Mission Objectives Overview  ===========================     Faint Rings    -----------      Observations of Saturn's faint E, F and G Rings are best made      when the main rings are especially dark, such as close to the      moments of the Earth crossings and during the brief periods      when the Sun and Earth are on opposite sides of the ring      plane.  Observations reveal radial and vertical structures,      illuminating, for example, the relationship between the E      Ring and the embedded moon Enceladus.  Photometry and      spectrophotometry over a range of phase angles can be used to      better define the particle population in each ring.      Ring Thickness and Event Timing    -------------------------------      Observations of the photometric thickness of the rings, as      seen edge-on, may reveal whether this is caused by bending      waves, embedded moons, contributions from the projected E, F,      and G Rings, or some combination of the above.       Stellar occultations have led to a tentative detection of the      precession of the ring plane due to solar torques, and the      observed rate implies an advance of ~2 hours in the time of      RPX during the 15-year interval since the Voyager encounters.      Accurate timing of the crossing(s) could result in a      confirmation of this precession rate, or at least provide an      essential zero-point for future studies.      'Dark Side' Ring Viewing    ------------------------      Observations of the 'dark side' of the main rings are      possible during two extended periods when Sun and Earth are      on opposite sides of the ring plane: 21 May-11 August 1995      and 19 November 1995-11 February 1996.  During the latter      period, Earth is up to 2.5 degrees above the ring plane while      the Sun is in or below the plane, offering an excellent      opportunity to observe light transmitted through the C Ring      and the Cassini Division.  Photometry in these unusual      viewing geometries provides a unique set of constraints on      models of light scattering by denser planetary rings.      Detections of Small Satellites    ------------------------------      The small Saturnian satellites Pan, Atlas, Prometheus,      Pandora, Helene, Telesto, and Calypso have not been seen      since the Voyager encounters.  Janus and Epimetheus have been      seen only rarely.  New detections will make it possible to      refine their orbits substantially.  In addition, periods of      ring plane crossing are ideal for detecting previously unseen      moons.      Satellite Eclipses and Mutual Events    ------------------------------------      During the period 1993-1996 a very large number of eclipses      and occultations of the satellites by Saturn (and some by the      rings) will take place, as well as an extensive set of mutual      satellite occultations and eclipses in 1995.  Most eclipses      commence in October 1994 and continue through to August 1996,      but are most readily observed well away from opposition or      conjunction.  The mutual events, which occur only near the      passages of Earth through the ring plane, last from January      1995 to September 1996, with the highest frequency in      November 1995-January 1996.       A large set of mutual event observations in 1995 should lead      to significant improvements in the orbits for all the inner      satellites (S1-S6), and may help to establish better the      amplitudes and frequencies of the resonant librations      involving S1-S4.  Such observations may also permit mapping      of albedo patterns on the satellites.