1. Module A-3 Carbon Nanotubes

2. Space Elevators First elevator: 20 ton capa city (13 ton payload) Constructed with existing or near-term technology

3. Space Elevators

5. Challenges Induced Currents: milliwatts and not a problem Induced oscillations: 7 hour natural frequency couples poorly with moon and sun, active damp- ing with anchor Radiation: carbon fiber composites good for 1000 (?) years in Earth orbit (LDEF) Malfunctioning climbers: up to 3000 km reel in the cable, above 2600 km send up an empty climber to retrieve the first Lightning, wind, clouds: avoid through proper anchor location selection Meteors: ribbon design allows for 200 year probability-based life Damaged or severed ribbons: collatoral damage is minimal due to mass and distribution

6. Anchor Anchor station is a mobile, ocean-go ing platform identical to ones used i n oil drilling Anchor is located in eastern equator ial pacific, weather and mobility are primary factors

9. Processing Techniques

10. Discharges Cheap Yield ~30% Short (<50 microns) Random deposits

12. CVD Growth Mechanisms

13. MWNTs by CVD Methods

14. Single Walled NTs

15. Heterostructure Carbon nanotubes

16. Catalytic CVD Growth Hongjie Dai, Stanford

17. Catalytic Methods High potential for scale-up production Long lengths Multiwall CNTs Many defects in the materials

20. CNT for Electronics Carrier transport is 1-D. All chemical bonds are satisfied  CNT Electronics not bound to use SiO 2 as an insulator. High mechanical and thermal stability and resistance to electromigration  Current densities up to 10 9 A/cm 2 can be sustained. Diameter controlled by chemistry, not fabrication. Both active devices and interconnects can be made from semiconducting and metallic nanotubes.

21. Transport on a single CNT