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Prospects, Economics and the Environment

The 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

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.
Rain forest



Economics

The 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 Estimates

The 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.

Height
km
Length
km
Launch speed
km/sec
Payload
tonnes
Cost
US $billions

0.3
0.6
-
1
0.005
Rescue platform
20
70
0.6
90
0.6
Ramjet booster
15
45
11
0.02
1.1
Electric coil gun for unmanned vehicles
50
188
1.6
90
2.4
Launching manned upper-stage rocket or scramjet
50
145
15
0.06
3.4
Electric coil gun for unmanned vehicles
50
188
1.6
90
5.1
Solar power generator plus launching manned upper-stage rocket or scramjet
140
352
2.4
90
7.4
Launching manned upper-stage rocket
140
1050
7.9
60
24.9
Launching manned spacecraft direct to orbit
140
500
30
0.04
27.0
Solar power generator plus launching unmanned craft direct to Mars

The technical details of these versions and how the cost estimates are obtained are contained in published papers appearing in Technology.

Income Estimate

A 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 Activity

Much 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.