One contrast is the difference between KESTS to GEO and the anchored tether Space Elevator concept. Most obvious is that the anchored tether is a linear structure extending from the ground up through GEO and beyond, supported by a counterweight beyond GEO, by the centrifugal force of Earth's rotation; but the KESTS to GEO encircles the earth, as in an Orbital Transfer Trajectory ellipse from ground to GEO and back, and is supported primarily be mass circulating within that loop at velocities far above orbital transfer velocity.
Comparison between tether-type and KESTS-type earth space elevator conceptual design attributes
Means of support of structure's weight:
Tether: Tensile strength of carbon nanotube ribbon matrix.
Strength to weight ratio critical to usability of material. Brad Edward's material has density of 1300kg/m3 and tensile working strength of 100 GPa.
KESTS: Kinetic energy stored within structure.
Armature mass stream velocity to mass ratio, and ratio of velocity to orbital velocity ratio, critical to balance of weight of structure
Delivery of lift energy to elevator/rail vehicles along structure:
Techniques for emplacing "seed" structure for "bootstrap" construction
Techniques for bootstrap construction
See also prsntn3
: 2005 Space & Engineering conference slides on Characteristics of KESTS Space Escalator Carousel vs. Anchored Tether Space Elevators
Another contrast is the likely futures without the capability of KESTS to GEO, or possibly the tether space elevator to some extent.
Potential futures without KESTS to GEO are almost certain to happen, sad to say, based on the responses I've found happening while I have been presenting to the public the best designs I can create for KESTS to GEO over the past 16 years spanning since 1988. If we had begun KESTS to GEO when I first proposed the concept in 1988, there would surely be some built by now, at least prototype ones, already providing some economical electrical access to GEO, yet the reality test is that people did not do it!
There are gloomy websites devoted to futures, all apparently unaware of existence of KESTS to GEO's potentials to rescue our futures. They focus on the sudden collapse of industrial civilization when oil peaks production and begins a rapid decline; CO2 accumulation Greenhouse Effect causing massive climate change and flooding of coastal cities; starvation and pestilence going rampant again; the Implosion of Civilization.
Not being quite that pessimistic, the factors most influential are:
1) public's blaise belief everything is fine, no big problem lurks;
2) relatively inexpensive abundant energy from fossil petrochemicals used for fuels increasingly are used for industrialization of the countries upon which the oil reserves exist, less to be sold to other countries, and increasingly speed the depletion of economically recoverable oil reserves, while also increasing the CO2 load on the environment so the the greenhouse effects increase;
3) continued accumulation of industrial civilization's toxic waste materials which nature can't recycle, increasingly poison the world's ecosystem including nutritional sources and drinking water;
4) focus blame on "overpopulation" institutes forcible reproduction control, as always likely to benefit the few; does nothing for the toxic materials problem of modern man's civilization; a reduced population would likely still drive their gargantuan tough SUV's to work and use unrecyclable computers and TV's, for example.
5) sudden collapse of any of these systems could cause cascade failures of the other systems already weakened, causing massive "die-off" of living systems including human. Whether some pockets of agrarian people survive depends largely on how sick we have made the ecosystem through all that.
Here is a blog entry I wrote on 20060720-21, on http://www.kestsgeojedc.blogspot.com/, describing the current state of this effort:
Civilization can go up, or likely will go down: Space Day 2006
Civilization must go up, or most likely it will go down. Are you in on this?
Sustainable living systems, including renewable energy sources and sustainable agricultural practices, are of high importance for R&D now. Yet for the long run, going up for vaster resources is likely the key for really long term sustainability of industrial civilization.
Reaction engine transportation needs to start and end its kind of journeys up high, such as in Geostationary Earth Orbit, instead of from the ground. The concepts and technological principles already exist for efficient ground to GEO electrically powered transportation, but the will of the corporations who could physically make it happen, have not the will to do it, instead being committed to stockholder quick profit while caring not if their actions do not make a place for the stockholder's children to live well... that is not on their shift, not their problem, they think.
The tendency of so many people to focus on strife to grab as much as possible, in aggregate has rapidly bent civilization into a downward curve, although headed upward until about half a decade ago.
My efforts to reverse this increasingly massive downturn continues, but the effort is about as likely as trying to stop the Lemming's excited race to the lethal cliffs over the seaside, to relieve the population to the small few sustainable by the as-found ecosystem. In fact, right now it seems as impossible for me to stop and get the herd to turn around to constructive usefulness, as much as if I were trying to stop a stampeding herd of wild elephants in the jungle. Yet the saying goes, "you gotta have a dream, for if you don't have a dream,, how ya gonna have a dream come true?.
So here in my Space Day 2006 blog entry, i intend to both explore the disruptive factors, as well as the positive potential technologies involved in the raising of civilization up, as an overall view in context with the circumstances found currently and in the past.
