The Cassini-Huygens space probe ended its 20-year mission last Friday with a fiery dive into the atmosphere of Saturn, ensuring its destruction after 13 years studying the massive planet, its rings and its moons. Data collected from the mission have changed the way scientists now think about Saturn and our part of space: There is open speculation about the possibility of life within our solar system. Space scientists are already thinking about ways to follow up on Cassini's incredible discoveries. There is no guarantee that there will be a next mission to Saturn, however. If ever there was a reason for multinational collaboration and cooperation, space exploration is it.

Cassini, a collaboration between the U.S., European and Italian space agencies, was launched Oct. 15, 1997. It took nearly seven years for the probe to travel the 1.4 billion km to Saturn, where it settled into a planetary orbit.

A year after its arrival, on Dec. 25, 2004, the Huygens module separated from Cassini and descended to Titan, the largest of Saturn's moons, where it successfully landed about three weeks later. Huygens was the first spacecraft to successfully land in the outer solar system and the first landing on a moon that is not our own. The probe sent data for nearly two hours before shutting down. While data collection and transmission was short, the content was astounding. The surface of Titan is pocked with valleys, rivers, lakes, and seas that distribute liquid methane across the moon. In one of the most striking discoveries, it appears as though there is an ocean beneath Titan's crust. The probe confirmed the composition of the hydrocarbon lakes and discovered indications of other organic molecules.