1956 in spaceflight

Preparation for the 18-month International Geophysical Year (IGY), scheduled to begin July 1957, became a truly international endeavor in 1956. The American IGY satellite program, Project Vanguard, saw its first test launch at the end of the year, while the Army Ballistic Missile Agency tested Redstone-derived rockets, culminating in the Jupiter-C capable of orbiting a satellite. The Soviet Union developed the engines and tested vital components for its first ICBM, the R-7 Semyorka, which would fly the USSR's first artificial satellite, "Object D:

Japan developed the Kappa 1 sounding rocket with an eye toward an advanced version that would fly during the IGY, and Canada, with the assistance of the United States, established a sounding rocket range in Churchill, Manitoba. In Italy, Rome hosted the Seventh International Aeronautical Congress, which saw 400 delegates from the scientific community and representatives of (mostly American) industry gather to discuss the technical aspects of spaceflight.

Both superpowers conducted a multitude of sounding rocket flights, probing the upper atmosphere with increasing sophistication and cadence. In addition, the Soviets completed a series of capsule launches, each with two dog passengers—a prelude to human missions in space.

The primary sounding rocket of the United States for 1956 was the Aerobee in a variety of models. Launched mostly (but not exclusively) from sites in New Mexico, missions were conducted by a myriad of agencies, both military and civilian, to probe and return information about the upper atmosphere. The University of Michigan utilized the Nike-Cajun sounding rocket, launched from the USS Rushmore in the Labrador Sea, to conduct aeronomy research. The Air Force launched its X-17 rocket a number of times, mostly testing reentry vehicles for ballistic missile use.

The year saw the completion of the second series of Soviet suborbital flights with dogs as payloads. After the completion of the nine-launch series, conducted with variations of the R-1 rocket, the results were published as "Vital Activity of Animals during Rocket Flights into the Upper Atmosphere" in December 1956 at an international conference in Paris. These flights made it clear that advanced animals could survive the rigors of space launch, reentry, and weightlessness. They also tested spacesuits, parachute recovery of space travelers, and radio telemetry.^[1]: 21

Also completed this year was the second series of Academik flights, which involved 18 sounding rocket launches between 1953 and 1956. These missions returned scientific data on cosmic rays, the atmosphere, the content and temperature of the ionosphere as well as information useful to engineers: winds, temperature, pressure and radio wave propagation at high altitudes.^{[1]: 15, 19}

Organized by the Italian rocket society under the auspices of the International Astronautical Federation, it was held 17-22 September^[2] at the Palazzo dei Congressi, 15 km (9.3 mi) from Rome. 400 delegates from astronautical societies and research institutes, as well as representatives of (mostly American) large industrial interests attended. The first day of the conference and a quarter of the 45 papers read before the conference were directly related to artificial Earth satellites.^[3]: 451

Work continued apace on Project Vanguard, the civilian satellite project initiated in fall 1955. Vanguard consisted of a tiny satellite and a rocket launcher, the latter comprising a Viking (rocket) first stage mated with two smaller rocket stages. Starting in 1956, John T. Mengel and his Naval Research Laboratory Tracking and Guiding Branch began designing the Minitrack system, a worldwide network of stations that would receive data on 108 MHz broadcast by Vanguard's tiny transmitter. In April 1946, work began on a global optical tracking network as well, whose task would be to locate the satellite in the sky so that Minitrack could maintain continuous tracking. In addition to twelve observation stations around the world, amateurs were also recruited to assist. While it would have been logistically useful to have Minitrack and optical stations at the same site, the two types of stations had different requirements--the radio stations requiring flat ground away from interference, and the visual stations needing clear skies. In the end, only Woomera in Australia had a combined tracking station.^{[4]: 146–150}

The first Vanguard test flight took place in the early morning of 8 December 1956 and involved the launch of an unmodified Viking rocket (#13). The purpose of Vanguard TV-0 was to familiarize the Vanguard team with launch operations, and to test the range safety and tracking systems at Cape Canaveral's Air Force Missile Test Center (AFMTC). TV-0 reached an altitude of 126.5 mi (203.6 km) and a range of 97.6 mi (157.1 km). 120 seconds into the flight, the rocket ejected a small sphere equipped with a Minitrack transmitter. Its broadcasts were picked up without difficulty by AFMTC's tracking stations before the little device hit the Atlantic Ocean. A post-flight evaluation conducted mid-December determined that the rocket's performance had been "either satisfactory or superior", that rocket-borne instrumentation and telemetry had been "excellent", and that ground coverage of the instrumentation had been "adequate". This successful flight paved the way for Vanguard's first multi-stage launch, scheduled for the following year.^{[4]: 170–176}

In 1956, the Army Ballistic Missile Agency (ABMA) continued trying to gain support of Project Orbiter, an Army plan to use a slightly modified Redstone (a 200 miles (320 km) range surface-to-surface missile developed the prior year)^[5] combined with upper stages employing 31 Loki solid-propellant rockets to put a 5 lb (2.3 kg) satellite into orbit, which could be tracked optically. Though Orbiter had been officially rejected the year before in favor of Vanguard, ABMA hoped Redstone-Orbiter could still be used as a backup orbital system. Reentry tests that year conducted with the newly developed, Redstone-based Jupiter-C, further strengthened ABMA confidence in their vehicle as an orbital launcher. Though Orbiter remained unapproved, late in the year the Army did authorize production and firing of 12 Jupiter-Cs for nosecone reentry tests. This set the stage for the Jupiter-C to be the de facto backup in the event of Vanguard's failure.^{[4]: 74, 199–200}

