Planetary scientist says: Focus on Europa
By Tony Fitzpatrick
Washington University in St. Louis News & Information
February 7, 2007

I think the scientific community most focus on one target (Europa, Titan, Enceladus) to have a chance to get the funding for one outer planets flagship mission. They won't get two, I am afraid.

My priorities:

- Flagship to Europa or to all Jupiter moons (like Galileo)
- New Frontiers mission 3 to Titan or Enceladus (no lander), maybe with ESA (with lander) and Cassini extended
- Flagship to Neptune sometimes arround 2025
- next Discovery mission to Venus

Analyst

Maybe it's different with other screen settings, but this is how my browser displays the heading for the (previous) latest post in this thread, on the UMSF main page:

Click to view attachment

Somehow it brings to mind a quite different idea...

"When Galileo's antenna didn't open, ..."

"When Mars Polar Lander went splat, ..."

And a party game. Invent another abbreviated topic title. Hilarity ensues.

Phil

The other being "Rover driver says: Oh S..."

[...]

...yes, some of these abbreviated titles have also given me pause on occasion...I always check out the thread, though!

I agree with Analyst; seems like it might be time to focus outer-system exploration in light of new budget constraints. Question here is whether Europa is both the most scientifically interesting & comparatively less risky target if we have to put most of our eggs in one basket.

One thing that's really nice about Titan & Enceladus is the relatively benign radiation environment...seems like a flagship-class mission to either of these would be more survivable & less expensive to build for that reason alone, though that might be traded off for increased booster & long-term cruise mission management costs.

I suggest two big probes of which both include an orbiter and a lander. The first one to be Jupiter orbiter/ short living Europa lander, the second one - Neptune orbiter/ short living Triton lander. This is the cheapest alternative IMO. Other ideas:

1. Airplane, or several baloons for Titan
2. Several small penetrators for Europa. Good idea if we want to find out what's below the surface.
3. Saturn atmospheric probe.

We can find some more ....like Phil and Doug,

"Yesterday, 08:16 PM
In: Fire possible only on plane...
By: helvick"

I too would really love to see a mission to Europa.

One thing I wonder about Europa though - it has a pretty good shell of ice around it. Can this shield the ocean below from the radiation around Jupiter? Exactly what kind of radiation are we talking about?

I ask because one theoretical spaceship design I've seen to get astronauts to Mars would be a spherical ship, with a shell containing liquid water. This would serve as a shield against interplanetary radiation.
This is only theoretical, because such a ship, in order to be large enough to hold a crew and supplies, would be extremely massive, and nearly impossible to launch and even propel to Mars, much less have it return.

[...]

I think the seasons of each of the main targets may dictate which each mission should take place. For Europa, a mission can occur at any time since it has a very low axial tilt with respect to the ecliptic, and there is no polar region priority. For Titan, it would be best for a mission to reach Titan at or shortly before equinox so that 2 micron mapping coverage can be obtained for the entire satellite. For Enceladus, the best time would be at or shortly before southern summer solstice to get the best coverage possible of the south polar region.

Given this, here is a possible schedule:

Europa: Launch 2013-2014 Arrival: 2015-2016
Titan: Launch: 2018-2019 Arrival: 2025
Enceladus: Launch: 2025-2026 Arrival: 2032

Of course, add in some New Frontiers missions to Io...

I expect a lot of creativity to appear. Bruce Moomaw has pointed out that an Europa orbiter could do a number of Io flybies by using some of the mass margin for extra radiation shielding. The mission will also involve a number of Ganymede flybies.

Thanks for that link. That is indeed a very handy and well-written summary of the situation at Europa. I'm doing some Europa reading just in case the planners manage to resist the siren songs of Titan (but how could they?)

Volcanopele, I like your timetable. That means two big mission launches in quick succession. And why not! Where there's a will there's a way. We must demand BOTH the moons, at the best time to maximise the science. Given some of the things money gets spent on (not just in America) I see no reason to be timid about these entirely worthy, knowledge enriching, consciousness-raising, humanity-defining enterprises.

More from McKinnon, et al. A nice story from the St. Louis Post-Dispatch, plus a couple of nice graphics.

http://www.stltoday.com/stltoday/news/stor...9F?OpenDocument

"We think the ocean leaks onto the surface," said McKinnon, a planetary scientist at Washington University. "What does that tell us about the chemistry of the water that's down below? And the 64 billion dollar question is, could any of that stuff have the signature of life?"

I agree with you wholeheartedly, NG, but the sad fact of the matter is that due to numerous other present US government financial pressures and priority shifts (which we won't discuss due to forum rules), it's extremely unlikely in my opinion that there will be enough funding available for two or more outer-system Flagships anytime soon. In fact, we'll be really lucky to get even one funded, so that's why we'd better choose carefully...

On the other hand, this constraint may drive innovation as vjkane2000 noted. Two or more very capable Discovery-class missions may be preferable, and certainly would provide a more comprehensive science campaign.

