SPACE ELEVATOR

SPACE ELEVATOR: A NEW WAY TO REACH THE STARS

The Space Elevatoris 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.

The Space Elevator in Science Fiction

Properties Of Carbon NanotubesStrong– 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.

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

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

Power BeamingPower is sent to deployment spacecraft and climbers by

laserSolid-state disk laser produces kWs of power and being

developed for MWatts Mirror is the same design as conventional astronomical

telescopes (Hobby-Eberly, Keck)

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

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

Advantages

Low operations costs - US$250/kg to LEO, GEO, Moon, Mars, Venus or the asteroid belts

No payload envelope restrictions No launch vibrationsSafe access to space - no explosive propellants or dangerous launch or re-entry

forcesEasily expandable to large systems or multiple systemsEasily implemented at many solar system locations

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.

Summary

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• Bonsor, K. (2000). How space elevators will work. Retrieved from http://www.howstuffworks.com/space-elevator.htm

• Clarke, A. C. (1979). The Space Elevator: “Thought Experiment” or Key to the Universe? Advances in Earth Oriented Applied Science Technology

• Georgia, F. (2006). The 62,000 mile elevator ride. Business 2.0. Mar2006 Vol. 7 Issue 2, p78-80.• Jorgensen, A.M. (2007). Passive radiation shielding considerations for the proposed space elevator. Acta Astronautica.

Feb2007, Vol.60 Issure 3, p198-209.• Markos, P.A. (2013). A heuristic approach for the positioning of elevator hoistways based on the utilization intensity

index. Architectural Engineering & Design Management Nov2013,Vol.9 Issue 4. • Nasa. (n.d.). Kennedy space center. Frequently asked questions. Retrieved from. http://

www.nasa.gov/centers/kennedy/about/information/shuttle_faq.html#1• Powell, J. (2006). Startram: an ultra-low cost launch system. AIP conference proceedings. 2006, Vol. 813 issue 1, p1071-

1082. 12p. • Pugno, N. M. (2006). On the strength of the carbon nanotube-based space elevator cable: from nanomechanics to

megamechanics. Journal of Physics: Condensed Matter, 18(33), S1971• Pugno, N.M.(2013). Towards the artsutanov’s dream of the space elevator. the ultimate design of a 35 GPa strong tether

thanks to graphene. Acta Astronautica. Feb2013, Vol. 82 Issue 2, p221-224.• Takeichi, N. (2012). Geostationary station keeping control of a space elevator during initial cable deployment. Acta

Astronautica. Jan2012, Vol. 70, p85-94.• Williams, P. (2009). Dynamic multi body modeling for tethered space elevators. Acta Astronautica. Aug2009, Vol. 65 Issue ¾.