Rockets launched the Space Age. They provided the power needed to take spacecraft and people on flights beyond the Earth. Starting with the launch of the first satellite Sputnik in 1957 and continuing through today, countries and companies around the globe have built a variety of rockets to travel into space for science, defense, commerce, and tourism.  

Early rocket technology for spaceflight from the mid-1940s into the 1960s developed alongside—and in many cases because of—military applications for missiles. In the early Cold War, both the United States and the Soviet Union began building rockets to use as long-range weapons. But this race to build missiles for defense soon turned into a race to build rockets for space exploration. The same rocket that could carry a nuclear warhead could (and sometimes did) also launch spacecraft into orbit. This intense investment in engineering for missiles and rockets sparked off the Space Race.  

The Race to Recreate and Improve the V-2

The V-2 (Vengeance Weapon 2, Vergeltungswaffe 2), also known by its technical name A-4 (Aggregat 4), was the first guided long-range ballistic missile. Forced and enslaved laborers from various Nazi concentration camp systems built the V-2. While the missile had relatively little effect on the war effort, the V-2 became important for the history of rocketry because both the United States and the Soviet Union used captured V-2s as a basis for developing their own large rockets and missiles.  

The American Effort 

At the time that Germany was launching V-2 missiles against war-torn Europe, long-range missiles were still in the planning stages in the United States. The WAC Corporal rocket represented the state of U.S. rocketry at the war’s close in 1945. It was a small liquid-propellant rocket developed by the Jet Propulsion Laboratory for the U.S. Army. It used an attached solid-propellant booster to clear the launch tower. The first WAC was launched at White Sands Proving Ground, New Mexico in October 1945. It reached an altitude of about 45 miles (75 kilometers). Improved versions of the rocket reached 60 miles (100 kilometers). The WAC Corporal was a sounding rocket, meaning that it conducted scientific research during its short suborbital flights. 

At the end of the war, the United States carried out a secret intelligence plan known as Operation Paperclip, which brought more than 1,600 scientists, engineers, and technicians from Germany for employment in the U.S. government. Along with other scientific and engineering applications, Operation Paperclip provided the United States with access to the V-2 program. The U.S. gained captured V-2 missiles and access to many of the engineers who had designed them. V-2 engineers such as Wernher von Braun advised the technicians from General Electric who were charged with identifying and reassembling V-2 components in White Sands, New Mexico. 

The Viking represented the U.S. Navy’s refinement of the V-2 into a more powerful rocket. The U.S. Navy began work on a sounding rocket to meet its research needs and to gain experience in designing and building large missiles in 1946. From 1949 through 1957, 14 Vikings were built and flown to test different features and carry larger instrument payloads. Viking's design introduced important innovations in control, structures, and propulsion. No two Vikings were identical. 

The Viking rocket was used mainly to study the region of the upper atmosphere that affects long-range radio communication. The Naval Research Laboratory also conducted a study and test launch to investigate Viking's potential as a tactical ballistic missile.

It was the Army's Corporal missile, however, that became the first U.S. ballistic missile to approach the capability of the German V-2. The Corporal went into production in the early 1950s and was deployed by the U.S. Army in Europe until the mid-1960s. Concurrently, the WAC Corporal was repurposed into the Bumper WAC, a two-stage sounding rocket with a V-2 comprising the first stage and the WAC rocket comprising the second. This combination created the first two-stage liquid-propellant rocket. 

The The Navy made a larger version of the Army’s WAC Corporal rocket known as the Aerobee. The Aerobee was first produced for the Applied Physics Laboratory at Johns Hopkins University. Improvements led to a family of Aerobee sounding rockets for both military and civilian use. More than 1,000 Aerobees were launched from 1947 to 1985. 

The Soviet Effort 

The Soviet Union took the V-2 rockets they captured at the end of the war and used them to develop their own large-scale missile technology. In 1947 the Soviet Union launched its first V-2 assembled from German parts. A year later, the country launched the first domestically produced V-2. This Soviet version was called the R-1 missile.  

The Soviets went on to develop a variety of sounding rockets and missiles based on the V-2. They gradually increased engine thrust, made the body larger, and integrated propellant tanks with the missile's skin. These technical refinements increased the missile's range. The R-5, the last Soviet missile based on V-2 technology, had a range of 750 miles (1,200 kilometers). 

The ICBM Launches the Space Race 

Technological improvements gradually led to the creation of the intercontinental ballistic missile (ICBM). Traveling at least five times faster than sound (hypersonic speed) and independent of signals from the ground, the ICBM seemed to be the "ultimate weapon."  

From 1954 to 1957, Soviet rocket designer Sergei Korolëv headed development of the R-7, the world's first ICBM. Successfully flight tested in August 1957, the R-7 missile was powerful enough to launch a nuclear warhead against the United States and also powerful enough to launch a spacecraft into orbit. 

Meanwhile, the U.S. was also giving more consideration to long-range ballistic missiles. Opinion especially changed in response to developments in atomic capabilities. By 1953 U.S. weapons designers had already invented a way to make hydrogen bombs small and lightweight. This meant that an ICBM did not need to be as large as previously thought. The "Bravo" test, conducted in the South Pacific in 1954, confirmed the feasibility of the new smaller H-bomb design. A top-secret report presented to the U.S. Air Force in early 1954 assessed ballistic missiles in light of these recent advances in nuclear weapons technology. The Strategic Missiles Evaluation Committee worried that the Soviet Union might be ahead of the United States in long-range ballistic missiles and recommended that the Air Force treat missile development as "an extremely high priority." The era of the ICBM was at hand. 

The United States and the Soviet Union announced individual intentions to place a scientific satellite into orbit as part of the 1957-1958 International Geophysical Year, a worldwide effort to study the Earth. The Army proposed to launch America's first satellite using a modified Redstone ballistic missile. Instead, Vanguard—a new vehicle descended from research rockets—was selected for technical reasons and to emphasize the peaceful use of space. 

However, 

on October 4, 1957, a Soviet ICBM launched the satellite Sputnik and the Space Age. This event startled the world, giving the impression that America was behind the Soviets in science and technology. Subsequent U.S. launch failures heightened that perception. What began as a competition to build new rockets for defense and militaristic purposes now also became a competition to reach space. 

After Sputnik's success, the explosion of Vanguard on its launch pad on December 6, 1957 drew further attention to the Soviet lead in space. America's first success in space came on January 31, 1958, when Explorer 1 was launched aboard an Army Jupiter-C, which was a modified Redstone ballistic missile. In February a second U.S. attempt to launch a Vanguard satellite failed. The American media and Congress demanded to know how the Soviets had beaten the United States into space. One response by the Eisenhower administration and Congress was to establish the National Aeronautics and Space Administration (NASA).