http://www.nasa.gov/topics/solarsystem/fea...s/20090218.html

There will be some happy people, and some disappointed people. Both systems have plenty to offer, so no one should be too upset.

I'm not upset (or surprised). I always wanted both, and with luck we'll get both. There is no law that says there has to be a ten year gap between them. Returning to Saturn and Titan at a season complementary to Cassini's visit is a good argument for not waiting that long.

Now I'm wondering how this will play out on the European side. It always struck me as awkward that ESA should have a stake in the overall decision two years before it fully commits to participating. Also, supposing that Nasa did go ahead with both in (relatively) quick succession it's highly doubtful that ESA would be able to contribute to both.

Of course anything is possible if the will is there. I await an ESA statement with great interest.

For those, as I, who were looking forward for a TSSM selection here are some words that just arrived my e-mail from Athena Coustenis, TandEM project leader:

"It seems we may have to wait a little longer to see this mission launched, to plunge through Enceladus' plumes, to hover over dune fields and to land in a Titan lake. No matter. The first aim of this community is to have the need for a future space mission to the outer planets recognized and transformed into reality. We may be heading for Jupiter first, but as said in the text, and as it has been well demonstrated by the reactions within this community, the public and the press, we shall need to go even further in the future.

I take this opportunity to say that during the past 15 months I have had the immense pleasure and honor to work, exchange ideas and argue with you all over the most fascinating subject ever: a future mission to return to the Saturnian system and hunt down information on fascinating aspects like Titan's atmosphere and surface, Enceladus geysers and Saturn's magnetosphere. For some of us, the adventure had even started earlier, when we were preparing the proposal for Tandem within the framework of ESA's Cosmic Vision 2015-2025 or the study of the 2007 Flagship Titan Explorer mission.

I want to thank you and tell my appreciation, in particular to my friends and colleagues of the JSDT and the ESA and NASA study teams, who have managed to create a complete science and mission architecture case out of nothing within such a short time. They have done this with help from all of you. AND WE ARE READY TO GO ON."

Sometimes you win sometimes you lose, the important now is that we're going somewhere...Onward Europa Jupiter System Mission!

Although I was a "Titan Now" kind of person, my first reaction is more of excitement than disappointment. Two orbiters? Not too shabby. It will be great to see the Jupiter system get the complete Cassini treatment... times two!

Just curious. Does anyone think that there may be plume activity on Europa similar to that on Enceladus?

Plume activity on Europa can't be ruled out, though it's perhaps not very likely. Europan plumes would be much smaller than those on Enceladus (more like Prometheus-sized), due to the higher gravity, and might have been missed by Galileo, which of course had very limited ability to do extensive monitoring. And remember that on average, Europa's surface is much younger than that of Enceladus...

John.

It's much better than that - orbiters not flybys!

The beautifully variegated surface of Ganymede is the big history book of the Jovian system - much more informative that a lot of recently formed pack-ice.

Plumes on Europa? I doubt it but who knows.

Rui - nice one. You seem to be on everybody's mailing list! May we expect some follow-up interviews at spacEurope?

Sorry for the ignorant mode here but I don't know the mission architecture...does the future mission count "only" the two orbiters or are there plans tu include extra goodies, an impactor or something similar towards Europa?

EDITED: ngunn, that wasn't an exclusive e-mail...
Regarding spacEurope, I've made campaign for TandEM...don't tell me you didn't follow it?! I even had some graphics of mine and that beautiful logo (it was...it was...) included in the mission's pages...
Interviews are not predicted so soon I'm afraid...in March/April we'll talk about it...

Well, I was hoping for Titan, but Ganymede & Europa will be fine too!
It'll be great to finally have a torrent of data streaming down from the Jovian satellite system after the painful trickle that was Galileo's tour.

Plumes or not, it would be great to see some signs of activity since Galileo. There are certainly lots of cracks to look for changes in.

Rui - I always keep an eye on spacEurope - even when it's quiet. I have lots of questions now, such as: Will CNES proceed with development of a Titan montgolfiere? How soon could ESA scramble a TITAN LAKE EXPRESS outside of the flagship framework? In time to arrive before Cassini dies??? I'm counting on you to find out!

Oh yes, and will Ganymede beat the astronomy missions in 2011?

