Space Race

The Space Race was a 20th-century competition between two Cold War rivals, the Soviet Union (USSR) and the United States (US), for supremacy in spaceflight capability. It had its origins in the missile-based nuclear arms race between the two nations that occurred following World War II, enabled by captured German rocket technology and personnel. The technological superiority required for such supremacy was seen as necessary for national security, and symbolic of ideological superiority. The Space Race spawned pioneering efforts to launch artificial satellites, unmanned space probes of the Moon, Venus, and Mars, and human spaceflight in low Earth orbit and to the Moon.

The competition began on August 2, 1955, when the Soviet Union responded to the US announcement four days earlier of intent to launch artificial satellites for the International Geophysical Year, by declaring they would also launch a satellite "in the near future". The Soviet Union beat the US to this, with the October 4, 1957 orbiting of Sputnik 1, and later beat the US to the first human in space, Yuri Gagarin, on April 12, 1961. The race peaked with the July 20, 1969 US landing of the first humans on the Moon with Apollo 11. The USSR tried but failed manned lunar missions, and eventually cancelled them and concentrated on Earth orbital space stations.

A period of détente followed with the April 1972 agreement on a co-operative Apollo–Soyuz Test Project, resulting in the July 1975 rendezvous in Earth orbit of a US astronaut crew with a Soviet cosmonaut crew. The end of the Space Race is harder to pinpoint than its beginning, but it was over by the December, 1991 dissolution of the Soviet Union, after which true spaceflight cooperation between the US and Russia began.

The Space Race has left a legacy of Earth communications and weather satellites, and continuing human space presence on the International Space Station. It has also sparked increases in spending on education and research and development, which led to beneficial spin-off technologies.

World War II Germany
The Space Race can trace its origins to Germany, beginning in the 1930s and continuing during World War II when Nazi Germany researched and built operational ballistic missiles. Starting in the early 1930s, during the last stages of the Weimar Republic, German aerospace engineers experimented with liquid-fueled rockets, with the goal that one day they would be capable of reaching high altitudes and traversing long distances. The head of the German Army's Ballistics and Munitions Branch, Lieutenant Colonel Karl Emil Becker, gathered a small team of engineers that included Walter Dornberger and Leo Zanssen, to figure out how to use rockets as long-range artillery in order to get around the Treaty of Versailles' ban on research and development of long-range cannons. Wernher von Braun, a young engineering prodigy, was recruited by Becker and Dornberger to join their secret army program at Kummersdorf-West in 1932. Von Braun had dreams about conquering outer space with rockets, and did not initially see the military value in missile technology.

During the Second World War, General Dornberger was the military head of the army's rocket program, Zanssen became the commandant of the Peenemünde army rocket center, and von Braun was the technical director of the ballistic missile program. They led the team that built the Aggregate-4 (A-4) rocket, which became the first vehicle to reach outer space during its test flight program in 1942 and 1943. By 1943, Germany began mass-producing the A-4 as the Vergeltungswaffe 2 ("Vengeance Weapon" 2, or more commonly, V2), a ballistic missile with a 320 km range carrying a 1130 kg warhead at 4000 km/h. Its supersonic speed meant there was no defense against it, and radar detection provided little warning. Germany used the weapon to bombard southern England and parts of Allied-liberated western Europe from 1944 until 1945. After the war, the V-2 became the basis of early American and Soviet rocket designs.

At war's end, American, British, and Soviet scientific intelligence teams competed to capture Germany's rocket engineers along with the German rockets themselves and the designs on which they were based. Each of the Allies captured a share of the available members of the German rocket team, but the United States benefited the most with Operation Paperclip, recruiting von Braun and most of his engineering team, who later helped develop the American missile and space exploration programs. The United States also acquired a large number of complete V2 rockets.

Soviet rocket development
The German rocket center in Peenemünde was located in the eastern part of Germany, which became the Soviet zone of occupation. On Stalin's orders, the Soviet Union sent its best rocket engineers to this region to see what they could salvage for future weapons systems. The Soviet rocket engineers were led by Sergei Korolev. He had been involved in space clubs and early Soviet rocket design in the 1930s, but was arrested in 1938 during Joseph Stalin's Great Purge and imprisoned for six years in Gulag. After the war, he became the USSR's chief rocket and spacecraft engineer, essentially the Soviet counterpart to von Braun. His identity was kept a state secret throughout the Cold War, and he was identified publicly only as "the Chief Designer." In the West, his name was only officially revealed when he died in 1966.

After almost a year in the area around Peenemünde, Soviet officials moved most of the captured German rocket specialists to Gorodomlya Island on Lake Seliger, about 240 km northwest of Moscow. They were not allowed to participate in Soviet missile design, but were used as problem-solving consultants to the Soviet engineers. They helped in the following areas: the creation of a Soviet version of the A-4; work on "organizational schemes"; research in improving the A-4 main engine; development of a 100-ton engine; assistance in the "layout" of plant production rooms; and preparation of rocket assembly using German components. With their help, particularly Helmut Groettrup's group, Korolev reverse-engineered the A-4 and built his own version of the rocket, the R-1, in 1948. Later, he developed his own distinct designs, though many of these designs were influenced by the Groettrup Group's G4-R10 design from 1949. The Germans were eventually repatriated in 1951–53.

American rocket development
The American professor Robert H. Goddard had worked on developing solid-fuel rockets since 1914, and demonstrated a light battlefield rocket to the US Army Signal Corps only five days before the signing of the armistice that ended World War I. He also started developing liquid-fueled rockets in 1921; yet he had not been taken seriously by the public.

Von Braun and his team were sent to the United States Army's White Sands Proving Ground, located in New Mexico, in 1945. They set about assembling the captured V2s and began a program of launching them and instructing American engineers in their operation. These tests led to the first rocket to take photos from outer space, and the first two-stage rocket, the WAC Corporal-V2 combination, in 1949. The German rocket team was moved from Fort Bliss to the Army's new Redstone Arsenal, located in Huntsville, Alabama, in 1950. From here, von Braun and his team developed the Army's first operational medium-range ballistic missile, the Redstone rocket, that in slightly modified versions, launched both America's first satellite, and the first piloted Mercury space missions. It became the basis for both the Jupiter and Saturn family of rockets.

Cold War missile race
The Cold War (1947–1991) developed between two former allies, the Soviet Union and the United States, soon after the end of the Second World War. It involved a continuing state of political conflict, military tension, proxy wars, and economic competition, primarily between the Soviet Union and its satellite states (often referred to as the Eastern Bloc), and the powers of the Western world, particularly the United States. The primary participants' military forces never clashed directly, but expressed this conflict through military coalitions, strategic conventional force deployments, extensive aid to states deemed vulnerable, proxy wars, espionage, propaganda, a nuclear arms race, and economic and technological competitions, such as the Space Race.

