Introduction

High above the earth, sitting in a stationary orbit, a vast array of solar panels, fifty square kilometers in size, receives continual sunlight.  Capturing this solar energy far more efficiently than any earth-based mechanism, it converts this inexhaustible energy supply into microwave energy, and beams it down to a large collector in the Arizona desert.  This system supplies 400GW of power, meeting 80% of the United States energy needs in a cheap, plentiful source with negligible environmental impacts. Although sounding futuristic, this scenario (the Solar Power Station – SPS) has been comprehensively investigated by NASA and others.  It is a viable long-term solution (there is nothing particular complex or technically insurmountable about it) to the impending fossil fuel crisis, and would potentially be one of the greatest impacts in human development.

Currently, however, the only means of getting anything in to space is with chemical rockets.  This situation presents two key obstacles stand in the way of projects like the SPS:

1. the very large cost of getting things into space (such a solar array would weigh in the order of xxx tons)
2. the limitation on the size (both mass and dimensions) of objects that can be transported via rockets[i]

Cost justification for the NASA proposal required a cost per kg for payload launch in the order of $100.  Presently, the cheapest rates are in the order of $4,500/kg, and for larger launch capacities, closer to $15,000/kg.  The maximum payload capacity is around 20 tons, and the maximum dimensions 18x13.  Using current (and any foreseeable) rocket technology would require several thousand trips, and a cost of in excess of  1 trillion dollars. But such an idea does not have to shelved just yet.  An alternative mechanism for moving large masses into space has been proposed.  Termed the Space Elevator, it takes an almost childlike idea, and marries it with cutting edge materials and aerospace technology, opening up possibilities for the exploitation of space that have previously been the realms of science fiction.  This report will outline the space elevator concept, and the potential it has to permanently change the nature of space exploration.

Another way up

Ask a child how they would get somewhere high, and they would say build a tower.  There is a certain appeal of the obviousness to this solution[ii], but its downfall is that as the tower gets higher its mass increases, and eventually gravity will win, with the lower sections unable to support the mass above it.  Tapering (like a mountain) can offset this effect, but finite limits exist – and the human capacity for mountain construction is fairly limited. To address the mass issue, we could use lighter building materials, and if our aim is simply to reach some high point, a piece of string might do the trick.  As the string rises higher and higher[iii], the gravitational pull gets smaller and smaller, and gravity/mass becomes less of an issue.  With a strong, light material, such a ‘string to space’ could be created. However, the earth is rotating, so the string is actually being hurtled out in to space (via Newton’s first law), with only Earth’s gravity preventing this from happening.  As the string gets higher, it is spinning more quickly, and therefore pulling away from the earth with greater force.  At a certain point, the centrifugal effects outwards will be greater than the gravitational pull downwards, and rather than the bottom of the string holding up a heavy weight, it will be holding onto a mass pulled away from the earth.  As the centrifugal force is a product of mass[iv], the longer the string (and the greater the mass) the more force it has to pull against. To prevent the string from breaking, it must be very strong, or reinforced with more string (increasing mass).  Using steel wire, one the stronger materials available , the mass required to prevent the string from breaking reached nearly infinite proportions as the length increased, and the concept of a ‘string to space’ was buried.

