Encyclopedia Astronautica
Thor Able

Thor Able
Credit: © Thomas Kladiva - Thomas Kladiva
Thor Able 2
Credit: © Thomas Kladiva - Thomas Kladiva
Credit: US Air Force
Thor Able
Thor Able - COSPAR 1959-004
Thor Able
Thor Able-Star - COSPAR 1960-013
Thor Able
Thor Able - 58
Thor Able
Credit: © Mark Wade
American orbital launch vehicle. Thor with Able stage derived from Vanguard second stage.

In October 1957, Paul Degarabedian, an Associate Manager at Space Technology Laboratories (later TRW), proposed an American lunar/interplanetary launch vehicle combining the Air Force Thor IRBM; with the second and third stages of the Navy's Vanguard satellite launcher. This idea didn't make it past his management, but a month later he proposed a two stage Thor Vanguard, which he called the Thor A or Able, for test of subscale models of ICBM warheads. This was of interest, and within a month an order was placed with Aerojet for several Vanguard second stages. The STL team used the Thor's own guidance system, and built the payload interface compartment and ejection actuators in-house. It was also necessary to add 84 kg of ballast to prevent the two-stage missile's payload from overshooting its south Atlantic impact area and hitting Africa. STL Electronic Laboratory's George Mueller, later a key NASA manager in the Apollo program, was made project manager of the $1.55 million classified program. The first tests of the Aerojet Able stage began on February 21, 1958. The first Thor stage arrived on March 4. It was decided that the nosecones would carry an instrumented mouse to see if it could survive boost, sustained zero-G, and re-entry. Three weeks later the integrated tests were completed and the booster was declared ready for flight - only four months after it was conceived!

The first launch attempt on April 23 ended at T+146 when the Thor exploded due to a turbopump main bearing failure, and mouse Mia (inauspiciously named 'Missing In Action') perished. The same problem had occurred on other Thors and it took a while to identify the cause, take corrective action, and fix the turbopumps in the field. The second launch on July 9, with a ballistic nosecone and the Mouse Mia II aboard, was successful, although the nosecone could not be located by the recovery ship before it sank.

On the third launch, on July 23, telemetry indicated that mouse Wickie survived the flight into space through splashdown. But again the nosecone was not located. This completed the nosecone tests. In February it had been suggested that the configuration could be converted into a low-cost ICBM, dubbed Thoric (Thor Inter-Continental). This was an obvious threat to the Atlas program and got nowhere.

Thor B or Thor Baker was to use the three-stage combination originally proposed in October 1957 to allow the Air Force to send the first space probe to the moon. It was renamed Thor Able-I and the first launch attempt on August 17 was thwarted when the first stage failed at T+70 seconds. The next month NASA took over the program, and the Thor Able-I's payloads became the first of NASA's long series of Pioneer deep-space probes. The USAF used an upgraded version of the Aerojet Able stage for another series of reentry vehicle tests in 1959, while NASA and DARPA continued to use developed versions of the rocket for launch of Explorer, Transit, and Tiros satellites. Finally the addition of solid rocket boosters allowed larger upper stages to be carried and payload to be increased in the Delta series of rockets. The evolutionary descendant of the Thor Able, the Delta 7000, was still flying in the 21st Century. Payload had increased from 100 kg to over 5 tonnes, and the Delta was the most reliable and economical launch vehicle ever produced in the United States.

LEO Payload: 120 kg (260 lb) to a 640 km orbit at 48.00 degrees. Failures: 1. First Fail Date: 1958-04-24. Last Fail Date: 1958-04-24 in 1985 dollars. Flyaway Unit Cost $: 8.930 million.

Stage Data - Thor Able

  • Stage 1. 1 x Thor DM-19. Gross Mass: 49,340 kg (108,770 lb). Empty Mass: 3,125 kg (6,889 lb). Thrust (vac): 758.711 kN (170,565 lbf). Isp: 282 sec. Burn time: 165 sec. Isp(sl): 248 sec. Diameter: 2.44 m (8.00 ft). Span: 2.44 m (8.00 ft). Length: 18.42 m (60.43 ft). Propellants: Lox/Kerosene. No Engines: 1. Engine: LR-79-7. Status: Out of Production.
  • Stage 2. 1 x Able. Gross Mass: 2,268 kg (5,000 lb). Empty Mass: 816 kg (1,798 lb). Thrust (vac): 34.300 kN (7,711 lbf). Isp: 270 sec. Burn time: 115 sec. Isp(sl): 240 sec. Diameter: 0.84 m (2.75 ft). Span: 0.84 m (2.75 ft). Length: 6.57 m (21.55 ft). Propellants: Nitric acid/UDMH. No Engines: 1. Engine: AJ10-101. Status: Out of Production.

Status: Retired 1958.
Gross mass: 51,608 kg (113,776 lb).
Payload: 120 kg (260 lb).
Height: 30.00 m (98.00 ft).
Diameter: 2.44 m (8.00 ft).
Thrust: 667.20 kN (149,993 lbf).
Apogee: 640 km (390 mi).
First Launch: 1958.04.24.
Last Launch: 1958.07.23.
Number: 4 .

More... - Chronology...

