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Unmanned Spaceflight.com _ Jupiter _ Is Europa really the "highest priority" of the community?

Posted by: mcaplinger Mar 15 2006, 05:50 PM

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.

Posted by: elakdawalla Mar 15 2006, 07:19 PM

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

Posted by: djellison Mar 15 2006, 07:29 PM

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

Posted by: AlexBlackwell Mar 15 2006, 07:31 PM

QUOTE (mcaplinger @ Mar 15 2006, 05:50 PM) *
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.

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 tongue.gif

As for the substance of your post...

QUOTE (mcaplinger @ Mar 15 2006, 05:50 PM) *
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.)

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.

Posted by: paxdan Mar 15 2006, 07:34 PM

QUOTE (djellison @ Mar 15 2006, 07:29 PM) *
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

where is their Voyager?


On its way to Pluto at the moment.

Posted by: AlexBlackwell Mar 15 2006, 07:43 PM

QUOTE (elakdawalla @ Mar 15 2006, 07:19 PM) *
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.

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.

QUOTE (elakdawalla @ Mar 15 2006, 07:19 PM) *
Doesn't look like NASA's too interested in considering large missions at all right now though.

True, which may make all of this debate moot.

Posted by: djellison Mar 15 2006, 07:53 PM

QUOTE (paxdan @ Mar 15 2006, 07:34 PM) *
On its way to Pluto at the moment.


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.

Posted by: Marz Mar 15 2006, 08:04 PM

QUOTE (elakdawalla @ Mar 15 2006, 01:19 PM) *
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.


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? wink.gif 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!!

Posted by: BruceMoomaw Mar 15 2006, 10:43 PM

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_meeting/meeting_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.

Posted by: AlexBlackwell Mar 15 2006, 10:58 PM

QUOTE (BruceMoomaw @ Mar 15 2006, 10:43 PM) *
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_meeting/meeting_report.pdf '. pg 2. OPAG officially ranks Titan second, above Neptune.)...


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...").

Posted by: elakdawalla Mar 15 2006, 11:22 PM

QUOTE (BruceMoomaw @ Mar 15 2006, 02:43 PM) *
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_meeting/meeting_report.pdf '. pg 2. OPAG officially ranks Titan second, above Neptune.) Lunine, in short, was engaged in trouble-making, and Pappalardo was entirely justified to do 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.

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

Posted by: AlexBlackwell Mar 15 2006, 11:56 PM

QUOTE (elakdawalla @ Mar 15 2006, 11:22 PM) *
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 could be sent to Titan with only two instruments: a radar mapper capable of 100-meter resolution and a 2-micron imager.

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?

Posted by: nprev Mar 16 2006, 12:45 AM

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.

Posted by: JRehling Mar 16 2006, 01:26 AM

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.

Posted by: elakdawalla Mar 16 2006, 01:46 AM

QUOTE (AlexBlackwell @ Mar 15 2006, 03:56 PM) *
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?

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

Posted by: AlexBlackwell Mar 16 2006, 01:53 AM

QUOTE (elakdawalla @ Mar 16 2006, 01:46 AM) *
Such a mission would never get done this decade, so it's not incompatible with their citing the decadal survey.

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.

Posted by: elakdawalla Mar 16 2006, 01:57 AM

QUOTE (AlexBlackwell @ Mar 15 2006, 05:53 PM) *
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

Posted by: AlexBlackwell Mar 16 2006, 02:05 AM

QUOTE (elakdawalla @ Mar 16 2006, 01:57 AM) *
True. I guess I meant "started," but the point is well made that the 2010s will be a decade without a flagship mission.

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? biggrin.gif). 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.

Posted by: BruceMoomaw Mar 16 2006, 02:14 AM

QUOTE (mcaplinger @ Mar 15 2006, 05:50 PM) *
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.)


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.

Posted by: elakdawalla Mar 16 2006, 02:27 AM

QUOTE (AlexBlackwell @ Mar 15 2006, 06:05 PM) *
As for the Decadal Survey, I wasn't trying to be argumentative (Who? Me? biggrin.gif). 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.

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

Posted by: BruceMoomaw Mar 16 2006, 03:00 AM

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_meeting/titan_work_grp.pdf . See also pg. 16-30 of http://www.lpi.usra.edu/opag/jun_05_meeting/presentations/opagtitan.pdf , and the orbiter part of the proposal in http://www.lpi.usra.edu/opag/oct_05_meeting/langley_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.

Posted by: Stephen Mar 16 2006, 04:51 AM

QUOTE (elakdawalla @ Mar 15 2006, 07:19 PM) *
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.
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

Posted by: vjkane2000 Mar 16 2006, 04:58 AM

QUOTE (BruceMoomaw @ Mar 15 2006, 08:00 PM) *
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.


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.

Posted by: gpurcell Mar 16 2006, 01:57 PM

QUOTE (djellison @ Mar 15 2006, 07:29 PM) *
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


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

Posted by: ljk4-1 Mar 16 2006, 02:27 PM

QUOTE (gpurcell @ Mar 16 2006, 08:57 AM) *
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.

Posted by: elakdawalla Mar 16 2006, 02:57 PM

QUOTE (gpurcell @ Mar 16 2006, 05:57 AM) *
Well, I'm in my 30s and what I mainly remember is the long, long gap with NOTHING in the 1980s.

...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

Posted by: remcook Mar 16 2006, 03:37 PM

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

Posted by: AlexBlackwell Mar 16 2006, 04:12 PM

QUOTE (ljk4-1 @ Mar 16 2006, 02:27 PM) *
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.

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

Posted by: tedstryk Mar 16 2006, 04:22 PM

QUOTE (djellison @ Mar 15 2006, 07:29 PM) *
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

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.

Posted by: djellison Mar 16 2006, 04:26 PM

QUOTE (gpurcell @ Mar 16 2006, 01:57 PM) *
long gap with NOTHING in the 1980s.


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

Doug

Posted by: AlexBlackwell Mar 16 2006, 04:33 PM

QUOTE (djellison @ Mar 16 2006, 04:26 PM) *
Galileo WOULD have launched in '86 were it not for the Challenger accident though.

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.

Posted by: JRehling Mar 16 2006, 04:46 PM

QUOTE (tedstryk @ Mar 16 2006, 08:22 AM) *
If you're in your 60's - you had Apollo.


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

Posted by: Bob Shaw Mar 16 2006, 04:47 PM

QUOTE (JRehling @ Mar 16 2006, 04:46 PM) *
If you're in your 90's - you had Lindbergh.
biggrin.gif


You're so, so Wright, brother!

Bob Shaw

Posted by: ljk4-1 Mar 16 2006, 05:12 PM

QUOTE (JRehling @ Mar 16 2006, 11:46 AM) *
If you're in your 90's - you had Lindbergh.
biggrin.gif


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.

Posted by: tedstryk Mar 16 2006, 05:28 PM

QUOTE (djellison @ Mar 16 2006, 04:26 PM) *
Galileo WOULD have launched in '86 were it not for the Challenger accident though.

Doug

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.

Posted by: AlexBlackwell Mar 16 2006, 05:33 PM

QUOTE (tedstryk @ Mar 16 2006, 05:28 PM) *
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.

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.

Posted by: ljk4-1 Mar 16 2006, 05:36 PM

QUOTE (AlexBlackwell @ Mar 16 2006, 11:12 AM) *
Not to be pedantic but Magellan launched five months before Galileo. It's true, though, that the latter was started first.


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).

Posted by: tedstryk Mar 16 2006, 09:15 PM

QUOTE (ljk4-1 @ Mar 16 2006, 05:36 PM) *
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.

Posted by: AlexBlackwell Mar 16 2006, 09:31 PM

Andrew Lawler has an excellent article ("http://www.sciencemag.org/cgi/content/summary/311/5767/1540") 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."

Posted by: BruceMoomaw Mar 17 2006, 04:33 AM

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.

Posted by: Bob Shaw Mar 17 2006, 08:26 AM

QUOTE (BruceMoomaw @ Mar 17 2006, 04:33 AM) *
We are now in the Second Golden Age of Solar System Exploration...


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

Posted by: edstrick Mar 17 2006, 09:52 AM

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.

