Space travel didn’t become feasible until the twentieth century. Rocket technology, which would become the basis of all space travel, began with the rocket development work of Konstantin Tsiolkovsky (1857–1935) in Russia and Robert Goddard (1882–1945) in the United States. The Chinese had invented a rocket weapon in 1232 using gunpowder, which was ultimately adopted in technologically sophisticated societies throughout the world. During the eighteenth and nineteenth centuries, various pioneers improved the rocket’s effectiveness as a weapon. It is Tsiolkovsky of Czarist Russia, however, who is remembered as the “father of astronautics.” Although he dealt with many aspects of the rocket as an instrument of interplanetary travel, his most important contributions concerned propellants and the rocket design needed to achieve flight into the Earth’s orbit and then farther into space. In particular, he discussed the possibility of powerful, controllable liquid propellants, such as hydrogen and oxygen, and multistage rockets. Although Tsiolkovsky accurately predicted many future developments, his writings were not widely read during his life.

The work of the U.S. physicist Robert Goddard also concerned multistage rockets and liquid propellants. In 1926 at a farm in Auburn, Massachusetts, Goddard used liquid oxygen and petrol to send the first liquid-propelled rocket into the air at a rate of 60 miles per hour. He continued his experiments, with a launch in 1935 ultimately achieving 1,000 feet and a speed of 700 mph. Despite his genius and some financial support from the U.S. government, the reticent and publicity-shy Goddard did not contribute directly to the American space program. However, his reticence paved the way for the Transylvanian and German rocket and space travel visionary, Hermann Oberth (1894–1989), who corresponded with Goddard. Like Tsiolkovsky, Oberth dealt with both detailed engineering and the broader issues regarding space exploration. He helped to spread popular awareness of the rocket and the possibilities of space travel throughout Germany. In the 1920s and 1930s, various rocket societies in Europe and the United States, which included engineers as well as visionaries, met to build rockets as well as to advance their general knowledge of space travel.

Meanwhile, leaders in the USSR, building on Tsiolkovsky’s ideas, formed a military organization in 1928 under young engineer Valentin Glushko (1908–1989). The laboratory, called the Gas Dynamics Laboratory (GDL), built solid-fuel war rockets. In 1931, Soviet leaders gained control of another key organization, the Group for the Study of Reaction Motion (known in the USSR as GIRD), which emphasized more powerful liquid-fuel rockets. GIRD had emerged from a core of Soviet engineers and space enthusiasts who dreamed of going to the moon and beyond. The Red Army funded this group as well as GDL. Sergei Korolev (1906–1966), the future mastermind behind the Soviet space program, was one of GIRD’s most enthusiastic members. During this era, Korolev focused on rocket aircraft and honed his organizational skills. Through the efforts of GIRD, the USSR launched its first liquid-fuel rocket in 1933. Its success caused Soviet leaders to take a greater interest in the use of rocket technology in weaponry. Ultimately, leaders consolidated GIRD and GDL into a single organization, RN-II, which made further contributions to rocket development. The tragic advent of Stalin’s purges in 1934 threatened the nascent Soviet rocket program. Many Soviet rocket pioneers and space visionaries perished in the purges. Stalin’s police imprisoned both Korolev and Glushko, but they managed to survive, working as state prisoners to advance rocketry.

In Germany, the state also harnessed space enthusiasts for military purposes. The most notable of these was Wernher von Braun (1912–1977), who would play a vital role in the United States space program as well as in the German rocket program. Born to a prominent family, von Braun was active in the VfR (Society for Space Ship Travel). He joined the German Army Ordnance Department in 1932 to work on a liquid-fuel rocket with a range greater than any preexisting artillery. In 1937, the group moved to Peenemunde, a new proving ground on the Baltic. Von Braun, who was talented as a manager as well as an engineer, led the rocket development program.

