International Science Team Details Observation Plans

March 10, 1999

The Cassini spacecraft remains in excellent health as it continues on its long voyage to Saturn. Current spacecraft activity is dominated by routine maintenance of computer and mechanical systems onboard. The next batch of commands that will operate the spacecraft over the next nine weeks is scheduled to be radioed to Cassini later this week.

Last weekend, the antenna through which Cassini's telecommunications are conducted was switched back from one of two low-gain antennas to the other to accommodate the changing geometry as Cassini moves along its flight path. The high-gain antenna, which will be used as the primary antenna when Cassini reaches Saturn, was recently used to check out each of Cassini's scientific instruments.

Some 60 members of the international Cassini/Huygens science team gathered at JPL last week for detailed planning of scientific observations of Saturn, and to discuss opportunities to study the planets Cassini will pass on the way -- Venus, Earth and Jupiter. The science team resolved to adopt a specific orbital tour plan for Cassini's four years in orbit around Saturn. The plan allows for 44 close flybys of the large moon Titan, which is a prime target for the entire Cassini/Huygens mission.

Each flyby of Titan will represent an opportunity for Cassini's instruments to closely study that moon's atmosphere, interior, surface characteristics and interactions with Saturn's magnetic environment. One instrument, the Titan radar mapper, will use imaging radar to "see" through Titan's opaque, brown-orange atmosphere to reveal the surface in photograph-like detail. The observations made by the Cassini orbiter will complement those made by the European Space Agency's Huygens Probe, which will drop via parachute onto Titan's surface, studying the atmosphere, its chemistry, weather, and cloud structure on the way down while making additional measurements on the surface. The tour selected also allows superior, long-term studies of Saturn's rings at varying illuminations,
detailed global mapping of Saturn, and measurements of various regions within Saturn's magnetic environment over time. In addition, the tour includes three specially targeted close flybys of the moon Enceladus, and one each of Dione, Rhea, Hyperion and Iapetus. Many opportunities exist for additional detailed studies of all of Saturn's many moons over the course of the mission.

Cassini is traveling at a speed of about 81,100 kilometers per hour (50,500 mph) and has traveled more than 1.2 billion kilometers (745 million miles) since launch. The mission is managed by NASA's Jet Propulsion Laboratory, Pasadena, Calif. JPL is a division of the California Institute of Technology, Pasadena, Calif.

Additional information about Cassini-Huygens is online at

Cassini will begin orbiting Saturn on July 1, 2004, and release its piggybacked Huygens probe about six months later for descent through the thick atmosphere of the moon Titan. Cassini-Huygens is a cooperative mission of NASA, the European Space Agency and the Italian Space Agency. JPL, a division of the California Institute of Technology in Pasadena, manages the mission for NASA's Office of Space Science, Washington, D.C.

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