GeSp530

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Number: 530 Name: MOONCABLE PROJECT 14

Address: J.E.D.CLINE1 Date: 880909

Approximate # of bytes: 25200

Number of Accesses: 24 Library: 3

Description:

This concept offers highly energy-efficient transportation from the Lunar surface, processing at L-1, and delivery either to Earth-surface markets, or to spacetugs at L-1 bound for L-4, L-5 or elsewhere. BASIC program included for calculating cable sectional area vs distance, demonstrating adequate strength of lunar fiberglass in constant-stress-crossection form. Also suggests directions for future concepts.

Keywords: Mooncable,lunar,transportation,maglev,superconductor,gliders

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file MOONCL14 THE MOONCABLE PROJECT2

By J. E. D. Cline, SSN [not shown], Sept 09, 1988

ABSTRACT:

In addition to enabling supply of large quantities of space-processed materials such as foamed-steel to Earth markets, this transportation system concept would have the added benefit of making available enormous amounts of cheaply transported lunar material for building radiation-shielded manned exploration spacecraft, O'Neil L-5 type space colonies, and Solar Powered Satellites. The space transportation concept being focused upon here is that of a specific form of transportation that is actually powered by the transport process in one direction, that from the lunar surface to a point dominated by the Earth's gravitational field about 5/6 the way up the Earth's gravitational well. A tensile structure extends from L-1 (the balance point between Earth and Moon) both toward the Moon and the Earth; the lunar side anchors on the Moon's surface while the earthside dangles its weight far enough into the Earth's gravitational field to hold the lunar sideup. The tensile structure is made of lunar fiberglass of constant-stress crossection, and is robot-built by gradually increasing the girth of an emplaced seed filament. When functionally completed, energy transfers between payload mass falling down the earth side of the structure is coupled over to lift more payload mass up the lunar side of the structure via space-radiation-cooled superconductors on a magnetic-levitation track attached along the length of the structure. Payload mass is coupled to the maglev track via tractor motor-generators.

(The basics of this concept are on file with NASA, which Isubmitted for safekeeping early in 1972. In retrospect, it would have been a useful follow-up to the Apollo lunar landings, using the spare Saturn V launch vehicle to emplace the "seed" cable and soft-land the initial robot glass factory at the seed's lunar terminal. It might now be useful to revive this project as an international project utilizing the Soviet "Energia" booster to replace the now unavailable Saturn V booster. And here would be a worthy challenge for developing techniques for productive mutually benificial processes for human international interaction. Perhaps holistic concepts would be invaluable here, such as those of Organizational Psychosynthesis.)The Earth's physical makeup has so many incredible coincidences that are needed for life to exist upon it, and The Earth's moon seems an extention of those coincidences in the possible extention of Earthlife into space. The Lunar tides of earth's oceans upon her beaches has stirred tidal life onto land from the sea; now the fact that the Moon always has the same face turned toward the Earth, and its relatively large mass near the Earth, show promise of a major stepping-stone for the extension of Earthlife into space. And the Lunar terrain is a potential source for raw materials for building space colony structures, closed-ecology very-large-spacecraft for exploration/colonization beyond the Earth-Moon system, and for exotic construction materials for use here on Earth such as foamed-nickle-iron-steel.

Space transport systems are necessary to transfer material and energy from where it is now, over to where it will be needed. Theoretically there are alternatives to the traditional reaction engine propelled vehicles which use energy stored in propellants. The energy differentials in space are another source of transportation energy.

Picture the Earth and Moon as being two adjacent depressions in a gravitational field. The Earth's depression is much deeper than that of the Moon's, so it is imaginable that material might be "siphoned" from the shallower depression into the deeper one. Basically this means that energy given up by payload mass falling down Earth's gravitational well is used to perform the work of lifting up more payload mass from the Moon up toward the Earth, thus forming a regenerative energy loop, self-sustaining, as is a siphon, so long as the output end's at a lower gravitational energy level than is the input end. Could an electromechanical analogy of a siphon be constructed to move raw materials from the Lunar surface over to a somewhat deeper level in the adjacent Earth's gravitational well, using the energy differential itself to power the process?

