ebnelson wrote:
... have predicted mineral water (ice) on Mars for sometime. The question is how much (many predict quite a bit) and if it ever does more than sublimate away quickly when exposed to the atmosphere.

Alex writes:
One should note that the preliminary GRS suite data reported today are relatively unconstrained at this point. Bill Boynton, the GRS PI, was very careful to say, in response to a reporter's question, that quantities will take much longer analysis, though the strength of the hydrogen signal, especially over the residual south polar cap was certainly surprising.

That said, given the cryogenic temperatures no one (including the most optimistic Blue Mars types) is claiming that any of this putative H2O is in anything other than ice (or ice matrix) form.

ebnelson wrote:
The real interesting factoid will be to see how much CO2 is locked up as well.

Alex writes:
Well, at least from the standpoint of the GRS suite, discerning a carbon signal will entail *much* longer integration times (due to the relative difficulty in identifying carbon energy peaks in the spectra) with the GRS fully extended on its boom to remove noise from the spacecraft's contribution to the signal.

Alex R. Blackwell
University of Hawaii