2007-09-10 Iapetus (rev 49): Pre-flyby discussion, Closest approach of this odd moon Options

[tasp]

With no particular evidence at all, I had just figured the radar scan would provide surface roughness estimates across it's swath to perhaps support a future rover mission.

If the 'original' Iapetan surface materials are distinguishable in some regard from the (possible) emplaced ringy material making up the ridge structure, that would be interesting to.

If an oblique impactor lofted materials that formed a ring system, the impactor might have had a differing composition and it's incorporation into the ring materials, and the subsequent emplaced structure, might yet be discernable.

[monitorlizard]

I don't know how Cassini's radar will be used at Iapetus, but here's a thought: if radar imaged a thin strip of the surface that crossed the boundary between the dark and light materials, you could look for changes in surface roughness. You could see if the transition from one region to the other were characterized by a gradational change or sudden change in surface roughness. That could provide evidence to support an endogenic or exogenic origin of the dark material, especially if combined with data from other instruments.

Unfortunately, that sounds like it might use too much data storage, but just maybe the Cassini extended extended mission will look favorably at another close Iapetus flyby.

[Toma B]

Hi!

I have just noticed what is the "Wikipedia's picture of the day for Sept 1st.
Iapetus

That's our Ugordan's image!!!

[ugordan]

Sweet

I'm not completely satisfied with how it turned out, though, namely a slight hue shift in the clear filter fill bugs me the most. Then again most casual viewers probably won't notice that unless they know what to look for. Touching up that mosaic has been on my to-do list for a while, but I never got around to doing it.

[TritonAntares]

Hi all,
here a link to FU Berlin I got just seconds ago:
049IA – Cassini Iapetus Targeted Flyby (Rev. 049, 10 Sep 2007)

There are a timeline, detailed information about bbservation requests and a table showing the flyby geometry included...
Here an updated overview of the VIMS requests:


But I've just to read for myself...

EDIT: Downlink times
A small fraction of the data will be downlinked to Earth on the late evening of Sept., 10. The majority will follow overnight (US) or during daytimes on Sept., 11 (Europe). Since the Iapetus data have a particularly high priority, all data will either be downlinked twice, or received by two stations simultaneously. The intermediate downlink late on DOY 253 allows to collect about 20% more data during the flyby than would be possible otherwise.

Bye.

[ugordan]

Wow, those are really detailed. It's probably as detailed a description as we'll ever get.
Based on satellite PR shot data - there will be a 1x5 WAC sweep of Saturn and moon system, in addition NAC RGB shots of all the major moons will be provided and a NAC ring scan. Here are simulations on the approximate pixel scales we can expect, note NAC has extra 200 pixels in horizontal direction so it has a bigger window:
Mimas
Enceladus
Tethys
Dione
Rhea - could turn out cool with Saturn's limb near, depending on exact time (closer to 02:40 UTC are better) - similar to Europa rising over Jupiter (except in color )
Titan
Hyperion

And a preview of the WAC view around the time. It'll be nice to see the lit side of rings again along with a moderate phase view of the planet.

[elakdawalla]

Yes, everyone, run, don't walk, to check out those web pages that TA posted the link to. I've been trying to digest all the information there for the last four days -- sorry I didn't share, but I told Tilmann I wouldn't post a link or blog until he was pretty much done, and not quite everything is up there yet. At this point, it's set for the weekend; there won't be more updates until Tuesday.

I LOVE the animation and map previews of each observation -- wish we had these for every targeted flyby!!!

Here is a preview of my digested version (no illustrations yet, and probably some typos, send me a PM if you notice any glaring errors)...
http://planetary.org/blog/Cassini_Iapetus.html

--Emily

[volcanopele]

Good grief, will I have to write a book to write the uber-preview for this flyby

[ugordan]

Lol VP, good luck topping this.

There's just so much information to digest here, it's almost like one step away from giving us spice kernels for the encounter.
The closest approach observation is ISS_049IA_ORSHIRES001_VIMS and it has an interesting coverage, 8 clear filter ISS footprints of the ridge. If Cassini ever provides a view akin to a view from an airplane, this will be it. The view flying literally over the ridge should be absolutely s.p.e.c.t.a.c.u.l.a.r. and allow for some great stereo shots as phase angle reduces from 83 to 29 degrees.

[scalbers]

Yes - really exciting details from FU Berlin. Thought I'd check whether these closest approach exposure footprints represent simultaneous or near-simultaneous WAC and NAC images? That will be great to see this mosaic at the two different scales.

[ugordan]

Steve, they're listed as 8 BOTSIMs so yes, they're simultaneous. I imagine the NAC frames will be at too high a resolution to make ends or tails, it's probably the WACs that'll produce the biggest "oooh" factor.

As for the NAC... what if we find boulders on Iapetus, too?

[Mariner9]

Oh my gawd. This blog is amazing. It's what I've always wanted for the other Icy moon encounters.


The number of observations is fantastic, and so far I'm just looking at the ISS footprints.

Combined with all the other observations Cassini will be making on this one flyby, I suspect we'll be seeing research papers coming out of this for years.

I'm already looking forward to ordering the special issue of Science magazine (if they do one), so it can go up on my shelf next to the Enceladus issue.

[Exploitcorporati...]

Holy shiskies...we are going to have our hands full after this flyby! Big thanks to TA for keeping us informed, to TD for enough information to choke the organism of your choice, and Emily for a wonderfully succinct blog distillation. Exciting times... a few days to Tethys and Rhea, and then on to the show. Give it up, you two-faced (expletives deleted).

Congrats to Gordan for the Wikipedia pic of the day!

[belleraphon1]

Just saw this post.

Holy Freekah Moly!!!!!!!!!!!!!!!! What a site! Thanks indeed TA.

As for the radar observations.... Iapetus has a strange radar signature seen from Earth...
http://www.space.com/scienceastronomy/myst...day_040426.html

"It is known that the bright side is mostly water ice, but we find it does not reflect the radar like other icy satellites that we've studied with the radar before," says study leader Gregory Black of the University of Virginia. "The ice on Iapetus appears much less reflective."

We will soon make an intimate connection with this Mistress of Mystery, and yet.... even this will just scratch the surface ............... I just do not think Iapetus is simple.

I CANNOT WAIT!!!!!!!!!!

Craig

p.s. all you UMSF folks are awesome.

[nprev]

Iapetus is, just maybe, the first example of a large KB object we can see up close. It's definitely got its own vibe, far different from the rest of the moons here...Sept should be a very exciting month indeed!