Space Race

Soon after the end of World War II, the two former allies became engaged in a state of political conflict and military tension known as the Cold War (1947–1991), which polarized Europe between the Soviet Union's satellite states (often referred to as the Eastern Bloc) and the states of the Western world allied with the U.S.[17]

The Soviet stable of Sputnik, Vostok, Voskhod, and Soyuz launch vehicles were all derivatives of the R-7 Semyorka ICBM.

The first Soviet development of artillery rockets was in 1921 when the Soviet military sanctioned the Gas Dynamics Laboratory, a small research laboratory to explore solid fuel rockets, led by Nikolai Tikhomirov, who had begun studying solid and liquid-fueled rockets in 1894, and obtained a patent in 1915 for "self-propelled aerial and water-surface mines.[18][19] The first test-firing of a solid fuel rocket was carried out in 1928.[20]

Further development was carried out in the 1930s by the Group for the Study of Reactive Motion (GIRD), where Soviet rocket pioneers Sergey Korolev, Friedrich Zander, Mikhail Tikhonravov and Leonid Dushkin[21] launched GIRD-X, the first Soviet liquid-fueled rocket in 1933.[22] In 1933 the two design bureaus were combined into the Reactive Scientific Research Institute[23] and produced the RP-318, the USSR's first rocket-powered aircraft and the RS-82 and RS-132 missiles,[24] which became the basis for the Katyusha multiple rocket launcher,[25][26] During the 1930s Soviet rocket technology was comparable to Germany's,[27] but Joseph Stalin's Great Purge from 1936 to 1938 severely damaged its progress.

In 1944 the Soviets became aware of Nazi Germany's rocket program from Winston Churchill, which resulted in recovery of V-2 rocket parts from a missile test station in Debica, Poland.[28] In early 1945 a team of Soviet rocket specialists were sent to Germany to identify and recover German rocket technology,[29] which developed into Institute Rabe, a Soviet missile research group in Bleicherode, Germany that recruited and employed German rocket specialists to aid in current and future Soviet rocket development.[30] In 1946 Operation Osoaviakhim moved more than 170 of the top German rocket specialists to the Soviet Union.[31] In 1945 and 1946 the use of German expertise was invaluable in reducing the time needed to master the intricacies of the V-2 rocket, establishing production of the R-1 rocket and enable a base for further developments. However, after 1947 the Soviets made very little use of German specialists and their influence on the future Soviet rocket program was marginal.[32][33] The Germans were eventually repatriated in 1951-53.[34]

Having suffered at least 27 million casualties during World War II after being invaded by Nazi Germany in 1941,[35] the Soviet Union was wary of the United States, which until late 1949 was the sole possessor of atomic weapons. 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.[36] In 1953, Korolev was given the go-ahead to develop the R-7 Semyorka rocket. It was successfully tested on August 21, 1957, and became the world's first fully operational ICBM the following month.[37] It was later used to launch the first satellite into space, and derivatives launched all piloted Soviet spacecraft.[38]

Wernher von Braun became the United States' lead rocket engineer during the 1950s and 1960s.

Although American rocket pioneer Robert H. Goddard developed, patented, and flew small liquid-propellant rockets as early as 1914, he became a recluse when his ideas were ridiculed by an editorial in The New York Times. This left the United States as the only one of the major three World War II powers not to have its own rocket program, until Von Braun and his engineers were expatriated from Nazi Germany in 1945. The US acquired a large number of V-2 rockets and recruited von Braun and most of his engineering team in Operation Paperclip.[39] The team was sent to the Army's White Sands Proving Ground in New Mexico, in 1945.[40] They set about assembling the captured V-2s and began a program of launching them and instructing American engineers in their operation.[41] These tests led to the first photos of Earth from space, and the first two-stage rocket, the WAC Corporal-V-2 combination, in 1949.[41] The German rocket team was moved from Fort Bliss to the Army's new Redstone Arsenal, located in Huntsville, Alabama, in 1950.[42] From here, von Braun and his team developed the Army's first operational medium-range ballistic missile, the Redstone rocket, derivatives of which launched both America's first satellite, and the first piloted Mercury space missions.[42] It became the basis for both the Jupiter and Saturn family of rockets.[42]

The US stable of Explorer 1, Mercury, Gemini, and Apollo launch vehicles were a varied group of ICBMs and the NASA-developed Saturn IB rocket.

