QUOTE (BruceMoomaw @ Dec 21 2004, 01:21 AM)
It's interesting to speculate on whether they might eventually decide to aerobrake Cassini into a polar orbit around Titan for a really thorough mapping of that world -- although it would be difficult....
Now that would be really neat! I'd imagine it wouldn't be really hard to do either.
1. At the end of Cassini's primary mission, we are in a near polar orbit about Saturn. We'd need an "equitorialization campaign," using Titan flyby's to place Cassini back in a co-planar orbit with Titan.
2. Depending on the resulting Titan co-planar orbit, we probably need to pump down (or pump up) Cassini's orbit using additional Titan flybys. Each one will lower the required capture delta-V to enter Titan's orbit. (Similar maneuver was planned for the aborted Europa Orbiter mission) Using this resonant encounter technique, we could probably get the required capture delta-V down to 100m/s or less. (Titan's gravity actually HELPS us with this)
3. The big one: Capture into Titan orbit. Do we use precious fuel for this? Or do we chance the FIRST EVER TRIED aerocapture manuever? Either way, we should enter an eccentric orbit with the maximum allowable Apoapsis.
4. From here, we just need to make shallow passes in Titan's thin upper atmosphere to gradually reduce the Apoapsis to the height of the target orbit.
5. After the target Apoapsis is reached, we will need a Periapsis raise burn at the next Apoapsis to bring the orbit out of the atmosphere and make it circular.
We have to consider how to orient Cassini during the atmospheric passes. My guess is to use point the HGA in the direction of travel. That will have the effect of protecting the rest of the spacecraft. (Similar to initial ring plane crossing) But the big question here is whether or not the HGA can stand the heating caused by the passes. As long as we're only hitting the outer fringe, it should probably be ok.
What could be easier?!?!