It would also be horrible PR to pull the plug on a fully functional mission simply due to budgets.

Oh it will surely happen - there's the definitive proof of the Rhea rings to confirm yet, the further radar coverage of Titan, the incomparable PR generated by the 'proximal orbits' and so on.
A saturn orbiter is surely priceless.

There's nothing to confirm just yet. There is no discovery, only tantalizing hints and from what I've seen in various ISS observations apparently targeted at imaging the rings, that's going to be a very tough nut to crack. Not sure how other instruments would be able to nail the case. Would RADAR be able to get any reflection from a few boulders some thousands of km away?

The evidence is from particle and fields data (MIMI), not ISS. There is something there, the question is what that something is.

I realize where the claim comes from. Didn't the same instrument pick up hints of activity on Dione? Highly suggestive and tantalizing stuff, but I wouldn't exactly call it evidence by itself. Yes, there definitely appears to be something there around Rhea, but we have no proof it's rings, hence my comment about confirmation with other instruments.

The broad electron depletion seen by MIMI in 2005 can apparently be explained by a broad disk of debris orbiting Rhea; further narrow dropouts on either side of the moon suggested that discrete rings could be embedded in a more diffuse disk. CAPS also saw a similar broad decrease during a more distant flyby in 2007; both the flybys were downstream, so not providing the full picture of the plasma-moon/debris interaction. The next close Rhea flyby's little over a month away on March 2nd; inbound slightly downstream of Rhea in the plasma flow, outbound slightly upstream - maybe we'll get a better picture of what's going on there from those observations.

Hints of activity at Dione came from the magnetometer data, and some have interpreted features seen by CAPS as being signs of plasma release at Dione and Tethys.

The magnetometer did not actually pick up hints of activity at Dione. It has detected a field deformation that could occur if newly produced ions (e.g. ionized products from an exosphere around Dione) are added to the surrounding plasma flow. The inference of activity is based on the lack of direct evidence that a substantial exosphere exists around Dione, and from theoretical calculations suggesting/(confirming?) that surface sputtering from plasma cannot account for any considerable exosphere around that moon.

So practically, what was detected were hints of mass addition near the moon. The origin of this mass addition is still undetermined, but the favored scenario is that there is activity. On the other hand, we now know that around the period of the flyby, Dione was immersed in a new radiation belt (produced after a solar storm impacted Saturn) , the presence of which could have modified the sputtering rates and have produced a transient exosphere...

One flyby is never enough...

69 days, 4 hours, 53 minutes and 17 seconds until D2

Did I miss something?

In the 1/27 press release on the T66 flyby, it says that this will be the "22nd Titan encounter in Cassini's Solstice Mission."

I am sure that it is a slip of the pen, but it is almost certainly a good sign that john_s is right and the Solstice Mission is a go. Can't wait for the formal announcement, though.

And I really can't wait for those proximal orbits.

Isn't solstice what we're in now?

Phil

No, we are still in the Equinox mission until July 1.

I thought we were still in the Equinox Mission, at least until the middle of this year. As far as I know, XXM, otherwise known at the Solstice Mission, has not yet been formally approved. Maybe it will be in the budget that we will see tomorrow.

"No, we are still in the Equinox mission until July 1."

Oh yeah - well, I knew something was lining up.

Phil

Do you think we can construe 'continues operating 11 planetary missions' (from Van Kane's digest of today's budget proposals) as approval of the solstice mission?

Oh I think they'll approve it. The cheapest kind of mission is the one you don't have to launch. And how can they resist the grand finale?

--Greg

Now it's official and approved

http://saturn.jpl.nasa.gov/news/newsreleas...elease20100203/

w00t!!!

2017 baby

Finally!

The only sad part, you can now mark on your calenders, September 15, 2017:

Click to view attachment

If it manages to live that long and remains in good health, I don't think we'll really have reasons to be sad. More like grateful for what will have been a truly great mission.

When that time arrives I will give my paper model of Cassini the same send off I gave my paper model of Galileo on September 21, 2003.

Wow, I should do the same thing. I built my paper model (now squished, with a detached HGA and a missing Huygens) the weekend Cassini launched...

Mine has also seen some wear and tear over the years. I think it's in a shoebox somewhere at the moment. I tied a bit of cotton to Huygens to stop it from going missing.

Hey- I did that too!

John

Beware the ides of September....

Amazing! I remember wondering if I was going a bit mad when I did it. Glad to know I wasn't alone.

[quote name='volcanopele' date='Feb 3 2010, 12:34 PM' post='154945']
The only sad part, you can now mark on your calenders, September 15, 2017:

Oh, but think of all the sights we will see and all the cool things we will learn.

Oh, boy, oh boy, oh boy! I am so looking forward to this.

On to the proximal orbits!

Quite right, there are quite a few great things before that fateful day, and besides that's not for another 7 years! We get seven more years of Cassini awesomeness, not to mention Dawn, Juno, New Horizons, and MESSENGER before the end of Cassini.

