First results from the Jupiter observation campaign at the EGS
5 April 2001While Huygens 'sleeps' during most of the seven year trip to Titan, many of the Cassini Orbiter instruments have already started to obtain exciting scientific data. For example, during the gravity-assist manoeuvres aroundVenus and Earth in mid-1999, calibration measurements were made. These are important for understandingthe in-flight performances of the instruments and for preparing for the mission for which they have beendesigned - observations of Saturn and Titan.
Cassini-Huygens got its last gravity-assist boost during the Jupiter flyby in December 2000. It provided a unique opportunity for a 6-month long Jupiter observation campaign which started in early October 2000 and ended in late March 2001, in time for the 7th Huygens in-flight checkout to take place.
Cassini and Galileo teamed-up for a unique set of joint observations of the giant planet. Cassini-Huygens and Galileo have focused on studies of the dynamics and composition of Jupiter's atmosphere, the Jovian magnetosphere, the Io torus, the chemical composition of the Jovian dust streams, and observations of the Galilean moons Io, Europa, and first time observation of the small Jovian satellite Himalia.
At the EGS session on 'Observations of the Jovian system by Galileo and Cassini-Huygens', new results from these coordinated observations were presented. Highlights included analysis of the effects of the solar wind on the extended Jovian magnetosphere, which was unexpectedly inflated and highly variable during that period; Jovian aurorae also observed by the Hubble Space Telescope in December 2000 and in January 2001; 'dust astronomy' of the high speed Io dust streams, and remote observations by both spacecraft of satellites, rings and atmospheric features of the Jovian system.
Jean-Pierre Lebreton, Huygens Project Scientist and co-convener of the session together with Galileo's Project Scientist Torrence Johnson and Cassini Project Scientist Dennis Matson says: "We managed to put together a very interesting session to celebrate an historical moment in the exploration of Jupiter. We had two spacecraft observing the giant planet and its environment from two close vantage points, with excellent support from Earth-based observatories. It will take months and years to analyse all the observations and to publish them in the scientific literature. There was no better way to prepare for Saturn and Titan. Jupiter was the best calibration target we could find on our way to Saturn."