(Author's note: This is a file I put up for public view on July 17, 1989, on the GEnie public computer network. I had earlier given this as a brief talk and handout at a small meeting of a group I had just met, who called themselves the SSI Space Studies Team, led by Randy Gigante. This is provided to example the efforts I have made to get this potentially extremely important information out to a presumably intelligent and responsible humanity. James E. D. Cline, on 2000 10 11.)
Number: 927 Name: LONGTRANS 2
Address: J.E.D.CLINE1 Date: 890720
Approximate # of bytes: 20160
Number of Accesses: 15 Library: 3
This is part of a talk given to the SSI SST, summarising the Mooncable
Project, the Two Body Orbiting Skyhook, and the KESTS/GEO Habitat
LONG SPACE TRANSPORTATION STRUCTURES AND APPLICATIONS
by J. E. D. Cline 890717
Prepared for presentation to the SSI Space Studies Team. This part of the talk will be devoted to a view of three unusual space transportation concepts:
The MOONCABLE PROJECT, a captive form of tensile structure, or tether, attached to the surface of a lunar body and supported by an adjacent gravitational well; supporting conductors that couple kinetic energy between the two gravitational wells;
The TWO-BODY-ORBITING SKYHOOK, a free spinning tether shuttling back and forth between two unequal gravitational wells, along two abruptly changing trajectories;
The KESTS / GEO HABITAT RING, which looks like a tether but is actually a very long dynamically supported compressive structure, connecting the bottom of a gravitational well with its associated geosynchronous orbit.
The picture of two objects in space connected by a long thin structure, is a common element among the subject concepts. The fundamental characteristics of each of these structures involve associated concepts, such as the Mooncable's zero-gee casting at L-1 of foamed material into atmospheric re-entry shapes; and the enormous ring of space habitats in GEO being accessed directly from the Earth surface by the KESTS structure concepts.
But first I would like to remind you that space, extraterrestrial space with its abundant resources, is essential to a continued expansion of a civilized human population while taking the load off of the environment that gave us life. Indeed, it might be said that Mother Earth is very pregnant with humanity, and must give birth soon or both Mother and child will perish! Perhaps it is fitting that the form and function of the following proposed supply links resemble umbilicals. In that service, then, the following inspirations are offered you.
THE MOONCABLE CONCEPT:
Reference figure 1.
The Mooncable concept is a long tensile structure balanced across the L-1 libration point between the Earth and the Moon, and attached to the lunar surface at one end. With essentially equal weights in either direction from L-1, it hangs in place, forming an energy tunnel from the lunar surface to a slightly lower gravitational energy level 1/6 the way into the Earth's gravitational field. The structure is made of fiberglass, which has a strength of 500,000 lbf due to being made and used in a hard vacuum...there is no air to force its way into the surface microcracks that are the primary breaking mechanism on Earth. The structure is tapered to provide a constant-stress-crossection, thickest where it passes through L-1. Conductors along the length of the structure couple energy generated by payload braking down the Earthside of the cable, over to the Lunarside of the cable to lift more payload up to L-1, in a process analogous to a siphon. In the initial version of the concept developed in 1971-72, Lunar nickle-iron meteoric debris was to be hauled up to the manufacturing site at L-1, where solar furnaces melted this natural stainless steel and foamed it into molds casting it into re-entry glider shapes. After being dropped off the earthside end of the Mooncable, and remote-controlled atmospheric entry and gliding to near seaports, tugs would go out to retrieve the floating glider, haul it to port and saw it up for use in building freeway crash bariers, fireproof homes, and impact absorbing car bodies, for example. Pockets cast into the gliders would transport smaller amounts of other exotic materials and devices, such as hollow ball bearings, to Earth markets. Large spacecraft would have been built at L-1 for manned exploration of the solar system in relative comfort. It was to be built in a bootstrap process, where one of the remaining Saturn V boosters would be used to launch a craft to L-1, where a micro-diameter Mooncable of fiberglass would be despooled in both downward directions, and in the process soft-landing a robot glass-factory on the Lunar surface at that end of it. From the solar furnaces in that robot fiberglass plant, up would be lifted fibers to gradually increase the girth of the Mooncable....
