History of Humans in Space

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History of Humans in Space

Exploring seems to be a part of the human psyche. But the desire to leave the confines of Earth's gravity could not meet reality until some practical means of transportation could be developed. American physicist Robert H. Goddard's experiments in the 1920s and 1930s showed a practical way to loft objects and people into space: the liquid-fueled rocket. During World War II the German military exploited Goddard's new technology by building the V-2 rocket to carry bombs to targets in England. Larger rockets to carry nuclear bombs on intercontinental flights were developed during the Cold War. By the late 1950s, booster rockets were powerful enough to launch objects into orbit around Earth, and by 1960 they were powerful enough to carry humans with their life-support equipment. For the first time, humans had the means to leave their home planet.

Early Space Exploration

Building a vehicle to carry people into space is not something one can do in one's garage. The resources of a nation are required. The Soviet Union's very large booster rockets were the first with that capability. The Soviet Union and the United States were adversaries during the Cold War. One way for each to show off its power was to outdo the other in space achievements, which became known as the "space race." In October 1957 the Soviets launched Sputnik 1, an 83.5-kilogram (184-pound) satellite, into orbit; the following month they launched a second one weighing 500 kilograms (1,100 pounds). This capability surprised and startled the world.

In the ensuing years the Soviets launched numerous Earth satellites for communications, weather, reconnaissance , and other purposes. In preparation for a piloted spaceflight they also launched at least four spacecraft with dogs as passengers in 1960 and 1961. Then, on April 12, 1961, Yuri Gagarin became the first person to orbit Earth. The single-orbit flight in a spherical capsule named Vostok 1 lasted one hour and forty-eight minutes. On August 6 of that same year, Gherman Titov stayed in space for an entire day, making seventeen orbits.

Well behind the Soviet Union, the United States launched Project Mercury, which used a conical capsule that carried one astronaut. After several test flights carrying monkeys and a chimpanzee, Alan Shepard became the first American in space on May 5, 1961, in a fifteen-minute suborbital flight downrange into the Atlantic Ocean. Finally in February 1962 an American, John Glenn, flew into orbit and circumnavigated Earth three times in just under five hours. When Project Mercury concluded in May 1963, four Americans had flown into orbit for a total of fifty-three hours, a little more than two days. Meanwhile, Soviet cosmonauts had totaled nearly eight days.

The Race to the Moon

On May 25, 1961, only three weeks after Shepard's short suborbital flight, President John F. Kennedy committed the nation to land a man on the Moon and bring him safely home by the end of the decade. This bold commitment, made before an American had even completed one orbit, would galvanize the nation in an effort to surpass the Soviets in space achievements.

Both the United States and the Soviet Union worked to develop, perfect, and practice the necessary procedures for a lunar mission. They had to learn how to rendezvous and dock with another craft in orbit; provide life support for up to two weeks; cope with protracted weightlessness; determine the level of radiation in space that a person could endure; and a myriad of other tasks.

In the United States, Project Gemini was designed to accomplish this preliminary work. The first flight of the two-person Gemini capsule came in March 1965 carrying John Young and Gus Grissom. The Soviets continued to upstage the Americans. In October 1964, three men, a cosmonaut, a doctor, and a scientist, had been on a daylong flight in a Voshkod vehicle. In March 1965, Alexei Leonov made the first space walk while the first piloted Gemini flight was being readied on the launch pad.

Both countries sent robotic spacecraft on reconnaissance missions to the Moon during the 1960s. Some circumnavigated the Moon and photographed its surface; some landed and sent back data about the lunar surface. The Soviets sent a robotic vehicle to move over the lunar surface, and another flight brought lunar soil back to Earth.

There were eleven piloted Apollo flights. Two flew to Earth orbit only, three circumnavigated the Moon but did not land, and six landed. The first to land, Apollo 11, touched down on July 20, 1969, before the decade of the sixties was out; President Kennedy's goal for America had been achieved. Neil Armstrong and Edwin "Buzz" Aldrin were the first humans to set foot on the Moon, while Michael Collins remained in orbit around the Moon tending the return vehicle. Ten more astronauts walked on the Moon in five additional missions. Apollo 17 in December 1972 was the last.

