1951 in spaceflight

The Army, Air Force, and the Applied Physics Laboratory continued their use of Aerobee sounding rockets on a variety of physics, aeronomy, photography, weather, and biomedical missions. 11 total were launched during the year.[2]

The first generation of U.S. Navy built Viking sounding rockets reached its acme of performance with the flight of Viking 7, the sole Viking launch of 1951. Launched 7 August from White Sands Missile Range in New Mexico, the rocket set a new world altitude record of 136 miles (219 km).[3]^{:167–171, 236}

The R-1, the Soviet Union's first domestically built long range ballistic missile, was accepted into service in November 1950. In January 1951, cold weather testing of the R-1 for quality assurance purposes was conducted.[4]^:149,152 On June 1, production of the R-1 was centralized and transferred to a former automobile factory in Dnepropetrovsk, and that month,[5] a test series of R-1s was successfully launched to the edge of space, all landing within 5.5 kilometres (3.4 mi) of their targets. Though the R-1, a virtual copy of the now-obsolete V-2,[4]^:119 was not a particularly formidable weapon and posed virtually no threat to the West, it was invaluable in training engineers and missile crews, as well as creating a nascent rocket industry in the Soviet Union.[4]^:152–3

On 29 January 1951, dogs were carried on one of the winter test flights of the R-1.[2] This was followed in the summer by six R-1s specifically designed equipped for biomedical flights to determine if their payload dogs could survive the rigors of space travel and be recovered. Three of the missions were successful.[6]

The R-2 missile, the first Soviet design to have a separable nose cone, underwent a second test series of thirteen flights on July 1951, experiencing one failure. Accepted for operational service on 27 November 1951, [7] the design had a range of 600 kilometres (370 mi), twice that of the R-1, while maintaining a similar payload of around 1,000 kilograms (2,200 lb).[4]^:48–9

By 1950, the ballistic war-head carrying missile, which in the United States had been eclipsed by guided missile development, came back to the fore. In January 1951, the U.S. Air Force's Air Research and Development Command awarded to Consolidated Vultee the contract for Atlas, the nation's first ICBM.[8]^:59–61 The Atlas went on to become one of the key boosters in America's crewed and robotic space programs,[9]^:32–39 first orbiting a payload (SCORE (satellite)) in 1958.[8]^:153,161–2

On 15 April 1950, Wehrner von Braun and his team of German rocket engineers were transferred from Fort Bliss to Redstone Arsenal in Alabama. In 1951, Redstone was tasked with the research and development (R&D) of guided missiles as well as development and testing of free rockets, solid propellants, JATOs, and related items, thus making the Army a leading player in America's missile development.[10] There work led to the production of the Redstone missile, first launched in 1953,[11] versions of which launched America's first artificial satellite, in 1958, and America's first astronaut, in 1961.

In the summer of 1950, the NRL team led by Milton Rosen began work on an improved Viking rocket able to reach higher altitudes. Increased performance would be achieved through larger fuel tanks and reduced weight elsewhere on the rocket. Originally planned for launch in 1951, development of the second generation Viking took two years, and the first of the new rockets did not launch until 6 June 1952.[3]^{:172–3, 236}

In January 1951, Dr. James Van Allen, instrumental in the development of the Aerobee rocket, joined the physics department at the University of Iowa (UoI). Along with University of Chicago graduate, Melvin B. Gottlieb, and Van Allen's first UoI graduate student, Leslie H. Meredith, they began a high altitude cosmic ray research program using equipment mounted on balloons. Launched from 16 June 1965 though 26 January 1952,[12]^:7–10 this experience set the foundation for balloon-launched sounding rockets, which would first breach the boundary of space in 1954.[12]^:38

From 1947, the German émigré-designed G-1 (or R-10) had competed with the Russian-designed R-2 for limited engineering and production staff, the latter winning out by the end of 1949. With the project stalled for lack of resources and government interest, all work by the German specialists was terminated on October 1950. In December 1951, the first of the specialists were repatriated to East Germany (a process that was completed November 1953)[4]^:69–70

The draft plan for the ambitious 3,000 kilometres (1,900 mi) range R-3 was approved on 7 December 1949,[4]^:67 but was canceled on 20 October 1951, other designs proving more useful and achievable.[4]^:275–6 One of them was the R-5 missile, able to carry the same payload as the R-1 and R-2 but over a distance of 1,200 kilometres (750 mi)[4]^:242 (the other being the R-11, a tactical missile half the size of the R-1 but with the same payload).[13] The R-5's conceptual design was completed by 30 October 1951.[14]^:97