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Cassini-Huygens: Mission to Saturn and Titan Cassini-Huygens: Mission to Saturn and Titan
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OVERVIEW - Introduction

Saturn filled Cassini's narrow angle camera as the spacecraft approached in March 2004.
Saturn filled Cassini's narrow angle camera as the spacecraft approached in March 2004.

With its stunning rings and dozens of moons, Saturn is an intriguing planet for many reasons. The giant planet has a huge magnetosphere and a stormy atmosphere with winds clocked at about 1,800 kilometers per hour (1,118 mph) near the equator. These super-fast winds, combined with heat rising from within the planet's interior, cause the yellow and gold bands visible in its atmosphere.

Like Jupiter, Uranus and Neptune, Saturn is a gas giant. It is made mostly of hydrogen and helium.

Saturn's rings in true color.
Saturn's rings in true color.

'Jewel of the Solar System'
Saturn's beautiful rings are what set it apart from the other planets in our solar system. It is the most extensive and complex ring system in our solar system, extending hundreds of thousands of miles from the planet. Made up of billions of particles of ice and rock - ranging in size from grains of sugar to houses - the rings orbit Saturn at varying speeds.

There are hundreds of individual rings, believed to be made of pieces of shattered moons, comets and asteroids. Each of the billions of rings particles orbits the planet on its own path.

For centuries, Saturn and its rings puzzled observers. Italian astronomer Galileo Galilei, the first to use a telescope to explore space, couldn't understand why Saturn looked so different in the night sky at different times. We now know this is caused by a shifting in our view of the ring plane. The rings are virtually invisible when they are edge-on to Earth. The rings seem to reappear months later as our angle of view changes.

Titan's thick, hazy atmosphere.
Titan's thick, hazy atmosphere.

Despite tremendous advances in observations in the 400 years since Galileo began studying Saturn's rings, many questions remain about the composition and structure of the rings.

Many Moons
Saturn's many known moons are equally mysterious, especially Titan. Bigger than Mercury and Pluto, Titan is of particular interest to scientists because it is one of the few moons in our solar system with its own atmosphere. The moon is cloaked in a thick, smog-like haze that scientists believe may be very similar to Earth's before life began more than 3.8 billion years ago. Further study of this moon promises to reveal much about planetary formation and, perhaps, about the early days of Earth as well.

Iapetus' light and dark terrain.
Iapetus' light and dark terrain.

In addition to Titan, Saturn has many smaller icy satellites. Some, like Pan, Atlas, Prometheus, and Pandora, are "shepherd moons" that herd Saturn's orbiting particles into distinct ring. Some moons produce twisting and wave patterns in the rings.

One moon, Enceladus, is one of the shiniest objects in the solar system. It's about as wide as Arizona and covered with water ice that reflects sunlight like freshly fallen snow. And strange Iapetus has one side black as asphalt and the other as bright as snow. All of Saturn's moons are unique and intriguing science targets.

Taking a Closer Look
Four NASA spacecraft have been sent to explore Saturn. Pioneer 11 was first to fly past Saturn in 1979. Voyager 1 flew past a year later, followed by its twin, Voyager 2, in 1981.

The Cassini spacecraft is the first to explore the Saturn system of rings and moons from orbit. Cassini entered orbit on Jun. 30, 2004 and immediately began sending back intriguing images and data. The European Space Agency's Huygens Probe dove into Titan's thick atmosphere in January 2005. The sophisticated instruments on both spacecraft are providing scientists with vital data and the best views ever of this mysterious, vast region of our solar system.

Cassini-Huygens is an international collaboration between three space agencies. Seventeen nations contributed to building the spacecraft. The Cassini orbiter was built and managed by NASA's Jet Propulsion Laboratory. The Huygens probe was built by the European Space Agency. The Italian Space agency provided Cassini's high-gain communication antenna. More than 250 scientists worldwide are studying the data streaming back from Saturn on a daily basis.

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Last Updated: 01.10.2008
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