"Howard Eisenhauer" wrote in message
news
On Fri, 25 Jun 2004 22:42:15 -0700, Richard Riley
wrote:

On Fri, 25 Jun 2004 20:47:03 -0500, Big John
wrote:

:Scientist Sees Space Elevator in 15 Years
:
:By CARL HARTMAN, Associated Press Writer
:
:WASHINGTON - President Bush (news - web sites) wants to return to the
:moon and put a man on Mars. But scientist Bradley C. Edwards has an
:idea that's really out of this world: an elevator that climbs 62,000
:miles into space.

OK, so you use a whole lotta solar power beamed at your cart to climb
62,000 miles straight up (without becoming a crispy critter, but
that's another topic).

Where are you going to get the mass and energy to accelerate yourself
laterally to reach orbital velocity? Aren't you just going to
decelerate the beanstalk and send it whipping to the west as the earth
rotates beneath you, winding the beanstalk along the equator like an
earth sized yo-yo?


At 24,000 mile you're at geosynchronis orbit, ready to float free. If
you want an orbit lower down you just burn a little rocket fuel (that
you brought up with you) to slow down & drop lower.

The other 38000 miles of line wants to pull away from the Earth so
acts as a counter weight keeping the whole thing pulling straight up.
If you keep going past the 24,000 mark before cutting loose you start
picking up the velocity you need to get to the Moon, as well as many
other fun spots around the system .

Any deflection caused by sending payloads up gets cancelled out by
stuff coming back down, i.e "My Parents Went to Jupiter & All They Got
Me Was This Cheap T-Shirt" x 10-6.

H.

This space elevator thing is elegant in a Newtonian sort of way but I
suspect that there is a lot more to it that hasn't been completely thought
out.

They say put it on the equator where the winds are low. Well, they are low
most of the time but there is always the occasional typhoon.

Then there are the electrical effects. A carbon nanotube cable will conduct
electricity pretty well. Some claim it's a room temperature superconductor
candidate. A tropical lightning strike can be several million amps and this
cable will be a pretty good lightning rod. There's the induced voltages
too. The normal atmospheric potential gradient is several million volts per
meter.

What about tidal effects? Twice each day the Moons gravity will pull on the
structure.

Bill Daniels