1. Aristotle Year – 347BC believed that the Earth was at the center of the universe.

2. Ptolemy Year – 100AD He believed Earth was at the center of the universe and all other heavenly bodies revolved around it. This theory is known as the geocentric theory.

3. Nicolas Copernicus 1543 All of the planets revolve around the sun. This theory is known as the heliocentric theory.

4. Galileo Galilei In 1609, Galileo used a telescope to look at the sky. He confirmed Copernicus’ theory that the planets revolved around the sun.

5. Sputnik first artificial satellite into space on Oct.4, 1957. Launched by Soviet Union Sputnik orbited the Earth for 6 months before falling back to Earth.

6. Yuri Gagarin April 1961 First person to go into space. He orbited the Earth one time. He was from the Soviet Union(Russia).

7. Alan Shepherd May 1961 First American to go into space. Stayed in space for 15 minutes.

8. Space Race A “race” between United States and Soviet Union(Russia) to see who could go the farthest in space. "I believe this nation should commit itself to achieving the goal, before this decade is out, of landing a man on the moon and returning him safely to the Earth." He asked Congress for 22 billion dollars to finance the Apollo missions.

9. John Glenn February 20,1962 The first man to orbit the Earth in space. Orbited 3 times around Earth Landed in Atlantic Ocean

10. Rocket at launch pad Capsule in space Capsule returning to Earth Capsule lands in ocean and is recovered by a Navy ocean liner

11. Gemini Program Mid 1960s (1965) Sent 2 people into space to work on techniques for a lunar mission. “Space walks” Spent up to 14 days in space

12. Apollo 11 July 20, 1969 1 st mission to land on the moon Neil Armstrong and Buzz Aldrin 1 st to walk on the moon Michael Collins orbited the moon

13. Pictures from Apollo 11 mission

14. Space Shuttle First launch in 1981 First reusable rocket Can carry a crew of 5-8 astronauts Put satellites into orbit and/or make repairs

15. Hubble Space Telescope Put into orbit in 1990 Satellite that orbits Earth and takes pictures of other stars, galaxies, and planets

16. Mir Russian Space Station put into orbit in 1986 U.S. and Russian astronauts lived and worked in space for months at a time Came crashing back to Earth in 2001

17. International Space Station Construction started in 1998 Space station built by United States, Russia, Canada, Japan, and other countries Scientists live here and perform experiments

18. Rovers that have landed on Mars 1997 – Pathfinder lands safely on Mars and releases rover – Sojourner to study the surface. 2003 Spirit lands on Mars

19. Mariner satellites 1971 Explored inner planets – Mercury, Venus, and Mars

20. Voyager Launched from Earth in 1977 Sent to study the outer planets – Jupiter, Saturn, Uranus, Neptune Discovered Great Red Spot is a storm and Neptune has the strongest winds

21. Cassini Launched in 1997 Reached Saturn in 2004 Studying the rings and moons of Saturn