I know that NASA currently looks like the only agency that could fly these missions, but this could change. I think we in Europe could be putting more pressure on our governments to step up our efforts in space, and who knows what China will come up with in another 10 years? This should be a global effort, with different technical and philosophical approaches enriching the mix, whilst maximising international co-operation where appropriate. I really think that the high profile of Cassini and its astounding results are changing the public mood. In Europe especially the sheer boldness of the Huygens landing and the novelty of watching live television from Mission Control in Europe (for the first time since Giotto, I think) has opened a few more minds to the possibilities. The laughable Pluto debacle of last year raised public awareness of the outer solar system enormously and will do nothing but good whan it comes to keeping New Horizons in the news. So, viewed narrowly as a NASA budget decision maybe its one moon only for now. But meanwhile, for the other, let's see what we can all do together.

Truly an excellent point, ngunn. Collaborative missions make more sense then ever these days, and Cassini/Huygens set the gold standard for this. Administratively, there should be (if there isn't already) a joint UMSF program planning office for ESA & NASA at least; would be great to include the UK & Russian space agencies & JAXA as well!

The Europeans have studied a mission that divides the Europa mission into two craft, a small Europa orbiter and a relay craft. If you expand on that idea, the number of science instruments that must be in Europa orbiter are fairly small -- the altimeter and the subsurface sounding radar come to mind. The second craft could be a very capable Jovian orbiter that does multiple flybies of the moons and could do the high resolution optical and spectral mapping. It could also serve as a relay for the Europan orbiter.

This approach to the mission would be ideal for international cooperation. One nation/set of nations could build one craft and the other the second craft. We could get what Galileo should have been but with modern instruments plus the unique science possible only from Europan orbit.

Jupiter's moon Europa should be NASA's next target, says ASU researcher
Public Release: 18-Feb-2007
2007 AAAS Annual Meeting

Looking for life on Jupiter's icy moon Europa
By Robert Sanders, Media Relations, UC Berkeley News
22 February 2007

[...]

Yeah...seems that way, all right. Has to be in part a reaction to new budget constraints here in the US, not sure if ESA is also getting pinched.

My idea of a Discovery-class mission that could conceivably run the gauntlet: A Jupiter orbiter (recycled, modified NH bus?) with a ridealong semi-hard lander that might have a simple surface imager, but more importantly could determine the conductivity of the local ice. Based on my experience with NOAA, you can learn a tremendous amount about ocean chemistry from measuring this simple property alone; this principle may also apply to Europa. (Better land it on the side opposite the direction of orbital motion, though, in order to minimize Io gunk!)

I do hope I live to see a lander put on Europa's surface. Even if we can't drill down to find liquid water, just examining some of those reddish deposits could yield some extraordinary information.

For those who may have missed it, there is some interesting supporting documentation available from the "Science rationale and mission strategies for the exploration of Europa and the Jupiter system" workshop held April 23-24, 2007, at the Space Research Institute in Graz, Austria.

See also this site, which gives more information on the ESA-NASA Working Group (ENWG) for the exploration of Europa and the Jovian System.

Interesting.... so their nominal mission scenario is to have a Jovian relay/science orbiter with a Europa orbiter (presumably supplied by NASA) attached at launch... conceivably, in an extended mission for the Jovian relay sat, it could be focused on Io...

I only have one basic question, but upon it unfortunately hangs the feasibility of any such mission.

How are you planning on dealing with the intense radiation environment at Io? It's not just a matter of using hardened circuitry -- CCDs in imagers, which have to have a visual path to what they image, will deteriorate quickly at Io. Everything not encased in massive (and I mean that word literally) shielding is going to fail very, very quickly in Ionian orbit.

Another issue is the fact that it takes continual maneuvering to remain in a stable orbit around Io, because of the pulls of Mother Jupiter and sister Galileans. But that's a minor issue compared to the raditation environment issue.

I agree, it sounds like exactly the kind of mission I'd like to see. But I really wonder if we have the technology to pull it off any time in the next 50 years.

-the other Doug

[...]

I was responding to a post by our new member, 3488, which suggested an Io orbiter/lander combo, with a HiRISE-style camera system on the orbiter. He since deleted his post, which makes mine look like I'm responding to Jason or someone else... *sigh*...

-the other Doug

Yeah - very bad forum conduct that - makes people look like nutters who've replied to nothing - I've PM'd 3488 and asked him to stop doing it.

Cheers

Doug

This is a situation where minimal quoting of the post being replied to is helpful, not only for clarity, but also to leave some sort of record of the exchange.

Speaking of Io from Europa, I haven't seen much USF discussion of the Flagship study preliminary reports to OPAG last month. Europa's is on line at:
http://www.lpi.usra.edu/opag/may_07_meetin...gship_study.pdf

A careful read shows that 1 m/pixel imaging is advocated with a Narrow-Angle Camera. This would achieve up to 2.5 km/pixel imaging of Io from near Europa orbit. Excellent monitoring is possible indeed, during the 1.5-2.5 years in Jupiter orbit prior to entering Europa orbit. (It's not clear whether the camera would/could be turned to Io during the 90+ day Europa "prime science" orbital mission itself, and the many months to >1 year "extended mapping" phase at Europa which the presentation advocates.)

-vg

VP may even lend his voice of support to the Europa orbiter mission if this were true.

According to VP the Europa orbiter should be refered to as "Io Precursor Mission"