Perhaps now would be a good time to start a new thread on the Extended-Extended Mission.
http://www.space.com/news/090127-cassini-mission-extension.html
One hopes the thruster swap doesn't affect any decision on long term planning - http://www.sciencedaily.com/releases/2009/02/090202161457.htm
Wait....what?
(from space.com article)
"such as evidence of what appear to be cryovolcanoes spewing extremely cold liquid into the atmosphere of Titan."
Did someone detect lower temperature spray actively venting????
VIMS may have detected photometric changes at Hotei Arcus and in a region of Western Xanadu.
http://gishbar.blogspot.com/2008/10/dps-meeting-so-far.html
Ahhh, OK, I get it:
The material when erupted would have been "extremely cold" by our standards, but probably warmer than the surface temp by Titan standards.
(So, an erupting plume of locally cooler material was NOT detected on Titan)
Sorry if I got a little pedantic, I wanted to confirm I hadn't missed something....
Of course, I didn't start this thread completely randomly:
http://saturn.jpl.nasa.gov/news/significantevents/significantevents20090205/
Does that mean that a tour has to be selected before the go-ahead is given for another extension? That seems the wrong way round to me.
BTW Do you know what the four candidates were? (Yes or no will do.)
Yes, I do know what the four candidates were. The one selected is pretty good and it seemed to please the most groups in Cassini (obviously, why else would it be selected). I preferred some of the Titan flybys in another tour, but since the tour selected won't exactly match the one that will be flown, who knows, maybe one the Nav guys and gals can adjust one of the Titan flybys to look like one of the ones from one of the tours not selected.
When I read about this last year
http://www.lpi.usra.edu/opag/march_08_meeting/presentations/spilker.pdf
I read that the prime mission had managed to get radar coverage of 22% of Titan's surface and that the XM would get an additional 8% -- for a total of 30% across 6 years. There was no mention of how much the 7-year XXM might get, but it would be nice to know. Is it reasonable to hope for an additional 20% coverage (for 50% total)?
--Greg
At this point we have JUST selected which tour we want to fly, and at this point, it is too early to start slicing it up until we know kind of funding we will be look at for the XXM.
Can you give us any highlights? Any Iapetus flybys?
Twelve more close Enceladus encounters???? Oh joy. More skeet shoots. More global mosaics. More 'sniffing' the plumes.
A lot of people, myself included, get a bit morose when we think about how long it will be before the next Saturn mission arrives. But I am heartened by something I heard once in a lecture at JPL.
Ellen Stofan was giving a talk on discoveries at Io by the Galileo mission. I think an audience member asked her if she had any regrets about the high gain antenna problem, and the data she had lost because of it. She told us of a conversation with a Voyager researcher, who had said that he did most of his research on Io based on about 20 key images from Voyager. She went on to say that she did wish they had some additional thermal map images, but she was pleased with the rest of the data set, and wasn't even sure if she would be able to handle much more.
I'm sure she was putting a bit of a positive spin on things, but it was an interesting point. Twenty of the right pictures are worth more than 200 images at random. By the end of Cassini's mission we will have had more than twenty close flybys of Enceladus, with a carefully selected set of gravity, fields, particles, and remote sensing data.
And that ain't chicken feed.
volcanopele, when publish the complete list of all flybys the Cassini's Extended-Extended Mission mission?
From the latest Cassini Significant Events report:
"A two-day NASA Senior Review of a proposal for a Cassini Extended Extended Mission (XXM) concluded today. The review board's comments and questions indicated that they were quite impressed with the science, science team, and technical presentations, and that they understood and appreciated the XXM plans, rationale, and concerns. Within a month the final review board report should be available and some time after that a final decision is expected from NASA Headquarters."
They were only quite impressed?
A 12 km Enceladus flyby sounds nice =) (When do we finally land? )
I, actually, find the rock moons rather interesting.
Has Mimas ever gotten close flyby?
No, no, I meant that there are 12 encounters of Enceladus with C/A distances of less than 10,000 km.
The Helene encounter is currently around 1800 km on June 18, 2011.
Looks like both flybys (the other being on March 3, 2010 at 1820 km) will allow for nearly global imaging of the small body so that after the two flybys, Helene should be pretty well mapped.
I found a website which lists 4 different scenarioes for the XXM at http://www.mpi-hd.mpg.de/dustgroup/cassini/xxm/xxm.html
Anybody has any idea as to which one is most likely to be chosen?