I'll give a shot but in the meanwhile I'll tell you something...TandEM was proposed under ESA's Cosmic Vision for the 2015-2025 window, the following, if I'm not wrong, will cover the 2025-2035 timespan...where will be Cassini by then?...will there be a will to pursue with the project in the following years or will it stay dormant until the following presentation of proposals?...Guess we'll have to wait and see...but I'll ask!

I originally preferred TSSM but eventually became fairly neutral so overall I'm happy. Actually I kinda expected this result - comparing the kind of coverage Cassini has given at Saturn to what Galileo did at Jupiter is one obvious justification. Lots of atmospheric movies of Saturn at several wavelengths compared to very limited movies of Jupiter (actually the best ones are from Cassini), extensive ~1 km/pixel multispectral imaging of Saturn's satellites compared to Galileo's limited color coverage, to name a few. And significantly better instruments on Cassini. Also the Cassini mission isn't over yet while the Galileo mission ended several years ago.

EJSM is going to be a spectacular mission, a 'Galileo 2 on steroids' - and with a functional HGA. The only problem is that ESA hasn't commited to flying the Ganymede orbiter yet.

Am I the only one here who preferred EJSM? TSSM is surely a great mission concept too, it was just my 2nd choice

I also preffered TSSM, based mostly on the idea that Jupiter could be explored with more limited missions (such as the Io Volcanic Observer) but that Saturn/Titan really needed something more in the flagship range. I also thought that the TSSM was mature enough of a mission canidate to compete with the EJSM .

But, it seems that the reviewers felt that the Saturn elements needed more technical study. That changes my mind. If there is a technical readiness difference, definately go with the Jupiter mission.

I hope that the Europeans actually do the Ganymede mission, but in any case we now know that the Europa mission is a go.

One last thing: at least the cruise time to Jupiter is much shorter than the Saturn system. We'll be seeing great pictures by 2026, instead of having to wait until 2030. As an aging baby-boomer, I'm all in favor of that.

mps, don't worry, you are not the only one As I have done so much work on Titan and that is my second favorite celestial body, I would have been fine with TSSM. But the Jupiter system really needed the kind of treatment Cassini has given Saturn, and more. EJSM does that. And of course it studies Europa and Ganymede quite extensively too.

Well this is indeed a fascinating news, like long way to go but still something to look forward to. For last 10 years, just following the Cassini mission has been nothing short of a blessing, and hopefully getting an opportunity to live for another Outer planet Flagship mission is just too captivating.
EJSM or TSSM , both are amazing missions and will keep all of us busy to cherish this fascinating world of planetary exploration ! Good luck to NASA & ESA

That would be the European in situ elements presumably. The irony is that ESA could hardly have passed up an opportunity to do those really exciting things, whereas there must now be a finite risk of no European contribution at all. I do hope I'm wrong.

If there is going to be continuing close cooperation between NASA and ESA on big projects it would be nice if they could synchronise their decision schedules.

Go Ganymede!

Great great news! I was also at first a bit pro-titan but now i feel fine with this decision, actually quite positive, because both missions have been recognized important ones and are moving forward. As mentioned here before I also believe "Cassini's goodness" was one reason why Jupiter is now getting its shot. And to be honest, we really need a Europa orbiter, finally. Science moves on small steps and this way we will eventually have Europa lander/driller/diver sooner in the still distant future. This also levels nicely the scientific returns on two giants, Jupiter after all is still the most important planet in our system in many aspects.

One thing here is also, that if Titan mission would have been given priority, pretty likely there would have been then more of these less capable discovery-class stuff going to Jupiter anyway, so this would have been effectively eliminating other interesting discovery options like Venus balloon/lander. Titan anyway needs to be flagship-way and letting technology mature a bit especially with balloons we improve chances of success there in the future.

What a great time to be anyway. I am just impatiently waiting for first pictures from Ceres, Pluto/Charon, around Mercury and of course the first light of Kepler...

Selection of the Jupiter mission would mean that the late-10s Jupiter-Saturn slingshot opportunity will probably be lost. The next will be more than one decade later. too bad!

