Cassini Equinox & Solstice Mission, (nine year extension)!!.

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3488

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Re: Cassini Equinox Mission (Cassini's two year extension).

Should be a fascinating encounter. The ISS should obtained high res IR imagery from the high southern latitudes to the equator & there should be further atmosphric observations, searching for clouds, particularly in the high southern latitudes.

Following on from the Prometheus encounter, Cassini passed approx 45,000 KM of the 1,123 KM wide differentiated moon Dione. Dione is certainly one of Saturn's most interesting moons.

Whilst cratered, there are signs of large & prolonged tectonic activity & that Dione may have spun around a full 180 degrees in fairly recent geological times (based on cratering densities, the leading hemisphere usually is heavily cratered & that side meets impactors head on. Dione's TRAILING side is the more heavily cratered side).

This pass allowed for some of the best imagery to date of the north polar region of Dione.

Below a few Dione images I have worked on.












Andrew Brown.
 
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3488

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Re: Cassini Equinox Mission (Cassini's two year extension).

First imagery from the Titan T66 (Route 66) encounter on Thursday 28th January 2010. EarthlingX has provided a link, two posts up.




This was taken from approx 345,000 KM about the same as from the Earth to the Moon. I guess that is the Belet & Shangri La Regions, a vast 'sand sea' with what appears to be tectonic features on the far right.


Steller Occultation experiment, showing stars pass behind Titan's atmosphere (the vastly over exposed limb of Titan is visible on the left).


Andrew Brown.
 
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nimbus

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Re: Cassini Equinox Mission (Cassini's two year extension).

That veil directly to the right of Titan's limb is its outer atmosphere?
 
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3488

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Re: Cassini Equinox Mission (Cassini's two year extension).

Hi nimbus, it is indeed.

The steller occultation experiment allows Cassini to observe changes in the known star's spectra as it passes behind Titan's atmosphere to guage absorbtion & compositional data as well as density & temperature profiles over differing latitudes in Titan's atmosphere.

The data from this pass will be essential towards this end.

Andrew Brown.
 
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nimbus

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Re: Cassini Equinox Mission (Cassini's two year extension).

Thank you.
 
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3488

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Re: Cassini Equinox Mission (Cassini's two year extension).

You are very welcome nimbus.

I absolutely love this, please continue to ask away. :mrgreen:

An IR view of a gibbous Titan taken from approx 708,000 KM during the T66 (Route 66) pass. I have contrast enhanced it considerably to bring out more detail.


Below a blue filter image I have cropped of Titan's arctic area, showing detached hazes in the early Spring Stratosphere of Titan.


Whilst this pass was considerably further than most targetted encounters of this planet giant sized moon (second only to Jupiter's Ganymede), the pass was dedicated to Titanian atmospheric studies possibly yielding the best results since the descent of the ESA Huygens back in January 2005.

It has been a fascinating week for Cassini.

The closest pass yet of the F Ring moon Prometheus, yielding the sharpest images yet of that strange potato shaped worldlet, followed by a very good mid range pass of Dione, showing us areas clearly that were not well seen before of that fascinating evolved moon & now a unique set of observations made of Titan.

Andrew Brown.
 
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EarthlingX

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Re: Cassini Equinox Mission (Cassini's two year extension).

More fascinating years ahead:
NASA Extends Cassini's Tour of Saturn
(PhysOrg.com) -- NASA will extend the international Cassini-Huygens mission to explore Saturn and its moons to 2017. The agency's fiscal year 2011 budget provides a $60 million per year extension for continued study of the ringed planet.
 
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MeteorWayne

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Re: Cassini Equinox Mission (Cassini's two year extension).

That's expected, but very good news.

Thanx!!
 
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EarthlingX

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Re: Cassini Equinox Mission (Cassini's two year extension).

MeteorWayne":jj214v1s said:
That's expected, but very good news.

