The closer Voyager came to Jupiter the more apparent it became that the scientific richness of the Jovian system was going to greatly exceed even our most optimistic expectations. The growing realization among Voyager scientists of the wealth of discovery is apparent in their comments, discussions, and reports as recounted by the authors in their descriptions of the two encounters.
Although many of the discoveries occurred in the few weeks around each encounter, they were, of course, the result of more than those few weeks of effort. In fact, planning started a decade earlier, and the Voyager team of engineers and scientists had been designing, building, and planning for the encounters for seven years. The Pioneer spacecraft made the first reconnaissance of Jupiter in 1973-1974, providing key scientific results on which Voyager could build, and discoveries from continuing ground-based observations suggested specific Voyager studies. Voyager is itself just the second phase of exploration of the Jovian system. It will be followed by the Galileo program, which will directly probe Jupiter’s atmosphere and provide long-term observations of the Jovian system from an orbiting spacecraft. In the meantime, the Voyager spacecraft will continue their journey to Saturn, and possibly Uranus and Neptune, planets even more remote from Earth and about which we know even less than we knew of Jupiter before 1979.
As is clearly illustrated in this recounting of the voyage to Jupiter, scientific endeavors are human endeavors; just as Galileo could not have foreseen the advancement in our knowledge initiated by his discoveries of the four Jovian moons in 1610, neither can we fully comprehend the scientific heritage that our exploration of space is providing future generations.
April 1980
Edward C. Stone
Voyager Project Scientist
ACKNOWLEDGEMENT
The authors are grateful to the many members of the Voyager Project team who not only made this historic mission of exploration possible but also took time from their busy schedules to offer us assistance, information, and encouragement in the preparation of this book. Among many too numerous to name individually, we particularly thank E. C. Stone, A. L. Lane, C. H. Stembridge, R. A. Mills, E. Montoya, M. A. Mitz, and B. A. Smith, L. Soderblom, and their colleagues on the Voyager Imaging Team. We are grateful to F. E. Bristow, D. L. Bane, L. J. Pieri and especially J. J. Van der Woude for their assistance in obtaining optimum versions of the photographs printed here. C. B. Pilcher and I. de Pater kindly made available their groundbased pictures of the Jovian magnetosphere. Many colleagues have read and provided helpful comments on parts of the manuscript, among them G. A. Briggs, S. A. Collins, S. Cruikshank, J. Doughty, A. L. Guin, A. L. Lane, R. A. Mills, E. Montoya, E. C. Stone, J. L. Ward, and especially C. R. Chapman.
CONTENTS
[Foreword] v [Introduction] vii [Acknowledgment] ix [Chapter 1. The Jovian System] 1 [Chapter 2. Pioneers to Jupiter] 11 [Chapter 3. The Voyager Mission] 23 [Chapter 4. Science and Scientists] 33 [Chapter 5. The Voyage to Jupiter—Getting There] 47 [Chapter 6. The First Encounter] 63 [Chapter 7. The Second Encounter: More Surprises From the “Land” of the Giant] 93 [Chapter 8. Jupiter—King of the Planets] 117 [Chapter 9. Four New Worlds] 139 [Chapter 10. Return to Jupiter] 169 [Appendix A. Pictorial Maps of the Galilean Satellites] 177 [Appendix B. Voyager Science Teams] 195 [Appendix C. Voyager Management Team] 197 [Additional Reading] 199