Jupiter gravity assists fizzled out in 2015, just too early to be considered in the baseline in the 2007
Titan Flagship study (although it was considered as a possible alternate launch for an accelerated program -
see section 6 of the public release report for launch date options)

IIRC these opportunities recur after 15 or 17 years or so, so a late 2020/early 2030s launch may be
favorable for a Titan flagship as the 'second' outer solar system flagship. Won't be during my
professional lifetime, though.

2026 arrival?

Better hurry up and wait.

Ralph, I figure the JS assist opportunities out to recur every 20 years, because 1/(1/12 - 1/29.5) = 20.2. That doesn't say how long the launch window stays open, though, but is it as much as three years?

--Greg

That was my assumption when I read the announcement. The Titan elements would need to be physically integrated with the US orbiter, and there would be relay duties. Neither of those technical requirements exist on the EJSM. The Laplace studies go back several years and the ESA studies of the TSSM started fairly recently. All of that would suggest that the Titan elements are the most immature of all of the components.

The NASA timetable could leave the inviting air of Titan balloon-free for about 30 years. That's a big window of opportunity for someone else to pull off the historic feat, even if it carries less scientific clout than a full-blown NASA flagship. I bet they ring you first!

In my perfect world, the Jupiter flagship is earmarked and slated for launch first, but money and effort is also poured into the technological development of the TSSM mission. Such that the TSSM launches within months after the Jupiter flagship.

'Course in that same perfect world, my investments have gone through the roof and I've already retired and am sitting on a beach with a fuzzy drink...

Jim Green posted a message on the OPF website: http://opfm.jpl.nasa.gov/community/decisio...lagshipmission/
I just put up a post on my blog about the next steps for EJSM: http://gishbar.blogspot.com/2009/02/whats-...ter-system.html

I really anticipated that EJSM/JGO would be the choice. Poor GALILEO could only send a dribble of data homeward. It is time to go back to Jupiter system with a mission that can recoup what was not possible with GALILEO due to it's stuck high gain antenna. It is the Europa / Jupiter research communities turn.

Who can guess what new wonders EJSM/JGO will reveal?

Titan's dunes and lakes and strange highlands will get their turn. As will the plumes of Enceladus.

The 2020's is some time ahead.... we can hope that newer technologies will mature enough to fling smaller, more capable tech at the worlds out there so far from the Sun..... (just hope here - since I want the ice giant research community to get it's turn at Uranus/Neptune as well....

So much to discover and these little mayfly lives we lead are so short. But I really cannot complain. We know SO much more than when I was born.... watching the universe unveil continues to be a source of solace in a human world that sometimes seems all too crazy.

Craig

I preferred EJSM (although I also sort of wished they could have picked both so we didn't have to wait until 2030+--or 2040+ more likely--before NASA returns to Titan :-( ). By 2026 NASA will be way overdue for getting back to Europa.

As Jason Perry's page points out , though, and others here have alluded to, though "JEO is safe", "despite this downselection, the contest isn't over for JGO" back at the ESA. So let's not bring out the champagne and dancing girls just yet. Save those for when JGO gets the final go-ahead.

======
Stephen

Since the probe that will be flying by Io has been approved, can I have champagne and dancing girls anyway?

It sure seems to me that ESA has made up its mind.

http://www.esa.int/esaCP/SEMPHGWX3RF_index_0.html

Although we should be very happy about returning to Jupiter, we shouldn't be complacent on JEO. With a 2020 launch a lot can happen. I think we all need to get strongly and vocally behind JEO, or else we may loose yet another outer planet mission.

We had an outer planet flagship launch in the 70s, 80, and 90s... and none in the 00s, and we'll have none in the 10s. Now they're making us wait until the 20s for one. I don't think we'd be out of line to demand that they send two in the 20s. Especially given the extremely high degree of commonality in the designs.... heck, most of engineering team was shared between both studies.... why can't engineering teams be shared in phase A/B too?

EJSM and TSSM both return a huge science bang for the buck... I doubt NASA has many other options for such a large return on investment. Especially if looking for life is a focus, nothing else is even in the same league. These two missions should be a top priority for NASA.

Let's do a MER to the outer solar system! Spirit and Opportunity on performance enhancing drugs. :-)

How did it happen that there was such a gap between Cassini and this mission? Was this is a result of the Battlestar Galactica JIMO fiasco?

