The Voyage of Mariner 10: Mission to Venus and Mercury

The success of Mariner 10 in attaining-and exceeding-its goals is attributable to the dedicated effort of the relatively small but exceedingly competent and highly motivated group of men and women from universities, industry, and government who made up the Mariner Venus/ Mercury 1973 project team. Mariner 10 visited Venus once and Mercury three times in a period of a little over 500 days on a voyage of more than a billion kilometers. Shortly after the spacecraft left Earth it was oriented to the Earth and the Moon and returned the first of over 8000 pictures that were taken throughout its trip. These pictures of the Earth and Moon provided a calibration for later pictures of Venus and Mercury. During the cruise from Earth to Venus, Mariner 10 acquired data about the environment of interplanetary space and obtained information about the comet Kohoutek, which passed by the Sun shortly after the launch. On February 5, 1974, after traveling 236 million kilometers, Mariner l0 skimmed past Venus within 12 kilometers of the preplanned aim point. Over 3500 pictures were obtained as the spacecraft first saw a thin crescent and then the full face of Venus. These photos revealed a global distribution of ultraviolet clouds which rotate about the planet some 50 times faster than the planet rotates on its axis. On Marcia 29, 1974, following several additional course corrections which were made after leaving Venus, the spacecraft reached its primary goal: Mercury. Man obtained for the first time brilliantly clear pictures of this planet. Mercury' looks a great deal like the Moon. However, it has a dense interior and unexpectedly possesses a weak magnctic field. Mariner's cameras also revealed surface features not previously seen on other planets. The surface of Mercury records the early history of the cataclysmic events that occurred during the formation of our solar system. The primordial state of the planet's surface, when studied in combination with similar data obtained from the Moon and Mars, should provide a great step forward in our understanding o1"the origin and ew)lution of the solar system and thus of our planet Earth.


Foreword ................................................................................................ iv
Introduction ............................................................................................ vi
Chapter 1-Earth's Sister and the Twilight Planet ........................... 1
Chapter 2-Mariner Venus-Mercury Mission ................................... 11
Chapter 3-Mariner's Payload ........................................................... 19
Chapter 4-Spacecraft, Scientists, and Schedules ........................ 29
Chapter 5-Venus Bound-Success and Near Failure ................. 45
Chapter 6-Best Seen in Black Light ............................................. 61
Chapter 7-Mercury, Moonlike and Earthlike .................................. 71
Chapter 8-Return to the Innermost Planet ................................... 89
Chapter 9-A Clearer Perspective .................................................. 101
Appendix A-Mercury Mosaics and Maps ..................................... 107
Appendix B-Processing the TV Images ...................................... 177
Appendix C-Spacecraft and Science Teams .............................. 207
Appendix D-Mariner 10 Award Recipients .................................. 213
Suggestions for Further Reading ................................................... 221
Index .................................................................................................. 225