Carbon Nanotubes

When scientists discovered a new form of carbon in 1985[v]– a hollow spherical molecular not unlike a soccer ball (and termed a ‘buckyball’) – a new world of materials was opened.  Scientists have produced a vast number of structures using buckyballs, including tubular arrangements, termed nanotubes, 1-1.7 nm in width, with bucky ball hemispheres as endings. In addition to their curiosity value, carbon nanotubes have several extraordinary properties.  They have a tensile strength 100 times that of steel, with only 1/5^th the weight.  This is the highest strength rating of any known substance[vi].  Their structure also makes them impervious to most other chemicals, making them highly durable.  Lengths of up to 20cm have been produced. Those who had examined the Space Elevator concept to less glorious conclusions in the past realised that carbon nanotubes had the properties needed to perform the role of the ‘string’.  With a theoretical maximum tensile strength of 300 Gpa (giga pascals), against the calculated requirement of 100-150 Gpa for the space elevator, carbon nanotubes are the essential breakthrough to make the concept viable. Rather than a string (or more accurately, a rope), there are a number of practical reasons (related to surviving various environmental hazards, deploying the string and general operations) to favour a structure whose dimensions (thickness and width) are significantly different – a ribbon structure.  The ribbon must aim to minimise weight (via its thinness), but maximise strength (via its width).  The proposed design has thousands of small diameter fibers (10 microns thick) with cross connectors at intervals of 10cm or more.  The short lengths of the fibers (20cm lengths have been produced) means they would have to be incorporated into a composite, but tests have shown that the tensile strengths required are achievable[vii]. For the space elevator to be viable, it must stay upright – passing through the same theoretical point above the earth at all times.  If we were to place a satellite in such a position, we would say that it is in Geosynchronous Earth Orbit (GEO) – always above the same point.  We are therefore aiming to have the ribbon in GEO, which requires its center of gravity to be in GEO.  This can achieved by varying the length of the ribbon, and the weight distribution.  If the ribbon ended at GEO (an altitude of 35,785km), it would require an infinite mass at this point to have a GEO center of gravity.  As the string gets longer, the mass required (usually by way of a counter-weight) is reduced, up to a maximum length of 150,000km, where only the ribbon’s mass is the counterweight. The centrifugal forces acting on the ribbon mean that it must increase in mass as it extends, to ensure sufficient tensile strength.  A taper ratio of 1.364 has been calculated as a workable parameter for system design. This gives a proposed ribbon length of 100,000km. Once the technical problems of constructing the ribbon are solved, then additional problems assume a more mundane status.  Vehicles (called ‘climbers’) can travel up and down the ribbon at any speed they wish (the requirements of escape velocity being no longer required).  Having determined that such a structure is theoretically possible, we should now examine some reasons why we would want to build it.

Why build the space elevator

The space elevator would offer the following possibilities:

Place heavy payloads into orbit

The payload capacities of the Space Elevator scale with the size of the ribbon, meaning present mass barriers[viii] , and size limitations can be overcome.  The hundreds of launches needed for the components of the International Space Station could be dramatically reduced, and other spacecraft previously dismissed would become feasible.

Place fragile payloads into orbit

Without the need for sudden, violent acceleration, much more fragile structures can be placed into space – such as large optical telescopes.

Send large payloads to other planets

Beyond GEO, the rotational velocity imparted on a released object allows earths gravity to be escaped, and provides a low fuel, low cost mechanism for interplanetary travel, dramatically expanding the previously limited ambitions in this field.

Return heavy and fragile payloads back to earth

Returning objects (such as broken satellites) from space is very difficult, and the primary mechanism – the Space Shuttle, has finite mass and dimension limitations.  The Space Elevator will make returning objects (including manufactured goods and raw materials from space) common place[ix].

Deliver payloads much more cheaply

90-99% cost reductions over rocket technology are achievable.  Of all capabilities, this is the most significant, as it will act as a huge stimulus to human commercial entry into space

Rapid delivery and return of payloads

Initial launch schedules could provide 24 launches a year, compared with the 6-8 previously achieved with the space shuttle.  More elaborate configurations would see several departures a day.

Survive problems and failures and be repaired

The non-mechanical, inert nature of the ribbon means that damage can be readily repaired, reducing risk considerably.

The Space Elevator Concept

The next section outlines the various operational issues of the Space Elevator proposal, and the challenges these solutions address.