Assuming that the current levels of funding (adjusted for inflation which hasn't happened in recent years) continues, there is probably money for one flagship mission in the 2020s. In the 1990s, we had Cassini, in the 2000s, we have the development of MSL, in the 2010s JEO. A Titan Flagship return would be in competition with a Mars Flagship mission (either another big rover or deep drill or sample return) and a Venus Flagship mission (which will be proposed in the next month for the 2020s).

I think that if you really want a Titan return to fly in the 2020s, the best bet is to figure out how to do one for a bit over $1B. The billion dollar box studies said it couldn't be done for less than $1.5B-2B. If that is true, then there is a harsh competition between excellent Flagship missions for the 2020s. If someone could figure out how to return to Titan for half the price of a Flagship, I see some hope.

Was MSL explicitly funded instead of an outer planets mission or did it just kinda work out that way in the end?

Caveat: I'm trying to avoid a political discussion. Just answering his question with history as I remember it.

I don't think the term 'flagship' came into common use until around the time of the Decadal Survey in 2003. The survey concentrated mostly on non-Mars missions, so if I recall correctly in the Survey the term was used mostly to refer to the large outer planets missions like Galileo and Cassini. I never recall MSL reffered to as a flagship until around 2007-2008 when Michael Griffin called it one.

The reccomendation was that in every decade NASA try to fly one flagship, a New Frontiers mission every 3 years, and a Discovery mission every 18 months. (notice the nice multiples of 3 here..... 1 Flagship, 3 New Frontiers, 6 Discovery) .

The survey also recommended that if the missions could not be flown that often, that the ratio remain somewhat the same. In other words, do not attempt to fly 3 New Frontiers and 6 Discoveries in a decade, and then just keep putting off the Flagship. I read this as a deliberate attempt to get away from nearly a decade of all new mission starts essentially being Discovery class.

More or less NASA seems to be attempting to follow this recommendation. Over the last few years the rate of New Frontiers Announcements of Opportunity comes along every 5-6 years, Discovery every 3 years or so. Six years after the Decadal Survey we now have (hopefully) a commitment to an outer planets flagship.

Cassini - 1997, MSL - 2009 (goal), and EJSM - 2020, roughly speaking we are getting a flagship every decade or so.

Again, this is just the events as I recall them. Not trying to start a funding debate.

You're right. I guess how wide the flyby window (depending on the number of revs and Venus/Earth
encounters, launch could be any time) depends on the flight speed range, but I bet it is close to 3 years
(e.g. Cassini had windows in 1995, 1996 and 1997).

So 2031/2032 might be the earliest useful timeframe, but someone actually needs to figure out a real
trajectory. On the other hand, in that rosy future, maybe we wont need flybys because we'll have
better propulsion, aerocapture etc.... (and Titan Explorer 2007 and TSSM managed without flybys anyway)

Something that I can't figure out is how large the solar panels would be for the ESA JGO. JGO is much heavier on the imaging and spectroscopy than say Juno, and no one has tried to perform a "flagship" class mission this far from the Sun. (Sure there is Rosetta, but its primary mission sweeps back toward the Sun after the comet rendez-vous.) Can ESA pull off a large solar powered mission so far from the sun without having prohibitively large (and heavy) solar panels?

The last Decadal Survey (2003) called for two missions in the >$2-3B range, a Mars Sample Return and a Europa orbiter. The straight forward proposal for an Europa orbiter was changed to a very ambitious (some have used less charitable terms that aren't suitable for a family board like this one) proposal for a nuclear reactor powered multi-moon Jovian orbiter called JIMO (http://www.nationmaster.com/encyclopedia/Jupiter-Icy-Moons-Orbiter) by the then NASA administrator. After JIMO's cancellation with a new NASA administrator, there was no funding to restart a straightforward Europa orbiter.

The Mars Sample Return was effectively replaced with the Mars Science Laboratory as the big Mars mission.

There is no formal rule that I know of that there will be just one of these big missions per decade (the Decadal Survey called for two in this past decade), but that is how the funding has actually worked out since NASA restarted its planetary program in the mid-1980s. (There was a time when the only NASA planetary mission flying was Voyager with the repeatedly delayed Galileo mission as the only one in development. Those were the bad years.)