Each of the United States armed services had its own ICBM development program. The Air Force began ICBM research in 1945 with the MX-774.[43] In 1950, von Braun began testing the Air Force PGM-11 Redstone rocket family at Cape Canaveral.[44] By 1957, a descendant of the Air Force MX-774 received top-priority funding.[43] and evolved into the Atlas-A, the first successful American ICBM.[43] Its upgraded version, the Atlas-D, 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.[43]

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.[3] The Council of Ministers of the Soviet Union began a policy of treating development of its space program as top-secret. When the Sputnik project was first approved, one of the immediate courses of action the Politburo took was to consider what to announce to the world regarding their event. The Telegraph Agency of the Soviet Union (TASS) established precedents for all official announcements on the Soviet space program. The information eventually released did not offer details on who built and launched the satellite or why it was launched. However, the public release is illuminating in what it does reveal: "there is an abundance of arcane scientific and technical data... as if to overwhelm the reader with mathematics in the absence of even a picture of the object".[45]

The Soviet space program's use of secrecy served as both a tool to prevent the leaking of classified information between countries, and also to create a mysterious barrier between the space program and the Soviet populace. The program's nature embodied ambiguous messages concerning its goals, successes, and values. The program itself was so secret that a regular Soviet citizen could never achieve a concrete image of it, but rather a superficial picture of its history, present activities, or future endeavors. Launchings were not announced until they took place. Cosmonaut names were not released until they flew. Mission details were sparse. Outside observers did not know the size or shape of their rockets or cabins or most of their spaceships, except for the first Sputniks, lunar probes, and Venus probe.[46]

The Soviet military maintained control over the space program; Korolev's OKB-1 design bureau was subordinated under the Ministry of General Machine Building,[45] tasked with the development of intercontinental ballistic missiles, and continued to give its assets random identifiers into the 1960s.[45] They cloaked the program in a shroud of secrecy; public pronouncements were uniformly positive. As far as the public knew, the Soviet space program had never experienced failure. According to historian James Andrews, "With almost no exceptions, coverage of Soviet space exploits, especially in the case of human space missions, omitted reports of failure or trouble".[45]

Dominic Phelan says in the book Cold War Space Sleuths (Springer-Praxis 2013): "The USSR was famously described by Winston Churchill as 'a riddle, wrapped in a mystery, inside an enigma' and nothing signified this more than the search for the truth behind its space program during the Cold War. Although the Space Race was literally played out above our heads, it was often obscured by a figurative 'space curtain' that took much effort to see through".[46]

Initially, President Eisenhower was worried that a satellite passing above a nation at over 100 kilometers (62 mi) might be seen as violating that nation's airspace.[47] He was concerned that the Soviet Union would accuse the Americans of an illegal overflight, thereby scoring a propaganda victory at his expense.[48] Eisenhower and his advisors were of the opinion that a nation's airspace sovereignty did not extend past the Kármán line, and they used the 1957–58 International Geophysical Year launches to establish this principle in international law.[47] 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 rocket.[49] 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.[49] 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 reentry vehicle technology.[49]

Korolev received word about von Braun's 1956 Jupiter-C test and, mistakenly thinking it was a satellite mission that failed, expedited plans to get his own satellite in orbit. Since the R-7 was substantially more powerful than any of the US launch vehicles, he made sure to take full advantage of this capability by designing Object D as his primary satellite.[50] 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.[51] Object D dwarfed the proposed US satellites, having a weight of 1,400 kilograms (3,100 lb), of which 300 kilograms (660 lb) would be composed of scientific instruments that would photograph the Earth, take readings on radiation levels, and check on the planet's magnetic field.[51] 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 build a Prosteishy Sputnik (PS-1), or simple satellite.[50] The council also decreed that Object D be postponed until April 1958.[52] The new Sputnik was a metallic sphere that would be a much lighter craft, weighing 83.8 kilograms (185 lb) and having a 58-centimeter (23 in) diameter.[53] 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.[54]

