GRAND STRATEGY FOR EXPLORING THE PLANETS
What can be considered a grand strategy for planetary exploration began to emerge in the 1960s. It was not, of course, conceived fully developed but has evolved from NASA-sponsored groups of scientist and engineers most from universities and from the scientists composing the Committee on Planetary and Lunar Exploration of the National Academy of Sciences Space Science Board. The basic concept is that of a fourstage program, each successive stage building on its predecessor. The four stages are reconnaissance, exploration, intensive study, and exploitation (or utilization).
By reconnaissance we mean the effort to characterize a planet. The reconnaissance phase has been completed for the terrestrial planets and will be partially completed for the Jovian planets after Voyager 2 makes its close passage by Uranus and Neptune. In the exploration phase we hope to determine much more about the physical state of a planet and to derive some understanding of the physical processes that have shaped and are shaping its evolution.
The Voyager 1 and 2 flybys are very sophisticated spacecraft so that they not only have performed a reconnaissance mission but also have taken a major step toward exploration of Jupiter, Saturn, and their satellites. Pioneer Venus launched the global-characterization program for Venus. The Viking mission represents the exploration phase of Mars.
The third stage in planetary study is referred to as the intensive-study phase, which seeks "to define or refine the remaining scientific questions of the highest order that have been revealed by reconnaissance and exploration and that can be studied in depth.. These kinds of study are of course those done from onsite inspection (not necessarily manned). Only the moon and Mars have been subjected to intensive study-and this still in a limited fashion.
The final phase is probably not truly part of a scientific study. Known as exploitation, or utilization, or comprehensive understanding, this fourth phase yields scientific data as a by-product. It is a level that has been reached only for the earth although there are proposals and plans for establishing a permanent base or bases on the moon, which would include some for mining and manufacturing. Besides the moon there are no plans for exploitation of any celestial body that go beyond the talking stage.
