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Posted by: Redstone Sep 15 2005, 07:12 PM

There has been lots of discussion of a mission to Europa in the http://www.unmannedspaceflight.com/index.php?showtopic=1039. I thought that since a Europa mission seems to be once again becoming a possibility, it deserved its own thread for news, updates and discussion. I thought I'd kick things off with a summary of past efforts on a Europa mission, and on where things stand now. If I make a mistake, please correct me!

In the course of its prime and extended missions, Galileo found http://www.spacedaily.com/news/life-00p1.html under the icy surface of the planet. Planning began on a Europa Orbiter mission, with a projected arrival date of 2008, to confirm the presence of the ocean, characterize the thickness of the icy crust and identify places for a future landing. One thing to note about these earlier plans: they included a direct trajectory to Jupiter, presumably to minimize mission duration and qualms about RTGs re-entering Earth atmosphere after some (highly unlikely) targeting mishap. But NASA lacked a nice category of missions to place the Europa Orbiter in. Eventually it got lumped together with Pluto Express and Solar Probe in a Outer Solar System program labelled "Fire and Ice", a term which also got applied to the Galileo Europa Mission extension. Without a solid program to support it, (like Mars Exploration, Great Observatories, or Discovery) the mission looked like an orphan.

As Bruce Moomaw has well documented, attempts to kill off the Pluto mission led to a tug of war between NASA, the planetary scientists and the public, resulting in Congressional directives to NASA. Pluto Express became the Pluto/Kuiper Belt Explorer and then New Horizons and New Frontiers 1. (New Frontiers 2 is of course Juno.) But the cost for the Europa mission continued to rise, and the launch date recede, as the difficulty of radiation shielding and the large delta-v requirements hit home, and the mission's public profile fell. The launch date moved to 2010 and the costs moved over a $1b. Then along came Sean O'Keefe and JIMO, a justification for the Prometheus program through developing nuclear electric propulsion, not with RTGs, but with an in-space fission reactor. Launch got moved to http://www.astrobio.net/news/modules.php?op=modload&name=News&file=article&sid=713, http://www.spacedaily.com/news/outerplanets-03k.html, while the cost went even further http://www.space.com/businesstechnology/050406_prometheus_techwed.html.

With the arrival of Mike Griffin, JIMO was cancelled. As Griffin said to Congress, "It was not a mission, in my judgment, that was well-formed." But interest in a Europa mission remained and remains strong. In 2003 the National Academy of Science's http://books.nap.edu/catalog/10432.html flatly stated that a Europa Orbiter was the top priority for the next Large scale (aka Flagship) mission. (See page 196 of the report.) NASA's current http://www.hq.nasa.gov/office/apio/pdf/solar/solar_roadmap.pdf reaffirmed a Europa orbiter as the next flagship mission. The question as always is money. As Administrator Griffin said, "The Science Mission directorate wants to do a Europa mission, the National Academy of Sciences wants to do a Europa mission, I want to do a Europa mission. When we can afford it in the budget, we'll do it."

Evidence of that support beyond rhetoric and reports trickled out with a letter from Andy Danzler, NASA's Solar System chief, to the Outer Planets Assessment Group (OPAG). He reported that he had "funded a team to take a quick look at the boundary conditions of a mission to Europa, that is, how much power, mass, travel time, etc. for various realistic scenarios. For planning purposes, this group is looking at launch dates in the 2012-2015 range, although the later dates are more likely in terms of funding." For funding details however, we have to wait for the FY 2007 budget.

OK, now the good stuff.

The http://www.space.com/scienceastronomy/050614_outer_planets.html included http://www.lpi.usra.edu/opag/jun_05_meeting/presentations/EGE_Mission_Study.pdf for the mission. A kind of first draft which establishes a baseline which can be tweaked and modified to extract the best science return.

There are many things to like about this draft design:
* The mission is now permitted to use Earth flybys, and uses a proven trajectory, the same as used by Galileo (Venus-Earth-Earth Gravity Assist). This allows a BIG increase in the available mass.
* The orbiter uses RTGs, but not super advanced ones that require further years of development.
* The orbiter is similar to Cassini in appearance, with 2 engines, a cylindrical tank structure, RTGs at the base, the magetometer boom at the top, and space for a lander bolted to side. The similarities may make it easier to convince Congress that this is something NASA knows how to do. The most obvious configuration change is with science payload and HGA having switched places, and the addition of a radar array. And there looks like a camera the size of MRO's HiRISE!
* The mission is definitely Flagship in scope with a launch mass of over 7000 kg on a heavy lift launch vehicle. For comparison Cassini was 5712 kg at launch on a Titan IV, and Galileo was 2223 kg when launched using the Shuttle and an Inertial Upper Stage.
* There is a good opportunity for ESA participation with the lander and science instruments. NASA/ESA co-operation is on the agenda for the next OPAG meeting.
* The mission does not assume big upgrades to the Deep Space Network. If the http://dsnarray.jpl.nasa.gov/ does come along, that's just gravy.
* Despite the Europa focus, the mission appears to give at least part of a Galilleo II style tour with multiple flybys of the outer Galileans over 18 months. Only Io will have to wait.

The OPAG Europa working group is also expected to present further work at the next meeting in October. More details will emerge then. I think there is room for cautious optimism on this mission. While we won't be seeing a mission launch for at least another 7 years, the combined weight of the planetary science community does tend to get it's way in the long run. I think the momentum is finally starting to build.

Posted by: BruceMoomaw Sep 15 2005, 08:39 PM

Very nice work. (My saying this, by the way, has no connection whatsoever with your praising my work on the Great Pluto Probe War...) Absolutely the only error I can detect -- and I've long been obsessed with Europa exploration -- is that the original design for Europa Orbiter DID have a big radar array that in fact looked very much like this new one; it was just located at a different place on the craft.

And, yep, they seem determined now to add a very big HiRISE-type camera, in addition to the much smaller one they planned from the start. Not only are high-res shots of Europa important for understanding its surface processes; they're crucial for figuring out how to safely land spacecraft on what looks like a VERY rugged surface. While I'd love to see a small lander (if properly designed) added to this mission, however -- as would Jack Farmer -- it is very much up in the air whether they'll have the money to do so. (I'm currently planning a future article arguing that the best possible design by far for a small lander on this mission would be a penetrator rather than a surface lander.)

Posted by: Decepticon Sep 15 2005, 09:20 PM

I'm all for the Penetrator.

Posted by: Bob Shaw Sep 15 2005, 09:54 PM

Yeah. We could use the spare ones the Japanese have...

Posted by: infocat13 Sep 15 2005, 11:07 PM

45% to 50% of the cost of the Europa orbiter mission is the cost of mission design and test.I would build 4 more space craft of identical design except for the mass set aside for the lander/probe.this mass would be used by a payload best suited for the target planet. targets? saturn(a cassini follow on) uranus and neptune. the 4th spacecraft would be insurence or a mission of oppertunity.

Posted by: tedstryk Sep 16 2005, 12:18 AM

It might be neat to buffer one up and put a more appropriate instrument sweet on it, and send it on a tour like that of Galileo's later years (in other words, flying by Io repeatedly and occasionally other moons). With a Hirise likecamera, it could study Io's temporal activity, with closeup coverage every few weeks.

Posted by: Decepticon Sep 16 2005, 01:27 AM

Europa/Io complete mapping is a must.


What a disappointment with mapping from Galileo. Even with the extended mission Europa is still poorly mapped.

Posted by: JRehling Sep 16 2005, 02:47 AM

The thing that worries me is that we are, by necessity, playing a game of Twenty Questions with Europa, and a big, battlestar-galactica craft asks a lot of questions at once, meaning that some of them may be mis-asked. (Like the fluid-probing instruments on Huygens.)

A big camera plus a possible lander could serve purposes, for sure, and if they came for free, who could complain? But look at how many missions we're using to pursue Mars exploration... Given that Europa is also going to take a lot of missions to crack (surely spread over a much longer span of time), a smaller scope might be called for.

Note that with a powerful camera, not much of the surface gets mapped: MOC on MGS will end up mapping only a few percent of Mars's surface (it was have been about 1.5%, IIRC, in the nominal mission). The kicker is, a Europa Orbiter won't live for a decade like MGS, but a month, so *very* little of Europa's surface will benefit from the camera's work. Granted, an attempt to image representative sites (both typical and the odd, atypical feature) should return a weighty fraction of the scientific knowledge that a comprehensive high-res mapping would, but the value of the camera still has to be weighed against that. I suppose the idea would be to produce *final* imaging of potential lander sites, and you have to do that sooner or later, so why not now? Well, the answer might come once the other instruments have had a look.

For a lander, that goes in spades. If we find something out from the hi-res camera, that could really affect lander design.

I think it'd be wiser to launch a probe with radar, a good-not-great camera, no lander, and have a quicker turnaround til the next mission. Europa's not going anywhere. Let's be methodical instead of extravagant.

Posted by: tedstryk Sep 16 2005, 02:51 AM

Well, actually, in its low resolution channel, MOC has mapped the planet many times over at resolution of a few hundred meters. If the big camera comes with something like CTX, it could be quite useful. I also think that we are in a bit of a better positon with regard to a priori knowledge at Europa than at Titan. With a lander however, that is not the case. I don't think we know about the surface at a fine scale well enough for good site selection, although a relatively simple penetrometer wouldn't hurt - I just think it is early.

Posted by: Redstone Sep 16 2005, 04:25 AM

I think you have to balance the size and capability of the spacecraft against the permissible frequency of visits. Because of Europa's distance, and the large delta-v required to go into orbit, a sequential program like that for Mars is not going to be feasible. So there is more demand for the number of question-answer cycles to be kept to a minimum, even if that means more capable, and hence more expensive missions.

When it comes to any form of lander, I think anything complex will send mission risk and cost too high. But penetrometers may be vulnerable to being axed once the squeeze begins for spacecraft resources and funding, even if we are looking at 7 tonnes for the mission. The Decadal Survey *did* identify a Europa orbiter and lander as separate missions, after all. If the lander is an international contribution, that would make it more secure.

The HiRISE style camera is interesting. Certainly the 30 day prime mission is way too short a time to return the amount of data involved in mapping at that kind of resolution. Since the mission will have a wide angle camera for the global mapping, the question would be where to aim the big mirror. One aspect of the mission that would help is the many flybys and steady final approach to Europa before orbit insertion, which would give lots of opportunities for preliminary surveys. Also, if the mission carried a lot of onboard memory, then once in orbit thumnails could be sent, and then selected detail returned. But at that point the mission team would have to make up its mind *fast* (i.e. on a daily basis) on what was to come back in high resolution.

Posted by: edstrick Sep 16 2005, 07:30 AM

With a HiRISE style camera, you can do an enormous amount of high quality "raster" style mapping of moons from a distance. Either with a framing camera or a pushbroom sensor (I'd go with framing cause of low light levels), you couild build up low-distortion gigapixel mapping mosaics before the spacecraft moves a lot or the moon rotates a lot.

Somebody do the math and tell me for Galileo-type orbits, what resolution you get 6, 12, 24 and 48 hours from a flyby of the 3 ice moons, and what resolution <km/pixel> you get on Io.

Posted by: Marcel Sep 16 2005, 11:05 AM

Would a soft lander be possible given the allocated space (and mass) for it on the craft ? I assume there's no real atmosphere to parachute into, so i'm afraid the answer is NO.

Posted by: Marcel Sep 16 2005, 11:20 AM

http://www2.jpl.nasa.gov/galileo/europa/hst.html

"Europa's oxygen atmosphere is so tenuous that its surface pressure is barely one hundred billionth that of the Earth,"

I guess my dream of having a stereo camera with 360 PAN capability on Europa shatters here. A soft lander seems impossible for now......

Posted by: antoniseb Sep 16 2005, 12:25 PM

Even a simple very small lander (a kilogram of instruments) would be useful for learning some things that we'll need to know for a more complex lander/rover. The Hi resolution camera won't be able to resolve things better than a few meters, and will be unable to actually test the surface composition.

Posted by: Marcel Sep 16 2005, 12:41 PM

But soft landing without an atmosphere isn't possible. At least not for the allocated mass of the lander.

Posted by: Decepticon Sep 16 2005, 12:47 PM

I was thinking more in the lines of a Melt its way threw type probe.


Or how about this!

Posted by: Marcel Sep 16 2005, 12:55 PM

What the h... is that ?

Posted by: ljk4-1 Sep 16 2005, 01:12 PM

Ever seen the sequel to 2001: A Space Odyssey?



It actually looks both plausible and Soviet.

Posted by: Bob Shaw Sep 16 2005, 01:30 PM

Marcel:

Let's think outside the box...

...Ranger-A plus airbags?

Bob Shaw

Posted by: Marcel Sep 16 2005, 01:37 PM

I suppose that IF we could make airbags that strong, it would easily thump! back into space far beyond the escape velocity of 2,2 km/sec.....it would buy us about a nanosecond on the surface

Posted by: Decepticon Sep 16 2005, 01:41 PM

I'm 30 now, I hope that before I kick the bucket that I'll know for sure if there is a Subsurface ocean or not.

Life or No life.

Just the fact that a ocean other than our own is out is very cool.

A subsurface/orbiter probe should be Top Priority. *Ducks at Tomato's*

Posted by: antoniseb Sep 16 2005, 04:15 PM

If the orbiter released a craft from low orbit and the craft had a small rocket to de-orbit and layers airbags intended to pop on impact you might sufficiently decelerate a fairly hard set of instruments (perhaps 60 to 100 g's).

I'll have to do a few quick calculations to see if this is reasonable. The big doubt item is whether anything useful can be put in a small enough lander.

Posted by: ljk4-1 Sep 16 2005, 04:17 PM

They had airbags on Luna 9.

Posted by: JRehling Sep 16 2005, 04:37 PM

An alternative is to be resigned to the fact that Europa exploration is going to take a lot longer than Mars exploration. The trade-off, simply put, is: Do we want to get the most bang for our buck but have it take more time to fly all the missions we want, or do we want to get the science sooner and risk some missions/instruments that end up missing the point due to some yet-unknown characteristic(s) of Europa?

Don't kick me out of the enthusiast club, but I can't fabricate a case for urgency here. If it takes 8 billion-dollar missions to reach a certain level of understanding, vs a quartet of 3-billion-dollar missions completed in half the time, how do you explain (to the public??) that getting the answers sooner is worth the extra $4 billion? Assuming a fixed budget for exploration, this also means the rest of the solar system gets gyped out of many missions. There is opportunity cost.



