The Cassini spacecraft roared off the Kennedy Space Center launchpad at 4:43 a.m. on Oct. 15. The spacecraft, the size and weight of an empty, 30-passenger school bus, will follow a trajectory that covers 2.2 billion miles over a period of 6 years and 9 months before it finally reaches its objective, the ringed-planet Saturn, in July, 2004. When it arrives it will launch a probe named Huygens to the surface of Titan, Saturn's largest moon. Then it will spend 4 years making close-up observations of the planet, its rings, and the five largest of its 18 satellites as it orbits the planet about 60 times.

        Cassini was launched inward toward Venus rather than outward. Its trajectory to Saturn will make use of Venus twice and Earth and Jupiter once each for boosts of its speed. The first boost is by Venus at the end of April next year, the second is also by Venus near the end of June, 1999, the boost from Earth comes near the end of August, 1999, and then Jupiter's boost is scheduled for early January of 2001. These gravity boosts from the planets will supply Cassini with the equivalent energy of more than 3 thousand tons of fuel. Additional gravity boosts from Saturn's moons after the spacecraft reaches the planet will supply the same amount of energy.

        On its first orbit of Saturn in 2004 it will release the probe Huygens, built by the European Space Agency and named for the seventeenth century Dutch optician Christian Huygens who discovered Titan and was the first to realize that Saturn's "ears" were really rings. The probe is expected to take about 2 ½ hours to descend through the only atmosphere of a moon in the solar system, radioing its information back to Cassini. Huygens' batteries will be nearly spent when it reaches the unknown surface, but there is a possibility of several minutes of information from the surface -- if a solid surface is found.

        The spacecraft is named for the French astronomer who discovered the Saturnian moons Tethys, Dione, Rhea, and Iapetus and the division between Saturn's A and B rings, named Cassini's Division after him. These moons, as well as Titan, and the structure and composition of the rings will receive a great deal of attention from the scientific instruments on board Cassini as planetary scientists attempt to learn more about the formation of the planet's satellite system.

        The planet Saturn and its environment are, of course, prime areas for study, too. To carry out the investigations in all of these areas, the spacecraft carries a Composite Infrared Spectrometer, an Ultraviolet Imaging Spectrograph, a Visual and Infrared Mapping Spectrometer, and an Imaging Science Subsystem containing wide angle and narrow angle cameras, all for Optical Remote Sensing. For Microwave Remote Sensing, Cassini carries a series of very stable radio transmitters and receivers and a microwave radar system. A Plasma Spectrometer, a Cosmic Dust Analyzer, an Ion and Neutral Mass Spectrometer, a Dual Technique Magnetometer, a Magnetospheric Imaging Instrument, Electric and Magnetic Field Sensors, a Langmuir Probe, and High, Medium, and Wide Band Receivers make up the instruments to study the fields and particles both in the vicinity of Saturn and in interplanetary space as Cassini makes its long journey to the sixth planet from the Sun.