As for the disruptive factors, their descriptions fit better into analogs of the animal world, than of the rational intelligent loving beings that human beings are supposed to be, getting things done harmoniously together. The phenomenon of "crab potting" is one such descriptive analog. Crab potting is that if one is gathering crabs along the seashore for dinner, if you dig a hole in the sand and put one crab in the hole, the crab will quickly get out and escape. But if you put two crabs in that hole in the sand, they will prevent each other from escaping, and they will remain available for your dinner. There seems to be a lot of "crab potting" type thing going on which has been preventing us from quickly and efficiently getting civilization up. The details of how it expressed in hampering my efforts, and probably efforts of a few others too, involve egos of academic and industrial pomp protecting their turf, and use of setups and frameups for character assassination of someone they see as out of line and has seen too much and can't keep his mouth shut.
As for the technological principles that can get civilization to really expand up in an adequately large scale way, it starts with the wonderful rockets, so exciting and spectacular, with which we are familiar, like in Apollo and the Space Shuttle. They have enabled us to prove we can reach space and live there awhile, and do constructive work and research up there. Reaction engined launch vehicles, or rockets, also show us severe limits of their potential usage.
The use of reaction engine technology transportation ground to orbit has been long perfected, with multi-stage, strap-on boosters too, have shown the range of payloads manageable at a profit, and projects which orbit go beyond this limit won't get done.
Significant progress in reducing cost of launch, such as use of unmanned "big dumb boosters" is worthy of effort. Yet the basic problem of lifting the fuel for the trip, is a basic limiting factor for this kind of space access, and sets severe limits for the projects create-able up there to advance civilization, mere outposts at best.
The Solar Power Satellite is one such example, which was proposed in 1960's, and still not feasible to be put up using reaction engined launch technology. There has been some renewed thinking re gossamer-thin SPS, however.
Many other projects only possible in GEO are not amenable to the "gossamer-thin" technology construction, such as the passively shielded 10,000-person each Stanford Torus type self-sustaining cities in space, originally designed for construction at L5 out of Lunar materials, homes for those people building SPS; but also constructable in GEO if using passive shielding that is environmentally friendly such as wood fiber reinforced ice. They require truly large scale economical lift of materials ground to GEO; so, "thinking our of the box" (the "box" being reaction engined space access, in this case) the context is atmospheric resistive winds and weather, the energy and materials expended during the lift to 22,300 miles above the equator and give orbital velocity horizontal push there, for materials to stay put up there. The good news is that the actual energy given to mass lifted from ground to GEO is small, less than $1 of electrical energy per pound mass payload lifted into GEO. Lots of things can be done at anywhere near that figure, including SPS.
Although trips from ground to space up until now have been done using action-reaction engine propelled spacecraft's detailed intricacies, there are a couple of potential very different ways to get from ground to high earth orbit. It would be wise to evaluate and R&D them to the max at the present time, while also pursuing the other paths for mankind, especially the more environmentally friendly technologies as our basis if we remain chained to the ground on into the far future, as we are headed now, unfortunately.
Although I continue to dabble in the anchored tether space elevator conceptual design aspects which began (as so many others did too back then all independently) starting circa 1969 in my case, not quite the first. Lots of potential there, and widely different configurations highly dependent on the actual obtainable strength to mass ratio of the tether material.
However, in more recent years (1988 - on) I've focused on a technique that would avoid the need for superstrength tether materials and beamed or lifted energy sources for moving elevator cars up and down the tether.
Yet, to my amazement, intelligent people don't seem to grasp the "KESTS to GEO", or "Carousel Space Escalator to GEO" conceptual basics; they are fairly simple yet very un-ordinary. And that is the problem in communication of the concept, I think: it is un-ordinary.
Although I don't have nearly the mental abilities of people like O'Neill and Clarke, I do have much the same general overall visions; and I have persistence and integration skills, and much practical experience in making electronic gadget designs into reality that work on the physical level, into manufacturable products, while employed as an electronics engineering technician for decades in complex fields: a high competence in taking a design vision and making it work for real.
So let me again explain something that is un-ordinary, yet each part is simple. Let's start with the thought of a "hoop", the round thing that is the outer part of a wheel.
Actually several concentric hoops, sliding around the circumference of the overall hoop. And we will eventually make the hoop as an electric motor shaped as a hoop, with motionless stator and rotating armatures; but for now lets look at the dynamics of a hoop that is spinning, That spinning causes centrifugal force on the hoop, pressing its parts outward away from its center of rotation. We are going to use this principle of outward centrifugal force to balance an externally imposed inward force. Let's make that hoop be huge, say a hoop that fills an entire low earth orbital circumference above the earth's equator.
Sure, it's big; but not nearly so big as the length of all the beverage cans we make and use each year, which if put end to end would reach back and forth from ground to the moon and back several times, a far greater size.