I think a smash-and-grab mission that uses an impactor to blast some ice up to a collector that is on a free-return trajectory to Earth has to be considered.

As I see it, the lander concept comes down to two main investigations: What is the composition of the non-H2O stuff? Is there a seismic/thermal/magnetic indication of the structure/activity of the crust and subcrust?

An orbiter can start to speak to the magnetic and probably thermal (by scanning the nightside and eclipsed-dayside in IR) issues. Smash-and-grab would give us a point sample of composition.

I think a very strong candidate plan for the first two missions would be an orbiter that performs detailed surfacing mapping, including scrutiny of whether or not the non-ice component is the same compositionally everywhere. This mission would screen for the best possible locations for any future surface mission, whether it be smash-and-grab, a Pathfinder-style lander, or a penetrator-lander. It is certainly risky to launch a lander of any style without having that basic reconnaisance completed.

The case for the second mission being a lander seems elusive to me. The magnetic and thermal questions will be addressed in part by the orbiter (of course, note: the conditional nature of that statement is already evidence that the second mission should be designed around the results of the first). A smash-and-grab mission would not provide the seismic data of a lander, but would provide infinitely better analysis, in earthly labs, of surface samples -- for far less delta-v.

The combo strategy I have mentioned before for the first landed mission would be to have a lander with seismic capabilities touch down (or penetrate) first, then have an impactor (with its own camera, of course) strike the surface nearby shortly thereafter, providing a known seismic event that would probe the crust fantastically. That same impactor could be the one spraying particles up to the catcher's mitt on the free return trajectory. In all, three elements involving the surface, designed according to the results of the orbiter mission, with a broad wealth of returned data: seismic, magnetic, and thermal data from the landed probe at one location, closeup imagery of a second location, precise seismic data which would give excellent data on one location in the crust, and samples for earthly labs!

Seen this way, the great upside is not to link Mission 1 and Mission 2 to the same launch, but Mission 2 and Mission 3.



I agree that sophisticated regimes for selecting imagery returns are called for. I don't see why such a mission could not have truly massive memory (cmon, that's light), and the ground crew would have the entire duration of the mission to request imagery for downlink -- imagery taken the first day should still be available for downlink on the last day. Store everything, or at least a heck of a lot. It's a nice thought that the orbiter could have a great set of high resolution imaging in its memory, and the ground crew could peruse the low resolution map, and then request detailed observations in terms of a downlink, as opposed to in terms of a new, future observation.

Posted by: ljk4-1 Sep 16 2005, 04:54 PM

Such a mission was developed called Europa Ice Clipper. A 50-pound ball would be slammed into Europa by a flyby probe, which would fly through the debris cloud, grab some samples of Europa, and return them to Earth.

http://www.astrobiology.com/europa/ice.clipper.html

Posted by: BruceMoomaw Sep 17 2005, 07:53 AM

I've been thinking for some time about a modified version of Ice Clipper, in which the spacecraft would be based not on Stardust (with a small impactor) but on Deep Impact (with a much bigger Impactor kicking up a much larger amount of debris, and kicking up almost all of it from depths far below the radiation-modified upper layer). The Impactor's camera could also get extremely high-res final photos which could provide additional valuable information on small-scale surface ruggedness for the purposes of lander design.

I've even wondered if it might be advisable to launch such a mission BEFORE the Orbiter; a high-res camera and near-IR camera on the main craft, coupled to a very high-capacity and high-speed data recorder, could get high-resolution terrain and compositional data on quite a respectable part of Europa's surface just from a flyby (like the "Firebird" Io flyby once proposed as a Discovery mission). One possible motivation for such a mission flying first has disappeared, though: Janus Eluszkiewicz's argument that Europa's upper layers might be riddled with large cavities that would seriously interfere with the depth penetration of a radar sounder -- making it advisable to test the effectiveness of Europan radar sounding from a flyby first -- has come under very serious fire on the grounds that he simply assumed that such cavities could exist when the physical evidence is against it: http://www.lpi.usra.edu/meetings/lpsc2005/pdf/2346.pdf .

And the big problem with a smash-and-grab mission remains: given the very small amount of surface material that it would collect, could even supersensitive Earth-based labs properly inspect the sample for biological evidence? (Especially since it's quite possible that the heating the samples would inevitably undergo as they plowed through the aerogel collector layer would break down organic compounds.) if so, it might be preferable to initially analyze Europa's ice using in-situ instruments, even given their greatly reduced sensitivity and flexibility, simply because they could analyze much bigger amounts of material. JPL's own design study for an initial lightweight Europa soft lander ( http://www.lpi.usra.edu/opag/jun_05_meeting/presentations/EGE_Mission_Study.pdf ; http://www.lpi.usra.edu/opag/jun_05_meeting/presentations/EGE_Science_Instruments_Trace_OPAG.pdf ) calls for such an organic-isotopic analysis -- using a combined liquid chromatograph and mass spectrometer -- as one of the two top priority instruments for a Europa lander, the other being a seismometer for data on ice-layer total thickness. I myself would regard organic analysis as even more important.

The problem is collecting a big enough sample for such analysis on a small lander -- and collecting it from a fair depth, below the radiation-scrambled surface layer, using a lightweight sample-collection system. The JPL study (which focuses on a surface lander, just because that's the one design it was contracted to examine) expresses concern about this, but doesn't mention specific solutions. A penetrator would seem to be the logical solution. The "Polar Night" Discovery mission proposed to analyze lunar polar ices -- which could well end up as the second in the new series of US lunar exploration probes -- called for three penetrators, each weighing only 30 kg, surviving a crash into the surface at 75 meters/sec and burying themselves 1-2 meters deep ( http://www.nrl.navy.mil/techtransfer/exhibits/pdfs/Info%20Sheet%20pdfs/Space%20Info%20Sheets/PolarNight.pdf ; http://www.mae.usu.edu/faculty/tmosher/GeneratedItems/media/Mosher.pdf ). They would each carry a neutron spectrometer (not necessary for Europa) and a mass spectrometer, and impact tests in which these instruments were fired into a 2-meter layer of plywood and exposed to 1200 Gs (four times their planned load) showed them surviving just fine.

Again, though, if interesting compounds are seriously diluted in the Europan ice, the problem is acquiring enough of them to analyze -- which might require a heated probe to melt its way down through several dozen meters of ice and filter diluted compounds out of the resulting large amount of meltwater ( http://lasp.colorado.edu/icymoons/europaclass/Chyba_Phillips_EurAbode.pdf ). But such a probe would almost certainly be too big to carry as a piggyback on Europa Orbiter.

If a small penetrator COULD have a chance of analyzing enough material to be worthwhile, however, it would seem vastly preferable to a surface lander as a piggyback on Europa Orbiter in almost every way. It would easily dig below the radiation-modified surface layer (unlikely to be more than a meter or so deep); it would be much lighter than a surface lander; it could land on virtually any terrain, no matter how rugged; it would bury itself and thus provide its own shielding from Jupiter's radiation (which is otherwise a major problem for a moderately long-lived lander); and it would couple its seismometer to Europa far more rigidly than a surface lander. It would probably be unable to obtain post-landing terrain photos, but it could record descent photos during the last few seconds before impact and play them back later for almost equally good imaging data.

Posted by: BruceMoomaw Sep 17 2005, 07:57 AM

Stop press! While poking around on the Web for the above note, I've just found that Paul G. Lucey -- the Principal Investigator for "Polar Night" -- is also working on "Thunderbolt: In-Situ Detection of Biotic Compounds on Europa" ( http://www.higp.hawaii.edu/cgi-bin/higp/directory.cgi?func=disp&searchname=PaulG.Lucey ). This is surely a Europa penetrator, and I intend to talk to him about it immediately.

Posted by: deglr6328 Sep 17 2005, 07:36 PM

Not being familliar with Luna-9, I checked it out and.....did the engineers include something of an easter egg in http://en.wikipedia.org/wiki/Image:Luna_9_landing_capsule.jpgimage?

Posted by: Bob Shaw Sep 17 2005, 09:03 PM

I don't think so... ...there was a big insulating cover over the lander - is that what you're thinking of?

Posted by: vjkane2000 Sep 18 2005, 12:34 AM

Penetrators have been proposed for many missions, but they always suffer from the same problems: very limited room for sophisticated instruments (big difference between a spectrometer that can detect water and one that can unambiguously classify organic molecules) and the need for entry into the surface to be near vertical. At the same time, there are some nice features to penetrators for Europa: they did beneath the surface ice (good for sampling) and have a meter or two of ice shielding them from the radiation (good for a longer life). A potential issue: if the Europeans do the lander, I don't think they have much experience with penetrators, but could be quite wrong on this.

Posted by: Jeff7 Sep 18 2005, 02:38 AM

Someone mentioned an impactor - how about using a small stream of impactors to blast successive craters, and at the end of the stream would be the instrument-laden lander itself? It might still need to drill, but not nearly as much.

Posted by: BruceMoomaw Sep 18 2005, 07:56 AM

Uh-uh -- you'd need a huge weight in impactors to blast a hole of any significant depth, whereas you could achieve much greater penetration for tremendously less weight just by making the probe a melt probe (or giving the surface lander a longer drill). To say nothing of the gargantuan targeting difficulties...

Posted by: ljk4-1 Sep 18 2005, 02:35 PM

Back in 1998 I initiated a discussion list for landing a probe on Europa to explore its subsurface global ocean. Named Icepick, the discussion lasted until just a few months ago.

http://www.klx.com/europa/

You can read the discussions here. I think we hit on many if not most of the scenarios for making this mission plan a reality.

http://www.mail-archive.com/europa%40klx.com/

If someone wants to revive the Icepick list and get discussions going again, I would be most grateful. Jeff Foust ran the intial list and Web site.

Posted by: BruceMoomaw Sep 18 2005, 09:46 PM

Yep, that's the site where I got my start as a space commentator -- and where Simon first ran into me. Sad to see that it's finally disappeared. Maybe I should have hung around there, but I've been juggling several plates at one time for the last few years and just never got around to dropping back in. It starts to look as though the discussion site for Europa exploration may migrate over here.

Posted by: Redstone Sep 19 2005, 02:47 AM

Apologies if this has already been discussed, but on the OPAG site, there's http://dosxx.colorado.edu/%7Ebagenal/OPAG/ESSP_Report_Final2.pdf on Europa Surface Science options. It runs to 86 pages and covers radiation issues as well as landing methods. It was based on the JIMO as the mothership, but much of the discussion is still relevant, I think. I haven't had the chance to go through it in detail, but one point caught my eye: for 375 kg, you can soft land 167 kg on the surface using powered descent. For comparison, the Huygens probe had a mass of 320 kg.

Posted by: Jeff7 Sep 19 2005, 03:25 AM

Ok, a melt probe. RTG powered I assume? Just did a quick search.....one page says this of Cassini's RTG's:
"The alpha particles naturally heat the pellets to 572 degrees Fahrenheit (300 degrees Celsius)."
Not too bad at all, more than I expected actually. That'd definitely make a hole....though I'm just thinking now, it'd encase itself beneath the ice. The water above would likely refreeze fairly quickly, even with a toasty robot beneath it. So the little meltbot would be sealed under the ice rather quicly. What would it use for communication? A fiber optic line would be risky (might get tangled), and would add weight. And I don't know how well radio waves penetrate ice.

Posted by: hendric Sep 19 2005, 04:39 AM

A fiber optic cable is probably the best bet, using a floating transmitter/receiver at the end of the line to keep it above the meltwater until it refreezes. Radio would require repeaters to go through the ice, which is possible, but you'd have to power them somehow, and keep them from melting down (or up!) when they activate.

Posted by: BruceMoomaw Sep 19 2005, 09:04 AM

Jeff: I saw that OPAG report -- and the two more recent papers att the OPAG site that I mentioned previously elaborate on it somewhat.

Hendric: The idea of a fiber-optic line for communications -- originally the favored idea -- got the boot several years ago, both because of weight problems and becuase the slow but steady ductile sliding of Europa's ice layers would almost certainly snap it. The current plan is to have the probe carry a stack of tiny disk-shaped radio repeater packages powered by tiny RTGs, and release one every kilometer or so that it descends -- so that they're close enough to pick up each other's radio signals through the ice and thus chain-link the signal from the melt probe all the way to its surface carrier.

Posted by: BruceMoomaw Sep 19 2005, 09:05 AM

I should add that the heat from the extremely tiny RTG that each such package would require would not be nearly enough to melt the surounding ice and make it sink deeper.

Posted by: deglr6328 Sep 19 2005, 09:14 PM

Wouldn't it? Let's say you want a 10W transmitter. You will need at least, I don't know, ~15W total for electronics and losses and such..? The abysmal efficiency of RTGs meas you will need at least a ~100W heat source to power the thing......ice is a very good insulator.....

I would very much like to see a plot of EM wave attenuation vs frequency for ice so that any "windows" could be identified and the necessary transmitter power could be constrained with higher confidence.

Hmm http://www.phys.hawaii.edu/~anita/web/project/meetings/fall03/Ice%20Measurements%20-%20Barwick.pptlooks interesting...

Posted by: BruceMoomaw Sep 20 2005, 04:45 PM

There are two relevant JPL Technical Reports on this design. Unfortunately, JPL's technical-report server seems to be offline for now, so I've attached both reports.

Actually, each transceiver would use a mere 0.12 W power source, hooked up to a capacitor to allow periodic bursts of 1.3 W transmission power. So that's why there's no RTG ice-melting problem.

Posted by: BruceMoomaw Sep 20 2005, 04:48 PM

And here's the other JPL report.

Posted by: deglr6328 Sep 24 2005, 09:00 PM

hmmm! very interesting thank you!

Posted by: Roly Oct 23 2005, 04:49 AM

Was anyone at the recent (October) OPAG meeting where the new Europa Orbiter was due to be discussed?

The October report and documents aren't up yet, but surely it can't be too long now. Wonder how the talks with ESA went? Hope there was some more support for the 2013 opportunity, given the extra dry mass that could be delivered (probably enough for the soft lander studied by Balint, Nov. 2004).

Roly

Posted by: BruceMoomaw Oct 24 2005, 05:00 AM

I wasn't able to make it to OPAG, and have been monitoring their site for news on the presentations and final report from the October meeting. They haven't turned up yet, but I expect them soon.


http://www.lpi.usra.edu/opag/meetings.html
http://www.lpi.usra.edu/opag/reports.html

Posted by: Richard Trigaux Oct 24 2005, 09:54 AM

Why not ultrasonic communication? Sounds transmit well and far in solid mediums, and there would be no need of lines, repeaters and the like. I see well the penetrator having an array of piezoelectric crystals on its top, it would even be directive. On the countrary a radio link could not work if there is a fault or ice layer at 0°C soaked with salty water.
After, if the penetrator has a density between water and ice, it would float at the bottom of the ice and collect many molecules with a filter.

