The Earth is the third planet from the Sun. Its diameter is 12,760 km. Means distance from the Sun is 150 millions of kilometers. The only natural satellite is the Moon.    The space age began on October 4, 1957. On that day, the Union of Soviet Socialist Republics launched Sputnik 1, the first artificial satellite to circle the earth. Its capsule weighing 83.6 kg went into Earth orbit carrying a radio transmitter whose “bleeps” (pips) were received on the ground.The first manned moon landing on the Moon was the United States' Apollo 11 mission with Neil Armstrong and Edwin Aldrin.

Armstrong landed the lunar module ‘Eagle’ on the surface of the Moon at 4:17:42 p.m. July 20, 1969. He described walking on the Moon as ‘one small step for a man, one giant leap for mankind’. The Apollo-Soyuz Test Project was the first joint flight of the U.S. and Soviet space programs.  The mission took place in July 1975. For the United States of America, it was the last Apollo flight, as well as the last manned space launch until the flight of the first Space Shuttle in April 1981. The Soviet space station Mir was launched in 1986. It was designed to stay in orbit for long periods for scientific experiments to be carried out on board.