Replica of the first artificial satellite Sputnik 1, 1957

Korolev was buoyed by the first successful launches of the R-7 rocket in August and September, which paved the way for the launch of Sputnik.[55] Word came that the US was 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 titled "Satellite Over the Planet", on October 6, 1957.[56] 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.[56] He hastened the launch, moving it to October 4.[56] 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.[55] It arrived at the Soviet missile base Tyura-Tam in September and was prepared for its mission at launch site number one.[55] The first launch took place on Friday, October 4, 1957 at exactly 10:28:34 pm Moscow time, with the R-7 and the now named Sputnik 1 satellite lifting off the launch pad and placing the artificial "moon" into an orbit a few minutes later.[57] 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.[57] 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.[58]

At the latest, the successful start of Sputnik 2 with its weight of more than 500 kg proved that the USSR had achieved a leading advantage in rocket technology. The dumbfounded CIA estimated the launch weight at 500 metric tons requiring an initial thrust of more than 1,000 tons and supposed the use of a three-stage rocket. In a secret report, it concluded that ″the launching of two earth satellites must have been a stupendous scientific achievement. … Launching of these satellites does indicate, however, that the USSR has perfected an ICBM which they can put on any desired target with accuracy." [59], In reality, the launch weight of the Soviet rocket was 267 metric tons with an initial thrust of 410 tons with one and a half stages. The CIA's misjudgement was caused by extrapolating the parameters of the US Atlas rocket developed at the same time (launch weight 82 tons, initial thrust 135 tones, maximum payload of 70 kg for low Earth orbit).[60] In part, the favourable data of the Soviet launcher was based on concepts proposed by the German rocket scientists headed by Helmut Gröttrup on Gorodomlya Island, such as, among other things, the rigorous weight saving, the control of the residual fuel quantities and a reduced thrust to weight relation of 1.4 instead of usual factor 2.[61] The CIA had heard about such details already in January 1954 when it interrogated Göttrup after his return from the USSR but did not take him seriously.[62]

William Hayward Pickering, James Van Allen, and Wernher von Braun display a full-scale model of Explorer 1 at a Washington, DC news conference after confirmation the satellite was in orbit.

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."[63]

Eisenhower ordered project Vanguard to move up its timetable and launch its satellite much sooner than originally planned.[64] The December 6, 1957 Project Vanguard launch failure occurred at Cape Canaveral Air Force Station in Florida. 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,[65] and Dudnik.[66] In the United Nations, the Soviet delegate offered the US representative aid "under the Soviet program of technical assistance to backwards nations."[65] 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.[67] The Daily Express predicted that the US would catch up to and pass the USSR in space; "never doubt for a moment that America would be successful".[68]

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.[69] The satellite Explorer 1 was 30.66 pounds (13.91 kg) in mass.[69] The payload of Explorer 1 weighed 18.35 pounds (8.32 kg). It carried a micrometeorite gauge and a Geiger-Müller tube. It passed in and out of the Earth-encompassing radiation belt with its 194-by-1,368-nautical-mile (360 by 2,534 km) orbit, therefore saturating the tube's capacity and proving what Dr. James Van Allen, a space scientist at the University of Iowa, had theorized.[69] 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.[70] 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.[71] 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, appointed by the President, responsible for coordinating the nation's civilian and military space programs.[72]

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.[73]