And with no added cost this sonar (call it by its name) would be a wonderfull mean to probe the ice crust, faults and galeries, and above all to probe the ocean itself, its depth, eventually layers and currents, floating objects, and the ocean floor...

fascinating: an ultrasonic "image" of volcanoes from the rocky core of Europa... "black smokers" (thermal vents) would be already fine.

More and more: the penetrator abandons its floater, and sinks to the rocky floor itself, and takes photos of it, eventually showing weeds and living forms...

Wow!



And on the surface?
A repeater left on the surface could send enough power (like Huygens did) to be picked from Earth (with a slow bit rate. Of course if there is an orbiter to relay data it would be better). If the repeater is buried in ice, just its radio antenna out, it could work for months and years, much compensating for the slow bit rate.

Posted by: BruceMoomaw Oct 24 2005, 09:01 PM

The presentations from the third OPAG meeting have just arrived: http://www.lpi.usra.edu/opag/oct_05_meeting/agenda.html . (The final report from the meeting isn't available yet, though.)

Posted by: ljk4-1 Oct 25 2005, 04:27 PM

Though this may sound terribly obvious, any Europa landers/ocean explorers had better be designed to last a long time if their main goal is going to be the search for life on that Jovian moon.

Unless the ice crust is encrusted with dead microbes or such similar creatures and their alien jellyfish counterparts are saturating Europa's ocean, I do not want to end up with the same situation as the Viking landers, who were stuck on two tiny spots on Mars and had scientists and the media declaring the Red Planet a dead world (again) when a few scoopfuls of dirt revealed no native microbes. Europa will require a long exploration.

To add: The global ocean on Europa is estimated to be *60 miles* deep. Thankfully in one sense the moon's much smaller mass makes the bottom water pressure on Europa no "worse" than that found in the deepest parts of the Pacific Ocean (7 miles down), but if there are black smokers and alien versions of red tubes worms and giant crabs living around them, can we design a probe that could make it all the way to the bottom of the Europan Ocean and return the data to Earth?

Another question: Life may be able to survive on Europa in its present state, but based on what we know, could it ever have gotten off to a start in the first place?

Posted by: BruceMoomaw Oct 25 2005, 10:35 PM

The reply to the second question is simply: we don't know. We don't know whether life could have evolved out of prebiotic molecules on Earth had the water been as acid and/or saline as Europa's appears to be; there has been at least one abstract I've read expressing doubt, but given our stupefying continuing level of ignorance about how the chemical process occurred on Earth itself, we just don't know.

As for the first question: even if we don't get all the way down to isolated "smokers" on the floor of Europa's ocean, we should be able to detect microbes (or their remnants) from such locations spread uniformly through the ocean water -- after all, that's how life on Earth gets transferred from one isolated smoker to another and so survives after the first smoker finally goes out. And if the alternative theory is true that Europan microbes may derive their nourishment instead from chemicals manufactured by radiation in Europa's upper ice layer and then gradually transferred down to the ocen by geological processes in that ice layer, the principle is even more true -- in fact, in that case the life would probably be concentrated at the TOP of the liquid-water layer.

This also leaves the question of whether we can find evidence of microbes in Europa's liquid ocean without even having to bore down through the ice layer to the ocean, by instead analyzing the surface ice itself to look for such remains transported up to the surface by those same slow geological processes in the ice layer. The consensus seems to be that this is a real possibility -- but, since there's a thin layer of brittle supercold "nonconvective" ice 1-3 km thick on top of the warmer main ice layer which slowly convects (and which even perhaps carries pockets of still-liquid brine upwards), we are going to have to be careful to choose landing sites that look likely to have had buried material erupted all the way up to the surface. (There are several types of Europan surface features that show promise of this, which is another reason why we do need a Europa orbiter first to pick out good landing sites.)

Posted by: Richard Trigaux Oct 26 2005, 09:02 AM

Yes, good approach in a first time, before trying to reach the bottom of the ocean (what I think possible but more complicated). But the very upper layer of ice (about 1m) is exposed to strong radiations, and thus sterilized, and anyway not representative of the global ice chemistry. So we need to drill from the very first landing, even if only 1-2m. For this reason penetrators were proposed (sticking themselves in ice like an arrow, which solves the problem of soft landing) or using a more classical drill, or a heat source able to melt ice. (RTGs were proposed, but RTGs are weak, a chemical source would perform better for this very purpose). A tip would be to place all the electronics into the drill, so that it is protected from radiations and it can last for much longer, very useful if it carries a seismometre.


Also a RTG was proposed to melt the ice down the ocean. But are RTGs powerfull enough for this? I would rather see a bot with a screw-shaped nose and a body with fins, like in sci-fi novels, running with a high gear rate, it would be much more power-efficient and faster than just melting ice. We have plenty of places on Earth to test this, in the Antarctic ice shelds. If there are interesting results from a surface examination, there will be a strong support for the idea of looking at the botton of the ocean.

Posted by: Ames Oct 26 2005, 02:03 PM

The beauty of an RTG is that it creates a LOT of "waste" heat that can be put to use here for "free".
Also the electricity generation efficiency can be increased if there is an effective cold sink.

So an RTG probe is Perfect - as long as you don't hit a buried rock/meteorite.

Nick

Posted by: BruceMoomaw Oct 27 2005, 01:05 AM

If they do add a small lander to the first Europa orbiter -- and that is a very big "if" -- I've been a fan for some time of making it a penetrator rather than a surface lander, for a whole swarm of reasons:

(1) Such a penetrator can punch down a meter or two into the ice just by impact, giving it a good chance of getting below the radation-modified upper layer. (As far as I'm concerned, no lander that doesn't drill down that far is worth sending.)

(2) It could couple a seismometer -- the second most important instrument for a Europa lander, according to the science working group -- to the crust far more firmly than a surace lander.

(3) It would bury itself in the ice deeply enough to be shielded from Jupiter's radiation -- a very serious problem for an exposed surface lander.

(4) It could land on virtually any kind of terrain, no matter how rugged.

As far as I can tell, its ONLY disadvantage is that it would have more trouble getting post-landing surface photos -- but it could carry a descent camera and memory buffer to record and later play back the last few images before impact to get imaging data almost as good.

Sure enough, Paul G. Lucey -- the Univ. of Hawaii scientist who has proposed the "Polar Night" Discovery-class penetrators to look for lunar ice (they would weigh only 65 kg, penetrate 1-2 meters into the surface, and carry mass spectrometers which have already survived impact tests at four times the planned landing speed) -- is now proposing "Thunderbolt", a mission to look for Europan surface organics. He hasn't yet described it -- and I'm still waiting to hear any details from him -- but it is surely another penetrator mission.

However, there's another problem, as Chris Chyba pointed out in "Europa As An Abode of Life": the probe may have to process one hell of a lot of meltwater to filter out enough organics for study -- quite possibly 100 times more than any pentrator or small surface lander could possibly collect. We may have instead to fall back on a larger and later surface lander with an attached heated melt probe capable of melting down at least 100-200 meters, and filtering all the large amount of meltwater which it produces in the process. And while the waste heat from an RTG would do just fine to generate the melting heat -- that's been the plan from the start -- if Europa's ice is as highly saline as many think, a salt crust would build up ahead of any simple melt probe. It may need both a melting head AND a rotating drill head to chew through the accumulated salt. In any case, I don't see any way to put either of these on a penetrator.

Posted by: ljk4-1 Nov 10 2005, 05:25 PM

Here's a use for an Europa Ocean Probe - as a neutrino detector!


Paper: astro-ph/0511243

Date: Wed, 9 Nov 2005 17:14:51 GMT (304kb)

Title: Development of Acoustic Sensors for the ANTARES Experiment

Authors: Christopher Lindsay Naumann, Gisela Anton, Kay Graf, Juergen Hoessl,
Alexander Kappes, Timo Karg, Uli Katz, Robert Lahmann and Karsten Salomon

Comments: 5 pages, 3 figures. Proceedings of the ARENA 2005 Workshop
\\
In order to study the possibility of acoustic detection of ultra-high energy
neutrinos in water, our group is planning to deploy and operate an array of
acoustic sensors using the ANTARES Neutrino telescope in the Mediterranean Sea.
Therefore, acoustic sensor hardware has to be developed which is both capable
of operation under the hostile conditions of the deep sea and at the same time
provides the high sensitivity necessary to detect the weak pressure signals
resulting from the neutrino's interaction in water. In this paper, two
different approaches to building such sensors, as well as performance studies
in the laboratory and in situ, are presented.

\\ ( http://arXiv.org/abs/astro-ph/0511243 , 304kb)

Posted by: ljk4-1 Nov 11 2005, 05:39 PM

Anyone know if clay minerals exist on Europa, or could exist?

http://www.spaceref.com/news/viewpr.html?pid=18272

Posted by: Roly Nov 16 2005, 04:11 PM

I know this has come up before but is it possible to do a Europa fly-by within a Discovery cost-cap?

Given that the Europa Orbiter is going to be 2012 at the earliest, surely there is scope for someone to propose something for Europa at the next Discovery AO.

I don't know that much about the design of orbiters, and this may
demonstrate (and probably does) some fundamental misconceptions, but I was
curious about a return to fly-by missions instead of orbiters like Galileo,
Cassini, EO etc. From what I have gathered, for many missions, the largest
problem is the energy required to brake into science orbit, particularly
where there is no potential for aerobraking, meaning a huge percentage of
the mass budget must be spent on a powerful engine and the requisite
propellant. I was under the impression that these problems were vastly
reduced in fly-by trajectories (?) With VEEGA trajectory perhaps this would be possible on a very economical LV (though it seems everything going forward is flying on Delta IV and Atlas now, not Delta II?) Okay so not a Taurus but there must be something in between Taurus and Delta/Atlas EELVs.

So instead of spending mass on an large engine with enough fuel to get into
a science orbit, couldn't the spacecraft instead focus on acquiring a huge
amount of data over a very short period of time in a low-altitude fly-by?
It would then sample a small area of the target at high-resolution.

It could carry (and I'm only guessing, the exposure/integration
times/pointing accuracy might make it truly impossible) stereo cameras and a
high
resolution imaging spectrometer on a motion compensation
scan-platform. All would operate
simultaneously, with power from advanced Solar arrays (Rosetta heritage?) lithium-ion batteries,
which would be charged during the cruise phase by the array to make up for any
power deficit during the very short and high-demand encounter phase. They could even be augmented with lithium primary batteries if required. The
spacecraft would be equipped with extremely wide and fast data busses,
caching the acquired data to memory and writing it out to solid-state disks
for later playback. No-RPS, easier admin. burden, compatibility with Discovery AO.

It would record this to high-capacity solid-state data recorders (multi-100s
GB), and then replay it once it had left its target, potentially over a
period of months or even years, depending on how much power was available,
local limits on the downlink and so on. This eases DSN management perhaps? Offline compression would be helpful, especially given that there might be issues with heavy compression in the Jovian environment (I'm suprised ICT did so amazingly well).

As an added bonus some of the
radiation hardening requirements would be reduced, as the spacecraft would
not be remaining in the most dangerous areas for a prolonged period,
repartitioning mass away from shielding and to the science payload. Lithium polymer batteries might be decent for providing some incidental shielding in any case.

I suspect I am heavily overestimating the ability of the scan platform to
provide adequate motion compensation, and the amount of time needed for the
instruments to acquire data - but I was curious about the idea because it
leverages some of the things that have become much better and cheaper over
time, like bus bandwidth, memory, disk write performance, processing power,
detector resolution/sensitivity - to replace things that have not, like
putting large amounts of propellant and engine mass into orbit.

I read a bit about Firebird recently, which seemed to utilize a similar approach. Perhaps there is geometry which would make possible a "Fire and Ice bird" (like the old JPL 'Fire and Ice' theme) ?

I've wondered out loud about this on other forums but no-one ever seems to have any ideas (other than Orbiters are better, which of course they are...)

Roly

Posted by: dvandorn Nov 16 2005, 05:00 PM

It's not just that orbiters are better (though that rather goes without saying, in many ways).

First, there is the issue of time-and-change-dependent observations. If one of your goals at Europa is finding places where the ice crust is thin enough to provide some form of access to the ocean below, you need to observe Europa over a matter of weeks and months and track the movements of the crust.

Second, there is the issue of coverage. No matter how you design your approach trajectory, you're going to be able to observe only a tiny fraction of the surface during a fast fly-by. And there will only be one side sunlit during that snapshot. So no matter how capable a fly-by probe might be, its choice of what it can view is severely limited.

Lastly, there is the politics of funding. We are *barely* to a point where we can think about getting Congress to fund a Europa Orbiter mission -- a mission that we really need, in order to answer fundamental questions and set up a possible landing mission (and, more ambitiously, a mission to explore the subsurface ocean). Because of the points I raised above, a fly-by mission is far less likely to provide those answers, no matter how much data it returns about a very small portion of Europa. And now, *in addition* to funding an orbiter for a billion or more dollars, we're going to ask them to fund an interim fly-by mission for another half a billion dollars? If we were to do that, we'd end up with either the less-useful fly-by and NO orbiter, or (more likely) just getting laughed off the Hill for trying to get them to fund *two* different missions to the same chunk of ice millions and millions of miles away -- a chunk of ice most of them think is worthless in the first place.

Is that a little better answer than a simple "orbiters are better" statement?

-the other Doug

Posted by: JRehling Nov 16 2005, 08:13 PM

Something that the continued Cassini imaging of Saturn's many moons has made me aware of is the value of terminator observations, which are even more severely limited than observations intended merely to map albedo. A single flyby will show a world in 50% illumination, but only a small fraction of the surface in the low sun angles near the terminator. When Cassini's mission is done, we will be able to generate low-resolution DEMs for all of Saturn's inner icy moons, which would be very hard to achieve by performing direct measurements of altimetry for so many worlds (JIMO comes to mind).

Amateur astronomers know how dull an object the full Moon is, and Mariner maps of Mercury show how much more detail is seen at the terminator than mid-disk. An orbiter (even a Jupiter-orbiting craft) would provide not just twice the imaging of Europa -- in terms of terminator observations, it would provide perhaps 100 times as much imaging.

