Space Projects For Mr. Kelly’s 4 th Grade

1. Space ProjectsFor Mr. Kelly’s 4th Grade Darren McKnight January 2006 NASA JSC Orbital Debris Program Office Web Site resources were used extensively in this document.

2. “Space Projects” Program Plan • Background • In each of the five project areas • Five projects to choose from • Launch satellites into orbit • Satellite design • Design a Mission to Mars • Reduce orbital debris • Reduce hazard from objects coming back to Earth For Mr. Kelly Only

3. How to Do Satellites Get Into Orbit? • Gravity is constantly pulling object’s toward the center of the Earth g Earth • Object must be moving fast enough so that it goes around the Earth before it can fall g velocity Earth

4. How to do satellites get into orbit? • Object is in orbit when it continues to circle the Earth • Anything that orbits another celestial body (e.g. planet, moon, etc.) is called a satellite Earth

5. How fast is an Earth satellite going? • An object that is orbiting the Earth is going about 7.5 km/s • 22,000 mph!!!!! • Could go to California and back in about 15 min • About 400 times faster than your car on the highway • About 40 times faster than a jet airplane

6. Rockets used to launch satellites into orbit • Rockets are used to launch satellites into orbit • Get the satellite to a high altitude first • Then turn the satellite perpendicular to the surface of the Earth • Why? • Get out of dense atmosphere first to reduce drag • Then get maximum effect of rocket by turning perpendicular to gravity velocity g

7. What kind of satellites are launched into orbit? • There are many types of satellites launched into orbit • Telescopes: why? • Communications: why? • Navigational: why? • Spying: why?

8. Every satellite is similar • Every satellite has the same main parts that can be compared to a human body • Structure to hold parts together ______________ • Metal and plastic boxes, plates, and screws • Computer to control satellite  ________________ • When to move, when to communicate, etc. • System to power all the parts ________________ • Batteries, solar panels, nuclear reactor, etc. • Covering to protect all the parts  ______________ • Foil, cloth, etc. • Propulsion system to move satellite  ______________ • Rocket, yo-yo, etc. • Systems to communicate  _________________ • Radar, transmitter, etc.

9. Every satellite is similar • Every satellite has the same main parts that can be compared to a human body • Structure to hold parts together Skeleton • Metal and plastic boxes, plates, and screws • Computer to control satellite  Brain • When to move, when to communicate, etc. • System to power all the parts Heart and lungs • Batteries, solar panels, nuclear reactor, etc. • Covering to protect all the parts  Skin • Foil, cloth, etc. • Propulsion system to move satellite  Arms and legs • Rocket, yo-yo, etc. • Systems to communicate  Eyes, ears, and mouth • Radar, transmitter, etc.

10. Spacecraft for humans are different • Larger Need more room for humans to sleep, work, and exercise • Oxygen system  need to have oxygen supply for humans to breathe • Better protection  cannot be too hot or too cold • More reliable  cannot have anything go wrong • Need windows  humans need to be able to look around or they will be very uncomfortable

11. Debris in space • Natural Debris • Asteroids, Comets, Meteoroids, and Micrometeoroids • Some pass through the near-Earth space • Most are very small – like sand • Artificial (man-made) Space Debris (called Orbital Debris) • Sputnik 1 launched October 4th, 1957 • ~ 75 spacecraft launches per year • ~30,000 large objects created since Sputnik • ~10,000 still in orbit • Only 6% still functional spacecraft • Remaining objects are Orbital Debris

12. What is orbital debris? Orbital debris is all space objects that are non-functional and man-made • Fragmentation Debris (~1/2) • Break-ups of satellites • unused fuel, dead batteries, etc. • Productions of deterioration • Paint flakes, thermal blankets, etc. • Rocket Bodies (~1/5) • Mission-related Debris (~1/5) • Refuse from human missions • Objects released from spacecraft • Deployment and operation • Non-Functional Spacecraft (~1/5)