Although the Nazi leadership supported the program only erratically, von Braun and his associates made progress as they dreamed of future trips to the moon and Mars. The V-2/A-4 rocket, or “vengeance weapon,” first flew in late 1942. It was much more powerful than any preceding rocket, standing almost fifty feet high, weighing 28,000 pounds, reaching a height of sixty miles, and carrying a heavy bomb. It burned liquid oxygen and ethyl alcohol and had sophisticated guidance and control systems. This rocket was an ancestor to many American rockets, including the powerful Saturn V which would take the first humans to the moon. Workers enslaved by Hitler built most of the V-2 rockets used in World War II. Although the weapons were not accurate, their victims had few defenses against them. In September of 1944, Hitler launched a V-2 bombardment against targets in southern England and liberated Europe. While powerful, these weapons made little difference to the war’s final outcome.

Remains of an ancient observatory at Chichén Itzá, Mexico. Photo by Chris Howell.

To see far is one thing, going there is another.

Constantin Brancusi (1876–1957)

As the Cold War between the United States and the Soviet Union intensified after World War II, both the Americans and the Soviets utilized the survivors of Nazi Germany’s military rocket teams. Stalin’s rocket program, approved in 1947, was intended to culminate in the production of an Intercontinental Ballistic Missile (ICBM). The Soviet army recreated the V-2 rocket through the SS-I and SS-II rockets, but the Soviet aviation industry avoided rocket technology. The first Soviet ICBM, the SS-6/R-7, was built to carry the heavy Soviet nuclear warhead. However, its most significant flight occurred on 4 October 1957, when it launched the first human-made satellite, Sputnik I, into Earth orbit. As euphoria overtook the Soviet Union, the American public reeled in shock. If the Soviets were capable of launching a satellite to fly over American soil, were they not also capable of launching a nuclear weapon to the United States? And why hadn’t the United States launched a successful satellite first? Nikita Khrushchev (1894–1971), who succeeded Stalin as Soviet premier in 1958, recognized the symbolic importance of Sputnik. The worldwide perception was that the USSR had overtaken the United States in science and technology; this implied military superiority.

As Americans panicked, President Dwight D. Eisenhower (1890–1969) remained secure in his knowledge of America’s military superiority in the areas of intermediate-range missiles, miniaturized nuclear weapons, bases near the Soviet Union, and spy planes. Just a year after Sputnik, von Braun’s Army rocket team managed to launch the first American satellite, Explorer 1, with a modified Redstone rocket, the Jupiter-C. On 1 October 1958, Eisenhower announced the creation of the National Aeronautics and Space Administration (NASA), which would be based on the modest National Advisory Committee for Aeronautics (NACA). Although the military branches wished to carve out a place for themselves in the arena of spaceflight, they would not hold responsibility for the high-profile manned space programs of the 1960s.

NASA’s first mission, now that the Soviets had beat it into space, was to put a man in space first. NASA called the program Project Mercury. On 9 April 1959, NASA administrator T. Keith Glennan announced the names of the first seven American astronauts who would fly in Project Mercury. The American media and public went into a frenzy over the “Mercury 7,” one of whom they believed would be the first man in history to orbit the Earth. Americans viewed the photogenic military test pilots as space warriors who, through their bravery, would save the United States from the spreading “red tide” of communism. In the USSR, however, Khrushchev and Sergei Korolev, the Soviet space program’s chief designer, had likewise determined that a Russian should be the first man into space. Indeed, the Soviets won this particular race as well. On 12 April 1961, the cosmonaut Yuri Gagarin, in a Vostok spacecraft atop a new A-1 rocket, was launched into Earth orbit. The United States reacted strongly to the news, and NASA administrators and engineers accelerated the pace of Project Mercury.

The first American astronaut was Alan B. Shepard Jr. His fifteen-minute suborbital flight, launched on 5 May 1961, by the von Braun-designed Army Redstone rocket, did not match the Soviet achievement but it did put America back into the space race. However, the Redstone launcher, with a thrust of 75,000 pounds, did not have the power to place a manned spacecraft into the Earth’s orbit. For this objective, NASA used the U.S. Air Force’s Atlas ICBM, with a total thrust of 360,000 pounds.

Astronaut Buzz Aldrin stands on the moon near the lunar module facing the American flag in 1969. National Aeronautics and Space Administration.