Posted by: centsworth_II Mar 17 2006, 01:06 PM

QUOTE (edstrick @ Mar 17 2006, 04:52 AM) *
His inspectors signed off on the LM Ascent engines


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

Posted by: tedstryk Mar 17 2006, 03:40 PM

QUOTE (Bob Shaw @ Mar 17 2006, 08:26 AM) *
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


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

Posted by: AlexBlackwell Mar 18 2006, 12:47 AM

Mark Peplow has an http://blogs.nature.com/news/blog/2006/03/lpsc_attempt_no_landing_there.html in his LPSC blog.

Posted by: nprev Mar 18 2006, 01:40 AM

QUOTE (AlexBlackwell @ Mar 17 2006, 04:47 PM) *
Mark Peplow has an http://blogs.nature.com/news/blog/2006/03/lpsc_attempt_no_landing_there.html 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.

Posted by: mchan Mar 18 2006, 04:55 AM

QUOTE (tedstryk @ Mar 17 2006, 07:40 AM) *
Good list...you could also add Stardust and Deep Impact in parentheses, given their possible extensions.


Rosetta is another.

Posted by: Bob Shaw Mar 18 2006, 01:39 PM

QUOTE (mchan @ Mar 18 2006, 04:55 AM) *
Rosetta is another.



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

Bob Shaw

Posted by: dvandorn Mar 18 2006, 04:50 PM

QUOTE (BruceMoomaw @ Mar 15 2006, 08:14 PM) *
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".)

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

Posted by: Tom Tamlyn Mar 18 2006, 04:57 PM

Emily Lakdawalla's latest http://www.planetary.org/blog/article/00000500/ 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 http://www.unmannedspaceflight.com/index.php?s=&showtopic=2354&view=findpost&p=46062 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

Posted by: Bob Shaw Mar 18 2006, 05:35 PM

An improved version of the list:


Active interplanetary spacecraft currently returning science data:

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. Rosetta
13. Cassini
14. Voyager 1
15. Voyager 2

Semi-active interplanetary spacecraft:
16. Hayabusa

Spacecraft in orbital storage, with potential for extended missions:
17. Deep Impact
18. Stardust

Spacecraft in orbital storage, with no planned extended mission:
19. Genesis

The list does not include science spacecraft in Solar orbit; those included have all had, or are planned to have, at least one encounter with a body other than the Earth.

Bob Shaw

Posted by: ljk4-1 Mar 18 2006, 05:49 PM

Though it has not been heard from since 2000, Pioneer 6 may still
be phoning home solar data since its launch in 1965:

http://www.space.com/news/spaceagencies/pioneer_6_contact_001209.html

http://en.wikipedia.org/wiki/Pioneer_6

Posted by: BruceMoomaw Mar 19 2006, 12:54 AM

QUOTE (dvandorn @ Mar 18 2006, 04:50 PM) *
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



Well, they're certainly trying to maximize spending on Mars probes at the expense of other planetary exploration and space science. That's why they're called the "Mars Mafia", after all. And, no, they don't think that "all" the money spent on other types of space science would go to Mars probes if those other space science missions were cancelled -- any more than I think that "all" the money spent on the manned space program would go to the unmanned space program if the manned program were cancelled. They just realize, like any sensible person, that a significant slice of it would.

Posted by: BruceMoomaw Mar 19 2006, 01:22 AM

QUOTE (Tom Tamlyn @ Mar 18 2006, 04:57 PM) *
Emily Lakdawalla's latest http://www.planetary.org/blog/article/00000500/ 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 http://www.unmannedspaceflight.com/index.php?s=&showtopic=2354&view=findpost&p=46062 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


It was an excellent piece of work -- and I also agree with the conclusion the group seems to be trending toward. Namely, that we already KNOW what the next necessary step is in exploring Europa -- the Orbiter -- whereas we don't have any clear idea yet what we should do at Titan and/or Enceladus, and will need several more years of Cassini observations to decide. Therefore, first things first: unless Cassini turns up something really spectacular and radical -- and the only thing I can think of that might adequately upset the applecart would be the discovery by Cassini of very complex organics in Enceladus' plume -- we should proceed with pushing Europa Orbiter first.

(That's where Flagship-class missions are concerned. The one other possibility -- finding valid New Frontiers-class missions to send to any of those three worlds -- is an entirely separate matter anyway, and will be handled separately.)

Posted by: elakdawalla Mar 19 2006, 06:42 AM

Aw, shucks, guys... rolleyes.gif

I think only very few diehard Titan fans would seriously advocate Titan over Europa today, for the reasons thoroughly covered by Torrence. Europa first, then Titan. But I sure hope we don't have to wait for the CEV to be developed before another flagship mission is started. If that happens, by that time Europa may well have some tough competition.

I've still got my Hayabusa notes to write up...stay tuned for that (but probably not until after the weekend).

--Emily

Posted by: Mariner9 Mar 19 2006, 08:53 PM

This whole situation reminds me a lot of the early 80s. I will admit that we are in much better shape on the whole, with many missions flying, and several in developement. But in one reguard it seems like history repeating itself. The planetary scientists are obsessed with one mission, and a very expensive mission it is. They keep pushing it, and are circling the wagons insisting it is the one true next step. Yet the message continues to be from above: we can't fund a mission that big right now.

Well, that was about where we were with the Mars Sample Return mission in the post Viking years. Everyone kept pushing big missions, and the biggest was MSR. It took major pressure from NASA headquarters (and Congress) to get the point across that MSR wasn't going to happen as the next mission to Mars, and wasn't there something, anything, that could fly in the meantime.

Eventually NASA scaled back on Venus Radar Mapper... and Magellen was approved. Only a year later Mars Observer was approved. They were the first new starts in seven years, and the only happened because political reality was finally admitted, and NASA submitted missions that were low enough cost to fit within the current budget reality.

I agree with someone earlier who stated that it's one thing to get a 600 million dollar New Horizons Pluto mission approved by grass roots lobbying, but quite another to get a Flagship mission approved using the same game plan.

If history is a guide here, I'd think the best move at this point would be for the OPAG and like minded scientists to accept that a 1.4 billion dollar mission just is not going to happen. But a 700-800 million dollar mission might stand a chance.

Better to focus on moving up the next New Frontiers mission and having the competition be based on Outer planets only (Comets and Venus will have to wait). There is still a LOT that a Galileo type tour of the Jovian system could teach us, not only about Europa but also Io and the rest.

Posted by: mcaplinger Mar 19 2006, 09:07 PM

QUOTE (Tom Tamlyn @ Mar 18 2006, 08:57 AM) *
Emily Lakdawalla's latest http://www.planetary.org/blog/article/00000500/ has a characteristically thorough and insightful discussion of the debate over outer planets exploration strategies.

I wonder if one problem is that both Galileo and Cassini have been very expensive missions. I think the OP community might have been better served by a larger number of somewhat smaller missions. Unfortunately the FBC pendulum has swung far away from smaller missions, and it is hard to build constituencies for them -- big missions tend to force coalitions between groups that otherwise would be competing for the same resources.

Posted by: BruceMoomaw Mar 20 2006, 01:42 AM

There are other problems with running small missions to the outer System. First, the outer System is just unavoidably bloody hard and expensive to explore -- only one Discovery finalist has ever been aimed at an outer world, and it isn't that easy to properly explore them even with New Frontiers-class missions.

Second, the things we have been trying to observe -- unlike those in the inner System -- usually comprise miniature solar systems in their own right, and they include a hell of a lot of different types of physical phenomena that are going on simultaneously and interacting with each other, so that you need simultaneous observations of them with a large number of different instruments to properly understand them. It's not impossible to break them up -- Galileo and Cassini, for instance, could theoretically have been broken up into three missions each, consisting of an entry probe, a spin-stabilized magnetospheric orbiter, and a fully stabilized remote-sensing orbiter -- but the total cost of all this is a lot higher than for a single unified craft, and again you're going to miss some important simultaneous overlapping observations from instruments on the three separate missions.

Third, the gap between missions to an outer world is so damn unavoidably long. If you find something interesting from an initial simple and low-cost outer-world spacecraft that is worthy of investigation with another type of instruments, then, no matter how much funding you've got, you have to twiddle your thumbs for YEARS, or decades, before that additional set of instruments can get there -- which provides another strong motive to carry as many different kinds of instruments as you can on the very first mission.

