Download The Solar System: The History of Space Exploration

SOL 6.8 / Earth/Space Systems Part 7
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The Solar System: The History of Space Exploration
With the development of new technologies over the last half-century, our knowledge of the
solar system has increased substantially. Let’s investigate these advancements in solar
system exploration.
The father of modern rocketry was an American physicist by the name of Robert Goddard.
During the early 1900s, he built and tested many early rocket engines. By World War II,
the U.S. military began to look seriously at his work. Near the end of the war, 127 German
rocket scientists surrendered to U.S. troops. Their expert skills, along with the
development of long-range and intercontinental ballistic missiles, resulted in machines that
could break out of Earth’s gravitational pull and travel into the solar system and beyond.
Rocket research would explode in the 1950s.
In the fall of 1957, the Soviet Union launched Sputnik I, an artificial, unmanned satellite
into orbit around the Earth. Within a month, Sputnik 2 with its passenger, Laika the dog,
was successfully launched. Americans became concerned by these incredible advances in
Soviet space research.
As a result, in 1958, the National Aeronautics Space
Administration or NASA was created. Under its direction, U.S. rocket development teams
joined forces to build and test rockets. By January 31, 1958, the first U.S. satellite,
Explorer 1, was launched. The space race had officially begun!
From the 1940s to the 1980s, the Cold War raged between the Soviet Union and the United
States. During this time, both nations built up their military forces and developed satellites
to keep an eye on each other. These early satellites were used to take pictures and monitor
what the other side was up to. In addition to military satellites, the U.S. began launching
weather and communications satellites by the early 1960s.
The Space race did not stop with the development of satellites. In 1958, orbital missions
such as The Mercury Project were begun by the United States. This was the first U.S.
man-in-space program. Its goal was to place a manned space craft in orbital flight around
the Earth. Six manned flights were accomplished. In 1962, the manned flight program
was extended with the development of The Gemini Program and ten additional manned
missions were completed.
© 2006
SOL 6.8 / Earth/Space Systems Part 7
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The Solar System: The History of Space Exploration
(continued)
Between 1969 and 1972, the United States set its sights on missions to the moon with
Project Apollo. On July 20, 1969, the Apollo 11 landing module, Eagle, landed on the
moon. Astronaut Neil Armstrong became the first human to walk on the lunar surface.
Project Apollo eventually placed twelve humans on the moon’s surface. The Apollo
astronauts set up experiments and brought back samples of lunar rocks.
In addition to satellites and human space flight, scientists were also interested in what lay
beyond Earth’s orbit. By the late 1950s, space probes began to leave Earth’s gravitational
hold and venture into other parts of the solar system. Space probes are machines that can
be sent into deep space to visit planets, study asteroids, and collect data. In 1975, the
United States sent a pair of space probes, Viking 1 and Viking 2 to search for life on the
surface of Mars. Although no evidence of life was found, scientists began to ask more
questions about the “red” planet. In 1996, the U.S. sent another probe to Mars. This probe
was called Mars Pathfinder and it released a rover called Sojourner to further study the
Martian surface.
In addition to the Mars missions, the United States also sent probes to visit the solar
system’s outer planets. In the 1970s, Pioneer probes studied Jupiter and were the first to
venture past the orbit of Pluto. By the late 1970s, Voyager probes were launched and were
the first to pass by the gas giants of the solar system. In 1989, the Galileo probe was sent to
study Jupiter and its moons.
As the astronomical costs of the space program continued to grow, proposals were soon
made for the production of a reusable space transportation system. As a result, the
space shuttle Columbia was launched in 1981. It was one of the most complex machines
ever built and would take off like a rocket, orbit the Earth like a spaceship, and land on a
runway like an airplane. Shuttles soon began to carry satellites, scientists, and experiments
into orbit.
In addition to satellites, probes, and manned space flights, the United States and the Soviet
Union were interested in placing manned space stations in low orbit around the Earth.
Early space stations included the Russian Salyut 1 in 1971 and the U.S. Skylab in 1973. In
1986 the Soviet space station Mir allowed Soviet cosmonauts and American astronauts to
work together in space. The Mir, which orbited from 1987 until 1999 opened the way for
the next generation of space stations and a new era in space exploration. The completion
of the International Space Station and the arrival of its first crew in October of 2000 was
the result of contributions from sixteen countries and over 100,000 people. This
monumental project will hopefully further our space technologies and discoveries while
promoting cooperation among the nations of the world.
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