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Nasa Picks "juno" As Next New Frontiers Mission
Guest_BruceMoomaw_*
post Jun 1 2005, 10:10 PM
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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.)
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Guest_BruceMoomaw_*
post Jun 19 2005, 10:58 PM
Post #2





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As for Van Kane's comments on the "Io Observer": I don't understand it could flyby Io at two different positions in its orbit if its periapse was lower than Io's -- the only way it could pull that trick is if it had a circular orbit IDENTICAL to Io's except for being highly inclined (a trick which Cassini, in fact, will pull with Titan later in its primary mission, but which would probably sharply increase the amount of radiation the Io Observer would be exposed to). And, indeed, the description of it in the White Paper says flatly that it would continue reexaming regions on the same hemisphere of Io close-up over and over, at intervals of a month or less, to look for detailed changes. That mission by itself, however, could do a hell of a lot scientifically.

The really interesting question is whether you could combine this with another New Frontiers mission that the Decadal Survey and Solar System Roadmap groups have expressed interest in: a "Ganymede Observer" (actually, at this point a Ganymede-Callisto Observer) which would emulate Galileo by making repeated flybys of those two moons. The question is whether you CAN combine these two mission, to thus create a "Galileo 2" which could observe the entire Jovian system except for Europa in more detail -- the problem is that to get enough radiation resistance for Io Observer you probably need a polar orbit, which in turn means that you'd have to have an awful lot of delta-V to change the orbit's apoapse to make later flybys of Ganymede and Callisto. You MIGHT be able to pul it off with some particular clever gravity-assist flybys of the various moons, but the last time I brought it up this question was still wide open.

On another subject: there are really serious mass problems with flying a Jupiter Multiple Entry Probe mission, even separately from Juno (e.g., with the probes dropped off by a flyby). Given the phenomenal difficulty of Jupiter entry, they would all need big honking heat shields (and even all the companies which manufacture the substance used in the Galileo probe's heat shield have long since stopped doing so and would have to radically retool!). And when you add that to their need for a stout pressure hull (unlike the vented Galileo probe) to get down to the 100-bar level as they wish, that's a lot of mass. Add that to the fact that their main purpose was to map water, ammonia and H2S and winds at different locations and deeper depths -- and that Juno's orbital instruments, by itself, will do a lot of that -- and I think that the Galileo probe and Juno together have removed a lot of the justification for any more near-term Jupiter entry probes.

Now, the heat shield mass needed to enter any of the other three giant planets (including Saturn) is MUCH smaller -- and in the case of Uranus and Neptune, even at the great depths you want the probes to get down to (hopefully, as much as 1000 bars to reach the water cloud), temperatures are no problem at all and you could probably make the probe vented in structure, as both the Galileo probe and the deepest robotic submersibles on Earth are (although a strong radio data signal from that depth is a problem for any entry probe). For these reasons, I suspect that we're going to see deep entry probes for at least one of the other giant planets -- maybe even all of them -- before we see another Jupiter entry probe.
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JRehling
post Jun 20 2005, 01:25 AM
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[quote=BruceMoomaw,Jun 19 2005, 03:58 PM]
As for Van Kane's comments on the "Io Observer": I don't understand it could flyby Io at two different positions in its orbit if its periapse was lower than Io's
[/quote]

Imagine the way Halley's Comet's orbit intersects the Earth's (assuming the two orbits were nearly coplanar). They intersect in two places. On some passes, a close encounter will happen at one intersection, on some, at the other. On many, no encounter at all. Of course, there's no design behind the natural case. Clever choice of orbital period could allow close encounters to occur at both locations, on different orbits.

[quote]
The really interesting question is whether you could combine this with another New Frontiers mission that the Decadal Survey and Solar System Roadmap groups have expressed interest in: a "Ganymede Observer" (actually, at this point a Ganymede-Callisto Observer) which would emulate Galileo by making repeated flybys of those two moons. The question is whether you CAN combine these two mission, to thus create a "Galileo 2" which could observe the entire Jovian system except for Europa in more detail
[/unquote]

If Io were only to be observed from afar, then a perijove near Ganymede would suffice save a whole lot of delta-v.

