From Emily's LPSC blog: "Bob Pappalardo would not sit down until he got Cleave to acknowledge that Europa is the consensus highest priority of the planetary science community."

Cleave was obviously poorly prepared for this session, but I don't see that this acknowledgement is either meaningful or particularly accurate. If Europa were the "highest priority" of the PS community as a whole, then one might wonder why we were spending all this money on Mars. I could easily imagine that Europa is the highest priority of the outer planets community, but frankly I was surprised when Europa Orbiter appeared in the '07 budget (presumably the result of some serious lobbying on someone's part.) It was pretty obvious to me then that there would be no money for it, especially in the aftermath of JPL running the old EO project into the ground with cost overruns and engineering upscopes. (And JIMO is best forgotten.)

Don't get me wrong, I would love to be involved with a Europa mission (we did what I think was a good proposal design for EO) but I don't see either the money or the political support being there in the near term. I know it's frustrating, but one has to be realistic, and it might help to avoid the aura of entitlement that I perceive is building in some parts of the community (not referring to you, Bob). Of course, I am just a lowly engineer.

That was slightly sloppy reporting on my part, and I need to go back to my [illegal] recording to try to see exactly what Bob said. It generally appears that Mars is considered wholly separately from exploring the rest of the solar system (I am kind of curious how the financial priorities are set between the Mars program and everything else; I don't know anything at all about that).

Leaving out Mars, the Decadal Survey identified priorities for missions to other targets in the solar system, identifying one large class mission (assumed rate one per decade) and five medium class missions (assumed rate three per decade, with two extras listed) as being the top priorities of the science community. Europa stands alone in that large mission class. The five medium missions are, in order: Pluto/KB Explorer; lunar South Pole/Aitken Basin sample return; Jupiter Polar Orbiter with Probes; Venus In-Situ Explorer; and Comet Surface Sample Return.

One reason Bob wanted to stand up and say that yesterday is because he (and the rest of the Europa community) were alarmed by the possibility that Jonathan Lunine's provocative suggestions of Titan as being the one target he would explore if forced to choose one would be seen as "mixed messages" coming out of the outer planets community. Lunine's point is debatable, but as far as mission planning is concerned it's not really a relevant one. Planning out future missions requires not only looking at what questions scientists desire to answer but also the maturity of the field and the technological readiness to start a new mission. With Cassini still at Saturn it's not time yet to start a Titan mission now -- one would guess it would be a top candidate for the single large mission of the next decade, after Europa.

Doesn't look like NASA's too interested in considering large missions at all right now though.

--Emily

If you're in your 20's - you have Cassini
If you're in your 30's - you had Galileo
If you're in your 40's - you had Voyager
If you're in your 50's - you had Viking

yes yes - lots of overlap and doesnt really sit in those catagories properly, it's a metaphor more than a real survey of the past - but there's nothing for our teenagers - where is their Voyager? Has there been a point in the last 40 years when the next really big mission wasnt at least in the planning stages?

Doug

Frankly, it appears, at least to me, that Cleave may be poorly prepared for her job (AA/SMD). I don't mean this as an attack on her credentials, whatever those happen to be, but in light of the past few weeks, she seems to be increasingly isolated. First, Griffin holds in abeyance the Dawn cancellation pending "review," which seems to be a slap in Cleave's face, though this could just be a maneuver to buy some bureaucratic time. And now Cleave walks into the buzzsaw at "NASA Night." Given the reports of what transpired at the latter, I think Cleave would have confessed to the JFK assassination just to get off the podium

As for the substance of your post...


As Emily alluded to in her post, what is "highest priority" even among the subset of outer planets specialists is becoming uncertain. And in addition to Titan as a rival target, I'm waiting for an Enceladus Underground to start coalescing.

On its way to Pluto at the moment.

But what if "the maturity of the field and the technological readiness," not to mention the funding, is not in the cards for the strawman Europa mission recommended by the Decadal Survey as the next Flagship-class mission? Do we have to wait to punch the ticket of these prioritized mission sets when, for example, other new targets may emerge during the interim? The problem with Decadal Surveys (or all long-term "roadmaps") is that they're usually not too discovery-driven. Of course, the hurdles (programmatic and technological) facing outer planetary exploration are much different than those facing Mars exploration, but I wonder whether a prioritization scheme similar to the Pathways/Next Decade approach used for Mars might be useful for the outer planets.


