CICLOPS: Cassini Imaging Central Laboratory for OPerationS

Coming to Light
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As seasons change on Saturn, and sunlight creeps farther north, the region surrounding the north pole is steadily coming to light.

This scene reveals many features in Saturn's dynamic and beautiful atmosphere, including a detail largely obscured from the imaging cameras until now. On the terminator at center right is part of the polar hexagon, which was previously observed by Cassini's Visible and Infrared Mapping Spectrometer (VIMS) and Composite Infrared Spectrometer (CIRS). These instruments used heat radiated from Saturn to observe the polar hexagon (rather than reflected sunlight, as is the case in this view). The hexagon was first imaged by the Voyager spacecraft more than 25 years ago.

The view looks toward the unilluminated side of the rings from about 38 degrees above the ringplane and is centered on a region 63 degrees north of the Saturnian equator.

The image has been brightened to show details at high northern latitudes, where solar illumination is presently weak.

The image was taken with the Cassini spacecraft wide-angle camera on Jan. 2, 2008 using a combination of spectral filters sensitive to wavelengths of polarized infrared light centered at 752 and 705 nanometers. The view was acquired at a distance of approximately 930,000 kilometers (578,000 miles) from Saturn. Image scale is 52 kilometers (32 miles) per pixel.

The Cassini-Huygens mission is a cooperative project of NASA, the European Space Agency and the Italian Space Agency. The Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, manages the Cassini-Huygens mission for NASA's Science Mission Directorate, Washington, D.C. The imaging team consists of scientists from the US, England, France, and Germany. The imaging operations center and team lead (Dr. C. Porco) are based at the Space Science Institute in Boulder, Colo.

For more information about the Cassini-Huygens mission, visit http://saturn.jpl.nasa.gov and the Cassini imaging team home page, http://ciclops.org.

Credit: NASA/JPL/Space Science Institute
Released: February 1, 2008 (PIA 09828)
Image/Caption Information
  Coming to Light
PIA 09828

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Alliance Member Comments
Red_dragon (Apr 17, 2008 at 6:50 AM):
:). You'll never guess where i got that of "Supreme Explorer" from. Keep up the good work!
carolyn (CICLOPS) (Apr 16, 2008 at 8:28 AM):
And you know what? We will give you more! Stay tuned for a lot of it.
toomanytribbles (Apr 16, 2008 at 5:18 AM):
u-huh... but you know what that means... we want more!
carolyn (CICLOPS) (Apr 16, 2008 at 4:51 AM):
Yes! We have been given at least another two years of exploits around Saturn to continue our mission ... our reward for a phenomenally successful exploratory expedition. Our `Supreme Explorer' lives on! Needless to say, we are pleased.
Red_dragon (Apr 16, 2008 at 3:26 AM):
CONFIRMED: NASA has approved Cassini's extended mission (http://saturn.jpl.nasa.gov/news/press-release-details.cfm?newsID=833).
At least two more years of science and odyssey at Saturn if everything goes well.
Red_dragon (Feb 29, 2008 at 7:25 AM):
Remember some mass media just want sensationalism. If -just as an example- Cassini during a Titan flyby found there geological structures that look like runways, surely they would say "Cassini finds titanian runways", not just natural structures that look as that. Also, (very) little damage could do Cassini to something so huge as Saturn (think on what we've done to our planet and it's still around...for now).

About the extended mission, I believed it had been approved -you can even see what is in store for her here: http://saturn.jpl.nasa.gov/operations/index.cfm, although, yes, it's stated there the official approval is pending-.

I hope that there'll be that approval, and luckily will be still many years of Cassini mission: that magnificent spacecraft that's undoubtely and at least for now the "Supreme Explorer", certainly deserves it.
Mercury_3488 (Feb 27, 2008 at 5:24 PM):
Hi DEChengst,

I agree with you about the nonsense regarding the Plutonium issue regarding Galileo & Jupiter. I was aware of certain elements against that plan for the fear of Jupiter becoming a second Sun due to Galileo's RTG.

