Determine daytime crack-closure and interior-drying rates

Determine the rates at which hygroscopic-salt cracks opened by nighttime cooling close during daytime warming and the rate at which the mineral interior dries under Mars-relevant conditions, in order to assess whether liquid water can be retained during the daytime.

Background

The proposed microhabitat mechanism depends on nighttime crack opening, penetration of deliquescent brine into the crystal, and subsequent daytime crack closure that limits water loss. The paper explicitly identifies the relative rates of crack closure and interior drying as necessary measurements for evaluating whether the proposed environment remains wet long enough to support hypothetical microorganisms.

References

In this context, it would be important to know the rate at which cracks that opened during the nighttime cooling close during daytime warming and, in parallel, how quickly the interior of the mineral can dry out, since maintaining a potential habitat requires that it does not dry out during the day.

— Current water trapping micro-habitats on the surface of Mars  (2609.01156 - Bognar et al., 1 Sep 2026) in Section 5, Suggestions for future research

It would also be worthwhile to further investigate whether bulk thermal expansion under Martian conditions can realistically result in crack opening and closing, since crack evolution likely depends on additional factors such as grain size, elastic properties, pre-existing microfractures and thermal gradients.

— Current water trapping micro-habitats on the surface of Mars  (2609.01156 - Bognar et al., 1 Sep 2026) in Section 5, Suggestions for future research

Future studies should also examine whether crack closure under Martian conditions can sufficiently limit vapor transport to enable temporary liquid retention.

— Current water trapping micro-habitats on the surface of Mars  (2609.01156 - Bognar et al., 1 Sep 2026) in Section 5, Suggestions for future research