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_*]

One more footnote here, which I forgot to include earlier, in response to John's comment: "I'd aim for identification of granite from above rather than trying to hit the bullseye with a tessera lander. I don't know if the high temps + CO2 allow an IR spectroscopic approach from aloft below the clouds, but a TES (instrument on Mars Global Surveyor) -type survey would give loads of coverage if flown on a balloon or airplane that cruised over one of the big tessera areas. I'd be afraid of committing too much money to a lander (even a rover) and landing in the wrong valley, one valley over from the geologically older one."

As with the high reflectivity regions -- but even more so -- it would be very hard to actually miss one of the tessera regions, which are often hundreds of km across. Also, it would be very good to be able to do some age-dating of a tessera patch (along with the main basalt plains, and maybe one of the more recent volcanic regions) in-situ with landers (although that experiment doesn't seem to have been on Larry Esposito's "SAGE" proposal for mutiple Venus landers for the last New Frontiers selection).

Once again, however, an excellent case can be made that -- before we dispatch any Venus landers at all -- we should fly another SAR mapping mission, with much higher resolution, in a low circular Venus orbit, as suggested by the DPS White Paper group a few years ago (and just repeated by the VEXAG group). As with Mars, a good deal of mapping reconnaissance is important in picking out the best possible Venusian landing sites, given the inevitable rarity of actual Venus landings.