1. SPACE ELEVATOR

2. SPACE ELEVATOR: A NEW WAY TO REACH THE STARS
The Space Elevator is a cable-like tool which could connect the Earth with a fixed structure in outer space. It would provide a permanent link between Earth and outer space.

3. The Space Elevator in Science Fiction

4. Properties Of Carbon Nanotubes
Strong
– 200 times stronger than steel.
– the first synthetic material to have greater strength than spider silk.
Light
– 1 square kilometre = 30kg
Flexible
– Compared to most materials.
Heat resistant
– resists burning like a metal.
Nanotube image from GNU free documentation license, courtesy of Michael Strock
Reference for weight info: K. Banerjee and N. Srivastava, "Are Carbon Nanotubes the future of VLSI Interconnections?", ACM Design Automation Conference, 2006, pp

5. Ribbon Design
The final ribbon is one-meter wide and composed of parallel high-strength fibers
Interconnects maintain structure and allow the ribbon to survive small impacts
Initial, low-strength ribbon segments have been built and tested

6. Climbers Climbers built with current satellite technology
Drive system built with DC electric motors
Photovoltaic array (GaAs or Si) receives power from Earth
7-ton climbers carry 13-ton payloads
Climbers ascend at 200 km/hr
8 day trip from Earth to geosynchronous altitude

7. Power Beaming
Power is sent to deployment spacecraft and climbers by laser
Solid-state disk laser produces kWs of power and being developed for MWatts
Mirror is the same design as conventional astronomical telescopes (Hobby-Eberly, Keck)

8. Anchor
Anchor station is a mobile, ocean-going platform identical to ones used in oil drilling
Anchor is located in eastern equatorial pacific, weather and mobility are primary factors

9. Challenges Induced Currents: milliwatts and not a problem
Induced oscillations: 7 hour natural frequency couples poorly with moon and sun, active damping with anchor
Radiation: carbon fiber composites good for 1000 years in Earth orbit (LDEF)
Atomic oxygen: <25 micron Nickel coating between 60 and 800 km (LDEF)
Environmental Impact: Ionosphere discharging not an issue
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
LEOs: active avoidance requires movement every 14 hours on average to avoid debris down to 1 cm
Health hazards: under investigation but initial tests indicate minimal problem
Damaged or severed ribbons: collatoral damage is minimal due to mass and distribution

10. Advantages
Low operations costs - US$250/kg to LEO, GEO, Moon, Mars, Venus or the asteroid belts
No payload envelope restrictions
No launch vibrations
Safe access to space - no explosive propellants or dangerous launch or re-entry forces
Easily expandable to large systems or multiple systems
Easily implemented at many solar system locations

11. Summary
The space elevator is a revolutionary Earth- to-space transportation system that will enable space exploration
Design, deployment and operational scenarios for the first space elevator have been put together. Potential challenges have been laid out and solutions developed.
Development of the space elevator requires an investment in materials and engineering but is achievable in the near future with a reasonable investment and development plan.

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