Cassini Spacecraft Begins New Study of Saturn's Seasons

NASA's Cassini spacecraft has moved on to the next stage of its Saturn mission, which will allow scientists to study seasons and other long-term weather phenomena on the ringed planet and its moons.

Cassini began this new phase — a mission extension announced earlier this year — on Sept. 27. NASA is calling it the Cassini Solstice Mission, because the probe's activities will run through at least September 2017 — a few months after Saturn's northern summer solstice (when the sun is highest in Saturn's northern sky).

Cassini arrived at Saturn just after the northern winter solstice in 2004, so the mission extension should let astronomers watch several of the planet's seasons turn.

More discoveries to come

Cassini has made many discoveries since its launch in 1997, including previously unknown characteristics of the somewhat Earth-like world of Saturn's largest moon, Titan. The craft also detected a plume of water vapor and organic particles spewing from another moon, Enceladus.

The Cassini Solstice Mission will enable continued study of these intriguing worlds. It will also allow scientists to continue observations of Saturn's rings and the magnetic bubble around the planet, known as the magnetosphere, NASA officials said.

Near the end of the mission, the spacecraft will make repeated dives between Saturn and its rings to obtain in-depth knowledge of the gas giant. During these dives, Cassini will study the internal structure of Saturn, its magnetic fluctuations and ring mass, according to NASA officials.

Cassini entered orbit around Saturn in 2004 for a four-year tour of the Saturnian system. But in 2008, Cassini received a mission extension through September 2010 to probe the planet and its moons beyond equinox, when the sun was directly over the equator.

Equinox occurred in August 2009, marking a transition to spring in Saturn's northern hemisphere.

"After nearly seven years in transit and six years in Saturn orbit, this spacecraft still just hums along," Bob Mitchell, Cassini program manager at NASA's Jet Propulsion Laboratory in Pasadena, Calif., said in a statement. "With seven more years to go, the science should be just as exciting as what we've seen so far."

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