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_*]

Jason is likely to be disappointed if he thinks of the Europa orbiter as "a 2-year Io mission with one month in Europa orbit". The plans for it, which have long ago been worked out in detail, call for it to make repeated flybys of Ganymede and Callisto during its 2-year orbital tour before settling into Europa orbit -- but NOT to get any closer to Jupiter than Europa, in order to minimize its radiation dose. The plan now is not even to have it make a close approach to Jupiter at its initial arrival -- instead, it will approach at Ganymede's distance and make a Ganymede flyby to help brake itself into Jovian orbit (rather than using Io for that purpose, as Galileo did).

[um3k]

it will approach at Ganymede's distance and make a Ganymede flyby to help brake itself into Jovian orbit (rather than using Io for that purpose, as Galileo did).

I was just pondering that concept. My idea, though, is even more ambitious: A Europa sample return mission that utilizes multiple flybys of Jovian moons in order to slow down enough to make a soft landing on Europa. A core sample would then be taken, which would be segmented into shorter pieces, and then launched into Jovian orbit, where it would be picked up by a larger orbiter. This would then conduct many more flybys in order to reach Jovian escape velocity. It would finally enter a solar orbit that would return it to Earth. The purpose of all the gravity assists, of course, is to use as little fuel as possible.