In simple terms, the Cold War could be viewed as an expression of the ideological struggle between communism and capitalism. The United States faced a new uncertainty beginning in September 1949, when it lost its monopoly on the atomic bomb. American intelligence agencies discovered that the Soviet Union had exploded its first atomic bomb, with the consequence that the United States potentially could face a future nuclear war that, for the first time, might devastate its cities. Given this new danger, the United States participated in an arms race with the Soviet Union that included development of the hydrogen bomb, as well as intercontinental strategic bombers and intercontinental ballistic missiles (ICBMs) capable of delivering nuclear weapons. A new fear of communism and its sympathizers swept the United States during the 1950s, which devolved into paranoid McCarthyism. With communism spreading in China, Korea, and Eastern Europe, Americans came to feel so threatened that popular and political culture condoned extensive "witch-hunts" to expose communist spies. Part of the American reaction to the Soviet atomic and hydrogen bomb tests included maintaining a large Air Force, under the control of the Strategic Air Command (SAC). SAC employed intercontinental strategic bombers, as well as medium-bombers based close to Soviet airspace (in western Europe and in Turkey) that were capable of delivering nuclear payloads.

For its part, the Soviet Union harbored fears of invasion. Having suffered at least 27 million casualties during World War II after being invaded by Nazi Germany in 1941, the Soviet Union was wary of its former ally, the United States, which until late 1949 was the sole possessor of atomic weapons. The United States had used these weapons operationally during World War II, and it could use them again against the Soviet Union, laying waste its cities and military centers. Since the Americans had a much larger air force than the Soviet Union, and the United States maintained advance air bases near Soviet territory, in 1947 Stalin ordered the development of intercontinental ballistic missiles (ICBMs) in order to counter the perceived American threat.

In 1953, Korolev was given the go-ahead to develop the R-7 Semyorka rocket, which represented a major advance from the German design. Although some of its components (notably boosters) still resembled the German G-4, the new rocket incorporated staged design, a completely new control system, and a new fuel. It was successfully tested on August 21, 1957 and became the world's first fully operational ICBM the following month. It was later used to launch the first satellite into space, and derivatives launched all piloted Soviet spacecraft.

The United States had multiple rocket programs divided among the different branches of the American armed services, which meant that each force developed its own ICBM program. The Air Force initiated ICBM research in 1945 with the MX-774. However, its funding was cancelled and only three partially successful launches were conducted in 1947. In 1950, von Braun began testing the Air Force PGM-11 Redstone rocket family at Cape Canaveral. In 1951, the Air Force began a new ICBM program called MX-1593, and by 1955 this program was receiving top-priority funding. The MX-1593 program evolved to become the Atlas-A, with its maiden launch occurring June 11, 1957, becoming the first successful American ICBM. Its upgraded version, the Atlas-D rocket, later served as a nuclear ICBM and as the orbital launch vehicle for Project Mercury and the remote-controlled Agena Target Vehicle used in Project Gemini.

With the Cold War as an engine for change in the ideological competition between the United States and the Soviet Union, a coherent space policy began to take shape in the United States during the late 1950s. Korolev took inspiration from the competition as well, achieving many firsts to counter the possibility that the United States might prevail.

First artificial satellite
In 1955, with both the United States and the Soviet Union building ballistic missiles that could be utilized to launch objects into space, the "starting line" was drawn for the Space Race. In separate announcements four days apart, both nations publicly announced that they would launch artificial Earth satellites by 1957 or 1958. On July 29, 1955, James C. Hagerty, president Dwight D. Eisenhower's press secretary, announced that the United States intended to launch "small Earth circling satellites" between July 1, 1957, and December 31, 1958, as part of their contribution to the International Geophysical Year (IGY). Four days later, at the Sixth Congress of International Astronautical Federation in Copenhagen, scientist Leonid I. Sedov spoke to international reporters at the Soviet embassy, and announced his country's intention to launch a satellite as well, in the "near future". On August 30, 1955, Korolev managed to get the Soviet Academy of Sciences to create a commission whose purpose was to beat the Americans into Earth orbit: this was the de facto start date for the Space Race. The Council of Ministers of the Soviet Union began a policy of treating development of its space program as a classified state secret.

Initially, President Eisenhower was worried that a satellite passing above a nation at over 100 km, might be construed as violating that nation's sovereign airspace. He was concerned that the Soviet Union would accuse the Americans of an illegal overflight, thereby scoring a propaganda victory at his expense. Eisenhower and his advisors believed that a nation's airspace sovereignty did not extend into outer space, acknowledged as the Kármán line, and he used the 1957–58 International Geophysical Year launches to establish this principle in international law. Eisenhower also feared that he might cause an international incident and be called a "warmonger" if he were to use military missiles as launchers. Therefore, he selected the untried Naval Research Laboratory's Vanguard rocket, which was a research-only booster. This meant that von Braun's team was not allowed to put a satellite into orbit with their Jupiter-C rocket, because of its intended use as a future military vehicle. On September 20, 1956, von Braun and his team did launch a Jupiter-C that was capable of putting a satellite into orbit, but the launch was used only as a suborbital test of nose cone reentry technology.

Korolev received word about von Braun's 1956 Jupiter-C test, but thinking it was a satellite mission that failed, he expedited plans to get his own satellite in orbit. Since his R-7 was substantially more powerful than any of the American boosters, he made sure to take full advantage of this capability by designing Object D as his primary satellite. It was given the designation 'D', to distinguish it from other R-7 payload designations 'A', 'B', 'V', and 'G' which were nuclear weapon payloads. Object D dwarfed the proposed American satellites, by having a weight of 1400 kg, of which 300 kg would be composed of scientific instruments that would photograph the Earth, take readings on radiation levels, and check on the planet's magnetic field. However, things were not going along well with the design and manufacturing of the satellite, so in February 1957, Korolev sought and received permission from the Council of Ministers to create a prosteishy sputnik (PS-1), or simple satellite. The Council also decreed that Object D be postponed until April 1958. The new sputnik was a shiny sphere that would be a much lighter craft, weighing 83.8 kg and having a 58 cm diameter. The satellite would not contain the complex instrumentation that Object D had, but had two radio transmitters operating on different short wave radio frequencies, the ability to detect if a meteoroid were to penetrate its pressure hull, and the ability to detect the density of the Earth's thermosphere.