Apollo 13 was almost a disaster. On April 13, 1970, three days out from Earth, an oxygen tank exploded in the service module of the spacecraft, disabling the Apollo command module. The three astronauts crowded into the two-person lunar lander to ride out a ninety-hour flight back to Earth. Using the lander's power system and rocket engine, the vehicle swung around the Moon and returned toward Earth. As they approached Earth, they fired the lander's engine again to put them on the proper trajectory. Then they moved back into the lifeless command module and cut it loose for a landing. The potential disaster had been avoided with no loss of life.

For many people, the ultimate goal of the world's space programs is to expand human presence into the universe beyond Earth. However, the funding to carry on these programs comes from governments, and political leaders may have other priorities. After the landings on the Moon, many hoped that sending a crew to Mars would be the next step. But more earthly issues took priority among those who controlled the purse strings. Funding for space programs declined, and the last three planned Moon flights were cancelled.

In 1975, in a gesture of international friendship, the United States and the Soviet Union joined together for a joint mission. Apollo hardware carried astronauts Thomas Stafford, Vance Brand, and Donald "Deke" Slayton to rendezvous and dock with cosmonauts Alexei Leonov and Valeri Kubasov in a Soyuz vehicle on July 17 for two days of camaraderie. They shook hands, exchanged gifts, completed five joint experiments, shared meals, and held a news conference as the world watched.

The Soviet Union never did attempt a piloted flight to the Moon. Their N-1 or SL-15 Moon rocket had forty-three engines in four stages. Engineers had trouble keeping the thrust stable in the thirty engines of the first stage and after four failures they instead turned their attention to space stations.

Space Stations and Shuttles

Salyut 1, the first space station, was in orbit from April to October 1971, and was occupied by three cosmonauts for twenty-two days in June of that year. It was about 15 meters (50 feet) long and 5 meters (17 feet) in diameter at its largest point. The Soviets had space stations in orbit almost continuously for twenty-five years from 1974 to 2000. Salyut 2 failed, but Salyuts 3 to 7 and Mir were extraordinarily successful. Mir, their last, was modular and had space for up to six cosmonauts and six ports for docking spacecraft or other modules. Cosmonauts set new records with stays in Mir of more than a year. Crew on the Salyuts and Mir observed the sky and Earth, studied the growth of weightless plants and animals, conducted science experiments, tried methods of manufacturing, and tested new types of equipment. They learned a great deal about living and working in space, the effects of weightlessness on humans, recycling air and water, designing spacecraft for extended stays, and repairing spacecraft while in orbit.

Meanwhile, the United States used leftover Apollo equipment to launch a space station called Skylab. It was launched completely equipped on a twostage Saturn V rocket. Three crews of three men each occupied Skylab for a total of 172 days in 1973 and 1974. They carried out numerous scientific experiments, photographed Earth, and studied the effects of weightlessness.

NASA then turned its attention to developing the space shuttle. The most expensive part of spaceflight is the cost of getting off the ground into low Earth orbit . Burned-out booster rockets generally drop into the ocean, and new ones are built for each flight. In an effort to find a cheaper method of access to orbit, the United States developed the space shuttle, a reusable vehicle that launches as a rocket and returns to Earth like an airplane. The booster rockets are also reusable; they are recovered from the ocean and re-conditioned for another flight. The first space shuttle flew to orbit in April 1981. One hundred missions had been flown by 2000.

On space shuttle missions, astronauts launch satellites into Earth orbits and send spacecraft to other parts of the solar system; recover inoperative satellites; repair and service the Hubble Space Telescope; carry military payloads to orbit; perform microgravity experiments; study effects of weight-lessness on the human body; test concepts for new spacecraft; and photograph Earth.

