16-02-2010, 08:04 AM
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SPACE ELEVATOR A NANO DREAM
THE Concept
A 35000-mile long cable
will hang in space, stationary and tight !
CentripetAl force
The space elevator is a cable that can be ascended from Earth to space, with one end fixed on earth.
Build in a similar way to how difficult bridges were built in the past. In building a bridge, the first thing that `was done was a small string was thrown or shot across a canyon. Then a larger string is attached to this first small string and pulled across.
Spacecraft
Unique requirements , require a specific set of mechanical actions.
Cable deployment
mechanical system for deploying the cable
deployment
speeds of 200 km/hr and 1000 RPM
end of the cable will be a small self-contained craft.
impart a small amount of angular momentum to the cable as it is initially deployed.
ANCHOR
Minimum environmental hazards
Global distribution of lightning activity , cyclonic storm and smaller storms.
Locating a power beaming station near-by
Ease of construction, access and operations
Location : Floating platform located off the
coast of Ecuador or a mountain-top location either
in Ecuador or Tanzania.
TECHNICAL SPECIFICATION OF SEA LAUNCH
Refurbished oil platform
Overall dimensions: 133m x 67m
46,000 tons displacement
Power plant: 26,800 horsepower (20 MW)
Self- propelled transit speed: 12 knots
Cost: ~$100M (our unofficial estimate)
18 months for refurbishment
Home port: Long Beach California
POWER BEAMING
Laser Power Beaming
Sea level beaming
atmospheric distortion reduces efficiency
Long term broadening can be classified as
1. Short term broadening and
2. Beam wander
Why Carbon Nanotubes?
extremely long molecular tubes of carbon where the atoms are arranged in a pattern
stronger per kilogram than any other material by a factor of 40.
a fiber made of carbon nanotubes 1/8" (3mm) in diameter could support 45 tons (41,000 kg).
Production of Nanotubes
Pulsed laser vaporization
Pulsed lasers strike a catalyst of graphite and metal - cobalt and nickel - which are vaporized into a tube filled with pressurized argon in an oven heated to 1473 degrees Kelvin.
Electric arc discharge
The carbon is also vaporized. But instead, this time catalysts of nickel and yttrium are vaporized from an anode when it's hit with 100 amps of electricity at 35 volts. The nanotubes self assemble in a stainless steel chamber filled with low-pressure helium gas, cooled by water.
High-pressure carbon monoxide (HiPco) is reacted with iron pentacarbonyl, which is also under high pressure, and heated. The iron clusters phase into a gas and the carbon atoms grow into nanotubes around those clusters.
straight, clean, 12 micron diameter single-walled carbon nanotube bundles
Application
Place heavy and fragile payloads in any Earth orbit or send them to other planets.
Deliver payloads with minimal vibration.
Bring heavy and fragile payloads down from space.
Sensitive global monitoring of the Earth and its environment with much larger and more powerful satellites.
Orbiting observatories and interferometers many times more powerful than Hubble or any Earth-based radio telescope.
Improved space station
Military operations would be dramatically altered with almost unlimited access to space.
Conclusion
As often the cascade of progress is barely imagined when that first small step is taken. The space elevator could be a catalytic step in our history. We can speculate on many of the things that will result from construction of a space elevator but the reality of it will probably be much more.
