Cassini Huygens Saturn Mission
On June 30, 2004, 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. Cassini completed its initial four-year mission to explore the Saturn System in June 2008. Now, the healthy spacecraft is working overtime on the Cassini Equinox Mission, seeking answer to new questions raised in Cassini's first years at Saturn. The mission's extension, through September 2010, is named for the Saturnian equinox, which occurs in August 2009 when the sun will shine directly on the equator and then begin to illuminate the northern hemisphere and the rings' northern face. Cassini will observe seasonal changes brought by the changing sun angle on Saturn, the rings and moons, which were illuminated from the south during the mission's first four years.
Cassini's observations of Saturn's largest moon, Titan, have given scientists a glimpse of what Earth might have been like before life evolved. They now believe Titan possesses many parallels to Earth, including lakes, rivers, channels, dunes, rain, snow, clouds, mountains and possibly volcanoes.
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 four years of the Cassini-Huygens saga 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 Cassini Equinox Mission, the spacecraft will be making 60 additional orbits of Saturn. These will include 26 flybys of Titan, seven of Enceladus, and one each of Dione, Rhea and Helene. The extended mission also includes studies of Saturn's rings, its complex magnetosphere, and the planet itself. Other activities for Cassini scientists will include monitoring seasons on Titan and Saturn, observing unique ring events, such as the 2009 equinox when the sun will be in the plane of the rings, and exploring new places within Saturn's magnetosphere.
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.
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.