Thanx!!
It was a definite pleasure :)

A complete seasonal period on Saturn has never been studied at this level of detail. The Solstice mission schedule calls for an additional 155 orbits around the planet, 54 flybys of Titan and 11 flybys of the icy moon Enceladus.

The mission extension also will allow scientists to continue observations of Saturn's rings and the magnetic bubble around the planet known as the magnetosphere. The spacecraft will make repeated dives between Saturn and its rings to obtain in depth knowledge of the gas giant. During these dives, the spacecraft will study the internal structure of Saturn, its magnetic fluctuations and ring mass.
Lovely :)
 
3

3488

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Re: Cassini Equinox Mission (Cassini's two year extension).

Yes indeed, it is superb news.

I have just been reading up on this major mission extension.

56 close passes of Titan, 12 of Enceladus, 4 of Dione, 2 of Tethys & 1 each of Rhea, Epimetheus, Methone & Telesto.

The final close Titan encounter reduces Cassini's perikrone to only 3,600 KM above Saturn's stormy cloudtops, (3D imaging of the clouds should be possible as will many magnetometer & radiation measurements will be made).

The final close Titan pass on Saturday 22nd April 2017, Cassini's perikrone leaps from just outside Saturn's rings to between the rings & Saturn itself, with 23 close perikrones.

With Cassini passing between Saturn & the ring system, more precise measurements of the mass of the ring sytem will be possible by precise tracking of Cassini measuring the slight tug on the spacecraft by it's gravity.

There will be 23 such low perikrones, with the final distant Titan pass on: Monday 11th September 2017, setting Cassini on a course to enter Saturn's atmosphere on: Friday 15th September 2017.

The Northern Saturn Summer Solstice occurs in May 2017, so the extended mission will see Cassini operate well beyond the Kronian Solstice.

Andrew Brown.
 
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clint_dreamer

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Re: Cassini Equinox Mission (Cassini's two year extension).

That final year sounds very exciting and should provide many breathtaking pictures before Cassini's demise.

I love this spacecraft. Keep up the excellent work!
 
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3488

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Re: Cassini Equinox Mission (Cassini's two year extension).

I agree Clint. Lets hope that Cassini continues to operate well, right up to September 2017.

It'll be worth mentioning that by then Cassini will have been in space for only a month shy of 20 years (launched October 1997), so of course we cannot guarfantee that Cassini will complete the Solstice Mission successfully, though I think chances are good to excellent that she will.

Often I look at stuff returned retrospectively & have worked on a few interesting Rhea images that were returned by Cassini back on: Saturday 21st November 2009, during the mid range pass on that date.

Below a nice gibbous Rhea, an image that has not released anywhere AFAIK other than the raw image directory.


An area approx 60 KM accross that I have sharpened & enlarged, showing the general rolling cratered landscape, that is fairly typical of Saturn's second largest moon.


An area approx 80 KM accross that I have sharpened & enlarged, that clearly shows thrust faulting, something not expected on a body considered to be undifferentiated, unless associated with the Tirawa Impact event.


Two areas approx 100 KM accross that I have sharpened & enlarged, that clearly shows thrust faulting, something not expected on a body considered to be undifferentiated, unless associated with the Tirawa Impact event.




An area approx 140 KM across on Rhea that I have sharpened & enlarged, that appears to look like a cryocaldera with a faulting system enamating from it. Myself I think the depression is an impact crater, that had formed over faults.


Andrew Brown.
 
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EarthlingX

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Re: Cassini Equinox Mission (Cassini's two year extension).

Thank you 3488 for more pictures for my screensaver :D
This one jumped at me, don't know exactly from when, i just like it, and i hope you will too:
Saturn and Rhea:

It's probably on the Cassini site ..

