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, I can give you the full instrument list (although not in much detail):

(1) Multi-channel microwave spectrometer (for very deep temperature, water vapor and ammonia profiles).

(2) UV imaging spectrometer (another version of the "ALICE" on Rosetta and New Horizons).

(3) Magnetometer

(4) Plasma detector ("JADE", or Jovian Auroral Distributions Experiment).

(5) Energetic particle detector

(6) Plasma wave detector

(7) Camera

Plus the radio science experiment -- which is actually the most important one on Juno, with the possible exception of the microwave spectrometer and magnetometer, given its ability to make gravity-field measurements so precise that they will settle both the question of whether Jupiter has a rocky core, but even detect the convection currents from very deep winds.

Nothing in there for images, except for the camera itself and ALICE (plus whatever maps they get out of the microwave instrument). As I say, this is a very important mission scientifically -- giving us our deepest look yet into Jupiter's innards -- but it won't have much charm for nonscientists.

[garybeau]

I would have thought / hoped the next Jovian mission would have been a Europa orbiter. This is one of the few places besides Mars that holds any prospects for life. Whatever happened to Nasa's "follow the water" mantra. The Juno mission just doesn't stir up any passion.

[JRehling]

I would have thought / hoped the next Jovian mission would have been a Europa orbiter. This is one of the few places besides Mars that holds any prospects for life.  Whatever happened to Nasa's "follow the water" mantra. The Juno mission just doesn't stir up any passion.

Well, forget for a moment the sibling (parent) rivalry between Jupiter and the other worlds near it.
What we're talking about here is Jupiter -- one of the three most central planets to space exploration -- finally getting its Pioneer Venus, finally getting its Mariner 9. Among the worlds that have had orbiters (preCassini), one that is totally unique in structure and atmosphere. And with Galileo's Jupiter science having been a mere trickle, one that has been seen more like a world that's received six flybys than has ever been the subject of an orbiter's science in the way that Mars has received six, and Venus several (mainly Soviet, but two American).
It's got an atmosphere that is in some ways (thick water clouds, for one; sweeping storm fronts bearing rain) more earthlike than either Venus's or Mars's. A structure which is totally unlike that seen in the inner solar system. And note that Cassini is not giving Saturn the look that Juno would give Jupiter. Cassini's closest approach to Saturn already has taken place, and it wasn't even looking at the planet. Saturn's rings are both a barrier for close approaches and a factor that neutralize the particle environment that we want to see at Jupiter. Remember, Jupiter is our best analogue to most of the extrasolar planets we've discovered, and knowing it better could prove essential, obliquely, to our efforts to find earthlike planets sharing those systems with giant neighbors.
I don't think the first *real* Jupiter orbiter is a low-passion mission at all. With its camera a minor player, it may rank low in terms of (intended) eye candy, but planetary science is a forensic science, and fingerprints may seem less exciting than photos of a corpse, but they can be more telling about the history.
I'm excited about Juno -- even eye candy should be forthcoming. But I'm pretty curious about what's beneath the hydrogen. Whether it's 1 earth-mass or 30 earth-masses may have little visible effect at the surface, but the result will tell us a lot about origins. And given that the source of magnetic fields remains a bit of a mystery (eg, Mercury's; the large differences between those of the giant planets), more information on that matter is going to be welcome as well.

[tedstryk]

I think the six-flybys analogy is a good one (seven if you count Ulysses Jupiter Distant Flyby a year or two ago which did yield some interesting particle and fields data, particularly with regards to dust from Io) in terms of data return, although it was over an extended period of time, so for things such as Io coverage, it at least had a long temporal baseline. I see it as a series of mini-flybys. I do hope that an Amalthea flyby can be squeezed into Juno. It will be penatrating in that far, and I don't see another spacecraft doing that for the forseeable future (I don't think it would be good to even risk an Io mission). It is a shame Galileo didn't take remote sensing data. Given its illness and how badly it got zapped however, had it been making turns to do imaging at the time of the encounter at first Io and then Amalthea, it would likely have at least safed, costing us the data on the near-Amalthea particles, a lot of particle and fields stuff, and we might have lost the spacecraft all together. The budgetary issues non withstanding, I would have loved Galileo images close to Amalthea, but I am skeptical the spacecraft could have pulled it off. I have been working on some of the images Galileo took, and it is a very interesting world, especially given the new shape-model release. I have worked hard on the high resolution E26 image, and you may have seen my result - it is faux-super-res, created by stacking various resamplings and processings of the same image. It creates a relatively sharp image despite oversampling, although it doesn't truly increase resolution. I also tried to correct overexposure in part of the image.

Also, have worked on the only three Galileo color images of Amalthea, taken during the primary mission. I created color images using the various filter combinations available (the E4 data had a fourth filter available, but I didn't use it for color). I also used all available images (3 for G2 and C3, 4 for E4, although the E4 data was so distant it really wasn't worth it) to creat super resolution black and white images. I then overlaid the color data on these. Here is the result:

[Bjorn Jonsson]

I vaguely remember reading somewhere that Juno will be spin-stabilized, probably making it difficult to obtain high-res images of satellites like Amalthea or even Io during fast flybys. Or maybe I'm confusing Juno with something else (Inside Jupiter/JASSI etc.). Does anyone know if it will be spin-stabilized ?