Pioneer Encounters Saturn
Prior to the Pioneer 11 close approach on September 1, 1979, Saturn had never been inspected by spacecraft. Pioneer 11 instruments discovered a strong magnetic field surrounding Saturn, 500 times stronger than Earth's and aligned with the orbital axis. The planet was also found to have an internal heat source responsible for radiating more energy than it receives from the Sun.
Imaging instruments on Pioneer found that unlike Jupiter, the clouds of Saturn were very bland, with little real color variation.