Although I freely admit to being a rabid, foaming at-the-mouth Mars fanatic, I must confess that Cassini is almost as exciting as Mars Exploration Rover (MER). The Huygen Probe which is to land on Titan will be the high point. Huygen will be (I hope) ESA's first successful lander on another world. There are future Titan landers waiting in the proposal writing pipeline. I've been involved in some "pre-Phase A" Titan studies. Titan's atmospheric chemistry is a huge walloping unknown (it's mostly nitrogen with a dab of methane). That dab of methane makes all the difference in the world concerning the design of an aeroshell. In the shocklayer, the methane decomposes into hydrogen and atomic carbon while the molecular nitrogen decomposes into atomic nitrogen. A percentage of the atomic carbon and nitrogen will recombine into cyanide gas, CN. CN is an incredibly efficient radiation emitter (red and ultraviolet). The concentration of CN in the shocklayer can change the situation of having almost no heat flux to the aeroshell burning up in a flash (CN is also a problem for extremely large Mars aeroshells). We've got our fingers crossed that this won't cause problems with Huygen.

Gary