2006 day 2 of 30
2006 day 2 of 30 JEDCline modified aThe drum in GEO had finished de-spooling the remaining twisted carbon nanotube tether, leaving only the half loop around the drum, and all the tether material was now dangling toward the Earth.
And on the floating artificial island, Catalia and Improy had their hands full. they had to do everything remotely into the tube which constrained the motion of the tether's end, in the relative motion from wind and tides. The two triplets of twisted nanotube monofilaments, almost invisible to the eye, were separated out, and each was securely clamped to the unwinder fork. Then the two sets of strands were slowly unwound, counted to match the number of twists applied during the original manufacture of the spooled tether. The number had to match exactly, otherwise there would be a crossover somewhere, and abrading would happen once it went into motion as a belt between the two pulleys. At the same time it was untwisted, there had to be absolute restraint of both strands sets, or there was risk that when they were finally untwisted completely, one strand would be slightly heavier than the other and begin to fall down, raising the other strand set up, making it even lighter, and causing cascade failure collapse of the structure, dumping it all back to the Earth surface.
And they had to splice the two triple monofilaments together as a final step, attached together so securely the joint could bear the load of the entire weight between GEO and surface. The splice had to be made when the two strands were freed from one another, their most vulnerable time for weight unbalance pulling one side down. And the excess length had to be snipped off to a length that would never bottom out in the vertical path constraint tube on the floating platform.
Although the whole process had been thought out long ago, it had never been done in physical reality. So each step was part per the book, and part was winging it as the process unfolded in physical reality, truly massive forces in delicate balance.
The couple now worked on the same shift, as the tasks required their close coordination hour after hour. Catalie's intuitive sense of the overall wholeness of the ongoing unfolding events, was balanced by Improy's continual referral of the procedure, and entry of data or marking of checkboxes. Occasionally they would modify or insert the instructions to some facet newly become apparent.
When some stage of the procedure allowed them relaxation time, as lovers they renewed their bonding so helpful in the ongoing tasks of the day too, contributing greatly to its chances of success. What they were doing would have taken dozens of experts normally, but those experts were fearfully far away, memory of the destruction in the previous attempt keeping them away. The internet provided access to their advise, as well as a way to give them updates on the ongoing progress details. But the lover's sleep together time and recreation break moments were theirs alone, and savored to the fullest.
During one such break time, Catalie called Improy over to look into the stereo microscope. She had a hobby of observing a particular kind of sea critter, a kind related to the little rolley-polley bugs in her garden back home, yet which had amazing diversity on the vast sea floor. Peering into the microscope, Improy was immediately plunged into the microscopic world of marine crustacea, and he saw one of the males, with its pair of tail-like hind structures and a pair of horn-like structures on its head, scurrying around with three small versions of itself on its back. "See how the youngsters scurry to get on the back of the large male when a threatening situation comes along", Catalie guided. "There is more to the lives of these sea creatures than one would expect. See how their big eyes sometimes seem to be aware of you looking in the microscope down at them." Improy grunted something non-commital, but then looked over at the computer display which was the output of a tiny camera mounted on the outside of the floating platform's shell, long encrusted with the makings of creatures that inhabit the pilings of waterfronts around the world. "Somewhere, sometime, in its past, this oil rig must have been located off the California coast. These are the same Sphaeromatid species I found on the marina pilings in the Los Angeles area a couple of years ago", Catalie chattered on. "No way could have gotten here through the ocean on their own." She too watched the computer video display of the busy lives of the teeming microvillage on the hull of their floating island, one of her favorite relaxations. In so many ways they are like bunches of people. "Yet they are so tiny, and look as strange as the "bug eyed monsters" of early science fiction writers fantasizing life on other planets, yet here it is, right here." Tiny but cute bug-eyed monsters, neighbors only tens of meters away from where the adventure of connecting to high earth orbit was unfolding. She turned off the microscope light, picked up the petrie dish and carried it off, and soon Improy could see the little crustaceans dumped back into the view of the micro videocamera mounted on the outer hull, where they scurried around frantically until re-discovering their homes.