Replica of the Zenit and Vostok spacecraft bus

The Soviets designed their first human space capsule using the same spacecraft bus as their Zenit spy satellite,[89] forcing them to keep the details and true appearance secret until after the Vostok program was over. The craft consisted of a spherical descent module with a mass of 2.46 tonnes (5,400 lb) and a diameter of 2.3 meters (7.5 ft), with a cylindrical inner cabin housing the cosmonaut, instruments, and escape system; and a biconic instrument module with a mass of 2.27 tonnes (5,000 lb), 2.25 meters (7.4 ft) long and 2.43 meters (8.0 ft) in diameter, containing the engine system and propellant. After reentry, the cosmonaut would eject at about 7,000 meters (23,000 ft) over the USSR and descend via parachute, while the capsule would land separately, because the descent module made an extremely rough landing that could have left a cosmonaut seriously injured.[90] The "Vostok spaceship" was first displayed at the July 1961 Tushino air show, mounted on its launch vehicle's third stage, with the nose cone in place concealing the spherical capsule. A tail section with eight fins was added in an apparent attempt to confuse western observers. This also appeared on official commemorative stamps and a documentary.[91] The Soviets finally revealed the true appearance of their Vostok capsule at the April 1965 Moscow Economic Exhibition.

Yuri Gagarin, the first person in space, 1961

On April 12, 1961, the USSR surprised the world by launching Yuri Gagarin into a single, 108-minute orbit around the Earth in a craft called Vostok 1.[90] They dubbed Gagarin the first cosmonaut, roughly translated from Russian and Greek as "sailor of the universe". Gagarin's capsule was flown in automatic mode, since doctors did not know what would happen to a human in the weightlessness of space; but Gagarin was given an envelope containing the code that would unlock manual control in an emergency.[90]

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.[92] April 12 was declared Cosmonautics Day in the USSR, and is celebrated today in Russia as one of the official "Commemorative Dates of Russia."[93] In 2011, it was declared the International Day of Human Space Flight by the United Nations.[94]

The USSR demonstrated 24-hour launch pad turnaround and launched two piloted spacecraft, Vostok 3 and Vostok 4, in essentially identical orbits, on August 11 and 12, 1962.[95] The two spacecraft came within approximately 6.5 kilometers (3.5 nautical miles) of one another, close enough for radio communication,[96] but then drifted as far apart as 2,850 kilometers (1,540 nautical miles). The Vostok had no maneuvering rockets to keep the two craft a controlled distance apart.[97] Vostok 4 also set a record of nearly four days in space. The first woman, Valentina Tereshkova, was launched into space on Vostok 6 on June 16, 1963,[98] as (possibly) a medical experiment. She was the only one to fly of a small group of female parachutist factory workers (unlike the male cosmonauts who were military test pilots),[99] chosen by the head of cosmonaut training because he read a tabloid article about the "Mercury 13" group of women wanting to become astronauts, and got the mistaken idea that NASA was actually entertaining this.[100][98] Five months after her flight, Tereshkova married Vostok 3 cosmonaut Andriyan Nikolayev,[101] and they had a daughter.[102]

Cutaway of the Mercury capsule

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's Space Task Group and renamed Project Mercury on November 26, 1958. The Mercury spacecraft was designed by the STG's chief engineer Maxime Faget. 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 unpiloted, then carry a non-human primate, then finally humans.

The Mercury spacecraft's principal designer was Maxime Faget, who started research for human spaceflight during the time of the NACA.[103] It consisted of a conical capsule with a cylindrical pack of three solid-fuel retro-rockets strapped over a beryllium or fiberglass heat shield on the blunt end. Base diameter at the blunt end was 6.0 feet (1.8 m) and length was 10.8 feet (3.3 m); with the launch escape system added, the overall length was 25.9 feet (7.9 m).[104] With 100 cubic feet (2.8 m³) of habitable volume, the capsule was just large enough for a single astronaut.[105] The first suborbital spacecraft weighed 3,000 pounds (1,400 kg); the heaviest, Mercury-Atlas 9, weighed 3,000 pounds (1,400 kg) fully loaded.[106] On reentry, the astronaut would stay in the craft through splashdown by parachute in the Atlantic Ocean.

