Mission Description

On 15 October 1997, a two-story-tall robotic spacecraft launched from the Cape Canaveral Air Force Station began a journey of many years to reach and explore the exciting realm of Saturn, the most distant planet that can easily be seen by the unaided human eye. In addition to Saturn's interesting atmosphere and interior, its vast system contains the most spectacular of the four planetary ring systems, numerous icy satellites with a variety of unique surface features, a huge magnetosphere teeming with charged particles that interact with the rings and moons, and the intriguing moon Titan, which is slightly larger than the planet Mercury, and whose hazy atmosphere is denser than that of Earth.

The Cassini-Huygens Mission to Saturn and Titan is an international venture involving the National Aeronautics and Space Administration (NASA),the European Space Agency (ESA), the Italian Space Agency (ASI), and several separate European academic and industrial partners. The mission is managed for NASA by the Jet Propulsion Laboratory. The spacecraft will carry a sophisticated complement of scientific sensors - including the Ultraviolet Imaging Spectrograph (UVIS), built at LASP - to support 27 different investigations to probe the mysteries of the Saturn system. The large spacecraft will consist of an orbiter and ESA's Huygens Titan probe. The orbiter mass at launch was nearly 5300 kg, over half of which is propellant for trajectory control. The mass of the Titan probe (2.7 m diameter) is roughly 350 kg.

The purpose of the mission is to perform close-up studies of Saturn, its rings, moons, and magnetic environment. Saturn's largest moon, Titan, is a target of special interest because of atmospheric and perhaps surface characteristics it shares with early Earth. The instrument-laden Huygens probe will descend via parachute to Titan's surface to directly sample the atmosphere and provide our first view of its surface.

What we know about Titan is certainly tantalizing. Its brownish-orange, hazy atmosphere of nitrogen, methane, and complex array of carbon-based molecules hides a frigid surface that may contain lakes of liquid ethane over a thin veneer of frozen methane and ammonia, which in turn probably overlies a mantle of frozen water ice. As high-energy particles and ultraviolet light bombard the nitrogen and methane molecules, reactions create a variety of organic molecules that clump together and rain slowly down upon the mysterious surface below. In many ways, Titan's environment may resemble the chemical factory of primordial Earth. Though life is unlikely due to the extreme cold, Titan may still provide valuable clues to the chemistry of early Earth.

The benefits derived from the Cassini mission are significant. Aside from the rewards of international cooperation and the excitement of the discoveries that are anticipated, new technology features include powerful new computer chips, solid-state recorders, gyroscopes with no moving parts, and solid-state power switches. As Cassini transmits its findings from Saturn during the period from 2004 to 2008, the results are bound to inspire young and old alike to learn more about science and contemplate issues ranging from the origin of the solar system to the beginning of life on Earth.

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