Contrary to the reverence accorded the astronauts as space explorers, most exploration of the solar system has been done by small, ingenious, little-known robots sent as human emissaries to every planet circling our sun. Not since the last Apollo moon mission, in 1972, has a human engaged in any space exploration whatsoever. Ambassadors From Earth is a general one-volume history of these unmanned efforts to understand the universe.
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