Posted by: Stephen Mar 20 2006, 10:31 AM

QUOTE (Mariner9 @ Mar 19 2006, 08:53 PM) *
I agree with someone earlier who stated that it's one thing to get a 600 million dollar New Horizons Pluto mission approved by grass roots lobbying, but quite another to get a Flagship mission approved using the same game plan.

If history is a guide here, I'd think the best move at this point would be for the OPAG and like minded scientists to accept that a 1.4 billion dollar mission just is not going to happen. But a 700-800 million dollar mission might stand a chance.

Better to focus on moving up the next New Frontiers mission and having the competition be based on Outer planets only (Comets and Venus will have to wait). There is still a LOT that a Galileo type tour of the Jovian system could teach us, not only about Europa but also Io and the rest.
But would such a mission tell us anything significantly more about Europa that would allow NASA to drop the need for a dedicated Europa orbiter and go straight to the lander-cum-borer-cum-diver mission? If there still needs to be an EO first somewhere down the track wouldn't that make another Galileo-type-tour, for all the useful science it might acquire, merely a stopgap mission?

======
Stephen

Posted by: ugordan Mar 20 2006, 01:15 PM

QUOTE (Stephen @ Mar 20 2006, 11:31 AM) *
But would such a mission tell us anything significantly more about Europa that would allow NASA to drop the need for a dedicated Europa orbiter and go straight to the lander-cum-borer-cum-diver mission? If there still needs to be an EO first somewhere down the track wouldn't that make another Galileo-type-tour, for all the useful science it might acquire, merely a stopgap mission?

Actually, the proposal for EO was that it would spend something like a year and a half doing a Galileo-type tour of the 3 Galileans, adjusting its orbit in preparation for Europa orbit insertion and then the primary science phase would begin, lasting 'only' a month or so. So you already get a tour with the orbiter as is. A dedicated tour-only mission seems like a waste of time and resources in that light.

Posted by: JamesFox Mar 20 2006, 01:29 PM

QUOTE (Stephen @ Mar 20 2006, 05:31 AM) *
But would such a mission tell us anything significantly more about Europa that would allow NASA to drop the need for a dedicated Europa orbiter and go straight to the lander-cum-borer-cum-diver mission? If there still needs to be an EO first somewhere down the track wouldn't that make another Galileo-type-tour, for all the useful science it might acquire, merely a stopgap mission?


If a stopgap mission is all that can be afforded, then better a stopgap mission than nothing. Also, Europa is far from the only Moon in the Jovian system that needs follow-up missions. Admittedly, the lack of RTG's on a low-cost mission would probably make close-up observations of Io or Europa more difficult, which would probably reduce the appeal of a low cost mission...

Posted by: mcaplinger Mar 20 2006, 03:49 PM

QUOTE (BruceMoomaw @ Mar 19 2006, 05:42 PM) *
First, the outer System is just unavoidably bloody hard and expensive to explore...

Just because, e.g., Galileo was expensive (and I don't know what the total runout cost was but $4B wouldn't surprise me) doesn't mean that a properly-designed reduced-scope mission would have to be. I'm not talking about orders of magnitude less cost, but 2-3x doesn't seem impossible, if there was in fact much real motivation to save money.
QUOTE
Second, the things we have been trying to observe -- unlike those in the inner System -- usually comprise miniature solar systems in their own right, and they include a hell of a lot of different types of physical phenomena that are going on simultaneously and interacting with each other, so that you need simultaneous observations of them with a large number of different instruments to properly understand them.

That's the party line, but I'd be prepared to argue that Cassini could lose half of its instrument complement without losing half its science. If instruments alone were a huge cost fraction of a mission (they're usually less than 25%, maybe more like 10%), that might be important.

Posted by: djellison Mar 20 2006, 04:02 PM

I wonder what might be feasable using the Juno platform, but augmented with a larger capacity for Delta V - perhaps under an New Frontiers budget.


Doug

Posted by: Mariner9 Mar 20 2006, 04:29 PM

Is one Europa orbiter more cost effective than 3 lower cost missions? Yes it is, I'll admit it.

In fact, there are some things (like laser altimetry measuring the tidal flex of the moon) that are just not going to happen unless you go into orbit. So It wouldn't be 3 lower cost missions, more like 1-2 lower cost missions and you end up eventually coughing up the dough for the Europa Orbiter anyway.

And the argument "the missions are so few and far between we have to have the largest ship we can manage in each mission" .... remember my point about MSR in the late 70s early 80s? Well, the "get the most out of each mission" argument was bandied about a lot in those days. The result was (with the growing Shuttle budget helping) no launches for over 10 years.

With CEV swallowing everything in sight, we could push for Europa for years, and end up always just teetering on the brink of a new start, then loosing it in the next budget crunch.


So in my mind, another JUNO in the hand is worth 2 Flagships in the bush.

Posted by: Bjorn Jonsson Mar 20 2006, 04:29 PM

Regarding EO vs. Galileo vs. a 'Galileo 2' vs. Juno vs. a New Frontiers class Jupiter orbiter let's not forget that a Galileo satellite flyby and a satellite flyby by a 'modern' orbiter are two completely different things. An orbiter equipped with carefully selected instruments and a large solid-state recorder can acquire a lot more data (both in terms of quantity and quality) during a single flyby of e.g. Europa than Galileo did over its entire mission (with the obvious exception that you see only one lit hemisphere at most during a single flyby). This is true even if the modern orbiter is smaller and less expensive than Galileo. For example a datarate on the order of a few kbps (compared to Galileo's originally inteneded 100+ kbps) would be sufficient to accomplish a very respectable mission although more is always better.

Collaboration with ESA has sometimes been mentioned as a possible way to reduce (or rather to distribute) costs. Does anyone know if this is even practical today (as opposed to when Cassini-Huygens was being designed and constructed) because of ITAR ?

Posted by: Mariner9 Mar 20 2006, 04:45 PM

One last point.


Viking was scaled down from original plans to use Saturn 1B or even a Saturn V for a multi launch of a much larger probe.

Voyager was the scaled down compromise when TOPS was canceled in the early 70s.

NEAR was the 150 million dollar scaled down compromise when the endlessly studied 500 million dollar JPL asteroid mission couldn't get a new start.







OK, I lied. Just two more points.


I agree with the "modern orbiter" argument. Can you imagine what multiple flybys of Europa could accomplish with a HIRISE ????????

I admit we're talking a bit over the New Fronteirs budget. But we are not talking flagship costs.

Imagine such a vehicle making multiple passes of Io. .... live volcanos, direct sampling of the plumes ..... congressmen love pretty pictures, and the public may not care the least about gravity field mapping, but they understand massive volcanoes.

Posted by: AlexBlackwell Mar 20 2006, 05:58 PM

QUOTE (BruceMoomaw @ Mar 19 2006, 01:22 AM) *
It was an excellent piece of work...

I'll second that motion. And I'll go even further: Emily's LPSC coverage this year has been the best I've ever seen for that event, even ahead of Kerr's typically good LPSC pieces in Science.

Posted by: BruceMoomaw Mar 20 2006, 06:19 PM

This is turning into an awfully interesting debate, and I need to put in some more thought on it. So for now I'll just mention that consideration is apparently being given to adding one more instrument to Juno's payload: a combination near-IR spectrometer and camera.
http://www.lpi.usra.edu/meetings/lpsc2006/pdf/1564.pdf

Looking at it again: during Juno's (brief) extended mission, this gadget might -- repeat, MIGHT -- provide justification for having the craft make one close flyby of Io, to get the detailed mineralogical data that Galileo couldn't get because of the last-second partial failure of its own NIMS, and to map hotspots on Io better. This is a longshot, though -- their primary concern is making sure that the craft is destroyed before it has any chance to hit Europa.

Posted by: AlexBlackwell Mar 20 2006, 09:10 PM

QUOTE (BruceMoomaw @ Mar 20 2006, 06:19 PM) *
This is turning into an awfully interesting debate, and I need to put in some more thought on it.

Yes, it's a good thread with several good thoughts scattered throughout the posts.

Posted by: AlexBlackwell Mar 20 2006, 10:01 PM

QUOTE (AlexBlackwell @ Mar 20 2006, 09:10 PM) *
Yes, it's a good thread with several good thoughts scattered throughout the posts.

