Winston,
If you remember, when the probe was first used the surface disrupted and gaped (a duricrust effect). This could well have opened a gap enabling the atmosphere to interact with the probe. In which case the probe would have measured the atmospheric trace vapour rather than any free molecules in the regolith. Subsequent measurements where the fidelity of the surface was maintained found no free H2O molecules beneath the surface. IMHO a much more logical cause and effect than a dramatic change in the sub surface environment post landing.
I note that the latest article does not mention relative humidity bot of necessity when the temperature drops low enough the atmosphere must give up the trace water vapour. But I have never followed the tenuous logic chain that says it must disappear into the soil? Sublimate as ice (frost) on the surface yes - we have seen that. Ice crystals as cloud yes - polar cloud formation at night is well recorded from satellite data. But as free H2O molecules in the regolith, the probe says no. Perhaps Dr Zent is a proponent of the regolith annual water storage cycle hypothesis. If so then he is understandably frustrated that this theory has apparently been disproven.
Moisture has become a 'rubbery' term Winston and apparently can be applied at whim to all three states of Hydrogen Oxide. Ice which at these temperatures is just another rock. Water which is the liquid state of Hydrogen Oxide has never been seen on Mars. (Lets not argue about possible brines, or interpretations of new gullies or dry/wet flow traces. Liquid water has never been identified on Mars). The third phase is free H2O molecules or water vapour which exist as a trace component of the atmosphere.
But from the probe results, this does not penetrate the surface.
