Replies

I have my doubts about the "Space Elevator". At Geosync, a satellite experiences gravitational "tugs" (drift) not only in-track but cross-track as well. This drift is induced by; A) the non-spherical shape of the Earth and B) a Moon that does not orbit directly over the equatorial plane. For any satellite in geosync, periodic Delta-Vs must be accomplished for station keeping.

Usually, there is a maximum equatorial ground track distance that falls within an acceptable margin from the desired sub-point. Since geosync satellites tend to drift in one direction, station-keeping usually means using a thruster of some kind to position it at the "uphill end" and let it drift to the "bottom end", re-firing the thruster "pushing" the satellite back to the "up hill" and letting it drift once again over and over for the life of the vehicle. The cross-track drift ends up looking like a figure eight plotted against the ground. This figure eight gets bigger with age as the drift grows. Again, Delta-Vs can keep your bird on station for the life of the satellite.

OTOH, with a Space Elevator, you don't have these luxuries. You must not induce a vibration (or standing wave) in this structure. Remember the Tacoma Narrows Bridge? Even if your structure is strong enough to span the "gap", (23,000 miles in one heck of a gap) you must take into account vibrational stress.

The other issue is the electrical potential that will be present between the top of the elevator and the bottom. How do we discharge/ground that safely?

I know I am sounding like a wet blanket here, but like the Orion project, IMHO, the Space Elevator (although intriguing), will remain a "paper" project.

NOT ROCKETS !!!! ROCKETS ARE NOT FOR COMMERCE !!!

We are using rockets for commerce as we speak. Someone is making money for getting all those satellites up there.

BTW, Look for part two (and possibly a part three) to my previous post tonight and tomorrow, should there be a part three.

207 - You made some compelling arguments against the space elevator, but you limited them to scientific arguments.

There are lots of engineering and commercial arguments too.

"NOT ROCKETS !!!! ROCKETS ARE NOT FOR COMMERCE !!!
We are using rockets for commerce as we speak. Someone is making money for getting all those satellites up there."

True, but this is not 'space' travel - Low Earth Orbit is exactly that - essentially high flying rocket planes, which utilize earth's gravity for continuous propulsion, once the rocket engines burn out.

You need to get out of your limited thinking about rockets for space travel. Carrying your own fuel supply with rockets for long distance travel is just not feasible on any commercial scale.

And I don't think that Laura Bush has a neckless to sell to buy a moon rocket (like Queen Isabella).

I would agree that we don't have the technology for a commercial space elevator just yet, but I think that some of your concerns are addressable. The counterweight would be considerably beyond the geosynch point, and the tension could overcome any tendencies to drift. the tether would be a flexible fabric. I think vibrations could be damped, although I am not an engineer. It looks like a rather straightforward problem.

Exectrical generation is an interesting side effect, but the fabric would be carbon. Perhaps the electrical potential between points on the ribbon could be harnessed to run the elevator.