[X] My Assistant

[Guest_AlexBlackwell_*]

Although the mission description document for the upcoming (February 27, 2006) T11 flyby hasn't been released to the public yet, here are the science highlights:

Imaging Science Subsystem (ISS) – will perform a global-scale mosaic of the sub-Saturnian hemisphere: covering the equatorial region from Fensal/Quivira/Aztlan to Aaru, and Tsegihi in the south. ISS also has a mosaic that ranges from the regional scale to high resolution and includes the southern part of Aztlan, the eastern part of Shiwanni Virgae, and Elba Facula. The closer mosaic will have pixel scales ~600-350 m.

Composite Infrared Spectrometer (CIRS) –will obtain information on trace constituents in Titan's stratosphere. Integrate on limb at two positions POINTING: Obtain information on CO, HCN, CH4. Integrate on disk at airmass 1.5-2.0. POINTING: -y to Titan, x away from sun.

Ultraviolet Imaging Spectrometer (UVIS) – will perform a global spectral map to study aerosol scattering and hydrocarbon absorption and distribution. This will also be UVIS’ first solar occultation. With the solar occultation UVIS can observe the extreme ultraviolet (EUV) spectrum below 110 nm and can sample opacity from nitrogen and methane and possibly some other hydrocarbons.

Visible and Infrared Mapping Spectrometer (VIMS) – will obtain new high resolution images that will help understand Titan's geology and the fate of CH4.

Magnetometer (MAG) - will take advantage of this encounter being upstream of the Titan/magnetospheric interaction. The spacecraft will fly through Titan’s middle ionosphere. Together with the T8 and T6 flybys, T11 will allow MAG to reconstruct the upstream equatorial ionospheric pile-up region.

Magnetospheric Imaging Instrument (MIMI) – will investigate micro-scale and near aspects of the Titan interaction by observing during about one hour period around an encounter. With -Y pointed toward Titan, when within 30 minutes of the targeted flyby, optimize secondary axis for co-rotation flow as close to the S/C -X, +/- Z plane as works with the other constraints on pointing. Also, measure Titan exosphere/magnetosphere interaction by imaging in ENA with INCA (when sun is not in INCA FOV).

Ion and Neutral Mass Spectrometer (INMS) – will obtain data regarding Titan’s atmospheric and ionospheric composition and thermal structure. INMS will also observe the magnetospheric/ionospheric interaction.

Radio and Plasma Wave Spectrometer (RPWS) – will study the interaction of the magnetosphere with Titan at intermediate distances for evidence of ion pickup, radio emissions, density profiles, and the general wave environment.

Radio Science (RSS) – will perform two Gravity Science Enhancement (GSE) passes occurring after the flyby in order to answer the question of whether Titan possesses an internal ocean. The GSE passes are crucial to de-correlate Titan's GM from the distance at closest approach.

[JRehling]

... covering the equatorial region from Fensal/Quivira/Aztlan...

They really need one name for this region -- something more formal than "H". I applaud the cultural diversity on a globewide basis, but they might have used similar-culture names for the features of the H. This German-Latin-Aztec combo is amusing, and it may grow on me, but it's kind of odd. It reminds me of a Steven Wright joke with the punchline "Bucky Goldstein."

[Guest_AlexBlackwell_*]

Magnetometer (MAG) - will take advantage of this encounter being upstream of the Titan/magnetospheric interaction.  The spacecraft will fly through Titan’s middle ionosphere. Together with the T8 and T6 flybys, T11 will allow MAG to reconstruct the upstream equatorial ionospheric pile-up region.

Note: I changed the passage above (viz., "...with the T8 and T6 flybys, T11 will allow MAG...") from the document I quoted. The original passage listed T10 instead of T11. Assuming it was a misprint, I changed it.

[volcanopele]

They really need one name for this region -- something more formal than "H". I applaud the cultural diversity on a globewide basis, but they might have used similar-culture names for the features of the H. This German-Latin-Aztec combo is amusing, and it may grow on me, but it's kind of odd. It reminds me of a Steven Wright joke with the punchline "Bucky Goldstein."

We pushed for a single name for the dark "H" feature and another name for the dark region surrounding Elba Facula, but it didn't come to pass. Still the H is only Fensal-Aztlan with Quivira being a bright feature within Fensal-Aztlan.

[Guest_AlexBlackwell_*]

The T11 flyby page is up.

[remcook]

"Composite Infrared Spectrometer (CIRS) –will obtain information on trace constituents in Titan's stratosphere. Integrate on limb at two positions POINTING: Obtain information on CO, HCN, CH4. Integrate on disk at airmass 1.5-2.0. POINTING: -y to Titan, x away from sun."

I see only nadcomps in the list unfortunately

[ugordan]

It's disturbing to see so many typos in these mission descriptions lately. Someone should really pass them through a spell-checker before release.

[Big_Gazza]

Titan flyby imagery coming through.

http://saturn.jpl.nasa.gov/multimedia/imag...eiImageID=64404

New territory to the east of Fensal Aztlan region.

POP

Thats the champagne cork....

[SFJCody]

Looks like there are a few new faculae to be named in Aaru - Senkyo... and something visible in RGB over Aaru?

[ugordan]

and something visible in RGB over Aaru?

Those are imaging artifacts, I've seen the cloud-like feature on several previous flybys and it always appears at that position. It's plainly visible probably due to heavy histogram stretching by the raw image generator and should go away once the image is properly corrected for flatfield/dust ring effects.

[alan]

Titan behind rings
http://saturn.jpl.nasa.gov/multimedia/imag...eiImageID=61037

Oops, thats from last month

[Decepticon]

I wonder if JPL is using a new technique? These images look very sharp for Raw images!

After the processing is done this should look Marvelous!