Breaktime over, they went back over to the structure which had once held oil drilling machinery, now housing the mechanisms preparing connection to far above instead of to far below. The untwisting of the pair of triple-monofilament carbon nanotubes was getting close to competion. The exact untwisting was determined by sending a pulse up the separated pair of tethers, which would send a reflection back down early if the two crossed somewhere below GEO. When there were no lower reflections happening, the untwisting ceased; the tether was allowed to stabilize then to verify that indeed the two sides were parallel and no crossing existed anywhere in the 36,000 km length.
Halfway down the 50 meter long vertical tube in the seagoing platform, a fresh pair of clamps were applied to the two strands as security. Then just below that, they severed the excess tether length, unraveled the three monofilaments, then re-wove them into a section of six interwoven monofilaments to form the splice. The spliced area of the tether was then surrounded by a vacuum chamber, where it was pumped down to a hard vacuum, then a flood of carbon atom gas was deposited all over the splice area, the atoms aligning themselves to unite across the original strands, strengthening the bond within the splice. A plastic sealant was then applied over the area, a plastic that would protect the area from oxidation during its ascent through the atmosphere into the hard vacuum above, where the sealant plastic would vaporize, its job done.
Then the big test began. Command was beamed up to the drum satellite in GEO to roll the pulley, lifting one side of the pair of tethers and lowering the other side, it all in a great loop at this point. Clamps had been removed down below, so the splice went up and soon through the atmosphere, as the continuous belt went around between the two pulleys, one in GEO and the other in the tube on the floating artificial island. It was days of wait, as the drum rotation was constant and the distance great, The load on the splice increased to a maximum as it reached GEO, then was bent as it passed over the GEO pulley, then supported the full weight of the downward tether. And it held.
Their next milestone was to attach a fourth carbon nanotube filament to the upward moving side of the loop, seamlessly laying it along the twist of the original triplet of filaments as it rose. This required a bobbin containing the entire length to be emplaced for a full up and down distance, 72,000 km of nanodiameter carbon nanotube filament. Splice of the added filament ends were arrange to be ten percent of overall tether distance, so as to not overlap yet being of some assistance as the original splice neared the top of the tether. This was the proving out of the scaling up construction process, key to an economical construction of a Space Elevator of sufficient girth to be able to lift the materials needed for huge constructions works high in orbit.
When two more strands had been added, they were able to begin adding two new strands per loop movement, exponentially increasing the rate of increase of girth of the overall tether pair. Eventually the additions were done laterally, gradually forming the tether into two parallel ribbons that flowed between the earth and space pulleys.
When the weight of another layer of ribbon girth equaled the weight of a solar panel for the GEO satellite, for the next several circuits of the tether loop, instead of tether material going up, solar panels went up, clamped on the ribbon as it left the deck of the floating island, and stripped off just before reaching the pulley in GEO. The original design of the GEO satellite had provision for robotically distributing and attaching the added solar panels, which enabled lift of greater loads up thereafter.
The increase of tether crossectional girth then resumed, until the tether could lift a small spacecraft carrying a person to GEO. The limits of the original chemically powered launch vehicle emplaced satellite to expand itself had been reached, and construction of the larger facility in GEO required human presence from then on.
Tugs brought in more surplus floating oil rigs to be lashed to the original remaining pair of platforms, and an influx of personnel flowed back to populate the increasingly large artificial island there in the equatorial Pacific Ocean. The continuous existence of the dual tether increasingly gave people confidence of probable survival, especially as its girth and therefore strength became quite substantial and would be able to take a hit from increasingly large orbiting debris and still survive to be repaired.
The scaling up of strength of the tether again ceased, as more solar panels were sent up, then Improy was lifted up the tether in a mini-habitat.
Arriving in GEO, the habitat module was unhooked from the tether, and Improy spacesuited went out to begin assembling the new solar panels to increase the power of the drum lift, and soon a second electric motor was lifted up and joined to increase the lift power of the tether. The rate of tether loop movement was then speeded up, reducing the lift transit time; more components of the initial permanent manned facility were lifted along with sawdust-laced water ice which was placed around as a passive shield against solar storms that eventually would pass their way.
Improy had only a week up there before the DNA repair mechanisms were getting used up in his body, so he went back down to the artificial island to recuperate, providing excuse for a huge celebration of having shown human travel to orbit and back on a space elevator for the first time.
posted by Unknown @ 9:26 PM
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