True, which may make all of this debate moot.

I love NH - it's a wonderfull mission - but it's not a Flagship - it's shouldnt be left to be the biggest mission of the next decade and a half.

I'm surprized that Ceres is not considered a high-priority medium class mission; seems like it should rank higher than lunar sample returns. Considering it's a carbonaceous chondrite class 'roid with potentially some past planetary evolution, it seems like a survey (and sample return?) from it could be far more interersting.

Or is Ceres still considered a "small" mission class? I thought Dawn kinda proved it should be funded as a medium class mission.

"aura of entitlement" is forming? This is 'merica! Aren't we entitled to everything, all the time, and neatly packaged in excessive + disposable packaging? I'd like the new & improved Europa Orbiter to go please, with a side of stardust-style-impactors and a large, orange drink! Yeah - and "biggie size" it!!

Not only did the 2002 Decadal Survey rank Europa as the highest-priority target for a large non-Mars planetary mission, but OPAG has just officially ranked it above Titan ( http://www.lpi.usra.edu/opag/oct_05_meetin...ting_report.pdf '. pg 2. OPAG officially ranks Titan second, above Neptune.) Lunine, in short, was engaged in trouble-making, and Pappalardo was entirely justified in doing what he did. (Mars is in an entirely separate category all by itself -- it's NASA's official Holy of Holies, never to be questioned on any ground.)

The question at this point is whether a combined Titan-Enceladus mission is possible, and whether this really might upend the current order.

This is basically what Mike said (viz., "If Europa were the 'highest priority' of the PS community as a whole, then one might wonder why we were spending all this money on Mars. I could easily imagine that Europa is the highest priority of the outer planets community...").

The strange thing is that Lunine didn't seem to think he was trouble-making, and just as Cleave doesn't understand why the scientists are angry, Lunine doesn't understand why the outer planets folks are feeling threatened by his public suggestion (though the Leonard David article should answer that).

People here seem to be pretty dismissive of the possibility of a combined Titan-Enceladus mission but of course no one is actually presenting either a suggestion for or rebuttal of such a possibility at any of the sessions.

What most of the outer planets folks are saying about Titan is that the surface should not be explored until it is well mapped from orbit. They are asking themselves whether a New Frontiers mission couldl be sent to Titan with only two instruments: a radar mapper capable of 100-meter resolution and a 2-micron imager. These are all geologists talking though, and I think that the mission would be more interesting to more people with a third instrument that could do a thorough map of the atmosphere, such as a limb sounder, to map hazes, clouds, etc. (I'm a new fan of limb sounders now that we're doing public outreach on the Mars Climate Sounder.) But of course I don't have a clue how much mass/complexity that would add to the simple orbiter that the outer planets folks are talking about.

--Emily

So let me get this straight: the "outer planets folks" are pondering a New Frontier-class mission that wasn't even recommended in the Decadal Survey (i.e., the Titan concept you note above) while a subset of them are invoking the same Decadal Survey that lists Europa as the highest priority non-Mars Flagship-class target?

Sad to see all this intramural political wrangling interfering with the serious task of saving NASA's planetary exploration program. This very public lack of unity on the part of the planetary science community will only serve to justify the cuts in the minds of senior NASA and Bush administration leaders.

It's time to draft a consolidated, universally-supported agenda and start hammering it home to the bean-counters!!! I frankly don't care whether Europa, Titan, or Enceladus is chosen as the prime focus; the fact is that all of these bodies are worthy of Flagship-class missions, and the main goal should be to get such a mission funded. This petty bickering is undermining UMSF.

I'm profoundly disturbed by the notion that the prioritization should be irrespective of means, as Emily has lightly touched upon, or readiness, as Alex has touched on.

