Since space exploration first began on October
4, 1957, spacecrafts have explored every type of object in the Solar System and in outer
space. On that day, the USSR launched Sputnik 1, the first artificial satellite
to orbit the Earth. The first space flight with humans aboard was made on April
12, 1961 when a Soviet cosmonaut circled the Earth in a spacecraft. We
always dreamed of travelling in space, and wanted to explore the unknown to
answer many questions about the Universe, such as, how the stars, the Sun, and the
planets were made, and whether life exists elsewhere. Scientists thought it
was impossible to reach the Moon until the Apollo 8 spacecraft orbited the Moon 10 times in
1968. During the fifty years since the first space expeditions were made,
spaceships have travelled around the Solar System visiting all kinds of
Mariner 10 was the first spacecraft to use gravity in space. Mariner 10 was being flung by other planets' gravity. Explorer 1 was the first spacecraft launched by the U.S, and was also the first spacecraft developed, built and launched in less then three months. Malligon was the first spacecraft launched by a space shuttle, and also orbited Venus. Voyager 1 completed its Jupiter encounter in early April after taking almost 19,000 pictures and many other scientific measurements. Voyager 2 continued in late April and its encounter continued into August. They took more than 33,000 pictures of Jupiter and its five major satellites or moons. The Saturn V was the first spacecraft that encountered 2 planets. The Saturn V orbited around the Sun in the opposite direction from the Earth's orbit, and was also the last spacecraft to see the inner planets in our Solar System.
The Sun is the most important star in our Solar System. People dreamed of space flight for thousands of years before it became reality. Evidence of the dream exists in myth and fiction as far back as Babylon in texts of 4,000 BC. In the seventh and sixth centuries BC, the Greek philosophers Thales and Pythagoras noted that the Earth is a sphere, and that it moves around the Sun. Hipparches, another Greek prepared information about stars and the motions of the Moon in the second century BC.
Bibliography and Additional Sources of Information