There are literally hundreds of satellites that are currently orbiting
Earth, including the International Space Station. Clearly, satellites are important in our lives — helping us communicate with one another, tracking weather conditions, broadcasting live sports, and so on.
Moreover, satellites help illustrate many principles tied to orbiting and gravity. As such, it is important to track the positions of satellites as they circle our planet. In this activity, students will access an online directory and tracking database of satellites, plot the locations of satellites and track their progress in orbit.
In the course of completing this lesson, students should:
• Distinguish different types of satellites
• Track orbital paths of satellites
• Identify various benefits of satellites
Space Science
Physical Science
60 – 90 minutes
Gravity is the force that keeps planets in orbit around the sun and governs the rest of the motion in the solar system. Gravity alone holds us to the Earth’s surface and explains the phenomena of the tides.

There are several thousand pieces of man-made space debris (aka space “junk”) orbiting the Earth. Many of these pieces are leftover parts from rockets used long ago. A large number of them are satellites that are currently used to:
• Map the surface of the earth
• Take pictures of storm systems that help meteorologists predict the weather
• Record temperatures of the ocean waters
• Improve telecommunications for television, phone and computer usage
• Take pictures of planets, stars and galaxies far, far away
• Assist with national security
• Computer with Internet access
• World map
There are four basic types of satellite orbits but each satellite can follow only one orbital path.. The four types are:
• Polar orbiting satellites - These satellites orbit from the
North Pole to the South Pole and back to the North Pole, over and over again. As the Earth spins beneath the satellite, the satellite takes pictures of a narrow path of the Earth underneath it.
• Equatorial orbiting satellites - These satellites orbit around the equator. Their orbits don’t follow the equator exactly — rising
“above” it, dipping “below” it then back again.
• Inclined orbiting satellites - These satellites orbit at an angle as they go around the Earth.
• Geostationary orbiting satellites - These satellites sit high above the Earth (about 35,000 km) and stay above the same place all of the time.
The ISS is an inclined orbiting satellite, maintaining a low Earth orbit in a nearly circular path of 51.6 degrees. Its minimum mean altitude is 330 km (205 miles) and its maximum mean altitude is 410 km
(255 miles). As a manned satellite (human occupied or human tended), the ISS is a great example for examining the principles and effects of gravity and orbits. Moreover, its orbital position is influenced by the need to dock periodically with spacecraft from Earth.
Go to ISS Tracker, www.isstracker.com, to see a picture of the ISS orbit tracks in both Northern and Southern Hemispheres. The tracks appear to be “wavy” as a result of the Earth’s rotation and the fact that the ISS is an inclined orbiting satellite.

1. Prompt students to think about and then write down the following (individually, in pairs, or small groups).
• What is a satellite?
• What are some examples of satellites?
• Is the International Space Station a satellite? (Why or why not?)
• How far above the Earth do you think satellites typically orbit?
2. Have students go to the glossary on the CASIS Academy microsite [www.casisademy.org] and adjust their answers if need be. Helpful terms within the glossary include: satellite [multimedia], orbit [multimedia], International Space Station [multimedia], space station, and thermosphere
[multimedia].
3. As a class, discuss what students thought about satellites prior to exploring the glossary that was confirmed and/or refined as a result of their investigations on casisacademy.org. As part of the discussion, ask students if they learned how often the ISS orbits the Earth (nearly 16 times, 15.7 to be exact) and then ask how long it takes the ISS to orbit the Earth (approximately 90 minutes). End the short discussion by asking students if they think satellites ever collide, and if not, how that is possible (which helps set up the remaining steps).
4. As a class, go to the website, http://www.fourmilab.ch/Earthview/satellite.html. At this website, there is a window containing the names of over two dozen satellites that are currently orbiting the Earth.
On the right side of this widow, scroll down the list to see dozens of different satellites.
5. In pairs or small groups, have students make the table below on a piece of paper. Then select one of the satellites and record its name.

6. Next, students should click on the button at the bottom of this window that says View Earth From
Satellite. This page shows what the satellite is currently “seeing.” If the picture is black, that’s because the satellite is on the night side of the Earth. Along with the picture, the distance that the satellite is currently orbiting above the Earth is given, as well as the latitude and longitude of the satellite. (See if students notice that the latitude and longitude are given in degrees and minutes.)
Have students write down the satellite’s position or location.
7. As a class briefly discusses latitude and longitude and its use of degrees and minutes to plot locations on Earth.
8. Using the world map, have students plot the latitude and longitude of the satellite they selected.
9. After they have selected and plotted one satellite, students should select 3 – 5 more satellites, recording their name, altitude, and location. They should use a different colored pen and/or a symbol for each one.
10. After recording the information for each satellite, students should then research each one, determining:
• Type of satellite (purpose)
• Years in orbit
• An interesting fact/characteristic
11. Have students recheck the coordinates of each satellite every five minutes and plot the new positions on the world map, determining the orbital path that each satellite seems to be taking. (Have students extrapolate from the coordinates.)
12. After 25 – 30 minutes, have students share some information about their satellites, with particular emphasis on their orbital paths.

• Satellites are vital to many aspects of our economy, and each one is a huge investment to build and to launch into orbit. Have students research a specific satellite or type of satellite and complete a basic cost-benefit analysis (CBA) on it. The CBA should calculate the costs for developing and launching the satellite and then list all of the economic benefits for having the satellite operational. If it is hard to find information on the economic impact of the benefits, have students create a 1 – 5 scale (such as 5 = huge economic impact; 1 = minor economic impact) for each benefit.
• A good alternative site is: http://science.nasa.gov/realtime/jtrack/3d/JTrack3D.html. This site is a little more graphic and may be more enjoyable to the users. Please note that this site requires a JAVA plugin that may need loading on your computers/tablets.
• Another activity once the satellite paths are charted is to determine the velocity of the satellite(s).
This activity incorporates the use of map scales and dimensional analysis. Using a ruler, measure the distance between two plotted points and convert that distance to miles (or km). Divide this distance by the time (five minutes if readings are being taken every five minutes) and convert to miles per hour (or km per hour).
• To build off the View Earth from Satellite feature, have students write from the perspective of the satellite, incorporating what it “sees” and what its functions are. Additionally, to add a historic perspective, challenge students to imagine what the satellite would have seen in a different time period and write about it.
• To abridge this lesson, plot one satellite together as a class and assign each group one satellite to plot and monitor.
• To extend this lesson as a class and/or for students who are really interested in satellites, investigate
EarthKam [https://earthkam.ucsd.edu]. It is an educational outreach program allowing middle school students to capture images of our Earth from a digital camera on board the International Space
Station. It can help students apply their knowledge of tracking satellites.
Adapted from #1616. Tracking Satellites Using Latitude and Longitude, by Rick Dees http://teachers.net/lessons/posts/1616.html