July 2006

Saturn's Night Colors

Just two years ago, the Cassini spacecraft entered orbit around Saturn to begin the first in-depth, up-close study of the ringed planet and its domain. Mission planners expected to find a treasure of opportunities for exploration and discovery, and they have. Now just halfway through its planned four-year grand tour of the Saturn system, the mission has already made some astonishing finds.

"We're looking at a string of remarkable discoveries," says deputy project scientist Dr. Linda Spilker, "about Saturn's magnificent rings, its amazing moons, its dynamic magnetosphere and about Titan's surface and atmosphere. Some of the mission highlights so far include discovering that Titan has Earth-like processes and that the small moon Enceladus has a hot-spot at its southern pole, geysers that spew out ice crystals and evidence of liquid water beneath its surface."

The extraordinary results from the Cassini spacecraft and the European Space Agency's Huygens probe, which plunged through Titan's dense, smoggy atmosphere to its surface, have appeared in more than 400 scientific articles. They've been the subject of a special issue of Nature magazine and three special issues of Science magazine.

The first two years of the Cassini-Huygens mission have brought a new understanding of the complex and diverse Saturn system. The next two years are expected to be just as exciting. During the second half of its mission, Cassini will be changing its orbit to provide never-seen-before views of the fabulous rings, searching in the gaps for new moons and mapping the ring structure. It will also fly 30 more times by Titan, a world much like an early Earth frozen in time.

Science Objectives

The Cassini-Huygens mission is guided by a basic set of science goals, which address many major scientific questions about the planet, Titan, Saturn's magnetosphere, the rings and the icy moons. These objectives are listed in the following sections devoted to those topics.

A separate team of scientists plans the activities and targets for each of the spacecraft's 12 instruments and analyzes the data. Each team is headed by a team leader or a principal investigator. Altogether, there are nearly 300 scientists from the United States and Europe participating in the mission. See Cassini Orbiter Intruments for more.