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 thatit 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 fromspace 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 onthe 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.

     REFERENCES:
 
     MOONCABLE PROJECT:
 
"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.

     TWO-BODY-ORBITING SKYHOOK:
"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, GEnieSpaceport 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 SpaceportLibrary 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 SpaceportLibrary 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 110Van 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.