It was total nonsense back then as it is nonsense that Cassini will do that with Saturn.

Gort asked a good question as he / she was not probably not aware of the non issue involved, perhaps heard scare stories from somewhere.

I responded saying that Cassini cannot initiate thermonuclear synthesis within Saturn. Cassini will not last more than seconds after atmospheric entry, will be incinerated as a shooting star in Saturn's highest atmosphere.

I was aware that Pu238 is the wrong isotope for nuclear fission. It is the heat from its natural decay that is powering Cassini. It is not even a nuclear reaction at all & that the RTGs are NOT nuclear reactors.

Remember the nonsense about the campaign to abandon the Earth encounter post launch, due to unjustified panicking over Cassini re entering Earth's atmosphere

Thanks Carolyn,

I was not aware that even the first mission extension was not yet approved. I am sure & hope that it will be granted. The second one should also.

I agree with you 100%, that the Kronian Solstices would be of very scientific value, if Cassini is still operational & controllable then.

Like the recent Janus & Titan images. Although still iregular in shape, Janus appears more 'regular' than co-orbital / orbital swap mate Epimetheus. Wonder if Janus's larger size & mass are responsible.

Primary mission still up & Cassini still performs as well as when had just arrived. I am sure mission extension will happen.

Andrew Brown.
DEChengst (Feb 27, 2008 at 1:24 PM):
"And regarding the plutonium/hydrogen issue, I fail to see the connection. Why would a radioactive source pose any danger for a hydrogen atmosphere?"

It's the same nonsense we heard when Galileo was flown into Jupiter. People somehow assume that the Pu238 in the RTGs will become a fission bomb and will reach high enough temperature to achieve hydrogen fusion. That the Pu is the wrong isotope to make a bomb is the first thing they fail to understand. Their line of reasoning only goes downhill from there if you ask me.
carolyn (CICLOPS) (Feb 26, 2008 at 2:58 PM):
Andrew and Gort,

First, there has been no official approval of even the first extended mission...out to the summer of 2010...though it is a near certainty. Regarding the 2nd extension, it is only in the preliminary stages of discussion...a mere glimmer in the eye, so to speak. The Cassini Project believes that a very worthy and scientifically justifiable goal is the northern summer solstice, which would be about 2017. Then we will have been at Saturn for nearly half a Saturn year, with the opportunity to monitor seasonal changes in the atmospheres of Saturn and Titan, surface changes on Titan (especially the lakes in the polar regions), geysering activity on Enceladus, dynamics in the rings, etc. But we haven't even yet proposed this officially to NASA.

And regarding the plutonium/hydrogen issue, I fail to see the connection. Why would a radioactive source pose any danger for a hydrogen atmosphere?
Gort (Feb 26, 2008 at 2:19 PM):
Thanks, Andrew.

(But all it takes is one match to start a forest fire, according to Smokey the Bear... you'll have to Google that if you aren't from the US :-)

My understanding is that Cassini contains more than a few Kg of Plutonium Dioxide ... Perhaps as much as 40 Kg. Does the Plutonium become less reactive over time as it's used to provide energy for the probe?

Carolyn ... if you are monitoring, is this correct? I'd be interested to learn what the official consensus is on the topic.

Thanks,
-Gort
Mercury_3488 (Feb 24, 2008 at 3:00 PM):
Hi Gort,

Welcome to our Alliance.

I would not worry about the Plutonium.

Firstly if you are worried about the Plutonium creating a Hydrogen bomb out of Saturn, no worry. We are dealing with only a few KG of Plutonium, against Saturn's trillions & trillions of tons of Hydrogen.

Secondly, Cassini will not penetrate far at all. The Cassini Spacecraft will be vapourized as a meteor soon after entry into Saturn's atmosphere, in the Ionosphere, will not even reach Saturn's Stratosphere, well above the clouds.

By the way Cassini is performing, I really think 2017 will be possible at the Saturn system northern Summer / southern Winter Solstice. Will try & find the actual date. For Titan will be about four months earlier.