Any flyby of Europa better be a sample return.

Posted by: Richard Trigaux Nov 16 2005, 08:16 PM

At rough guess, it is possible, if there are basaltic rocks at the bottom of the ocean. clay is the usual result of slow chemical attack of such rocks by water. But perhaps the chemistry of Europa water is very different of Earth rainwater, so the result may be different. And if Europa has a carbon layer around its rocky core, clay becomes unlikely.

That this clay may arrive at the surface is another question. Europa shows strong evidences of the ice layer being broken is small icebergs and turned upside down, from some catastrophic events. So things in the ocean can reach the surface. That some clay from the bottom of the ocean could reach the surface needs a double transfer, first into the ocean, second into the ice layer. Maybe the catastrophic events can achieve both in the same time.

So a lander could search for such particles in the molten ice. From them it could give clues about the core of Europa

Posted by: Richard Trigaux Nov 16 2005, 08:23 PM

Would not an economic trajectory achieved with a ship in orbit around Jupiter, using the moons as a gravitational assistance, until getting a nearby circular orbit at the level of Europa, which provides the most economic way to brake and land?

The only inconvenience of this is that it would require some months, and also staying into radiation belts for a long time. So what is gained in fuel may be lost in hardening the electronics.

Posted by: BruceMoomaw Nov 17 2005, 02:06 AM

That is exactly the plan that has ALWAYS been written for Europa Orbiter -- it will make, first, about 6 flybys of Ganymede and about 3 of Callisto, and then (in the so-called "Tour Endgame") as many as a dozen close flybys of Europa itself to almost match orbits with that moon before orbital insertion. (For a drawing of a typical such tour, see page 10 of http://www.lpi.usra.edu/opag/jun_05_meeting/presentations/EGE_Mission_Study.pdf .) The whole process will take roughly 18 months, during which EO will soak up about 900 kilorads of radiation -- equal to the dose it will get during its 1 month in orbit around Europa itself.

As for aerocapture for EO, it's been considered, but -- besides the fact that aerocapture technology won't even nearly be ready for an EO launch by 2014 -- I was told at the COMPLEX meeting that studies indicate that aerocapture doesn't provide much of an advantage for this particular mission. (The plan, by the way, is also to use a flyby of Ganymede to help brake the craft into orbit around Jupiter initially, as Galileo used a flyby of Io for that purpose.) But -- even with all this gravity-assist -- half of EO's weight must be propellant. This is simply a difficult mission.

Posted by: BruceMoomaw Nov 17 2005, 02:18 AM

Another description of the "Tour and Endgame" can be found on pg. 23-26 of the most detailed description of the original Europa Orbiter concept at http://outerplanets.larc.nasa.gov/outerplanets/Europa_MPD.pdf . (One nice recent development: calculations now indicate that the total radiation dose that EO will get during this mission is less than half of the originally estimated 4 megarads. This by itself lops 200 kg off the needed shielding weight, and thus about 400 kg off the total spacecraft weight.)

Posted by: BruceMoomaw Nov 17 2005, 02:18 AM

Also, you'll notice that the Endgame involves only about half a dozen Europa flybys, rather than a dozen as I stated above.

Posted by: ljk4-1 Nov 17 2005, 12:40 PM

Perhaps this will require a separate topic, but what will it take to put a lander on Io? Just imagine what surface images will look like from there!

Posted by: BruceMoomaw Nov 17 2005, 01:18 PM

That will be a while coming -- the radiation level at Io is 30 times that at Europa!

Posted by: Roly Nov 17 2005, 02:29 PM

Thanks for the replies about the orbiters - the constitute the most compelling explanation yet of why you don't bother with fly-by missions unless the target is exceptionally hard. I can see the political point is also important when there is a [F]lagship class mission looking for money (that's a capital 'F' for the large clas flagship that EO will doubtless end up being).

Counting the days until EO arrives. I wish Juno could do some science on the Galilean moons, but I guess that's totally not the point, given the orbit. New Horizons Jupiter encounter should be great.

Roly

Posted by: BruceMoomaw Nov 17 2005, 08:31 PM

Yeah, it's been made clear to me by Scott Bolton that they don't WANT to fly Juno close to any of the Galilean moons, even if they get the chance. (Although I would presume that its camera could make some observations of Io's continuing activity.)

In fact, he's now made one interesting point that I had never thought of: Juno is definitely NOT going to have a long prolonged mission. It will have taken a considerable radiation dose by the end of its one-year primary mission, and they want to make sure it doesn't break down before they have a chance to deliberately crash it into Jupiter to make sure it doesn't eventually hit Europa. He's talking about an extended mission of -- at most -- one month, and they will in fact be monitoring its behavior carefully on the chance that they may have to end its mission a little ahead of schedule. (A landslide majority of its useful science will have been done by the first 6 months.)

This one is scientifically aimed at Jupiter -- period -- and (like Mars Climate Orbiter had it succeeded) it's going to do very little that will be of interest to the general public.

By the way, its launch has definitely been bumped now into July 2010 or August 2011.

Posted by: Marslauncher Nov 30 2005, 02:05 AM

Is the Europa Orbiter Still on? on was it replaced by Juno?

Just saw a program on Science Channel that mentioned it

Posted by: Decepticon Nov 30 2005, 02:09 AM

You know this is very confusing lately. I was gonna suggest a area on this board with a listings of approved missions and future mission as well as canceled/on ice missions.

Posted by: BruceMoomaw Nov 30 2005, 02:34 AM

No, Juno AND the Europa orbiter (under its new name, "Europa Geophysical Explorer") are both planned, although EGE won't get its official program start until 2007.

However, one thing that is on hold for now is the previous plan for a Deep Jupiter Multiprobe mission, for which they won't give any go-ahead until they examine the Juno results -- that is, not for quite a while (since Juno won't arrive till 2016). There has recently been a very dramatic, but apparently firm, change in the science community's attitude toward the giant-planet entry probe program, which is yet another item in my "Astronomy" article that I must leave dangling for now.

Posted by: odave Nov 30 2005, 03:08 AM

"Astronomy" needs to pay you a sales commission, Bruce

Any news on what issue your article will appear in?

Posted by: AlexBlackwell Nov 30 2005, 08:52 PM

Or deduct from what they've paid him since he's dropping so many hints

Seriously, though, it's a good thing he didn't submit the article to http://www.sciencemag.org/ or http://www.nature.com/nature/index.html because his comments here, as helpful and useful as they are to the forum, might constitute "http://www.sciencemag.org/about/authors/prep/gen_info.dtl#prior," which both journals use as grounds for rejection or refusal to publish.

Posted by: BruceMoomaw Dec 1 2005, 12:27 AM

My article will be appearing in either the February or March issue. Unfortunately, I ended up with enough material to write a 9.5 page article (AFTER extensive trimming), and so the editors will be hacking it down to 4 pages -- and I'm not sure what complete sections they're going to cut out to do so. I will, at any rate, try to get "SpaceDaily" to publish whatever info "Astronomy" doesn't; and anything relevant that gets cut out there will get put into this blog at some point, rest assured.

Posted by: mars loon Dec 2 2005, 07:20 PM

Too bad about the extensive cuts. did you learn that after it was already written?

Posted by: Bob Shaw Dec 2 2005, 11:59 PM

Bruce:

Perhaps it was a slip of the keyboard, but the word 'blog' caught my attention. Do you produce one? Do you have *time* to produce one?

I'm sure we'd all be fascinated, were you to do so - even when we (quietly) disagree with you, your comments on the unmanned spaceflight scene are without peer!

Bob Shaw

Posted by: BruceMoomaw Dec 3 2005, 11:18 AM

Nope, no blog -- I've never quite had the time and/or the nerve. (One recent "New Yorker" cartoon shows one dog telling another: "I considered starting a blog, but I finally just decided to go in for pointless barking instead.")

As for the article, they told me from the start that 4 pages was the length. The trouble is that whenever I attend one of these damn conferences, I get enough interesting material for SEVERAL articles, and then go through the torments of hell trying desperately to hack a 12 to 15-page article down to a few pages while the article bleeds and screams piteously. As with my 2004 article on the MER-A landing for "Astronomy", I finally just had to throw myself on the mercy of the editors by submitting an oversized article and letting them do the dirty work. (A far cry from those bright college days when I was straining desperately to inflate puny term papers.)

Posted by: Decepticon Dec 3 2005, 12:04 PM

And I've always wondered why the articles are so fricken short.

Posted by: mars loon Dec 3 2005, 02:43 PM

Bruce, what month in 2004 was that?

Also, hard to say if you used the best approach with the editors. Did you consider 2 versions? one short, one long.

In your opinion did they retain the best stuff? or would you have preferred alternate surgery?

I/we can sympathisize with your pain and torment.

Posted by: mike Dec 3 2005, 10:02 PM

Editors are evil. They should be outlawed.

Posted by: Rob Pinnegar Dec 3 2005, 10:50 PM

I guess that, if they weren't short, there'd be no room for the pretty pictures. That was something that _did_ bother me about Astronomy when I was a kid. But I guess that full page images of Saturn are probably a big selling point to the general public.

Posted by: Bob Shaw Dec 3 2005, 11:39 PM

Bruce:

I dunno what the copyright issues are (hopefully, you'd be paid *twice*), but perhaps the editors of Astronomy could be persuaded to do a web-only version of your articles, perhaps a month or two after the print version, and which would be somewhat longer? It'd be the sort of thing which might drive us guys to their website, thus giving them a double-whammy on the advertising...

There are publishing imperatives in print media which don't always suit in-depth articles, but there's no reason these days not to claim back the high ground on the WWW!

Bob Shaw

Posted by: dvandorn Dec 4 2005, 03:16 AM

Reminds me of an old Isaac Asimov short story in which a writer had been cursed by Satan such that he was incapable of writing anything except pact-with-the-devil stories. The upshot is that, after the writer died and went to Hell, the only thing he could end up submitting to the publishers in the Underworld were........


.....wait for it.....


.....pact with the Editor stories!

:::ducking:::

-the other Doug

Posted by: mike Dec 4 2005, 04:20 AM

Heh. I dare say almost everything is a pact-with-the-editor story.. and I dare also say that almost everything is dulled down and bland-ized so that it won't 'confuse anyone'. Yeah, why make people think when they can just read pap that reinforces their already long-held beliefs.. WHERE'S MY PAYCHECK SO I CAN WATCH MORE 'FRIENDS'

But I digress...

Posted by: BruceMoomaw Dec 4 2005, 06:41 AM

My MER story -- along with a 1-page piece on Stardust's comet flyby, during which I expressed my belief in a theory of the craters which I gather is still not proven, but still seems to me probable -- is in the April 2004 issue.

Both then and this time, from the very first they warned me that the final article wouldn't be allowed to go over about 2000 words. I never dreamed I'd have such trouble deciding what to cut out. I was somewhat disappointed that the finished product for MER-A simply didn't include any news you couldn't have gotten from other articles on the subject, but with that short length you just couldn't do much else. The only thing that made me really grind my teeth was that the editor took it on himself to insert a passage in which he listed a bunch of elements and described them as "minerals", thus leaving me holding the bag for looking like a scientific illiterate.

On the bright side, while I hung around JPL for the first 11 post-landing days, I finished the article just before Spirit's computer crisis, which would probably have led me to include a gloomy passage on how the mission was Certainly Doomed.

Posted by: Richard Trigaux Dec 6 2005, 04:38 PM

Here
http://www.unmannedspaceflight.com/index.php?showtopic=1647
was dicussed the idea of using unconventionnal electronics to sustain the high temperatures (460°C) at the surface of Venus.

There was mainly three methods proposed:
-unconventionnal semiconductors
-micro-sized vacuum tubes implemented witht he techniques of integrated circuits
-micro-sized electrostatic relays

I note that the two latest proposals are also suited to resist to high radioactivity levels, so that they will be a good solution for a Europa orbiter (and even a Io orbiter) by increasing reliability and removing the weigh of shielding.

Developing such techniques will need only a series of small scale test, and then after a relatively short period of large scale development, in a total duration which is not uncompatible with the launching of the mission.

Posted by: JRehling Dec 7 2005, 03:40 PM

It's seemed to me that if we found a way to transform the radiation from charged particles into energy, we'd solve two problems at once for Jupiter missions. Surely if the particles were segregated, this would be possible. I imagine the problem is that the net charge of any stream would be neutral and trying to segregate them would require more energy than you would get out of them... although I'm not *sure* that is so. If you could "split the beam" and get a net negative hitting a cathode and a net positive hitting an anode, you could run a current strong enough to power the beam splitter... in principle. Then you'd have a mission that would would *want* to fly, eg, near Io/Europa orbit. (And a generator that wouldn't much work anywhere else.)

Posted by: BruceMoomaw Dec 8 2005, 02:43 AM

Uh-uh. Back when I was posting to the Europa Icepick website, I once did the actual calculations on the energy flux from Jupiter's radiation belts -- which turned out to be pathetically small: about five orders of magnitude less than you need to power a spacecraft! The belts are splendid at poisoning solid-state electronics (or biochemistry), but as a power source they stink.

However, running a long conductive tether from a spacecraft and letting it plow through Jupiter's intense magnetic field is a very different matter -- for an orbiter of Jupiter or one of the moons, that will work beautifully, if you're willing to put up with the tether.

Posted by: Richard Trigaux Dec 8 2005, 08:04 AM

There was such an attempt by the NASA to fly a tethered satellite around Earth using this system, and it worked very well, providing a good power, except that the mechanical forces acting on the cable were stronger than expected, breaking the cable. Around Jupiter it would work well, and perhaps too around other giant planets. That will be safer than using a RTG, and potentially it could yeld more power. (RTGs too are good at poisoning electronics, although around Europa their action is smaller than the indigenous radiations)

Posted by: edstrick Dec 8 2005, 10:35 AM

"except that the mechanical forces acting on the cable were stronger than expected, breaking the cable"

Actually, they had undetected flaws in the insulation on the conductive tether, possibly some grit in the insulation or between it and the wire (not sure working from memory). It electrally shorted through to one of the pulleys or guides on the deployment mechanism, and the considerably higher ELECTRIC CURRENT than expected burned through and severed the tether. That part of the experiment worked too well... oops!