To put it into perspective, Cassini's mission at Saturn up until now was shorter than that. And the prospect of having Cassini live to witness Rosetta and New Horizons prime science missions... Here's hoping for that!

Updated my realtime simulation with the good news! Cassini has now completed 61.8% of its mission by time and 68% by distance flown. Distance to fly to impact estimated to be 2.5 bn km w.r.t. Sun, 16.9AU. Does anybody have a SPICE kernel for the extended mission?

Also updated the full mission timeline ... it's one long page by now! I assumed that it is still XXM - SM7 that's being flown.

Go Cassini!

I use ftp://naif.jpl.nasa.gov/pub/naif/CASSINI/...09248_17265.bsp

This covers the period from mid-September 2009 until the end of the mission. You definitely want to switch to this as I am sure this will affect the timings of many of the non-targeted events.

Aaaah that's the one to use, thanks a lot. Must have missed the file end date. Will update the flying distances in a couple of hours.

I don't think it will change encounter times, I took those from http://www.mpi-hd.mpg.de/cassini/xxm/SM-7/SM-7_all.txt ... unfortunately I'm not blessed with trajectory analysis software etc that can nicely spit out encounters. I still live in the time of state vectors and Pythagoras ... and I am NOT going to calculate all those 1400+ events manually!

Yay! Bring on those seasonal variations!

Awesome, 7 years.

AWESOMNESS PLUS!!!!!!

Will Titan’s northern lakes start to evaporate? What methane storms accompany the seasonal changes? (Titan is my favorite… yes she is)!

No, WAIT... more Enceladus plume tasting!!!!! (Enceladus is my favorite.... yes she is)!

No, WAIT ... CLOSE IN passes between the rings and Saturn... (Saturn is my favorite .... yes she is)!

No WAIT... ring spokes evolution over time!!! (Rings.... favorite.... )!

No Wait ...

tail wagging furiously

Craig

Fantastic news, but bittersweet for some...

Posted without further comment as I know I'm close to off-limit discussion areas...
(Admins - I'll understand if you delete this post)

Oh no....I just read they are to plunge Cassini into Saturn in 2017 !

To co-incide with the exhaustion of spacecraft consumables after a 13 year study of the Saturnian system.

Nothing to be sad about - the phrase 'blaze of glory' has never been more apt.

People just have to realize orbiters doing orbital tours like this cannot last indefinitely. They use consumables that eventually have to run out and then the spacecraft orbit becomes uncontrollable. Barring hardware failures, it's still somewhat different than Mars rovers in that regard.

A generous lifespan - an immortal legacy - what more could anybody wish for?

Definitely! I'm excited about the news!

Another thing to keep in mind, MahFL, is contamination. Enceladus became a very attractive target for astrobiology since the arrival of Cassini. It would be a shame of biological contaminants were to be accidentally introduced onto Enceladus from Cassini though an impact in the distant future. Depositing the spacecraft into Saturn is like throwing away a used band-aid. Nothing you can do with it anymore, and you don't want to risk bio-contamination. This helped motivate the Galileo plunge into Jupiter, avoid contamination of Europa.

Can we expect any science from Cassini during the Saturn plunge?

Absolutely!!

Cassini might get to actually taste Saturn's atmosphere on it's way in. Check out this repost here.

Are there any close or non targeted flybys of Hyperion in the XXM?

RTFM ;-)

This link was posted in this thread earlier today:
http://www.mpi-hd.mpg.de/cassini/xxm/SM-7/SM-7_all.txt

Some questions about Cassini's final maneuvers.

John Spenser's description on Emily's blog states that a final Titan fly-by will perturb Cassini's orbit into a narrow cloud-scraping orbit inside the ring system. After 23 orbits, "a final distant nudge from Titan on September 11, 2017 delivers the death blow, altering the orbit just enough to drop Cassini into Saturn on September 15."

Is that final nudge a pure gravitational perturbation, or is it assisted by Cassini's propulsion system? How far away will Titan be when it delivers the fatal nudge?

TTT

That's a purely gravitational nudge from Titan- no propellant required. That final "close" approach to Titan will be at a range of 86,000 km.

John

I have used that file in my timeline, hence you can also search my website by target: http://www.dmuller.net/spaceflight/target....target=hyperion

Some more questions about Cassini's final plunge.

Is it expected that the vessel will be completely vaporized as it flames through the upper atmosphere, or are some pieces likely to survive to continue their descent at a stately terminal velocity?

If the latter, will the remnants continue to sink until they are vaporized in Saturn's hot core, or will they survive, highly compressed but still distinct objects, bobbing away in some cooler region of the atmosphere?

I've also wondered about the question Tom raises.

Fascinating to think that the Pu in Cassini's RTGs will be the heaviest constituent atoms of Saturn for the for the foreseeable future