Rockets and Space Exploration

1. Rockets and Space Exploration

2. Traveling into Space • Rocket – a device that expels gas in one direction to move in the opposite direction. • The first rockets were made in China in the 1100s • Modern rockets were first developed in the early 1900s by Russian and American physicists. • Rocket design made major advances during World War II, when Germans used a rocket called the V2 to destroy both civilian and military targers.

3. How do Rockets Work? • A rocket moves forward when gases shooting out the back of the rocket push it in the opposite direction. • Action and Reaction Forces • Basic physics law: For every force or action, there is an equal and opposite force or reaction. • Thrust – the reaction force that propels a rocket forward. Amount of thrust depends on mass and speed of gases propelled out of the rocket. • Greater thrust, greater velocity. • Velocity – the speed in any given direction.

4. Orbital and Escape Velocity • Orbital Velocity – the velocity a rocket must achieve to establish an orbit around Earth. • If a rocket moves slower than orbital velocity, Earth’s gravity will cause it to fall back to the surface. • Escape Velocity – the velocity a rocket must reach to fly beyond a planet’s gravitational pull • A rocket with a velocity of 40,200 km/hr or more can escape Earth’s gravity and fly off into space.

5. Multistage Rockets • The main advantage of a multistage rocket is that the total weight of the rocket is greatly reduced as the rocket rises. • Smaller rockets, or stages, are placed one on top of the other and fired in succession. • In the 1960s, multistage rockets, such as the Saturn V made it possible to send spacecraft to the moon and the solar system beyond. • Today, multistage rockets are used to launch a variety of satellites and space probes.

6. The Race for Space • In the 1950s, the U.S. and the Soviet Union (Russia) began to compete in space exploration, called the “space race”. • At the time, the Soviet Union was the greatest rival to the U.S. in politics and military power – Cold War. • In 1957, the Soviets launched a satellite, Sputnik I, into orbit.

7. First Artificial Satellite • Satellite – an object that revolves around another object in space. • The moon is a natural satellite of Earth. • A space craft orbiting Earth is an artificial satellite. Sputnik I is an example of this. • Soviet success in satellite launching caused alarm for the U.S. • U.S. responded in 1958, launching the Explorer I into orbit. • Late 1958 – U.S. created National Aeronautics and Space Administration (NASA), a government agency in charge of space program.

8. Humans in Space • 1961 – space race heated up! • Soviets launched the first human into space. Yuri Gagarin flew one orbit around Earth aboard Vostok 1. • Less than one month later, Alan Shepard became the first American in space aboard Freedom 7. • First American to orbit Earth – John Glenn in 1962, aboard Friendship 7. • Spacecraft he traveled in was called a space capsule because it was like a small cap on the end of the rocket. The capsule orbited Earth three times.

9. Missions to the Moon • May 1961 – President John F. Kennedy launched an enormous program of space exploration & scientific research • Apollo program was the American effort to land astronauts on the moon. • Unpiloted U.S. spacecraft Surveyor landed on the moon and did not sink, proving the moon had a solid surface.

10. The Moon Landings • July 1969 – 3 American astronauts aboard Apollo 11 circled the moon. • Buzz Aldrin & Neil Armstrong entered the tiny spacecraft, Eagle, and on July 20 landed on the Sea of Tranquility, a flat area on the moon’s surface.

11. Exploring Space Today • Space Shuttles – spacecrafts that an carry a crew into space, return to Earth, and then be reused for the same purpose. • Before 1983, spacecraft could only be used once. • NASA has used space shuttles to perform many important tasks, such as: taking satellites into orbit, repairing damaged satellites, and carrying astronauts to and from space stations.

12. Space Stations • Space Station – a large artificial satellite on which people can live and work for long periods. • A space station provides a place where long-term observations and experiments can be carried out in space. • In the 1970s and 1980s, both the U.S. and Soviet Union placed space stations in orbit. • In the 1980s, the U.S. and 15 other countries began planning the construction of the International Space Station. • In 1998 – first section placed into orbit. Since then, many other modules have been added on.

13. Space Probes • Space Probe – a spacecraft that carries scientific instruments that can collect data, but has no human crew • Space probes gather data about distant parts of the solar system where humans cannot easily travel. • Each probe is designed for a specific mission. • Some probes are designed to land on certain planets • Some probes are designed to fly by and collect data • Each probe has a power system to produce electricity, a communication system to send and receive signals, and scientific instruments to collect data or perform experiments.

14. Space Probes, cont’d The scientific instruments that a probe contains depend on the probe’s mission. Some are equipped to photograph and analyze the atmosphere of a planet. • Others are equipped to land on a planet and analyze the materials on its surface. • Some probes have small robots called rovers that move around on the surface • A rover typically has instruments that collect and analyze soil and rock samples.