The TWO-BODY-ORBITING SKYHOOK:
This is a modified Moravec-Skyhook useful for transferring payload from the surface of a moon to a point dominated by the parent planetary body, using the greater gravitational field of the nearby planet as an energy pump to sustain the process. A permanently orbiting spacecraft would dangle a long tether to briefly touch the farside of the Lunar surface as it passes by, grabbing awaiting payload. Then the combined whirling masses would continue on around the Moon in an orbit that passes near the Earth. At the precise instant that the whirling tethered mass pair has the payload deepest in the Earth's gravitational field, the payload would be released, restoring the kinetic energy to the spacecraft that was given up when the pickup was made off the Moon. The tether would be reeled in or let out before release, to compensate for varying payload mass when restoring kinetic energy to the spacecraft...letting the whirling payload drop deeper into Earth's well before release would give the orbiting spacecraft extra energy, such as for compensating for having some of the payload move aboard the spacecraft, for example. The tether attachment on the spacecraft would have to loosely spin around its CG, like a yo-yo with a loose string, or a "Y" fitting to either side of craft's CG, unless it was unmanned and didn't care if it wobbled erratically. The spacecraft-skyhook would then continue on back to pick up another payload off of the Moon. Reference figure 2.
This concept I feel the least comfortable about. Energy-wise, it seems plausable, being able to freely supply its own transportation energy, like the siphon-like Mooncable concept. However, the orbital mechanics is very shaky; Kepler's laws are not yet fully in my conceptual working grasp.
It must cycally shift between two orbits, due to the abrupt energy transfers at the pickup and release points. It may be limited to a single spacecraft/payload mass ratio to enable the moon-to-planet path. It may require unmanned operation, due to the abrupt accellerations at the pickup and release points...or at least crews chosen for iron-gut qualities!
A supply of reaction engine fuel would be needed on the spacecraft, to be used in case of ever missing a payload pickup, to return to Earth vicinity and again to go back to Lunar pickup point for another try. If the clockwork never fails, this seems to provide extremely energy-efficient payload transportation from Moon surface to an energy level somewhat less than 5/6 of Earth's gravity well.
KESTS/ GEO HABITAT RING:
Kinetic-Energy Supported Transportation Structures, and implications for massive early true space colonization:
Reference figure 3.
The KESTS--acronym for Kinetic-Energy-Supported Transportation Structures--are so novel to our conventional reaction-engine-technology-thinking, and so ripe with evocative implications for massive transportation links between Earth surface and Geosynchronous Earth Orbit, that perhaps it is worth starting thinking the concept from scratch. So let's mentally synthesize this together, right now, setting aside the critic part of our mind until hearing out the development of the concept as it currently stands. Picture a small object, frozen in motion as it passes by you faster than orbital velocity. It is going so fast that it would escape out beyond GEO, were it not for the presense of the atmosphere, which would disipate its kinetic energy as it burned it up like a meteor.
However, now add to this picture a tube in which the hurtling object moves; the tube occupies the exact trajectory path of the speeding object, and excludes the air from the object's path, so the object doesn't burn up. Now let the hurtling object multiply itself, become a constant stream of similar objects, all moving in the vacuum inside the tube along the trajectory path. Add appropriate electromagnetic and electrostatic fields between the tube and the stream of speeding objects which flows within it, such that the fields prevent the objects from physically touching the tube wall, and also drag slightly upwards on the tube, supporting the tubes's weight in the Earth's gravitational field. Let there be a second stream tube attached to the side of the first one, which has its stream going in the opposite direction from the first one. Picture this pair of fast stream tubes as they form a path almost horizontally past you, curving out and away from the Earth's globe, reaching out to GEO above the equator on the far side of the Earth from you. Create accellerators here on Earth and along its loops in space, supplying energy to replace losses in the system. Now picture payload boxcars travelling along the outer side of this pair of tubes, which are lifted and held away from the kinetic energy stream, by the same magnetic fields that hold the tube away from the stream pair. See these boxcars carry people and materials between Earth surface and GEO. See space settlements being built in GEO out of materials brought up along the KESTS. Perhaps these space settlements are similar to the Island One Stanford Torus designs, each a self-sufficient habitat for 10,000 people. See many of these KESTS, linking each nation to some part of the GEO Habitat Ring, being built now mostly out of Lunar materials. Mass drivers/catchers, or Mooncables, or Two-body Orbiting Skyhooks, or more KESTS on the Moon, are providing economical transfer of material from the Moon to build the structures in GEO. Picture the huge robot assembler- factories building the segments of the Banded Torus growing to eventially completely ring the Earth in GEO, 1.5 million of the Island-one's, each one providing home for 10,000 people and the agriculture and industries to support them there. Picture billions of people living in this GEO Habitat Ring, generally living in peaceful, constructive harmony together. See a spacefaring civilization starting to reach out from there toward the other resources in the solar system, bringing a multitude of Earth's lifeforms along with the people as they go. Feel the adventure of building the KESTS and GEO Habitat Ring, much as it felt to help build a treehouse as a youth, and the sense of safe haven there high above the ground.
