So long, farewell, Auf Wiedersehen, good night. On December 19, NASA’s Cassini spacecraft says “adieu” to Saturn’s moon Enceladus. At 12:49 p.m. Eastern, the probe will make a final pass by the moon, famous for towering water geysers and a saltwater ocean lurking beneath its icy crust.
Over the last decade, Cassini has revealed Enceladus to be one of the few potentially habitable locales in the solar system. Warm, salty seas and hydrothermal vents make Enceladus a tantalizing place to search for life outside of Earth. For its last gander at the moon, Cassini will measure how much heat is leaking through cracks in the ice where water vents into space.
The spacecraft will continue to orbit Saturn and visit other moons until September 15, 2017, when it’s scheduled for a fatal plunge into the planet’s atmosphere.