Korolev was buoyed by the first successful launches of his R-7 rocket in August and September, which paved the way for him to launch his sputnik. Word came that the Americans were planning to announce a major breakthrough at an International Geophysical Year conference at the National Academy of Sciences in Washington D.C., with a paper entitled "Satellite Over the Planet", on October 6, 1957. Korolev anticipated that von Braun might launch a Jupiter-C with a satellite payload on or around October 4 or 5, in conjunction with the paper. He hastened the launch, moving it to October 4. The launch vehicle for PS-1, was a modified R-7 – vehicle 8K71PS number M1-PS– without much of the test equipment and radio gear that was present in the previous launches. It arrived at the Soviet missile base Tyura-Tam in September and was prepared for its mission at launch site number one. On Friday, October 4, 1957, at exactly 10:28:34 pm Moscow time, the R-7, with the now named Sputnik 1 satellite, lifted off the launch pad, and placed this artificial "moon" into an orbit a few minutes later. This "fellow traveler," as the name is translated in English, was a small, beeping ball, less than two feet in diameter and weighing less than 200 pounds. But the celebrations were muted at the launch control center until the down-range far east tracking station at Kamchatka received the first distinctive beep ... beep ... beep sounds from Sputnik 1's radio transmitters, indicating that it was on its way to completing its first orbit. About 95 minutes after launch, the satellite flew over its launch site, and its radio signals were picked up by the engineers and military personnel at Tyura-Tam: that's when Korolev and his team celebrated the first successful artificial satellite placed into Earth-orbit.

US reaction
The Soviet success raised a great deal of concern in the United States. For example, economist Bernard Baruch wrote in an open letter titled “The Lessons of Defeat" to the New York Herald Tribune: "While we devote our industrial and technological power to producing new model automobiles and more gadgets, the Soviet Union is conquering space. ... It is Russia, not the United States, who has had the imagination to hitch its wagon to the stars and the skill to reach for the moon and all but grasp it. America is worried. It should be."

Eisenhower ordered project Vanguard to move up its timetable and launch its satellite much sooner than originally planned. The December 6, 1957 Project Vanguard launch failure occurred at Cape Canaveral Air Force Station in Florida, broadcast live in front of a US television audience. It was a monumental failure, exploding a few seconds after launch, and it became an international joke. The satellite appeared in newspapers under the names Flopnik, Stayputnik, Kaputnik, and Dudnik. In the United Nations, the Russian delegate offered the U.S. representative aid "under the Soviet program of technical assistance to backwards nations." Only in the wake of this very public failure did von Braun's Redstone team get the go-ahead to launch their Jupiter-C rocket as soon as they could. In Britain, the US's Western Cold War ally, the reaction was mixed: some celebrated the fact that the Soviets had reached space first, while others feared the destructive potential that military uses of spacecraft might bring.

On January 31, 1958, nearly four months after the launch of Sputnik 1, von Braun and the United States successfully launched its first satellite on a four-stage Juno I rocket derived from the US Army's Redstone missile, at Cape Canaveral. The satellite Explorer 1 was 30.8 lb in mass. It carried a micrometeorite gauge and a Geiger-Müller tube. It passed in and out of the Earth-encompassing radiation belt with its 360 by orbit, therefore saturating the tube's capacity and proving what Dr. James Van Allen, a space scientist at the University of Iowa, had theorized. The belt, named the Van Allen radiation belt, is a doughnut-shaped zone of high-level radiation intensity around the Earth above the magnetic equator. Van Allen was also the man who designed and built the satellite instrumentation of Explorer 1. The satellite measured three phenomena: cosmic ray and radiation levels, the temperature in the spacecraft, and the frequency of collisions with micrometeorites. The satellite had no memory for data storage, therefore it had to transmit continuously. In March 1958 a second satellite was sent into orbit with augmented cosmic ray instruments.

On April 2, 1958, President Eisenhower reacted to the Soviet space lead in launching the first satellite, by recommending to the US Congress that a civilian agency be established to direct nonmilitary space activities. Congress, led by Senate Majority Leader Lyndon B. Johnson, responded by passing the National Aeronautics and Space Act, which Eisenhower signed into law on July 29, 1958. This law turned the National Advisory Committee on Aeronautics into the National Aeronautics and Space Administration (NASA). It also created a Civilian-Military Liaison Committee, chaired by the President, responsible for coordinating the nation's civilian and military space programs.

On October 21, 1959, Eisenhower approved the transfer of the Army's remaining space-related activities to NASA. On July 1, 1960, the Redstone Arsenal became NASA's George C. Marshall Space Flight Center, with von Braun as its first director. Development of the Saturn rocket family, which when mature, gave the US parity with the Soviets in terms of lifting capability, was thus transferred to NASA.

Unmanned lunar probes
In 1958, Korolev upgraded the R-7 to be able to launch a 400 kg payload to the Moon. Three secret 1958 attempts to launch Luna E-1-class impactor probes failed. The fourth attempt, Luna 1, launched successfully on January 2, 1959, but missed the Moon. The fifth attempt on June 18 also failed at launch. The 390 kg Luna 2 successfully impacted the Moon on September 14, 1959. The 278.5 kg Luna 3 successfully flew by the Moon and sent back pictures of its far side on October 6, 1959.

The US reacted to the Luna program by embarking on the Ranger program in 1959, managed by NASA's Jet Propulsion Laboratory. The Block I Ranger 1 and Ranger 2 suffered Atlas-Agena launch failures in August and November 1961. The 727 lb Block II Ranger 3 launched successfully on January 26, 1962, but missed the Moon. The 730 lb Ranger 4 became the first US spacecraft to reach the Moon, but its solar panels and navigational system failed near the Moon and it impacted the far side without returning any scientific data. Ranger 5 ran out of power and missed the Moon by 725 km on October 21, 1962. The first successful Ranger mission was the 806 lb Block III Ranger 7 which impacted on July 31, 1964.

First human in space
By 1959, American observers believed that the Soviet Union would be the first to get a human into space, because of the time needed to prepare for Mercury's first launch. On April 12, 1961, the USSR surprised the world again by launching Yuri Gagarin into a single orbit around the Earth in a craft they called Vostok 1. They dubbed Gagarin the first cosmonaut, roughly translated from Russian and Greek as "sailor of the universe". Although he had the ability to take over manual control of his capsule in an emergency by opening an envelope he had in the cabin that contained a code that could be typed into the computer, it was flown in an automatic mode as a precaution; medical science at that time did not know what would happen to a human in the weightlessness of space. Vostok 1 orbited the Earth for 108 minutes and made its reentry over the Soviet Union, with Gagarin ejecting from the spacecraft at 7000 m, and landing by parachute. The Fédération Aéronautique Internationale (International Federation of Aeronautics) credited Gagarin with the world's first human space flight, although their qualifying rules for aeronautical records at the time required pilots to take off and land with their craft. For this reason, the Soviet Union omitted from their FAI submission the fact that Gagarin did not land with his capsule. When the FAI filing for Gherman Titov's second Vostok flight in August 1961 disclosed the ejection landing technique, the FAI committee decided to investigate, and concluded that the technological accomplishment of human spaceflight lay in the safe launch, orbiting, and return, rather than the manner of landing, and revised their rules, keeping Gagarin's and Titov's records intact.