[volcanopele]

I wonder if JPL is using a new technique? These images look very sharp for Raw images!

After the processing is done this should look Marvelous!

BTW, a short burst from our REGMAP001 observation is now on the ground and in the JPL raw images page.

[RedSky]

New Titan raw images starting to appear. Lots of details...

http://saturn.jpl.nasa.gov/multimedia/imag...eiImageID=64404

Ed: Sorry... didn't see this was already posted.

[alan]

Some new areas visible
http://saturn.jpl.nasa.gov/multimedia/imag...8/W00013659.jpg
http://saturn.jpl.nasa.gov/multimedia/imag...8/N00051531.jpg
http://saturn.jpl.nasa.gov/multimedia/imag...8/N00051615.jpg
http://saturn.jpl.nasa.gov/multimedia/imag...8/N00051560.jpg
http://saturn.jpl.nasa.gov/multimedia/imag...8/N00051571.jpg
http://saturn.jpl.nasa.gov/multimedia/imag...8/N00051564.jpg

[David]

Here's a hopelessly obvious question, but one I've not seen the answer to. Most of the "dark stuff" (whatever it is) on Titan is concentrated in a connected, not-too-wide band that goes almost all the way around the equator. and some tens of degrees north and south of it; there are some blotches further south, and of course we can't see all of the northern hemisphere, but there's nothing in the part we can see north of the band.

Have there been suggestions for this peculiar distribution? Or isn't it worth commenting on?

[volcanopele]

Here's a hopelessly obvious question, but one I've not seen the answer to. Most of the "dark stuff" (whatever it is) on Titan is concentrated in a connected, not-too-wide band that goes almost all the way around the equator. and some tens of degrees north and south of it; there are some blotches further south, and of course we can't see all of the northern hemisphere, but there's nothing in the part we can see north of the band.

Have there been suggestions for this peculiar distribution? Or isn't it worth commenting on?

My answer is that it probably has to do with climate. titan's equatorial regions likely see very little rainfall on an average year, leading to far less fluvial erosion. Eolian processes dominate, with ice sand and hydrocarbon particulates infilling the topographic lows of the equatorial region. in the polar region, fluvial processes dominate over eolian processes, leading to more dark blotches from playas and a more relatively uniform topography.

[JRehling]

Here's a hopelessly obvious question, but one I've not seen the answer to. Most of the "dark stuff" (whatever it is) on Titan is concentrated in a connected, not-too-wide band that goes almost all the way around the equator. and some tens of degrees north and south of it; there are some blotches further south, and of course we can't see all of the northern hemisphere, but there's nothing in the part we can see north of the band.

Have there been suggestions for this peculiar distribution? Or isn't it worth commenting on?

The equatorial "stuff" is bounded by linear borders suggesting a tectonic origin: something like the Valles Marineris on Mars, but going more or less all the way around. Note that VM is pretty much parallel and near the equator of Mars. And Venus also has a roughly equatorial band of tectonic activity. Note that an oblate geoid could focus tectonic activity on the equator, while dissipation of angular momentum can move the axis of rotation so as to put the equator where an existing band of varied mass concentration lay!

So it seems, one way or another, Titan, which probably expanded as it froze, ended up faulting around what was or what became the equator and the decrease in altitude on that band provided a basin into which dark sediment eventually settled.

Since ISS shows Titan in monochrome (and VIMS hasn't shown the high latitudes all that well, and has had other limitations), we can't be sure that the equatorial dark stuff and the southern dark stuff are the *same* dark stuff. I suspect that the southern dark stuff is either seasonal wet areas that is only dark *now* (and might dry up next season) and/or areas that have accumulated sediment from frequent (seasonal?) past or ongoing wet seasons that filled "local" basins with the same kind of stuff that filled the equatorial tectonic basin(s).

This is somewhat speculative, but then we don't have all the data we'd like. Yet.

[Decepticon]

Has anyone attempted to peace a mosaic together yet?

Its nice to see new terrain covered on this flyby.

[edstrick]

The concentration of dark materials toward low latitudes *MAY* reflect a weak overall trend for surface winds to angle toward the equator, resulting in a net migration of mobile dark materials to lower latitudes. This could be associated with a year-averaged "Hadley Cell" atmosphere circulation, with net rising convection at the equater, averaged over the year.

[The Messenger]

The equatorial "stuff" is bounded by linear borders suggesting a tectonic origin: something like the Valles Marineris on Mars, but going more or less all the way around. Note that VM is pretty much parallel and near the equator of Mars. And Venus also has a roughly equatorial band of tectonic activity. Note that an oblate geoid could focus tectonic activity on the equator, while dissipation of angular momentum can move the axis of rotation so as to put the equator where an existing band of varied mass concentration lay!

So it seems, one way or another, Titan, which probably expanded as it froze, ended up faulting around what was or what became the equator and the decrease in altitude on that band provided a basin into which dark sediment eventually settled.

This is somewhat speculative, but then we don't have all the data we'd like. Yet.

Fascinating. The most obvious question is: Why isn't the Earth tectonically belly-banded?

[Holder of the Tw...]

Fascinating. The most obvious question is: Why isn't the Earth tectonically belly-banded?

Too many plates moving in too many directions, too fast.

[Phil Stooke]

I don't like the idea of equatorial tectonics (Iapetus notwithstanding) ... I'd be happier with an explanation for Titan involving winds or climate.

Phil

[Olvegg]

Equatorial tectonics also may be driven by Saturn tides - due to non-zero eccentricity of Titan orbit. Note that bright surfaces concentrate near equator as well - "continent" Xanadu, for example. It could be real continent, and its brightness could be due to young surface (or high, which is evidence for tectonic origin, too). Analogue of Pangaea. So dark regions may be real Titan oceans, though filled with solid rather than liquid sediments.