Cassini's Extended Mission, July 2008 to June 2010 Options

[nprev]

Good list.

One question: The rings or ring arcs around Rhea haven't been confirmed yet, have they? AFAIK, we have some inference from magnetometer readings & those odd crater chains on the surface, but that's it.

[tasp]

Yeah, the Rhea flyby in (IIRC) March hasn't had any F&P data released yet. If there is something wonderful forthcoming that would be great.


I didn't know about the outies light curve studies. Interesting to see if any oddments turn up. BTW, I can't think of any way light curve data would yield orientation of spin axis, but I would be happy to be wrong. I suppose colorimetry data on the outies would be asking too much too . . .

[jasedm]

Yes, perhaps me being a bit over-eager Nick!

The literature seems a little contradictory in some respects - when reading the reports, you get the impression that a set of rings or arcs is the only explanation for the data, but they can't be definitively confirmed without visual evidence.

Three instruments detected dust directly, and the magnetometer readings point strongly towards something present, as the pattern of fluctuations in the readings was mirrored on either side of Rhea (analogous to the discovery of Uranus' rings when they occulted a background star as seen from Earth). Then there is, as you say, the equatorial band of dark markings on the moon.

Visual observations during the close flyby failed to turn up anything, so if there are rings or arcs, then they're likely larger constituents, and probably with low albedo (that omnipresent dark stuff in the saturn system again)

Perhaps it would be better for now to put this in the "strongly circumstantial, but not confirmed" pot then....

Jase

[ngunn]

I would include sublimation/albedo/temperature feedback on Iapetus as a major discovery. Also there have been many more big discoveries on Titan besides the lakes, such as convective storms that produce precipitation, river valley networks, complex organic chemistry and the equatorial dune seas.

[jasedm]

Very detailed update of the Cassini trajectory information over at Emily's blog Thanks Emily!

Encounter distances for the remainder of the mission change a little, with some minuses and some pluses.

For example, Telesto's encounter distance in May 2012 rises from 2,868km to 10,989km and Helene in June 2011 rises from 1,807km to 6,982km

But Rhea's closest encounter distance in January 2011 drops from 201km to 76km, and Dione's closest approach in December next year drops from 199km to 99km.

As Emily says, lots of geek fun to be had here perusing the detail

Jase

[cbcnasa]

Awsome Cassini has turned out to be so much bigger than ever expected back in 1997.