Gagarin became a national hero of the Soviet Union and the Eastern Bloc, and a worldwide celebrity. Moscow and other cities in the USSR held mass demonstrations, the scale of which was second only to the World War II Victory Parade of 1945. April 12 was declared Cosmonautics Day in the USSR, and is celebrated today in Russia as one of the official "Commemorative Dates of Russia." In 2011, it was declared the International Day of Human Space Flight by the United Nations.

The radio communication between the launch control room and Gagarin included the following dialogue at the moment of rocket launch:

"Korolev: "Preliminary stage..... intermediate..... main..... lift off! We wish you a good flight. Everything is all right."

Gagarin: "Поехали!" (Poyekhali! - Let's go!)." Gagarin's informal poyekhali! became a historical phrase in the Eastern Block, used to refer to the beginning of the human space flight era.

First American in space
The US Air Force had been developing a program to launch the first man in space, named Man in Space Soonest. This program studied several different types of one-man space vehicles, settling on a ballistic re-entry capsule launched on a derivative Atlas missile, and selecting a group of nine candidate pilots. After NASA's creation, the program was transferred over to the civilian agency and renamed Project Mercury on November 26, 1958. NASA selected a new group of astronaut (from the Greek for "star sailor") candidates from Navy, Air Force and Marine test pilots, and narrowed this down to a group of seven for the program. Capsule design and astronaut training began immediately, working toward preliminary suborbital flights on the Redstone missile, followed by orbital flights on the Atlas. Each flight series would first start unmanned, then carry a non-human primate, then finally men.

Three weeks later, on May 5, 1961, Alan Shepard became the first American in space, launched in a ballistic trajectory on Mercury-Redstone 3, in a spacecraft he named Freedom 7. Though he did not achieve orbit like Gagarin, he was the first person to exercise manual control over his spacecraft's attitude and retro-rocket firing. After his successful return, Shepard was celebrated as a national hero, honored with parades in Washington, New York and Los Angeles, and received the NASA Distinguished Service Medal from President John F. Kennedy.

Kennedy directs the race toward the Moon
Before Gagarin's flight, US President John F. Kennedy's support for America's manned space program was lukewarm. Jerome Wiesner of MIT, who served as a science advisor to presidents Eisenhower and Kennedy, and himself an opponent of manned space exploration, remarked, "If Kennedy could have opted out of a big space program without hurting the country in his judgement, he would have." As late as March 1961, when NASA administrator James E. Webb submitted a budget request to fund a Moon landing before 1970, Kennedy rejected it because it was simply too expensive. Some were surprised by Kennedy's eventual support of NASA and the space program because of how often he had attacked the Eisenhower administration's inefficiency during the election.

Gagarin's flight changed this; now Kennedy sensed the humiliation and fear on the part of the American public over the Soviet lead. Additionally, the Bay of Pigs invasion, planned before his term began but executed during it, was an embarrassment to his administration due to the colossal failure of the American forces. Looking for something to save political face, he sent a memo dated April 20, 1961, to Vice President Lyndon B. Johnson, asking him to look into the state of America's space program, and into programs that could offer NASA the opportunity to catch up. The two major options at the time seemed to be, either establishment of an Earth orbital space station, or a manned landing on the Moon. Johnson in turn consulted with von Braun, who answered Kennedy's questions based on his estimates of US and Soviet rocket lifting capability. Based on this, Johnson responded to Kennedy, concluding that much more was needed to reach a position of leadership, and recommending that the manned Moon landing was far enough in the future that the US had a fighting chance to achieve it first.

Kennedy ultimately decided to pursue what became the Apollo program, and on May 25 took the opportunity to ask for Congressional support in a Cold War speech titled "Special Message on Urgent National Needs".

He justified the program in terms of its importance to national security, and its focus of the nation's energies on other scientific and social fields. He rallied popular support for the program in his "We choose to go to the Moon" speech, on September 12, 1962, before a large crowd at Rice University Stadium, in Houston, Texas, near the construction site of the new Manned Spacecraft Center facility.

Khrushchev responded to Kennedy's implicit challenge with silence, refusing to publicly confirm or deny the Soviets were pursuing a "Moon race". As later disclosed, they pursued such a program in secret over the next nine years.

Mercury
American Virgil "Gus" Grissom repeated Shepard's suborbital flight in Liberty Bell 7 on July 21, 1961. Almost a year after the Soviet Union put a human into orbit, astronaut John Glenn became the first American to orbit the Earth, on February 20, 1962. His Mercury-Atlas 6 mission completed three orbits in the Friendship 7 spacecraft, and splashed down safely in the Atlantic Ocean, after a tense reentry, due to what falsely appeared from the telemetry data to be a loose heat-shield. As the first American in orbit, Glenn became a national hero, and received a ticker-tape parade in New York City, reminiscent of that given for Charles Lindbergh. On February 23, 1962, President Kennedy escorted him in a parade at Cape Canaveral Air Force Station, where he awarded Glenn with the NASA service medal.

The United States launched three more Mercury flights after Glenn's: Aurora 7 on May 24, 1962 duplicated Glenn's three orbits; Sigma 7 on October 3, 1962, six orbits; and Faith 7 on May 15, 1963, 22 orbits (32.4 hours), the maximum capability of the spacecraft. NASA at first intended to launch one more mission, extending the spacecraft's endurance to three days, but since this would not beat the Soviet record, it was decided instead to concentrate on developing Project Gemini.

Vostok
Gherman Titov became the first Soviet cosmonaut to exercise manual control of his Vostok 2 craft on August 6, 1961. The Soviet Union demonstrated 24-hour launch pad turnaround and the capability to launch two piloted spacecraft, Vostok 3 and Vostok 4, in essentially identical orbits, on August 11 and 12, 1962. The two spacecraft came within approximately 6.5 km of one another, close enough for radio communication. Vostok 4 also set a record of nearly four days in space. Though the two craft's orbits were as nearly identical as possible given the accuracy of the launch rocket's guidance system, slight variations still existed which drew the two craft at first as close to each other as 6.5 km, then as far apart as 2850 km. There were no maneuvering rockets on the Vostok to permit space rendezvous, required to keep two spacecraft a controlled distance apart. The Soviet Union duplicated its dual-launch feat with Vostok 5 and Vostok 6 (June 16, 1963). This time they launched the first woman (also the first civilian), Valentina Tereshkova, into space on Vostok 6. Launching a woman was reportedly Korolev's idea, and it was accomplished purely for propaganda value. Tereshkova was one of a small corps of female cosmonauts who were amateur parachutists, but Tereshkova was the only one to fly. The USSR didn't again open its cosmonaut corps to women until 1980, two years after the United States opened its astronaut corps to women.

