In September 2017, after 20 years in space, NASA deliberately flew the Cassini spacecraft into Saturn and let it burn up like a meteor — not because it had failed, but because it had found a possibly habitable ocean on the moon Enceladus that a dead spacecraft could one day contaminate.

In September 2017, after 20 years in space, NASA deliberately flew the Cassini spacecraft into Saturn and let it burn up like a meteor — not because it had failed, but because it had found a possibly habitable ocean on the moon Enceladus that a dead spacecraft could one day contaminate.

In September 2017, after twenty years in space and thirteen years orbiting Saturn, NASA pointed the Cassini spacecraft into the planet and let it burn up like a meteor. The probe was not broken. It had just spent more than a decade transforming Saturn from a distant ringed world into a system of storms, seas, plumes, and hidden oceans, and one discovery above all sealed its fate. Cassini found that Enceladus, a small icy moon, hides a global sal…