Space Cable |
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Prospects, Economics and the EnvironmentThe Space Cable is a proposal with an outline feasibility
study and supporting mathematical reasoning (see published papers)
that
shows
it
can be built with today’s materials by extending known
techniques. The Environment
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Rocket launches cause a great deal of noise and pollution, whereas the Space Cable is silent apart from air noise. Since vehicles depart quite slowly when at low altitude, there will be less noise than that made by aircraft landing – much less than the noise of takeoff. An efficient design for the space cable is proposed that uses quite a small amount of energy to keep it aloft, although this is not zero; energy is consumed in the stabilization processes (see Stable Magnetic Levitation and Stabilization and Cross Winds). However, a net energy surplus could be achieved by attaching thin-film solar panels above the level of cloud and wind. By contrast, in rocket and jet propulsion, enormous quantities of energy are dissipated with the exhaust gases. Some people may object to the sight of tubes soaring into the sky; others may find the design quite elegant. It is hard to predict such matters of taste and aesthetics. |
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EconomicsThe design parameter that most affects costs is the speed of the bolts. This determines the expense on superconductors in the ambits and ramps, because their radius is proportional to the speed squared. This can be kept relatively low by having greater mass in the bolts, achieved by lengthening them. Cost EstimatesThe following estimates consider nine different versions of
the space cable, which illustrate the range of possible sizes and
configurations. The rescue platform at $5million is the smallest and is
designed to be carried on a truck and trailer. The others are all fixed
installations, with a surface station at each end either on land or
sea.
The ramjet booster could be used for supersonic airliners without the
weight and complexity of a dual turbine and ramjet mode. The electric
coil guns use the space cable as a high-altitude platform for launching
small payloads with minimal air resistance. The 50-km-high versions
seem a good compromise between cost and utility. They are high enough
for multiple uses, including astronomy, communications, tourism and
solar power generation. They replace the expensive first stage of a
rocket, and they can be used as a test platform (and eventual launch
method) for scramjet engines, wings and other components of a
hypersonic
aircraft.
The technical details of these versions and how the cost
estimates
are obtained are contained in published papers appearing in Technology. Income EstimateA single scientific instrument such as the Hubble space
telescope could pay for most, if not all, of this figure; its estimated
lifetime cost is about $6 billion. Placing a telescope on the space
cable would be more like building a ground-based observatory in terms
of cost and complexity, because it can readily be accessed for
servicing and upgrades. The Space Cable would materially improve the viability of the
proposal to combat global warming by placing a large number of shields
between the Earth and the Sun. They could be launched directly to the
required point (the Lagrange point) at quite a modest cost compared
with launching them by rockets. 1000 tourists a day would use three trips of each of five 100-seat vehicles, assuming 67% loading. If they each pay £2000 and the operating cost is £500 out of that, the annual revenue is £500 million. This turns a profit in the fifth year without counting other sources of revenue. Future ActivityMuch progress could be achieved by
building an indoor scale
model. If you are interested in supporting or participating in this
activity, please make contact (see Contacts). One challenge is to find applications small enough to be
affordable at moderate investment. Generally, small-scale applications
can usually be achieved more cheaply using conventional methods. The
advantage of using dynamics to support a structure only seem to be
apparent for very large structures. |