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Space Elevator
Post: #1

Experts agree that the biggest drain of energy takes place when a vehicle blasts off, pushing through Earth?s gravitational pull requires great amounts of fuel, but once they get out of our atmosphere, the rest is easy.

If you could cut out that ?blast off? portion, space travel would be easier and much more fuel-efficient.

In a Space Elevator scenario, a Maglev vehicle would zoom up the side of an exceedingly tall structure and end up at a transfer point where they?d then board a craft to the Moon, Mars, or any other distant destination.

If it all sounds like too much science fiction, take a look at the requirements for making the Space Elevator a reality. A new material has been developed, however, called carbon nanotubes, that is 100 times as strong as steel but with only a fraction of the weight.

A carbon nanotube is an idea that makes this all sound much more achievable.

In this concept, which is very fuel efficient and which brings space tourism closer common man uses the newly added concept of nanotubes to light.
Post: #2
Currently all space agencies are completely dependent on rockets to get into space. space elevator can provide the high-volume, low-cost transportation system that will be required for the future space activities mankind hopes for. A system that may have the required traits , space elevator. The space elevator, a cable that can be ascended from Earth to space, is unlike any other transportation system for getting into space, its is a proposed structure designed to transport material from a celestial body's surface into space. which involve traveling along a fixed structure instead of using rocket powered space launch. The concept most often refers to a structure that reaches from the surface of the Earth on or near the Equator to geostationary orbit (GSO) and a counter-mass beyond. Recent conceptualizations for a space elevator are notable in their plans to use carbon nanotube or boron nitride nanotubebased materials as the tensile element in the tether design
[Image: space_elevator01.jpg]
[Image: SpaceElevator2.jpg]
[Image: space-elevator.jpg]

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Post: #3
Space Elevator

Chris Biedrzycki
Ned Cameron
Mike Gruener
Erick Haro

What is a Carbon Nanotube?

Can be thought of as a sheet of graphite (a hexagonal lattice of carbon) rolled into a cylinder.

Why CNTs?

Young's modulus is over 1 Tera Pascal
Strength 100x that of steel at 1/6 the weight (estimated tensile strength is 200 Giga Pascal)

Chemical Vapor Deposition

• Involves heating a catalyst material to high temperatures in a tube furnace and flowing hydrocarbon gas through the tube reactor
• The materials are grown over the catalyst and are collected when the system is cooled to room temperature
• Key parameters are:
– Hydrocarbons
– Catalysts
– Growth Temperature
• CVD process involves the dissociation of hydrocarbon molecules catalyzed by the transition metal, and the dissolution and saturation of carbon atoms in the metal nanoparticle
• Both MWNT and SWNT can be grown by CVD methods
– MWNTs use acetylene gas for the carbon source and a growth temperature between 600 – 800°C
– SWNTs use carbon monoxide or methane for a carbon source and a much higher growth temperature (900 –1200°C)
Post: #4

Experts agree that the biggest drain of energy takes place when a vehicle blasts off, pushing through Earth’s gravitational pull requires great amounts of fuel, but once they get out of our atmosphere, the rest is easy. If you could cut out that “blast off” portion, space travel would be easier and much more fuel-efficient. We have seen the different concepts involved for the success of this idea. If this concept comes to light soon, its going to prove very fuel efficient and going to be very cost effective. Here we look into the various advantages and disadvantages involved. We also take the Economical point of view also into consideration.



1. Introduction 1
2. Challenges Faced By Space Elevator 2
3. Different Concepts 3
4. Design considerations 8
5. Advantages 14
6. Disadvantages 15
7. Economics 17
8. Conclusion 18



The story of Jack and the Beanstalk is starting to sound more and more plausible every day. A huge, tall structure comes out of the ground and goes straight up through the clouds; at the end is a wonderful, mysterious castle. Experts agree that the biggest drain of energy takes place when a vehicle blasts off, pushing through Earth’s gravitational pull requires great amounts of fuel, but once they get out of our atmosphere, the rest is easy. If you could cut out that “blast off” portion, space travel would be easier and much more fuel-efficient. In a Space Elevator scenario, a Maglev vehicle would zoom up the side of an exceedingly tall structure and end up at a transfer point where they’d then board a craft to the Moon, Mars, or any other distant destination. If it all sounds like too much science fiction, take a look at the requirements for making the Space Elevator a reality. A new material has been developed, however, called carbon nanotubes, that is 100 times as strong as steel but with only a fraction of the weight. A carbon nanotube is an idea that makes this all sound much more achievable.

