Dynamic temperature fields under Mars landing sites and implications for supporting microbial life

Area of Science:

• Planetary Science
• Astrobiology

Background:

• Surface temperatures on Mars are generally too low for liquid water and terrestrial life.
• Diurnal temperature variations can create transient habitable niches beneath the Martian surface.

Purpose of the Study:

• To model subsurface temperature dynamics at Mars lander sites.
• To assess the potential for transient habitable conditions for microbial life on Mars.

Main Methods:

• Application of a thermal model to data from Viking 1, Viking 2, Pathfinder, Spirit, and Opportunity landing sites.
• Analysis of dynamic subsurface temperature fields.
• Use of 253 K as a benchmark temperature for microbial metabolic activity.

Main Results:

• Subsurface temperatures reach 253 K at diurnal peak heating for at least part of the year at all modeled landing sites.
• Areas within 40 degrees of the equator experience 253 K subsurface temperatures for a fraction of the year, and within 20 degrees for most of the year.
• Aqueous salt solutions on Mars can remain liquid below 253 K.

Conclusions:

• Transient habitable conditions, with temperatures above 253 K, exist beneath the Martian surface.
• Life on Mars would need to tolerate significant daily and seasonal temperature swings.
• The presence of salts could allow for liquid water even at temperatures below 253 K.