As of this writing, Cassini observations of Saturn's rings are less than one-third complete. Seven optimized orbits have been devoted partly to ring studies, and approximately thirty-eight more orbits remain in the tour, of which rings observations represent a decent fraction. Furthermore, if all goes well, Cassini is planning an extended mission which will continue until after the Sun crosses the edge-on rings and the north face of the rings is once again lit. Even a moment's thought reveals the depth of return which will benefit future ring scientists; the two Voyager encounters contained perhaps a few weeks worth of data each, of which the day or two near closest approach of each spacecraft represented the richest part. Each periapse pass of Cassini contains as much data as one Voyager encounter, taken with more and better instruments. Voyager had a single radio occultation (Cassini will have 14) and a single stellar occultation (Cassini will have about 80).
Analysis of the two Voyager encounters required nearly 20 years to complete, and the Cassini data set is nearly 100 times as large and complex. This is partly because
Cassini has entirely new instruments and partly because of the extended and complex orbital tour. The ring scientists responsible for planning these observations are a small and dedicated crew, but the necessity for assuring that the proper observations get designed, taken, and calibrated has taken priority over the fun of analyzing and publishing results once they arrive—a situation which continues as this chapter is written and will continue for several more years, because ongoing updates to the mission profile require ongoing changes in observing plans. It's reminiscent of a line from a popular song relating to poker: "Never count your money while you're sitting at the table—there'll be time enough for counting when the dealing's done.'' Generations of ring scientists will be playing with the cards dealt by this remarkable mission, still in its early days.
Was this article helpful?