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).

For the European rocket engine, see Viking (rocket engine).
Viking
Launch of Viking 10, 7 May 1954
FunctionResearch sounding rocket
ManufacturerGlenn L. Martin Company
Country of originUnited States
Size
Height49 ft (15 m)
Diameter32 in (810 mm)
Stages1
Capacity
Payload to
Launch history
StatusRetired
Launch sites
Total launches12
Success(es)7
Failure(s)1
Partial failure(s)4
First flight3 May 1949
Last flight4 February 1955
First stage
EnginesReaction Motors XLR10-RM-2
Thrust92.5 kN (20,800 lbf) (sea level) and 110.5 kN (24,800 lbf) (vacuum)
Specific impulse179.6 seconds (1.761 km/s)
Burn time103 seconds
FuelEthyl alcohol and liquid oxygen

Origins

After World War II, the United States experimented with captured German V-2 rockets as part of the Hermes project. Based on these experiments the U.S. decided in 1946 to develop its own large liquid-fueled rocket design, to be called Neptune but changed to Viking. The intent was to provide an independent U.S. capability in rocketry, to continue the Hermes project after the V-2s were expended, and to provide a vehicle better suited to scientific research. The Navy, in particular, needed a vehicle to study the atmosphere and learn how to predict bad weather which would affect the fleet.

The V-2 would tumble in the rarefied atmosphere at high altitudes. 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, used for research, most of the payload was lead ballast required for stable flight,[1]:250 limiting the potential speed and altitude that could be reached with the smaller payloads typically needed for early scientific investigations.

The NRL, partly at the instigation of the American Rocket Society (ARS), chose to build the advanced sounding rocket. Milton Rosen, head of the Viking project, credits rocket pioneer Robert Goddard, the ARS, the California Institute of Technology and the V-2 for the "profound influence" they had on the design of the rocket.[2]:26 Twelve Viking rockets flew from 1949 to 1955.[2]:28

The Viking was the most advanced large, liquid-fueled rocket being developed in the U.S. at the time.[3]

Design features

The Viking was roughly half the size, in terms of mass and power, of the V-2. Both were actively guided rockets, fueled with the same propellant (Ethyl alcohol and liquid oxygen), which were fed to a single large pump-fed engine by two turbine-driven pumps. The Reaction Motors XLR10-RM-2 engine was the largest liquid-fueled rocket engine developed in the United States up to that time, producing 92.5 kN (20,800 lbf) (sea level) and 110.5 kN (24,800 lbf) (vacuum) of thrust. Isp was 179.6 seconds (1.761 km/s) and 214.5 seconds (2.104 km/s) respectively, with a mission time of 103s. As was also the case for the V-2, hydrogen peroxide was converted to steam to drive the turbopump that fed fuel and oxidizer into the engine. As its V-2 counterpart, it also was regeneratively cooled.[4][5]

Viking pioneered important innovations over the V-2. One of the most significant for rocketry was the use of a gimbaled thrust chamber which could be swiveled from side to side on two axes for pitch and yaw control, dispensing with the inefficient and somewhat fragile graphite vanes in the engine exhaust used by the V-2. The rotation of the engine on the gimbals was controlled by gyroscopic inertial reference; this type of guidance system was invented by Robert Goddard, who had partial success with it before World War II intervened.[2]:66 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, as opposed to steel used in the V-2, thus shedding more weight.

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 (810 mm) 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), altering 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.

Flight history
Diagram showing both Viking rocket variants, Vikings 1 to 7 (left) and 8 to 12 (right)
Viking # Launch date Altitude Remarks
Viking 1 3 May 1949 50 miles (80 km) Prolonged and trying period of ground firing tests. Altitude limited by premature engine cut-off traced to steam leakage from the turbine casing.
Viking 2 6 Sep 1949 32 miles (51 km) Early engine cut-off for same reason as Viking 1. Solved by welding rather than bolting turbine casing halves of subsequent engines.
Viking 3 9 Feb 1950 50 miles (80 km) Suffered from instability in a redesigned guidance system; had to be cut off by ground command when it threatened to fly outside launch range.
Viking 4 11 May 1950 105 miles (169 km) Launched from the deck of the USS Norton Sound near the Equator, almost the maximum possible for the payload flown, in a nearly perfect flight. Guidance system had been reverted to that of Vikings 1 and 2.
Viking 5 21 Nov 1950 108 miles (174 km) Engine thrust was about 5% low, slightly reducing maximum altitude.
Viking 6 11 Dec 1950 40 miles (64 km) Suffered catastrophic failure of the stabilizing fins late in powered flight causing loss of attitude control, which created very large drag and reduced maximum altitude.
Viking 7 7 Aug 1951 136 miles (219 km) Beat the old V-2 record for a single-stage rocket. Highest and last flight of the original airframe design.
Viking 8 6 June 1952 4 miles (6.4 km) First rocket of improved airframe design; lost when it broke loose during static testing, flying to just 4 miles (6.4 km) before ground commanded cut-off.
Viking 9 15 Dec 1952 135 miles (217 km) First successful flight of the improved airframe design.
Viking 10 7 May 1954 136 miles (219 km) Engine exploded on first launch attempt, 30 June 1953. Rocket was rebuilt and flown successfully.
Viking 11 24 May 1954 158 miles (254 km) Set altitude record for a Western single-stage rocket up to that time.[6]
Viking 12 4 Feb 1955 144 miles (232 km) Re-entry vehicle test, photography, and atmospheric research.

