Thematic Organizer

Satellites have played a role in many areas of our lives during the past 40 years. Have you heard of Sputnik? Russia launched the first mand-made satellite - a 1 meter diameter object that sent out an electronic signal as it orbitied the earth. It didn't matter that it was not capable of any useful task, what mattered was that it demonstrated that objects could be placed the space above your head and that those objects might be able to cause the destruction of the ground below them. Sputnik caused the United States to launch a major effort to design and build a rocket capable of sending a person to the moon. As you know, we did exactly that and by 1969 walked on the moon. Ever hear of James Bond's Goldeneye - a fictional weapon of destruction. Satellites also appear as the living quarters for space-based thrillers.

In real life, satellites usual make the news for one of two reasons. Either a spectacular failure - such as when Galaxy 4 in 1998 lost its orientation with the earth and celluar phone and beeper traffic was disrupted for a 24 hour time period. You might look at http://www.stk.com for more information on this incident. The other way satellites break into the news is when they acquire fantastic pictures of the universe, such as those produced by the Hubble Space Telescope. Many of the pictures are hosted at http://www.stsci.edu/ or http://antwrp.gsfc.nasa.gov/apod/astropix.html.

Other satellites are used to orbit planets besides the earth, such as the MOLA (Mars Orbiting Laser Altimeter) satellite which is collecting data to produce a detailed topographic map of the martian surface. Studying Mars is interesting because it appears that Mars had a reasonable amount of water on its surface at one time. We would like to know where this water went - after all we would not want a similar phenomena to occur on the earth. More infomration about the MOLA project can be found at http://ltpwww.gsfc.nasa.gov/eib/mola2_about.html.

You might already have a "cell phone" or beeper in your possesion. Have you ever stopped to consider the technology behind these devices? You've probably heard of celluar towers - antennae which connect "cells" or regions together in a broad network for communication purposes. These towers have a range which is based upon the topography of the area as well as the power with which the celluar phones broadcast. As the number of celluar phone users increased so did the demand for increased coverage areas. This necessitated another look at erecting thousands of celluar phone towers around the country. As you answer the questions below, please record your answer in your Electronic Notebook.

What is a cell?

What is the basic concept behind celluar phones?

Why use satellites for communications?

What are the advantages / disadvantages of using satellites for communication?

As you proceed with your case investigation relate what you know to this topic about Satellites in Communication Systems. Think about research questions you would like to answer. What are some preliminary ideas that come to mind now? Use the Electronic Notebook to record your present thoughts.

Directions: Read the statements below. Then read the information that follows about using Satellites in communications systems. If you agree with the statement place a check mark on the space provided. If you disagree with the statement leave it blank. Be able to give reasons to support whether or not you checked each statement.

Upon completion, discuss your responses to these statements with your teacher and/or other students who are interested in investigating aspects of this case. After your discussion, review your Research Questions that you entered in the Electronic Notebook earlier. Have you narrowed your case investigation with this topic? If so, do you need to restate your Research Questions?

_____ 1. The use of satellites as communications relay stations is a relevant topic for investigation.

_____ 2. Satellites pose major disadvantages in the design of celluar systems.

_____ 3. Satellite useage offers major advantages for celluar phone service.

_____4. The topography of an area can be ignored when using satellites, but not when using celluar phone towers.

_____5. The altitude at which satellites orbit the earth is unrelated to the design of the celluar phones.

_____6. The altitude at which satellites orbit the earth is related to the number of satellites required to cover an area or region.