Day 26 of 30 2006
Day 26 of 30 "Building Up"While Idealiana re-bonded with her parents, she also was learning about the new kind of transportation system they were going to build. It seemed incredible, a non-tether structure so big it would reach from ground up to GEO and go entirely around the planet in so doing. The Space Elevator she understood from when she was a child, living on the floating island for awhile while the former small Space Elevator was being built and anchored there. The tether had its weight supported by mass swinging around, like a ball on the end of a string being swing around, centrifugal force. The upward pull from a counterweight located on the tether on beyond GEO, as it was being swung around by the rotation of the planet itself, to balance the weight of the part of the tether that was between GEO and ground, along with the weight of its live loads, the payload-carrying vehicles moving up and down the tether. With a strong enough material per its mass, the tether could be in the form of a belt rolling around between two pulleys, one at each end, thus the belt also functions as a conveyor belt hauling material up and down between ground and its upper end or points between, such as GEO. Quite understandable.
But this other way of getting a structure from ground to GEO, although it too was supported by centrifugal force, was quite different. It did not use the centrifugal force generated by the planet swinging a weight around. It used the centrifugal force of a stream of mass circulating around the planet along a track, mass going faster than orbital velocity, so that its velocity in excess of orbital velocity expressed as outward centrifugal force against the track that constrained its path, and that outward force was "up" relative to the planet that the mass was circulating around, and so supported the weight of the track's mass. Circulating mass traveling at twice the orbital velocity all along its circulating path, could balance a track and payload mass equal to its own mass.
It was a huge perimeter electric motor, she could understand that, as electric motors were a favorite subject of hers from when she was a child. The circulating mass stream was the motor's armature. The armature was given a push as it passed through the earth terminal, then coasted around the loop, given another push each time it passed the Earth terminal's accelerator site. The armature also could electromagnetically drag other mass up with it, giving up a little of its kinetic energy in doing so, which would be replenished when it went through the ground site accelerator next time. That way, the payload-carrying spacecraft it was lifting, did not need to lift the mass of an energy source on its way up. And it was all-electric so eventually it could be powered entirely by solar-electric powerplants in GEO, which it would make possible to build.
So it was like the tether Space Elevator in what it could enable done. But the electric motor's armature had to be in discontinuous segments, as their distance between each other had to vary as they exchanged kinetic energy with potential energy as they rose and fell in the gravitational field of the planet. Keeping those armatures from bumping into each other required the motor to be a synchronous motor. The whole thing seemed a lot more complicated than the belt loop on pulleys of the anchored tether Space Elevator. Why do it that way? Both techniques for getting construction material from ground to GEO were all-electric and so ultimately could be powered from the Sun's energy as received in GEO. Both could initially be made of small cross-section and then be used to scale itself up to whatever payload-carrying capacity was needed for the job at hand.
Both had the problem that the orbital space between ground and GEO had to be swept clean, eventually, to avoid collision with the structure; but with easy and cheap access to GEO, there was little if any need for satellites in Low Earth Orbit anymore anyway. That was why the space access structures had not been built back when they could have been built in time to have provided the resources to have prevented the big mess civilization was not in, since it would have competed with existing aerospace which used LEO for its business, and business profit was what ruled. People were so irresponsibly shortsighted, she complained to herself, and now they were a dying civilization because of it. And killing a planetary ecosystem along with themselves. Was mankind too powerful for its own wisdom? Or could mankind pull the fat out of the fire? It looked like it was up to this project to see if it could e done, since the powerful business masters were sunk in their ego-driven luxury, partying until the show was over. They wouldn't have lived forever anyway, right? Yuck, what monkeys, she thought. Just very powerful cunning monkeys, addicted to playing games with each other, what ego-driven fun.
The tether material was the problem. It was reaching the limit of physical substances' molecular bonds strength for the mass of the atoms involved. Since it was operating near its limits of strength, it had little resiliency for transients. And in real systems, there inevitably would be transients. Since the earth-encircling structure technique did not have this molecular bond strength to mass ratio limit approached anywhere in its structure, it would be more reliable in the long run, if its greater complexity was adequately coordinated. And the technology for the magnetic levitation synchronous track had yet to be proven, as it would only operate at high velocity in a hard vacuum.
She would focus on how to make those little armature segments the motor needed, that sounded interesting. And zillions of them would need to be made, a manufacturing task, something that was her speciality.
Copyright © 2006 James E D Cline
posted by Unknown @ 6:32 AM
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