Nonetheless, it is an un-ordinary visualization, a hoop that is so big it is larger than the planet's circumference of 24,000 miles. If the hoop is spinning at the orbital velocity at that altitude, all parts of it are "in orbit", staying there for now. Its outward centrifugal force just exactly balances the inward force of the earth's gravitational field on the mass of the hoop's parts. This is plain old normal orbital mechanics, except really a lot of orbiting objects all in the same path. it could have an enormous mass, yet would stay high above the earth, supported by its outward centrifugal force created by its rotation; and it rotates around the Earth. Is this agreeable to you, so far?
We next need to manipulate this concept for supporting mass above the earth, to ultimately become a transportation structure between ground and orbital altitude, preferably as high as Geostationary Earth orbit, stationary relative to the earth's surface in its 24 day's rotation. To make it a ground to GEO shape, change it for now from a circular orbit to an elliptical orbit which has its low point in contact with the earth's surface at the equator, and elliptically encircling the planet to reach to GEO above the far side of the earth.
The hoop is actually three hoop types sliding around closely together, remember. One hoop section is not rotating relative to the earth, and is solidly anchored into the earth somewhere along the equator, such as in a tunnel in the Ecuadorean Andes mountain range.
The second hoop is rotating far faster than orbital velocity, so the surplus outward centrifugal force balances the weight of the aforementioned stationary hoop with its loads; this speedy hoop needs be made of discontinuous parts as they exchange kinetic and potential energy as they rise and fall relative to the earth. And those discontinuous masses are in the form of armature segments with permanent magnets embedded, thus the armature of our hoop-shaped electric motor.
At the earth surface ground connection site (eg, that tunnel in Andes mountains) electrical energy from outward sources (for now) is used to accelerate the armature segments as they whizz past, restoring the kinetic energy that was used up in their trip around the planet-encircling hoop structure.
And the third "hoop" is also generally discontinuous, being the aggregate of the captive spacecraft being lifted by inductive drag against the high velocity upward bound armature segments, lifting the spacecraft up from the ground to GEO, where they discharge their payload, and take on new space-resource cargo for the gentle efficient return to the ground along the structure.
The stationary part of the hoop also provides a hard vacuum environment for the high velocity armature segments where the structure is within the atmosphere.
And the armature segments are in counter-rotating paired mass streams, laterally coupled through the stationary part of the structure, to balance some gyroscopic precession forces, and to provide upward bound armature mass streams everywhere along the structure.
The sliding hoops need to have a very slippery, low-loss sliding surface nature, thus a special variety of magnetic levitation track technology needs to be developed, one that works in a hard vacuum at tens of kilometers per second relative velocities; lots of potential for electromagnetic induction there going up as the cube of the velocity, usable for induced magnetic levitation principles.
The armature mass streams can be arranged around inside the stationary part of the hoop, and differential electrodynamic drag between the sides of the armature mass streams would provide a small bending force, usable for servopositioning in response to varying lateral loads including from atmospheric wind forces.
Hopefully this description gets the reader past the problem of the "un-ordinary" and give a glimpse of how such a transportation structure can extend between ground and GEO, supported by the kinetic energy stored within itself. If you are interested, many details have already been worked out and most are on my websites and in my papers published as part of ASCE space conference proceedings in 2000, 2002 and 2004.
And the things such a transportation structure can enable built in GEO are incredible, expanding civilization up there, and making efficient reaching out from GEO instead of the ground, to the materials resources of the solar system from there via reaction engined powered spacecraft, bringing back construction materials from the Moon and asteroids, for starters. Building Mars colonies would be a quite different adventure, and far more likely to succeed, with such a background, is another example.
Building many huge SPS in GEO could provide the environmentally friendly electric power delivered to nations around the world, beginning the reduction of CO2 greenhouse effect problems; giant solar powered mass-spectrometer type element separators in GEO could be total recycling for toxic idustrial waste products; Stanford Torus design inspired cities in GEO could be built and occupied by vast numbers of people in artificial gravity comfort.
Isn't this a better goal for humanity, instead of continuing the warring at each other for rights to dwindling resources of a world we have been surely killing? Sure, we know how to make war far better than know how to make these space structures; and making war is so exciting! That is, unless oneself is among the bystanders that get mangled while the behemoths are grappling.
Can we set aside the egos of academic and industrial pomp protecting their turf, and use of setups and frameups for character assassination of someone they see as out of place, and has seen too much and can't keep his mouth shut?
Actually, the creation and use of the Carousel Space Escalator and its enabled applications in GEO, is likely to provide excitement and adventure galore, if we give it a solid chance. And thus provide a much healthier world and civilization to pass on to our progeny.
And the upcoming problem of having enough assignable energy for huge manned spacecraft launches in a world starving for energy, gets avoided when SPS built in GEO beam down solar-derived electric power to the structure's ground accelerator site, thus ensuring continued access to space, regardless of the availability of conventional energy resources thereafter.
And, this is happening on our shift. Can we turn our vision away from the addiction to strife's glories of upsmanship, and instead settle down to responsible and equally exciting but far more comfortable life works, such as the vision described here? Civilization must go up, or most likely it will go down. Are you in on this?
This is a "work in progress," doing my best for the vision.
Copyright © 2005 James E. D. Cline