Posted by: BruceMoomaw Dec 8 2005, 12:02 PM

Yep. In fact, when I finally read about that incident in detail, I was startled to learn that it was due to a completely unexpected phenomenon that they still can't explain: they had an electrical arc run from the cable to the end of the deployment boom that -- amazingly -- continued to flow for several seconds after it had melted through the cable, while the end of the cable was drifting away from the boom. Apparently some kind of gas leaked out of the Shuttle to allow the arc, but they have never solved the mystery. This makes me a bit more inclined to forgive the Italians for having us fly that Shuttle mission twice and have it fail both times.

Posted by: Richard Trigaux Dec 8 2005, 12:53 PM

This is really odd, and cannot explained by the static charge of the shuttle: it had to receive current from somewhere else, to form a circuit with the cable. And the arc had to be pretty long, to be still sustained seconds after breaking.

There may have be some halo of gaz around the shuttle. Weren't emptying their toilets at that time? Letting some ice block stuck at the shuttle sending high flow of steam all around? This could be the origin of many "unexplained" phenomenon, water steam being especially conductive.

With my opinion this experiment should be made again, using two technological satellites, not the shuttle.

Posted by: mars loon Dec 15 2005, 11:54 PM

Some bad news about the prospects for a Europa Orbiter have just been posted by Lou Friedman of The Planetary Society

see this link:

http://www.planetary.org/programs/projects/explore_europa/update_12142005.html

first 3 paragraphs:

By Louis Friedman
December 14, 2005

In the recently passed NASA Appropriations bill, the US Congress directed NASA to begin work on a Europa orbiter and to make a request for a new start for a Europa mission project in fiscal year 2007. This was welcome news to NASA, who lost their focus on Europa when the nuclear propelled Jupiter Icy Moon Orbiter mission was cancelled last spring.

But now word has it that there will be no Europa proposal in the 2007 budget proposal that will be made to Congress early next year. The Washington Aerospace Briefing, a respected newsletter publication of Space News, is reporting that the Administration’s Office of Management and Budget is denying the Europa request on budget grounds.

The Planetary Society will fight for a Europa mission. Whether or not is in the budget request, we will lobby in Congress for its inclusion in the NASA program. Our Explore Europa Campaign is already in full swing. Having Congress insert funds in the ’06 budget was a good start, but we need to ensure support in 2007 and beyond.

Posted by: vjkane2000 Dec 16 2005, 01:52 AM

NASA's science budget is a mess -- too many missions, several with large overruns. It would be irresponsible to add a $1B+ mission into the pie until everything else gets straightened out. What might be useful, though, is some early development money next year to get things moving again.

Posted by: BruceMoomaw Dec 16 2005, 04:34 AM

The plan was to just insert about $10 million this year for initial design studies -- including making absolutely sure that they DO want to fly Europa Orbiter before any of the other possible Flagship-class missions. Once again, we have a case of the idiotic manned program eating the rest of NASA alive.

Posted by: Decepticon Dec 16 2005, 01:23 PM

I could have not said that better!

Posted by: AlexBlackwell Dec 16 2005, 08:08 PM

Not that I don't think that NASA's manned space program is becoming a larger and larger money pit, but I'd like to see hard evidence that money not spent by NASA there would be transferred over to space science. A great many legislators appropriate funds for Shuttle/ISS because the money is spent in their districts for that specific purpose. It's amazing how many people believe that eliminating billions of dollars from the NASA EMSD would automatically result in an increase for NASA SMD.

Posted by: BruceMoomaw Dec 16 2005, 11:36 PM

The very fact that Congressmen fund NASA as pork to their home districts indicates that if the manned-program budget was cut, SOME of the money thus saved would get transferred to the unmanned program.

Posted by: mars loon Dec 18 2005, 06:21 AM

I dont see how you can make that connection. Your suggestion may or may not be true

Hopefully this truly worthy mission does get funded somehow, despite the gloomy outlook.

Posted by: scisys Dec 27 2005, 05:21 PM

It has always seemed to me that the problem with the manned program is not that allocated funds are coming at the expense of the unmanned programs. The problem is that *cost overruns* in the manned program are carved out of the hide of the unmanned program. This nails you every year even after a mission is scoped and funded. Heck it even nails you during ops.

Still, this argument has been going on since forever. The reality is that the unmanned program has to live within the boundries defined by the, admittedly excessive, needs of the manned program. I don't like it but I don't see a way to change it. It is inlikely that money cut from the manned program will end up in the unmanned program. However, a reined-in manned program would be less of a yearly threat to the unmanned program and cause fewer 're-engineerings', 'budget exercies', 'descopes', 'stand-downs', 'development deferrals' ... pick your favorite euphemism for feeding the beast that is the manned program.

My personal feeling on a Europa mission is that it needs to focus on two questions: "is there (still) liquid water (for sure)?" and "where are the thinnest parts of the ice?". One has to hope the answers will be such that the justification for follow-on missions will lead to penetrators and landers, etc. The tendency towards a Galileo style tour must be avoided at all cost. It should be a Europa only tour. Otherwise the flight ops budget alone would kill the mission when you start adding all the systemic requirements for mission planning and resource allocation. I know we don't go out there very often and Jupiter ain't Mars, but I don't see any Galileo/Cassini style missions coming along anytime soon (or long term to be honest).

Perhaps a Europa mission should become a near term component of the Origins Program (would that be a good thing or more likely to kill it?)

Posted by: BruceMoomaw Dec 28 2005, 01:38 AM

Actually, the Europa Orbiter is a good deal more complex as a mission than a replay of Galileo would be, given the technology and experience we now have. Indeed, a Jupiter orbiter that makes dozens of Io flybys is one of the second-rank candidates for a New Frontiers mission -- which means, given NASA's likely change to the NF proposal rules, that they'll accept ideas for it in the next round of NF selections in 2008. Such a craft would make Ganymede and Callisto flybys anyway to keep modifying its orbit to fly over different parts of Io's surface and at different phase angles, so it could easily be turned into a mission to study all three of the remaining Galilean moons. Indeed, it could be a virtual duplicate of the Europa Orbiter but with much less onboard fuel -- the radiation shielding for EO would allow such a craft to make at least 25 close Io flybys (maybe 50; I've got to recheck my records).

In fact, since EO itself will have to make a total of about a dozen Ganymede and Callisto flybys to get into position for Europa orbit insertion, it is virtually certain to make major observations of those moons -- and Jupiter itself -- during the 18 months or so before it goes into orbit around Europa itself.

Posted by: scisys Dec 29 2005, 06:17 PM

I guess this is one of the tendencies I think probably dooms a Europa Orbiter. I really do understand the forces which would drive the desire for such observations (particularly given the loss of atmospheric dynamics data from Galileo) but such observations do not come for free. Building this into a reference mission plan will lead to instrumentation choices driven partially by such observations. It is expensive to develop such observation plans. Would there now be a scan platform? That costs in many ways (hardware design, assembly and test; ops planning software; constraint checking; etc.). No scan platform? Then you have the attendant fights over spacecraft orientation. An S/C designed to be an orbiter can be purely a nadir look design with perhaps a side look radar.

Allowing for 'cruise science' grows the flight team during what could be quiescent time. Getting into orbit aroudn Europa *is* complex. It just seems to me that a mission design that avoids any additional complexity or design drivers would have a greater chance of approval. By allowng cruise science you now require an S/C that is part fly-by and part orbiter. Throw in serviing as a delivery bus for a lander and you are starting to talk real money. As more is added, there is a non-linear increase in integration costs.

Posted by: BruceMoomaw Dec 30 2005, 02:46 AM

There has always been a firm restriction applied to Europa Orbiter designs: no supplementation or change at all in the spacecraft for pre-Europa science. That being said, the new design for the mission -- which uses Earth gravity-assist flybys, and thus allows them to carry fully half a ton of additional payload into orbit around Europa -- would seem to provide some flexibility for this possibility.

Posted by: nprev Dec 30 2005, 08:51 AM

I wince at asking this given the tight budget constraints, but has any thought been given to maybe adding a simple surface science experiment to EO? Something like the Deep Space 2 penetrometers with conductivity, salinity and maybe seismic sensors or a sonar transducer/receiver for crust mechanical property measurements could provide a LOT of vital information that is otherwise quite difficult or impossible to interpolate from remote sensing. A low-power low-rate UHF FSK data link would be quite sufficient for the probe support equipment suite, I would think...

Understand that the necessary sterilization procedures might prove too onerous and expensive for this to even be considered, aside from the existing budget problems...but the beauty of this concept is that most of the instrumentation I described has already been engineered to rugged deep-sea oceanographic standards as COTS equipment. NOAA uses this stuff all the time (and, no, I wouldn't expect them to punch through to any hypothetical ocean...but wouldn't that be cool!!!! )

Posted by: BruceMoomaw Dec 30 2005, 02:45 PM

The debate over whether to use that huge new payload margin to put a small piggyback lander on EO was one of the primary subjects at the November COMPLEX meeting, since there has already been quite a lot of design work on possible landers with varying degrees of complexity. (In particular, there was an unbelievably long drawn-out wrangle over whether a seismometer and magnetometer might be worthwhile on a small short-lived lander, which eventually began to resemble that 10-year debate among the savants on Jonathan Swift's Laputa over how long to boil a 3-minute egg.)

The group was nowhere near a recommendation when the meeting ended, but the impression I got was that there wasn't much enthusiasm because it is probably impossible for such a small lander to drill down deep enough into the surface to find any organic compounds that haven't been hopelessly scrambled by Jupiter's radiation -- and without that, the science return from a lander is just not that high. The leader of the team of graduate students who did the hypothetical "Endurance" lander design study described in a poster at the December AGU meeting told me that his group had reached the same conclusion: it would probably be more scientifically productive to put that extra mass into more Orbiter science instruments, a higher bit-rate communications system, and (especially) more shielding to prolong the orbiter's working lifetime in Europa orbit. (It takes 100 kg of shielding to extend the Orbiter's lifeime there by 1 month.)

Posted by: nprev Dec 30 2005, 07:19 PM

Oh, well; at least it was considered. Thanks, Bruce!

I am surprised that surface (or just below!) conductivity/permittivity studies wouldn't be considered high priority; we could learn a lot about the amalgam of salts present in the crust--and therefore those present in the possible ocean--that way.

Posted by: AlexBlackwell Jan 26 2006, 10:54 PM

Just to follow up...

In the January 27, 2006, issue of Science, Jeffrey Plescia, of JHU/APL, in one of http://www.sciencemag.org/cgi/content/full/311/5760/469a responding to Science Editor-in-Chief Donald Kennedy's Editorial in the November 25, 2005, issue (http://www.sciencemag.org/cgi/content/short/310/5752/1245"), closes with the following:

Posted by: BruceMoomaw Jan 26 2006, 11:20 PM

No "fiscal windfall", true. But it strikes me as an exaggeration to say that NASA would "not continue" without a major manned flight component. After all, the things keeping NASA going are (1) its actual valid justifications, and (2) its pork value -- and the latter includes spending on unmanned as well as manned projects. No doubt NASA's total budget would shrink, but it's very implausible that it would "not continue" -- instead, a lot of the Congressional and Presidential hunt for politically useful space pork would be transferred to the unmanned space program, leading to some degree of increase in spending the latter, and quite possibly a large one.

But that takes us to the obvious next question: what if NASA SHOULD vanish, and what if the unmanned space science program should also be radically shrunk after the manned program is eliminated, on the grounds that most space science projects are appallingly low in scientific cost-effectiveness compared to spending on other types of scientific research? We ourselves would certainly regret that, but you would have a hard time coming up with a morally convincing argument against it.

It's hardly surprising, however, that Plescia is pushing the manned program for all he's worth -- he has always done so, although virtually the only argument he's ever been able to come up with for the science value of humans rather than robots on the Moon is that the latter would have more trouble doing deep drilling operations.

Posted by: ljk4-1 Feb 6 2006, 06:00 PM

Planetary Society Charges Administration with Blurring its Vision for Space Exploration

The Planetary Society Cites Cancelled Plans for a Europa and Other Science Missions

Pasadena, CA, — The NASA Budget released today shortchanges space science in order to fund 17 projected space shuttle flights. Despite recent spectacular results from NASA's science programs, this budget puts the brakes on their growth within the agency. It seriously damages the hugely productive and successful robotic exploration of our solar system and beyond.

According to this budget, flight projects that were already underway, such as the Space Interferometry Mission, will be delayed. Others, such as the Terrestrial Planet Finder and a mission to Jupiter's moon Europa, will be deferred indefinitely. Furthermore, the new budget slashes funding for the fundamental space science that makes such missions possible and turns raw data into discoveries.

http://www.planetary.org/about/press/releases/2006/0206_Planetary_Society_Charges.html

Posted by: Decepticon Feb 7 2006, 12:53 AM

Outrage

Posted by: RNeuhaus Feb 7 2006, 01:03 AM

Maybe, there will more robot exploration between Earth and Moon. These will be the first robots as a model to conquer to other planets. I bet after that, there will be a leap technology to explore others bodies of our solar system. It is a just a change of aim but the robot technology will continue improving and the there will be no lost time.

Rodolfo

Posted by: nprev Feb 7 2006, 02:09 AM

Agreed.

Bet things would be different if JSC & KSC were located in states other than Texas & Florida, respectively...

Posted by: BruceMoomaw Feb 7 2006, 02:42 AM

I suppose I do have something to thank LBJ on in this respect -- even if he was the one who almost single-handedly persuaded JFK to launch the Moon Race (while telling his own friends that he had done so mostly to provide economic pork for the South). The Manned Spacecraft Center was originally supposed to be built in Vallejo, California before he rediverted it to Houston. Had he not done so, it would have been my own state's Senators who were constantly making dishonest jackasses of themselves on the subject of manned space exploration.

Posted by: Jeff7 Feb 7 2006, 03:19 AM

Dear ESA,
As you are aware, our current administration has some "issues" with our space budget. Please consider a sophisticated robotic mission to Europa. I mean really, Europe, Europa - the PR writes itself!
Thank you,
Jeff

Posted by: ljk4-1 Feb 7 2006, 03:59 PM

Spaceflight:

* Europa Mission: Lost In NASA Budget

http://www.space.com/news/060207_europa_budget.html

NASA's newly issued budget has lowered a flagship mission of exploration to
half-mast. Backed by scientists and study groups, a mission to Jupiter's moon
Europa is missing in action within the pages of NASA's Fiscal Year 2007 budget
unveiled yesterday.

Interesting quotes:

One additional payload on Europa Explorer: a simple lander.

Pappalardo said a lander is still being bandied about, but carrying what kind of technology and at what cost are questions awaiting answers.

“We’re not going to search for life with this mission. But just like the Mars rovers in their search for habitable environments…we’re going to characterize the habitability of Europa,” Pappalardo said.