If a cheapo mission that scored major Enceladus goals came to light, then it would seem in at least one sense to become a more sensible mission than a blockbuster to Europa or Titan. But we also have to strategize -- all three of these satellites are going to draw us into twenty questions games, and the best first mission to one of them is not necessarily the mission that returns the most gigabytes of science data from that one. Europa and Enceladus offer possible free-return (or very cheap return) missions. Enceladus and Titan offer the possibility (not that I can sketch one out) of a single mission that delivers some science from the other one. Of course, Europa is in proximity to other worlds of interest, also. Europa also happens to be closer to Earth for potentially shorter cruise, but is cursed with its position deep inside Jupiter's gravity well; maybe a Titan mission *could* get to Titan faster than a Europa mission could get to Europa. Meanwhile, most Europa mission designs would be sharply time-limited, while a Titan mission might have a MERlike longevity. All of which is to say that I don't see any sense in prioritizing exploration while isolating science interest as the only factor. I'd much rather see a helluva mission to any of these worlds before an incremental follow-on to any of the others.

Sure. Such a mission would never get done this decade, so it's not incompatible with their citing the decadal survey. (No follow-on mission to Titan should really even be started until Cassini is done anyway, unless it lasts more than double its design lifetime.) Their argument is that this kind of mission should at least be talked about before they talk about landing on Titan (also not mentioned in the decadal survey), which is what Lunine was arguing for.

--Emily

Well, one should note that the "Europa Geophysical Explorer" mission recommended in the Decadal Survey wouldn't have flown in this decade, either. Neither would have JIMO.

True. I guess I meant "started," but the point is well made that the 2010s will be a decade without a flagship mission.

--Emily

No argument there, though I continue to believe that international cooperation (despite the digs about NASA being an unreliable partner) is the enabler for Flagship-class missions.

As for the Decadal Survey, I wasn't trying to be argumentative (Who? Me? ). It's just that I think the "community" should be careful in their recommendations. After all, the whole point of the survey was to present a united, consolidated view of what planetary scientists are recommending.

First, as I said, Mars is in a category all by itself -- the NASA brass recognize it as a gold mine for them funding-wise, and so missions for it are considered super-high priority by NASA regardless of what the actual planetary-science community thinks. (Jeff Bell tells me that Mars scientists, who benefit from this, are bitterly known by other planetary scientists as the "Mars Mafia".)

Second, I found out at the Europa Focus Group meeting who got Europa Orbiter into the 07 budget. As is so often the case, this was due to idiosyncratic personal enthusiasm by one Congressman --- John Culbertson of Texas, who showed up at the meeting to excoriate the removal of EO again and to swear undying enmity against any further attempts to delay it. He is an otherwise standard-model right-wing Republican who happens to be an amateur astronomer and geologist, with the result that he is apoplectic about the cuts in space science but isn't (yet) willing to buck the President by trying to pull money out of Shuttle/Station. (He said that he personally takes a dim view of it , but that NASA is stubborn in refusing to cut its funding.) As a result, he proposes to refund space science by increasing NASA's funding as a whole -- which I imagine ain't gonna fly, but we'll see.

Anyway, he not only got EO into the initial '07 budget, but was responsible for restoring $10 million of the cut funding for SIM. He also said that he was largely responsible for the funding for Prometheus, and that when he got it funded he had Europa in mind as a goal for it. (I hope someone gets a chance to tell him about the unwisdom of using NEP to study Europa, or he may unintentionally veer us off onto an unwise detour.) So there is at least one genuine, honest-to-God Europa enthusiast in Congress -- which is more than a lot of space scientists have.

Yeah, and they realize that. There is a lunch meeting tomorrow (Thursday) of people interested in the future of outer planets exploration, and I'll be very interested to see who shows up and what they have to say to each other. Also, the next OPAG meeting is in early May in Pasadena. I expect there will be formal discussion of this Titan question then, if not before.

--Emily

Regarding Titan exploration: the PS community currently harbors some hope that a Titan surface-analysis aerobot WITHOUT an accompanying orbiter might be flyable within the New Frontiers budget (e.g., the windblown-balloon version of Titan Organics Explorer). I'll believe it when I see it, though.