The work involved in getting out of the Moon's gravitational well to L-1 is only about 800 watt-hours per kilogram; and going from L-1 to Earth requires each kilogram to give up about 16,000 watt-hours of energy, so there is plenty of energy to tap off for use in lifting mass up from the Moon to L-1. Of course, most of the 16.5 KwHr/Kg must be dissapated in the atmospheric entry process after the payload leaves the end of the end of the "siphon". With the end of the siphon-like electromechanical transport system extending deeper into Earth's gravitational well, surplus energy is produced which could be used to lift some of the payload up only to L-1, and leave from there with relative ease toward other parts of space near the Earth-Moon system.L-4, L-5, Mars and the asteroid belt, here we come!

[Calculation reference point: the work performed in lifting all the way out of a planet's gravitational well is the same as lifting out of a well which is one planet radius deep,with a constant accelleration the same as found on the planet's surface (reference Arthur C. Clarke's "TheExploration of Space" p.33), or

Work = G*M*m*(integral from 1 to infinity)1/(R**2) dR

As a hobby, by the end of 1971 I had worked out just such aconceptual system; then there were extra Saturn 5 Moonrockets available from the Apollo flights that werecancelled, and they could be used to emplace the "seed"electromechanical transport system. I called it the Mooncable Project. It would be a profitmaking enterprisethrough the sale of space-environment processed materialsoriginating on the Moon, processed and fabricated at L-1,and delivered for sale to Earth markets. Space explorationwould henceforth pay for itself!

(Digression:But the reality was that NASA was at that time starving forfunds just for the Space Shuttle project to be startedsoon; and anyway NASA was prohibited by charter fromfinancially supporting profit-making enterprises...so said aletter to me from NASA's Inventions and Contributions Boardon June 23, 1972. With no income from my efforts, my wifesoon divoriced me, and it became appearant that myadvertising of the Mooncable Project had attracted the wrongkind of attention: I soon lost my house too and then myjob...mere survival became my focus of attention from thenon.)

The foundation analogy for this concept is that a siphon candraw water out of an aquarium without using a pump, anddoes it a lot easier than dipping it out by hand....The key is to find a way to transfer the energy from thedecending mass over to lift the rising mass. One way mightbe to transfer energy electrically through superconductorslinking the two masses; the superconductors could be part ofa frictionless magnetic-levitation railroad track laid on astrong tensile structure coupling the two masses. Couplingthe energy between payload masses would be tractormotor-generators magnetically coupled to the maglev track,pouring energy into the track while braking the fall of massdown the earthside end of the track, and consuming thatenergy by lifting more payload mass up the other side of thetrack. The Lunar surface spatial reference for thisprocess is created by a very long tensile structure anchoredon the Lunar surface and extending up through the balancepoint L-1 and over into the Earth's gravitational well. Atthe end of this document, the original calculations areshown which show that fiberglass is strong enough for thisapplication, if it is formed into a constant-stresscrossection cable. Glass is one of the most abundantmaterials found on the Lunar surface, making it ideal forbuilding this very large tensile structure.

To protect the mooncable from being accidentally severed bysmall hurtling objects, the area of the cable might best bedistributed in the form of a net or pair of hollow tubes.The conductors would be distributed for the same reason andto allow continuous power during repair activities and toallow bi-directional traffic along the cable for thereturning traction motor/generators and delivery of goodsfrom Earth.

While at the null-g balance point L-1, the Lunar ores areprocessed into useable forms. Nicle-iron, aluminum,titanium, ceramics, and glass are foamed into large molds,casting them into glider shapes for the atmospheric re-entryportion of the journey to the Earth's surface. Pockets inthose gliders hold smaller amounts of more exotic materialsprocessed in the space environment. Here at L-1, 64,000 Kmabove the Lunar surface, material is also launched outtoward other sites, such as L-4 & L-5 for building spacecolonies, for building very large spacecraft for leisurelymanned exploration of the solar system, and for buildingSolar Power Sattellite powerplants. From L-1 a space tugwould be needed to transport the material to L-5 or othersites.