An orbiter to the moon of Jupiter would allow a now sketchy view to become sharp as to how this world works, Pappalardo concluded. This mission, he said, has compelling science and broad community support and “we’re ready to go.”

and:

Also, the European Space Agency (ESA) is currently studying the Jovian Minisat Explorer (JME). The JME focuses on exploration of the Jovian system and particularly the exploration of its moon Europa. The ESA study is also looking into deploying a compact microprobe onto Europa to perform on-the-spot measurement of the moon’s ice crust.


* NASA Seeks 30-Percent Increase for Exploration Program

http://www.space.com/news/060206_nasa_budget.html

Efforts to replace the space shuttle fleet with new Moon-bound spacecraft would
receive big spending increases under NASA's 2007 budget request, while nearly
every other part of the U.S. space agency's budget would be held flat or
decline.


* SPACE NEWS: Policy or Politics? NASA Accused of Intimidating Climatologist

http://www.space.com/spacenews/businessmonday_060206.html

NASA is battling accusations that it tried to stifle its top climatologist, a
man well known for speaking his mind about the causes and consequences of global warming.

Posted by: Redstone Feb 7 2006, 06:32 PM

Remember this budget is just a request. Congress has the final decision on how much gets allocated to NASA. For several cycles, the Administration allocated no money to New Horizons, but Congress funded it anyway, and now it is on its way to Pluto. And it was Congress that told NASA to prepare to start a Europa mission last year. I would not be surprised if some small part of the 30% boost to ESMD is shaved off and tranferred for a Europa mission. The same goes for SIM. The important thing is that the scientists, advocacy groups and media push for it. That looks to be happening.

Posted by: vexgizmo Feb 8 2006, 09:52 PM

National Geographic:
NASA Budget Diverts Funds From Science to Spaceships
http://news.nationalgeographic.com/news/2006/02/0208_060208_nasa.html

See my post in
Policy and Strategy > The Creature That Ate Nasa Takes Another Big Bite
as to what you might be able to do to help remind Congress about Europa.

Posted by: JRehling Feb 9 2006, 10:43 AM

Let me suggest a conspiracy theory behind the EO cancelation. While money is sure to be tight, and an axe is going to be aimed somewhere, the choice of EO and TPF may have been performed by someone who wanted to see as little as possible in the way of cuts and reckoned slyly that those two missions are most likely to get a reprieve (by Congressional fiat). If so, putting them in harm's way, which they will, as my theory goes, escape, leads to the least eventual cuts, because putting some other projects in harm's way might have been harder to reverse.

In other words, the sort of campaign that saved NH is not to be considered an extraordinary follow-on to "the system", but part of the de facto system. And in some sense, these missions aren't in jeopardy until a similar movement fails to save them. Warm oceans nearby and earthlike worlds far off should perk some interest, what say...

Posted by: Analyst Feb 9 2006, 10:55 AM

I hope you are right.

Posted by: gpurcell Feb 9 2006, 02:22 PM

Yeah, that was my thought as well. THe old "close the Washington Monument" trick.

Posted by: elakdawalla Feb 9 2006, 04:00 PM

We've always been pretty sure that that's what's going on with the Voyager 'cancellation.' But I think Europa and TPF are different. Europa, at least, will need to be a big, big mission, and it's just not going to work to "save" it every year by congressional action. It really needs to be built in to NASA's very long term plans over more than one decade. Engineers and particularly scientists will need to devote large chunks of their professional careers to getting it going, and despite people's devotion to Europa, I think it would be awfully hard to take the risk to your career to devote so much professional time and energy to a mission that is at risk of being cancelled every year. New Horizons was hard enough to do that way, and it is a much simpler mission. NASA has got to make a long-term commitment to Europa for a mission to work.

--Emily

Posted by: BruceMoomaw Feb 9 2006, 09:05 PM

I agree with Emily. These proposals are simply too big to be subject to this kind of subterfuge to preserve them. Moreover, Congress has already made it clear (with justification) that they are not going to spend any more on NASA as a whole - and the Administration has made it clear that it considers manned spaceflight much more important than unmanned spaceflight and space science.

As for WHY the Administration considers it so much more important -- well, we just got another clue yesterday, when the House GOP (as a consolation prize to Tom DeLay for getting the boot as House leader) gave him seats both on the Appropriations Committee, and on the subcommittee which oversees the Justice Department (which of course is currently investigating DeLay himself) and which also (as a result of DeLay's recent redesign of the House committee system) controls NASA. (The Manned Spacecraft Center is of course now in DeLay's district, and that earlier Washington Post article hinted that he was already the main figure keeping Shuttle/ISS from being trimmed back):
http://news.yahoo.com/s/ap/20060208/ap_on_go_co/delay_appropriations;_ylt=Ati99m85pYT69MCWIMPeIiFp24cA;_ylu=X3oDMTA5aHJvMDdwBHNlwN5bmNhdA

Both the White House and the GOP are still terrified of DeLay -- he is, after all, the one who knows where all the bodies are buried in the gigantic nationwide Tweed Ring that the GOP has now set up in this country -- and it's a safe bet that they will continue to give him everything he wants, if they think they can get away with it, until the moment when he is either indicted or defeated for reelection. After he's gone, we may see some fairly major readjustments in the NASA budget as a side effect.

Posted by: AlexBlackwell Feb 10 2006, 01:30 AM

No argument here, Emily. Frankly, I don't believe any putative "Europa Underground" is going to achieve for Europa Orbiter (EO) what the Pluto Underground effort did in finally getting a Pluto mission launched. As you noted, there are too many fundamental differences between EO, or at least the type of mission recommended by the decadal survey, and a Pluto flyby. No matter how one slices it, EO is going to be a Flagship-class mission (i.e., "Battlestar Galactica"-class). The problem is that, as recommended in the aforementioned decadal survey, NASA will probably be able to fly Flagships only once per decade. With Mars sample return (another Flagship-class mission) preeminent, I don't see how EO can fly before 2020 without some massive amounts of paradigm shifting.

At times like these, one can only look back on the now-defunct Outer Planets/Solar Probe (OP/SP) Project with a mixture of bitterness and, believe it or not, humor. Ludicrous as it seems now, under the reign of Captain Crazy (Dan Goldin), the entire OP/SP effort (from cradle to grave), which included three missions (EO, Pluto-Kuiper Express (PKE), and Solar Probe (SP)), was to be cost capped at $750 million. Believe it or not, this also included launch services on EELVs (and the Shuttle for EO), RTG power sources, development of X2000 enabling technologies (which turned out to be vaporware), procurement of science instruments, mission ops, data analysis, yada, yada, yada. Needless to say, OP/SP turned out to be a total fiasco that led to EO being spun off into a separate JPL-led effort, PKE initially getting axed and later brought back to life as a competitively-bid PKB mission, and SP getting axed and re-axed.

Posted by: BruceMoomaw Feb 10 2006, 02:38 AM

Don't forget that the new budget also axes all preliminary research for Mars Sample Return as well -- and the message communicated to the November COMPLEX meeting by Andy Dantzler and Doug McKutcheon had been that Europa Orbiter is definitely higher-priority than MSR for now, and indeed should fly over a decade earlier.

What happened is simply that the continuing attempt to keep Shuttle/ISS going has bled off huge amounts of money from EVERYTHING else -- not just from space science, but from Bush's own manned lunar program (and his tentative moves toward a manned Mars program, which have now been totally eliminated). He wouldn't have done that unless he had been forced to do it.

I was, however, wrong in saying that that Nov. 21 Washington Post article ( http://www.washingtonpost.com/wp-dyn/content/article/2005/11/23/AR2005112301970_pf.html ) said that unnamed Congressional leaders were forcing him to do it. The actual passage is:

"Several sources confirmed that the budget office in the early negotiations proposed stopping shuttle flights altogether. 'It sucks money out of the budget, and it's a dead-end program,' one source said.

"But 'that argument's over,' another source said. 'The political side of the White House said, "We're keeping it." If you kill the shuttle right now, it will be heavy lifting for your foreign policy because of the international obligations' around the space station."

However, that argument -- as Jeffrey Bell points out -- is utter twaddle; we could end the Shuttle/ISS program much more cheaply and cost-effectively by simply repaying our "partners" for their wasted money, especially since they themselves are getting increasing local pressure about flushing money down the ISS rathole. Something else happened -- and the single most likely cause is indeed pressure from Congressional leaders. Specifically, Texan Congressional leaders, since Texas relies specifically on the manned part of the NASA programs, while Florida and the other states could adjust much more easily to NASA spending that was reoriented toward unmanned programs. Feel free to fill in the gaps.



"

Posted by: BruceMoomaw Feb 10 2006, 02:44 AM

Also, historically, note that Captain Crazy's proposals for Mars Sample Return were even loonier than his proposals for OP/SP -- MSR missions starting in 2003, at $500 million per flight -- and COMPLEX, I shudder to report, found that program entirely plausible in a review in November 1998:
http://www7.nationalacademies.org/ssb/marsarchmenu.html

Well, they were only 21 years and $1.5 billion off.

Posted by: BruceMoomaw Feb 10 2006, 03:28 AM

A bit more on Bugsy DeLay's possible hand in all of this at:
http://www.hillnews.com/thehill/export/TheHill/News/Frontpage/020806/news2.html

As I say, he knows where all the bodies are buried.

Posted by: vexgizmo Feb 11 2006, 12:48 AM

A few reality checks here:

* I don't see Mars and Europa in competition, but if they are, I believe that Mars is not being shortchanged any in the mission department lately.

* X2000 successfully produced radiation-hard components, including components flown on Deep Impact. That investment is now awaiting a Europa mission to fly.


* COMPLEX typically reviews the architecture, not the costs.

Posted by: AlexBlackwell Feb 11 2006, 01:04 AM

Actually, I don't think it's a question of which target is being "shortchanged," and I think it's obvious that Europa is getting the shaft, rather it's which target is likelier to convince the politicians (both administration and congressional) to fund a Flagship-class exploration mission, IMO. If one operates under the assumption that only one such mission can be flown per decade, then, I would think, Mars and Europa are indeed in competition, at least in the short term.


Thanks, I wasn't aware of that. BTW, is there is a list somewhere of other realized X2000 products?

Posted by: BruceMoomaw Feb 11 2006, 02:02 AM

There's a nice summary of them (and the remaining problems) on the second page of an LPSC abstract co-authored by none other than Bob Pappalardo:

http://www.lpi.usra.edu/meetings/lpsc2006/pdf/1459.pdf

Posted by: BruceMoomaw Feb 11 2006, 02:08 AM

Where Flagship missions are concerned, NASA's original plan was to fly one per decade to a non-Martian target in addition to its separate Mars program.

Even within its hoped-for yearly funding for the Mars Program alone, however, NASA had been having trouble fitting MSR into the Mars schedule -- which is why they ended up bumping it all the way to 2024. About a billion dollars worth of its total estimated cost (now roughly $4 billion) must be poured into preliminary R&D starting a decade or more before launch.

Posted by: vexgizmo Apr 5 2006, 04:34 AM

http://www.washingtonpost.com/wp-dyn/content/article/2006/04/01/AR2006040100022_pf.html

Is NASA in Outer Space?
Not After a Surprise Round of Budget Cuts

By Michael Benson
Washington Post
Sunday, April 2, 2006
page B02
© 2006 The Washington Post Company

Posted by: The Messenger Apr 5 2006, 04:48 AM

In her NOVA interview, Carolyn Porco made it clear she would prefer to forgo Europa and take another stab at Enceladus.

As fascinating as Saturn is, I would prefer a fully-loaded Jovian mission first. There is much to learn.

Posted by: mcaplinger Apr 5 2006, 05:50 AM

Feel free to list those components; I'm extremely skeptical that any of the X2000 components ended up being megarad hard if they ever saw silicon at all. See http://centauri.larc.nasa.gov/outerplanets/Dscr_X2000.pdf for what these looked like for the first EO. The microcontroller was abandoned; the NVM slice never existed at anything like the hardness levels intended; and if the DC-DC converter was ever developed I've not heard of it. So just what are you referring to?

Posted by: Jeff7 Apr 6 2006, 12:36 AM

The coloration on the cracks of Europa is especially interesting to me. Far-fetched theory, but perhaps some sort of algae that turns brown after exposure to UV radiation?
More likely just some chemical oozing up from below, but who knows.

I guess the benefit of Enceladus is that the water's just spewing out into space from open cracks. Europa's got a helluva thick crispy crust protecting its water.

Posted by: dvandorn Apr 6 2006, 02:21 AM

You know, that's a good point -- Enceladus has geysers and Europa does not, at least not at present.

And yet, Europa's cratering record shows that its surface has been reworked pretty extensively over time -- there just isn't anything like the crater count that you find on, say, Callisto or portions of Ganymede.

On Enceladus, it's pretty obvious that the resurfacing is happening via the geyser activity. Older, more rugged terrain is being buried in massive "snowfalls" on Enceladus.

But on Europa, the relatively young surface isn't simply a visually homogenous covering layer of snow. It is a very complexly cracked surface that appears to have, at least at some pont, been a pretty thin covering over a large liquid ocean. As I understand it, it's hard to explain the cycloidal (I think that's the term) cracks if the ice layer has always been kilometers-thick.

But the Europan resurfacing *appears* to have had everything to do with repeated release of liquid water onto the surface and nothing to do with plume-deposited ice crystals. All slosh, no whoosh.

So, does this mean that Europa hasn't really seen geyser activity in the geologically recent past (i.e., since its last major resurfacing)?

And if so, what does the lack of such eruptions tell us about Europa?

-the other Doug

Posted by: ljk4-1 Apr 6 2006, 03:17 AM

Rule 3.5 - un-needed quote removed - Doug

I could have sworn there was an article in a circa 1980 issue of Sky & Telescope
magazine that showed what might have been a plume on Europa. Does anyone
have the details/image?

Posted by: BruceMoomaw Apr 6 2006, 03:29 AM

There was some speculation by one researcher that that photo MIGHT show a plume -- but later study did not bear him out. Cynthia Phillips, in particular, has been going over every damn spacecraft photo of Europa ever taken looking either for plumes, or any signs at all of visible changes in surface features -- and, so far, she hasn't found a thing.