The Soviets kept the details and true appearance of the Vostok capsule secret until the April 1965 Moscow Economic Exhibition, where it was first displayed without its aerodynamic nose cone concealing the spherical capsule. The "Vostok spaceship" had been first displayed at the July 1961 Tushino air show, mounted on its launch vehicle's third stage, with the nose cone in place. A tail section with eight fins was also added, in an apparent attempt to confuse western observers. This spurious tail section also appeared on official commemorative stamps and a documentary.

Kennedy proposes a joint US-USSR program
On September 20, 1963, in a speech before the United Nations General Assembly, President Kennedy proposed that the United States and the Soviet Union join forces in their efforts to reach the Moon. Soviet Premier Nikita Khrushchev initially rejected Kennedy's proposal.

On October 2, 1997, it was reported that Khrushchev's son Sergei claimed Khrushchev was poised to accept Kennedy's proposal at the time of Kennedy's assassination on November 22, 1963. During the next few weeks he reportedly concluded that both nations might realize cost benefits and technological gains from a joint venture, and decided to accept Kennedy's offer based on a measure of rapport during their years as leaders of the world's two superpowers, but changed his mind and dropped the idea since he did not have the same trust for Kennedy's successor, Lyndon Johnson.

As President, Johnson steadfastly pursued the Gemini and Apollo programs, promoting them as Kennedy's legacy to the American public. One week after Kennedy's death, he issued an executive order renaming the Cape Canaveral and Apollo launch facilities after Kennedy.

Gemini and Voskhod
Focused by the commitment to a Moon landing, in January 1962 the US announced Project Gemini, a two-man spacecraft that would support the later three-man Apollo by developing the key spaceflight technologies of space rendezvous and docking of two craft, flight durations of sufficient length to simulate going to the Moon and back, and extra-vehicular activity to accomplish useful work outside the spacecraft.

Meanwhile, Korolev had planned further, long-term missions for the Vostok spacecraft, and had four Vostoks in various stages of fabrication in late 1963 at his OKB-1 facilities. At that time, the Americans announced their ambitious plans for the Project Gemini flight schedule. These plans included major advancements in spacecraft capabilities, including a two-person spacecraft, the ability to change orbits, the capacity to perform an extravehicular activity (EVA), and the goal of docking with another spacecraft. These represented major advances over the previous Mercury or Vostok capsules, and Korolev felt the need to try to beat the Americans to many of these innovations. Korolev already had begun designing the Vostok's replacement, the next-generation Soyuz spacecraft, a multi-cosmonaut spacecraft that had at least the same capabilities as the Gemini spacecraft. Soyuz would not be available for at least three years, and it could not be called upon to deal with this new American challenge in 1964 or 1965. Political pressure in early 1964–which some sources claim was from Khrushchev while other sources claim was from other Communist Party officials—pushed him to modify his four remaining Vostoks to beat the Americans to new space firsts in the size of flight crews, and the duration of missions.

Voskhod program
The greater advances of the Soviet space program at the time allowed their space program to achieve other significant firsts, including the first EVA "spacewalk" and the first mission performed by a crew in shirt-sleeves. Gemini took a year longer than planned to accomplish its first flight, allowing the Soviets to achieve another first, launching Voskhod 1 on October 12, 1964, the first spacecraft with a three-cosmonaut crew. The USSR touted another technological achievement during this mission: it was the first space flight during which cosmonauts performed in a shirt-sleeve-environment. However, flying without spacesuits was not due to safety improvements in the Soviet spacecraft's environmental systems; rather this innovation was accomplished because the craft's limited cabin space did not allow for spacesuits. Flying without spacesuits exposed the cosmonauts to significant risk in the event of potentially fatal cabin depressurization. This feat was not repeated until the US Apollo Command Module flew in 1968; this later mission was designed from the outset to safely transport three astronauts in a shirt-sleeve environment while in space.

Between October 14–16, 1964, Leonid Brezhnev and a small cadre of high-ranking Communist Party officials, deposed Khrushchev as Soviet government leader a day after Voskhod 1 landed, in what was called the "Wednesday conspiracy". The new political leaders, along with Korolev, ended the technologically troublesome Voskhod program, cancelling Voskhod 3 and 4, which were in the planning stages, and started concentrating on the race to the Moon. Voskhod 2 ended up being Korolev's final achievement before his death on January 14, 1966, as it became the last of the many space firsts that demonstrated the USSR's domination in spacecraft technology during the early 1960s. According to historian Asif Siddiqi, Korolev's accomplishments marked "the absolute zenith of the Soviet space program, one never, ever attained since." There was a two-year pause in Soviet piloted space flights while Voskhod's replacement, the Soyuz spacecraft, was designed and developed.

On March 18, 1965, about a week before the first American piloted Project Gemini space flight, the USSR accelerated the competition, by launching the two-cosmonaut Voskhod 2 mission with Pavel Belyayev and Alexey Leonov. Voskhod 2's design modifications included the addition of an inflatable airlock to allow for extravehicular activity (EVA), also known as a spacewalk, while keeping the cabin pressurized so that the capsule's electronics would not overheat. Leonov performed the first-ever EVA as part of the mission. A fatality was narrowly avoided when Leonov's spacesuit expanded in the vacuum of space, preventing him from re-entering the airlock. In order to overcome this, he had to partially depressurize his spacesuit to a potentially dangerous level. He succeeded in safely re-entering the ship, but he and Belyayev faced further challenges when the spacecraft's atmospheric controls flooded the cabin with 45% pure oxygen, which had to be lowered to acceptable levels before re-entry. The reentry involved two more challenges: an improperly timed retrorocket firing caused the Voskhod 2 to land 386 km off its designated target area, the town of Perm; and the instrument compartment's failure to detach from the descent apparatus caused the spacecraft to become unstable during reentry.



