Pioneer 11's Saturn
Date: 1 Sep 1979
Saturn and its moon Titan are visible in this image from Pioneer 11.
Pioneer 11's path through Saturn's outer rings took it within 21,000 km of the planet, where it discovered two new moons (almost smacking into one of them in September 1979) and a new "F" ring. The spacecraft also discovered and charted the magnetosphere, magnetic field and mapped the general structure of Saturn's interior. The spacecraft's instruments measured the heat radiation from Saturn's interior and found that its planet-sized moon, Titan, was too cold to support life.
The irregularities in ring silhouette and shadow are due to technical anomalies in the preliminary data later corrected.