Meanwhile, Ralph Lorenz's study group has just concluded that a Titan orbiter with some small additional package (a stationary lander or a fixed-buoyancy balloon) might instead be the best next step. See the last page of http://www.lpi.usra.edu/opag/oct_05_meetin...an_work_grp.pdf . See also pg. 16-30 of http://www.lpi.usra.edu/opag/jun_05_meetin...s/opagtitan.pdf , and the orbiter part of the proposal in http://www.lpi.usra.edu/opag/oct_05_meetin...ngley_titan.pdf .

Such a relatively small stationary lander might very much be worth adding if Cassini can find a location on Titan that is likely to be the result of water cryovolcanism, so that the lander could look for complex water-formed organics. (Or maybe even the remnants of Titanian microbes vomited up from its subsurface water-ocean -- yes, they are thinking about just that in connection with Titan Organics Explorer, and thus one thing it's supposed to do is check any organics it finds for chirality.) That is, the lander would carry the relatively stripped-down science payload planned for TOE, plus maybe a seismometer. (I still think the Huygens team missed a major opportunity by not replacing most of those silly British surface instruments with a short heated core tube hooked up to the GCMS.)

As for a small nonlanding balloon: it might be worth doing too, and not just for weather studies. Titan is one world where cameras on a balloon could do surface observations which CANNOT be done by a camera from orbit, no matter how high-powered -- and Titan's surface is clearly so complex that something of the sort will be needed to understand the place. I also wonder whether such a balloon might carry a subsurface radar sounder -- which is starting to look like something else we will badly need to understand Titan, and which (according to Lorenz) is hard to put on an orbiter because of the difficulty in getting an orbiter down to a low enough altitude for it to work right.

That same extraordinary atmospheric scale height on Titan, though, is indirectly the cause of the one reason why it might be worthwhile flying to Titan before Europa: namely, that (as John Rehling points out) it's a hell of a lot easier place to either land on or orbit. Saturn lacks Jupiter's savage radiation environment; and Titan happens to be the easiest world in the Solar System at which to aerocapture an orbiter -- which would vastly reduce the craft's weight, and which (we were told at the November COMPLEX meeting) we will be completely ready to do for any world in the Solar System once the New Millennium program runs the one proposed Earth-orbital test of the procedure. In short, it may, repeat MAY, be possible to fly a Titan mission which would be fairly close in scientific productivity to Europa Orbiter, but much cheaper -- at which point it WOULD become competitive with EO.

The overall lesson, though, is that it is still way too early to even begin to decide what kind of mission to fly at Titan until Cassini has finished giving the place a far more thorough once-over -- which will take years. And that, in turn, might be a valid reason to delay Europa Orbiter -- if Cassini's later studies of Titan do indicate that it can be explored in a highly scientifically productive way for much lower cost than Europa Orbiter, with or without study of Enceladus thrown in as an addition.

But isn't that going to be a looming problem if NASA keeps on postponing a Europa mission?

If NASA waits around long enough it may well be the next decade before a Europa orbiter gets back onto its budgetary agenda. It is, after all, already 2006. Without an infusion of extra funds NASA's budgetary situation seems unlikely to change before 2010 at the earliest when the shuttles retire, and maybe not even then if the VSE swallows the lion's share of the newly freed-up money. If the Europa cheer squad are still waiting around for NASA's OK when Cassini ends they are going to find themselves competing for NASA's attention and money with the Titan cheer squad who will doubtless by then have plans for a followup mission or missions of their own. If NASA cannot afford missions to both places at the same time, then it will be forced to choose between one or the other. If that happens somebody is going to have to wait.

One might expect that to be the Titan folks. The problem for the Europa cheer squad, though, is that they are really after not one but at least two missions: a Europa orbiter followed by a Europa lander-cum-borer-cum-diver. Since much of the point of the first is to decide where (or even whether) to send the second that is going to make the orbiter seem merely an (expensive) precursor to the more sexy main event. Given much of the rationale for going to either place is to find life or its precursors, a mission to Titan may well look like getting the answers (or some of them at any rate) everybody wants sooner, more easily, and in a less expensive fashion than going to Europa.

