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Introduction to Space Exploration - Ancient Perspectives On Space, Enlightened Observations, Space Travel In Early Science Fiction, The Wright Stuff
earth planet air sun
Mankind will migrate into space, and will cross the airless Saharas which separate planet from planet and sun from sun.
—Winwood Reade, 1872
Humans have always been explorers. When ancient peoples stumbled upon unknown lands or seas they were compelled to explore them. They were driven by a desire to dare and conquer new frontiers and a thirst for knowledge, wealth, and prestige. These are the same motivations that drove people of the twentieth century to venture
into space.
By definition space begins at the edge of Earth's atmosphere, just beyond the protective blanket of air and heat that surrounds our planet. This blanket is thick and dense near the Earth's surface and light and wispy farther away from the planet. About sixty-two miles above Earth the atmosphere becomes quite thin. This
altitude is considered the first feathery edge of outer space.
The very idea of space exploration has a sense of mystery and excitement about it. Americans call their space explorers astronauts. Astronaut is a combination of two Greek words, astron (meaning star) and nautes (meaning sailor). Thus,
astronauts are those that sail amongst the stars. This romantic imagery adds to the allure of space travel.
The truth is that space holds many dangers to humans. Space is an inhospitable environment, devoid of air, food, or water. Everywhere it is either too hot or too cold for human life. Potentially harmful radiation flows in the form of cosmic rays from deep space and electromagnetic waves that emanate from the Sun and other
stars. Tiny bits of rock and ice hurtle around in space at high velocities, like miniature missiles.
Space is not readily accessible. It takes a tremendous amount of power and thrust to hurl something off the surface of Earth. It is a fight against the force of Earth's gravity and the heavy drag of an air-filled atmosphere.
Getting into space is not easy, and getting back to Earth safely is even tougher. Returning to Earth from space requires conquering another mighty force—friction. Any object penetrating Earth's atmosphere from space encounters layers and layers of dense air molecules. Traveling at high speed and rubbing against those molecules
produces a fiery blaze that can rip apart most objects.
It was not until the 1950s that the proper combination of skills and technology existed to overcome the obstacles of space travel. The political climate was also just right. Two rich and powerful nations (the Union of Soviet Socialist Republics and the United States) devoted their resources to besting one another in space
instead of on the battlefield. It was this spirit of competition that pushed humans off the planet and onto the Moon in 1969.
Once that race was over, space priorities changed. Today, computerized machines do most of the exploring. They investigate planets, asteroids, comets, and the Sun. Human explorers stay much closer to Earth. They visit and live aboard a space station in orbit 200 miles above the planet. On Earth people dream of longer journeys
because most of space is still an unknown sea, just waiting to be explored.
Additional Topics
Since the earliest days people have looked up at the heavens and dreamed of flying there. In ancient Greek and Roman mythology gods and goddesses rode chariots through the skies or had wings of their own. These included Eros (the god of love), Nike (the goddess of victory), Hermes (the messenger to the gods), and Apollo (god
of the arts). In Roman mythology they were called Cupid, Victoria, Mercur…
Centuries later the great Italian painter and engineer Leonardo da Vinci (1452–1519) foresaw the day that humans would fly. He wrote "There shall be wings! If the accomplishment be not for me, 'tis for some other." Leonardo made several sketches of human-powered flying machines and gliders with bird-like wings. At the time
astronomical knowledge was limited, and it was …
Science fiction is a category of literature in which an imaginative story is told that incorporates at least some scientific principles to give it a sense of believability. It is a mixture of science and imagination. The term "science fiction" is generally credited to writer Hugo Gernsback (1884–1967), who published a magazine
devoted to such stories and started book clubs for…
On December 17, 1903, brothers Orville and Wilbur Wright made history at Kitty Hawk, North Carolina, with the first sustained flights of a powered aircraft. Each brother took two flights that day. The longest flight covered about 850 feet and lasted just under one minute. The modern age of aviation had begun. In 1905 the
Fédération Aéronautique Internationale (FAI) was formed …
When World War I began in Europe in 1914, the power of aerial warfare became apparent immediately. The United States realized that it was behind its European counterparts in aviation expertise, and in an effort to correct the situation the U.S. government formed the Advisory Committee for Aeronautics (ACA) in 1915. Later the
word "National" was tacked on, and the agency became known …
There are three men in history considered the founders of modern rocket science: Konstantin Tsiolkovsky of Russia, Hermann Oberth of Germany, and Robert Goddard of the United States. All three were working on rocket science during the early years of the twentieth century. Although they were scattered around the world, they
reached similar conclusions at about the same time. Konstantin Tsiolkovsky …
Even before World War II ended the United States began developing rocket-powered planes. In 1943 the NACA initiated the research program in conjunction with the Air Force and Navy. Because the planes were experimental, they were given the name X-aircraft. In 1944 a company called Bell Aircraft began work on the X-1. At first
it was called the XS-1, with the "S" standing for supersoni…