In this concept, which is very fuel efficient and which brings space tourism closer common man uses the newly added concept of nanotubes to light.



The major challenges faced for bringing this concept to light are

2.1 Atmospheric issues

Lightening, clouds, winds. Historic data maps shows lightening occurs a land masses ,less on mountains and least along equator, further experimental cables don’t attract lightening ,winds aren’t a factor since it is capable of withstanding wind spend of 71m/hr and hurricanes not a problem since they form and travel outside the equatorial region.

2.2 Impact or Collision

Big issues requiring more study .Debris is monitored using radar. Stud between Debris and meteors indicate space debris to be more hazardous .It must be noted number of impacts on ribbon, not as important as degradation cost due to impact.

2.3 Health issues

Fiber health focuses on three things, dose, dimension and durability .The bigger ones can’t be integrated and smaller ones appear to dissolve quickly.




The LEO space elevator is an intermediate version of the Earth surface to GEO space elevator concept, and appears to be feasible today using existing high-strength materials and space technology. It works by placing the system's midpoint station, and center of gravity, in a relatively low-Earth orbit and extending one cable down so that it points toward the center of the Earth and a second cable up so that it points away from the Earth. The bottom end of the lower cable hangs down to just above the Earth's atmosphere such that a future space plane flying up from the Earth's surface would require 2.5 km/sec less change in velocity than a single-stage-to-orbit (SSTO) vehicle launched directly to LEO. The space plane and LEO space elevator combination would likely be able to carry 10 to 12 times the payload as an equivalent-sized SSTO launch vehicle without the LEO space elevator. The length of the upper cable is chosen so that its endpoint is traveling at slightly less than Earth escape velocity for its altitude. This is done so that a spacecraft headed for higher orbit, the Moon, or beyond, can be placed in the proper orbit with only minimal use of its onboard propellant.

LEO Space Elevator concept

The overall length of a LEO space elevator from the bottom end of its lower cable to the top end of its upper cable is anywhere from 2,000 to 4,000 km, depending on the amount of launch vehicle velocity reduction desired. It should be possible to launch a LEO space elevator in segments using existing launch systems. Once on orbit the LEO space elevator would then use its own onboard propulsion system to raise itself to the necessary orbital altitude while reeling out the upward and downward pointing cables as it went. Another advantage of this system is that as the market expands and materials improve, it could continue to grow in length and diameter, further reducing launch velocity and increasing system payload capacity. It even appears possible to grow the LEO space elevator into the full-length, 35,000-km-plus space segment length of the Earth surface to GEO space elevator if that were desired. The fact that it is a freely orbiting system and not attached to the Earth at its lower end allows the system to be placed in an inclined orbit aligned with the plane of the ecliptic. This has advantages for traveling to the Moon and other planets as it would avoid plane change maneuvers and would greatly increase the number of launch windows for a given timeframe. Another advantage of the inclined orbital plane is that if a resonant orbit is used, the lower end of the system will pass within range of most of the world's major airports twice a day on a fixed schedule. Once the velocity required to reach the lower end of the LEO space elevator is down to the Mach 16 range or less, horizontal takeoff and landing space planes operating out of those airports appear to become both technically and feasible economically feasible.

3.2 Lunar Space Elevator Concepts

Another near-term application of the space elevator concept could be demonstrated at the Moon. The one-sixth gravity at the Moon makes it theoretically possible to construct tethered connections from the surface of the Moon to the LaGrange libration points L1 and L2, on the near and far side, respectively, using existing materials (Kevlar, Spectra, or PBO graphite epoxy).