Ribbon deployment

Despite our tower analogy, it is not feasible to deploy the ribbon upwards, and so the ribbon must be launched into space, and sent down to earth.  We are therefore still limited by existing launch mechanism parameters when performing our initial deployment.  The initial ribbon and deployment craft are too heavy to launch as a single unit[x], and must be launched as multiple units to lower earth orbit (LEO – about 300km in this instance) and assembled in-space, then boosted into GEO.  The fuel requirement of moving such a large spacecraft in GEO, and then out to a distance of 100,000km to act as a counterweight are enormous – conventional fuels would weigh 145 tons.[xi] Studies have shown that the ribbon must be placed into space in one piece (it is not feasible to construct or join the ribbon in space).  This mean that the mass of the initial ribbon is limited by current launch capabilities – around 22 tons[xii].  This is nowhere near the mass required for a practical system (we will use a 20 ton capacity ribbon as the initial target).  However, providing an initial ribbon can be deployed, small climbers can traverse the ribbon, adding additional ribbon material, and increasing the strength.  The mass of the additional ribbon will be determined by the carrying capacity of the ribbon, and will grow as the ribbon gets larger. Because of weight and other technology issues[xiii], Magneto-Plasma-Dynamos (MPD) propulsion is recommended for achieving GEO.  This laboratory developed technology would require refinement and development, but the costs are not much greater than the 7-8 launches and orbital assembly challenges of the chemical rocket powered scenario.  The mass saving on fuel allows two ribbon spools to be deployed – instantly doubling ribbon capacity. MPD allows specific thrust of up to 4000 ISP.  It accelerates ions (from a variety of fuels[xiv]) at high speeds (40,000m/s) to achieve propulsion, but unlike ion engines, uses high current rather than high voltage.  This allows larger engines to be built, increasing thrust, Isp and working life[xv].  An 800kw engine (as proposed) would shift the deployment vehicle from LEO to GEO in 138 days, using 9.3 tons of fuel.  This is 14 times less than the fuel mass for a chemical rocket transfer.  The long flight time is a small price to pay for such economies. The downside of MPD system is the large (heavy!) engines required to produce the current.  However, power beaming technologies that would be applied to the climbers (see below) are envisaged as a viable solution in this case, allowing technology reuse and negating the headache of designing and deploying a 1Mw nuclear reactor into space. Deployment will see the ribbon unspolled towards its earth-based anchor location.  At the same time, the deployment craft will move outwards, balancing the center of gravity at GEO.  To initiate the process, a small “endmass” craft will be used to guide the ribbon earthwards[xvi] as there is no initial force pulling the ribbon away from the spindle.  The endmass craft will provide the ribbon with the appropriate angular momentum, with earth’s gravity[xvii] acting as a stabiliser once 2km or so of ribbon is unspooled.  To achieve this, we must release the ribbon at the right velocity and at the right angle to the vertical. The endmass craft will also act as a location beacon on descent, and detect the number of rotations (which are unavoidable due to the lack of tension on the ribbon) that take place, (allowing the ribbons to be correctly untwisted[xviii]). The deployment craft has an estimated mass of 83 tons.

Climbers

These machines will traverse up and down the ribbon, and are the most important component of the system after the ribbon. Initially climbers will have the sole purpose of adding additional ribbon strands to the main ribbon, increasing its weight bearing capabilities.  As discussed, the ratio of ribbon to climber mass is 1.364:1.  As the ribbon increases in width, and therefore support capacity, the mass of the climber (and its ribbon payload) will increase, meaning that more and more ribbon can be added faster[xix].  Initial ribbon attachment will focus on extending the width, until it is able to adequately survive micrometeor impacts.  Then, thickening of the ribbon will be performed.  The final width is envisaged to be in the order of 1 metre. The initially deployed ribbon capacity will be 990kg, of which 520kg will be ribbon, and 380kg will be climber.  The first climber will ‘zip’ the two deployed ribbons together.  After completing their ribbon run, the climbers will move to the end of the ribbon and act as a counter weight (hence the importance of the 1:1.364 climber to ribbon ratio). Tensile strength and gravitational force are the limits upon how much weight the ribbon can support.  Once a climber reaches 0.1g[xx], another climber can start its ascent – a period of roughly 119 hours, reducing with time down to 71 hours[xxi].  Using these figures, a 20 ton capacity ribbon could be built in 2.5 years, whilst a 200 ton capacity ribbon would take 4 years.  Advances in power per kilogram for engine design would improve these figures.  One advantage for speedy construction (beyond the obvious of being able to use the Space Elevator sooner) is that the time that the ribbon is susceptible to potentially ‘fatal’ incidents (primarily meteor strike) is reduced, reducing overall project risk. The ribbon deployment and attachment mechanism will need to be able to operate at high speed (200km/hr), with exceptionally high reliability and without damaging existing ribbon structure. Locomotion requirements of the climbers include:

• large quantity energy output (up to megawatts)
• high efficiency
• high power to mass ratio
• operation in both air and vacuum environments
• long (up to months) fail safe operation
• operate in constant power/variable speed mode[xxii]
• operate with torque and rpm ratios greater than 10:1

Because of the compelling requirement for an external power source, much of the climber will be devoted to the mechanisms for capturing and converting the energy source.  A 4m diameter photoelectric cell capture grid on the underside of the climber is proposed, although others have suggested that by placing the cells on the side, non-localised energy sources could be utilised[xxiii].

Power Beaming

Several alternatives to power the climbers have been proposed.  However nearly all present insurmountable difficulties.  Running current up the wires (despite carbon nanotubes being excellent conductors) would use uneconomical amounts of power, whilst nuclear engines would be too large for all but the biggest of climbers (although in the distant future of 200 ton capacity ribbons these may become an option). Power beaming involves sending electromagnetic energy in a tightly focused beam to a receiver.  The receiver uses the captured energy to trigger a photoelectric process to produce power.  The proposed mechanism for the Space Elevator is to use laser beaming. The key obstacle to this mechanism is the distortion of the laser beam by atmospheric elements at sea level[xxiv].  However, the distortion can be overcome using a technique called Adaptive Optics, which is used in telescopes to remove atmospheric distortion.  Such techniques allow precision focusing of the laser at distances of 10,000km and beyond[xxv].  Expansions of existing designs and prototypes would enable the production of a 1 Mw laser.  A 20 ton climber would require about 2.4Mw, so an array of three such units, with interlaced pulses would be constructed[xxvi]. The photovoltaic cells proposed use gallium arsenide, and achieve a power density of 540 kW/m2[xxvii].  A small climber with a 4m diameter base requires about 8 kW/m2, so the cells are more than up to the task.  Laser would not be able to breach clouds, so the anchor location would need to be in a fairly cloudless location. The use of microwave waveforms has been proposed, but requires a much larger beaming device, and the absorption of high frequency microwaves by water vapour would present serious obstacles.  As previously mentioned, this power system can also be used to drive the MPD for moving the deployment structure to GEO.

Anchor location

Once the deployed ribbon reaches the earth, it needs to be anchored.  Once this is done we have a permanent connection that we can ‘climb’ into space, and the days of the limits of chemical rockets are behind us.  However, running a 100,000km ribbon into space is not without its difficulties, which we will discuss shortly.  In summary, the locational requirements for the anchor point are as follows:

• away from lightening
• away from cyclones and other storm activity
• near the power beaming source
• having available room to maneuver the ribbon away from potential hazards
• readily accessible
• near the equator

Although a land based anchor point is not impossible (and there are a number of benefits to be gained from locating the anchor on a mountain), there are a number of compelling reasons for a sea-based location.