Associated Countries
Associated Spacecraft
  • Pioneer 0-1-2 American lunar orbiter. 3 launches, 1958.08.17 (Pioneer (1)) to 1958.11.08 (Pioneer 2). Pioneers 0, 1 and 2 were the first U. S. spacecraft to attempt to leave Earth orbit. More...
  • S-2 American earth magnetosphere satellite. One launch, 1959.08.07, Explorer 6. First Earth photo; radiation data. More...
  • Transit American navigation satellite. 46 launches, 1959.09.17 (Transit 1A) to 1988.08.25 (Transit O-31). The Transit Navigation System began development in 1958. More...
  • Pioneer 5 American solar satellite. One launch, 1960.03.11. Pioneer 5 was designed to provide the first map of the interplanetary magnetic field. The vehicle functioned for a record 106 days, and communicated with Earth from a record distance of 36.2 million km. More...
  • TIROS American earth weather satellite. 12 launches, 1960.04.01 (Tiros 1) to 1966.02.28 (ESSA 2). TIROS spacecraft were the beginning of a long series of polar-orbiting meteorological satellites. More...

Associated Engines
  • AJ10-101 Aerojet Nitric acid/UDMH rocket engine. 34.3 kN. Isp=270s. Derivative of Vanguard second stage for use with Thor IRBM to produce satellite launch vehicle. First tests February 21, 1958. Flown through 1960. More...
  • LR79-7 Rocketdyne Lox/Kerosene rocket engine. 758.7 kN. Out of production. Designed for booster applications. Gas generator, pump-fed. Isp=282s. First flight 1957. More...

See also
  • Delta The Delta launch vehicle was America's longest-lived, most reliable, and lowest-cost space launch vehicle. Development began in 1955 and it continued in service in the 21st Century despite numerous candidate replacements. More...

Associated Manufacturers and Agencies
  • Douglas American manufacturer of rockets, spacecraft, and rocket engines. Boeing Huntington Beach, Huntington Beach, CA, USA. More...

Associated Launch Sites
  • Cape Canaveral America's largest launch center, used for all manned launches. Today only six of the 40 launch complexes built here remain in use. Located at or near Cape Canaveral are the Kennedy Space Center on Merritt Island, used by NASA for Saturn V and Space Shuttle launches; Patrick AFB on Cape Canaveral itself, operated the US Department of Defense and handling most other launches; the commercial Spaceport Florida; the air-launched launch vehicle and missile Drop Zone off Mayport, Florida, located at 29.00 N 79.00 W, and an offshore submarine-launched ballistic missile launch area. All of these take advantage of the extensive down-range tracking facilities that once extended from the Cape, through the Caribbean, South Atlantic, and to South Africa and the Indian Ocean. More...
  • Cape Canaveral LC17A Delta launch complex. Part of a dual launch pad complex built for the Thor ballistic missile program in 1956. Pad 17A supported Thor, Delta, and Delta II launches into the 21st Century. More...

Associated Stages
  • Able Nitric acid/UDMH propellant rocket stage. Loaded/empty mass 1,884/429 kg. Thrust 34.69 kN. Vacuum specific impulse 270 seconds. Engine for Vanguard was AJ10-37; for later Able models AJ10-41 and AJ10-42. Total of 21 stages built and delivered by Aerojet. More...
  • Thor DM-19 Lox/Kerosene propellant rocket stage. Loaded/empty mass 49,340/3,125 kg. Thrust 758.71 kN. Vacuum specific impulse 282 seconds. More...

Thor Able Chronology

1958 April 24 - . 00:10 GMT - . Launch Site: Cape Canaveral. Launch Complex: Cape Canaveral LC17A. LV Family: Delta. Launch Vehicle: Thor Able. LV Configuration: Thor Able 116. FAILURE: Thor turbopump gearbox failed T+150 sec.. Failed Stage: 1.
  • Able RTV re-entry vehicle test flight - . Nation: USA. Agency: USAF. Apogee: 0 km ( mi). Summary: Mouse 'Mia' not recovered..

1958 April 24 - . 00:10 GMT - . Launch Site: Cape Canaveral. Launch Complex: Cape Canaveral LC17A. Launch Vehicle: Thor Able. LV Configuration: Thor Able 116.
  • Able RTV - . Nation: USA. Apogee: 80 km (49 mi).

1958 July 10 - . 02:30 GMT - . Launch Site: Cape Canaveral. Launch Complex: Cape Canaveral LC17A. LV Family: Delta. Launch Vehicle: Thor Able. LV Configuration: Thor Able 118.
  • Able RTV re-entry vehicle test flight - . Nation: USA. Agency: USAF. Apogee: 1,600 km (900 mi). Summary: Mouse 'Mia II' reached 1600 km altitude, flew 9600 km range, but re-entry vehicle not recovered..

1958 July 23 - . 22:13 GMT - . Launch Site: Cape Canaveral. Launch Complex: Cape Canaveral LC17A. LV Family: Delta. Launch Vehicle: Thor Able. LV Configuration: Thor Able 119.
  • Able RTV re-entry vehicle test flight - . Nation: USA. Agency: USAF. Apogee: 1,600 km (900 mi). Summary: Mouse 'Wickie' not recovered; nose cone lost..

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