Here you can see three RTGs on a model of the Cassini probe. These three powered the Cassini probe for nearly 20 years. The Cassini mission sent back extremely useful data about Saturn and its many moons which scientists continue to use in important studies.
The Cassini Probe
The Cassini space probe was launched by a Titan IVB/Centaur rocket. At launch, it weighed approximately 5700 kilograms, was 6.8 meters tall, and 4 meters wide. It is about the same size as a 30 person school bus.