[X] My Assistant

[Guest_AlexBlackwell_*]

Since T11 just concluded, I guess it's not too early to post the science highlights for the T12 flyby:

Titan-12 Science Highlights

Radio Science Subsystem (RSS) - T12 provides the first Cassini tour opportunity for Radio Science (RSS) to observe Titan's ionosphere and neutral atmosphere using radio occultation, and Titan's surface using bistatic scattering. The radio occultation is the second ever of Titan, the first being a sole Voyager occultation in 1980. The measurements provide important high-spatial-resolution information about the large-scale structure of the ionosphere and atmosphere of Titan. The properties of the reflected signals provide important information about the surface region probed (physical nature).

Imaging Science Subsystem (ISS) - Global-scale mosaic extending over Shangri-La, Tui Regio, and western Xanadu, including a frame over Ontario Lacus to look for possible cloud activity.

Visible and Infrared Mapping Spectrometer (VIMS) - Search for and characterize midlatitude clouds, aurorae, hotspots, and changes in surface properties. VIMS will also characterize the geologic features, haze and composition of Titan's equatorial region.

Composite Infrared Spectrometer (CIRS) - Global mapping of trace species (CO, H2O, HCN) via rotational lines in the far-infrared by conducting inbound and outbound composition integrations.

RADAR – Will add to their radiometry and scatterometry coverage of Titan.

Radio and Plasma Wave Spectrometer (RPWS) - Thermal plasma density and temperature measurements, search for lightning and other radio emissions, characterization of plasma wave spectrum, and search for evidence of pickup ions.

Cassini Plasma Spectrometer (CAPS) - Observations of Titan's interaction with Saturn's magnetosphere.

Ion and Neutral Mass Spectrometer (INMS) - Determine atmospheric and ionospheric composition and thermal structure.

[Decepticon]

including a frame over Ontario Lacus to look for possible cloud activity.

Looking forward to that!

[elakdawalla]

Decepticon, I hope you aren't trying to make a statement by adopting Unicron, the Planet Eater as your avatar. I like the planets we have very much. (I fear I may be the only person in this forum [with the possible exception of 'Decepticon'] geeky enough not only recognize the reference but be sitting not 4 feet away from a VHS copy of Transformers: The Movie... )

Since T11 just concluded, I guess it's not too early to post the science highlights for the T12 flyby:
Radio Science Subsystem (RSS) - T12 provides the first Cassini tour opportunity for Radio Science (RSS) to observe Titan's ionosphere and neutral atmosphere using radio occultation, and Titan's surface using bistatic scattering. The radio occultation is the second ever of Titan, the first being a sole Voyager occultation in 1980. The measurements provide important high-spatial-resolution information about the large-scale structure of the ionosphere and atmosphere of Titan. The properties of the reflected signals provide important information about the surface region probed (physical nature).

I'm very surprised there hasn't been a radio occultation of Titan's atmosphere by Cassini yet. Have there been previous opportunities that haven't been taken advantage of, or is this the first good one there's been, and if so, why?

--Emily

[Phil Stooke]

An occultation is only useful if the spacecraft is transmitting back to Earth through the atmosphere. Since there's no scan platform, the s/c orientation is controlled by other observations. This may just be the first good chance to transmit to Earth without nixing other data collection.

Phil

[Guest_BruceMoomaw_*]

Decepticon, I hope you aren't trying to make a statement by adopting Unicron, the Planet Eater as your avatar. I like the planets we have very much. (I fear I may be the only person in this forum [with the possible exception of 'Decepticon'] geeky enough not only recognize the reference but be sitting not 4 feet away from a VHS copy of Transformers: The Movie... )

--Emily

Just as long as he doesn't start calling himself "Galactus"...

[Decepticon]

Decepticon, I hope you aren't trying to make a statement by adopting Unicron, the Planet Eater as your avatar. I like the planets we have very much. (I fear I may be the only person in this forum [with the possible exception of 'Decepticon'] geeky enough not only recognize the reference but be sitting not 4 feet away from a VHS copy of Transformers: The Movie... )

LOL That made my day!

