Nasa Picks "juno" As Next New Frontiers Mission |
Nasa Picks "juno" As Next New Frontiers Mission |
Guest_BruceMoomaw_* |
Jun 1 2005, 10:10 PM
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Guests |
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_* |
Jun 5 2005, 06:32 AM
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QUOTE (edstrick @ Jun 5 2005, 01:56 AM) Most of the P.R. talk on crashing Galileo into Jupiter reffered to the planetary quarantine problem. They barely discussed the real reasons for the end of mission. 1.) The spacecraft was running out of orbit trim propellant. 2.) Radiation damage was making the spacecraft "sicker" and sicker. Things were progressively failing, going intermittant, flakey, etc. 3.) $$$$$... The mission was expensive to operate and track because of the enormous Deep Space Network effort to return a trickle of data from the omin antenna, after the main antenna failed to open. But essentially, the spacecraft was dying. Yep -- the Space Studies Board had done a detailed appraisal for NASA years earlier of just how much of an extended mission for Galileo was scientifically cost-effective. They ended up going for the most ambitious possible plan, except that they rejected the idea of trying to photograph Amalthea during its flyby on the grounds that the craft would almost certainly develop serious radiation collywobbles during that period anyway (which, indeed, it did). They did decide to add an imaging plan for its final Io flyby (something Jason Perry privately worked like hell to encourage) -- only to have that also ruined by a radiation reset of the sort that fouled up almost all of their Io flybys to varying degrees. There is no way you can say that NASA threw away this spacecraft wastefully -- I'm amazed that it lasted as long as it did. (I'm even more amazed that they were able to squeeze so much valuable science out of it after the HGA disaster -- when I first heard about that in 1991, I figured that all of the mission except the entry probe was dead.) |
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