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Galileo Amalthea Flyby Threatened
vince writes "The Galileo spacecraft will fly by Jupiter's moon Amalthea on November 5th. This is the *only* close flyby of this moon Galileo will make, but (as currently planned) it will not return any images, in order to save a paltry $1m - $1.5m. Looks like a grassroots campaign is going to be necessary to save the flyby."
Actually, small moons aren't interesting. Well, not in the same way and to the same degree as the Galilean moons. The Galilean moons are large enough to be spherical and to show geological processes and to hold on to trace atmospheres. That means there is probably much more to study with them than with the smaller moons, which have little geology aside from impact cratering. This is not meant to be a value judgement, merely an unfortunate pragmatic fact.
Mission planners also undoubted considered some basic orbital facts, here. The small moons of Jupiter are all either quite a bit outside the Gailean orbits or within Io's orbit. You might think you could sneak visits to the former as the probe swings out from or in to Jupiter on its very elliptical orbit. But ALL of the outer moons have signficant inclinations. The odds of meeting one of them near the equator of Jupiter is slight, given the number of coincidences you'd need. As for the inner moons (Amalthea, Phoebe, Adrestea and Metis), they're all interior to Io. This is actually very bad for Galileo. You'll recall that getting in as close to Jupiter as Io has causes problems, thanks to the magnetosphereic plasma. The farther in you go, the worse it gets. They're only doing this now because Galileo is well past its life expectency and beginning to fail anyway.