• mobility – the anchor can easily be moved to avoid storms and can reposition the ribbon to avoid low-orbit objects
• sea based platforms are proven technology (e.g. oil rigs)
• no high-altitude issues such as snow, limited access and low temperatures
• shipping large objects by boat is commonplace

A specific locale in the Pacific ocean, 1500km west of the Galapagos Islands, has been selected as optimal, with the following additional benefits:

• storms, lightening strikes, cloudy days are very rare
• it is located in international waters[xxviii]
• in the event of a breakage, human and environmental impact is limited

However, a sea based platform has several disadvantages, including:

• lateral movement affecting ribbon tension – this will need to be offset by motion compensation systems
• uncoordinated movement of anchor and power beaming platforms – the motion compensation systems will need to be synchronised
• salt corrosion
• significant distance from major service facilities

Challenges

Despite the simplicity and elegance of the Space Elevator concept, the fact remains that a lightweight thin cable 100,000km long is a fairly tenuous structure on which to base the entire space going future of this planet upon.  A single complete sever in the ribbon would instantly destroy the concept, with virtually no salvageable components (apart from the land based facilities).  And there are many potential threats to the ribbon that must be mitigated to prevent the project becoming a very expensive folly.  The key risks that have been identified, and their mitigation strategies are outlined below:

Lightning

Although carbon nanotubes have a high melting point (6000°c), a sufficiently powerful strike could melt a large enough section to weaken and possibly sever the ribbon.  Avoiding lightening prone areas, and moving out of the path of electrical storms is a low-tech solution, but readily achievable from a sea based platform.

Meteors

Although referred to as empty, the space around earth is teeming with dust and other objects, with frequency inversely proportional to size.  Objects above 1mm in diameter are very rare.  However, even minute particles travel at such high speeds that they deliver high energy damage on collision. The key to dealing with these impacts in a non-fatal way is to increase the width of the ribbon as quickly as possible.  A meteor striking the ribbon head-on will impart the greatest amount of energy, but over the smallest area.  As the angle of impact increases, the area affected increases, but the energy levels (and damage) decrease.  A suitably wide ribbon can successfully absorb all but the largest of collisions (although ongoing repair is still needed to ensure long term ribbon viability).

LEO Objects

Although it might be encouraging to note over 8,000 objects (with diameters over 10cm) orbiting the earth are currently tracked, 100,000 objects between 1 and 10cm exist, and these are not tracked.  These objects exist primarily in LEO, between 500 and 1700km.  Unlike meteors, these objects continually orbit the earth, and can potentially strike the ribbon on each pass.  Calculations[xxix] put the potential frequency of a fatal strike at once every 250 days – an unacceptable level.  There are two solutions: remove the dangerous objects, or move the ribbon out of the way.  The first solution is certainly not feasible in the early life of the ribbon[xxx], and anything less than almost 100% removal only pushes the time between fatal impacts out.  The avoidance option must be factored into operations to ensure the viability of the Space Elevator.  Although not currently performed, the capability to track objects of this size does exist[xxxi], and with this information, the anchor system will be able to adjust the Space Elevator’s position to avoid these impacts .  Increasing the ribbon width in this ‘danger zone’ would also reduce the impact of collisions, and increase the size of objects needed to be tracked (and hence the viability of such a tracking program).  Because of the importance of avoiding such collisions, the costs of establishing such a monitoring program must be factored into the overall budget of the project.

Wind

A wind-speed in excess of 116 km/hr has the potential to break the ribbon.  Although the preferred location is unlikely to experience winds of this strength, some changes to the thickness to width ratio will reduce the frontal area subject to winds, increasing the ribbons tolerance.  Such dimensions are only required for the first 10km of the ribbon.

Atomic oxygen

Although existing in molecular form at ground level, individual atoms of oxygen exist at altitudes between 60 and 800km.  Atomic oxygen reacts with carbon based materials, and would most likely corrode the ribbon.  Coating the ribbon with a non-reactive substance, such as gold, platinum, silicon oxide, can greatly reduce corrosion rates (estimated at 1 micrometer a month) to negligible levels, but impacts on ribbon weight need to be considered.

Other potential threats

Concerns have been raised about the influence of the earth’s electromagnetic field and radiation belts.  However, studies have shown that the localised effects of these fields are so small as to be well within the tolerable limits of the ribbon.