[djellison]

I fear I may be the only person in this forum [with the possible exception of 'Decepticon'] geeky enough not only recognize the reference but be sitting not 4 feet away from a VHS copy of Transformers: The Movie... )

I have one at home There is also a building up the road at the University of Leicester that looks like Optimus Prime if you look at it the right way


You can see his head on the right here - http://www.le.ac.uk/admissions/open/081005...es/building.jpg

Doug

[The Messenger]

Decepticon, I hope you aren't trying to make a statement by adopting Unicron, the Planet Eater as your avatar. I like the planets we have very much. (I fear I may be the only person in this forum [with the possible exception of 'Decepticon'] geeky enough not only recognize the reference but be sitting not 4 feet away from a VHS copy of Transformers: The Movie... )
I'm very surprised there hasn't been a radio occultation of Titan's atmosphere by Cassini yet. Have there been previous opportunities that haven't been taken advantage of, or is this the first good one there's been, and if so, why?

--Emily

My daughter has a "Say something NERDY to me" bumper sticker - Does that count?

I read - somewhere - that the occultation experiments were on hold until Cassini passed on the dark side of Titan, but I am wondering: Are they broadcasting radio to the Earth during occultation, or using radio noise from the sun and Cassini's receiving instruments in this experiment?

[Guest_AlexBlackwell_*]

I'm very surprised there hasn't been a radio occultation of Titan's atmosphere by Cassini yet. Have there been previous opportunities that haven't been taken advantage of, or is this the first good one there's been, and if so, why?

Basically, and as Phil alluded to, the science trades for the tour haven't had RSS at the top of the priority queue so far, and most of the flyby geometries to date haven't been "RSS-optimized." RSS has some fairly high-level science goals at Titan (e.g., study north polar vortex and south polar convective clouds, retrieve temperatures in the lower troposphere, Ka-band sounding via HGA, bistatic scattering observations of Titan’s surface, gravity science flybys to determine Titan's dynamic Love number, etc.) and needs certain geometries. Upcoming flybys, including this set (T11-T14), aim to address this. Just a note: radio occultation can also be performed via the LGA.

That said, the various reference trajectory tweaks have had an effect. For example, RSS lost a good occultation at T3 when TOST re-integrated the T3 flyby sequence and redesignated it a RADAR pass instead of an RSS pass, though, as I understand it, the T3 occultation geometry was lost when the trajectory was adjusted, so it wasn't just a matter of RADAR winning out out in this particular instance. Nevertheless, at the October 29, 2004, TOST meeting an RSS team member described this loss as "heart-breaking" because T3 was the only Titan occultation in the whole tour (at that time) that hoped to probe the near-equatorial region, and the RSS team invested a great deal of effort in planning this measurement.

[Decepticon]

I'm surprised the T12 Flyby page is not up yet.

[ugordan]

I'm surprised the T12 Flyby page is not up yet.

Nothing out of the ordinary, they usually release the flyby mission description a day or two before the actual encounter.

[Guest_RGClark_*]

Decepticon, I hope you aren't trying to make a statement by adopting Unicron, the Planet Eater as your avatar. I like the planets we have very much. (I fear I may be the only person in this forum [with the possible exception of 'Decepticon'] geeky enough not only recognize the reference but be sitting not 4 feet away from a VHS copy of Transformers: The Movie... )
...
--Emily

Yes, but how many of us actually paid to see it in the theater?


- Bob C.

[Decepticon]

^ I am so Jealous!

[The Messenger]

Since T11 just concluded, I guess it's not too early to post the science highlights for the T12 flyby:

Titan-12 Science Highlights

Radio Science Subsystem (RSS) - T12 provides the first Cassini tour opportunity for Radio Science (RSS) to observe Titan's ionosphere and neutral atmosphere using radio occultation, and Titan's surface using bistatic scattering. The radio occultation is the second ever of Titan, the first being a sole Voyager occultation in 1980. The measurements provide important high-spatial-resolution information about the large-scale structure of the ionosphere and atmosphere of Titan. The properties of the reflected signals provide important information about the surface region probed (physical nature).