======
Stephen

I suspect that it may be time for looking at much more creative options for Europa missions. The Europeans have studied an all solar-powered, two spacecraft mission. One report from several years ago on a possible NASA Europa orbiter stated that a fall back mission would be an intense set of flybys of Europa that could conduct radar soundings at each flyby (with the limitation that the latitudinal coverage would be primarily near the equator). Perhaps something like this could be combined with an internationally contributed lander/penetrator.

Well, I'm in my 30s and what I mainly remember is the long, long gap with NOTHING in the 1980s.

There were actually quite a few planetary missions in the 1980s,
especially if you count non-USA countries, but yes, no new planetary
missions by the USA were launched between the Pioneer Venus
probes in 1978 and Galileo in 1989.

And let's not forget Reagan's financial guy who tried to shut down
Voyager 2 in 1981 after its Saturn mission to save a few bucks.

...which is exactly why The Planetary Society was formed in 1980. Things are looking awfully familiar to people who have been around since we got started.

--Emily

That's pretty depressing, especially if you want to find a job in planetary sciences :*-(

Not to be pedantic but Magellan launched five months before Galileo. It's true, though, that the latter was started first.

If you're in your 60's - you had Apollo.

Well, there has been continuity....in outer solar system exploration, the pioneers started, and the Voyagers overlapped the end of their solar system mission. Then Galileo was launched just after Voyager 2 flew by Neptune, and Cassini had flown by Jupiter and was on its way to Saturn by the end of its mission. Now we have New Horizons with Juno on the way. What disturbs me is, ignoring the technological advances that skew the comparison, Juno and New Horizons seem more on the scale of Pioneer. Now, if we look at solar system exploration in general, MSL might fill the roll of a big mission.


I think it is really a mixed bag. There certainly is the lack of big missions coming down the pipe. But we are in much better shape than the 1980s, which, had Voyager and PVO not outlived their waranties, would have been limited to ICE, a "comandeered" planetary mission, the Halley flotilla, some Veneras, and Phobos-2.

A major problem, after New Horizons, is that our targets are more problematic. The public can follow the idea of missions to the moon, Mars, Venus, Pluto, etc. But Titan, Europa, Ceres, Vesta, Io, and the Kuiper Belt? Most people have never even heard of the these places, including Congress. We are eating the fruit of decades of bad science education.

Galileo WOULD have launched in '86 were it not for the Challenger accident though.

Doug

Good point, Doug. I think we need to be careful here in distinguishing between actual mission launches and project starts. A few U.S. planetary missions were initiated in the early to mid-1980's.

If you're in your 90's - you had Lindbergh.

You're so, so Wright, brother!

Bob Shaw

My grandmother, who worked as a secretary on Fifth Avenue in New York
City in the late 1920s, saw Lindbergh's ticker tape parade out the window of
her office after his famous trans-Atlantic flight in 1927.

Well, had it not been tied to the shuttle, it would have lauched in '81 or '82. And, had it not been for the "everything goes by shuttle" rule, Magellan would have probably launched sooner too. But, due to bad management, the 80's, save 1989, saw no planetary launches. I would view this differently if Galileo in any way needed the Shuttle for technical reasons, not political/bureaucratic ones.

I believe Magellan was only slightly delayed by the Challenger loss. If I remember correctly, its original launch date was ca. 1988. And VOIR was cancelled pre-Challenger loss.

Thank you for the correction, Alex. Memory is going - I can feel it.

Regarding probe missions originating in the 1980s, I feel I must
emphasize the Venera and Vega missions. These probes produced
the first color images of Venus' surface (and the last actual images
of that planet's surface from the surface to date) plus the only balloon
probes of Venus' atmosphere - or any other world's atmosphere to
date.

In addition to the first flybys of Comet Halley and the first balloons on
Venus (plus two landers), had Vega 1 and 2 not been so low on fuel, they
would have performed the first distant flyby (about 600,000 miles) of a
planetoid, Adonis (BIS Spaceflight article on Soviet Venus missions, 1992).

Yes, I mentioned those in my earlier post too, but they don't factor in when discussing the handling of U.S. dollars. My point isn't that the Challenger caused the delay of all these missions, but the Shuttle program in general - having to be launched on the shuttle made them more expensive.

