StarShine

Grade Level:

Overview:

Objectives:

1. Demonstrate the conditions that must exist for a satellite to be seen from Earth.
2. Explore various ways to increase the visibility of a satellite.

Resource/Materials:

Activities/Procedures:

1. Have students brainstorm to list different types of satellites. This list should include: (This and more information can be found at http://www.howstuffworks.com/satellite4.htm )
   
   • Weather satellites - help meteorologists predict the weather or see what's happening at the moment..
   • Communications satellites - allow telephone and data conversations to be relayed through the satellite.
   • Broadcast satellites - broadcast television signals from one point to another. Similar to communications satellites.
   • Scientific satellites - perform a variety of scientific missions. The Hubble space telescope is the most famous scientific satellite, but there are many others looking at everything from sun spots to gamma rays.
   • Navigational satellites - help ships and planes navigate.
   • Rescue satellites - respond to radio distress signals
   • Earth observation satellites - observe the planet for changes in everything from temperature to forestation to ice sheet coverage.
   • Military satellites - much of the actual application information remains secret. Applications may include:
     
     • Relaying encrypted communications
     • Nuclear monitoring
     • Observing enemy movements
     • Early warning of missile launches Eavesdropping on terrestrial radio links
     • Radar imaging
     • Photography (using what are essentially large telescopes that take pictures of militarily interesting areas)
   
   Despite the significant differences between all of these different satellites, they all have several things in common. For example:
   • All of them have a metal or composite frame and body, usually known as the bus. The bus holds everything together in space and provides enough strength to survive the launch.
   • All of them have a source of power (usually solar cells) and batteries for storage. Arrays of solar cells provide power to charge rechargeable batteries.
   • All of them have an onboard computer to control and monitor the different systems.
   • All of them have a radio system and antenna so that the ground control crew can request status information from the satellite and monitor its health.
   • All of them have an attitude control system to keep the satellite pointed in the right direction.
2. Discuss with students the similarities and differences between the various types of satellites. Show them the picture of a typical satellite from Appendix 1.
3. Ask students if any of the satellites mentioned have a light source? (no)
4. Then ask students to brainstorm in groups to come up with a hypothesis as to how we can sometimes see satellites from Earth.
5. Have students use materials provided to create a model of a satellite over the Earth and demonstrate with the light source how it can be seen from Earth.
6. Upon completion, have student groups present their ideas to the class.
7. Explain to students the conditions that must exist in order to see a satellite with the naked eye. You must be in darkness and the satellite must still be in the sunlight and be able to reflect enough light to be seen. There are two times a day to look for satellites, at dusk and at dawn!
8. Explore the website: http://spacekids.hq.nasa.gov/starshine Here you will find an answer to the question, “Can satellites be seen with the unaided eye?” and you can view the animated GIF and the illustration of this phenomenon.
9. As a concluding activity, have students explain how to improve the visibility of a satellite. (Add more reflective material)
10. Individually have students research the NASA Starshine project. On June 5, 1999 NASA released a satellite called Starshine from the Space Shuttle. The satellite is essentially a big ball covered with 900 small mirrors. There are plans to release another one at the end of the year 2001.
11. See the website at: http://www.azinet.com/starshine/

Evaluation:

1. Have students explain how viewing the moon and viewing a satellite are alike and different. (They both reflect sunlight, however, the moon is much further away and much larger so it is visible from sunset to sunrise. It is only rarely eclipsed by the shadow of the Earth, satellites on the other hand are so small and so close to Earth that they are only rarely out of the Earth’s shadow)
2. Visit the site: http://www.howstuffworks.com/satellite6.htm and explore which satellites orbit at which altitudes. Have students explain, based on this knowledge, which satellites you would be able to see the longest? (the ones at the highest altitudes)