It is going to be very interesting, bumping the results of the occultation up against the Huygens atmospheric profile - would 'high shear winds' possibly show up as Dopplered patterns in the density distribution?

[djellison]

Yes, but how many of us actually paid to see it in the theater?


- Bob C.

I went to see it - but it wasnt on. I had to put up with Care Bears the Movie instead

I've never been the same since.

Doug

[tedstryk]

I had long wondered what "UNICRON Eats planets for dinner!" means...I vaguely remember Transformers...didn't they fight against the Gobots or something?

[djellison]

The Decepticons were the Transformers enemy if I remember rightly - it was a very long time ago though - back when I lived up in the Wirral and Colour TV was such a novel idea, the BBC2 logo still said Colour under it

Doug

[Decepticon]

Unicron is a Giant Transforming planet. In planet mode he devours worlds in minutes.

He is basically the Transformer version of the Devil.

Wait till the Movie comes out 2007!! Should be a big one!

Does VIMS look at Ontario Lacus?

[Guest_BruceMoomaw_*]

Bah. Galactus should sue him for patent infringement. (Of course, I've always wondered why Marvel Comics didn't sue the pants off George Lucas for ripping off Darth Vader from Dr. Doom.)

[elakdawalla]

My favorite piece of trivia about Unicron, the Planet Eater, is that his voice in the movie is none other than Orson Welles in his last -- yes, his last -- movie. As much as I loved the Transformers growing up I consider that somewhat of a cruelly farcical end for such a distinguished career as Welles'. (Other well-known actors whose voices appear in the film include Leonard Nimoy, Eric Idle, and Robert Stack.)

Yes, but how many of us actually paid to see it in the theater?

I certainly did!

--Emily
(who has always, in her heart, been a Decepticon. Autobots are boring.)

[Guest_BruceMoomaw_*]

My favorite piece of trivia about Unicron, the Planet Eater, is that his voice in the movie is none other than Orson Welles in his last -- yes, his last -- movie. As much as I loved the Transformers growing up I consider that somewhat of a cruelly farcical end for such a distinguished career as Welles'.

Whoever came up with that idea had an eye for cruel in-jokes. (I remember reading a CNN story years ago headlined "Aging Stars Are Eating Planets", and wondering if it referred to Marlon Brando.)

P.S.: As someone who could tell you more about the history of the Justice League of America than you ever wanted to know, I can't tell you how it warms my heart to see someone else on this site dotty enough to 'fess up to being a comics enthusiast. (Of course, a few months back, Univ. of Chicago political scientist Dan Drezner interrupted his sophisticated blog commentary on international politics to gripe about how annoying it had been for him as a kid that Aquaman always had to be rescued by the rest of the Super Friends. This led to one of his most protracted discussion threads.)

[Guest_BruceMoomaw_*]

I went to see it - but it wasn't on. I had to put up with Care Bears the Movie instead

I've never been the same since.

Doug

You have my profoundest sympathies.

-- Queasy Heart Moomaw

[djellison]

who has always, in her heart, been a Decepticon

I KNEW there was something dodgy about you

Doug

[Decepticon]

(who has always, in her heart, been a Decepticon. Autobots are boring.)

Awww Shucks!!

[Guest_AlexBlackwell_*]

P.S.: As someone who could tell you more about the history of the Justice League of America than you ever wanted to know, I can't tell you how it warms my heart to see someone else on this site dotty enough to 'fess up to being a comics enthusiast.

<Gasp> I can't believe this. You mean you and I are both JLA fans? What's next? That're were related?

[Mongo]

Unicron is a Giant Transforming planet. In planet mode he devours worlds in minutes.

He is basically the Transformer version of the Devil.

Wasn't there an episode of Original Star Trek where a neutronium-hulled machine breaks up and consumes planets?

Bill

[Bob Shaw]

<Gasp> I can't believe this. You mean you and I are both JLA fans? What's next? That're were related?

"In darkest day, in deepest night
no Moomaw shall escape Alex' sight!"

Bob Shaw

[Guest_AlexBlackwell_*]

"In darkest day, in deepest night
no Moomaw shall escape Alex' sight!"