It was SM-7.
Just heard Carolyn Porco speak at Spacefest this afternoon. She saved Enceladus for last in her talk, and she spent more time talking about it than she did about Titan. In discussing the XXM, she was most excited about the additional Enceladus flybys, and also about the ring plane crossings.
Is there something that indicates what sort of Titan coverage we might get during the XXM?
--Greg
Cassini having a very bad day
Nothing unusual about that news release.
As previously discussed there are no targeted Hyperion flybys. However, there are some pretty close nontargeted flybys:
HYPERION 2010-332T03:31:35 Nov28 Sun Inbound 71598.9 km flyby, v = 4.9 km/s, phase = 73 deg
HYPERION 2011-237T17:50:51 Aug25 Thu Outbound 48781.7 km flyby, v = 5.2 km/s, phase = 106 deg
HYPERION 2011-259T13:22:45 Sep16 Fri Outbound 57347.5 km flyby, v = 4.8 km/s, phase = 84 deg
HYPERION 2012-068T01:21:42 Mar08 Thu Inbound 93452.2 km flyby, v = 5.5 km/s, phase = 148 deg
HYPERION 2015-151T13:42:21 May31 Sun Outbound 35456.9 km flyby, v = 4.3 km/s, phase = 71 deg
The last flyby in particular is at much closer range than any of the flybys so far with the exception of the targeted flyby.
In addition there are several flybys of Mimas at significantly closer range than the closest flyby (~61,000 km) of the primary mission. There are also many nontargeted flybys of Tethys including two flybys closer than 10,000 km. The W/NW part of Odysseus isn't particularly well imaged, hopefully this 'gap' gets filled.
There are many nice flybys of Rhea. There isn't very good stereo coverage near 0° longitude. Hopefully that relatively small 'gap' gets filled - I want a high resolution DEM of Rhea's *entire* surface .
Lots of nontargeted Dione flybys as well and many flybys of the small 'rocks'.
I'm a bit surprised there are no Voyager class (~100,000 km) Iapetus flybys since there was a ~120,000 km flyby early in the mssion and that one was by luck/accident and not planned. It happened when the first few months of Cassini's trajectory were altered in response to problems with the Cassini - Huygens communcations.
This is going to be a very interesting extension to the mission provided everything goes well.
Any estimates available on annual cost of the XXM? I recall reading that current mission costs are running about 80 million dollars. They had hoped to get that down to 40 million a year, but it was deemed impractical to go that low.
Following the 'proximal' link I've just read that piece by John Spencer. Made me wish I had a hat to throw in the air. I always said we needed a long lived 'weather satellite' for Titan in particular, now it seems that Casssini can take on that assignment and a lot more besides. Will it be funded? Well I don't think NASA will ever be offered so much science at so small a cost.
Clicked on the link Paxdan provided for the Planetary Society. Now that's a story!
Kudos to the Cassini team for their great planning and hard work. I appreciate the fact that they tried to work in another Iapetus encounter. It just wasn't in the cards.
Volcanopele's cryptic picture now makes perfect sense. So this is how the journey will end. Not with a whimper, I trust. Hope Cassini is transmitting right to the end.
I've just read John Spencer's "Solistice Mission" article on Emily's blog. It made me extend my lunch break as it was such a fantastic read!! Let's just hope that the team can make a proximal orbit around the money and get the required slingshot effect to take us to the pay off on September 15 2017!!!
I know most people who come here keep an eye on TPS too but it seems appropriate to link to the excellent new flybys diagram for Cassini's whole mission, existing and proposed:
http://www.planetary.org/blog/article/00001857/
It's breathtaking how much one spacecraft can undertake.
Great write-up!
In the (pretty) graphic representation of the mission Emily posted today on her blog it mentions G Arc flybys, one of them taking place next year. What are the observations like for these?
Anybody know when a decision is to be reached on this? There seems to be a lot of Cassini news today, and the tour highlights for all of 2010 appearing on the Cassini website did make me wonder if something could be happening.
We hope to know more after the President's 2011 NASA budget is released in early February. However it's very unlikely that the plug will be pulled with only a few month's notice, so it's a pretty good bet (but with no guarantees) that the current 2010 flight plan will be executed as currently planned.
John
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.
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...
Did I miss something?