CALCULATIONS TO SHOW THAT FIBERGLASS, MADE IN A VACUUM,SHAPED INTO A CONSTANT-CROSSECTION TENSILE STRUCTURE, ISSTRONG ENOUGH FOR THIS TASK:

Note that at the time this concept was completed as apersonal hobby activity, my only calculating tools were aslide rule and pen and paper. Believing that all I had todo was to show that an abundant material was capable for usein constructing the major portion of the mooncable, andthen others with adequate computers would eagerly fill inthe refinements, I set out set out to the disagreeable taskof figuring out how to calculate the forces andconfiguration of the Mooncable. Making some outside limitobservations by seeing the "big picture", I could moreeasily show that fiberglass was strong enough for a relatedbut even more demanding structure. The weight of themooncable essentially is the same on either side of thebalance L-1 point, even though the mass on either sidewouldn't necessarily be the same due to the varyinggravitational fields it crossed. So the structure just fromone side, the Lunar side, was calculated; and it was easierto calculate from the Moon's surface out to infinity than toL-1, which I did not then want to calculate its location.My old college calculus books did not seem to have anyapplicable equations for integrating through varyinggravitational fields., but I did find relevant equations inGeorge Gamow's book "Gravity": the total work of lifting anobject from R0 to some radius R, is the area under the curverepresenting the force of attraction:

Work = integral from R0 to R of (GMm)/R2) dr

= G*M*m*integral R0 to R (1/R2)dr

The integral of 1/r2 is -1/r: in general,

integral Rexp n dR = - (R exp (n+1))/(n+1), from Handbook of

Chemistry and Physics. Thus the work "W" done is

W = - (GMm)/R - (-(GMm)/R0)

W = GMm(1/R0 - 1/R)

A constant-crossection glass cable extending from the surface of the Moon and going an infinite distance away (ignoring the presence of Earth and other bodies), would experience a supporting tensile force at its far end of :

F = m*a

F = m*(1/68g)*integral from 1R to infinite R of 1/r2 dr

F = m*(1/6)*g*((1/1*R)-(1/infinite R)

F = m*(1/6)*g*(1/R)*(1/12 - 1/ infinity)

F = (1/6)*g*m/R

Now m/R is the mass of a length of one radius, and making the area equal to 1 square inch to make the results in engineering terms,

m = area * length * density

m = (1 in2)*(6.85 E7 inches)*(8.3 E-2 lbm/in3)

m = 5.68 E6 lbm

Returning to F = (1/6)*g*(m/R)/in2

F = (1/6)*g*5.68 E6 lbm/in2

F = 9.4 E5 lbf/in2

Since glass fiber cable has a strength of 5 E5 lbf/in2, it is only half strong enough for this configuration. It probably can be made strong enough, however, by controlling its cross-sectional area, with an optimum

distribution of area with distance being that which creates a constant stress within all parts of the cable's volume.

My personal ability to manipulate the concepts of calculus confidently is too weak for me to write and solve the equations required to exactly derive the cable's dimensions for a given set of loads. However, I can show that a glass cable can be sufficiently strong by integration through summation of sections of cable, each section having the same maximum stress, that stress being in a cross-sectional area great enough to support the weight of that section with its loads plus the force applied at its lower end supporting the weight below it.

The characteristics of each section are derived as follows; assuming each section has a constant cross-sectional area throughout its length:

The weight of cable in each section is

Fs = A*d*R* integral i/r2 dr

where Fs = weight of this section of cable

A = cross-sectional area of this section of cable

d = density of glass = 8.3E-2 lbm/in3

R + radius length of Moon = 6.85 E7 inches

The stress at the top of each section is the greatest stress

anywhere in the section, and with a safeth factor of two is

2.5 E5 lbf/in2. This stress is equal to the force on the

cross-section divided by the area of the cross-section:

S = (Fs + Fl)/A

where S = stress at top pf the section = 2.5 E5 lbf/in2

Fl = attached load (bottom weight + conductor etc)

A = cross-sectional area of cable section

Expanded, this equation becomes

S = ((A*d*R*integral 1/r^2 dR)+Fl)/A

Solving for Area A:

A = Fl/(S-d*R*integral 1/r^2 dR

The force at the secion top then is

F = A*S = (Fl*S)/(S-d*R*integral 1/r^2 dR, or

Fn+1 = (Fn*S)/(S-d*R*(1/6)*g integral 1/r^2 dR

The force, F, then becomes part of the attached load, Fl, of the next cable secion above it.