I think the term was coined during the early Goldin era unless it predates it. I remember him referring to Cassini as such.

You mean when Goldin wasn't calling Cassini "Battlestar Galactica" ?

As I recall he hated that mission, thought it was much too large and unwieldy.

At the risk of offending Titan-lovers here, I have to be honest and say that I'm glad Jupiter got the nod for this flagship mission, Don’t get me wrong; I love the Saturn system, and I love Titan too. What’s not to love about a planet-sized satellite that has its own atmosphere, coastlines, lakes and maybe ice volcanoes, too? And the proposed Titan mission sounds thrilling - who wouldn’t be thrilled to the point of blacking-out by the prospect of seeing pictures from a probe that has just splash-landed in one of Titan’s methane lakes, or from a balloon that is drifting over Titan’s plains - but that sounds like a very, very tough challenge to me. It will happen one day, I’m sure, but maybe not for another three decades… and I can’t wait that long! Jeez, I'm going to be 61 - sixty frakking one! - when the new Europa images start coming back. That's quite a depressing thought.

But I'm still excited at the prospect of seeing Europa again. It's one of my favourite worlds in the solar system. It’s captivated and fascinated me ever since I saw those first fuzzy Voyager images of it back in the days of Charlie’s Angels. (Oops, showing my age now!) and, spookily, I just finished reading John Varley's "Rolling Thunder" novel, a huge chunk of which is set on Europa. Reading it reminded me why I love its icebergs and ice cliffs; grooves and channels; crevices and crevasses. Voyager and Galileo showed us features on its mottled, fractured, colour-spattered surface that still make me shake my head in wonder. And those images, which are pretty good, were taken with old technology, cameras nowhere near as good as the kit we have today! Just imagine the stunning images we’ll see when EJSM starts taking pictures… we’ll zoom in on those jagged edged icebergs… see right into the fractures and pits and grooves… catch sunlight glinting off the vast ice plains… see Jupiter looming over Europa’s horizon, just as it’s been shown in space art for all these years…

Of course, these pictures are all a long, long way ahead, and I can't help wondering what kind of world we’ll all be living in then. As I said, I’ll be 61 in 2026... how badly will Earth and mankind have been affected by global warming and economic hardship by then? Will China already have beaten the US to the Moon, and be in the process of training astronauts for a manned expedition to Mars? Will we have the first picture of an Earth-like extrasolar planet? Will we have detected a signal from another civilisation from deep space? It could literally be a New World by then, in so many ways. I don't know whether to be excited or frightened by that thought.

But it's good to know we're planning the Next Great Mission.

And too easy to forget when we want more more more... although missions to Venus might belie that exact scenario.

Well said Stu! I had the same thrill from Voyager and Galileo. And on top of that there is Ganymede and Callisto... forgive me folks, but there is something very intriguing to me about the sublimating seltzer surface of Callisto, and the tectonics on Ganymede...... and how the freak does Callisto have an ocean when it formed too cold to differentiate.?

We stand to learn do much...

Craig ... 72 in 2025

"sublimating seltzer surface of Callisto"

Gold star for effective alliteration, sir!

Stu

Coming from our resident poet, I am quite flattered...

Thanks really

Who does not find these Callisto 'knobs' begging for better resolution..... sublimating seltzer.
http://photojournal.jpl.nasa.gov/jpeg/PIA03455.jpg

Of course, it will take the ESA contribution... JGO, to open up this world.

Craig

Artist's impression Callisto's Spires...

http://www.arcadiastreet.com/cgvistas/jupiter_130.htm

I agree. With four planet-sized moons, the surface area to explore is tremendous, and Galileo, while it was a noble salvage mission, barely could scratch the surface. I strongly favored this mission, although much of my bias comes from the fact that the Titan mission strikes me as more technically difficult (in the sense that it depends on more new technology), and is therefore more likely to be delayed.

WOW... very nice.

Thanks Stu!!!

It just makes me wonder what else we have missed on all the Galilean moons because of the spacecraft Galileo's
stuck high gain antenna... I am sure there are wonders galore awaiting us. And the boring places will not seem so boring anymore...

Then add the places we KNOW are not boring, Io and Europa...

Whew.... what a wonderful way to spend my 70's...

Craig