It has been envisioned that on the near side of the Moon such a structure could become the transportation system for moving materials to L1 in support of solar-powered satellite construction and propellant storage platforms. The regolith located at the base of the elevator contains oxygen which could be extracted. Additional gases from ice deposits at the lunar poles might also be transported around the Moon to this point for transfer to L1. At L1, solar-powered satellites would become part of a space utility system for production and transfer of power to the surface of the Moon and other stations within the Earth/Moon system. Likewise, a propellant platform at L1 would act as a service station for reusable in-space transportation vehicles.
On the far side of the Moon at L2, a similar system could be envisioned for lunar and space infrastructure support. On the surface of the far side of the Moon, ideas have been proposed for large space observatories, and as a remote location for the long-term storage of hazardous materials like the nuclear waste generated on Earth that must be stored safely for thousands of years.

Earth Orbiting and Lunar Space Elevator concepts

3.3 Mars Space Elevator Concepts

At Mars, proposals have been studied for tethered elevator type structures in a low-Mars orbit, and extended from the two moons in orbit around the planet, Phobos and Deimos. Both moons are in the same orbital plane around Mars at near equatorial inclinations. Tether structures extended toward and away from Mars on each of these moons have been shown to provide a means of payload transfer to and away from Mars that would significantly reduce propellant requirements.
The material strength required for a system like this appears to be within the limits of current technology. In one possible design, a Kevlar tether is used to transfer a 20,000-kg payload from a low-Mars orbit to a Mars-Earth transfer orbit. Such a system in orbit around Mars could be one way to establish a permanent transportation infrastructure for ongoing exploration and development of the Mars system.

Mars Space Elevator Transportation System



SE Construction

The initial construction would require a spacecraft/ satellite which would be powered by rockets (or possibly laser beaming) to reach low earth orbit and second-stage rockets to achieve geosynchronous orbit. On the craft would be one-micron-thick ribbon wrapped on a spool. Once geosynchronous orbit has been achieved, the craft would deploy the ribbon down through the earth's atmosphere to a movable, anchor station. The craft will then "float" outward with the end of the 110,000-kilometer ribbon to become the counterweight. The ribbon would be tapered to 13.5 centimeters diameter at earth surface to 35.5 centimeters at geosynchronous orbit. Lightweight climbers would then ascend the ribbon to attach additional ribbon strands to increase the ribbon to a thickness capable of supporting a 20-ton climber with a 13-ton payload. This stage should take two years and about 230 trips. The trips will probably take about one week each. These lightweight climbers would then be used as additional counterweights. The climbers will be powered by a large laser directed by a specially designed mirror to the photovoltaic cells on the bottom of the climber. The energy would be converted to electricity. In time, other heavier ribbons could be deployed so that stations, manned craft and, yes, even hotels can be constructed. With a whole ribbon system, space travel to other planets via the SE could be accomplished. Ironically, Mars or the Asteroid Belt would be the easiest travel to initiate while the earths own Moon would be one of the hardest.

4.1 CNT Research and Development

Much of this first conference was devoted to the current status of the CNT research. Bottom line is that the necessary breakthrough to actually bonding the carbon nanotubes into a composite material and thence into a structure like a ribbon hasn't happened yet. One of the purposes of the convention was to draw together many of those working on the CNT to compare notes.

Nanotubes are from one to 1.7 nanometers wide. They come in different lengths and as open or closed ended, single-walled, double-walled or multi-walled. Their tensile strength is 100 times stronger than steel at one-fifth the weight. Current production processes include electric arc, chemical vapor deposition, pulsed-arc discharge and pulsed laser ablation. Single-walled nanotubes would be best for structural purposes since the composite material can be adhered to each separate nanotube. With the multi-walled nanotubes, the inner tubes cannot be reached for bonding.

