The Pioneer 10 and 11 spacecraft, launched in 1972 and 1973,
respectively, were well named: they made the first crossings of the
asteroid belt and were the first to encounter Jupiter and its intense
radiation belts. Pioneer 11’s trajectory, bent into a hairpin curve by
Jupiter’s powerful gravitational field, allowed it to recross the solar
system to make the first flyby of Saturn almost a billion miles from
Earth where it came within 13,300 miles of the cloud tops.
Assembled in this publication is a selection of the pictures returned by
Pioneer 11 of Saturn and its largest moon, Titan. These images are of
great beauty as well as of great scientific interest, serving to whet
our appetite for the more detailed observations to be made by Voyager in
1980 and 1981. Tracking of both Pioneers will continue for many more
years, providing fundamental data on the nature of interplanetary space
in the depths of the solar system. The results of these outer-planet
Pioneer missions have far exceeded our hopes and expectations of a
decade ago when the program was initiated.
Robert A. Frosch, Administrator
National Aeronautics and Space Administration