Spacecraft Cassini's grand finale

The Cassini spacecraft is one of NASA’s greatest achievements… exploration of the planet Saturn, its moons and its rings. But all good things much come to an end. After 20 years in space, Cassini is running out of fuel.

NASA's Cassini spacecraft is shown heading toward the gap between

Saturn and its rings in this artist's rendering.

Illustration by NASA/JPL-Caltech

But last night, just before midnight at the Jet Propulsion Lab in California, Cassini chalked up another accomplishment as the spacecraft passed between Saturn and its closest ring for the first time. Astrophysicist and science writer Ian O'Neill reflects on what he calls a "bittersweet ending."