Alan Shepard, the first American in space, 1961

On May 5, 1961, Alan Shepard became the first American in space, launching in a ballistic trajectory on Mercury-Redstone 3, in a spacecraft he named Freedom 7.[107] 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.[108] 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.[109]

John Glenn, the first American in orbit, 1962

American Virgil "Gus" Grissom repeated Shepard's suborbital flight in Liberty Bell 7 on July 21, 1961.[110] 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.[111] 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.[111] On February 23, 1962, President Kennedy awarded Glenn with the NASA Distinguished Service Medal in a ceremony at Cape Canaveral Air Force Station.[112] 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.

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.[113]

After a first US-USSR Dryden-Blagonravov agreement and cooperation on the Echo II balloon satellite in 1962,[12] President Kennedy proposed on September 20, 1963, in a speech before the United Nations General Assembly, that the United States and the Soviet Union join forces in an effort to reach the Moon.[123] Kennedy thus changed his mind regarding the desirability of the space race, preferring instead to ease tensions with the Soviet Union by cooperating on projects such as a joint lunar landing.[124] Soviet Premier Nikita Khrushchev initially rejected Kennedy's proposal.[125] However, 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.[125]

Some cooperation in robotic space exploration nevertheless did take place,[126] such as a combined Venera 4–Mariner 5 data analysis under a joint Soviet–American working group of COSPAR in 1969, allowing a more complete drawing of the profile of the atmosphere of Venus.[127][128] Eventually the Apollo-Soyuz mission was realized afterall, which furthermore laid the foundations for the Shuttle-Mir program and the ISS.

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 Executive Order 11129 renaming the Cape Canaveral and Apollo launch facilities after Kennedy.

Korolev modified the one-person Vostok capsule into carrying three people, or two plus an airlock for spacewalk capability.

Korolev's conversion of his surplus Vostok capsules to the Voskhod spacecraft allowed the Soviet space program to beat the Gemini program in achieving the first spaceflight with a multi-person crew, and the first "spacewalk". Gemini took a year longer than planned to make its first flight, so Voskhod 1 became the first spaceflight with a three-person crew on October 12, 1964.[134] The USSR touted another "technological achievement" during this mission: it was the first space flight during which cosmonauts performed in a shirt-sleeve-environment.[135] However, flying without spacesuits was not due to safety improvements in the Soviet spacecraft's environmental systems; rather this was 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.[135] This was not repeated until the US Apollo Command Module flew in 1968; the command module cabin was designed to transport three astronauts in a low pressure, pure oxygen shirt-sleeve environment while in space.

On March 18, 1965, about a week before the first piloted Project Gemini space flight, the USSR launched the two-cosmonaut Voskhod 2 mission with Pavel Belyayev and Alexei Leonov.[136] 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.[137] Leonov performed the first-ever EVA as part of the mission.[136] A fatality was narrowly avoided when Leonov's spacesuit expanded in the vacuum of space, preventing him from re-entering the airlock.[138] In order to overcome this, he had to partially depressurize his spacesuit to a potentially dangerous level.[138] He succeeded in safely re-entering the spacecraft, 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.[139] The reentry involved two more challenges: an improperly timed retrorocket firing caused the Voskhod 2 to land 386 kilometers (240 mi) off its designated target area, the city of Perm; and the instrument compartment's failure to detach from the descent apparatus caused the spacecraft to become unstable during reentry.[139]

By October 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".[140] 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 reaching the Moon.[141] Voskhod 2 ended up being Korolev's final achievement before his death on January 14, 1966, as it became the last of the space firsts that the USSR achieved 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."[4] There was a two-year pause in Soviet piloted space flights while Voskhod's replacement, the Soyuz spacecraft, was designed and developed.<[142]

Rendezvous of Gemini 6 and 7, December 1965

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 superiority in piloted spaceflight. Gemini had ten crewed missions between March 1965 and November 1966: Gemini 3, Gemini 4, Gemini 5, Gemini 6A, Gemini 7, Gemini 8, Gemini 9A, Gemini 10, Gemini 11, and Gemini 12; and accomplished the following:

• Every mission demonstrated the ability to change the craft's orbit.
• Gemini 5 demonstrated eight-day endurance, long enough for a round trip to the Moon. Gemini 7 demonstrated a fourteen-day endurance flight.
• Gemini 6A demonstrated rendezvous and station-keeping with Gemini 7 for three consecutive orbits at distances as close as 1 foot (0.30 m).[143] Gemini 9A also achieved rendezvous with an Agena Target Vehicle (ATV).
• Rendezvous and docking with the ATV was achieved on Gemini 8, 10, 11, and 12. Gemini 11 achieved the first direct-ascent rendezvous with its Agena target on the first orbit.
• Extravehicular activity (EVA) was perfected through increasing practice on Gemini 4, 9A, 10, 11, and 12. On Gemini 12, Edwin "Buzz" Aldrin spent over five hours working comfortably during three (EVA) sessions, finally proving that humans could perform productive tasks outside their spacecraft.
• Gemini 10, 11, and 12 used the ATV's engine to make large changes in its orbit while docked. Gemini 11 used the Agena's rocket to achieve a crewed Earth orbit record apogee of 742 nautical miles (1,374 km).

Gemini 8 experienced the first in-space mission abort on March 17, 1966, just after achieving the world's first docking, when a stuck or shorted thruster sent the craft into an uncontrolled spin. Command pilot Neil Armstrong was able to shut off the stuck thruster and stop the spin by using the re-entry control system.[144] He and his crewmate David Scott landed and were recovered safely.[145]

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. With the completion of Gemini, the US had demonstrated all the technologies necessary to make Kennedy's goal of landing a man on the Moon, with the exception of developing a large enough launch vehicle.

Progress in the Space Race, showing the US passing the Soviets in 1965

Charred interior of the Apollo 1 spacecraft after the fire that killed the crew

On January 27, 1967, the same day the US and USSR signed the Outer Space Treaty, the crew of the first crewed Apollo mission, Command Pilot Virgil "Gus" Grissom, Senior Pilot Ed 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 atmosphere of pure oxygen at greater than one standard atmosphere. Crew escape was made impossible by inability to open the plug door hatch cover against the internal pressure.[156] 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.[156] All these flaws had to be corrected over the next twenty-two months until the first piloted flight could be made.[156] 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.[157]

Commemorative plaque and the Fallen Astronaut sculpture left on the Moon in 1971 by the crew of Apollo 15 in memory of 14 deceased NASA astronauts and USSR cosmonauts

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, causing descent speed to reach as high as 40 m/s (140 km/h; 89 mph). Shortly thereafter, Soyuz 1 impacted the ground 3 km (1.9 mi) west of Karabutak, exploding into a ball of flames. The official autopsy states Komarov died of blunt force trauma on impact, and that the subsequent heat mutilation of his corpse was a result of the explosive impact. Fixing the spacecraft's faults caused an eighteen-month delay before piloted Soyuz flights could resume.

The Soyuz 11 crew with the Salyut station in the background, in a Soviet commemorative stamp

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 and then launched a series of six successful space stations (plus two failures to achieve orbit and one station rendered uninhabitable due to damage from explosion of the launcher's upper stage) on their Proton-K heavy-lift launcher in their Salyut program designed by Kerim Kerimov. Each one weighed between 18,500 and 19,824 kilograms (40,786 and 43,704 lb), was 20 meters (66 ft) long by 4 meters (13 ft) in diameter, and had a habitable volume of 99 cubic meters (3,500 cu ft). All of the Salyuts were presented to the public as non-military scientific laboratories, but three of them were covers for military Almaz reconnaissance stations: Salyut 2 (failed),[201] Salyut 3,[202] and Salyut 5.

Salyut 1, the first space station, was launched by the Soviets 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.[203]

The United States launched a single orbital workstation, Skylab, on May 14, 1973. It weighed 169,950 pounds (77,090 kg), was 58 feet (18 m) long by 21.7 feet (6.6 m) in diameter, and had a habitable volume of 10,000 cubic feet (280 m³). Skylab was damaged during the ascent to orbit, losing one of its solar panels and a meteoroid thermal shield. Subsequent crewed missions repaired the station, and the third and final mission's crew, Skylab 4, set a human endurance record (at the time) 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.[204]

Salyut 4 broke Skylab's occupation record at 92 days. Salyut 6 and Salyut 7 were second-generation stations designed for long duration, and were occupied for 683 and 816 days.