Andrew Brown.
Gort (Feb 24, 2008 at 5:52 AM):
Hello,

I just joined Sector 6 to keep abreast of the rest of the Cassini mission, and observed Carolyn's comment about the approved extended mission.

Has the ending date been fixed? I saw 2010 and then 2017 as potential years.

I am concerned about a possible reaction between the probe's atomic energy source and the extremely dense hydrogen on Saturn (or Jupiter). How fast would the probe be traveling when it hits the planet, and how deep will it penetrate?

Thanks,
-Gort

Mercury_3488 (Feb 17, 2008 at 11:34 AM):
Once again thank you very much Carolyn,

It is not easy living with my condition. Mostly it is the fear of keeping up my lifestyle without falling to dependence & the fear of unexpected situations rearing up. In other words, I'm often living on my nerves.

Enough about my foibles,

I am very happy to have been acepted so readily into the Alliance. Thank you all very much. Just hope that I can contribute effectively.

The Enceladus post equinox encounters will show if the southern polar 'tiger stripes' will remain active. If not then we can say categorically that the cryvolcanism on Enceladus is solar driven, like Neptune's Triton or even like a gigantic comet.

I suspect though, that will not be the case. I suspect the 'tiger stripes' are permanently active, with tidal flexing generating frictional heat within those faults. I suspect a similar thing is happening on a much lesser degree on Dione & the Uranus moon Ariel.

I doubt that Enceladus would contain enough radioisotopes to generate the necessary heating. So I do suspect it is tidally induced.

I also hope we get to SAR most of Titan with this plan & still get to have at least one more very close Dione encounter, though I can see why Titan & Enceladus would get first pickings.

Andrew Brown.
carolyn (CICLOPS) (Feb 17, 2008 at 10:27 AM):
The orbit I describe would be highly inclined (and so therefore more or less `polar'). It is in fact being called Juno-like. And I can assure you: you will see many more encounters with Titan and Enceladus ... probably the two moons that would win in the contest for Most Captivating!

And good for you ... that you showed them all what you could do. Congratulations! And we're very glad to have you be a member of our Alliance.
Mercury_3488 (Feb 17, 2008 at 10:20 AM):
Once again, thank you very much Carolyn.

3488 is strange, I agree completely 100% with you. No secret I'm happy to explain. Due to my troubled youth with my condition (High Functioning Autistic), it was thought that I could never live outside of sheltered housing.

Well I proved them all wrong. Got my own flat & 3488 was my first ever PIN for my bank account, so that number has real significance.

Not only that it is easy to remember & as there is no other 3488 on any message board on the web, I am easy to find.

Back to Sector 6.

I like the idea of placing Cassini inside of the D Ring. A variant if possible, could Cassini be placed into a very close polar orbit around Saturn?

Twice each orbit the rings would be approached very closely, enabling high resolution imaging, both back & front, whilst global weather monitoring would be doable.

A bit like the JUNO mission to Jupiter & would be able to compare JUNO results directly with Saturn.

I still aim for the Northern Summer Solstice though with the mission carrying on as is. Hopefully we will still get many more Titan, Enceladus & Dione encounters in. Shame we cannot revisit Iapetus & Phoebe due to DeltaV issues (it would be scientifically very valuable to encounter ex KBO Phoebe again, but with the opposite side facing Cassini at closest approach).

Are we likely to get a very close encounter with Mimas & / or Janus, Prometheus, the Dione & Tethys co-orbitals?

It is great talking with you.