Torrence Johnson et al. have an interesting http://www.cosis.net/abstracts/COSPAR2006/02535/COSPAR2006-A-02535.pdf for COSPAR 2006.

Posted by: JRehling Mar 20 2006, 10:32 PM

This has been insightful.

Europa currently has large advantages in what I would call "programatic" factors: The science has been digested, and the priorities have largely been evaluated. Enceladus and Titan won't catch up for a while. As it stands now, Europa should clearly get the next mission.

However, if CEV and other factors keep us from flying a Europa mission for long enough, some of those advantages will evaporate. If we find ourselves in the unfortunate circumstance of being 10 years past Cassini's death and nothing has flown yet, Enceladus or Titan could catch up in terms of Cassini science having been assimilated, and either of them might prove to be easier missions that Europa. Then Europa's only advantages might be that it has been a subject for exploration longer and that the other Galileans would benefit from the tour leading to Europa orbit.

Posted by: Stephen Mar 21 2006, 12:41 AM

QUOTE (BruceMoomaw @ Mar 20 2006, 06:19 PM) *
This is turning into an awfully interesting debate, and I need to put in some more thought on it. So for now I'll just mention that consideration is apparently being given to adding one more instrument to Juno's payload: a combination near-IR spectrometer and camera.
http://www.lpi.usra.edu/meetings/lpsc2006/pdf/1564.pdf

Looking at it again: during Juno's (brief) extended mission, this gadget might -- repeat, MIGHT -- provide justification for having the craft make one close flyby of Io, to get the detailed mineralogical data that Galileo couldn't get because of the last-second partial failure of its own NIMS, and to map hotspots on Io better. This is a longshot, though -- their primary concern is making sure that the craft is destroyed before it has any chance to hit Europa.
What are the chances of it achieving the latter by doing a Ranger-style kamikazi swan dive straight into Io, snapping pics etc all the way down to the surface?

======
Stephen

Posted by: AlexBlackwell Mar 21 2006, 12:48 AM

QUOTE (Stephen @ Mar 21 2006, 12:41 AM) *
What are the chances of it achieving the latter by doing a Range-style kamikazi swan dive straight into Io, snapping pics et all all the way down

That would be cool, and reminiscent of one of the original (ca. 1979) end-of-mission scenarios for Galileo.

Posted by: BruceMoomaw Mar 21 2006, 02:49 AM

I very much doubt it could transmit them fast enough; its bit rate is far lower than Galileo's would have been had it worked right. (After all, most of Juno's data is non-imaging, and it's supposed to transmit back its relatively small amount of imaging data at its leisure.) I'll recheck its bit rate, but I believe it's no more than about 8000 bps. For that matter, I'm not even sure that they can set up a close flyby of Io during its operating lifetime; I'll have to take another look at the chart of its orbital tilt at different times during its mission. Nor do I even know -- yet -- that it's even likely they'll put this instrument on it at all, although I intend to E-mail Scott Bolton tonight on the subject.

Since, however, one "Science" retrospective on Galileo did say that its biggest disappointment at Io was its failure to get any high-resolution mineral composition measurements, it would certainly be nice if they could pull this off.

Posted by: BruceMoomaw Mar 21 2006, 03:00 AM

This thing is apparently also quite a wide-angle camera, which means that -- even if it could send back photos live during a crash into Io -- the last ones it sent back would almost certainly be no better than Galileo's sharpest ones, and probably a good deal worse. (But the spectral resolution of the accompanying near-IR point spectrometer is twice as good as NIMS, over the 2 to 5 micron range, improving its mineralogical powers. And any near-IR thermal photos taken by the accompanying near-IR camera would surely be sharper than any thermal maps of Io made by either the NIMS or the PPR on Galileo.)

In any case, since it seems likely that it will be a long time before we get any kind of closeup look at Io again (Europa Orbiter wouldn't come near it, although it's now a long-shot possibility that the next New Frontiers mission selected may be a Jupiter-orbiting Io mapper), it seems worthwhile looking into any possibility.

Posted by: JRehling Mar 21 2006, 03:32 AM

QUOTE (BruceMoomaw @ Mar 20 2006, 07:00 PM) *
In any case, since it seems likely that it will be a long time before we get any kind of closeup look at Io again (Europa Orbiter wouldn't come near it, although it's now a long-shot possibility that the next New Frontiers mission selected may be a Jupiter-orbiting Io mapper), it seems worthwhile looking into any possibility.


I know the published "sample" trajectories for Europa Orbiter didn't feature a close Io flyby, but would it be possible to perform one before JOI on initial arrival? Well, obviously it's possible, but would it cost too much delta-v? I imagine it would involve flying past Io and then on to about Europa orbital radius before firing the engines. That would also start the clock ticking on the radiation survival lifetime, and briefly taking on more rads than the nominal mission, but only for hours. And the flyby would not have to be very close, either; it may be sufficient to "split the difference" between Io and Europa orbital distance to accomplish the main scientific goals.

Posted by: BruceMoomaw Mar 21 2006, 03:43 AM

Looks like my whole idea was another pipe dream. I can't find anything on Juno's bit rate, even in Steve Matousek's otherwise excellent description ( http://trs-new.jpl.nasa.gov/dspace/bitstream/2014/37654/1/05-2760.pdf ), although an earlier strawman description of a similar mission had a 4000 bps rate. However, a drawing on page 4 of Matousek's report makes it clear that -- throughout its 32-orbit primary mission -- Juno can't possibly make a close flyby of Io (or Europa). And any extended mission will last no more than a month or so, since they want to make damn sure that the craft doesn't malfunction from radiation before they can steer it into Jupiter and thus make sure of missing Europa -- in fact, they may even end its mission after only about 16 orbits or so if they think they have enough data by then. They could, I suppose, maybe arrange a close flyby of Io if they had one hell of a lot of spare delta-V, but I can't see how they could have enough fuel margin left for that. (On the bright side, just by having a spectral resolution twice as good as Galileo's, the near-IR spectrometer on Juno could get a little more long-range compositional data on Io.)

Posted by: BruceMoomaw Mar 21 2006, 03:53 AM

John Rehling's idea for Europa Orbiter just might be workable -- IF they want it badly enough.

EO, since it will now use a VEEGA gravity assist to get to Jupiter, will have a hell of a lot of payload margin -- about 340 kg worth (after it gets into Europa orbit), which is why they're considering a lander. An alternative use being very seriously considered for at least some of that mass margin is to instead increase its shielding, since EO can extend its lifetime in Europa orbit (currently 3 months) by 1 month for every 100 kg more shielding. An alternative use for that shielding could be to allow it to make a few close Io flybys before entering Europa orbit. However, this might also require additional propellant, depending on the design of its Jupiter-orbiting phase (the plan for EO, from the start, has been to have it make a gravity-assist flyby of Ganymede to help brake into Jupiter orbit, instead of using Io as Galileo did).

It's also true that the larger instrument payload they now plan for EO would be well-designed to study Io as well -- high-res and medium-res cameras, near-IR and mass spectrometers (and maybe X-ray and UV ones too), a thermal mapper, fields and particles instruments.

Posted by: BruceMoomaw Mar 21 2006, 04:03 AM

While I'm on the subject of Europa Orbiter and the Jovian radiation belts: one important factor in NASA's advisors saying that it's time to go ahead with the thing is that -- thanks to the additional shielding mass made possible by using inner-planet gravity assists to reach Jupiter -- it has now been decided that our existing technology is already adequate to provide it with the radiation-hard electronics it will need. This is also partly because a lot of additional work has been done in the last few years to develop rad-hard electronics, during the work on EO's previous lighter-weight incarnation and then on JIMO. The computer on Deep Impact and MRO can confidently withstand 1 Mrad, and a lot of other similarly hard new electronics have also been developed.

Using the VEEGA trajectory, by the way, TRIPLES the mass of EO compared to the direct-to-Jupiter trajectory which they (for reasons that baffle me) originally had planned for it.

Posted by: mcaplinger Mar 21 2006, 04:07 AM

QUOTE (BruceMoomaw @ Mar 20 2006, 08:03 PM) *
This is also partly because a lot of additional work has been done in the last few years to develop rad-hard electronics, during the work on EO's previous lighter-weight incarnation and then on JIMO. The computer on Deep Impact and MRO can confidently withstand 1 Mrad, and a lot of other similarly hard new electronics have also been developed.

