A Titan IV rocket lifted the Cassini orbiter and its piggybacked Huygens probe off the pad at Cape Canaveral, beginning a seven-year voyage to Saturn. The joint NASA-ESA-ASI mission would spend thirteen years orbiting the ringed planet, discovering active geysers on Enceladus and dropping a probe onto the hazy surface of Titan, before deliberately plunging into Saturn's atmosphere in 2017.
Cassini's launch carried real controversy: the spacecraft used a plutonium-238 power source, and protesters gathered outside Cape Canaveral fearing a launch failure could scatter radioactive material across Florida. NASA proceeded anyway, and the Titan IV-Centaur booster carried the nearly six-ton spacecraft — one of the largest and most expensive interplanetary probes ever built — cleanly into its trajectory.
The seven-year cruise included gravity-assist flybys of Venus, Earth, and Jupiter before Cassini finally entered Saturn orbit in 2004. Its most startling discoveries came from Saturn's moons: geysers of water ice erupting from cracks in Enceladus's icy shell, hinting at a subsurface ocean, and the Huygens probe's landing on Titan in 2005, which returned the first images ever taken from the surface of a moon in the outer solar system.
After thirteen years and 294 orbits, mission planners deliberately steered Cassini into Saturn's atmosphere in September 2017 to avoid any risk of contaminating potentially habitable moons — a controlled death for a mission that had utterly rewritten scientists' understanding of the Saturn system.