Nasa Picks "juno" As Next New Frontiers Mission Options

[Guest_BruceMoomaw_*]

http://www.nasa.gov/home/hqnews/2005/jun/H...rontiers_2.html

Yeah, I know it ain't Saturn, but we don't seem to have any proper slot for Jovian news -- including yesterday's totally unexpected announcement that Amalthea's density is so low as to suggest that it's a highly porous ice object; maybe a captured Kuiper Belt Object reduced to rubble by infalling meteoroids. As Jason Perry says, this might explain those previously mysterious light-colored patches on Amalthea -- they may be its underlying ice, exposed by impacts that punched through the layer of sulfur spray-painted onto it by Io.

Scott Bolton has been pretty talkative to me already about the design of Juno. It certainly won't be as good in the PR department as Galileo or Cassini, but it DOES carry a camera -- as much for PR as for Jovian cloud science, according to Bolton. And since the latitude of periapsis of its highly elliptical orbit will change radically during the primary mission, I wonder if they might be able to set up at least one close photographic flyby of Io and/or Amalthea? (I believe, by the way, that this selection is a bit ahead of schedule -- and it certainly indicates that NASA's science program under Griffin won't be a complete slave to Bush's Moon-Mars initiative.)

[Guest_BruceMoomaw_*]

Well, the Decadal Survey recommended -- and the new NASA Solar System Roadmap document backs again -- a Europa orbiter; but it's too expensive to be an NF mission. Instead, the Roadmap report calls it a "small Flagship" mission -- that is, in the $700 million to $1.5 billion price range -- and strongly recommends it for a launch in 2014, maybe even with a small Europa lander added. Hopefully they'll finally stop screwing around and fly the damn thing, now that O'Keefe's JIMO fairy tale has been taken back off the table. (Rumor has it that, due to his engineering ignorance, he was bamboozled into backing that grotesquerie by his pro-nuclear brother.)

Indeed, the Roadmap recommends two more small Flagship missions after that at 5-year intervals -- the first probably being a Titan Explorer (an aerobot to repeatedly sample the surface looking for organics, and relaying its data directly back to earth without a Titan orbiter), and the second being a Venus Explorer (some kind of long-lived surface vehicle using the temperature-resistant electronics that will hopefully be available by 2024 -- maybe a surface rover as the report recommends, but maybe instead a repeat-landing aerobot like the Titan mission). Then at some point in the 2025-35 period, it recommends one really big Flagship mission in the multi-billion dollar class, with several possible targets.

[Gsnorgathon]

...
Hopefully they'll finally stop screwing around and fly the damn thing, now that O'Keefe's JIMO fairy tale has been taken back off the table.
...

I always thought JIMO sounded too good to be true. I hate it when I'm right about that kind of stuff.

Are there any informed critiques of JIMO on the web? I just figured it wasn't going to happen because of the everyone-gets-a-pony aspect, as opposed to actually knowing anything.

[Redstone]

Are there any informed critiques of JIMO on the web? I just figured it wasn't going to happen because of the everyone-gets-a-pony aspect, as opposed to actually knowing anything.

Not a detailed critique, but here is what Mike Griffin said to Congress about JIMO

The Jupiter icy moons' orbiter mission was, in my opinion, too ambitious to be attempted. Let me give a couple of specifics.

The vehicle would have required at least two heavy-lift launches to put into orbit, where it would have been assembled prior to its departure from earth to go to Jupiter. That would have been an extremely expensive undertaking, one which we have not performed before.

The nuclear electric propulsion system being developed for it does not presently exist, would not exist for some time and, if successfully developed, would have required approximately twice the world's annual production of xenon to be fueled -- to carry out the mission. It was not a mission, in my judgment, that was well-formed.

The original purpose of the Jupiter icy moons' orbiter was to execute a scientific mission to Europa -- Europa, a moon of Jupiter, which is extremely interesting on a scientific basis. It remains a very high priority, and you may look forward, in the next year or so, maybe even sooner, to a proposal for a Europa mission as part of our science line. But we would not -- we would, again, not -- favor linking that to a nuclear propulsion system.

[garybeau]

The Jupiter icy moons' orbiter mission was, in my opinion, too ambitious to be attempted.

The original concept for a Europa Orbiter was not a multi-billion dollar, nuclear propulsion behemoth, but rather a <1 billion scout mission with radar and imaging capabilities. The proposed mission had overwhelming support from both the public and scientific community.

http://www.planetary.org/html/society/pres...vey_results.htm

http://www.planetary.org/html/UPDATES/Pluto/plutoeuropa.html

It's only because of the shortsighted, politic driven decision making that that this mission has been "on again - off again" so many times.
Fortunately, NASA is not the only game in town any more. Maybe we will see an ESA Europa mission while NASA is trying to find its way.

http://sci.esa.int/science-e/www/object/in...fobjectid=35982

I don't think getting to Europa is the biggest hurdle to overcome. I think one of most difficult challenges will be to get there without contaminating the moon with terrestrial organisms. I don't think that it is possible to completely sterilize a spacecraft and allow it to impact the moon. Enough fuel would have to be brought to allow it to leave the orbit of Europa when the mission is over and de-orbit into Jupiter the same way that Galileo did.

My apologies for getting OT.