PIONEER SATURN ENCOUNTER
CONTENTS
FOREWORD
The Pioneer 10 and 11 spacecraft, launched in 1972 and 1973,respectively, were well named: they made the first crossings of theasteroid belt and were the first to encounter Jupiter and its intenseradiation belts. Pioneer 11’s trajectory, bent into a hairpin curve byJupiter’s powerful gravitational field, allowed it to recross the solarsystem to make the first flyby of Saturn almost a billion miles fromEarth where it came within 13,300 miles of the cloud tops.
Assembled in this publication is a selection of the picturesreturned by Pioneer 11 of Saturn and its largest moon, Titan. Theseimages are of great beauty as well as of great scientific interest, servingto whet our appetite for the more detailed observations to bemade by Voyager in 1980 and 1981. Tracking of both Pioneers willcontinue for many more years, providing fundamental data on thenature of interplanetary space in the depths of the solar system. Theresults of these outer-planet Pioneer missions have far exceeded ourhopes and expectations of a decade ago when the program wasinitiated.
Robert A. Frosch, Administrator
National Aeronautics and Space Administration
September 1979
NASA
National Aeronautics and Space Administration
Ames Research Center
Moffett Field. California 94035
Artist’s drawing of Saturn and its rings showing the Pioneer Saturn spacecraftpassing under the rings and nearing closest approach to the planet. Actual picturescould not be obtained at this time because of the high speed of thespacecraft.
INTRODUCTION
We have entered into a new era of space exploration. Missionsundertaken during the lunar exploration of the 1960’s typicallylasted a matter of days with commands issued and carried out in nearreal time. Now, a decade later, planetary voyages may last for manyyears as the spiraling trajectories of the spacecraft make periodicintersections with the orbits of the planets. Communicating with usacross the vastness of space, these spacecraft report to us their experiencesas they traverse the outer reaches of the solar system.
Among these deep space travelers, Pioneers 10 and 11 are appropriatelynamed, for they truly are pioneering the exploration of theouter solar system. Launched in 1972 and in 1973, respectively, theywere the first spacecraft to fly by Jupiter (in 1973 and 1974). AtJupiter, Pioneer 11’s trajectory was carefully tar