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_*]

Actually, we DO need more surface observation points on Venus. One of the highest-priority goals of landings (specified in the new Roadmap) is to look for patches of granite or andesite crust which would indicate the existence of oceans on ancient Venus -- and the best place by far to look for those is in the "tessera" patches, which have been the top-priority landing sites for any American Venus mission for years. We would also like to take a look at those puzzling areas of high radar reflectivity on Venus' high-altitude terrain -- and, on top of that, keep in mind that even the Soviet landers didn't do any mineralogy at all of their own basaltic landing sites.

The question is whether the best way to do this is by a surface rover, an aerobot, or a larger number of multiple stationary landers. Frankly, I'm inclined to go with the latter -- we have the technology for those RIGHT NOW. (We might also be advised to try to develop in-situ age-dating instruments for Venus' surface; we have already done some promising initial work on those, and God knows it would be easier than a Venus sample return -- which I expect to see Congress fund on the same day O.J. finds the real killers.)

[JRehling]

Actually, we DO need more surface observation points on Venus.  One of the highest-priority goals of landings (specified in the new Roadmap) is to look for patches of granite or andesite crust which would indicate the existence of oceans on ancient Venus -- and the best place by far to look for those is in the "tessera" patches, which have been the top-priority landing sites for any American Venus mission for years.  We would also like to take a look at those puzzling areas of high radar reflectivity on Venus' high-altitude terrain -- and, on top of that, keep in mind that even the Soviet landers didn't do any mineralogy at all of their own basaltic landing sites.

All good points; I meant that we know what the terrain is like on representive locations on Venus, and we could say that a rover would operate with no problem on Venera 10/Venera 14 terrain, and not much problem on Venera 9/Venera 13 terrain. Of course, we can easily radar-survey Venus to find slopes and roughnesses at arbitrary scales.

The kinds of terrain you mention are indeed different and worth checking out. And may be tough to rover on, in the case of tessera; tough to hit precisely in the case of the radar-bright heights.

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. Venus is a big place, and just as current Mars lander site selection depended upon orbital surveys to do us much good, we would be well served by some light/broad recon of Venus before we pay for landers.

The question is whether the best way to do this is by a surface rover, an aerobot, or a larger number of multiple stationary landers.  Frankly, I'm inclined to go with the latter -- we have the technology for those RIGHT NOW.  (We might also be advised to try to develop in-situ age-dating instruments for Venus' surface; we have already done some promising initial work on those, and God knows it would be easier than a Venus sample return -- which I expect to see Congress fund on the same day O.J. finds the real killers.)

We don't have the technology for long-duration Venus landers right now -- well, unless nuclear-powered refrigeration is the way we keep the instruments alive. An aerobot may or may not require less technological development than a seriously long-lasting Venus stationary lander, because the ability to go aloft into the cool heights is certainly more of a no-moving-parts approach than the refrigeration method. Whichever is easier, a stationary Venus lander with seismometry is a must-have at some point. But I disagree that a lander-first surely offers the best science/cost plan. Another entry in the field is also a very small, VAMP-like probe that aces the isotopic analysis of the atmosphere.

I might say that a good candidate for the next Venus mission would be an isotopic analyzer that also tested some multispactral imaging on a surface unit boundary to see what an aerobot/airplane could do with a longer below-cloud groundtrack.