[quote]
For these reasons, I suspect that we're going to see deep entry probes for at least one of the other giant planets -- maybe even all of them -- before we see another Jupiter entry probe.
*

[/quote]

Interesting, and Saturn would probably serve much the same scientific purposes, if the two giants ended up with similar ratios of raw material.
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Posts in this topic
- BruceMoomaw   Nasa Picks "juno" As Next New Frontiers Mission   Jun 1 2005, 10:10 PM
- - tedstryk   Great to hear. With the whole lunar program being...   Jun 1 2005, 10:44 PM
- - djellison   I take it this puts to bed the possibility of an N...   Jun 1 2005, 10:45 PM
- - Sunspot   Any proposals on what kind of camera?   Jun 1 2005, 11:39 PM
- - BruceMoomaw   No website yet, and I have no details on what kind...   Jun 1 2005, 11:51 PM
- - BruceMoomaw   Postscript: the mission selection actually was pla...   Jun 1 2005, 11:51 PM
- - Sunspot   They can't return to Jupiter without taking a ...   Jun 1 2005, 11:57 PM
- - edstrick   Atmosphere sounding instruments can also return ve...   Jun 2 2005, 06:49 AM
- - BruceMoomaw   Well, I can give you the full instrument list (alt...   Jun 2 2005, 10:37 AM
|- - garybeau   I would have thought / hoped the next Jovian missi...   Jun 2 2005, 12:39 PM
|- - tty   QUOTE (garybeau @ Jun 2 2005, 02:39 PM)I woul...   Jun 2 2005, 04:40 PM
|- - volcanopele   QUOTE (garybeau @ Jun 2 2005, 05:39 AM)I woul...   Jun 2 2005, 05:51 PM
|- - JRehling   QUOTE (garybeau @ Jun 2 2005, 05:39 AM)I woul...   Jun 6 2005, 03:26 PM
|- - tedstryk   I think the six-flybys analogy is a good one (seve...   Jun 6 2005, 05:02 PM
|- - Bjorn Jonsson   I vaguely remember reading somewhere that Juno wil...   Jun 6 2005, 05:26 PM
- - Chmee   Hopefully Juno wont have an umbrella style high ga...   Jun 2 2005, 03:03 PM
- - BruceMoomaw   Well, the Decadal Survey recommended -- and the ne...   Jun 3 2005, 01:17 AM
|- - Gsnorgathon   QUOTE (BruceMoomaw @ Jun 3 2005, 01:17 AM)......   Jun 3 2005, 02:16 AM
|- - Redstone   QUOTE (Gsnorgathon @ Jun 3 2005, 02:16 AM)Are...   Jun 3 2005, 02:32 PM
|- - Gsnorgathon   QUOTE (Redstone @ Jun 3 2005, 02:32 PM)... if...   Jun 3 2005, 09:58 PM
|- - garybeau   QUOTE The Jupiter icy moons' orbiter mission w...   Jun 4 2005, 12:18 PM
|- - tedstryk   I don't think getting to Europa is the biggest...   Jun 4 2005, 12:27 PM
- - BruceMoomaw   Jason is likely to be disappointed if he thinks of...   Jun 3 2005, 01:21 AM
|- - volcanopele   I never thought it would actually flyby Io, given ...   Jun 3 2005, 01:35 AM
|- - um3k   QUOTE (BruceMoomaw @ Jun 2 2005, 09:21 PM)it ...   Jun 4 2005, 02:38 AM
- - BruceMoomaw   BESIDES all that, there was one other major proble...   Jun 3 2005, 10:57 PM
- - edstrick   The Juno instrument selection looks quite "re...   Jun 4 2005, 09:04 AM
- - edstrick   Most of the P.R. talk on crashing Galileo into Jup...   Jun 5 2005, 01:56 AM
- - Decepticon   QUOTE ALL THESE WORLDS ARE YOURS EXCEPT EUROPA ATT...   Jun 5 2005, 03:29 AM
- - BruceMoomaw   I don't think the crashing of Galileo to ...   Jun 5 2005, 06:23 AM
|- - dvandorn   The other real difference between potential Martia...   Jun 5 2005, 09:30 AM
