Space Elevators
Michael Howard
10-31-12
Pros and Cons
 Benefits
 Cheaper space travel
 Allows for many more trips into space
 Problems
 Requires a very strong and light material
 Will be costly to build
What is a Space Elevator?
 Rope attached to the Earth near the
equator which extends directly into space
and is attached to a small counterweight in
geostationary orbit
 Will be able to transfer materials and
eventually humans into space for much
cheaper than it costs now
Why Does the Tether Stay Up?
 Because the force of
gravity at the bottom
and the
upward/outward
centrifugal force at
the top compete
keeping the rope taut
The Platform
 Will be placed along the equator so it will
be located in the same place in the sky for
ground observers
 Built on a ship so it can be moved
The Tether
 Will be made of 22,000 mile long carbon
nanotube strands because it is currently
the only option which has the proper
strength and is light enough
 Will need to be wider at geosynchronous
altitude where it will experience the most
stress and taper down as it approaches
earth
The Climber
 It will be powered by lasers and solar
power
 It is estimated that the climb will take
about 5 days
Climber
Counterweight
 Captured asteroid
 Space station above geostationary orbit
Benefits
 Currently, the cost to launch a shuttle is
about $10,000/lb
 Mechanical lifters attached to cable could
carry cargo up to space for about $100 to
$400 per pound
Elevator vs. Rocket
 While rockets will undoubtedly improve
greatly in efficiency there is a limit to how
efficient they can become
 The elevator will be the next step
Space tourism
 A space elevator could help many people
realize their dream of traveling into space
Problems with the elevator
 Will require a strong material such as
carbon nanotubes which we don’t currently
possess the ability to form into a long
enough tether
 Will the public be convinced it is a good
idea
Cost to build it
 The space elevator will be the longest
structure ever built but it will be simple
 Estimated cost to build the space elevator
is about $10 billion
 Approximate cost of building a space
shuttle is about 1.7 billion and it costs
about $450 million per mission
 Endeavor completed 25 missions before
being retired
Would it be Safe?
 Space debris
 Cable snaps
 Storms
 Terrorism
Conclusion
 The future of space travel
 Would set us on the path towards expanding our
space exploration to places might never reach
relying solely on rockets
 Philip Ragan, co-author of the book "Leaving the
Planet by Space Elevator", states that "The first
country to deploy a space elevator will have a 95
percent cost advantage and could potentially
control all space activities."
Parting Words
 “We put more effort into getting efficient at
what we know how to do than into learning
how to do new things. It's almost as if
we're content that as a civilization we've
arrived at our final destination and all that
needs to be done is get comfortable.
Judging by history, this is almost a sure
sign of the beginning of decay.”
References
 http://www.pbs.org/wgbh/nova/space/spac
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e-elevator.html
http://www.howstuffworks.com/spaceelevator.htm
http://www.spaceward.org/elevator
http://phys.org/news151938445.html
http://nextbigfuture.com/2009/01/cambridg
e-making-carbon-nanotubes.html