Project Gemini
Though delayed a year to reach its first flight, Gemini was able to take advantage of the USSR's two-year hiatus after Voskhod, which enabled the US to catch up and surpass the previous Soviet lead in piloted spaceflight. Gemini achieved several significant firsts during the course of ten piloted missions:
 * On Gemini 3 (March 1965), astronauts Virgil "Gus" Grissom and John W. Young became the first to demonstrate their ability to change their craft's orbit.
 * On Gemini 5 (August 1965), astronauts L. Gordon Cooper and Charles "Pete" Conrad set a record of almost eight days in space, long enough for a piloted lunar mission.
 * On Gemini 6A (December 1965), Command Pilot Wally Schirra achieved the first space rendezvous with Gemini 7, accurately matching his orbit to that of the other craft, station-keeping for three consecutive orbits at distances as close as 1 ft.
 * Gemini 7 also set a human spaceflight endurance record of fourteen days for Frank Borman and James A. Lovell, which stood until both nations started launching space laboratories in the early 1970s.
 * On Gemini 8 (March 1966), Command Pilot Neil Armstrong achieved the first docking between two spacecraft, his Gemini craft and an Agena target vehicle.
 * Gemini 11 (September 1966), commanded by Conrad, achieved the first direct-ascent rendezvous with its Agena target on the first orbit, and used the Agena's rocket to achieve an apogee of 742 nmi, the manned Earth orbit record still current as of 2015.
 * On Gemini 12 (November 1966), Edwin E. "Buzz" Aldrin spent over five hours working comfortably during three (EVA) sessions, finally proving that humans could perform productive tasks outside their spacecraft. This proved to be the most difficult goal to achieve.

Most of the novice pilots on the early missions would command the later missions. In this way, Project Gemini built up spaceflight experience for the pool of astronauts for the Apollo lunar missions.

Soviet manned Moon programs
Korolev's design bureau produced two prospectuses for circumlunar spaceflight (March 1962 and May 1963), the main spacecraft for which were early versions of his Soyuz design. Soviet Communist Party Central Committee Command 655-268 officially established two secret, competing manned programs for circumlunar flights and lunar landings, on August 3, 1964. The circumlunar flights were planned to occur in 1967, and the landings to start in 1968. The circumlunar program (Zond), created by Vladimir Chelomey's design bureau OKB-52, was to fly two cosmonauts in a stripped-down Soyuz 7K-L1, launched by Chelomey's Proton UR-500 rocket. The Zond sacrificed habitable cabin volume for equipment, by omitting the Soyuz orbital module. Chelomey gained favor with Khruschev by employing members of his family.

Korolev's lunar landing program was designated N1/L3, for its N1 superbooster and a more advanced Soyuz 7K-L3 spacecraft, also known as the lunar orbital module ("Lunniy Orbitalny Korabl", LOK), with a crew of two. A separate lunar lander ("Lunniy Korabl", LK), would carry a single cosmonaut to the lunar surface.

The N1/L3 launch vehicle had three stages to Earth orbit, a fourth stage for Earth departure, and a fifth stage for lunar landing assist. The combined space vehicle was roughly the same height and takeoff mass as the three-stage US Apollo/ Saturn V and exceeded its takeoff thrust by 28%, but had only roughly half the translunar injection payload capability.

Following Khruschev's ouster from power, Chelomey's Zond program was merged into the N1/L3 program.

Outer space treaty
The US and USSR began discussions on the peaceful uses of space as early as 1958, presenting issues for debate to the United Nations, which created a Committee on the Peaceful Uses of Outer Space in 1959.

On May 10, 1962, Vice President Johnson addressed the Second National Conference on the Peaceful Uses of Space revealing that the United States and the USSR both supported a resolution passed by the Political Committee of the UN General Assembly on December 1962, which not only urged member nations to "extend the rules of international law to outer space," but to also cooperate in its exploration. Following the passing of this resolution, Kennedy commenced his communications proposing a cooperative American/Soviet space program.

The UN ultimately created a Treaty on Principles Governing the Activities of States in the Exploration and Use of Outer Space, including the Moon and Other Celestial Bodies, which was signed by the United States, USSR, and the United Kingdom on January 27, 1967 and went into force the following October 10.

This treaty:
 * bars party States from placing weapons of mass destruction in Earth orbit, on the Moon, or any other celestial body;
 * exclusively limits the use of the Moon and other celestial bodies to peaceful purposes, and expressly prohibits their use for testing weapons of any kind, conducting military maneuvers, or establishing military bases, installations, and fortifications;
 * declares that the exploration of outer space shall be done to benefit all countries and shall be free for exploration and use by all the States;
 * explicitly forbids any government from claiming a celestial resource such as the Moon or a planet, claiming that they are the common heritage of mankind, "not subject to national appropriation by claim of sovereignty, by means of use or occupation, or by any other means". However, the State that launches a space object retains jurisdiction and control over that object;
 * holds any State liable for damages caused by their space object;
 * declares that "the activities of non-governmental entities in outer space, including the Moon and other celestial bodies, shall require authorization and continuing supervision by the appropriate State Party to the Treaty", and "States Parties shall bear international responsibility for national space activities whether carried out by governmental or non-governmental entities"; and
 * "A State Party to the Treaty which has reason to believe that an activity or experiment planned by another State Party in outer space, including the Moon and other celestial bodies, would cause potentially harmful interference with activities in the peaceful exploration and use of outer space, including the Moon and other celestial bodies, may request consultation concerning the activity or experiment."

The treaty remains in force, signed by 102 member states. –

Disaster strikes both sides
In 1967, both nations faced serious challenges that brought their programs to temporary halts. Both had been rushing at full-speed toward the first piloted flights of Apollo and Soyuz, without paying due diligence to growing design and manufacturing problems. The results proved fatal to both pioneering crews.

On January 27, 1967, the same day the US and USSR signed the Outer Space Treaty, the crew of the first manned Apollo mission, Command Pilot Virgil "Gus" Grissom, Senior Pilot Edward H. White, and Pilot Roger Chaffee, were killed in a fire that swept through their spacecraft cabin during a ground test, less than a month before the planned February 21 launch. An investigative board determined the fire was probably caused by an electrical spark, and quickly grew out of control, fed by the spacecraft's pure oxygen atmosphere. Crew escape was made impossible by inability to open the plug door hatch cover against the greater-than-atmospheric internal pressure. The board also found design and construction flaws in the spacecraft, and procedural failings, including failure to appreciate the hazard of the pure-oxygen atmosphere, as well as inadequate safety procedures. All these flaws had to be corrected over the next twenty-two months until the first piloted flight could be made. Mercury and Gemini veteran Grissom had been a favored choice of Deke Slayton, NASA's Director of Flight Crew Operations, to make the first piloted landing.