Oh, and this is a nice read too:
Tirawa (god)
Pawnee mythology is the body of myths and legends belonging to the Pawnee concerning their gods and heroes. The Pawnee are a federally recognized tribe of Native Americans, originally located along tributaries of the Missouri River.
And since i started with this, let me finish with:
Tirawa (crater)

and a question:
Why are those walls so smooth ? They remind me of a crater on Hyperion (One of the weirdest moons in my book).
 
3

3488

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Re: Cassini Equinox Mission (Cassini's two year extension).

Hi EarthlingX.

That fantastic image you posted up was obtained: Sunday 4th February 2007, just over three years ago.

Hyperion, a strange little world indeed. Apparently the least dense non gaseous body in the solar system. Saturn the lesat dense planet having the least dense known moon @ only 0.55 GM3.

Hyperion. 280 KM long.


'Crescent' Hyperion.


Hyperion cliff, approx 15 KM high.


Hyperion weird cratered terminator, with unusually deep craters.


Then two extreme close ups. One even shows boulders on Hyperion.




Andrew Brown.
 
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EarthlingX

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Re: Cassini Equinox Mission (Cassini's two year extension).

Thank you :D
I updated the file name on my disk, and i like your naming standard ;) ..
 
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EarthlingX

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Re: Cassini Equinox Mission (Cassini's two year extension).

Water on Enceladus:
Saturn's Moon Does Harbor an Ocean, New Evidence Suggests
www.space.com":32nwepsz said:
By Jeremy Hsu
Special to SPACE.com
posted: 09 February 2010
10:35 am ET

Icy plumes of water vapor erupting from Saturn's moon Enceladus have left scientists divided over whether a liquid ocean lies hidden beneath the icy surface. Now evidence from a 2008 plume fly-through by NASA's Cassini spacecraft has turned up short-lived water ions that suggest liquid water does indeed exist inside the moon.
Saturn’s Rings Have Gone Plaid
http://www.universetoday.com[/url]":32nwepsz]
February 9th, 2010
Written by Nancy Atkinson
Are Saturn’s rings spinning at ludicrous speeds? It appears they have gone plaid! The Cassini spacecraft has actually spied two types of waves in Saturn’s A ring: a spiral density wave on the left of the image and a more pronounced spiral bending wave near the middle. And the “plaid” look comes from the slight pixelation visible near the brightest and darkest lines, which the Cassini team says is an unavoidable result of the size of the camera’s sensor and of image processing.


Plaid :?
Memorable quotes for Spaceballs (1987)
www.imdb.com":32nwepsz said:
Barf: [Spaceball 1 roars by them, in a plaid colouration of speed] Aah!
Barf: What the hell was that?
Lonestar: Spaceball 1.
Barf: They've gone to plaid!
 
3

3488

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Re: Cassini Equinox Mission (Cassini's two year extension).

Just a quick chime in as my home computer has crashed.

On Saturday Cassini made observations of Calypso.

Saturn moon Calypso. Tehtys trailing co orbital.




Saturn nightside & rings.


Andrew Brown.
 
3

3488

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Re: Cassini Equinox Mission (Cassini's two year extension).

Mimas with Herschel Crater. Imaged on: Saturday 13th February 2010.







Another nice Mimas image from approx 72,000 KM. Using the UV filter.


Another view of the Herschel Crater.


Enlarged sharpened crop of the central mountain in the Herschel Crater on Mimas.


Enlarged & sharpened crop of Section of Herschel Crater wall & floor on Mimas. What is immediately obvious is the lack of small craters on the floor of Herschel Crater. Landslide debris covering the original floor perhaps? Or is Herschel Crater fairly young?


Regarding Mimas, does look like crater slumping has occured.

Another enlarged crop of the rim of Herschel Crater. It is quite apparant that material has slumped & striations visible on the crater wall.


Below, two enlarged crops of the limb of Mimas I did. I rotated them so they look like an horizon. Both crops are approx 30 KM wide & have been contrast enhanced. Looks almost like a view as if coming in to land!!!! Some of those mountains are approx 2,000 - 3,000 metres high IMO.




