Thomas Lee Elifritz wrote:
Since we now definitely know that Mars is basically a frozen muddy glacial
ice ball just a few meters below the surface (to a depth of several
kilometers), and that Mars is only dry and desiccated in the top few meters
of soil, then the whole in situ fuel manufacturing scenario suddenly becomes
considerably more plausible.

We do not 'definitely know' that.

The best interpretation of the currently available
evidence is that; however, speculating about the
subsurface layers without a *lot* more remote sensing,
including some really good radar work, and/or surface
penetrator/drill sampling, is really a high degree of
hubris.

The only resources for ISRU I count on personally are
the air, though I agree that enough evidence for
significant subsurface water exists, and its value is
so high if present, that we really ought to go
specifically looking to confirm its apparent
presence.

The air, by the way, clearly includes useful quantities
of water (though it's a lot harder to extract than CO2).
WAVAR seems quite reasonable and reliable as a concept.
An ISRU test mission should bring a small WAVAR test rig
even if we don't need the water for the propellants cycles.


-george william herbert