[X] My Assistant

[imran]

Whether this is a two-year extension or longer I'd still have to go with Titan. There is so much of this world which we don't understand and have only begun to unveil that it begs us to focus our attention on this dynamic world. Some important questions that may only be answered with additional flybys:

- What is the source of methane in the atmosphere?
- Are there any bodies of liquids on the surface?
- Is there active precipitation?
- Is Titan geologically active, i.e. cryvolcanism, tectonism, etc?
- What is the extent of the organics present?
- Is there an ammonia/water mixture under the surface?

[Bart]

Wouldn't it be possible to set up the flybys so that the 'disturbance' of Titan was mostly focused into an inclination change? I'm sure the MAPS guys would love that anyway.

Also, if Titan gravity assist maneuvers can move the apoapsis from Iapetus' orbit to Titan's and back in a few orbits, surely it can't be that hard to adjust the periapsis from Mimas' orbit to Titan's?

Bart

[Guest_AlexBlackwell_*]

Also, if Titan gravity assist maneuvers can move the apoapsis from Iapetus' orbit to Titan's and back in a few orbits, surely it can't be that hard to adjust the periapsis from Mimas' orbit to Titan's?

It all depends on one's definition of "that hard." Deterministic delta-V is one of the prime limiting factors. Of course, it goes without saying that science objectives (e.g., desirability for icy flybys, occs, etc.) are also in the trade space.

BTW, one really interesting if not wild EM idea I heard was a suggestion to jettison the main engine cover and use it as an impactor (à la Deep Impact).

[Guest_BruceMoomaw_*]

BTW, one really interesting if not wild EM idea I heard was a suggestion to jettison the main engine cover and use it as an impactor (à la Deep Impact).

It would be hard to predict just where it would hit, wouldn't it? (And of course you wouldn't want to do it until you were done using the engine.)


What the periapse of the final orbit planned during the Primary Mission, and how does it compare to the orbital distances of Mimas and Enceladus? (I could look this up, but I'm too lazy.)

[Guest_AlexBlackwell_*]

It would be hard to predict just where [the main engine cover] would hit, wouldn't it?

Probably, since the main engine cover wasn't designed for impact experiments. Assuming, though, that the ejection dynamics could be accurately modelled, I wouldn't see any showstoppers for such an experiment. Just place Cassini on an intercept trajectory with, say, Rhea or Tethys and let 'er rip. Then perform an orbiter deflection maneuver to set up the flyby geometry. Hey, that technique sounds familiar, doesn't it?

This post has been edited by AlexBlackwell: Mar 23 2006, 06:29 PM

[JRehling]

Probably, since the main engine cover wasn't designed for impact experiments. Assuming, though, that the ejection dynamics could be accurately modelled, I wouldn't see any showstoppers for such an experiment. Just place Cassini on an intercept trajectory with, say, Rhea or Tethys and let 'er rip. Then perform an orbiter deflection maneuver to set up the flyby geometry. Hey, that technique sounds familiar, doesn't it?

If such a daredevil thing were attempted, I think Iapetus would be the strong favorite, since that might probe the thickness of the dark stuff. Dione might be a distant third, since it has some kinda dark stuff. Enceladus would obviously be verboten; attempt no crashing there.