[X] My Assistant

[edstrick]

tallbear: "....However, the Cassin Tour will be altered in early 2006 and these opportunities may go away while others may appear.....

Uh... Say WHAT?....is this a branch to an entirely different series of encounters than the second half of the primary mission that they've been designing in (necessarily) obsessive-compulsive detail for the last decade? Did they have to retarget to make a close flyby of a Vogon Mothership? Or did they find a spinning blue telephone call-box floating in Saturn orbit? <grin!>

[Guest_BruceMoomaw_*]

Uh-uh -- it would be HARDER to orbit Iapetus than any of the other moons. Consider: if you had a spacecraft in the same orbit around Saturn as Iapetus, you would to pull a really huge rocket burn to lower its periapsis to intersect Titan's orbit. Well, the biggest orbit you can possibly pull off using Titan gravity assists is, of course, one with its periapsis at Titan's orbit -- which means that you'd have to make a comparably huge rocket burn to loft the craft up into a near-Iapetus orbit, from which you could then brake it into orbit around Iapetus. (Ditto if you made the two burns at the same time.) The only other possible way would be to make gravity-assist flyby after flyby of Iapetus -- dozens of them, and maybe even HUNDREDS, given its low mass -- to get it into a near-Iapetus orbit that way. (Messenger and Europa Orbiter will use this technique to almost match orbits with Mercury and Europa in order to brake into orbit around them, but they're dealing with far more massive target objects toan Iapetus.)

Nope; Titan -- given the ease with which we can use gravity-assist flybys to get into a near-Titan orbit, plus the extent to which we can use aerobraking to help slow the craft down -- is by far the easiest moon for Cassini to get into orbit around. If we can't do that -- and Robert Mitchell has told me that it's totally impractical -- we had better write off any idea of leaving the craft in orbit around any Saturnian moon.