Although no new materials or fundamental technology is
required, the engineering challenges of building the first space cable
are formidable. Fortunately, it is possible to build small-scale
prototypes before making a full-scale commitment.
Among the principal areas for research and advanced development are:
- Wind management and stabilization, particularly coping with
buffeting cross winds: The theoretical work shown on this web site (see
Winds) and elsewhere needs to be validated in working prototypes.
- Failure scenarios: Exhaustive reviews and testing will be
needed (see Failure Scenarios).
Laboratory validation is needed, followed by field trials at
Ideally a first application will be away from the public for
such applications as communications, astronomy and the testing of
ramjets and scramjets.
The space cable has multiple pairs of tubes; five pairs are
proposed in most of the preferred designs. This gives redundancy in
tube pair fails or has to be taken out of service. The following
scenarios require further study, and there may be others:
- Ejection of bolts: If there is a breakage, high-speed bolts
will move through the atmosphere and burn up. Clearly, this would be
very hazardous for anyone near and in the line of fire.
- Loss of vacuum in the tubes: This is readily detectable
because it will cause a drop in bolt speed. The space cable can
continue to operate but with loss of energy (see Vacuum).
- Attacks or collision: Fixed infrastructure is susceptible
to terrorist action or to acts of war, mainly at the lower altitudes.
This will be a serious concern. To reduce risks, passenger vehicles
will be designed so that they can glide back to earth in an emergency.