 282 sec.

Isp(sl): 248 sec.

Burn time: 165 sec.

Core Diameter: 2.44 m.

Total Length: 19.82 m. - 65-ft

Span: 2.74 m. - 8-ft

Weight: 49,800-kg - 110,000-lb

Empty Weight: 3,125 kg.

Standard warhead mass: 1,000 kg.

Maximum range: 2,400 km. - 1,500-mi

Ceiling: 480 km - 300-miles

Number Standard Warheads: 1.

Standard RV: Mk. 2.

Standard warhead: W49.

Standard warhead yield: 1,440 KT.

Standard warhead CEP: 1 km.

Boost Propulsion: Liquid rocket, Lox/Kerosene.

Power plant: Main: Rocketdyne LR79-NA-9 (Model S-3D); 666 kN (150000 lb) Vernier: 2x Rocketdyne LR101-NA; 4.5 kN (1000 lb) each

Manufacturer Name: MB-1. Government Designation: LR-79-7. Designer: Rocketdyne. Developed in: 1955. Application: . Used on stages: Thor DM-19. Used on launch vehicles: Delta, Thor, Thor Able, Thor Agena A, Thor Agena B, Thor Agena D, Thor Burner. Propellants: Lox/Kerosene Thrust (vac): 77,367 kgf. Thrust (vac): 758.70 kN. Isp: 282 sec. Isp (sea level): 248 sec. Burn time: 165 sec. Mass Engine: 643 kg. Diameter: 2.44 m. Chambers: 1. Chamber Pressure: 41.00 bar. Area Ratio: 8.00. Thrust to Weight Ratio: 120.32. Country: USA. Status: Out of Production. First Flight: 1958. Last Flight: 1980. Flown: 145. Comments: Designed for booster applications. Gas generator, pump-fed.

Guidance: Inertial.

Maximum speed: 17,740 kph. - 11,000-mph

Development Cost $: 500.00 million.

Recurring Price $: 6.25 million.

Total Number Built: 224. Total

Development Built: 64.

Total Production Built: 160.

Flyaway Unit Cost $: 0.75 million. in 1958 unit dollars.

Launches: 59. Failures: 14. Success Rate: 76.27% pct. First Launch Date: 25 January 1957. Last Launch Date: 05 November 1975.

  • External Links

Thor IRBM history site