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Saturn and Its Complex Family Of Moons and Rings Unveiled
Sacramento (SPX) Feb 05, 2007 Cassini is now two and half years through its official "primary tour" of the Saturn system - and which is scheduled to last another 17 months before ending on June 30, 2008. During this primary tour Cassini will have made 46 close flybys of Titan (during one of which it dropped off the European Space Agency's Huygens Titan lander), four close flybys of the unexpectedly fascinating moon Enceladus, and one each of Tethys, Dione, Rhea, Hyperion, Iapetus and Phoebe. It will also have made longer-range but still scientifically interesting "untargeted flybys" of some moons, and extremely detailed observations of both Saturn itself including its weather patterns and magnetosphere, along with its complex ring system from a multitude of distances, latitudes and viewing angles. And while its flybys of Titan would have been necessary anyway -- since Titan is the only moon of Saturn that's big enough to retilt the spacecraft into radically new orbits -- it has of course revolutionized our understanding of that bizarre world by radar-mapping narrow strips of its surface beneath its obscuring orange organic "smog", and making fuzzier but more sweeping observations of the surface through that haze in the near-infrared wavelengths in which the haze is semi-transparent. Even on the basis of what its done so far Cassini must be considered a scientific and space art spectacular. It has revealed major new mysteries about Titan and Enceladus which have a direct relevance to the possibility that one or both moons have evolved microscopic life beneath its outer icy crust. Moreover, Cassini has apparently solved at least two of the biggest scientific mysteries about the Saturn system: the mysterious longevity of its ring system (whose particles should have been ground into dust and dispersed after only a few hundred million years), and the remarkable difference between Iapetus' black leading side and its bright whitish trailing side. At this time Cassini is now being directed to make repeated close flybys of Titan to tilt its orbit at a sharp angle allowing Saturn and its entire ring system to be seen for the first time "from above". In addition Cassini is being placed in an elliptical orbit with its apoapsis on Saturn's dayside, allowing protracted observation of its weather patterns. The spacecraft will then be directed to tilt its orbit even further such that by the end of the primary tour it will be in near-polar orbit tilted fully 74 degrees out of Titan's equatorial plane. This will allow the most detailed observations yet of Saturn's rings, along with the planet's polar weather patterns and auroras. Later this year in September, having completed most of the planned flybys of Saturn's smaller moons, Cassini will make its one close flyby of the distant and hard-to-reach moon Iapetus. Coming within 1500 km it will be able to make its best observations of Iapetus and hopefully solve the remaining puzzles about it. The following March in 2008 Cassini will make its closest flyby of Enceladus skimming a mere 23 km (13 miles) above the dramatic geyser-like water and ice plumes which Cassini discovered were erupting from Enceladus' south polar region. Getting this close will enable scientists to observe in unprecedented detail the source vents of the plumes and analyze the simple organic compounds that are mixed in with water vapor. Related Links Titan Virtual Tour at JPL Cassini at JPL Cassini images
Tour de Saturn Set For Extended Play
Sacramento (SPX) Feb 05, 2007Following the highly successful three phase extended mission by NASA's Galileo Jupiter orbiter, scientists working with NASA's Saturn orbiter Cassini are looking at how an extended mission would work for Cassini. From the time Cassini first entered orbit around Saturn, they have been working on the design of a possible extended tour for it as well, re-planning it on the basis of the craft's new discoveries about the Saturn system, as well as computer calculations of just how many interesting destinations they can reach using more Titan flybys. |
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