Thank you for building this picture with me.
Consider starting small. If the stream tube is only 20 thousanths of an inch in diameter each, it would only occupy a volume equivalent to a cube 50 feet on a side, coiled on the Earth surface before rising up toward GEO. Such a tube might use a stream composed of a fiberglass filament with steel particles embedded periodically along its length. If instead of looping around the Earth, it went upward to a reverser of the stream which would have to be light enough to be lifted by the thrust of the force the stream bouncing back down the second tube back toward the Earth, where it would be re-accellerated again for its upward direction travel. Shifting the CG of the reverser with respect to the force of the stream reversing process, would provide a steering mechanism. Such a tiny version could go up and come back down when task is finished; it could be used to deliver respectable amounts of fiberglass to GEO; bundles of them could be used to support huge payloads.
One short-term use of these KESTS is perhaps the one most likely to attract the attention of contemporary America: providing large amounts of electrical power to earthsurface power distribution networks. The KESTS is used as an energy delivering system. The principle is that SSPS, Satellite Solar Power stations, hovering alongside a KESTS to provide power to maintain its support and materials transport function, would also pour accelleration electromagnetically to the downward direction stream. The energy from sunlight up there is converted into kinetic energy. At the earthsurface terminal, electrically conductive coils resist the pulses of magnetic energy driven by the mass stream's magnets, slowing the stream there slightly, and absorbing the kinetic energy by converting it into the current generated by the pulsing magnetic field of the stream. This electrical current would be rectified, inverted, and synchronized with the 60 Hz power grid frequency, for delivery to whoever uses electrical power. Advantage is that no fossil fuels are consumed, no nuclear energy is required, and no intense microwave beams from space are used.
To those who find special pleasure in deriving equations and playing with math, here are some interesting areas:
1) Derive the stream parameters in terms of stream density at the Earth terminal. This would make it easy to then model KESTS of 5 thousandths of an inch diameter, or of 5 feet in diameter.
2) Derive equations for weights to hang on the quasi-elliptical KESTS to either side of perigee, bending the stream so as to make necessary only one contact point on the Earth surface. Also consider cyclical adjusting of the weight position to compensate for the pull of the Moon and Sun on the considerable mass of the stream.
3) Derive equations for the magnetic field required to turn the stream around 180 degrees. If the weight of the necessary magnets and control equipment is less than the force of thrust as the stream pushes against the reverser, the up it goes! This would make possible different configurations of KESTS, analogous to Rod Hyde's "Starbridge" concept, as well as make possible the upward-steering emplacement concept as in the Microelevator concept, a KESTS to GEO that can be raised and lowered at will. Other forms of reversers can be considered, even simple compression springs, although this would limit the stream form to discontinuous packets of mass which would bounce off of the spring one at a time.
4) Examine the possible use of an electrostatic field to hold the stream away from the atmosphere-excluding tube walls. If it is feasable, then consider having the tube change to a mere skin, motionless to the surrounding atmosphere, sliding on the enclosed mass stream, and resisting the atmospheric pressure by transferring that inward pressure to the electrostatic field to the radial incompressability of the mass stream. This skin would have negligible mass compared to the stream within it, yet would still serve the function of blocking contact with the orbital-velocity stream with the Earth's atmosphere.
5) Calculation of the system energy roughly would be 1/2 MV squared, using the velocity at the Earth terminal exit, and the mass that of the entire orbital stream. The energy would then be divided into part potential energy in the stream as it rises losing velocity, and in losses from supporting the tube/skin, and losses due to moving the payloads up and down the KESTS.