Andrew Lawler has an excellent article ("A Space Race to the Bottom Line") in the March 17, 2006, issue of Science about last week's meeting (in Washington, D.C.) of the National Academies' Space Studies Board:

Here's an excerpt:

"Short of an abrupt cancellation of the shuttle and station programs, there are few prospects for a dramatic change in science's fortunes. Indeed, this year's overall increase of 3.2% for NASA may look good in a few years, board members fear. And even if the shuttle is retired in 2010 once the space station is complete, the space agency's budget documents note that the dividends will go into the exploration program rather than science.

"'We're not going to be able to execute the decadal [studies] as they exist,' concludes Lennard Fisk, board chair and a geophysicist at the University of Michigan, Ann Arbor. A 1% increase in NASA's science budget, he says, translates into 'a major retrenchment.' And scientists say they would rather make the hard choices than leave them to NASA managers. If they don't, Blandford warns, 'choices that should be scientific and technical will be left to the political process.'

"After hours of discussion, board members broadly agreed to protect research funds for the university community and for smaller missions. That decision puts larger efforts in each discipline on the chopping block. Moore suggested that to find earth science savings, the $430 million Landsat mission slated for launch by 2010 could be reviewed, and astronomers privately and cautiously suggest that deferring JWST by a few years could rescue smaller astrophysics missions in the near term. The largest planetary mission now scheduled is the Mars Science Laboratory, slated for a 2009 launch; among solar physicists, the big-ticket item is the Solar Dynamics Observatory due for orbit in 2008."

Yeah, before we start sniffling too much about our cruel mistreatment, we really should keep in mind that the situation right now is not even remotely comparable to the genuine desert of the 1980s. We are now in the Second Golden Age of Solar System Exploration -- just a brief look at what's happened or is scheduled to happen this year alone makes that clear. We could, however, be doing even better.

Damn right, Bruce.

Active interplanetary spacecraft currently returning science data, not counting those in orbital storage or science spacecraft in solar orbit:

1. Messenger
2. Venus Express
3. SMART-1
4. Ulysses
5. MGS
6. Mars Odyssey
7. MRO
8. Mars Express
9. Spirit
10. Opportunity
11. New Horizons
12. Cassini
13. Voyager 1
14. Voyager 2
(15. Hayabusa)

Bob Shaw

As a boy, my dad (who worked as a quality control manager on Apollo .. His inspectors signed off on the LM Ascent engines...) watched from a window in the Flatiron building in Manhattan as they held the grand parade for the boys coming home from "over there". That's a bit before Lindberg.

Wow. What was that like, countdown to ignition? Confidence, or terror?

Good list...you could also add Stardust and Deep Impact in parentheses, given their possible extensions.

Mark Peplow has an update in his LPSC blog.

Definitely some wisdom there, and let's face it: In this new budgetary climate, it's time to go for the low-hanging fruit.

Based on our best current information, an Enceladus landing/investigation is much less daunting from a complexity and risk perspective than going to Europa, and therefore it might be much more palatible to the "suits"...and quite possibly cheaper. If nothing else, an Enceladus lander would undoubtedly refine the technologies needed to tackle Europa with less mission risk.

Rosetta is another.

Aaargh! How could I have, er, you know? Damn.

Bob Shaw

I'll bet this "Mars Mafia" sits around and endlessly reinforces their own notions that we ought to cancel all non-Mars planetary exploration, on the theory that all the money that's being "wasted" on these flagship missions to non-Mars destinations will automatically get spent on more Mars probes -- eh, Bruce?

-the other Doug

Emily Lakdawalla's latest blog entry has a characteristically thorough and insightful discussion of the debate over outer planets exploration strategies. I would love to see the graphics she refers to, especially the diagram prepared by Torrence Johnson.

I'll take this opportunity to agree with the Cosmic Rocker's comment that "Emily's blog has become _the_ blog to read for the latest summary of planetary news." The level of detail she provides permits "planet spotters" to have a sense of vicarious participation in the business of planetary science that would otherwise be very difficult to achieve. Lots of us are jealous of her job, but it's hard to imagine anyone doing it better.

TTT