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Cassini-Huygens


NASA's Cassini orbiter and ESA's Huygens probe comprise the most complex and ambitious mission ever sent to another world. After flybys of Venus, Earth, and Jupiter, Cassini-Huygens arrived at Saturn on June 30, 2004. After entering orbit at Saturn the spacecraft began a 4-year tour of the Saturn system comprising nearly 80 revolutions about the ringed planet, a tour that has now been extended by another two years. The tour includes 71 gravity-assist flybys of Saturn's largest moon, Titan, and dozens of flybys of Saturn's smaller attendant moons. The mission extension will allow Cassini to watch what happens to the rings and the planet on August 11, 2009, Saturn's equinox, when the Sun sets on the southern face of the rings and rises above the northern face for the first time in fifteen Earth years.

Before Cassini-Huygens' arrival, we could only imagine what the surface of Titan looked like. The two spacecraft separated on December 25, 2004, and on January 14, the Huygens probe parachuted through Titan's thick atmosphere, gathering data on composition, temperature, pressure, scattering properties, wind speed, and even the sound of its descent. The view of Titan revealed by Huygens' camera was astonishing: the landscape contained steep mountains dissected by river-cut valleys surrounded by dry lakebeds, much like the landscape of an Earth desert. When Huygens touched down, it survived longer than anyone expected, long enough to detect a whiff of methane wafting up from ground that had been warmed by the probe. The data set returned by Huygens has answered some questions about Titan but has also generated many new mysteries.

The Cassini orbiter is now more than a year into its primary mission to study Saturn, its emblematic rings, and its extended family of at least 50 moons. Cassini's 12 science instruments can examine Saturn across a vast range of the electromagnetic spectrum, from the far ultraviolet to microwave wavelengths, and can sample directly the energetic particles and magnetic fields in Saturn's space environment. Cassini returns new images to Earth nearly every day, allowing the public to follow its mission closely and participate in the discoveries. Cassini has revealed unexpected features in Saturn's atmosphere and magnetic field, discovered tiny new moons, watched structures in the rings form, move, and dissipate, and improved upon the Voyager spacecraft's views of nearly every one of Saturn's icy satellites.

Cassini-Huygens Facts
Launch date: October 15, 1997
Saturn orbit insertion: July 1, 2004
Huygens mission: January 14, 2005
End of primary mission: July 1, 2008