BTW, Green Lantern (whose oath you so eruditely paraphrased) is one of my favorites. So, I guess I'm GL and Bruce is Sinestro, huh?

[Bob Shaw]

BTW, Green Lantern (whose oath you so eruditely paraphrased) is one of my favorites. So, I guess I'm GL and Bruce is Sinestro, huh?

Alex:

Wellllll...

Bob Shaw

[Guest_BruceMoomaw_*]

Never forget, Alex, that Sinestro is more powerful. Green Lantern -- as he admitted once -- was "just better at dodging."

(Parenthetically, I really don't know how the League is going to overcome the current Watergate-type scandal connected with the exposure of the fact that they were secretly erasing supervillains' memories and even trying to magically alter their personalities, with disastrous results. The whole situation completely fell apart at that point, culminating with a furious physical brawl between Batman and Green Arrow in which the former called the latter "a second-rate Errol Flynn" and the latter accused the former of fighting crime dressed up like a giant mouse. The whole thing is depressingly reminiscent of the current US administration.)

[Guest_AlexBlackwell_*]

Never forget, Alex, that Sinestro is more powerful. Green Lantern -- as he admitted once -- was "just better at dodging."

Actually, I'm a huge fan of "Silver Age" Green Arrow (see fellow planetary_sciences alum Jayme L. Blaschke's website).

Hey, I'd love to discuss Green Lantern, Green Arrow, Sinestro, JLA, the Secret Society of Super Villains, The Flash and his Rogues Gallery, etc., in more detail here but something tells me this isn't a good idea.

[Guest_AlexBlackwell_*]

Back to the topic: the T12 flyby page is now online.

[Guest_BruceMoomaw_*]

Spoilsport.

[ugordan]

A distant, multispectral ISS Titan sequence is already down.
A crude CB1-GRN-BL1 composite, reduced to 75% original size:

Taken from 1.2 million km, north on Titan is located at approximately 11 o'clock position.

[Decepticon]

Some Raw images are up.

[Bob Shaw]

Never forget, Alex, that Sinestro is more powerful. Green Lantern -- as he admitted once -- was "just better at dodging."

(Parenthetically, I really don't know how the League is going to overcome the current Watergate-type scandal connected with the exposure of the fact that they were secretly erasing supervillains' memories and even trying to magically alter their personalities, with disastrous results. The whole situation completely fell apart at that point, culminating with a furious physical brawl between Batman and Green Arrow in which the former called the latter "a second-rate Errol Flynn" and the latter accused the former of fighting crime dressed up like a giant mouse. The whole thing is depressingly reminiscent of the current US administration.)

Bruce:

Giant mice? Current US Administration?

Did you take the Blue Pill or the Red Pill?

Oh, for some sanity, such as Mr Mxyzpltyx (or however you spell it) used to offer in moments of crisis...

Bob Shaw

[Guest_AlexBlackwell_*]

Oh, for some sanity, such as Mr. Mxyzpltyx (or however you spell it)...

Mr. Mytzlplk.

[Bob Shaw]

Mr. Mytzlplk.

Alex:

If you start trying to persuade Bruce to write the word 'wamooM' anywhere hereabouts then I'll get seriously worried!

wahS boB

[Guest_BruceMoomaw_*]

Fat lot of good you would have done dealing with him, Alex! You misspelled his name!

[dvandorn]

<Gasp> I can't believe this. You mean you and I are both JLA fans? What's next? That're were related?

There are several of us here, I bet. My favorite JLA member was always J'onn J'onzz, the Martian Manhunter. Some of the people who were involved in Mars exploration back in the '60s might have traced their interest back to Edgar Rice Burroughs' John Carter -- but my interest started, when I was five years old or so, from wanting to see where J'onn came from...

-the other Doug

[Guest_BruceMoomaw_*]

There are several of us here, I bet. My favorite JLA member was always J'onn J'onzz, the Martian Manhunter. Some of the people who were involved in Mars exploration back in the '60s might have traced their interest back to Edgar Rice Burroughs' John Carter -- but my interest started, when I was five years old or so, from wanting to see where J'onn came from...

