Viking was a series of twelve sounding rockets designed and built by the Glenn L. Martin Company under the direction of the US Naval Research Laboratory (NRL). Designed to supersede the German V-2 as a research vehicle, the Viking was the most advanced large, liquid-fueled rocket developed in the United States in the late 1940s, providing much engineering experience while returning valuable scientific data from the edge of space between 1949 and 1955.
After twelve flights, the Viking was adapted into the first stage for the Vanguard satellite launch vehicle, which launched America's second satellite into orbit in 1958.
Origins
After World War II, the United States Army experimented with captured German V-2 rockets as part of the Hermes program. The number of V-2s available for all research was limited and Hermes was an Army project. The US Navy had the need to develop advanced missiles for both weapons and research purposes. The US Navy issued a contract 21 August 1946 to the Glenn L. Martin Company for a series of 10 large liquid-fueled rockets. The intent was to provide an independent US capability in rocketry, and to provide a vehicle better suited to scientific research. Originally dubbed "Neptune," it was renamed "Viking" in 1947 to avoid confusion with the Lockheed P-2 Neptune. The Viking was the most advanced large, liquid-fueled rocket being developed in the US at the time.
Design
thumb|180px|left|Diagram showing both Viking rocket variants, Vikings 1 to 7 (left) and 8 to 12 (right).
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 <!-- bold because XLR10 redirects here --> engine was the largest liquid-fueled rocket engine developed in the United States up to that time, producing of thrust at sea level, and in a vacuum. The specific impulse was and respectively, with a mission time of 103 seconds. 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. XLR-10-RM-2 was regeneratively cooled. On 10 May 1950, from a site in the Pacific Ocean between Jarvis Island and Kiritimati, the fourth Viking became the only Viking rocket sounding rocket ever launched from a sea-going vessel. The flight was perfect, reaching , more than double that reached by Vikings 1 and 3. Viking 8, from White Sands Missile Range in New Mexico. The new Viking design was nearly half as wide again as its precursor, affording the highest fuel-to-weight ratio of any rocket yet developed. The tail fins no longer supported the weight of the rocket, as had previously been the case. Now, the Viking rocket rested on the base of its fuselage. This allowed the tail fins to be made much lighter, allowing the rocket to carry a heavier tank without weighing more than the first Viking design.
On 6 June 1952, Viking 8 broke loose of its moorings during a static firing test. After it was allowed to fly for 55 seconds in the hope that it would clear the immediate area and thus pose no danger to ground crew, Nat Wagner, head of the "Cutoff group", delivered a command to the rocket to cease its thrust. 65 seconds later, the rocket crashed downrange to the southeast.
thumb|Viking 12 reconstruction at the Smithsonian|alt=Viking 12 reconstruction at Smithsonian
Parts of Viking 12 were recovered and, along with parts built from the original blueprints, were used to create a full-size cutaway reconstruction of the rocket. This vehicle was donated by the Martin Marietta Corp in 1976 to the National Air and Space Museum, where it is on display.
Viking into Vanguard
The Viking series returned a bonanza of scientific information measuring temperature, pressure, density, composition and winds in the upper atmosphere and electron density in the ionosphere, and recording the ultraviolet spectra of the Sun,
In October 1952, the General Assembly of the International Council of Scientific Unions (ICSU) adopted a proposal to undertake simultaneous observations of geophysical phenomena over the entire surface of the Earth. The International Geophysical Year (IGY), set for 1957–58, would involve the efforts of a multitude of nations in such farflung regions as the Arctic and Antarctica. In January 1955, Radio Moscow announced that the Soviet Union might be expected to launch a satellite in the near future. This announcement galvanized American space efforts; in the same month, the National Academy of Sciences' IGY committee established a Technical Panel on Rocketry to evaluate plans to orbit an American satellite. combined with upper stages to put a satellite into orbit, which could be tracked optically.,
Table of flights
{| class="wikitable sortable"
|+Viking flights
! width="100" |Viking #
! width="130" |Launch date
! width="100" |Altitude
! Remarks
|-
| 1
| 3 May 1949
|
| Prolonged and trying period of ground firing tests. Altitude limited by premature engine cut-off traced to steam leakage from the turbine casing. Vikings 13 and 14 were launched from Cape Canaveral.