1) The document discusses concepts related to achieving and maintaining orbit around Earth such as escape velocity, elliptical orbits with apogee and perigee, and how speed and timing can adjust orbits. 2) It also describes different types of unmanned satellites that orbit Earth including communication, weather, and navigational satellites as well as their purposes and orbit types like geostationary and polar orbits. 3) Satellites have provided many benefits for exploring space and applications on Earth such as television, phone calls, storm tracking, mapping, and rescue beacon detection.

1. 8 th Grade Chapter 2 Lesson Pgs. 85-90 (Stop at Unmanned Space Probes) For Student Use Only

2. Exploring Space The Space Age: We have been given a wonderful gift of technology and material to help explore all of creation. Satellites and other spacecraft escape Earth’s atmosphere

3. Exploring Space The Space Age Achieving and Maintaining Orbit- In order for an object to orbit it must maintain a speed of about 17,200. When the object slows down it sinks towards the earth and speeds up. Then it goes higher and slows down. This causes an elliptical orbits.

4. Exploring Space The Space Age: Apogee: high point in elliptical orbit from Earth Perigee: low point in elliptical orbit from Earth As speed increases the apogee and perigee grows. Orbits can be adjusted by adjusting speed at a certain time.

5. Exploring Space Escape Velocity Escape Velocity: The speed it takes to escape Earth’s gravitational pull. Inter-Planetary: To travel from one planet to another we can use orbits (we have no way to go directly there), however it takes a long time.

6. Exploring Space Unmanned Satellites: Earth-orbiting satellites do just about everything. Astronomical Satellites: Used for research Communication Satellites: Used for TV, phone calls, etc. Communication Satellites are geostationary orbits Geostationary orbits: orbits that are directly above the equator.

7. Exploring Space Unmanned Satellites: Weather Satellites: Help show storms at sea Polar Orbit: satellites that orbit perpendicular to the equator. Rescue Satellites: receive rescue signals Navigational Satellites: tell information of lattitude, longitude, altitude and velocity from these satellites. Earth Resources Satellites: make maps, detect resources