6) Investigate effect on increasing velocity at entrance and exit on an extended GEO section of a quasi-elliptical KESTS, of tethered weights hanging toward Earth from that KESTS section.
7) Investigate the stress on the web coupling the positions of the up-stream tube with the adjacent down-stream tube. Intuitively this stress seems greatest at apogee; remember, one stream is in retrograde orbit.
"A New Dream for Our NASA: High Efficiency Transportation From the Moon Can make Moon/Null-g Products Low Priced on Earth", by J. E. D. Cline, Feb. 27, 1972.
"The Mooncable" A Profitable Space Transportation System" by J. E. D. Cline, March 25, 1972.
Correspondence from Francis Kemmett, Director of the Staff, NASA Inventions and Contributions Board, deferring consideration of "The Mooncable: A Profitable Space Transportation System"; dated June 23, 1972.
Article describing Mooncable Project, submitted to Carolyn Henson at the L-5 Society for publication in L-5 NEWS, Nov. 26, 1978. Rejected due to lack of prior formal presentation to AIAA.
"Intro to Mooncable" by J. E. D. Cline, GEnie Spaceport Library file #480,
"Mooncable Project 14", by J. E. D. Cline (J.E.D.CLINE1), GEnie Spaceport Library file #530, Sept. 9, 1988.
"MOONCBL-LOFSROM-RESPONSE", by Keith Lofstrom (TRANSONIQ), GEnie Spaceport Library file #542, Sept 18, 1988.
"Skyhook!" by Hans Moravec, L-5 NEWS Aug 1978 pp1-3,12.
"The Rocket/Skyhook Combination" by F. Burke Carley and Hans P. Moravec, L-5 NEWS March 1983 pp. 4-6.
"Space Inspiration", by J. E. D. Cline, Testimony given to the National Commission on Space, Nov. 14, 1985, GEnie Spaceport Library file #475, July 2, 1988.
"Conceptual Synthesis" by J. E. D. Cline, GEnie Spaceport Library file #634, Nov 20, 1988.
KESTS/ GEO HABITAT RING
"Space Settlements: A Design Study", NASA SP-413, 1977
"The Launch Loop" by Keith H. Lofstrom, L-5 NEWS Aug. 1982, pp. 8-9.
"The Starbridge", by Rod Hyde, talk given to Silicon Valley L-5, (1984?)
"The Launch Loop" by Keith Lofstrom, ANALOG, pp.67-80.
"The Texas and Universe Railroad", by Earl Smith, L-5 NEWS, Nov. 1985 pp.9-11.
"Power + Transportation", by J. E. D. Cline, GEnie Spaceport Library file #553.
"Microelevator Vers 2", by J. E. D. Cline, GEnie Spaceport Library file #581.
"Microelevator Import", by J. E. D. Cline, GEnie Spaceport Library file #592.
"GEO'S UMBILICAL" by J. E. D. Cline, GEnie Spaceport Library file #629.
"GEO HABITAT UMBILICAL 2" by J. E. D. Cline, GEnie Spaceport Library file #690, Dec. 29, 1988.
"HWY TO EARTH'S GEO RING" by J. E. D. Cline, GEnie Spaceport Library file #747, Feb.9, 1989.
"High Suburbia Commute" by J. E. D. Cline, GEnie Spaceport Library file #819.
"Passive Stable KESTS" by J. E. D. Cline, GEnie Spaceport Library file #880.
"GEO TREEHOUSE" by J. E. D. Cline, GEnie Spaceport Library file #881.
"LONGTRANS" by J. E. D. Cline, containing most of this talk, GEnie Spaceport Library file #892. 890704.
Contact info: GEnie "mail" address: J.E.D.CLINE1
For a copy of the page of illustrations referred to in the above text, send a stamped, self-addressed envelope to the author: J. E. D. "Jed" Cline 5632 Van Nuys Blvd. Ste 110 Van Nuys, CA 91401 Phone: (818) 909-0143
Copyright (C) 1989 by GEnie, SPACEPORT UNLIMITED, and J. E. D. Cline. Permission is granted for material to be distributed without restriction, provided credit is given to GEnie, SPACEPORT, and J.E.D.Cline.
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