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by Jean-Jacques Serra
listing by Gunter Krebs

Origin: sounding rocket Viking

In 1946 the US Navy's NRL (Naval Research Laboratory) launched the study of a high performance sounding rocket named HASR-2 (High Altitude Sounding Rocket) to replace the V2s when there would be no more left. This leaded th the developement of the Neptune rocket, later renamed Viking. The Glenn L. Martin company was contacted to built 10 rockets, 4 were reordered later.

The Viking propulsion was granted to Reaction Motors which already produced the Bell X1 rocket-plane. The new motor was feed with alcohol and liquid oxygen by turbopomps. It provided 91.5 kN thrust. Names XLR-10 this motor was a high technology one at the time because it used regenerating cooling system and a deployable nozzle. The rocket also had integral tanks to lighten the structure and a 3-axis stabilization with little nozzles around the it to orient it after the shutdown of the main engine.

There are 2 generations in the Viking series: the models 1 to 7 that were 81 cm diameter and models 8 to 14 (shorter) that were 114 cm diameter. The heights were ranging from 14.8 m to 12.8 m and the takeoff weights were between 4.37 tons and 6.81 tons. Between May 1949 and May 1959 only one failure occured with Viking-8. All Vikings were launched from White Sands except Viking-4 which was launched from the deck of USS Norton Sound and the 2 last ones which where used as test vehicles for the Vanguard program, launched from Cape Canaveral.


In July 1955 the United States announced their intention of launching small earth artificial satellites as their contribution to the International Geophysical Year of 1957-1958. Two months later the Vanguard project was selected to launch those satellites.

The project was granted to the Glenn L. Martin Company which was to use a modified Viking rocket as first stage. In fact the differences were important: the diameter stayed the same but the length was extended to 13.4 m and the propulsion system was changed. This new motor built by General Electric was derived from the Hermes A-3B project. Named X-405 it used kerosene and LOX, had a deployable nozzle and provided 120 kN (A-3B: 100 kN) during 145 seconds. The X-405 had a re-generated cooling system and was powered by turbopomps.

The second stage of Vanguard was designed by Aerojet General. It was an extrapolation of the Aerobee Hi: the diameter was extended to 81 cm. The AJ-10 motor had a deployable nozzle and its thrust was then 33 kN with a lifetime of 120 s. It was feeded with a mix a stockable propellant helium-pressurized: UDMH (Unsymmetrical DiMethyl Hydrazine) and WIFNA (White Inhibited Fuming Nitric Acid). This second stage also contained the flight control equipement and the 3rd stage table rotator. During the propulsed flight phases the rocket was controled with the nozzles and during the balistic phase after the 2nd stage shutdown by helium jets.

The third stage was equipped with a 33-KS-2800 solid booster from Grand Central Rocket Company which provided 12.5 kN thrust during 33 seconds. It was replaced for the last launch by a lighter motor developped by Alleghany Ballistics Laboratories. This glass fiber reinforced platic structure X-248 Altair engine provided 13.8 kN.

Finally the Vanguard rocket weighed 21.6 m high with the cap. The payload was only of a few kilograms in the first version and reached 20 kg with the last model.

After 2 test flights with a Viking first stage (TV-0 & TV-1) in Dec 1956 & May 1957 the launch of a Vanguard first stage with mockups of the top stages (TV-2) occured in Oct 1957, a few days after the launch of Sputnik 01. The successful Russian launch cause the program to be accelerated despite reliability questions. Two failures (TV-3 & TV-3A) occured before the success of Vanguard 1 in March 1958. Four failures (TV-5 & SLV-1 to -3) occured before a success in Feb 1959. The third and last success occured in Sep 1959 after 2 more failures (SLV-5 & -6).

Three success out of 11 flights was not a good score especially because the Russian failures were keep secret. Worth to be noted the Vanguard top stages were used to design the Able (see Thor Able) and then the Delta (see Thor Delta) which were very reliable. Also the stages derived from Altair were used on several launchers ( Thor, Atlas, Scout, etc.).

Vanguard launches

# Launch id Payload Launch Date Site Status/Comment (orbit in perigee x apogee x inclination x period)
1, TV-3 FTO Vanguard 1A 6 Dec 1957 Failure: exploded after 2 s
2, TV-3BU FTO Vanguard 1B 5 Feb 1958 Failure: control lost after 57 s
3, TV-4 58002 Vanguard 1 17 Mar 1958  
4, TV-5 FTO Vanguard 2A 28 Apr 1958 Failure: 3rd stage failed to ignite
5, SLV-1 FTO Vanguard 2B 27 May 1958 Failure
6, SLV-2 FTO Vanguard 2C 26 Jun 1958 Failure
7, SLV-3 FTO Vanguard 2D 29 Sep 1958 Failure
8, SLV-4 59001 Vanguard 2 17 Feb 1959  
9, SLV-5 FTO Vanguard 3A 13 Apr 1959 Failure
10, SLV-6 FTO Vanguard 3B 22 Jun 1959 Failure
11, TV-4BU 59007 Vanguard 3 18 Sep 1959 Partial failure: 3rd stage failed to separate from payload

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