Costs

Total estimated costs for the project are $6.085 billion, with a 30% contingency[xxxii].  See Appendix A for a detailed breakdown.  This budget would deliver an operational Space Elevator with a 20 ton capacity.  Additional ribbon construction would obviously become much cheaper as existing project components would be reused, and more significantly, the Space Elevator can be used to transport all necessary components to space, drastically reducing all launch costs.  Although there is strong evidence supporting the feasibility of the Space Elevator concept, considerable time and money would still be required before a formal project initiation could be in.  Such research may take 5-10 years.  Allowing for design and component construction (particularly the ribbon), actual deployment from launch to the first trip would take 3.5 years, involving 230 climbers.

Returns

The economics of the Space Elevator are instant!  A basic 20 ton, 1 ribbon configuration allowing 24 trips a year (15 days traveling time to GEO and back), with a 13 ton payload per trip, gives an annual capacity of  312 tons.  Assuming 1 million dollars a day in operating costs[xxxiii], this gives a cost of roughly $1,150/kg to place an object in GEO.  This compares very favourable with current figures of $60,000/kg for the space shuttle, and $15,000kg for commercial rockets, so there will be no shortage of initial customers. Using multiple climbers simultaneously (taking advantage of the reduced gravity at higher altitudes) allows further inroads to be made.  However, dramatic future cost reductions are virtually built into the system. One of key advantages of the Space Elevator is that it will greatly simplify the making of other Space Elevator’s, allowing development and deployment costs to be more readily recouped.  A key drawback of a single ribbon is the lost time that occurs when climbers are returning from delivering payloads.  Although future usage of the ribbons and space would see these return journeys carrying products of space manufacturing, for the first few years at least, this would be non-productive use the ribbon capacity.  However, with a pair of ribbons, one could be used for ascending traffic, the other for descending traffic[xxxiv].  This would allow a steady flow of traffic into space, and maximise ribbon usage. Whilst larger capacity ribbons can lift previously unthinkable payloads into orbit (a 200 ton capacity ribbon could lift 120 ton payloads), these ribbons also allow a greater number of smaller climbers to be on the ribbon at anyone time – 50 ton climbers could depart every 15 hours.  This would give an annual capacity (assuming a 35 ton payload capacity) of 20,000 tons.  Depending on the extent to which scenarios are planned, costs as low as $3.00/kg[xxxv] – similar to rates for existing land and shipping transportation systems. Building a second ribbon quickly is not only an economic imperative, it is also a crucial risk management factor.  Whilst ever there is only one ribbon, the entire project is at risk from a freak meteor impact or a more mundane terrorist attack.  However, once a second Space Elevator exists, any catastrophic impact one of the ribbons will not wipe out the project, and the remaining ribbon can be used to quickly deploy a replacement ribbon.

