Talking about a different planetary body for a change, there's news about Europa.

New Scientist reports on a finding that the ice on Europe is highly acidic, and contains hydrogen peroxide. Acid as in a pH of 0 if melted, very strong stuff.

The H2O2 is likely to due to radiation effects on the surface, but the sulfuric acid could be due to radiation-driven surface reactions with sulfur dust from Io, surface reactions using salts (sulfates) erupted up from the ocean below, or the ocean itself might be highly acidic (which is bad for most Earth life, but there are acid-tolerant bacteria and having an interesting, energetic chemical soup might not be the worst way to get biology going).

Either way, it does raise the problem of making any sort of ice-melting probe acid-proof.

http://www.newscientist.com/news/news.jsp?id=ns99994664