Abstract
Thirty years ago, Sputnik I announced to the world that the Space Age had begun. The first man-made satellite weighed a mere 184 kg and carried a single radio transmitter and its power source, which lasted for 21 days. In the intervening years enormous advances have been made in the size and power of satellites placed in orbit, in manned operations in space, in rendezvous and docking in space, and in the analysis and utilisation of observations of the Earth from space. By 1985, that is, just before the tragic accident to the 'Challenger' Space Shuttle, there were about 5000 complete spacecraft in orbit. The tonnage was increasing at a rate of about 100 tonnes per year, with a predicted growth rate of 5 to 7 per cent, that is, doubling every 10 to 15 years. The one area in which no significant advance was made during this period was in the economics of space operations. Most satellites were, and still are, put into orbit by large, expensive, unreliable and expendable rockets. Even the Shuttle with its reusable Orbiter component is very expensive to operate.
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