Following on the heels of Shepard’s flight, President John F. Kennedy (1917–1963) made a dramatic announcement to Congress on 25 May 1961. He called for the achievement of landing a man on the moon and returning him safely to the Earth before the end of the decade. Kennedy’s announcement accelerated the space race because it gave an increased sense of national importance and urgency to NASA. The agency continued with Project Mercury, but it accelerated development of its lunar landing program, Project Apollo. In December of 1961, NASA announced Project Gemini, which would place two men into Earth orbit for extended periods. Gemini would practice many of the techniques used on Apollo, including the rendezvous of two spacecraft, the docking of two spacecraft, and spacewalking.

NASA successfully launched astronaut John H. Glenn Jr. into orbit on 20 February 1962, in the Mercury spacecraft, Friendship 7. This flight required much more effort on the part of the astronaut, the flight controllers, and the spacecraft, which had to perform critical maneuvers and keep the astronaut alive for several hours. The Mercury program continued with three more flights, concluding with Gordon Cooper’s successful 22-orbit flight on 15 May 1963. Mercury had achieved its major objectives of placing a man into Earth orbit and recovering him successfully.

NASA announced Lunar Orbit Rendezvous (LOR) as the Apollo mission mode in June of 1962. With LOR, von Braun’s Saturn V rocket, with a thrust of 7,500,000 pounds, would propel a crewed spacecraft, a service module with supplies, and a lunar module toward the moon. Once in orbit around the moon, the lunar module would separate from the command and service modules, carrying two astronauts to the moon’s surface while the command module pilot stayed in lunar orbit. The lunar module itself would have two stages, an ascent stage and a descent stage. When the astronauts finished their exploration of the moon’s surface, they would return to lunar orbit in the ascent stage, leaving the descent stage on the moon, and dock with the command module. On approach to Earth, both the ascent stage and the service module would be jettisoned. Only the command module would return to Earth. Although NASA originally thought this method too risky, its weight-saving advantages and the fact that each component could be engineered independently for a particular purpose ultimately made it the most practical of the modes considered. The LOR mission mode determined nearly every aspect of Apollo development, from crew training to spacecraft design to spacecraft maneuvering systems.

Mercury astronaut Gus Grissom and “New Nine” astronaut John Young piloted the first flight of Project Gemini, on 23 March 1965. The Gemini spacecraft, while based on the Mercury spacecraft, was larger and had a number of more sophisticated systems to allow performance in maneuvering, rendezvous, and docking. Later Gemini flights would dock with the Agena target vehicle, which was really the hollowed-out upper stage of an Atlas rocket fitted with docking adapters. But on 18 March 1965, Korolev dealt the United States another blow when Aleksei Leonov made the first spacewalk, lasting twelve minutes and nine seconds. Leonov and fellow cosmonaut Pavel Belyayev orbited the Earth in Voshkod 2, an updated version of Gagarin’s Vostok spacecraft. Edward H. White III of Gemini IV performed the first American spacewalk on 3 June 1965. However, from this point on, American performance in manned spaceflight would consistently outstrip Soviet performance up to the lunar landings.

Between March 1965 and November 1966, ten Gemini flights took place. While the United States set one space record after another, no cosmonauts orbited the Earth. In October of 1965, Gemini VI rendezvoused with Gemini VII, with the crew of Gemini VII spending two weeks in Earth orbit. The first successful docking of two spacecraft occurred during Gemini VIII, which was crewed by Neil Armstrong and David Scott. The final flight of the program, Gemini XII, solved many problems inherent to spacewalking and helped to refine flying techniques as well as spacesuit technology. With the conclusion of Project Gemini, spaceflight had become operational if not routine, and many of the skills needed for Apollo had been honed to sharp accuracy.

Although Project Gemini had seen some close calls in space, NASA’s first major catastrophe occurred on the ground. On 27 January 1967, during a routine ground test at the Kennedy Space Center, the Apollo One command module burst into flames and the three crew members, Gus Grissom, Ed White, and Roger Chaffee, perished through asphyxiation. Investigations showed that while faulty wiring was the immediate cause of the fire, neither NASA nor the contractor North American Aviation had fully understood the need for all components to work together in a complex system. Many at NASA and at North American Aviation believed that the fire gave them a new awareness of possible problems and actually facilitated the success of Apollo. The tragedy shook public confidence in Apollo, but, inspired by the memory of John F. Kennedy, Americans continued to support the program.