|- - garybeau   QUOTE (BruceMoomaw @ Jun 5 2005, 01:23 AM)Tha...   Jun 6 2005, 12:55 AM
|- - JRehling   Three miscellaneous comments for this thread, from...   Jun 6 2005, 01:30 AM
- - BruceMoomaw   QUOTE (edstrick @ Jun 5 2005, 01:56 AM)Most o...   Jun 5 2005, 06:32 AM
- - BruceMoomaw   While the new Solar System Roadmap (or, rather its...   Jun 5 2005, 06:53 AM
|- - tedstryk   QUOTE (BruceMoomaw @ Jun 5 2005, 06:53 AM)But...   Jun 5 2005, 10:35 AM
|- - Stephen   QUOTE (BruceMoomaw @ Jun 5 2005, 06:53 AM)But...   Jun 8 2005, 09:52 AM
- - BruceMoomaw   QUOTE (edstrick @ Jun 4 2005, 09:04 AM)The Ju...   Jun 5 2005, 07:09 AM
|- - tedstryk   QUOTE (BruceMoomaw @ Jun 5 2005, 07:09 AM)...   Jun 5 2005, 10:32 AM
- - Redstone   QUOTE (garybeau @ Jun 4 2005, 12:18 PM)The or...   Jun 6 2005, 02:17 AM
|- - Bob Shaw   Some comments on life on Mars (and elsewhere) and ...   Jun 6 2005, 01:58 PM
- - BruceMoomaw   Yeah, it will be -- which will certainly interfere...   Jun 6 2005, 07:27 PM
- - Myran   dvandorn wrote: "I think the most boring thi...   Jun 8 2005, 12:12 PM
|- - JRehling   QUOTE (Myran @ Jun 8 2005, 05:12 AM)As for sa...   Jun 8 2005, 04:47 PM
- - Decepticon   They are sending a Probe to Jupiter and according ...   Jun 10 2005, 02:03 AM
|- - JRehling   QUOTE (Decepticon @ Jun 9 2005, 07:03 PM)They...   Jun 10 2005, 04:30 PM
|- - tedstryk   Another factor to consider is that a decent Europa...   Jun 10 2005, 04:55 PM
- - Gsnorgathon   FWIW, a wee writeup at Astrobio.net, and the ever-...   Jun 10 2005, 05:30 AM
- - edstrick   Part of the problem is that *any* Europa orbiter m...   Jun 11 2005, 12:16 AM
|- - Decepticon   Even with Galileo type flybys would make me happy....   Jun 11 2005, 02:37 AM
- - Phil Stooke   Ted, I missed your Amalthea images until just now ...   Jun 11 2005, 03:21 AM
|- - tedstryk   QUOTE (Phil Stooke @ Jun 11 2005, 03:21 AM)Te...   Jun 11 2005, 03:30 AM
- - BruceMoomaw   Juno's orbit will go from only 4500 km above J...   Jun 11 2005, 09:04 PM
|- - MiniTES   QUOTE (BruceMoomaw @ Jun 11 2005, 09:04 PM)Ju...   Jun 15 2005, 02:51 PM
- - Phil Stooke   Spinning doesn't have to mean Pioneer 10-class...   Jun 15 2005, 03:28 PM
- - Decepticon   Can Juno at least take Movie like animations of th...   Jun 15 2005, 08:17 PM
- - BruceMoomaw   According to the Space.com article, it will indeed...   Jun 15 2005, 10:17 PM
- - BruceMoomaw   "...rathern using a filter wheel" is rea...   Jun 15 2005, 10:19 PM
- - Sunspot   Oh... thats a shame, I guess we probably wont ever...   Jun 15 2005, 10:46 PM
- - Phil Stooke   Actually we will see some good stuff in 2007 from ...   Jun 15 2005, 11:26 PM
- - edstrick   Why is it spinning? Field and Particles instrument...   Jun 15 2005, 11:27 PM
- - BruceMoomaw   Fear not! We WILL see excellent images of Jup...   Jun 16 2005, 02:26 AM
- - BruceMoomaw   Footnote: the reason that the radiation dose for a...   Jun 16 2005, 02:38 AM
|- - MiniTES   QUOTE (BruceMoomaw @ Jun 16 2005, 02:38 AM)Fo...   Jun 16 2005, 05:20 PM
|- - djellison   QUOTE (MiniTES @ Jun 16 2005, 05:20 PM)How th...   Jun 16 2005, 06:25 PM