-the other Doug

We're getting awfully far off the subject of Titan T12; but, yeah, I've always been a fan of the Big Green Guy, who strikes me as a more complex, interesting and melancholy version of Superman. DC Comics did an awful lot of squirming around in the 1960s trying to explain how Mars could have intelligent life despite the fact that the probes in our own universe were revealing it to be a desert; they finally declared in 1969 that the planet had been devastated by a world war, and kicked J'onn out of the JLA so that he could lead the survivors to a habitable planet orbiting another star. Since then, they've completely revised his origin twice; the current version is that all the intelligent Martians except J'onn -- including his family -- were wiped out millions of years ago by a telepathic "plague" unleashed by J'onn's Evil Brother (that famous Martian vulnerability to fire turns out to be a psychosomatic disorder, which when you're a shapeshifter can be deadly), and that the Earth scientist who accidentally teleported him to Earth also yanked him millions of years forward through time in the process. He also finally got his own comic book a few years ago -- and, while it shut down, he's about to get another one. Last but not least, we have learned that chocolate is an addictive narcotic for Martians, with the result that J'onn has learned the hard way to stay away from Oreo cookies.

I think maybe we better move this discussion to another website.

[David]

We're getting awfully far off the subject of Titan T12 [...]

I think maybe we better move this discussion to another website.

Oh, this is fun reading. Start a "Martian nostalgia" thread down in Chit Chat or something.

[Phil Stooke]

Back to Titan, you naughty people.

Here's one of the approach images with a bit of fiddling:




Phil

[ugordan]

That Solar System Simulator v4.0 they're using for Cassini's current position sometimes acts really funny.
Take this image for example:


What's wrong with this? It shows Titan after C/A and there's Saturn in the background (?). They should obviously be on different sides of the spacecraft as this is an inbound flyby.
I've seen similar examples before - Earth being occulted by the rings for example, when the rings are nowhere near in other views, whole Saturn disappearing etc.

[Thorsten]

Some Raw images are up.

Raw images from T12 are up, including some truly beautiful views on Vis, Santorini and Guabonito! They really look a lot like impact craters, partially buried by the sands of Shangri-La.

http://saturn.jpl.nasa.gov/multimedia/imag...9/N00055275.jpg

http://saturn.jpl.nasa.gov/multimedia/imag...9/N00055297.jpg

http://saturn.jpl.nasa.gov/multimedia/imag...9/N00055319.jpg

[Guest_AlexBlackwell_*]

For RSS fans, below is an excerpt from today's Cassini Significant Events Report. I've also seen some of the T12 RSS ionospheric data that the team plans to present at the upcoming EGU General Assembly 2006; it looks very clean.

On March 18 the Cassini spacecraft conducted the 13th targeted flyby of Saturn's moon Titan. With a closest approach altitude of 1,951 km, this flyby provided the first Cassini tour opportunity for Radio Science (RSS) to observe Titan's ionosphere and neutral atmosphere using radio occultation, and Titan's surface using bistatic scattering. The radio occultation is the second ever of Titan, the first being a sole Voyager occultation in 1980.

During approach to Titan, the Cassini high gain antenna boresight was pointed to illuminate regions of Titan's surface for which mirror-like reflections of the incident radio signals can be observed at the DSN ground receiving stations. The strength and polarization properties of the reflected signals, if detectable, provide important information about the physical nature of the surface region probed, as well as the surface roughness.

Radio Science has reported that the S- and X-band data is of exceptionally high quality. Both the large and small-scale structure of the atmosphere at the two observation latitudes are well captured in the data. The data is consistent among the multiple stations observing at the same time, clearly indicating that the structure observed is real and not noise. The details of the small-scale structure appear to be different for the ingress and egress sides. Despite spacecraft pointing being controlled by thrusters and poor weather at both Goldstone and Madrid at the time, the Ka-band amplitude stability appears to remain surprisingly good throughout the approximately one hour observation period.

All indications are that T12 was remarkably successful, the first Titan occultation in 25 years, the first at three wavelengths, and the first Titan bistatic experiment as well.