On April 24, 1967, the single pilot of Soyuz 1, Vladimir Komarov, became the first in-flight spaceflight fatality. The mission was planned to be a three-day test, to include the first Soviet docking with an unpiloted Soyuz 2, but the mission was plagued with problems. Early on, Komarov's craft lacked sufficient electrical power because only one of two solar panels had deployed. Then the automatic attitude control system began malfunctioning and eventually failed completely, resulting in the craft spinning wildly. Komarov was able to stop the spin with the manual system, which was only partially effective. The flight controllers aborted his mission after only one day. During the emergency re-entry, a fault in the landing parachute system caused the primary chute to fail, and the reserve chute became tangled with the drogue chute; Komarov was killed on impact. Fixing the spacecraft faults caused an eighteen-month delay before piloted Soyuz flights could resume.

Onward to the Moon
The United States recovered from the Apollo 1 fire, fixing the fatal flaws in an improved version of the Block II command module. The US proceeded with unpiloted test launches of the Saturn V launch vehicle (Apollo 4 and Apollo 6) and the Lunar Module (Apollo 5) during the latter half of 1967 and early 1968. Apollo 1's mission to check out the Apollo Command/Service Module in Earth orbit was accomplished by Grissom's backup crew commanded by Walter Schirra on Apollo 7, launched on October 11, 1968. The eleven-day mission was a total success, as the spacecraft performed a virtually flawless mission, paving the way for the United States to continue with its lunar mission schedule.

The Soviet Union also fixed the parachute and control problems with Soyuz, and the next piloted mission Soyuz 3 was launched on October 26, 1968. The goal was to complete Komarov's rendezvous and docking mission with the un-piloted Soyuz 2. Ground controllers brought the two craft to within 200 m of each other, then cosmonaut Georgy Beregovoy took control. He got within 40 m of his target, but was unable to dock before expending 90 percent of his maneuvering fuel, due to a piloting error that put his spacecraft into the wrong orientation and forced Soyuz 2 to automatically turn away from his approaching craft. The first docking of Soviet spacecraft was finally realized in January 1969 by the Soyuz 4 and Soyuz 5 missions. It was the first-ever docking of two manned spacecraft, and the first transfer of crew from one space vehicle to another.

The Soviet Zond spacecraft was not yet ready for piloted circumlunar missions in 1968, after five unsuccessful and partially successful automated test launches: Cosmos 146 on March 10, 1967; Cosmos 154 on April 8, 1967; Zond 1967A September 27, 1967; Zond 1967B on November 22, 1967. Zond 4 was launched on March 2, 1968, and successfully made a circumlunar flight. After its successful flight around the Moon, Zond 4 encountered problems with its Earth reentry on March 9, and was ordered destroyed by an explosive charge 15000 m over the Gulf of Guinea. The Soviet official announcement said that Zond 4 was an automated test flight which ended with its intentional destruction, due to its recovery trajectory positioning it over the Atlantic Ocean instead of over the USSR.

During the summer of 1968, the Apollo program hit another snag: the first pilot-rated Lunar Module (LM) was not ready for orbital tests in time for a December 1968 launch. NASA planners overcame this challenge by changing the mission flight order, delaying the first LM flight until March 1969, and sending Apollo 8 into lunar orbit without the LM in December. This mission was in part motivated by intelligence rumors the Soviet Union might be ready for a piloted Zond flight during late 1968. In September 1968, Zond 5 made a circumlunar flight with tortoises on board and returned to Earth, accomplishing the first successful water landing of the Soviet space program in the Indian Ocean. It also scared NASA planners, as it took them several days to figure out that it was only an automated flight, not piloted, because voice recordings were transmitted from the craft en route to the Moon. On November 10, 1968 another automated test flight, Zond 6 was launched, but this time encountered difficulties in its Earth reentry, and depressurized and deployed its parachute too early, causing it to crash-land only 16 km from where it had been launched six days earlier. It turned out there was no chance of a piloted Soviet circumlunar flight during 1968, due to the unreliability of the Zonds.

On December 21, 1968, Frank Borman, James Lovell, and William Anders became the first humans to ride the Saturn V rocket into space on Apollo 8. They also became the first to leave low-Earth orbit and go to another celestial body, and entered lunar orbit on December 24. They made ten orbits in twenty hours, and transmitted one of the most watched TV broadcasts in history, with their Christmas Eve program from lunar orbit, that concluded with a reading from the biblical Book of Genesis. Two and a half hours after the broadcast, they fired their engine to perform the first trans-Earth injection to leave lunar orbit and return to the Earth. Apollo 8 safely landed in the Pacific ocean on December 27, in NASA's first dawn splashdown and recovery.

The American Lunar Module was finally ready for a successful piloted test flight in low Earth orbit on Apollo 9 in March 1969. The next mission, Apollo 10, conducted a "dress rehearsal" for the first landing in May 1969, flying the LM in lunar orbit as close as 47400 ft above the surface, the point where the powered descent to the surface would begin. With the LM proven to work well, the next step was to attempt the landing.

Unknown to the Americans, the Soviet Moon program was in deep trouble. After two successive launch failures of the N1 rocket in 1969, Soviet plans for a piloted landing suffered delay. The launch pad explosion of the N-1 on July 3, 1969 was a significant setback. The rocket hit the pad after an engine shutdown, destroying itself and the launch facility. Without the N-1 rocket, the USSR could not send a large enough payload to the Moon to land a human and return him safely.

Apollo 11
Apollo 11 was prepared with the goal of a July landing in the Sea of Tranquility. The crew, selected in January 1969, consisted of commander (CDR) Neil Armstrong, Command Module Pilot (CMP) Michael Collins, and Lunar Module Pilot (LMP) Edwin "Buzz" Aldrin. They trained for the mission until just before the launch day. On July 16, 1969, at exactly 9:32 am EDT, the Saturn V rocket, AS-506, lifted off from Kennedy Space Center Launch Complex 39 in Florida.

The trip to the Moon took just over three days. After achieving orbit, Armstrong and Aldrin transferred into the Lunar Module, named Eagle, and after a landing gear inspection by Collins remaining in the Command/Service Module Columbia, began their descent. After overcoming several computer overload alarms caused by an antenna switch left in the wrong position, and a slight downrange error, Armstrong took over manual flight control at about 180 m, and guided the Lunar Module to a safe landing spot at 20:18:04 UTC, July 20, 1969 (3:17:04 pm CDT). The first humans on the Moon waited six hours before they left their craft. At 02:56 UTC, July 21 (9:56 pm CDT July 20), Armstrong became the first human to set foot on the Moon.

The first step was witnessed by at least one-fifth of the population of Earth, or about 723 million people. His first words when he stepped off the LM's landing footpad were, "That's one small step for [a] man, one giant leap for mankind." Aldrin joined him on the surface almost 20 minutes later. Altogether, they spent just under two and one-quarter hours outside their craft. The next day, they performed the first launch from another celestial body, and rendezvoused back with Columbia.

