Space Exploration and Travel [antikvár]

Human beings have always looked to the skies and dreamed of traveling into space. But until the middle of the twentieth century, space travel remained no more than a dream. Then, on October 4, 1957, Sputnik 1, a Russian satellite, was successfully launched. The Space Age had begun.Since that day, many spacecraftwith and without human occupantshave been sent beyond the Earth's atmosphere. Astronauts have walked on the moon; they have lived in space for weeks at a time; they have linked, or joined, two spacecraft far out in space.7Astronauts also have piloted reusable spaceships and landed them back on Earth, like ordinary jet planes. Space probes without crews have been sent into the far reaches of our solar system to gather information about the most distant planets. Every year brings new advances into the uncharted frontier of the universe.The first major step in scientific knowledge needed for space travel was made by Johannes Kepler, a German scientist. In the early seventeenth century, Kepler worked out the laws of planetary motion. These laws described the way the planets and their natural satellites, called moons, travel through space.