[angel1801]

For RSS fans, below is an excerpt from today's Cassini Significant Events Report. I've also seen some of the T12 RSS ionospheric data that the team plans to present at the upcoming EGU General Assembly 2006; it looks very clean.

I did read about Voyager 2 bouncing signals off Titan on June 4, 1989 (three and half months before Neptune C/A) and finding (from the limited data run) that Titan had no lakes and a hard surface.

[The Messenger]

For RSS fans, below is an excerpt from today's Cassini Significant Events Report. I've also seen some of the T12 RSS ionospheric data that the team plans to present at the upcoming EGU General Assembly 2006; it looks very clean.

Yayha!

(That's a politically correct whooopie!)

It is exciting that they plan to report this so soon!

Is anyone going to be there?

[tedstryk]

I did read about Voyager 2 bouncing signals off Titan on June 4, 1989 (three and half months before Neptune C/A) and finding (from the limited data run) that Titan had no lakes and a hard surface.

Are you sure that wasn't Triton?

[Phil Stooke]

And that it was 3.5 months before C/A? This doesn't sound right! As for Titan, Voyager 2 didn't do a close Titan flyby.

Phil

[angel1801]

And that it was 3.5 months before C/A? This doesn't sound right! As for Titan, Voyager 2 didn't do a close Titan flyby.

Phil

I'm sure it was Titan. I remember the article well and it did say Titan not Triton. Use a Google search to find it.

[Holder of the Tw...]

I'm sure it was Titan. I remember the article well and it did say Titan not Triton. Use a Google search to find it.

If the article said that, the article was wrong. Three and a half months from Neptune puts you a couple billion miles from Titan. The only bistatic experiment I (sort of) remember from the Voyagers was to bounce radio off the rings. And that's a whole lot bigger target than Titan.

[JRehling]

I did read about Voyager 2 bouncing signals off Titan on June 4, 1989 (three and half months before Neptune C/A) and finding (from the limited data run) that Titan had no lakes and a hard surface.

A radar experiment that bounced radar off of Titan did take place in 1989, but the source was the DSN dish at Goldstone (on Earth!), not Voyager 2. Voyager 2 was, in 1989, farther from Titan than the Earth ever is! A satellite in low Earth orbit would have been better positioned to do the study then than Voyager 2!

http://www.aoc.nrao.edu/~bbutler/work/titan/DPS04.html

[angel1801]

A radar experiment that bounced radar off of Titan did take place in 1989, but the source was the DSN dish at Goldstone (on Earth!), not Voyager 2. Voyager 2 was, in 1989, farther from Titan than the Earth ever is! A satellite in low Earth orbit would have been better positioned to do the study then than Voyager 2!

http://www.aoc.nrao.edu/~bbutler/work/titan/DPS04.html

I was still partially right. I just got the Voyager 2 and Goldstone thing wrong. Still, the outcome was that (given the very limited run) that Titan lacked oceans and had a rock hard surface. The reason that this never got mentioned is probably due to events in China on that very same day!

[hendric]

Back to Titan, you naughty people.

Here's one of the approach images with a bit of fiddling:




Phil

I hereby dub thee "T. Rex!"



Raarrgh!

[The Messenger]

A radar experiment that bounced radar off of Titan did take place in 1989, but the source was the DSN dish at Goldstone (on Earth!), not Voyager 2. Voyager 2 was, in 1989, farther from Titan than the Earth ever is! A satellite in low Earth orbit would have been better positioned to do the study then than Voyager 2!

http://www.aoc.nrao.edu/~bbutler/work/titan/DPS04.html

Interesting.

The paper makes it quite clear that we should have expected a primarily hard or icy surface. The lake idea is purely a support mechanism for the methane in the atmosphere, which, especially after observing the vents of Enceladus, we should be looking for vent sources as well as pools. Or do we need either? A surface of fine particles has oddles of surface area, that could easily be saturated with hydrocarbons - we know this was the case, where Huygens landed. And we have visual of the dunes. Is the spectral signature of Titan consistent with sand saturated with light hydrocarbons?