Development of an ICBM was given paramount importance by the United States government on the heels of a secret report made in February 1955 by James Rhyne Killian to the National Security Council on Soviet rocket progress. Not only was the 5,500 km (3,400 mi)-range Atlas, America's first ICBM, made the highest-priority project in the nation, but Titan, a more capable ICBM, was authorized for development as well.^[6] By late 1956, the Convair-produced Atlas was being configured for launch operations. On 10 October 1956, a non-flying Atlas arrived at Cape Canaveral in Florida, where it was checked for compatibility with the Cape's existing launch facilities. Test flights of the first "Series A" run of missiles would begin in 1957.^[7]

With development of the Atlas expected to take some time, the Thor Intermediate-range ballistic missile (IRBM), with a range of 2,500 km (1,600 mi), had been authorized in 1955 to be developed and deployed in Europe in just three years. The Douglas-produced Thor, the first missile to use inertial guidance, had its basic configuration and size frozen in January 1956. Engine testing began in March 1956 with the first engine delivered by Rocketdyne in August, by which time the inertial guidance system was finished as well. The same month, warhead data was provided to General Electric, which had been contracted to produce the missile's nose cone. The size of the nose cone was fixed in September. Test launches of the completed missile would take place in 1957.^[6]

The US Army’s Wernher von Braun-led Guided Missile Development Division team, that had recently developed the Redstone, was working on its own IRBM, dubbed Jupiter in April 1956. United States Secretary of Defense Charles Wilson authorized this missile in September 1955, to be jointly developed by the Army and the US Navy. The PGM-19 Jupiter would have the same range as the Thor, and it was planned to be deployed by 1961.^[8]

All of these missiles were ultimately adapted into orbital delivery rockets.^{[9]: 131–137}

Full scale tests of the RD-108 rocket engines that would power the R-7 Semyorka, the Soviet Union's first ICBM, began in January 1956. That same month,^{[10]: 137–138} work began in earnest on "Site 1", the launch pad at Ministry of Defense Scientific-Research and Test Firing Range No.5 (NIIP-5), located in the Kazakh Soviet Socialist Republic (now Kazakhstan) near the Syr-Darya river.^[11]: 308 Completed by the end of May, the platform measured 250 m (820 ft) by 100 m (330 ft) by 45 m (148 ft). An exact duplicate was set up for testing and validation purposes in Leningrad, and a full-scale test version of the R-7 was subjected to wind tests thereon. On 5 October, workers finished the road connecting Site 1 and the living settlement at Site 10, nicknamed Zarya.^{[10]: 136–137}

On 2 February 1956, an R-5M Medium-range ballistic missile (MRBM) was the first rocket to fly carrying a live nuclear warhead.^[12] In May and June 1956, three R-5R missiles—R-5Ms with their nuclear payloads replaced with radio control instrument packages—were the first Soviet missiles to be launched with radio guidance. The ground stations developed to control these missiles served as prototypes for those being built to support R-7 operations. A series of ten launches of another R5 variant, the M-5RD, tested other R-7 components including guidance, stabilization, and propellant feed. All of these launches were successful.^[10]: 138

On 30 January 1956, the Soviet government approved Resolution #149-88, authorizing "Object D". This was a satellite massing 1,000 kg (2,200 lb) to 1,400 kg (3,100 lb), about a fourth of which would be devoted to scientific instruments. This proposal, created in 1955 by engineer Mikhail Tikhonravov, had been endorsed by Soviet leader Nikita Khrushchev upon learning that Object D would outmass the announced American satellite by nearly 1,000 times. Work on the project began in February 1956 with a planned launch date of latter 1957. The design was finalized on 24 July.^[1]: 25

By the 1956, it had become clear that the complicated Object D would not be finished in time for a 1957 launch. Thus, in December 1956, OKB-1 head Sergei Korolev proposed the development of two simpler satellites: PS, Prosteishy Sputnik, or Preliminary Satellite. The two PS satellites would be simple spheres massing 83.4 kg (184 lb) and equipped solely with a radio antenna. The project was approved by the government on 25 January 1957.^[1]: 27

In 1955, Japan developed its first experimental rocket, the 23 cm (9.1 in) long Pencil.^[13] With an eye toward developing a sounding rocket that could meet the 60 km (37 mi) to 100 km (62 mi) minimum altitude requirement for the IGY, the Japanese began development of the Kappa series of rockets, the last of which would fulfill the IGY height limit. Kappa 1, first in this series, 128 mm in diameter and with an initial acceleration of 25 gees,^[14] was launched seven times in 1956.^[15]

Under the aegis of Canada's Defense Research Board, the United States Army built the Churchill Rocket Research Range 24 km (15 mi) east of Churchill, Manitoba. Due to its proximity to the north magnetic pole, it offered an excellent vantage from which to explore auroral activity. Sounding rocket launches began in October 1956, and the facility would become the nation's premier upper atmosphere research center.^[16]

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