To make an example Mooncable calculation, some values will be somewhat arbitrarily assigned:

maximum upward pull on the Moon's surface by the cable and its loads is to be 35,000 lbf

superconducting maglev track will be equal in mass to two #12 copper wires, resulting in a mass of 2.2 E5 lbm per lunar radius.

the maximum force due to the live load will be 1 E4 lbf

This would be something less than 6 E4 lbm on the lunar surface; it is a dynamic load.

r2=Number of lunar radii reached at the top of the section

integral=avg accelleration along the section, in gees, g

fl=force at top end of section, in pounds, lbf

sectnarea= area of cable crossection, in square inches

A home computer program for calculating this follows. As it only calculates from the Lunar surface out to 10000 lunar radii, ignoring the influence of the Earth, orbital velocity, or that of the Sun, it'spurpose here is only to show that space-rated glass fiber is indeed strong enough for this task. And the lunar surface has an abundance of glass!

9000REM mooncable project cable calc, lunar influence

only,88I08 JEDCline

9010REM data list of radii

9020DATA 1.1,1.2,1.3,1.4,1.5,1.7,1.9,2.2,2.4,2.7,3

9030DATA 3.3,3.6,4.0,4.5,5.0,6,7,9,12,17,25,10000

9060 condrad=22000:REM conductors mass per lunar radius

length in lbm

9061REM condrad= conductor wt per lunar radius

9065REM conductor's weight=(2.2E5

lbm/radius)*accelleration integral for section

9070 stress=250000:REM stress in lbf/in2, max working

stress in glass fiber made and used in vacuum

9075 fl=35000:REM lbf pull on lunar surface, includes 2.5E4

lbf bias pull plus 1E4 live load

9080 density=.083:REM density of glass in lbm/in3

9090 r1=68500000:REM radius of Moon in inches

9100 r0=1

9150? "calc# radii accel. intgrl top force area"

9200FOR calc=1 TO 23

9210READ r2

9220 integral=(1/6)*((1/r0)-(1/r2))

9221REM accel. integral across change in radius from

center of Moon

9250 force=((fl+(condrad*integral))*stress)/(stress-

(density*r1*integral))

9270 sectnarea=force/stress:REM cross-sectional area atop

section

9300? calc, r2, integral, force, sectnarea

9330 fl=force:REM becomes bottom load for next higher

section

9350 r0=r2:REM top of section becomes bottom of next higher

section

9360NEXT calc

9400END

radii integrl fl sectnarea

lunar g lbf inches^2

1.0 3.5E4 1.4E-1

1.1 1.52E-2 5.39E4 2.16E-1

1.2 1.26E-2 7.60E4 3.04E-1

1.3 1.07E-2 1.01E5 4.03E-1

1.4 9.16E-3 1.27E5 5.10E-1

1.5 7.93E-3 1.56E5 6.23E-1

1.7 1.31E-2 2.22E5 8.88E-1

1.9 1.03E-2 2.90E5 1.16

2.2 1.20E-2 3.99E5 1.60

2.4 6.31E-3 4.66E5 1.87

2.7 7.71E-3 5.66E5 2.26

3.0 6.17E-3 6.59E5 2.63

3.3 5.05E-3 7.44E5 2.98

3.6 4.21E-3 8.23E5 3.29

4.0 4.63E-3 9.20E5 3.68

4.5 4.63E-3 1.03E6 4.11

5.0 3.70E-3 1.12E6 4.49

6.0 5.56E-3 1.29E6 5.14

7.0 3.97E-3 1.41E6 5.65

9.0 5.29E-3 1.61E6 6.42

12 4.63E-3 1.80E6 7.18

17 4.08E-3 1.98E6 7.92

25 3.14E-3 2.13E6 8.53

1E4 6.65E-3 2.51E6 10.05

Dividing the cable up into 23 sections, summing the forcesatop each section, reaches a value of 10 square inches at10000 radii, a realistic number. This shows that fiberglasscable does indeed have an adequate strength/mass ratio to dothe job. Since the calculations were "outsideapproximations" the area would be less than this figure;also the attraction of the Earth on the cable, and thecentrifugal orbital force on the cable would affect the fullparameter calculations. For example, the mooncable wouldreach a maximum thickness where it passes through theballance point, L-1, and thereafter decreases in girth asit extends in the direction of Earth.

Note that when engineering something, the accuracy ofcalculations is directly important. But during theformative stages of a concept, utilizing the conceptualsynthesis abilities of the right-hemisphere of the brain,accuracy of calculations is only conditionally important.