The key breakthrough for use in the SE is adequate dispersion. Nanotubes tend to grow in bundles (ropes) which make it difficult to harness their capabilities. In addition, their crystallization properties make them strong but difficult to manipulate. Currently, no solvent has been found that can disperse the bundles into individual nanotubes.

Mathieu Grac of Nanoledge S.A. in France noted that Nanoledge has produced CNT composite fiber but the purity is only 50%. Andrews added that UK has produced a polymer fiber, CNT composite but with only 1% doping. The SE needs 80%. He also mentioned that multi-walled nanotubes are easier to work with. Li Feng from the Chinese Academy of Sciences discussed the hydrogen arc discharge method for single-walled nanotubes. Excitement increased as the teams realized they were working on different parts of the same project, resulting in brainstorming sessions. However, Roylance predicted at least five years before the CNT could be commercially viable.

Once the CNT breakthrough has occurred, the nanotubes can be dispersed and placed into a composite material. After running through conventional textile processing to align a set number of fibers in a parallel configuration, the fibers would be spooled. The ribbon construction and design itself would consist of the many individual fibers loosely connected with thousands of the 10-micron fibers with cross connections across the ribbon at intervals of 10 centimeters or more in a tape sandwich process. The individual ribbons would then be spooled. The entire process would be automated.

4.2 An Alternative Ribbon Design

Robert Hoyt of Tethers Unlimited has designed a space tether system called Hoytetherª with funding from NIAC. The tether has straight fibers under tension running the length of the cable and cross diagonal fibers to distribute load. One advantage of this system for the SE is that it minimizes meteor damage. Hoyt showed an actual simulation of a tether payload system with a cost around US$2.5 billion. Although NASA considers the tether system mainly a design for space itself, it could be adapted to the earth-to-space-to-earth elevator concept.

4.3 Anchor station

A number of decisions regarding the location of the anchor and power-beaming stations have already been made. They will most likely be placed 2,000 miles west of Ecuador, 2,500 miles south of San Diego and 1,500 miles southwest of Acapulco, Mexico. According to historical data weather maps, the Pacific equator area has relatively tranquil seas, no known lightning strikes and no hurricane has ever passed the equator. Plans call for an anchor station with a 46,000-ton mass at 133 meters by seven meters and a top speed of 12 knots. The power-beaming station will need at least a 13-meter segment mirror and a 350kw electronic laser. The anchor platform could be adapted from the Sea Launchª program within 18 months.

Adapting that technology for the SE would cost around US$300-500 million. Günther Migeotte of Art Anderson Associates in Brementon, Washington added that requirements for the anchor platform in the Pacific Ocean would include interchangeable parts, 100 staff personnel, one kilometer per day movement and a stability of five degrees in roll. The anchor station must also consider weather conditions with a 72-hour to one-week preparatory time. Art Anderson Associates has offered to build a customized anchor station for around the same amount as it would cost to adapt the Sea Launch platform. In the Q&A session, adapting an oil tanker was suggested. The biggest issue with a tanker is the motion susceptibility.

4.4 Tower Alternative

According to Geoffrey A. Landis from the NASA John H. Glenn Research Center in Cleveland, launch could be accomplished by a 15-kilometer tower since altitude is not as important as velocity. The biggest advantage to the tower concept is the increase in payload mass. The Q&A session brought up such issues as what type of material could the tower be built from, how much of the tower square footage would be needed for the SE equipment, can the tower support the weight of the equipment, where to build, costs (which was not available) and buckling issues.



1. Economical
2. Space tourism
3. Future exams in space
4. Manned exploration in mars and colonization
5. Large orbiting solar collectors for power generation and transmission to Earth
6. Inexpensive delivery of satellites to space satellites



Dangers faced

6.1 Micro meteors

These are small meteors in space that may crash into the strong but deterioratable cable connection..

6.2 Lightening

This pose a great threat for the success of this idea, since this is a natural phenomenon it can’t be controlled.

6.3 Wind

U can b never control wind speed, this also natural phenomenon, we can predict how fast the wind is moving but we can’t control it.