Space shuttle liftoff from the Kennedy Space Center, Merritt Island, Florida. State Library and Archives of Florida.

With many changes now built into the Apollo spacecraft, Apollo 7, a test of the command and service module in Earth orbit was launched on 11 October 1968. Apollo 8, launched on a Saturn V on 21 December of the same year, successfully circumnavigated the moon with the command and service modules, albeit after the USSR had managed to orbit the moon with an unmanned spacecraft, Zond 5. Satellite photos revealed that the Soviet moon rocket, the N-1, might soon be ready to take men to the moon. Project Apollo culminated in the Apollo 11 mission, launched on 16 July 1969, with commander Neil Armstrong, lunar module pilot Buzz Aldrin, and command module pilot Michael Collins. Two weeks before the launch, a Soviet N-1 moon rocket blew up on its launch pad, effectively ending the moon race. Armstrong and Aldrin touched down on the moon on 20 July1969, with a television audience of approximately a billion people. Backed by many thousands of workers, managers, and engineering specialists, Armstrong, Aldrin, and Collins met Kennedy’s goal and fulfilled the age-old dream.

With Apollo now fully operational, the focus of the program shifted to scientific lunar exploration. With the exception of Apollo 13, subsequent missions made significant discoveries regarding the geological composition and history of the moon using new equipment, such as the lunar rover. The final Apollo mission, Apollo 17, splashed down on 19 December 1972. The crew had taken the first photograph of the full Earth from space, underscoring the planet’s fragility and interconnectedness.

In retrospect, it is not surprising that the Americans reached the moon before the Soviets, despite early Soviet success. The death of Sergei Korolev in 1966 sealed the fate of a Soviet moon program that was under funded and subject to corruption, with resources spread too thinly over many design bureaus. The result was less equipment, fewer tests, and weaker technology. The American space program had the benefit of a thriving economy, largely due to its position after World War II, which was much stronger than that of the Soviet Union. Government and private enterprise formed strong partnerships in the United States that benefited the space program through NASA’s practice of awarding contracts to aerospace companies who would then build space hardware. Ironically, the democratic-capitalist United States government had better command of its space resources than the totalitarian USSR.

Mars exploration has been prominent in the space programs of the Soviet Union (and later Russia), the United States, Europe, and Japan, with numerous missions and robotic spacecraft having been launched toward or directly at Mars since the 1960s. Mercury has been visited by the Mariner 10 and MESSENGER missions, the former in 1975, while the latter made a flyby in January 2008. A third mission is due to arrive in 2020. Similar to Mars, Venus has had many missions sent to it; the first was the American Mariner 2 craft in 1962, but most have been from Soviet Venera craft. Exploration of Jupiter has been undertaken since 1973 by a series of NASA’s automated spacecraft, most of them, apart form the orbiting Galileo craft, have been flybys. Saturn too has been explored only through unmanned NASA visits, including flybys by Pioneer 11 (1979), Voyager 1 (1980), Voyager 2 (1982), and the Cassini mission which entered orbit in 2004 and is likely to run into 2010. Uranus has only been explored through Voyager 2, with the closest approach coming in January 1986. Similarly, the sole visit to Neptune was the flyby of Voyager 2 in 1989.

With the winning of the space race and the advent of détente, America’s political will to support large-scale space initiatives dissolved. The Skylab temporary space station project of the 1970s utilized leftover Saturn V rockets and increased knowledge of living and working in space. The Apollo-Soyuz test project of 1975, in which Apollo and Soviet Soyuz spacecraft rendezvoused and docked in the Earth’s orbit, marked the first major cooperative venture in space.

