There’s another problem with voyages to Europa — it’s right smack in the middle of Jupiter’s radiation belts.

Contaminating the ocean is probably not an immediate issue, since the ocean, if present (and it probably is), would be about 50 km beneath the ice. Humanity has never dug a hole that deep and may never do so.

But that’s just me …

Cheers.

Paul

The Meridiani Journal
a chronicle of planetary exploration
http://web.mac.com/meridianijournal

I know that Mars has large areas of Olivine on the surface. From what I understand this mineral readily weathers in water. I don’t know how quickly it weathers. In decades, millenia, or millions of years? I don’t know when it formed before or after a supposed Mars wet period. Does this put an upper limit on how much water Mars has or had? http://www.psrd.hawaii.edu/Nov03/olivine.html

I think we should explore Mars just for the sake of exploring Mars, not to look specifically for water (and life). Because if it’s hyped that Mars was very wet (and by implication could have harbored life), and it turns out that Mars was never very wet nor very hospitable for life then I think we lose public interest and support. We can learn as much about the Earth by contrast in studying Mars as by what the two worlds have in common. Discovering liquid water and life on Mars would be icing on the cake.

I’m more inclined to accept that Mars was damp but not wet. Any pointers to more info would be appreciated.

Why the New Gully Deposits Are Not Dry Dust Slope Streaks
MGS MOC Release No. MOC2-1621, 6 December 2006

There are many excellent images on this page which compare the gully deposits versus slope streaks which are common on Mars.

“In developing geologic interpretations from inspection of images, many factors are considered: size, relief, shape and pattern, color or brightness, texture, and association (context). Context is often the final discriminator between features that look similar. It is undeniable that the gully deposits resemble slope streaks, but they do not share the same context. If they are slopes streaks formed by downslope movement of dry, unconsolidated dust, then they are extremely rare features, because the new gully deposits (a) do not occur in regions where slope streaks occur, (b) are not found near any dark slope streaks, while typical light slope streaks have dark ones nearby, and (c) formed during the MGS MOC mission, while no new light slope streaks were observed to have formed anywhere else on the planet during the mission. Conversely, their presence within craters with gullies and the existence of similar light-toned features on other gullied (and in some cases on adjacent) slopes, with which they share geomorphic attributes, may be coincidental but is probably not. The gullies themselves provide the context for the gully deposits, and argue for a genetic relationship.”

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“It rules out pure liquid water,” said lead author Jon D. Pelletier of The University of Arizona in Tucson
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They added that their research does not rule out the possibility that the images show flows of very thick mud containing about 50 percent to 60 percent sediment. Such mud would have a consistency similar to molasses or hot lava. From orbit, the resulting deposit would look similar to that from a dry avalanche.
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So the Pelletier study is not ruling out liquid water at all, just pure liquid water. Well, duh. I doubt pure liquid water could even travel 100 meters without evaporating first in a 0.006 atm atmosphere. Who claimed that it was pure water? Certainly not Malin.