The term Cold War is used to describe U.S. relations with the Soviet Union from the end of World War II to the late 1980s. During this period, chiefly marked by a mutual mistrust and rivalry that led to a buildup of arms, both nations developed extensive nuclear weapons programs. Each thought the other was militarily
aggressive, deceitful, and dangerous. Each feared the other wanted to take over t…
On April 12, 1961, cosmonaut Yuri Gagarin (1934–68) became the first human ever to travel beyond Earth's atmosphere, enter the frontier of space, and return safely to Earth. Gagarin was born in a village near Gzhatsk (now Gagarin) in central Russia. He grew up in a peasant family, dreaming of becoming a pilot. Before being
recruited to be a cosmonaut, Gagarin was serving as a lieuten…
It was a month later that the first American entered space. On May 5, 1961, Alan Shepard (1923–98) soared to an altitude of 116 miles in a spaceship named Freedom 7. He spent fifteen minutes and twenty-eight seconds in a suborbital flight. Suborbital means less than one orbit. In other words, a suborbital flight does not
complete an entire circle around Earth. Shepard's flight was mu…
Suddenly all eyes were on the Moon. Earth's closest neighbor had been a subject of fascination since the first humans gazed up at the night sky. Most of the features on the Moon were named during the 1600s by an Italian astronomer named Giovanni Riccioli (1598–1671). Riccioli was a Jesuit priest, a member of the Roman Catholic
order the Society of Jesus, which is devoted to missionar…
The U.S. effort to put men on the Moon was named the Apollo program. It actually included three phases: Alan Shepard's historic flight of 1961 was considered the first Mercury mission. Over the next two years five more successful Mercury flights were conducted. In 1965 a series of ten manned Gemini missions began. They were
completed near the end of 1966. Soon after it started, it became ap…
One key goal in the United States and the Soviet Union was development of a large and powerful rocket—a so-called super booster. NASA called its superbooster a Saturn rocket. The Soviets named their rocket the N-1. Development of the Saturn rocket series began in 1961 under the direction of Wernher von Braun. He had actually
been pitching the idea to the military for several years. Before t…
The Soviet space program continued to flourish. In September 1968 an unmanned probe called Zond 5 became the first spacecraft to travel around the Moon and return to Earth. The pressure was on NASA to speed up the Apollo missions. On January 27, 1967, three American astronauts—Virgil "Gus" Grissom, Edward White, and Roger B.
Chaffee—were killed when a flash fire raced t…
NASA's space program introduced a new kind of hero to American culture—the astronaut. When the Mercury program began NASA selected seven men to be astronauts. They were called the "Mercury Seven." The men were all successful military test pilots known for their bravery and professional piloting skills: The men had to pass
strenuous batteries of physical, mental, and me…
During the early years of space flight, American relations with the Soviet Union were at their worst. Only months after the Soviets put their first cosmonauts in space the Soviet Premier Nikita Khrushchev made a veiled threat: "We placed Gagarin and Titov in space, and we can replace them with other loads that can be directed
to any place on Earth." The meaning was clear to the Ameri…
In the minds of most Americans the space race was over the day Apollo 11 set down on the Moon. Although NASA carried out six more Apollo missions, public interest and political support for them faded quickly. Neither the U.S. nor Soviet government was interested in racing to somewhere else in space. Both governments decided to
concentrate on putting manned scientific space stations in low Earth or…
The advent of the space age introduced a wealth of information to science fiction authors. They were able to produce works much more sophisticated than those of the past. One of the most innovative of these authors was Gene Roddenberry (1921–91). During the mid-1960s he created a television show called Star Trek. This was a
futuristic tale about space exploration set in the twenty-third cen…
Space programs centered on human explorers are very expensive. It is far cheaper to build and send mechanized (robotic) spacecraft to do the exploring. During the 1960s the Apollo program dominated the spotlight, but it was not the only space exploration project in operation. Beginning in 1962 NASA launched robotic probes that
flew by Mercury, Venus, or Mars and beamed back photographs of them. Du…
Application satellites are spacecraft put into Earth orbit to serve as tools of earth science or for navigation, communication, or other commercial purposes. Although they are not really space explorers, they would not be possible without the technology of the space age. On April 1, 1960, NASA launched the first successful
meteorological satellite named TIROS 1 (Television Infrared Observation Sat…
SpaceShipOne was the first privately built and financed craft to fly a human into space. For more than FIGURE 1.5 Terrestrial navigation system Joe Kunches, "Figure 1. The Paths Taken by a Radio Wave Transmitted by a Terrestrial Navigation System," in Space Environment Topics: Navigation, U.S. Department of Commerce, National
Oceanic and Atmospheric Administration, Space Environment…
The Space Age introduced new areas of commerce for the world's entrepreneurs. Companies engaged in aviation, aeronautics, and aerospace activities have been the most direct beneficiaries. However, other industries have seized upon space-based opportunities, primarily the businesses of commercial satellite services and space
tourism. In 1962 the U.S. Congress passed the Communications Satell…
Exploration has always been dangerous. Many ancient explorers died during their journeys across deserts, seas, mountains, and jungles. Space exploration has its own casualties. During the earliest days of space travel dozens of animals were sacrificed for the space program. The United States sent a variety of small animals and
primates up in rockets to test the safety of space flight for humans. …
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