Apollo 11 left lunar orbit and returned to Earth, landing safely in the Pacific Ocean on July 24, 1969. When the spacecraft splashed down, 2,982 days had passed since Kennedy's commitment to landing a man on the Moon and returning him safely to the Earth before the end of the decade; the mission was completed with 161 days to spare. With the safe completion of the Apollo 11 mission, the Americans won the race to the Moon.

The race winds down
NASA had ambitious follow-on human spaceflight plans as it reached its lunar goal, but soon discovered it had expended most of its political capital to do so.

The first landing was followed by another, precision landing on Apollo 12 in November 1969. NASA had achieved its first landing goal with enough Apollo spacecraft and Saturn V launchers left for eight follow-on lunar landings through Apollo 20, conducting extended-endurance missions and transporting the landing crews in Lunar Roving Vehicles on the last five. They also planned an Apollo Applications Program to develop a longer-duration Earth orbital workshop (later named Skylab) to be constructed in orbit from a spent S-IVB upper stage, using several launches of the smaller Saturn IB launch vehicle. But planners soon decided this could be done more efficiently by using the two live stages of a Saturn V to launch the workshop pre-fabricated from an S-IVB (which was also the Saturn V third stage), which immediately removed Apollo 20. Belt-tightening budget cuts soon led NASA to cut Apollo 18 and 19 as well, but keep three extended/Lunar Rover missions. Apollo 13 encountered an in-flight spacecraft failure and had to abort its lunar landing in April 1970, returning its crew safely but temporarily grounding the program again. It resumed with four successful landings on Apollo 14 (February 1971), Apollo 15 (July 1971), Apollo 16 (April 1972), and Apollo 17 (December 1972).

In February 1969, President Richard M. Nixon convened a Space Task Group to set recommendations for the future US civilian space program, headed by his Vice President Spiro T. Agnew. Agnew was an enthusiastic proponent of NASA's follow-on plans, and the STG recommended plans to develop a reusable Space Transportation System including a Space Shuttle, which would facilitate development of permanent space stations in Earth and lunar orbit, perhaps a base on the lunar surface, and the first human flight to Mars as early as 1986 or as late as 2000. Nixon had a better sense of the declining political support in Congress for a new Apollo-style program, which had disappeared with the achievement of the landing, and he intended to pursue detente with the USSR and China, which he hoped might ease Cold War tensions. He cut the spending proposal he sent to Congress to include funding for only the Space Shuttle, with perhaps an option to pursue the Earth orbital space station for the foreseeable future.

The USSR continued trying to perfect their N1 rocket, finally canceling it in 1976, after two more launch failures in 1971 and 1972.

Salyuts and Skylab
Having lost the race to the Moon, the USSR decided to concentrate on orbital space stations. During 1969 and 1970, they launched six more Soyuz flights after Soyuz 3, then launched the first space station, the Salyut 1 laboratory designed by Kerim Kerimov, on April 19, 1971. Three days later, the Soyuz 10 crew attempted to dock with it, but failed to achieve a secure enough connection to safely enter the station. The Soyuz 11 crew of Vladislav Volkov, Georgi Dobrovolski and Viktor Patsayev successfully docked on June 7, and completed a record 22-day stay. The crew became the second in-flight space fatality during their reentry on June 30. They were asphyxiated when their spacecraft's cabin lost all pressure, shortly after undocking. The disaster was blamed on a faulty cabin pressure valve, that allowed all the air to vent into space. The crew was not wearing pressure suits and had no chance of survival once the leak occurred.

Salyut 1's orbit was increased to prevent premature reentry, but further piloted flights were delayed while the Soyuz was redesigned to fix the new safety problem. The station re-entered the Earth's atmosphere on October 11, after 175 days in orbit. The USSR attempted to launch a second Salyut-class station designated Durable Orbital Station-2 (DOS-2) on July 29, 1972, but a rocket failure caused it to fail to achieve orbit. After the DOS-2 failure, the USSR attempted to launch four more Salyut-class stations up to 1975, with another failure due to an explosion of the final rocket stage, which punctured the station with shrapnel so that it would not hold pressure. All of the Salyuts were presented to the public as non-military scientific laboratories, but some of them were covers for the military Almaz reconnaissance stations.

The United States launched the orbital workstation Skylab 1 on May 14, 1973. It weighed 169950 lb, was 58 ft long by 21.7 ft in diameter, with a habitable volume of 10000 ft3. Skylab was damaged during the ascent to orbit, losing one of its solar panels and a meteoroid thermal shield. Subsequent manned missions repaired the station, and the final mission's crew, Skylab 4, set the Space Race endurance record with 84 days in orbit when the mission ended on February 8, 1974. Skylab stayed in orbit another five years before reentering the Earth's atmosphere over the Indian Ocean and Western Australia on July 11, 1979.

Apollo–Soyuz Test Project
In May 1972, President Richard M. Nixon and Soviet Premier Leonid Brezhnev negotiated an easing of relations known as detente, creating a temporary "thaw" in the Cold War. In the spirit of good sportsmanship, the time seemed right for cooperation rather than competition, and the notion of a continuing "race" began to subside.

The two nations planned a joint mission to dock the last US Apollo craft with a Soyuz, known as the Apollo-Soyuz Test Project (ASTP). To prepare, the US designed a docking module for the Apollo that was compatible with the Soviet docking system, which allowed any of their craft to dock with any other (e.g. Soyuz/Soyuz as well as Soyuz/Salyut). The module was also necessary as an airlock to allow the men to visit each other's craft, which had incompatible cabin atmospheres. The USSR used the Soyuz 16 mission in December 1974 to prepare for ASTP.

The joint mission began when Soyuz 19 was first launched on July 15, 1975 at 12:20 UTC, and the Apollo craft was launched with the docking module six and a half hours later. The two craft rendezvoused and docked on July 17 at 16:19 UTC. The three astronauts conducted joint experiments with the two cosmonauts, and the crew shook hands, exchanged gifts, and visited each other's craft.

Human spaceflight after Apollo
In the 1970s, the United States began developing a new generation of reusable orbital spacecraft known as the Space Shuttle, and launched a range of unmanned probes. The USSR continued to develop space station technology with the Salyut program and Mir ('Peace' or 'World', depending on the context) space station, supported by Soyuz spacecraft. They developed their own large space shuttle under the Buran program. The USSR dissolved in 1991 and the remains of its space program mainly passed to Russia. The United States and Russia worked together in space with the Shuttle–Mir Program, and again with the International Space Station.

The Russian R-7 rocket family, which launched the first Sputnik at the beginning of the space race, is still in use today. It services the International Space Station (ISS) as the launcher for both the Soyuz and Progress spacecraft. It also ferries both Russian and American crews to and from the station.