Just been toying around with a few Mimas images, a few sharpened, enlarged crops.

The 130 KM wide, 5 KM deep Herschel Crater crop during approach. It is worth bearing in mind that Mimas is only 395 KM across.


Mimas. NE of Herschel Crater rim & a curious depression.

Mimas. Northern Rim of Herschel Crater & area north. Impact melt appears to have smoothed much of the terrain.


Curious Depression on Mimas to the N E of Herschel Crater. Feature is approx 100 KM long N - S.


Mimas. Southern portion of Herschel Crater with elliptical secondaries & valleys radiating away outside to the south. The crater on the bottom right of this cropped frame also has had landslides.


Mimas. SW floor of Herschel Crater. The base of the central mountain is visible in the top right. Note how few small craters are visible here. This is quite a surpise assuming Herschel Crater is ancient.


NW limb of Mimas, showing the very cratered & rough terrain on this ice moon of Saturn.


SW limb of Mimas. Some of these larger craters appear to have been formed from double impactors?? Wayne, what do you think? Some of these craters show striations on their walls.


Andrew Brown.
 
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EarthlingX

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Re: Cassini Equinox Mission (Cassini's two year extension).

Mmm... :p
 
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3488

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Re: Cassini Equinox Mission (Cassini's two year extension).

A quick enlargement of the 21 KM long Tethys trailling moon Calypso. Will be pleased when I get my own computer back though. The icy rubble surface is clearly visible along with either icy outcrops & / or ice blocks.


Andrew Brown.
 
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MeteorWayne

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Re: Cassini Equinox Mission (Cassini's two year extension).

"A quick enlargement of the 21 KM long Tethys trailling moon Calypso."

Wow, a noticeable lack of small craters on that potato!!
 
3

3488

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Re: Cassini Equinox Mission (Cassini's two year extension).

Greats points both Wayne.

I have not really properly looked at these yet as I do not have much time to do so until I get my own computer back.

Regarding craters on Calypso, I also noticed that the leading & larger Tethys co-orbital moon Telesto, is also devoid of small craters & also has an icy equivalant of regolith covering the surface. Calypso & Telesto are remarkably similar in this respect.

Yes that valley on the terminator of Calypso is very interesting too. When I get my computer back after repairs, I will do a major enlargement of the terminator of Calypso & really sharpen it up. It does look erosional, though I suspect it is not, being a small airless body only 21 KM long. A glancing impact? Fracture?

A quick enlargement of the 21 KM long Tethys trailling moon Calypso. Will be pleased when I get my own computer back though. The icy rubble surface is clearly visible along with iether icy outcrops & / or ice blocks.


Another view of 21 KM long Calypso slightly further away & from a slightly different angle.


Also these quick cropped enlargements. Saturn moon Epimetheus passing in front of Janus.








Andrew Brown.
 
3

3488

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Re: Cassini Equinox Mission (Cassini's two year extension).

Cassini also performed a non targetted pass of Tethys on: Saturday 13th February 2010, after the Mimas & Calypso observations.


A couple of quick crops.

Odysseus Crater.


Limb view showing a rugged topography, showing a transition from rougher to smoother terrain, cryovolcanism perhaps?? How does that fit with a body considered to be undifferentiated? Refrozen ice from impact melt perhaps??


Andrew Brown.
 
3

3488

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Re: Cassini Equinox Mission (Cassini's two year extension).

Got my computer back, got my software loaded back on.

Sharpened enlargement of the trailling Tethys Trojan moon the 21 KM wide Calypso.


As promised or threatened earlier, I have enlarged & sharpened the terminator of Calypso. The area shown is approx 10 KM across.


Enlarged sharpened crop of the 'snout' of Calypso, showing what appears to be a partially 'buried' crater or ice blocks. As Wayne said before, there appear to be a lack of small craters.


Andrew Brown.
 
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