6.4 Induced oscillations

This occurs when load or payload is moving up and down the carbon nanotube

6.5 Radiation

The radiations from the sun can cause serious problem, there is a chance the continuous exposure to the Sun may burn the cable.



With a space elevator, materials could be send into orbit at a fraction of the current cost. Modern rocketry gives prices that are on the order of thousands of US dollars per kg for transfer to low earth orbit and roughly 20 thousand per kg of US dollars per kg for transfer to geosynchronous orbit .For a space elevator the price could be on the order r of a few hundred of dollars per kg.Space elevator have high capital cost but low operating expenses, so they make the most economic sense in a situation where it would be used over a long period of time to handle very large amount of payloads. The current launch market may not be large enough to make a compelling case for a space elevator ,but a dramatic drop in the process of launching material to orbit would likely result in new types of space activities becoming economically feasible. In this regard they share similarities with other transportation infrastructure projects such as highways or railroads.

Development cost might be roughly equivalent, in modern dollars, to cost of developing the shuttle system .A question subject to speculation is whether a spec elevator would return the investment, or if it would be more beneficial to instead spend the money on developing rocketry further.



So now we have come to see the great advantage this concept has to our lives .Once we stop laughing about the concept has to our lives. Once we stop laughing about the concept and give it a thought then there are changes that it may come up pretty soon else it can take ages .We can think of going for a tour with our Childs or lately with our grandchildren, send gifts to our relatives who have settles out in the moon etc..So we have to give some serious thought to this idea and make this idea a revolutionary one.


• Aurthur C Clarke –“The Fountain Of Paradise”
• Edward B C – “The Space Elevator :A revolutionary Earth to Space
• Space Elevator-Institute for Scientific Research
Post: #5
Presented by:
Thomas Rand-Nash

The Space Elevator
The History
1960: Artsutanov, a Russian scientist first
suggests the concept in a technical journal
1966-1975: Isaacs and Pearson calculate specifics
of what would be required
1979: Authur Clarke, in Fountains of Paradise
describes a long filament lowered from
geosynchronous orbit, and used to hoist
objects from the surface
1999: Nasa holds first workshop on space
2001: Bradley Edwards receives NAIC funding
for Phase I space elevator mock-up
Why Build It?

$$$: Space Shuttle Missions cost an average of $500,000,000 or $7,440/lb.
The projected 10 yr cost of the elevator is $40B (est. 500 missions)
Future “missions” require no propellant, the major cost of rocket missions
Riding on a continuous and giant explosion is extraordinarily dangerous, as is re-entry (Challenger, Columbia).
No human risk, missions are unmanned.
How Could It Be Done?
The Components
The Ribbon
The Anchors
The Climbers
The Power
The Ribbon: Design
The Ribbon: Construction
Initial production takes place on earth
Aligned nanotubes are epoxyed into sheets, which are then combined (reinforced)
Climbers have a similar system on-board to build tether
Why Carbon Nanotubes?
The Chiral Vector R = na1 + ma2, (where a1 , a2 are the primitive lattice vectors and n,m are integers) with wrapping angle  connects atoms at A and B. The length of R is the circumference of the nanotube, and is created as A is rolled into B. The direction of the resulting tube axis vector will be perpendicular to R.
Possible structures of nanotubes can be formed corresponding to wrapping angles 0≤≤30, (n,m) m≤n.
The values of n and m determine the chirality, or "twist" of the nanotube. The chirality in turn affects the conductance of the nanotube, it's density, lattice structure and therefore, mechanical properties.
a) “Transverse” strain finds a natural release in a bond rotation of 90° for the armchair tube, thereby elongating the tube and releasing excess strain energy. Defect is formed, which leads to non-elastic behavior
b) “Longitudinal” strain induces a 60° rotation in the zig-zag tube. Less tube elongation therefore more resistant to defect formation
Inelastic behavior
Measuring Tensile Strength

