- Viking rocket
The Viking rocket series of
sounding rockets were designed and built by the Glenn L. Martin Company(now Lockheed-Martin) under the direction of the U.S. Naval Research Laboratory(NRL). A total of twelve Viking rockets flew from 1949 to 1955 ["The Viking Rocket Story", by Milton W. Rosen, Harper & Brothers, NY, 1955. Rosen, the NRL project manager for "Viking", describes the project's context, history, design, and includes chapters on all flights through Viking 11, with an outline of basic design issues for large liquid rockets, together with much interesting detail about the countless problems that inevitably arose in such an ambitious and innovative program.] .
World War IIthe United Statesexperimented with captured German V-2 rockets as part of the Hermes project. Based on these experiments the U.S. decided to develop its own large liquid fueled rocket design, to be called "Viking". The intent was both to provide an independent US capability in rocketry, to continue the Hermes project after the V-2's were expended, and to provide a vehicle better suited to scientific research. Having been designed as a weapon, the V-2 carried a large payload, approximately one ton of high explosive. This was more than was considered necessary for the scientific instrument payload of a high-altitude research rocket, but in the case of the V-2, most of it was also required for stable flight ["Rockets, Missiles, and Space Travel", by Willey Ley, 3rd Edition, Viking Press, New York, 1951, p. 250ff.] , limiting the potential speed and altitude that could be reached with the smaller payloads typically needed for early scientific investigations.
The Viking was roughly half the size, in terms of mass and power, of the German V-2, with which it had many similarities. Both were actively guided rockets, fueled with the same propellants (alcohol and liquid oxygen [LOX] ), which were fed to a single large engine by turbine-driven pumps. The engine, built by Reaction Motors Inc (RMI), was the largest liquid-fueled rocket engine developed in the United States up to that time. It produced 89 kN (20000 lbf) of thrust. As was also the case for the V-2,
hydrogen peroxidewas converted to steam to drive the turbopumpthat fed fuel and LOX into the engine.
"Viking" did pioneer important innovations over the V-2. One was the use of a gimbaled motor which could be swiveled from side to side for pitch and yaw control, dispensing with the inefficient and somewhat fragile graphite vanes in the engine exhaust used by the V-2. Roll control was by use of the turbopump exhaust to power RCS jets on the fins. Compressed gas jets stabilized the vehicle after the main power cutoff. Similar devices are now extensively used in large, steerable rockets and in space vehicles. Another improvement was that initially the alcohol tank, and later the LOX tank also, were built integral with the outer skin, saving weight. The structure was also largely aluminum, saving weight from the steel used in the V-2.
Vikings 1 through 7 were slightly longer (about 15 m, 49 ft) than the V-2, but with a straight cylindrical body only 32 in (81 cm) in diameter, making the rocket quite slender. They had fairly large fins similar to those on the V-2. Vikings 8 through 14 were built with an enlarged airframe of improved design. The diameter was increased to 45 in (114 cm), while the length was reduced to 13 m (42 ft), destroying the missile's "pencil shape". The fins were made much smaller and triangular. The added diameter meant more fuel and more weight, but the "mass ratio", of fueled to empty mass, was improved to about 5:1, a record for the time.
All except Viking 4 were flown from White Sands.
The first launch, of Viking 1, on 3 May 1949 came after a very prolonged and trying period of ground firing tests, and attained an altitude of mi to km | 50 | precision = -1. The altitude was limited by a premature engine cut-off, eventually traced to steam leakage from the turbine casing.
Viking 2, flown 6 September 1949, also suffered early engine cut-off for the same reason as Viking 1; it reached only mi to km | 32 | precision = -1. (Subsequent engines had the turbine casing halves welded rather than bolted together, solving the problem.)
Viking 3, 9 February 1950, suffered from instability in a redesigned guidance system, and had to be cut off by ground command when it threatened to fly outside the range. Altitude was again only mi to km | 50 | precision = -1.
Viking 4, on 11 May 1950, launched from the deck of the
USS Norton Soundnear the Equator, reached a peak altitude of mi to km | 105 | precision = -1, almost the maximum possible for the payload flown, in a nearly perfect flight. Guidance system was reverted to that of Vikings 1 & and 2.
Viking 5, 21 November 1950 reached mi to km | 108 | precision = -1. Engine thrust was about 5% low, or altitude would have been slightly higher.
Viking 6, 11 December 1950, suffered catastrophic failure of the stabilizing fins late in powered flight, with loss of attitude control, and associated very large drag. Altitude was therefore only mi to km | 40 | precision = -1.
Viking 7, 7 August 1951, reached mi to km | 136 | precision = -1 altitude to beat the old V-2 record for a single-stage rocket. This was the highest and last flight of the original airframe design.
Viking 8. First rocket of improved airframe design, lost when it broke loose during static testing, and flew to mi to km | 4 | precision = -1 before ground commanded cut-off, 6 June 1952.
Viking 9, 15 December 1952, reached mi to km | 136 | precision = -1 altitude in the first successful flight of the improved airframe design.
Viking 10. Engine exploded on first launch attempt 30 June 1953. Rocket rebuilt and flown successfully 7 May, 1954, to mi to km | 136 | precision = -1.
Viking 11 rose to mi to km | 158 | precision = -1 on 24 May
1954, an altitude record for a Western single-stage rocket up to that time. [cite web | url = http://www.astronautix.com/lvs/viking.htm | title = Viking | publisher = Encyclopedia Astronautica] Earth photography and re-entry vehicle test.
Viking 12, flown in 4 February 1955, as for re-entry vehicle test, photography, and atmospheric research. Reached 231 km (143 mi).
Two additional Viking airframes, similar to Vikings 9 -- 12, were flown as test vehicles for Project Vanguard. Both were launched from Cape Canaveral in 1956 and 1957, and designated TV0 and TV1.
Through these Viking flights, NRL was first to measure temperature, pressure, and winds in the upper atmosphere and electron density in the ionosphere, and to record the ultraviolet spectra of the Sun. On
October 5 1954[NB date apparently in error, as Rosen, ibid, lists the Viking 11 flight as being on 24 May 1954. "Encyclopedia Astronautica" lists no flights on this date.] , during a launching from White Sands, New Mexico, a camera mounted in Viking 11 took the first picture of a hurricane and a tropical storm, from altitudes of nearly mi to km | 100 | precision = -1. The picture embraced an area more than 1600 km (1000 miles) in diameter, including Mexicoand the area from Texasto Iowa. This was also the first natural-color picture of Earth from rocket altitudes, clearly showing its curvature.
Viking into Vanguard
The success NRL achieved in this series of experiments encouraged Laboratory scientists to believe that, with a more powerful engine and the addition of upper stages, the Viking rocket could be made a vehicle capable of launching an earth satellite. This led to NRL's
Project Vanguard. Later rockets in this series, Vanguard TV0 (renamed from Viking 13) and TV1 were used as suborbital test vehicles during Project Vanguard.
* [http://www.nrl.navy.mil/content.php?P=VIKING U.S. Naval Research Laboratory]
National Air and Space Museumcontains a full-size cutaway reconstruction of Viking 12, built from original blueprints.
* [http://www.astronautix.com/lvs/viking.htm Astronautix.com]
* [http://www.postwarv2.com/viking/viking.html Begg's aerospace]
* [http://www.designation-systems.net/dusrm/app1/rtv-n-12.html Directory of U.S. Military Rockets and Missiles]
* [http://history.nasa.gov/SP-4401/sp4401.htm NASA sounding rockets, 1958-1968]
* [http://www.nielspapermodels.com/models.htm Free paper models of viking 7, 10, 13 and 14]
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