• Moreover, as the space-faring nations deploy a diverse and cost-effective in- orbit infrastructure, Powersat-type systems are likely to be mandatory. Growth of the in-orbit infrastructure will be enabled by the availability of economically-supplied power - a situation analogous to the power stations that enabled the industrial revolution on Earth. • As current space operations are very modest, it is has been argued that the cost of developing Powersats cannot be rationalised. The example of communications satellites was studied for clarity, and it was concluded that the possible savings realised from using a Powersat would be overwhelmed by the high development and operational cost of the Powersat itself. Simply put, the cost of a power subsystem (including launch) is relatively modest when amortised over the life-time of each individual communications satellite. • However, Powersats appear economic when they enable a significant recurring cost saving over the life-time of a particular programme. In this sense, the “one-off’ savings generated from not having to build or launch a full-sized power subsystem are of less importance. • Large space stations on the scale of the International Space Station (Freedom) or a later proposed European Manned Space Infrastructure (EMSI), could provide a suitable niche market opportunity in the relatively near-future for a simple Powersat system. • The specific example of Freedom is particularly interesting. Doubling the power of Freedom using integral solar arrays approximately doubles the aerodynamic drag. As a result, this doubles the amount of propellant that must be launched every year to keep the station in orbit. For Freedom’s planned 56 kW Assembly Complete configuration with three solar array wings, about 10 tonnes of propellant, including the container, will need to be
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