CNT’s are connected to the SEM tip via either “nano-welding” or Van der Waal bonding
Individual CNT’s are stretched until breakage, or deformed to determine elasticity
Tensile Strength/Young’s Modulus
Values for Y were obtained by linear-fit to the stress/strain data points
Y ranged from 320-1470TPa
Strength values range from 13-52GPa (vs. 63GPa needed for elevator)
Tubes undergo abrupt shape shift under stress, emitting phonons, or crunching. These correspond to singularities in the stress/strain curves
Tubes bounce back from stress to reform original shape
Hole Propagation
Tiny imperfections in ordinary materials amplify stress locally.
As load is applied, these amplifiers pull and break apart the adjacent chemical bonds
In nanotubes, the coupling between tubes is very weak (VdW).
Therefore, a break in one tube doesn’t affect surrounding tube, and hole propagation ends
The Anchors
The space anchor will consist of the spent launch vehicle
The Earth anchor will consist of a mobile sea platform 1500 miles from the Galapagos islands
The Climbers
Initial ~200 climbers used to build nano-ribbon
Later used as launch vehicles for payloads from 20,000- 1,000,000 kg, at velocities up to 200km/hr
Climbers powered by electron laser & photovoltaic cells, with power requirements of 1.4-120MW
The Power
Free-electron lasers used to deliver power
Adaptive Optics on Hobby-Eberly telescope used to focus Earth-based beams, (25cm spot @ 1,000km altitude)
Reduced power delivered at high altitudes compensated by reduced gravitational force on climber, (~0.1g)
Major Hurdles
Ribbon Construction
High Winds
Atomic Oxygen
Low orbit object
Ribbon Breakage
Sufficient Ribbons
Nanotubes must be defect free and straight
The epoxy must be strong yet flexible, burn up at a several hundred Kelvin, and cure relatively quickly
The length of the finished cable is 91,000km, and nanotubes are cm in length
Large scale behavior of nanotubes unknown
Nanotubes are grown aligned, and defects can be controlled in current production methods, (spark gap)
The ribbon can be produced in small length bundles and then connected
Atmospheric Oxygen 60-100km
Extremely corrosive, will etch ribbon epoxy and possibly nanotubes
Coat ribbon with Gold or Aluminum which have resisted etching in these atmospheric conditions,
(NASA’s Long Duration Exposure Facility)
Low Orbit Objects 500-1700km
108,000 (>1cm) objects with enough velocity to sever or critically damage tether. Strikes could occur ~every 14 hours
Tracking systems for objects >10cm already in place, sea platform will move tether to avoid
Tracking systems for 1-10cm objects coming on-line
Pretty obvious
Va der Waal forces between nanotubes limit the damaged area
Low meteor flux, & small probability of large (>1cm) impacts
Climbers will be capable of repairing ribbon continuously
Ribbon has lower resistivity than surrounding air, lighting will prefer this path.
Platform lies in a region of very low lightning activity
Platform is mobile, and can move tether out of the way of incoming storms
High Winds
32m/s wind velocity will induce enough drag to destroy tether
Winds at platform location consistently below critical velocity
Width of tether will be adjusted to minimize wind loading
The Future
As of 2004, carbon nanotubes are more expensive than gold. Future supply increase will lower this price
Technology to “spin” Van der Waal bonded nano-yarn has begun.
Edwards completed Phase II planning in 2004, with funding from NASA’s institute for advanced concepts
However, many properties of nanotubes still remain to be tested, frictional, collisional, etc.
Third Space Elevator Conference is held to discuss advances on the concept
Fully operational elevator could be built within 15 years.
Some Parting Words..
David Smitherman of NASA/Marshall's Advanced Projects Office has compiled plans for such an elevator that could turn science fiction into reality. His publication, "Space Elevators: An Advanced Earth-Space Infrastructure for the New Millennium", is based on findings from a space infrastructure conference held at the Marshall Space Flight Center last year. The workshop included scientists and engineers from government and industry representing various fields such as structures, space tethers, materials, and Earth/space environments."This is no longer science fiction," said Smitherman. "We came out of the workshop saying, 'We may very well be able to do this.'"

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