[2]:236

All except Viking 4 were flown from White Sands, New Mexico.

Achievements
Launch of Viking 4 from the USS Norton Sound at sea, 11 May 1950

While the underlying motivation for the Viking Project clearly had a national defense component, since it was a US Navy program, it nevertheless established a number of early space exploration landmarks, some technological and some scientific.

Peaceful space travel and space exploration were clearly important objectives that energized many of the higher level instigators even of the German V-2 rocket program, which was funded by the German Army entirely for military purposes. Viking was probably the most ambitious program up to its time, which had significant objectives that were essentially scientific, accompanied by a desire to explore and advance rocket technology for more ambitious peaceful space exploration goals such as artificial earth satellites.[2]:230–235

Technological advances pioneered by Viking included the following:

  • An essentially all-aluminum airframe, with a mass ratio (fueled mass to empty vehicle mass) of about 5:1 for the improved (Viking 8 and later) model. This was a significant improvement over the V-2, which was largely constructed of steel. The altitude records achieved by Viking, for a single-stage rocket, were mostly the result of its light-weight structure.
  • Thrust vector control by gimbaling the rocket motor, as opposed to the graphite vanes used by the German V-2 and the U.S. Army Redstone missiles. This method of control has become standard since, both for reliability and efficiency reasons.
  • Control of the vehicle's orientation, after fuel exhaustion of the main engine, by small auxiliary jets, permitting programmed pointing of scientific instruments, etc.
  • Extensive radio telemetry for both engineering and scientific data, which greatly reduced the number of test flights needed before useful results were obtained.

Among its scientific achievements, firsts up to their time, were:

  • The highest altitude measurement of atmospheric density (by Viking 7).
  • The highest altitude measurement of atmospheric winds (Viking 7).
  • The first measurements of the atmospheric positive ion composition at high altitude (Viking 10).
  • The highest altitude exposures of cosmic-ray emulsions (Vikings 9, 10, and 11).
  • The highest altitude photographs of the Earth (Viking 11).

Through the Viking flights, NRL was first to measure temperature, pressure, density, composition and winds in the upper atmosphere and electron density in the ionosphere, and to record the ultraviolet spectra of the Sun.[2]:234

Viking into Vanguard

The success NRL achieved in this series of experiments suggest 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. The Viking was thus incorporated as the first stage of NRL's three-stage Project Vanguard vehicle which launched the second US satellite. Two later rockets in the Viking series, Vanguard TV0 (renamed from Viking 13) and Vanguard TV1, substantially similar to Vikings 8 through 12, were used as suborbital test vehicles during Project Vanguard, before the first Vanguard vehicle, Vanguard TV2, became available for test in the fall of 1957.[7] and were designated Vanguard TV0 and Vanguard TV1 respectively.

Legacy and Status

The National Air and Space Museum contains a full-size cutaway reconstruction of Viking 12, built from original blueprints.[8]

See also

References
  1. Willy Ley (June 1951). Rockets, Missiles, and Space Travel. Dominion of Canada: Viking Press. OCLC 716327624.
  2. Milton W. Rosen (1955). The Viking Rocket Story. New York: Harper & Brothers. OCLC 317524549.
  3. "History of Rocketry & Space Travel," revised edition, Wernher von Braun and Frederick I. Ordway III, Thomas Y. Crowell Co., New York, 1969, p. 151
  4. "U.S. space-rocket liquid propellant engines". www.b14643.de. Archived from the original on 2015-11-01. Retrieved 2015-06-24.
  5. Winter, Frank H. (1990). "3 — Rockets Enter the Space Age". Rockets Into Space. Harvard University Press. p. 66. Retrieved 2015-06-24.
  6. "Viking". Encyclopedia Astronautica.
  7. Ordway, Frederick I. ; Wakeford, Ronald C. International Missile and Spacecraft Guide, N.Y., McGraw-Hill, 1960, p. 208.
  8. "Viking Sounding Rocket". National Air and Space Museum. Retrieved 5 Dec 2020.

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