The evidence continues to grow that Europa undergoes cycles of varying levels of tidal heating, over periods of 50-100 million years, as it and the other Galilean moons slowly shift their precise orbital relationships -- and that at the moment it is in one of its cool periods, with a thicker crust and thus no cracks or vents punching through the ice (but with solid diapirs of warm ice, perhaps accompanied by local pockets of briny meltwater, slowly creeping up through the current thick ice layer to produce the "lenticulae" and chaotic terrain, which seem to exist on the fresher areas of Europa's crust).

Posted by: tedstryk Apr 6 2006, 10:18 AM

I remember that. The problem was that it was a single pixel in a lone opnav frame. Therefore, the probability of it being noise, especially given that there were no other frames showing it, is too high to reach any conclusions.

Posted by: vexgizmo Apr 6 2006, 02:00 PM

Have a careful read of the Enceladus Science papers (specifically Porco et al vs. Spencer et al.) and you will see that the evidence for water is equivocal, and arguably circular. The prime piece of evidence for liquid water (Porco et al) is the inferred high ice/vapor ratio of the plume (top of p. 1398). This is inferred from scattering models and assumptions of plume particle sizes and argued unlikelihood of particle entrainment in sublimating gas (briefly explained in note 30). Should we hang our conclusions and exploration strategies on that? Instead (Spencer et al), the fractures of Enceladus may simply expose warm (T ~ 180K) ice which sublimates like a comet (p. 1405). Show me the water. (Perhaps discussion appropriate to a different thread.)

Posted by: volcanopele Apr 6 2006, 06:12 PM

That does make it helpful in the sense you don't have to drill down as much (and the fact that no one really cares about Europa ). So the material you want is much more accessable. However, if you want to land, there isn't much choice on where you can land as only a very small percentage of the surface has a resonably access water body beneath it (assuming of course that a sub-surface body of liquid water generates the plumes). Europa would presumably have a far greater number of acceptable landing sites.

But that still leaves the problem that no one cares about Europa.

Okay, I'll stop messing with vexgizmo now.

Posted by: JRehling Apr 6 2006, 07:09 PM

Is the number of sites a big problem? One is enough, as long as it's not so small as to be hard to target.

I think a bigger problem, even in the best case, the engineering task becomes difficult/uncertain:

Supposing Enceladus does have a pocket of H2O "magma" that spritzes out of a few cracks, the exploration strategy isn't totally clear. There must be some artesian pressure working to force that water out, and whether you want to go in via the existing aperatures or make your own, I don't see how that would work. I see a lander getting fatally blasted by a rocket-fast stream of H2O coming the other way. Maybe we should send two and have one take video of the other one. But that doesn't get us a submarine in that lake.

Or maybe a lander could study from nearby the gush of vapor/ice from a vent, but then what's the point of being on the surface at all?

Even if the optimists are right (and I think they are), I don't see the exploration strategy.

Maybe the way to go is to identify a place where the ice is a desired thickness, like 100 m, and then use a melt-down approach that counts on the tunnel re-freezing behind the probe. Then when it finally taps into the high-pressure soda water, it'll have nowhere to get rocketed back into except the ice at its butt end.

That mission would require a precursor of some sort.

I'd say we might just want to put a lander or even the very same class of lander onto both Enceladus and Europa in the locales of most likely water access and perform a Viking-equivalent mission analyzing the ice for nonice content, and using seismic/sonar means to investigate local ice depth/structure.

It seems like the superset of options would be:

Europa Orbiter
Europa Icepick Sample Return
Europa Surface Lander
Europa Subsurface/Submarine Mission

Enceladus Orbiter
Enceladus Plume FlyThrough Sample Return
Enceladus Surface Lander
Enceladus Submarine Mission

Enceladus science needs to age like a wine before the sense of those missions can be evaluated. Europa Orbiter is clearly a need, even if it's not clear that it's the top need. The two Surface Landers could merit identical design. I can sense Europaists getting itchy at the idea that the two worlds getting anything like a unified approach, but if the two worlds both have the water endgame feasible, then I think the plans ought to converge. On the other hand, we may have an Enceladus without actual liquid... or we might have Europa with a crust so thick as to indefinitely discourage access to the ocean. It would seem that Europa has the advantage of getting the next move, but Enceladus is more likely to get to the endgame this century.

Posted by: BruceMoomaw Apr 6 2006, 07:41 PM

I suggest that, since most of the water spewed off Enceladus' plumes immediately falls back onto the moon, the logical course is to touch down a modest distance from the plumes, just collect the falling snow, and then periodically melt, filter and analyze it for organic remains.

After all, even if (as Bob Pappalardo suggests) the plumes may just be due to ice sublimating off the surface of Enceladus, when that surface is heated from underneath by warm liquid water, you're going to get a conveyor-belt recycling over geological time -- the snow will reaccumulate on top of the ice near the plumes, and its weight will cause more of the ice on the bottom layer to sink down to depths where it in turn will be melted before later being refrozen into the bottom of the ice layer. And since Saturn, unlike Jupiter, does not have an intense radiation environment, there's a good chance that any biological or prebiological remains in the warm liquid water will survive for a long time on the surface after having been frozen into the bottom ice, slowly carried upwards by the solid-state convection in the ice, and then expelled onto the surface. (This, after all, is precisely why we're hoping for frozen biological remains in Europa's near-surface ice, once you dig down the relatively short distance below its radiation-damaged upper layer. In the case of Enceladus, the sampling is easier. And if Titan's cryovolcanism is as strong as it currently appears likely to be, a similar search for frozen biological remains in the surface ice from its probable subsurface ocean also makes sense -- and, in fact, the instrumentation for the suggested Titan Organics Explorer WOULD look for chirality in any surface organics that it finds.)

Clearly the first step is to try to (1) get more detailed information on the trace components in Enceladus' plumes; and (2) try to get a measurement of the precise surface temperature at the central source of the plumes. Which, of course, is prcisely what Cassini will be trying to do in its super-low 2008 flyby, which is why its controllers have decided to run that risk. (Notice how Enceladus, so far, has been the ONLY thing found in the Saturn system that has made Cassini's controllers change their original mission plan?) Only then -- and only after Cassini has also told us a lot more about Titan's global surface layout -- will we be able to make any reasonable judgement as to what to do about these three worlds, and the order in which we should do it.

Posted by: Bob Shaw Apr 6 2006, 07:50 PM

If Enceladus does indeed have a conveyor-belt snow recycling system, then it might also be that we'd find analogous sites to the Antarctic locations where meteorites fetch up. By sampling along such a 'shoreline' where fresh snow gets trapped and sublimates away, we might have access to the greatest repository of objects from other worlds anywhere we've yet found!

Bob Shaw

Posted by: BruceMoomaw Apr 7 2006, 01:13 AM

You misunderstand me. Once the snow lands a certain distance away from the warm regions where the ejection of water vapor occurs (either by direct geysers or by sublimation of ice from the top surface of the warm regions), it stays in place permanently. And the only debris carried up with the water, even if geysering occurs, is possible rocky material from Enceladus' interior -- and then it won't be kicked a long way from the geysers unless it's quite fine material. (If the plumes consist of water vapor just sublimating off a warm ice surface, no other material at all will be spread farther by the plumes, except of course for the trace gases mixed with the water vapor -- but the glacially slow convective "conveyor belt" of warm ice creeping upward in the central warm region, and descending again in the cooler peripheral regions where the snow is accumulating, might carry some rocky debris from the interior up to the surface in the plume regions.)

In any case, those trace gases that get expelled along with the water vapor explain the frozen CO2 and other "light organics" which the VIMS HAS seen spread on the surface for some distance from the vents, along the Tiger Stripes -- and getting a better look at the composition of those other substances with the VIMS must be yet another urgent goal of the coming super-close 2008 Enceladus flyby. (Bob Pappalardo, by the way, obligingly sent me copies of the "Science" articles on the VIMS and mass spectrometer findings, which I'm reviewing right now and will report on later.) If it turns out that the plumes ARE just due to vapor boiling gently off the surface of a quite wide area of relatively warm ice, then it would almost certainly be safe for a lander to touch down right in the middle of the plume region -- and analyze the ice right there to see what else was oozing up from Enceladus' interior along with the warm ice.

Posted by: JamesFox Apr 7 2006, 01:23 AM

I just have to ask this question: When it comes to Scientific information, would a mission to Enceladus provide more information than a mission to Europa assuming no life, or complex organics, are found?

I know the liquid water = life argument is trotted out with regularity, but that is still pretty uncertain. At least a Europa Orbiter, or some analagous mission, would provide us with lots of extra information on the Galilean Moons, but this proposed Enceladus mission seems totally focused on life,life,life. If the life does not show up, then it would seem that the mission would be mostly a waste. It seems a bit risky to me.

I would hope that the people at NASA can conceive that -there may be liquid water there-, and -we may get clues to the formation of the solar system- are not the only good reasons to send out space probes. Io, for example, is a fascinating place. There is also a certain satisfaction is getting the first good images of an object that was previously just a dot or a smudge, at least to me. That's pure exploration.

So what I am saying is that I find throwing away a mission that will return valuable, non-search-for-life science , in return for a mission with a remote chance of hitting the jackpot, rather reckless.

Posted by: nprev Apr 7 2006, 05:26 AM

I must respectfully disagree with you, James. Although finding life on Enceladus via a lander mission would of course be the scientific coup of Western civilization, in situ observation of the plume processes and associated chemistry would still be valuable in its own right, and certainly enlightening in a wide variety of ways.

Consider: We don't really understand why Enceladus is even active at all at this time. Pure tidal influences seem inadequate; is there something unique about the moon's geochemistry? This is a valid research question with profound implications for the formation of the Saturnian system that alone would justify a lander.

By comparison, Europa does not seem to demonstrate any recent cryovulcanism (although I acknowledge that the Galileo dataset may not have been sufficient to rule it out completely) despite the fact that it's much more massive than Enceladus and also exposed to significantly greater tidal stress.

Therefore, if forced to choose (as we must given the newly austere budget environment), it seems rational to study the more geologically active target in detail first. Finding life would be nice, but it cannot be the entire rationale for such high-risk missions.

Posted by: PhilHorzempa Apr 17 2006, 09:45 PM

[size=2]


Back to the subject of the Europa Orbiter, I think that we need to call
Griffin on his remarks last week at the NSS (National Space Symposium).
He suggested that we wait 10 years until the heavy-lift CLV and CaLV
are available. Then, NASA could fly a Jumbo mission to Europa.

This is the same old trick that Goldin, and company, tried in 2000 when
NASA wanted to cancel a mission to Pluto. At that time, it was suggested
that we wait until an advanced nuclear ion propulsion system becomes available.
Then we could launch a Pluto probe on a really fast trip to that planet.
Fortunately, Congress saw through the "smoke-and-mirrors" and added
funds to NASA's budget for the New Horizons probe. As the UMSF community
can see in another post on this site, the advanced propulsion effort, Project
Prometheus, has been cancelled.

I hope that Congress is not tempted to believe that there is merit in Griffin's
suggestions at the NSS. We need to reject Griffin's siren call to wait, and
instead get on with a mission to Europa using technology already in hand.


Another Phil

Posted by: Cugel Apr 18 2006, 08:33 AM

As if flying a scientific mission on a man-rated mammoth booster would ever be an option. How many unmanned probes did we launch on the Saturn boosters? Even when they they were ordered and payed for, they were send to a museum rather than to Jupiter or Saturn. Mr. Griffin's suggestions are starting to sound pretty desperate, if you ask me. I still hope ESA can play a leading role in a Europa orbiter, it seems such a logical next step.

Posted by: djellison Apr 18 2006, 09:05 AM

Pluto was a special case - the atmosphere is a ticking bomb waiting to go bye bye - we needed to get there by X to have a good chance of investigating it before it froze out.

I agree that Enc and Eur can 'wait' as it were. But only for financial reasons (i.e. we can't afford them at the moment) however - there is no need or requirement for the new heavy LV for those missions. If what you're building busts an Atlas V Heavy, Delta IV Heavy or any other LV mass budget, then you need to be more creative with your mission - slingshots, ion prop - whatever it takes.

Doug

Doug

Posted by: ugordan Apr 18 2006, 09:12 AM

Do you really think ESA can afford funding such a grand mission? From what I gather, Venus Express is their last planetary mission (for the time being) and they're now shifting towards astronomical observatories.
Any involvement in EO would likely be in the form of a joint NASA/ESA mission and I don't know how likely that is given the current state of NASA and its unmanned space exploration. ESA already was once in a position of rescuing a mission from being cancelled (Cassini) and it's questionable whether they are willing to take the risk again and see the U.S. folks bail out on them halfway through the development phase. IMHO, NASA (arguably not due its own fault) just currently can't be taken as a reliable partner.

Posted by: ugordan Apr 18 2006, 09:29 AM

Saturn V was never a launch vehicle that went into serial production. Contracts were made to build 15 or so of them and then the industrial infrastructure and manpower was laid off. In the end they winded up with a couple of surplus ones and used one to lift Skylab as it was one of the uses a Saturn could have been used as a heavy lift booster. It was much too expensive and useless to continue production because their capability was pretty much overkill once the moon race ended.
Even today, think about its capability - IIRC 30 metric tons to Earth escape velocity. Building a probe that heavy and capable would probably take billions (along with the cost of the vehicle itself) and its obvious these days one can't get even a measly billion for a flagship mission. You'd have an ultra-heavy booster that the market just doesn't need. In that light, it'll be interesting to see where Delta IV Heavy will end up.

Posted by: edstrick Apr 18 2006, 10:29 AM

The Skylab booster was the Apollo 20 Saturn 5. The abandoned flight vehicles were the boosters for 18 and 19. However, there are 3 Saturn 5's on display!

All of them incorporate parts from something that LOOKS like a Saturn 5 but was never a flight vehicle: the "Facilities checkout vehicle"... used to test VAB/Crawler/Launch-Umbical Tower/Pad equipment, including fueling exercises. But it didn't have real engines or lots of other stuff.

Things are a bit more complicated than that IRL, but you'd need to read the exhaustively detailed new book on Saturn 5 to find out.

Posted by: Rakhir Apr 18 2006, 11:46 AM

ExoMars ?
Preliminary design study was launched a couple of months ago.

Posted by: Cugel Apr 18 2006, 01:31 PM

So, if it's not NASA (too much vision), not Russia (never been interested) and not ESA (ExoMars will keep them busy)... who is going to take us back to Europa/Titan/Enceladus?

BTW, I thought I heard something like using a Saturn (I or V, don't remember) for launching a Viking style mission to Mars or even a Voyager type mission to the outer planets. Is there any truth in that?

Posted by: ugordan Apr 18 2006, 01:46 PM

Well, apparently no one. Not in the foreseeable future, anyway...