Apollo-Soyuz crew: From left to right: Donald "Deke" Slayton, Thomas Patten Stafford, Vance Brand, Alexei Leonov, and Valeri Kubasov

American Stafford and Russian Leonov shake hands in space aboard the Apollo–Soyuz docking adapter.

In May 1972, President Richard M. Nixon and Soviet Premier Leonid Brezhnev negotiated an easing of relations known as détente, creating a temporary "thaw" in the Cold War. 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-to-Soyuz as well as Soyuz-to-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 test modifications of the Soyuz atmosphere and the docking adapter to prepare for ASTP.[205][206]

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.[207]

Soyuz, US Space Shuttle, and Energia-Buran

NASA achieved the first approach and landing test of its Space Shuttle orbiter on a Boeing 747 carrier plane on August 12, 1977, and the first orbital test flight of a complete, crewed Space Shuttle, consisting of the orbiter, an external fuel tank, and two solid rocket boosters, on April 12, 1981. The designers underestimated the time and cost of refurbishment between flights, which reduced the cost benefit of its reusability. They also overestimated its safety: two of the fleet of five orbiters were lost in fatal flight accidents: one during launch, due to failure of a solid rocket booster seal; and one on reentry, due to launch damage of a wing heat shield. The Air Force was also supposed to use the Shuttle to launch its military payloads, but shunned it in favor of its expendable launchers after the first Shuttle loss. NASA ceased production of its Apollo spacecraft and Saturn IB launcher, and used the Shuttle as its orbital workhorse until 2011, then retired it due to the safety concern. Originally, more than 150 flights over a 15-year operation were expected; actually, the Shuttle made 135 flights in its 30-year lifespan.

The Soviets mistook the Shuttle as a military surveillance vehicle and decided they had to develop their own shuttle, which they named Buran, beginning in 1974. They copied the aerodynamic design of NASA's Shuttle orbiter, which they strapped to the side of their expendable, liquid hydrogen-fueled Energia launcher. The Buran could be fitted with four Saturn AL-31 turbofan engines and a fuel tank in its payload bay, allowing it to make its own atmospheric test flights, which began in November 1985. Also unlike the US Shuttle, it could be flown pilotlessly and landed automatically. Energia-Buran made only one orbital test flight in November 1988, but US counterintelligence baited the Soviets with disinformation about the heat shield design, and it was not reusable for repeated flight.[208] Buran was the largest and most expensive Soviet program in the history of the Space Race,[209] and was effectively canceled by the collapse of the Soviet Union in 1991, due to lack of funding. The Energia was also canceled at the same time, after only two flights.

The first woman in space was from the Soviet Union, Valentina Tereshkova. NASA did not welcome female astronauts into its corps until 1978, when six female mission specialists were recruited. This first class included scientist Sally Ride, who became America's first woman in space on STS-7 in June 1983. NASA included women mission specialists in the next four astronaut candidate classes, and admitted female pilots starting in 1990. Eileen Collins from this class became the first pilot to fly on Space Shuttle flight STS-63 in February 1995, and the first female commander of a spaceflight on STS-93 in July 1999.

The USSR admitted its first female test pilot as a cosmonaut, Svetlana Savitskaya, in 1980. She became the first female to fly since Tereshkova, on Salyut 7 in December 1981.

The USSR turned its space program to the development of the low Earth orbit modular space station Mir (peace or world) assembled in orbit from 1986 to 1996. At 129,700 kilograms (285,900 lb), it held records for the largest spacecraft and the longest continuous human presence in space at 3,644 days, until the International Space Station was built starting in 1998.[210] Mir's operation continued after the 1991 replacement of the USSR's space program with the Russian Federal Space Agency until 2001, supported by Soyuz spacecraft.