During the late 1970s, NASA completed the development of the space shuttle program. Originally intended to serve as a taxi with routine flights to and from a permanent orbital space station, the shuttle instead stood on its own because of NASA’s reduced budget. A private company built the shuttle fleet, which had its maiden voyage with the shuttle Columbia launching on 12 April 1981. During nearly three decades in service, space shuttles have deployed military satellites, housed numerous science experiments, carried the Hubble space telescope into space, and helped build the International Space Station (ISS). Yet the two major disasters of the Shuttle program, the Challenger explosion on 28 January 1986, and the disintegration of Columbia during reentry on 1 February 2003, underscored the problems of constant, routine access to space that had plagued the shuttle program since its inception. In both cases, experts blamed the nature of NASA bureaucracy, which had become increasingly inflexible since the days of Apollo.

The Soviet policy of glasnost (openness) initiated under Premier Mikhail Gorbachev (b. 1931) meant that the successes and failures of the Soviet space program could be discussed openly. This policy certainly helped the success of the Mir space station (1986–2001), the world’s first long-term orbital structure for living and working in space. Assembled with updated versions of the Soyuz spacecraft, the station proved the feasibility of long-term space habitation, hosting several American crews during its tenure. The fall of the USSR in 1989, although difficult on the Russian program, opened up new commercial opportunities for spaceflight in Russia.

Since the end of the superpower space race, many other nations have begun to participate in the arena of space exploration. Major European nations joined the European Space Agency in 1980. The agency has contributed key satellites and scientific instruments to Russian, American, and joint endeavors. Additionally, the agency has produced many launchers for commercial use. Groups in Japan, including the National Space Development Agency (NASDA) have also begun to make strides into space with sophisticated technology. The Chinese space program, while younger than and not as versatile as the European and Japanese programs did succeed in putting a man into space on 15 October 2003.

The construction of the International Space Station (ISS) began in 1994. Although NASA has overall responsibility for the project, major components have been built by Russia, ESA, and NASDA. The station has been widely criticized for cost overruns and delays that have consumed much of the NASA budget. However, the station has hosted important research, particularly in the area of pharmaceuticals, and has provided humans with a permanent place to live and work in space.

Two major themes currently dominate much of the discourse surrounding space exploration: the possibility of a manned mission to Mars and the widespread privatization and democratization of space travel. For years space enthusiasts of many stripes have been lobbying for a manned mission to Mars. However, without major political impetus, such as the need to upstage the Russians in the Cold War, American leaders have seen little reason to fund such an expedition, and countries other than the United States do not have the resources for such a mission in the near future. President George W. Bush (b. 1946, in office 2001–2009) announced plans for a permanent lunar base with a Mars landing in the next twenty years, but even with careful budgeting, this will be difficult to complete without a strong national commitment. In 2010, at the beginning of the second year of President Barak Obama’s administration, rumors that U.S. plans for future human spaceflights would abandoned were met with harsh criticisms (especially from NASA) until he renewed the goals, which included a Mars landing by 2030.

The flight of the first privately funded spacecraft, SpaceShipOne, designed by the U.S. aerospace engineer Burt Rutan (b. 1943), on 21 June 2004, inspired many entrepreneurs who wish to expand the opportunities for human spaceflight. Using SpaceShipTwo, a reusable sub-orbital spaceplane, Virgin Galactic aims to be taking tourists into space by 2010. Other privateers include Bigelow Aerospace, which has launched two space station modules—Genesis I and II—and plans to build an orbiting hotel in space. SpaceX’s Falcon 1, a liquid-propelled orbital launch vehicle has undertaken two successful flights; Falcon 9 is scheduled to launch in May 2010. To a certain extent the Google Lunar X-Prize has served to hasten private space exploration through the announcement of a $20 million prize for the first privately funded mission to the moon. But so has the general desire for space exploration and the need to be the first.

Existing space technology is extremely expensive and space travel is dangerous. These factors currently inhibit space exploration from being immediately profitable and accessible to all. Yet, if you have enough money the Russian space program has been willing to take paying passengers into space. But if dedicated scientists and engineers continue to pursue solutions to the problems of propulsion, spacecraft control, and long-term human survival in space, the possibility of space exploration for all—both in the Earth’s orbit and in interplanetary space—will come closer to our grasp.