- - edstrick   And.... It's moving perpendicular to the belts...   Jun 16 2005, 05:43 AM
- - BruceMoomaw   It would be more accurate to say that they intend ...   Jun 16 2005, 07:44 AM
- - Analyst   Bruce, I want your optimism when it comes to futur...   Jun 16 2005, 12:34 PM
|- - JRehling   QUOTE (Analyst @ Jun 16 2005, 05:34 AM)Bruce,...   Jun 16 2005, 01:53 PM
- - BruceMoomaw   Yup -- they've had solar panels planned for a ...   Jun 17 2005, 12:08 AM
- - BruceMoomaw   QUOTE (Analyst @ Jun 16 2005, 12:34 PM)Bruce,...   Jun 17 2005, 12:21 AM
- - BruceMoomaw   You'll notice that I HAVE backtracked from the...   Jun 17 2005, 12:25 AM
|- - vjkane2000   QUOTE (BruceMoomaw @ Jun 16 2005, 05:25 PM)Yo...   Jun 17 2005, 02:55 AM
|- - JRehling   QUOTE (vjkane2000 @ Jun 16 2005, 07:55 PM)The...   Jun 17 2005, 04:19 PM
|- - vjkane2000   QUOTE (JRehling @ Jun 17 2005, 09:19 AM)A dif...   Jun 17 2005, 05:23 PM
- - BruceMoomaw   It's a possibility -- but I suspect you're...   Jun 17 2005, 07:17 AM
|- - gpurcell   QUOTE (BruceMoomaw @ Jun 17 2005, 07:17 AM)In...   Jun 17 2005, 07:39 PM
- - edstrick   You really *do* want a very high power telescopic ...   Jun 17 2005, 07:22 AM
- - BruceMoomaw   Turns out I misread that white paper -- Europa Orb...   Jun 17 2005, 07:22 AM
- - vjkane2000   Cost is, of course, a major issue for any Jupiter ...   Jun 17 2005, 02:00 PM
- - BruceMoomaw   Damned if I know, especially with this president -...   Jun 19 2005, 10:29 PM
|- - Bob Shaw   Bruce: Are you talking about the Hubble II comple...   Jun 19 2005, 10:47 PM
- - BruceMoomaw   As for Van Kane's comments on the "Io Obs...   Jun 19 2005, 10:58 PM
|- - JRehling   Imagine the way Halley's Comet's orbi...   Jun 20 2005, 01:25 AM
- - BruceMoomaw   "Are you talking about the Hubble II complete...   Jun 19 2005, 11:54 PM
- - BruceMoomaw   (1) "Imagine the way Halley's Comet...   Jun 20 2005, 02:55 AM
|- - JRehling   QUOTE (BruceMoomaw @ Jun 19 2005, 07:55 PM)Ah...   Jun 20 2005, 08:55 PM
- - gpurcell   I've always thought that the best deorbit miss...   Jun 20 2005, 03:09 PM
- - BruceMoomaw   Actually, there are a hell of a lot of things they...   Jun 21 2005, 12:31 PM
|- - JRehling   QUOTE (BruceMoomaw @ Jun 21 2005, 05:31 AM)Ac...   Jun 21 2005, 03:31 PM
|- - vjkane2000   QUOTE (JRehling @ Jun 21 2005, 08:31 AM)Indee...   Jun 22 2005, 09:10 AM
- - BruceMoomaw   Well, keep in mind that Cassini's 45 close fly...   Jun 22 2005, 10:52 PM
- - BruceMoomaw   The presentations from the June OPAG meeting are n...   Jun 29 2005, 06:02 PM
|- - imran   Thanks for the links, Bruce. I am surprised too t...   Jun 29 2005, 08:37 PM
- - BruceMoomaw   This hardly means that they're not considering...   Jun 29 2005, 10:28 PM
- - BruceMoomaw   And, for one recent JPL study of a Titan aerobot m...   Jun 29 2005, 10:31 PM
|- - JRehling   QUOTE (BruceMoomaw @ Jun 29 2005, 03:31 PM)An...   Jun 30 2005, 05:20 PM
- - BruceMoomaw   Actually, we DO need more surface observation poin...   Jun 30 2005, 06:50 PM
- - tedstryk   QUOTE (BruceMoomaw @ Jun 30 2005, 06:50 PM)Ac...   Jun 30 2005, 06:58 PM
- - JRehling   QUOTE (BruceMoomaw @ Jun 30 2005, 11:50 AM)Ac...   Jun 30 2005, 07:15 PM
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