[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!>

[EccentricAnomaly]

Orbiting Phoebe might also me possible... but its lower gravity would make staying in orbit much harder than at Iapetus.

[nprev]

Orbiting Phoebe might also me possible...  but its lower gravity would make staying in orbit much harder than at Iapetus.

Here's a strange thought: I have no idea where Chiron or any of the other Centaurs will be with respect to Saturn at the end of the primary mission, but would it be possible to reach one of them for a final flyby with any conceivable final propellant load?

[tasp]

IIRC, one of the many Pluto probe ideas floated in the last 25 years was to encounter Chiron (distantly) on its' way to Pluto and the great void beyond.

This doesn't help your specific query, but a Chiron encounter has been discussed.

Is Chiron the object that showed some emission activity back in the early eighties?

[nprev]

IIRC, one of the many Pluto probe ideas floated in the last 25 years was to encounter Chiron (distantly) on its' way to Pluto and the great void beyond.

This doesn't help your specific query, but a Chiron encounter has been discussed.

Is Chiron the object that showed some emission activity back in the early eighties?

Apparently, it grew a cometary coma in 1988 and is now known both as 2060 Chiron and 95P/Chiron...an interesting object indeed! The Wikipedia entry has some good additional info: http://en.wikipedia.org/wiki/2060_Chiron

Anyhow, Chiron or one of the other Centaurs would certainly be a great extended mission target for Cassini in the unlikely event that this was possible...

[Guest_BruceMoomaw_*]

There was never any chance of having the same craft flyby both Chiron and Pluto, but Alan Stern did propose launching a duplicate of the Pluto flyby craft to fly by Chiron.

[Decepticon]

Didn't Russia want to add a "Zond" Lander to the Pluto mission? I remember seeing that somewhere!

[Guest_AlexBlackwell_*]

Didn't Russia want to add a "Zond" Lander to the Pluto mission? I remember seeing that somewhere!

I recently posted a brief note about this over in the "New Horizons, Pluto and the Kuiper belt" thread.

[Guest_AlexBlackwell_*]

For various geometric reasons, Cassini's Iapetus v-infinity is around 2 km/s.  Given a very high apoapsis ( > 200 RS), a maneuver of around 100 m/s or so could bring that v-infinity down to 0 km/s (a parabola).  And then maybe some sort of Lissajous orbit would be possible that would give a low orbit insertion DV.  But such a scenario may just barely be possible using all of Cassini's on board DV (as of today, giving up the rest of the prime mission), and would require a Phd Thesis amount of work into the trajectory design...    So getting into Iapetus orbit isn't practical, but I'd say it just might be possible.

I can't remember where I saw it discussed, but I seem to recall seeing some rough, back-of-the-envelope-type calculations dealing with placing a spacecraft in orbit around some of the larger saturnian satellites (including Titan); as you point out, V-inf would be much favorable for Iapetus than Titan. In any event, from what I remember, a resonance would be set up with the target body, and when the spacecraft was close enough, fuzzy boundary effects (with Saturn as the third body) would capture the spacecraft in orbit.

A similar orbital insertion technique was once envisioned for the now-defunct Europa Orbiter.

[Guest_AlexBlackwell_*]

I chime in and make the pot $0.04

I note the Project has "tentatively" selected the T18 and T19 flyby altitudes as 960 km and 980 km, respectively, while the T20a ORS/T20b RADAR thru T25 altitudes get raised back up above 1000 km. And the next 950 km flyby after T16 is T32a INMS/T32b solar occultation.

It's been a year since I posted the message above, so I'll perform CPR ("cyber"-pulmonary resuscitation) and temporarily revive this dead thread

Today's Cassini's Significant Events Report publicly reveals the resolution of the INMS/ORS "conflict" for the T32 flyby. TOST was at an impasse, so the Project Scientist made the call, and of the two options noted above (i.e., T32a INMS/T32b solar occultation), INMS won out.

Now all that's needed is for someone on ISS or VIMS to file an emergency appeal in federal court to stay the decision pending ultimate resolution in the Supreme Court of the United States.

This post has been edited by AlexBlackwell: Dec 15 2006, 08:32 PM

[volcanopele]

Now all that's needed is for someone on ISS or VIMS to file an emergency appeal in federal court to stay the decision pending ultimate resolution in the Supreme Court of the United States.

We had nothing to do with T32 C/A. The conflict was between INMS and UVIS (solar occultation). I'm sure we have observations planned for T32, but it doesn't matter which instrument was selected for that pass.

[Guest_AlexBlackwell_*]

We had nothing to do with T32 C/A. The conflict was between INMS and UVIS (solar occultation). I'm sure we have observations planned for T32, but it doesn't matter which instrument was selected for that pass.

Oops. You're right. I meant to type UVIS instead of VIMS.