In the 1/27 press release on the http://www.jpl.nasa.gov/news/news.cfm?release=2010-032&icid='NewsFeaturesHome' 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/newsreleases/newsrelease20100203/
w00t!!!
2017 baby
Finally!
The only sad part, you can now mark on your calenders, September 15, 2017:
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...
Beware the ides of September....
[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 http://www.dmuller.net/spaceflight/realtime.php?mission=cassini 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 http://www.dmuller.net/spaceflight/mission.php?mission=cassini&appear=black&mtype=scet&showimg=yes&dispwide=no ... 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/kernels/spk/091005AP_SCPSE_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.
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 http://www.bbc.co.uk/blogs/thereporters/jonathanamos/2010/02/cassini.shtml...
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?
Are there any close or non targeted flybys of Hyperion in the XXM?
Some questions about Cassini's final maneuvers.
John Spenser's http://www.planetary.org/blog/article/00002331/ 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
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
I know it makes scense to plunge into Saturn, my original comments were more a knee jerk reaction on hearing they were going for the plunge.
I think it's a sad thing to crash a spacecraft like Cassini into Saturn.
I remember that when Cassini was developed many options were mentioned, like orbiting Titan or swing te spacecraft out of the Saturn system in an orbit around the sun.
By making the most of what Cassini was designed to do ( orbit Saturn and observe it's system ) I assume they've traded any possible outside-of-the-box fates for Cassini for just more Saturn observations, assuming the XXM will use up the vast majority of remaining fuel.
Yes, sure, CAP-Team, but the science is inferior. Here we will get the mass of the rings, chemistry of the upper atmosphere of Saturn, the manetic field at very low altitudes, plus great ring/inner moon imaging opportunities. Escaping Saturn gives us nothing, and I think it was already found to be too difficult to get into Titan orbit, plus inferior science (a bit on Titan but nothing on the rest of the system.
Phil
"one of the driving considerations behind the end-of-mission scenarios is to avoid even the small
probability of hitting Europa "
That would need one heck of a gravity assist to hit Europa!
Phil
One thing to keep foremost in mind is that the PPPs & similar protocols are designed with full knowledge of the abundance of ignorance that we currently possess with regard to the tolerances/constraints required to not irrevocably screw up pristine extraterrestrial environments.
In that sense, they represent considerable foresight & forebearance. Minimizing changes to systems with complex (and not even close to being fully understood) interdependent attributes seems exceptionally wise.
I think the science we will get during the close Saturn passes will be magnificent. And those close passes I assume are risky. Not sure if CASSINI could be pulled out of that orbital configuration once she takes those dives.
Nothing lasts forever. I would rather a last grand dive into Saturn than a lonely and useless orbit of the Sun. Even if that were possible in the end.
Craig
Well...let's just say that it's a statistical certainty that incredulous claims will be made by those who lack credibility, and eagerly accepted by those who lack critical thinking skills.
(That reminds me: Time for my annual re-reading of Sagan's The Demon-Haunted World: Science As A Candle In The Dark. It's the only book I ever bought for each of my children.)
Onward, anyhow. The XXM promises to provide something hitherto unprecedented for the outer planets: long-term observation of seasonal effects on not just one but at least three active worlds! That is what they call bang for the buck.
Just noticed it's gonna be a "crashy" 2017 ... one month after Cassini enters Saturn's atmosphere (15 Sep 2017), it is Juno's time to disintegrate in Jupiter's atmosphere (16 Oct 2017)
Yeah, it's pretty awesome that Cassini will be in a Juno-like orbit at the same time Juno is in a Juno-like orbit; it will be fascinating to compare the behavior of the two giant planets' magnetic fields and plasma environments under identical solar conditions. Fascinating, that is, if you're a plasma physicist. Not my cup of tea. But I'm excited on their behalf
So assuming all the orbiting missions get extended, by then we could have 6 planetary bodies being orbited by spacecraft. Awesome!
The recent NASA-JPL webcast presentation about the Cassini mission's "Grand Finale" featured, among many other interesting things, a slide with a diagram of the 2017 "proximal orbits".
I thought that diagram was really interesting, so I saved a couple of screen grabs.
Does anyone here know if the diagram is available in hi-rez form somewhere?
Also, does the size of the blue dots represent navigation error probable size?
Thanks very much.
From the DPSEPSC conference;
Thursday press conference coming, with INMS team involved:
https://www.jpl.nasa.gov/news/news.php?feature=6809
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