Impacts of space elevator

It is not pure hyperbole to predict that the successful deployment of a Space Elevator mechanism could be the most significant event in the course of human history.  Opening up space to human occupancy and exploitation vastly expands our resources and horizons, and present possibly the only realistic mechanism for doing so.  Looking towards the future, some possibilities created by the Space Elevator include: The inexpensive delivery of satellites to space, at 90-99% of current costs will open the skies to far more commercial uses.  Smaller and poorer countries would be able to access space, and communications and media delivery would be transformed, with an enormous localising effect.  Global communications networks, like the failed Iridium venture, would become commonplace, and the capacity and bandwidth on the Internet (and its replacements) would reach levels that would allow real-time access to massive amounts of data anywhere in the world at a fraction of current costs. As well as satellites pointing at earth, space-based observational platforms can be far more easily deployed, and on much larger scales.  Optical telescopes dwarfing Hubble would be possible, and enormous radio telescope arrays would greatly expand out understanding of the universe, and offer potential order of magnitude increases in resolution capability. Large scale commercial manufacturing in micro gravity space would become a reality, impacting a broad range of industries, from medicine and computer component manufacture to new and emerging industries such a nanotechnology.  The concept of people working and living in space will become almost mundane (eventually), and a whole raft of support activities will develop around this. The Space Power Station concept described in the introduction could become reality within ten years of the Space Elevator’s completion – and indeed could possibly utilise its entire capacity for this period.  As it currently stands, such a proposal is the only potential long-term solution to the very real and imminent fossil fuel crisis facing the earth, that doesn’t involve massive reductions in world economic growth. Space exploration will be radically impacted.  Colonisation of the moon and Mars will be far easier to achieve with low cost capability to get massive objects into orbit, and have space-based support facilities.  With a permanent space station presence, manned moon exploration and the establishment of a permanent base are much more readily achieved, with ongoing reuse of landing vehicles.  Although there are scientific and ‘frontier’ reasons to develop a manned lunar base, the major attraction would be to ‘mine’ the volatile rich lunar regolith.  As well as vast quantities of resources that can be utilised for space activities (such as methane), the moon has substantial quantities of Helium 3, a very rare element on earth.  Helium 3 offers the strongest potential as a fusion power source – one kilogram offers the energy equivalent of 150,000 barrels of oil. Mars is particularly tantalising, as the space elevator’s faster orbital speed at altitudes beyond GEO will allow journies to this planet with minimal fuel, utilising the angular momentum to achieve earth escape velocity.  The economic impacts on proposed Mars missions of the drastic reduction in fuel requirements make such a mission much more viable.  Also, the increased mass capabilities of the Space Elevator will allow much more massive craft to be sent, addressing many of the current issues for a manned Mars mission, such as cramped quarters and high radiation exposure[xxxvi].  A larger crew and more support systems can also be taken. Looking ahead, the dynamics of the Space Elevator are equally applicable to Mars as they are on earth (although the moon’s gravity is too small to support one).  A Martian Space Elevator would allow return traffic to earth to be equally fuel efficient, setting up an ongoing exchange mechanism between the two planets[xxxvii]. Although we have capped our initial ribbon at 100,000km, a longer ribbon would allow greater escape velocities to be achieved, and would bring other planets into the low fuel destination path.  A dedicated launch ribbon could be constructed for this purpose. Moving into our local solar neighbourhood will act as a springboard to further solar exploration and explotiation.  Mining of near earth asteroid resources offers enormous quantities of raw materials that can be utilised in space based manufacturing industries[xxxviii].  The quantities of volatiles in the gas giants dwarf those on the moon, and enough He3 exists to provide fusion power for longer than the sun will continue to shine.  The resources in space dwarf those on earth to an unimaginable degree, and long-term survival of humanity (millions of years) will only be possible if those resources are tapped.

Just Do It

With recent announcements about manned Mars missions, and oil prices heading over $40 a barrel, the impetus to seek a cost effective mechanism for delivering massive payloads to space has never been greater.  By approaching the problem from a new perspective, the Space Elevator concept overcomes many of the problems that dog the rocket-based solutions, and delivers benefits far beyond simple cost and fuel savings (such as the in-built capability to return goods to earth).  Although this report has only provided a broad overview, all technical aspects of this project have been researched, and more detailed investigation continues.  Several key technologies, particularly carbon nanotubes, require further development, but the underlying fundamentals of this project of very solid, rather than optimism with a scientific veneer. With a total project cost of roughly 6 billion dollars (a small fraction of the projected budgets of the International Space Station or a manned Mars mission, or recent US military follies), and an almost instant pay-back (something no other space project has ever some close to producing), the case financial case for the Space Elevator is overwhelming.  The potential rewards to the entire world, not just the project’s stakeholders, mark this as a concept that should attract the support and priority of the made the Apollo program a reality.  It’s that important.

Appendix A

Cost estimates of the Space Elevator – Initial Deployment

Bibliography

Edwards, B. C., Westling, E. A., “The Space Elevator”, BC Edwards, 2002