When the Mooncable calculations were originally done,plotting the curve of the cross-sectional area vs. distancefrom the Moon showed obvious calculation error; yet sincethe direction of error was to indicate that it would requireeven more glass crossectional area that would in reality beneeded, the weeks of tedious slide rule calculations werenot repeated. The goal was reached anyway, it was thought,since all that was needed to be proven was that glass fiberwas indeed strong enough to support a structure extendingfrom the Lunar surface up through L-1 and on 1/6 the wayinto Earth's gravitational well. Others with IBM 360computers, or even with the new HP-35 pocket calculators,could more easily and accurately refine the calculations...

This concept proposes an energy balancing mechanism betweendecending payload mass and lifted payload mass, primarilyuseful for transporting huge quantities of lunar materialsfor Earth markets and for construction in the Earth-Moonsystem. The payloads destined for Earth Markets is castinto foamed material gliders for the atmospheric portion ofthe trip. It would function in the unique gravitationalgeometry existing in the gravitational saddle between Earthand her Moon. It would use a combination of adaptations ofcontemporary magnetic-levitation rail transit technology.

Calculations have been presented here to show that anabundant material on the lunar surface is sufficientlystrong enough to support a fiberglass Mooncable out toinfinity, and thus surely strong enough for the lesser taskof reaching a maximum stress at the balance point, L-1.

The specific concept presented here is intended primarilyfor bringing Lunar and null-g vacuum environment commercialproducts to Earth at potentially very low expense on along-term, high-mass payload, continuous operation basis. Itshould also be useable to supply the materials forconstructing powersats (SPS), and the help supply materialsfor building colonies at L-4 & L-5 and large mannedspacecraft for the further exploration of space.

The general concept presented here is intended to arouse thereaders' creative imagination toward seeking alternativepaths for bringing mankind and other Earthlife into nearbyextra-terrestrial space.

In retrospect, this would have been an ideal follow-on tothe Apollo program, which was winding down at the time theMooncable Project was proposed (informally) to NASA. Itwould have utilized the two extra Saturn V launch vehiclesalready built, provided stimulus to reactivate the Saturn Vassembly line, provide just enough challenge to technologyto make it interesting, and would have provided constructionmaterials in space by the time the space shuttle became operational. The potential for providing competitive massive supplies of building materials for sale even here on Earth...is an unheard-of thought even now in space activist circles.

What went wrong? Why didn't the Mooncable Project get accepted? Perhaps we can learn from the mistakes of the past.... Perhaps it was that NASA was too sunk in the gloom of seeing its own finances so cut back to see, in the Mooncable Project, potentials for utilizing lunar resources, the chance to rekindle America's excitement for the space adventure. Perhaps it was that NASA, functioning under its integrity charter of not supporting potentially profit-making space enterprises, had no understanding of the author's extremely naive concept of the politics involved and non-existent salesmanship skills. The author believed that "Invent a better mousetrap and the world will beat a path to your door!"

Now there are more appropriate concepts for the leading edge of space efforts. The US no longer has the ability to produce Saturn V launch vehicles, and is unlikely to form an alliance with the Soviets to utilize their new "Energya" equivalent booster. More importantly, there have been several even more exciting space transportation concepts conceived since the Mooncable Project's time: concepts for Earth-to-space transportation, of immense proportions and implications, utilizing maglev support structures that utilize forms of stored energy for support, bypassing the weakness of the inadequate materials strength for Earth-surface-to space centrifugally-supported structures. For example the concepts (with rather flippant names) known as "Starbridge" (by R. Hyde) and "Texas and Universe Railroad" (Earl Smith , Lofstrom concept). And there are others. These concepts seem largely unknown to the public at present, although they have been available to the public, and NASA, at least since 1984. I suspect that their authors are also amazed (as was the Mooncable concept's author was in 1972) at public apathy toward the incredible futures for humanity that the concepts make possible.The huge payloads moveable by these megaprojects pave the way for true massive space colonization, in settings that are as Earthlike as possible, in this generation.

What can be done now? Perhaps the public, and even NASA, needs to have the imagination provided for them in clear detail... instead of assuming auto-evocation of the possibilities of each concept by each reader.

James Edward David Cline (GEnie J.E.D.CLINE1 or J.CLINE2) [SSN omitted here]

Van Nuys, CA September 9, 1988

An Excalator Hi page titled GeSp530 by J E D Cline started on Wednesday, April 2, 2008 3:44:33 PM US/Pacific

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