Supporting people in space is an expensive proposition. Besides food, air, and water they need a comfortable temperature, room to move around and work, and rest periods. Automatic experiments on robotic satellites require none of these. Nevertheless, if an unforeseen problem occurs, something the robotic experiment was not preprogrammed to handle, the experiment could be lost. An astronaut operating an experiment can adapt to new situations and correct unforeseen problems. The space shuttle has shown this to be true over and over again.

The Soviet Union built a vehicle named Buran that superficially looked like a space shuttle. It was launched, however, on an Energia booster rocket, whereas the space shuttle has rocket engines built into the orbiter that are brought back to Earth for another flight. Buran flew only once on an unpiloted test flight in November 1988.

The idea of a space station with participation from many countries had been considered for many years. With the end of the Cold War the idea came to fruition. The International Space Station, which was approved for development in 1984 by President Ronald Reagan, is a cooperative venture of the United States, Russia, Canada, Japan, and the eleven countries of the European Space Agency. The International Space Station dwarfs all previous space stations. Its main truss is 111 meters (365 feet) long, and in its final design configuration it would have six laboratories, two habitat modules, and two logistics modules to support up to six astronauts and cosmonauts. The modules are being carried to orbit on Russian booster rockets and in the space shuttle and are assembled in orbit. Astronauts and cosmonauts have the space and time to run long-duration experiments, to test out new concepts for space equipment, and to try to solve the problems of the human body in weightlessness. The International Space Station may also act as a base for reaching farther into the solar system.

Astronauts and Cosmonauts

Astronauts and cosmonauts are trained professionals, usually military pilots, engineers, doctors, or scientists. The first woman to orbit Earth was Valentina Tereshkova, on a three-day flight in June 1963. It was nineteen years before another woman, Svetlana Savitskaya, was to venture into space. The first American woman in space was Sally Ride, who was a crew member on a space shuttle mission in June 1983. By 1999, 384 men and women had flown into orbit: 243 from the United States, 89 from the Soviet Union and Russia, eight each from France and Germany, seven from Canada, and the rest from twenty-two other countries. More than thirty guest cosmonauts from more than two-dozen countries were flown to Soviet space stations. After the Cold War ended, American astronauts visited Mir to learn from the long experience of the Soviets and to plan for the International Space Station.

Spaceflight is a dangerous occupation. Although engineers try to consider all possible potential problems and hazards, accidents do happen and lives have been lost. In January 1967, fire broke out in the pure oxygen atmosphere of the Apollo 1 capsule during a launch rehearsal. Three astronauts died: Virgil "Gus" Grissom, Roger Chaffee, and Edward White, the first American to "walk" in space. Cosmonaut Valentin Bondarenko had perished in a similar accident in March 1961. The first person to die while actually on a spaceflight was Vladimir Komarov. The Soviets reported that on returning from orbit in April 1967 a problem with the parachute caused Komarov's Soyuz spacecraft to hit the ground at high speed. In June 1971, three cosmonauts died when the air leaked out of their Soyuz capsule during their return to Earth following a three-week stay in the Salyut 1 space station.

The space shuttle Challenger disaster in 1986 was perhaps the most devastating to the American space program. Seven astronauts perished when hot exhaust gas leaked from one of the booster rockets, destroying the vehicle less than two minutes into the flight. Shuttle flights were halted for two and a half years.

see also Apollo (volume 3); Apollo-Soyuz (volume 3); Armstrong, Neil (volume 3); Astronauts, Types of (volume 3); Challenger (volume 3); Civilians in Space (volume 3); Collins, Eileen (volume 3); Cosmonauts (volume 3); Emergencies (volume 3); Gagarin, Yuri (volume 3); Gemini (volume 3); Humans versus Robots (volume 3); Mercury Program (volume 3); Mission Specialists (volume 3); Nasa (volume 3); Payload Specialists (volume 3); Skylab (volume 3); Space Shuttle (volume 3); Space Stations, History of (volume 3); Teacher in Space Program (volume 3); Vostok (volume 3); Why Human Exploration? (volume 3); Women in Space (volume 3).

Thomas Damon