Don't believe all the JPL hype. The RAD750 is only hard to ">100 Krad" and if they'd meant 1 Mrad, they'd have said that. And it's not all that obvious how you can build an Mrad-hard imager, though we'll do it if you toss a few million our way smile.gif

Posted by: BruceMoomaw Mar 21 2006, 04:34 AM

Well, that's what they kept assuring all of us (repeatedly) at the Europa meeting. It's not my fault if we were being fibbed to...

Posted by: mchan Mar 21 2006, 04:34 AM

QUOTE (BruceMoomaw @ Mar 20 2006, 08:03 PM) *
Using the VEEGA trajectory, by the way, TRIPLES the mass of EO compared to the direct-to-Jupiter trajectory which they (for reasons that baffle me) originally had planned for it.

Giving in to the no-nukes-in-space folks fears of the end of the world from an accidental re-entry during an Earth flyby?

Posted by: mcaplinger Mar 21 2006, 04:46 AM

QUOTE (BruceMoomaw @ Mar 20 2006, 08:34 PM) *
It's not my fault if we were being fibbed to...

It's arguably your fault if you state it as absolute truth without going to any effort to verify it, though.

Posted by: Stephen Mar 21 2006, 05:56 AM

QUOTE (BruceMoomaw @ Mar 21 2006, 03:43 AM) *
Looks like my whole idea was another pipe dream. I can't find anything on Juno's bit rate, even in Steve Matousek's otherwise excellent description ( http://trs-new.jpl.nasa.gov/dspace/bitstream/2014/37654/1/05-2760.pdf ), although an earlier strawman description of a similar mission had a 4000 bps rate.
That document alludes (p8) to the spacecraft using the Ka band (albeit: "For the GS measurements, Ka-up and downlink is only available from the DSN station Deep Space Station (DSS)-25 at Goldstone, California").

What bit rate would be expected from a Ka band link between Jupiter & Earth?

EDIT: I think I may have found the info to that last query in this PDF document, albeit maybe not specifically for Juno. Check out:

http://hrdd.grc.nasa.gov/resources/Pdfs/Outerplanetary.pdf

======
Stephen

Posted by: JRehling Mar 21 2006, 08:01 AM

QUOTE (mcaplinger @ Mar 20 2006, 08:07 PM) *
And it's not all that obvious how you can build an Mrad-hard imager


Vacuum tubes?

cool.gif

Posted by: dvandorn Mar 21 2006, 08:10 AM

Oh, gee -- that reminds me of an sf story I once read. It was written in the late '40s, and had its plucky 22nd-century-spaceship-pilot-hero turning on his ship's electronics and waiting, "as man had been forced to wait since the dawn of the electronic age, for the vacuum tubes to warm up."

biggrin.gif

-the other Doug (who is old enough to remember those TV tube sales carts and the joys of finding a given tube to replace one that had blown out...)

Posted by: edstrick Mar 21 2006, 09:02 AM

I last tested vaccuum tubes in the early 90's, keeping my mothers electric organ going. The only tube tester in town was at "Tinkertronics" and was very very tired, mechanically. Hard to get good tube pin contact and the like.

Posted by: AlexBlackwell Mar 21 2006, 06:35 PM

QUOTE (JRehling @ Mar 21 2006, 03:32 AM) *
I know the published "sample" trajectories for Europa Orbiter didn't feature a close Io flyby, but would it be possible to perform one before JOI on initial arrival? Well, obviously it's possible, but would it cost too much delta-v? I imagine it would involve flying past Io and then on to about Europa orbital radius before firing the engines.

Galileo did exactly the same thing: Io flyby->JOI->Perijove Raise Maneuver.

Posted by: djellison Mar 21 2006, 07:44 PM

I think JUNO might actually do harm for the 'Europan' cause.

Imagine the discussion up on the hill,

"They're pitching for a mission to Europa"
"Where's that?"
"It's one of the moons of Jupiter, the one that's made of icebergs or something"
"Didn't we just DO Jupiter with that JANO or JOURNO or something?"
"Hmm - you're right - I say we go somewhere else"

I'm sure JUNO is of excellent scientific value, but you can see it leading toward another pause in Jovian exploration.

Doug

Posted by: AlexBlackwell Mar 21 2006, 08:03 PM

QUOTE (djellison @ Mar 21 2006, 07:44 PM) *
I think JUNO might actually do harm for the 'Europan' cause...I'm sure JUNO is of excellent scientific value, but you can see it leading toward another pause in Jovian exploration.

I'm not too sure of this. The Level 1 science objectives in the Decadal Survey for the Flagship-class "Europa Geophysical Explorer" are very distinct from the New Frontiers-class "Jupiter Polar Orbiter with Probe(s)" aka Juno. While the latter may contribute second tier science for the former, and politicians might seize on this continue delaying a Europa mission, the EGE Level 1s remain. So as long as the scientists have any input in the process, I don't see Juno doing any real harm to a Europa mission.

Posted by: BruceMoomaw Mar 21 2006, 10:03 PM

QUOTE (mcaplinger @ Mar 21 2006, 04:46 AM) *
It's arguably your fault if you state it as absolute truth without going to any effort to verify it, though.


Hokay. Call me naive, but -- even given the number of times central NASA HQ has routinely lied to us -- the thought that JPL's (multiple) spokesmen might be deliberately lying through their teeth, not only to me but to all the scientists at that meeting, never occurred to me. (It never occurred to the scientists there, either. If Mike Caplinger can confirm that tidbit, they won't be very amused to learn about it.)

Posted by: BruceMoomaw Mar 21 2006, 10:36 PM

QUOTE (AlexBlackwell @ Mar 21 2006, 08:03 PM) *
I'm not too sure of this. The Level 1 science objectives in the Decadal Survey for the Flagship-class "Europa Geophysical Explorer" are very distinct from the New Frontiers-class "Jupiter Polar Orbiter with Probe(s)" aka Juno. While the latter may contribute second tier science for the former, and politicians might seize on this continue delaying a Europa mission, the EGE Level 1s remain. So as long as the scientists have any input in the process, I don't see Juno doing any real harm to a Europa mission.


Yeah. The thing about New Frontiers (and Discovery) is that they are on entirely separate funding tracks from the money provided for the unique Flagship missions, and the specific selection of missions to various Solar System targets for both those competitive programs is supposed to be wholly separate from the actual total amount of money provided to both programs. So -- unless an NF mission specifically takes a bite out of the science goals for Europa itself -- there should be no connection at all between the particular set of missions selected by the review board for the NF program, and the amount of funding that Europa Orbiter gets. Juno is entirely a nonbiological mission aimed at Jupiter itself -- not only will it not make any astrobiologcal studies, but the current plans are for it not to make any observations whatsoever of any of Jupiter's moons (and its orbit won't even let it come close to Europa, although theoretically they could set up close flybys of Ganymede or Callisto).

Concerning the distribution of money between big Flagship missions and smaller space-science missions as a whole, however, the OPAG site has just reprinted some useful new documents -- confirming that, if push comes to shove, space scientists prefer funding smaller missions (and providing general research & technology money) to funding bigger ones:
http://www.lpi.usra.edu/opag/science_cuts.pdf
http://www.lpi.usra.edu/opag/07_budget_bagenal.pdf
http://www.house.gov/science/hearings/full06/March%202/index.htm

I haven't looked at the last of those documents yet, but the heads of NASA's four current space science subdivisions all agree with the philosophy already noted by Emily: usually, the bigger individual projects are, the LESS scientifically cost-effective they are. They prefer -- in order of priority -- research, then technology development, then small missions, then medium-sized ones, then flagship ones.

But the main flagship projects for the Universe and Sun-Earth divisions -- the Webb Telescope and the Solar Dynamics Observatory -- are already well underway, and cutting their funding now would just prolong the total length of the projects and thus increase their total cost. And the Earth Science division's flagship, the GPMM mission, has already been repeatedly delayed, so the director of that branch says he'd prefer instead to delay the somewhat cheaper Landsat replacement. By contrast, the Solar System (non-Mars) division's main flagship mission, Europa Orbiter, hasn't been started yet, and so delaying it is much more practical. (We could also consider delaying MSL -- since it's just getting started -- but Mars missions remain one of NASA's Holy of Holies.) One should also consider Fran Bagenal's comment: "I feel on thin ice asking for additional funds -- new money -- when a second glance at the NASA budget reveals the current rhino in the room to be the fact that we have lost control of mission cost growth."