13. Orbital debris characteristics French Cerise spacecraft struck by fragment from Ariane rocket body explosionin 1996 • ~ 11,000 objects greater than 10 cm in diameter • These objects are tracked by the United States Space Surveillance Network using radar and optical systems • ~9,000 catalogued objects in both lower Earth orbit (LEO) and geosynchronous (GEO) orbits • Will cause catastrophic damage upon impact • ~100,000 objects between 1 and 10 cm • Most are not tracked objects because they are too difficult to observe with ground-based telescopes and radars • Cannot be shielded against nor maneuvered around debris this size • Many millions of objects smaller than 1cm • Are not tracked for same reasons as above -- they are too small • Many of these debris can still cause significant damage to spacecraft Crater on Shuttle windowfrom remnants of a solidrocket firing (i.e. soot)that required window tobe replaced - $50k!!!

14. Orbital debris does not go away… • How long orbital debris stays in orbit depends upon the altitude of the orbit • a few days if altitude is less than 200 km • a few years if altitude is between 200-600 km • decades if altitude is between 600-800 km • centuries if altitude is greater than 800 km • “forever” if altitude is 36000 km or greater • “Orbital lifetime” also depends on the characteristics of the debris and even the solar activity • Why?

15. Controlling Orbital Debris • NASA Safety Standard 1740.14 • NASA has adopted a policy to control the generation of orbital debris • All NASA flight projects are now required to provide debris assessments as a normal part of the project development. • U.S. Government Orbital Debris Mitigation Standard Practices • In 1997, the working group created a set of U.S. Government Orbital Debris Mitigation Standard Practices . • Based on a NASA safety standard of procedures for limiting debris, the Standard Practices are intended for government-operated or -procured space systems, including satellites as well as launch vehicles. • The interagency group has shared the guidelines with the aerospace industry to encourage voluntary compliance.

16. What goes up must come down! • About 1 large (bigger than a softball) object comes back to Earth from orbit (deorbits) each day • Most burn up in the atmosphere but a few fall to the Earth • One person known to be struck by debris, but not hurt • Probability is 1 in a trillion (1/1,000,000,000) of injury from orbital debris • Risk due to lightning strike is 1 in a million (1/1,000,000) per year in the US • Have you ever been struck by lightning? • January 1997, Texas USA • 500-pound stainless steel fuel tank, part of a Delta II upper stage rocket • April 2000, Cape Town South Africa • Pressurization sphere

17. Potential Projects • 1. Launch satellites into orbit • 2. Satellite design • 3. Design a Mission to Mars • 4. Reduce orbital debris • 5. Reduce hazard from objects coming back to Earth

18. 1. Launch satellites into orbit • Problem: It is expensive to launch satellites into orbit. As you have learned you must get a satellite going very fast at a high altitude for it to “reach orbit”. • Challenge: Design a new way to launch satellites into orbit from the parking lot of GBW.

19. 2. Satellite design • Problem: Satellites must be tough enough to be launched into space but have all of the major parts as you learned about earlier: structure, computer, power, protection, propulsion, and communications. • Challenge: Design a satellite whose job it is to listen for signals coming from outer space and send this information back to Mr. Kelly’s trailer at GBW.

20. 3. Design a Mission to Mars • Problem: Americans have sent astronauts to the Moon but now President Bush has said we will send humans to Mars. • Challenge: Design a spacecraft to send Mr. Kelly, Ms. McNeilly, and Ms. Cleveland to Mars. Do a good job, we want them back!

21. 4. Reduce orbital debris • Problem: You have learned that there is a lot of refuse (old satellites and fragments) orbiting the Earth and posing a danger to functioning satellites. • Challenge: Propose one or more ways to prevent the continued increase in orbital debris and to remove orbital debris that is already in space.

22. 5. Reduce hazard from objects coming back to Earth • Problem: Thousands and thousands of pounds of metal satellites get launched into space every year and discarded when done with their mission. Eventually this material will fall back to Earth. • Challenge: Propose new approaches to ensure that the objects that return to Earth do not hurt anybody on Earth.