CICLOPS: Cassini Imaging Central Laboratory for OPerationS

The ISS camera onboard the Cassini Spacecraft orbiting Saturn has observed the enigmatic moon Iapetus for over three years now, but always from great distance. The so-far closest approach occurred at New Year's Eve 2005 when a range of 124000 km was achieved. Numerous discoveries have been made so far [e.g., 1,2,3]: The equatorial ridge on the leading and anti-Saturn side, a latitude dependence of the characteristics of the dark terrain, an unusually high number of giant impact basins, the latitudinal dependence of bright and dark crater rims, a global color dichotomy that shows different boundaries than the more obvious brightness dichotomy, the true (crater) nature of the "moat" feature, and so on. Earlier discoveries from Voyager data [4,5] such as the irregular boundary between the bright and the dark hemispheres, the giant bright mountains on the anti- and sub-Saturn side ("Voyager" mountains), the ellipsoidal shape of the whole moon, impact craters within the dark terrain, the reddish color of the dark terrain, etc., have been confirmed. Promising attempts were made to explain the formations of the brightness and color dichotomies [6,7] and the ellipsoidal shape [8]. Besides many unanswered questions, a major missing piece is a very close-up view on the surface. This is planned for the targeted flyby on Sept. 10, 2007. Our Cassini group at FU and DLR in Berlin has the responsibility for the imaging observation planning.