So perhaps what we should be focusing on right now is: are there any ingenious new ways to explore the moons of the outer satellites with New Frontiers-class missions? The traditional line has been that there aren't, but then this has been based on a confidence that Flagship-class missions WILL be flown to them. The loss of those makes a careful reexamination of ideas for NF-class missions to the outer-System moons -- ANY of them -- worthwhile again.

Posted by: JRehling Mar 21 2006, 10:54 PM

QUOTE (BruceMoomaw @ Mar 21 2006, 02:36 PM) *
So perhaps what we should be focusing on right now is: are there any ingenious new ways to explore the moons of the outer satellites with New Frontiers-class missions? The traditional line has been that there aren't, but then this has been based on a confidence that Flagship-class missions WILL be flown to them. The loss of those makes a careful reexamination of ideas for NF-class missions to the outer-System moons -- ANY of them -- worthwhile again.


Tight as money is, I'm not convinced that mission funding is not in that nonlinear zone that government specializes in, where it's not necessarily twice as hard to get money for something twice as expensive. So maybe the flagship/NF distinction is misleading.

But I would certainly think that a free/cheap-return flyby sampler of Enceladus's plumes could be done in the NF budget. Would it be possible to do this with solar panels plus batteries and extensive use of "sleep" mode? Sampling Titan's upper atmosphere would seem to be possible, but less obviously desirable. Seems to me that any Enceladus-sniffing mission has to cross Titan's orbit twice anyway, so in principle, it's doable. In fact, given that you could have this craft lose velocity and still back to Earth, an aero-braking pass through Titan's atmosphere might even be the thing to make it work! This all seems possible, but screaming of super-tight engineering constraints. A double sample return on a budget would be a stunning success, and any remote sensing that rode along would be bonus. Note that this craft would also cross the orbit of most of Saturn's other satellites twice -- including Iapetus. Barring constraints with Iapetus's inclination and obvious geometric constraints, and the fact that Cassini might just finish the Iapetus saga...

Imagine a one-shot mission that flies on the cheap, wakes up just to image Iapetus's most intriguing terrain that Cassini doesn't get around to (this could also happen on the out-leg), samples Titan's upper atmosphere, images the Tiger Stripes up-close while sampling Enceladus's plumes, and returning the two samples to Earth. The proponents of whatever mission this was competing with would have to get a little sweat on their foreheads.

Posted by: JamesFox Mar 21 2006, 11:17 PM

What I was thinking of myself, is pretty much a New-Frontiers class moden mini-version of Galileo: a smallish Jovian orbiter with one RTG or solar panels, designed to study the Galilean moons via sucessive flybys. With the faliure of Galileo's HGA, even a little orbiter with modern instruments could easily outstrip Galileo in the volume and quality of the data returned. It might lack charisma, but it might be the logical replacement for a Europa Orbiter that cannot be afforded.

Posted by: nprev Mar 21 2006, 11:33 PM

QUOTE (JamesFox @ Mar 21 2006, 03:17 PM) *
What I was thinking of myself, is pretty much a New-Frontiers class moden mini-version of Galileo: a smallish Jovian orbiter with one RTG or solar panels, designed to study the Galilean moons via sucessive flybys. With the faliure of Galileo's HGA, even a little orbiter with modern instruments could easily outstrip Galileo in the volume and quality of the data returned. It might lack charisma, but it might be the logical replacement for a Europa Orbiter that cannot be afforded.


The only thing that would concern me here is that the bean-counters would use such a mission proposal as ammo against future Flagships and resurrect 'do more with less'...and we all remember the ugliness that followed from that.

Unpalatable as it sounds, the community needs to blend in some marketing pizzazz along with its proper focus on science objectives; this means that new missions probably have to accomplish at least one unmistakably new thing, ideally with a high coolness factor. How about adding the "bowling ball" Europa lander to JamesFox's proposal? The idea would be to do a Cassini/Huygens-style drop-and-listen flyby, and get a couple of hours of invaluable ground-truth data along with some nice pics...

Posted by: BruceMoomaw Mar 22 2006, 12:06 AM

It would take a LOT bigger retrorocket.

By the way, I've just gotten a new E-mail from Paul Lucey in response to my account to him of how the Europa penetrator idea was greeted at the Europa meeting. Despite my own rapidly growing doubts about the idea, HE still thinks it's workable, but expresses his pleasure that a piggyback lander of ANY sort is being considered. (Assuming, of course, that Europa Orbiter ever flies at all.)

Posted by: JRehling Mar 22 2006, 12:12 AM

QUOTE (BruceMoomaw @ Mar 21 2006, 04:06 PM) *
It would take a LOT bigger retrorocket.


A nice resource for this board, and something that ought to be derivable in a one-time shot, would be a list of delta-vs, like the mileage chart in the road atlas. Earth would usually be the From (!), but there are many parameters for the To (given a world, there is flyby, elliptical orbit, circular low orbit, soft lander...).

Now, who will generate that table?

wink.gif

Posted by: BruceMoomaw Mar 22 2006, 12:16 AM

QUOTE (JRehling @ Mar 21 2006, 10:54 PM) *
Imagine a one-shot mission that flies on the cheap, wakes up just to image Iapetus's most intriguing terrain that Cassini doesn't get around to (this could also happen on the out-leg), samples Titan's upper atmosphere, images the Tiger Stripes up-close while sampling Enceladus's plumes, and returning the two samples to Earth. The proponents of whatever mission this was competing with would have to get a little sweat on their foreheads.


Don't overdo it, as Hubie told Bertie. That would require incredibly fancy piloting plus a hell of a lot of luck -- even if you cut out Iapetus and just stick with adding Titan. It would be much more practical -- especially for an NF-cost mission -- just to sample Enceladus and (maybe) the ring particles of Saturn. (It might also be possible -- as James Oberg suggests -- for the craft, during its Jupiter flyby, to set up a sampling flyby of the particles in Io's plumes, or maybe of the dust in the outer part of the Jovian ring. If you can't time it just right to fly by Io after all, you still have a major mission.) As for Iapetus: much more cost-effective to just set up one or two more Iapetus flybys during Cassini's extended mission.

By the way, Freeman Dyson was pushing just the same idea (in "The Atlantic", of all places) about 7 years ago for Europa: why land there when we can just collect the material thrown up into Jovian orbit by its geysers and check that for freeze-dried biological evidence? But he failed to consider the fact that Jupiter's radiation would almost instantly scramble biological organic compounds beyond recognition -- and now we also know that Europa's geysers, if any, have apparently shut down during this particular geological era of its life.

Posted by: mcaplinger Mar 22 2006, 12:21 AM

QUOTE (BruceMoomaw @ Mar 21 2006, 02:03 PM) *
the thought that JPL's (multiple) spokesmen might be deliberately lying through their teeth...

Of course they weren't lying through their teeth, Bruce, the world is not so black and white as you seem to think. But they were, I suspect, being overly optimistic about what the technology development groups were telling them. The same thing happened in the last EO project: the AO claimed that there was all this wonderful "X2000" radhard technology available, and as the proposal process went on, all of it proved to be vaporware. After that experience, I'd need more than a JPL scientist's claim that it was really ready for flight. As just one example, what non-volatile memory technology are they claiming is megarad-hard? Current flash memory cannot survive more than a few tens of Krads, and MRAM is neither dense enough or flight-proven that I know of.

Posted by: BruceMoomaw Mar 22 2006, 12:31 AM

Regarding other ideas: two of the second-tier NF missions proposed by the Decadal Survey were an Io Observer (a Jupiter orbiter to make repeated Io flybys), and a Ganymede Observer (ditto for that world). It doesn't take much imagination to envision using one copy of the same type of craft -- with few design changes -- for all four Galileans, for a lower-cost and higher-data replay of Galileo. The main problem might be that you very much want an Io Observer to have a polar rather than equatorial orbit to minimize its radiation dose, which minimizes your ability to do a gravity-assist tour of the other moons.