Andrew Brown.
carolyn (CICLOPS) (Feb 17, 2008 at 9:47 AM):
3488 (...interesting name, that), We are definitely considering a scientifically useful end to Cassini. At the moment, the ending that seems to have the most enthusiastic support is one that puts Cassini on a trajectory that takes it interior to the D ring for several (or even many) orbits before being sent into Saturn's atmosphere. This will benefit the measurement of Saturn's gravity field, as well as give us wonderful opportunities to image the rings at high resolution. And it would require too much Delta V to put Cassini in an orbit around Titan. We do, after all, want this mission to last until Northern Summer Solstice!
Mercury_3488 (Feb 16, 2008 at 8:22 AM):
Hi Carolyn,

Thank you very much, I did wonder if Iapetus would require too much DeltaV? I know it is early days yet (Cassini has still got years left), but a USEFULLY scientific end to Cassini's mission in my opinion is justifiable.

Instead of just sending Cassini into Saturn (unless it is a day side approach with images being taken & transmitted in real time of the kronian weather systems), I still say an impact on one of the moons would be far more useful.

Dione or Hyperion perhaps? Images being taken & transmitted in real time, remeber the NEAR / Shoemaker landing on asteroid 433 Eros?

Or a complete radar mapping of Titan, with Cassini entering a polar orbit around the giant hazy moon & SAR the entire globe, like Magellan did with Venus?

I know, it is just ideas, but this board allows for ideas to be shared, how unlikely or likely they are to succeed.

Unfortunately, this is something that we all here on at the CICLOPS Alliance, who care so much about this mission will have to face one day with Cassini.

I admit, I was so upset when the Galileo mission ended, Cassini will be no different.

Andrew Brown.
carolyn (CICLOPS) (Feb 14, 2008 at 5:12 PM):
Iapetus requires a lot of energy to reach, and crashing into Iapetus is not being considered for an end of life scenario.

Chances are good we will put the s/c into Saturn but this has yet to be decided.
Mercury_3488 (Feb 14, 2008 at 2:03 PM):
Wow thanks Carolyn.

Did not realise that Cassini could still be operating for SO long. When Cassini looks like the end is coming, could we impact the spacecraft on Cassini Regio on Iapetus?

Reasoning, being that a fututre Saturn / Titan mission could pass close by to Iapetus & image the impact crater to see how quickly that dark brown 'crud' darkens the freshly exposed ice.

Also Cassini could take images & transmit them during the approach. Just an idea.
carolyn (CICLOPS) (Feb 10, 2008 at 10:10 AM):
We have planned an extended mission, with lots of imaging sequences, to go out to the middle of 2010, and the equinox period is a special one ... both for seasonal effects on Titan and solar illumination effects on the rings. And we are now talking about a further extension to Cassini, possibly to the Northern summer solstice in 2017. But we'll see if any of this gets official approval ...
Red_dragon (Feb 8, 2008 at 2:40 AM):
I agree with bruno.thiery .Great image, perhaps the most beautiful of the ones you've posted during this year.
Also, nice comment the one of 3488; Let's hope that Cassini will be still around for that epoch -after all, Galileo survived during eight years in the hellish Jovian environment-.
Mercury_3488 (Feb 6, 2008 at 8:25 PM):
Also these observations are important regarding the meterology of Saturn in the far north. The northern Spring Equinox on Saturn is in December 2009 & Titan's will be in August 2009. The four month difference being due to Titan's very slightly inclined orbit, hense the equinox for Titan is four month's earlier than Saturn's itself.

Whether or not Cassini will still be operational, so long after the end of the primary mission, remains unknown, but in the meantime, it will be interesting to see how the far northern latitudes respond to the change from Winter to Spring.

How long before the orange clouds reform in the north polar region, as the cooling effect of the shadow of the rings wane, etc. Will more storms form, this will tell how much they are effected by solar radiation (only about 10 watts per square metre), verses internal heat.

Likewise important to see how the far southern latitudes respond to Summer turning to Autumn. Will the cooling effect of the ring shadows, turn much of the southern hemisphere blue??

bruno.thiery (Feb 3, 2008 at 4:21 AM):
The magnificence of these whirlpools and arabesques, magnified by the shadow cast by the low-lying Sun, is a pleasure to the eye. With the rings in the background, it is almost too perfect!
Looking at these pictures makes me understand at last why some people enjoy so much abstract paintings.

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