Thor (rocket family)

The Thor (PGM -17 Thor) was developed in the USA and produced single-stage medium range ballistic missile ( Intermediate Range Ballistic Missile, short IRBM ). It was powered by liquid oxygen and RP -1, a Kerosinart. She had a length of 19.8 meters and a diameter of 2.44 meters. The launch mass was 49,900 kg ( before ignition ).


The development of the Thor began in 1954 with studies for a missile with 2400 km range, one of the requirements was that these should fit in a C -124 transporter. The development contract for the Thor rocket was signed with the Douglas Aircraft Company in December 1955. The development ended in July 1956, the first production model of the Thor missile was Florida delivered to the U.S. Air Force (USAF ) at the Cape Canaveral Air Force Station. The tests were conducted 11 months. Had the Thor missile program so that the shortest test period from the idea through to handover to a U.S. missile program.

The first four Thor test starts ( as of 25 January 1957) were failures. After these early failures, followed by intensive studies with several subsequent successful launches. The rocket went into the active component of the USAF in September 1958, so she was the world's first commissioned in IRBM ( intermediate-range missile).

The Thor 1959 declared operational and assigned to the Strategic Air Command. The rocket was also erected 1959-1963 in the UK, where she was the Royal Air Force assumed.

With the development of better missiles, the Thor was retired in 1963 as a weapons system.

Use as a launcher

Already in the early stages of development it was noticed that the Thor is well suited as a basis for a satellite launcher. The first launch of the Thor role in a launch vehicle took place on April 23, 1958 instead of (local time ), but ended with an explosion. Then it was further used extensively for space, where they later formed the basis for the Delta family. The Thor rocket as first stage rocket was used with different upper stages to launch different payloads:

  • Thor Able: Thor with the upper stage of the Vanguard rocket, 1958 ( false start ) Last Run started, for example, early space probes Pioneer type, first start April 23, April 1, 1960, a total of 16 starts Thor Able with Vanguard second stage
  • Thor Able I with Altair solid engine as a third stage
  • Thor Able II / III / IV compared with the deflection in each case further improved second-stage engines
  • Thor Able II M1 is a deflection II with Altair solid engine as a third stage
  • Thor Able -Star: version with greatly enlarged fuel capacity of the upper
  • Thor Able - Star 2: Version with improved first stage ( Thor Thor DSV 2A instead of DM 21 )
  • Thor Agena A: with Agena upper stage of the Atlas rocket, first start January 21, 1959, last start September 13, 1960
  • Thor Agena B: Version started with doubled fuel capacity and slightly improved engine Bell 8061 Bell 8069 or later, first start October 26, 1960, last start May 15, 1966, 45 times including 9 false starts
  • Thor Agena D: standardized version of the Agena B for different payloads, first start June 28, 1962, last start January 17, 1968
  • Thrust Augmented Thor Agena B / D: amplified with three 1 Castor solid rocket thrust on the skeleton of the Erststufentriebwerkes Thor Agena B / D
  • Thor Burner 1: with Star 20 solid propellant
  • Thor Burner 2: With Star 37 solid propellant as a second stage and Star 13 solid propellant as a third stage
  • Thor Burner 2A: with Star 37B solid drive as a second stage and Star 26B solid-propellant third stage as

The Thor Agena and Thor Delta were reinforced with three additional small auxiliary rockets to increase performance. So it was almost twice as strong as the original Thor.

The Long Tank Thor ( Thorad Agena D SLV 2G and 2H) was an extended version of the Thor first stage, which started the first time in summer 1966. You could hold 20 % more fuel, and thus had a length of 21.5 meters. The diameter also was 2.44 meters. It was total times (with 2 false starts ) for the start of military Keyhole and some civilian satellites used between August 9, 1966, the May 25, 1972 43 (eg OGO 6). The payload was 2 tons into low orbit.

1960 was the first Thor - Delta, an improved Thor missile launched. The name was officially shortened to Delta, to distinguish them from the military variations that still bore the name of Thor.

From Air Force Base Vandenberg this rocket was launched until 1972, when she brought both military and civilian satellite into orbit.


Basis of all the Thor missile is the first stage of the ICBM. This is LR79 -NA -9 equipped with a hydraulically pivotable about two axes Rocketdyne (also known as SD-3 and MB -3 ) having 760 kN vacuum boost, which was used in the Atlas of Juno II. In addition, 2 smaller vernier engines of the type LR -102 provide each with 4.54 kN thrust and by 6 ° inclined nozzles for roll control. The fuel tanks (oxygen tank below, kerosene tank top) were assembled in each of two half shells which had a wall thickness of 6.35 mm thickness. For this first stage launchers with various upper stages, for example, the deflection, various versions of Agena and, later, the upper stages of the Vanguard has been added. This created a variety of versions from which then the later Delta rocket was.


The first stage of today's Delta II is still a Thor version. They called Thor XLT (Extra Extended Long Tank ). This has been so extended to the tank magnification that the Delta II can not stand in refueled state without the solid rocket boosters.