As for Titan: the cheaper version of the Titan Organics Explorer -- the wind-blown hot-air balloon that would make repeated landings to sample the surface -- was projected at the COMPLEX meeting to cost about a billion dollars (although this would probably turn out to be about as accurate as NASA's other cost estimates). It would have kept itself within that cost limit largely by simply skipping any accompanying Titan orbiter, and communicating directly with Earth instead. If so, then -- IF Cassini can locate a spot on Titan that seems likely to have water volcanism, and thus water-processed organics -- it might be possible, within the NF budget, to drop off a stationary lander onto that one spot, do the same analyses planned for TOE, and have it radio its data directly to Earth.

Alternatively, it might be possible within the NF budget to drop off, by itself, a wind-blown balloon that would never land, but would just blow around Titan mapping its surface in far more detail than any orbiter can do. (While the spectral windows for sunlight piercing Titan's atmosphere would seriously limit the ability of such a low-altitude permanent balloon to map the surface composition of Titan itself with near-IR, could it use a cluster of small lasers at different frequencies to illuminate the surface and allow such a near-IR spectrometer on the balloon to look for especially interesting spectral lines?)

All this, to put it mildly, is uncertain within the NF budget; but then we ARE just trolling for possibilities right now. And NASA has already announced that it will include as many as 6-10 overall Solar System mission concepts within its next New Frontiers AO in 2008.

Posted by: Bjorn Jonsson Mar 22 2006, 12:39 AM

QUOTE (nprev @ Mar 21 2006, 11:33 PM) *
QUOTE (JamesFox @ Mar 21 2006, 03:17 PM) *

What I was thinking of myself, is pretty much a New-Frontiers class moden mini-version of Galileo: a smallish Jovian orbiter with one RTG or solar panels, designed to study the Galilean moons via sucessive flybys. With the faliure of Galileo's HGA, even a little orbiter with modern instruments could easily outstrip Galileo in the volume and quality of the data returned. It might lack charisma, but it might be the logical replacement for a Europa Orbiter that cannot be afforded.

The only thing that would concern me here is that the bean-counters would use such a mission proposal as ammo against future Flagships and resurrect 'do more with less'...and we all remember the ugliness that followed from that.

This all depends on how likely outer planets flagship mission are to get approved in the not-too-distant future. Having started following solar system exploration in the 1980s I'm getting worried that no such flagship mission is likely to get approved as a 'new start' before 2020 (if ever).

Posted by: JRehling Mar 22 2006, 01:29 AM

QUOTE (BruceMoomaw @ Mar 21 2006, 04:16 PM) *
As for Iapetus: much more cost-effective to just set up one or two more Iapetus flybys during Cassini's extended mission.


If you can view longitudes that aren't the same ones we've seen over and over.

The problem is the orbit has a node, and the node stays the same, and it keeps visiting Iapetus at one of two orbital positions. To get the new science, you need not only to have the orbit pop back out to Iapetus distance, you also need to alter the node. This is compounded in difficulty because Iapetus has an inclined orbit, so if you want to avoid passing way above/below Iapetus, you need to find an orbit that is inclined enough to visit Iapetus and still get back to Titan (ie, be back in the orbital plane when Cassini is at Titan orbital radius). This isn't trivial.

Posted by: tedstryk Mar 22 2006, 03:22 AM

I'll admit that I am a big fan of the Galileo-2 style NF idea. What would really be cool is to do it with two craft, one that primarily deals with the outer three moons in an equatorial orbit, and one that primarily deals with Io in a polar orbit. But this will happen when devils ice skate.

Part of the bias is that, frankly, while I find Europa interesting, I don't find it any more interesting than Io and Ganymede. I think selling Europa by assuming that the idea of life in its ocean will attract interest is a dangerous game, because it rests on a long shot. If NASA continues to sell that line, and we eventually get down to that ocean to find it as dead as a door nail, NASA will have egg in its face that it may never be able to clean off.

Posted by: BruceMoomaw Mar 22 2006, 04:17 AM

One can conceive a craft in polar Jupiter orbit, with an extremely low periapsis that "threads the needle" of the doughnut-shaped zone of highest-intensity Jovian radiation (like Juno), and which initially has an apoapsis allowing it to make repeated flybys of Callisto before it fires its engine again to lower its apoapsis again for repeated flybys of Ganymede, and so on for flybys of Europa and finally of Io. This would not, after all, require any more fuel total than a craft that initially brakes itself into such an orbit for Io intercepts. The question -- which I can't even guess at -- is how much freedom this would give us for flying by different portions of the moons' surfaces, as compared to an equatorial-plane Jupiter orbiter.

I've been thinking more about the question: could such a Jupiter orbiter that makes repeated Europa flybys serve, after all, as an adequate substitute for Europa Orbiter?

Maybe.

One of the main organizers of the Europa Focus Group meeting asked the sum total of assembled scientists in the room (and there were a lot) whether anyone thought this kind of intensive study of Europa would be justified if the place didn't have biological significance. Dead silence followed. Europa Orbiter is intended strictly as necessary advance preparation for the next mission, the big Europa Astrobiology Lander that would touch down and analyze the upper layers of the ice (perhaps down as deep as 100 meters or so, if it does its sampling with a short-range cryobot) for evidence of life.

Now, EO officially has two main purposes. One is to nail down once and for all absolute proof that Europa DOES have an ocean. A Jupiter orbiter cannot use a laser altimeter to make adequately sensitive measurements of the degree of tidal flexing of Europa's crust to answer that question -- but the induced magnetic field measurements of Galileo have almost totally nailed it down already. In fact, William McKinnon reported that the latest analyses of Galileo's data have flatly ruled out the slightest possibility that the field it detected was produced by any conductive material that wasn't in a layer very close to the surface. Indeed, the thickness of the layer indicated by the latest analysis of it is so thin -- maybe only 20 km thick -- that even seawater isn't conductive enough to generate the field unless a large amount of sulfates are dissolved in the water (which, of course, is precisely what the near-IR spectra of Europa's ice also indicate). A flyby craft with a magnetometer, making far more flybys of Europa targeted for this purpose than Galileo did, would surely get enough more induced-field measurements to nail this down even more solidly. We'd need repeated simultaneous data from two magnetometers in different places to be able to use it to gauge the thicknesses of the ice layer and the ocean itself, but that data is not in itself necessary to plan the Astrobiology Lander (which I will hereafter call EAL).

The other main purpose of EO is to find good landing sites for EAL. It would obviously be of huge assistance in that -- but if we're really strapped for money, we need to ask whether EO is absolutely necessary to pick out a good first landing site for EAL. Torrance Johnson, at the last astrobiology conference at Ames Research Center, said flatly that he thinks we can pick out a satisfactory first one just from the limited data we've already gotten from Galileo. That seems highly doubtful to me -- but a follow-up Jupiter orbiter with a properly working high-speed data link could do a lot of additional reconnaissance for such sites during its flybys of Europa, quite possibly enough for us to find a pretty satisfactory place even without full-scale coverage of Europa from an EO. It would unquestionably carry a high-resolution camera, a thermal mapper to look for any recent sites of vented water, and a near-IR spectrometer to map the makeup and concentration of materials that had oozed up to the upper ice from the ocean underneath -- and the likely spot for EAL will be one where that concentration is high, and where the lack of surface cratering and regolith suggests that the surface material has been exposed to Jupiter's radiation for only a relatively short time. It could map a lot of Europa just with those instruments.

There seems to be serious question as to whether or not such a flyby craft could get meaningful data from ice-penetrating radar -- even for just a few short strips of Europa's surface. But, again, while IPR is obviously extremely important for general studies of Europa, we have to ask whether it is absolutely necessary to pick out the best landing site for EAL, given the data we'll get from those other instruments. The main relevance of IPR for that particular purpose would be to try to locate pockets or fissures of liquid water very close to the surface -- within just 100 or 200 meters. But it might be possible to at least detect -- and map the horizontal extent of -- pockets of liquid water that close to the surface in a lot of places with a relatively insensitive, shallow ice-penetrating radar of the sort that a flyby craft MIGHT be able to use, even if it didn't measure the actual depth below the surface of such pockets beyond telling us that they were near-surface. And such a less ambitious and sensitive radar instrument used from a flyby craft might also be able to measure both fine-scale surface roughness -- very important data in picking out the EAL landing site -- and also the content of other material (rock dust and salts) in the ice, which could be very important in designing any sampling cryobot carried on EAL.