Sounds like another one of those ideas that were never meant to be. Like Prometheus & Jupiter Icy Moons Orbiter.

Posted by: Mariner9 Apr 18 2006, 03:45 PM

Cugel,

There were plans in the 1960s for a mission to land on Mars called... beleive it or not ... Voyager.
Those missions, I think planned to start in 1973, would have used Saturn launch vehicles. One plan I can recall even had a dual launch on top of a Saturn V !!!!!

Well, Voyager got canned due to the amazing costs (I think). Born out of the ashes was a slimmed down mission called Viking. Slimmed down, that is, at a then staggering final cost of one billion dollars (roughly 4 bilion today, I think).


A few years later, the TOPS mission - Thermoelectric Outer Planets Spacecraft - was also canceled due to the high costs. It was replaced by a slimmed down mission called Mariner Jupiter-Saturn. There are many stories of the ressurection of the mission.... one version has it that the OMB was actually surprised that TOPS was killed since they had bought into the idea of the economy of multiple spacecraft of identical design visiting so many new planets all in one mission. Thus, they were very receptive to a lower cost mission that addressed many of the same goals. Another point often made was that the very name Mariner implied design inheritance and continuation of a very sucessful program. Recall that Mariners were the first to Venus, Mars, and Mercury.

Several years into the program, I think people decided that since Viking was a snazzier name than something like Mariner Mars 75 would have been... why not do the same with mariner Jupiter-Saturn? Eventually, much to everyone's surprise, NASA came up with Voyager, in spite of the fact that the name was linked with a politically dead project.

I'm not sure what this portends for the future. I can't think how you could name a future mission JIMO for example... unless the acronym was changed to "JIMO - Justification for Incredible Monetary Overruns".

Posted by: ljk4-1 Apr 18 2006, 06:35 PM

This online NASA book has the history plus images of the original Voyager mission
plans for landing probes on Mars:

http://www.hq.nasa.gov/office/pao/History/SP-4212/on-mars.html

And check out these documents:

http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19660020129_1966020129.pdf

http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19660020104_1966020104.pdf

http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19850024813_1985024813.pdf

And - Conceptual Design Studies of an Advanced Mariner Spacecraft (all but Volume 2):

http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19660005976_1966005976.pdf

http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19660005978_1966005978.pdf

http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19660005979_1966005979.pdf

http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19660005980_1966005980.pdf

Posted by: Cugel Apr 18 2006, 07:47 PM

Thanks! Apparently, I got it mixed up.
Very interesting links!

Posted by: BruceMoomaw Apr 28 2006, 09:33 AM

There are some more details at http://www.lpi.usra.edu/meetings/lpsc2006/pdf/1459.pdf :

"Key radiation areas include:

"(1) Flight Computer - A reliable, powerful, radiation tolerant flight computer (RAD750) has now been demonstrated in flight (e.g. Deep Impact and MRO), with over 100 ordered by a number of other customers.

"(2) Electronics – ASIC design and development are complete and are ready for flight qualification, and many new radiation tolerant electronic parts have been developed and are now available for use

"(3) Memory and Communication – A remaining problem in the radiation area is the development of radiation hard memory for science data. However, existing radiation hard SRAM technologies can be used to provide sufficient science capability when combined with operational scenarios and high rate downlink capabilities (< 300 kbps) made possible by the increased mass and power margins."


Regarding the biosterilization of Europa Orbiter, I may or may not have mentioned that the current strategy is to heat-sterilize all portions of the craft's avionics that are shielded from Jupiter's radiation, while just relying on that radiation to sterilize all exposed components of the craft. Those components will just undergo alcohol cleaning et al.

Posted by: PhilHorzempa May 6 2006, 01:42 AM

Here is an interesting new twist to the Europa Orbiter and SIM sagas. As posted on
NASA Watch, a letter from Rep. Wolf appears to be directing NASA to alter their
FY06 Operating Plan so that NASA obeys Congress' specific instructions to start
funding the Europa Orbiter project, and to maintain proper funding for SIM.

Doesn't this mean that Mike Griffin has now been warned that he is in danger
of breaking the law unless he immediately takes steps to comply with Congress'
directions?

You can check out the letter at this site.

http://images.spaceref.com/news/2006/Wolf.Op.Plan.04.07.06.pdf



Another Phil

Posted by: BruceMoomaw May 6 2006, 05:19 AM

Actually, it isn't that dramatic. Wolf simply demands that NASA add another $28 million to aeronautics research and $30 million to the Mars program (with no specifications on how it should be spent), and that it "continue funding for Terrestrial Planet Finder [not SIM], and...begin planning for a mission to Europa in fiscal year 2006...With the exception of these significant deviations from Congressional direction, the Commitee has no objection to the allocations of funding proposed in your letter."

Besides the vagueness on just what that $30 million more for Mars is supposed to be for, Wolf doesn't give any order how much NASA should spend this year on Europa Orbiter planning (50 cents, maybe?) And I've said before that I think Terrestrial Planet Finder spending, like Mars Sample Return planning, can be safely delayed for several years until we have a better idea just what general kind of mission we actually want to fly. (In the case of TPF, there are two completely different possible mission concepts; and which of them should be chosen depends very strictly on Kepler's census of how common Earthlike planets really are -- something we won't have until 2012 at the earliest.) Nor does Wolf tell us what projects he thinks that funding should be pulled out of.

Posted by: remcook May 6 2006, 08:19 PM

Here's a bit from Emily's write-up of the OPAG meeting:
http://planetary.org/blog/article/00000567/

my question: how does the "planetary protection" work for an Europa orbiter? Do they save enough fuel to crash it into Jupiter (that sounds like a lot of delta-V, but perhaps it's not that bad in the multi-body system. Any ideas?). Or do they keep the spacecraft as clean as they would for an impactor or lander? (I guess not, judging from the comment about the old mission).

Posted by: elakdawalla May 6 2006, 10:32 PM

I'll put in here the full sales pitch comparison from Karla Clark:

EO = Europa Orbiter (cancelled 2001)
EE = Europa Explorer (current idea from JPL)

Instrument mass: EO: 27 kg; EE: 180 kg
Instrument power: EO: 27 W; EE: 100 W
Number of instruments: EO: 4; EE: 10
Lander: EO: not possible; EE: 340 kg mass available (which had some audience members shaking their heads, as a chunk of that will be taken up in margin)
Duration: EO: 30 days; EE: 90 days plus
Data return: EO: 100 Gb; EE 3000 Gb
Extended mission possible: EO: none; EE: 125 days.

--Emily

Posted by: elakdawalla May 6 2006, 11:09 PM

Bob Pappalardo just answered part of this question in his presentation here at ISDC. The interior of the spacecraft -- instruments and electronics -- are sterilized. The outside can't be because it's, well, outside; at some point it contacts Earth stuff. Bob said that the radiation environment is so intense at Europa's orbit that the outside will be quite completely cooked after it gets into Eruopa orbit. Now -- that doesn't explain why the original Europa Orbiter proposal ran in to problems. Still need an answer to that part of the question.

--Emily

Posted by: BruceMoomaw May 7 2006, 01:19 AM

That's what was said at the Europa Focus Group, too. (I have no idea whether "Astronomy" will EVER get around to printing my small Web article on that meeting, although they did pay me for it -- and even if they do, I doubt it contains much by now that Emily hasn't since reported on her blogsite anyway. Grrrr.)

I don't know why they've eased up on sterilization requirements -- it may just be that they decided, after reexamination, that the initial ones were simply too costly and unjustified. I hope NASA isn't cutting corners on this; as the 2000 SSB report ( http://www7.nationalacademies.org/ssb/europamenu.html ) pointed out , if you get a single viable germ into Europa's ocean it could spread all the way around that world almost immediately -- which is not the case with Mars.

Two other notes about the redesigned Europa Orbiter (now rechristened "Europa Explorer", as Bob Pappalardo recently indignantly reminded me). First, (as Emily has also now pointed out), it now has a large gimballed, swivellable high-gain antenna, allowing it to take data and relay it back to Earth simultaneously and thus vastly increase its total data return. Second, besides the decision to utilize Earth and/or Venus gravity assists to send it to Jupiter -- which by itself utterly revolutionized the mission design by doubling or tripling the spacecraft's possible mass -- there's been another stroke of luck: the latest reanalyses of Galileo's radiation measurements indicate that the expected dose for a Europa orbiter is only half that previously estimated, allowing them to economize greatly on radiation shielding while still tripling the craft's previous 1-month design life in Europa orbit.

Posted by: mcaplinger May 7 2006, 06:32 AM

While BAE's roadmap claims they are working on a megarad-hard RAD750, the ones they've delivered are only rated to 100 krad, which is at least 3x too soft for the radiation environment we were working to for EO. Maybe they've moved that bar now.

There have been no dramatic technology breakthroughs. Any claim that a Europa orbiter has been enabled by such is simply marketing hype.

Posted by: BruceMoomaw May 8 2006, 10:20 AM

I just saw Emily's entry on the second day of the new OPAG meeting, which was devoted to discussions as to how to try to deal with NASA's space-science spending problems ( http://www.planetary.org/blog/article/00000573/ ). Cripes! In retrospect, it was an understatement for me to say earlier that space scientists have now hit the "Raft of the Medusa" stage -- they've now gone far beyond that, and are now eating not only each other but themselves. (They are, apparently, also now considering trying to save Europa Orbiter by cancelling not just the next Discovery and New Frontiers selections, but also the 2011 Mars Scout.)

Posted by: JRehling May 8 2006, 08:35 PM

If the radiation environment is less hostile than previously estimated, Galileo's long life can be seen in a new light.

Posted by: PhilHorzempa May 22 2006, 02:08 AM

As we wait for NASA to come to their senses and start work on the Europa
Orbiter, here is an image to whet our appetites. According to NASA, it is the
highest resolution image of Europa obtained by Galileo. This image is from
Galileo's 12th orbit around Jupiter and was recorded on December 16, 1997.

I've always liked this image as it reminds one of the view you would
get looking out of an airplane window (I know that Europa has no atmosphere.).
I consider it in the same class as the famous Lunar Orbiter 2 oblique photo
of the crater Copernicus obtained about 30 years before the Europa image.

It's been over 8 years since the Europa photo was taken. How many more years
before we get back - 8? 10? 15?

Here is the Europa photo

http://photojournal.jpl.nasa.gov/jpeg/PIA01180.jpg


Here is the Copernicus photo

http://upload.wikimedia.org/wikipedia/en/2/2d/Lo2_h162_3.gif

Posted by: Decepticon May 22 2006, 10:20 PM

At the rate we are going I hope to see any probe to Europa. I'm 30 now.


I was hoping for a Subsurface Probe buy the time I was retired.

Posted by: BruceMoomaw May 23 2006, 01:25 AM

There was a little commentary on that photo at the February "Europa Focus Group" meeting -- specifically, that while it shows what seem to be ridges with quite dramatic slopes, it doesn't seem to show any large crevasses (and its resolution should be high enough to see them if they're there). Also note the total absence of small craters.

Of course, the tendency of dark material to slide to the bottom of slopes on the Galilean icy moons may be exaggerating the apparent roughness of the ridges as well.

Posted by: PhilHorzempa May 23 2006, 01:50 AM

attachments removed - they were linked to just a few posts above, no need, use or benefit to attaching them to a post.

Posted by: vexgizmo May 26 2006, 07:19 AM

I always regret that the highest-resolution Europa press release photos were only half-released soon after the Galileo image data first hit the ground, but never updated with full versions of the photos after the 2nd pass through the spacecraft's tape recorder. Here is the full photo, rotated and with a stretch applied. Mind the gap.

Posted by: mchan May 26 2006, 08:02 AM

Wow, the added context puts the view into perspective. I recall seeing the left half image separately before, but did not associate it with the right half image. I gather you "mind the gap" comment is referring to the data dropout, but I also find "gap" going from side to side striking, particularly in revealing the cross sections on the right side.

Thanks for posting the image!

Posted by: BruceMoomaw May 26 2006, 12:24 PM

Has anybody ever done a photometric analysis of this image to try to determine how much of the dark areas is due to genuine sun-angle shadowing, and how much is due to dark-albedo material in the lower-altitude places?

Posted by: algorimancer May 26 2006, 01:00 PM

I too had also only seen the lower quality half-image previously. Wow, indeed. There's just all sorts of neat stuff going on in there... I'd love to spend a few days hiking around the area. If I'm not mistaken, there are even hints of layering in some of the tilted slabs, which could probably tell us something interesting about the history of the ice.

Posted by: algorimancer May 26 2006, 01:49 PM

Noticed that the slab at the bottom left fit neatly into the mid-left section. Like putting a jigsaw puzzle together

So all that blocky terrain in between came from elsewhere. Cool

Posted by: Cugel May 26 2006, 02:35 PM

I wonder if the slabs on the top and bottom drifted apart and the blocky terrain welded up from below. That blocky piece of terrain has a different texture all together, sort of chaotic, where the two slabs are much more grooved.

Posted by: monitorlizard May 27 2006, 12:38 AM

Remember the Voyager days, when Europa was touted as being "the smoothest object in the solar
system"? Now, everybody talks about how rough the surface is for a landing !

Posted by: vexgizmo Jun 16 2006, 04:16 AM

For those Europaphiles who might have missed this, from the Planetary Society. Additional info is on Emily's TPS blog. The House Subcommittee, at least, wants to see a Europa new start.

http://www.planetary.org/about/press/releases/2006/0614_House_Subcommittee_Helps_Save_Our.html

June 14, 2006

House Subcommittee Helps Save Our Science

Pasadena, CA, — The fiscal year 2007 budget proposed by the Administration for NASA threatens to end a dazzling era of planetary exploration. Today, the House Appropriations Subcommittee on Science, the Departments of State, Justice, and Commerce, and Related Agencies marked-up the NASA budget, prior to sending the budget to full Committee.

The subcommittee today approved a budget of $16.7 billion, $100 million less than that requested by the Administration. But, it restored $75 million (out of $330 million) of the funding that the Administration had cut from space science plans. ...

Especially noteworthy was $15 million directed for a mission to explore Europa, the icy moon of Jupiter, with a subsurface ocean that is considered by many scientists as a possible habitat for life. This had been cut out of the plan by the Administration, and The Planetary Society vigorously campaigned for its reinstatement. Rep. John Culberson (R-TX) has been a strong supporter of this mission. Funding for the Terrestrial Planet Finder mission was also provided, another mission that the Society strongly supported.