So, if we're as seriously strapped for cash as we now seem to be, it might -- repeat, might -- be feasible to replace EO with such a cheaper and simpler "Galileo 2" Jupiter orbiter that could survey not only Europa but also Ganymede, Callisto and maybe Io, as all the advance preparation we'd need to then jump straight to the Astrobiology Lander as the next Europa mission.

Posted by: BruceMoomaw Mar 22 2006, 04:27 AM

Come to think of it, the kind of radar instrument I'm talking about for a repeated Europa flyby is actually very similar to the SAR on Cassini -- its purpose would be not mapping depth, but mapping the horizontal extent of features such as near-surface water pockets. In that respect, it would resemble the SAR that Tom Campbell proposed for a Mars Scout orbiter (and will now propose again, under the name "Eagle"), which would work at a wavelength allowing it to punch through just the upper surface soil layer of Mars to make SAR maps of the bedrock features underneath. It would also resemble the "Mini-SAR" that Bruce Murray will put on both the upcoming US and Indian lunar orbiters: a relatively lightweight instrument to map the horizontal extent of lunar polar ice deposits. It would presumably work on 2 or 3 frequencies, one to map Europa's actual surface roughness and radar reflectivity, and another to probe some distance beneath the surface for near-surface water pockets. But, viewed this way, we could certainly design one that would work from a flyby craft, and might be able to cover quite large areas.

Posted by: edstrick Mar 22 2006, 07:36 AM

To a very real extent, a landing on almost any of the dark reddish "boil-up" spots that have punched up through the crust would do the trick scientifically. Especially one of the ones where the surface seems to have been ice-blocks floating randomly in iceberg slushies.

Posted by: BruceMoomaw Mar 22 2006, 08:43 PM

They want regions that are both dark-colored and sufficiently devoid of impact craters to indicate that they're relatively recent -- and one feature which has attracted interest from the start is Castalia Macula, that very dark and quite smooth spot observed by Galileo, which looks like a frozen, relatively recent water flow. (I need to go over my notes on the Focus Group Meeting again to see what else was said about landing sites.)

Posted by: BruceMoomaw Mar 26 2006, 12:51 PM

One more interesting LPSC abstract describes a revised version of CRISM which could be used to make very detailed near-IR compositional maps of Europa (or, of course, other worlds):
http://www.lpi.usra.edu/meetings/lpsc2006/pdf/1821.pdf

Posted by: GravityWaves Mar 26 2006, 07:22 PM

QUOTE (mcaplinger @ Mar 15 2006, 02:50 PM) *
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.


Yes, it is

This is what is needed

1Europa/Jovian exploration
2Gravity projects like the LISA missions
3Exoplanet missions
4Precursor projects for Manned Mars flight

Although numbers 1-4 have been cut badly in the latest NASA budget, the rockets for return to the Moon/Mars can be used to launch TPF or a Europa lander.


The Euros are also thinking there may be life on Europa, and ESA have a number of ideas to Explore this world. Here are some bits of info on ESA's ideas.
http://news.bbc.co.uk/2/hi/science/nature/4347571.stm
http://sci.esa.int/science-e/www/object/index.cfm?fobjectid=35982

Posted by: BruceMoomaw Mar 27 2006, 06:37 AM

The very good March 17 "Science" article on space science's financial quandary ( http://www.lpi.usra.edu/opag/science_cuts.pdf ) says that the LISA space gravity mission will now have to face off against NASA's other big astrophysical cosmological missions for funding -- there simply is not enough to fund two or more of them simultaneously:

"Rising costs and flat budgets also will force NASA to compete several new astrophysics flights. Constellation X—a group of four orbiting telescopes that will image the x-ray universe— will face off against the Laser Interferometer Space Antenna, designed to detect gravitational waves, and a Joint Dark Energy Mission with the Energy Department. The winner will get a green light to start work in earnest in 2009 or 2010 for a launch later in the next decade. The other two will have to wait their turn."

Also note: "The Space Interferometry Mission, another planet-hunting mission, won’t be orbited until 2015 or 2016, and its cost has grown to $4 billion." Jeez. This definitely supports Fran Bagenal's statement ( http://www.lpi.usra.edu/opag/07_budget_bagenal.pdf ) that it's inaccurate to say that space science's only problem is that growing Shuttle/Station expenses are bleeding off its funds (although that's obviously part of it): "I feel on thin ice asking for additional funds -- new money -- when a second glance at the NASA budget reveals the current rhino in the room to be the fact that we have lost control of mission cost growth."

So "Gravity Waves' " wish list has no chance of being funded in toto -- or close to it -- and an excellent case can be made that it SHOULDN'T be. To twist Bette Davis a bit: Let's not ask for the Moon when we don't even have the stars yet.

Posted by: The Messenger Mar 27 2006, 04:47 PM

QUOTE (BruceMoomaw @ Mar 26 2006, 11:37 PM) *
The very good March 17 "Science" article on space science's financial quandary ( http://www.lpi.usra.edu/opag/science_cuts.pdf ) says that the LISA space gravity mission will now have to face off against NASA's other big astrophysical cosmological missions for funding -- there simply is not enough to fund two or more of them simultaneously:

...So "Gravity Waves' " wish list has no chance of being funded in toto -- or close to it -- and an excellent case can be made that it SHOULDN'T be. To twist Bette Davis a bit: Let's not ask for the Moon when we don't even have the stars yet.

The importance of the Lisa mission is difficult to judge: We are still waiting for positive results from LIGO, and any results from the Gravity B probe. Although LIGO is well into the S5 science run (which are expected to yield something), the data reduction takes months.

If the LIGO telescope is highly successful, does it make LISA more or less important? If LIGO fails to detect anything - that would seem to make LISA more urgent. However - and this may be what Bruce was eluding to, there are severe technical challenges in building an extremely sensitive space based interferometer - and without an army of these little robots we all wish existed, to fine tuning and tweaking this fringe technology, LISA becomes a iffy gamble at best.

I vote to concentrate on Europa. I think it is essential that the mission include multiple seismic sensing capability, as well as Raman X-ray and GCMS capability. The last thing we need is another mystery surface with 'no known equivalent'. Proper instrumentation, based upon the premise we do not know rather than assumptions that we do.

Posted by: The Messenger Apr 11 2006, 05:07 PM

http://www.space.com/news/060407_nss_nasa.html

QUOTE (space.com)
Griffin said that budgetary constraints forced NASA to call a halt to planning for a Europa mission. “But sometimes when you close one door, another opens,” he added, making note of the much lower radiation environment of Saturn’s moon, Enceladus. That moon was recently found to have possible liquid water reservoirs erupting in Yellowstone-like geyser fashion.


Enceladus may be an easier target to explore, Griffin said. “We’ll see.”

Posted by: ljk4-1 Apr 11 2006, 05:45 PM

I know Griffin is an engineer, but how much astronomical science training has he had?

How much does/can he really appreciate exploring other worlds for the sake of
knowledge?

I know Griffin has a mandate from his bosses (Bush and Cheney) to get humans
on the Moon and Mars (and Beyond they like to add, cause it doesn't cost anything
just to say it), but what happens in 2009 and will space science even be happening
by then?

Posted by: Spacely Apr 11 2006, 09:24 PM

QUOTE (ljk4-1 @ Apr 11 2006, 10:45 AM) *
I know Griffin is an engineer, but how much astronomical science training has he had?

How much does/can he really appreciate exploring other worlds for the sake of
knowledge?

I know Griffin has a mandate from his bosses (Bush and Cheney) to get humans
on the Moon and Mars (and Beyond they like to add, cause it doesn't cost anything
just to say it), but what happens in 2009 and will space science even be happening
by then?


Well, I'm fairly certain planetary space science isn't going anywhere, even if it's reduced. Post-2009 we can still expect JUNO, Mars scout 2011/2013, RLEP-2, and whatever new Discovery Mission (or two) they greenlight in the next 18 months. JWST is still a go, too. If they manage all those things and a Crew Launch Vehicle and CEV by 2013, I'll be happy. It's a much better haul than what we got between 1975 and 1985.

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