Habitability is a widely used word in the geoscience, planetary science, and astrobiology
literature, but what does it mean? In this review on habitability, we define it as the ability of …

Bioregenerative life support systems (BLSS) are conceived of and developed so as to
provide food sources for crewed missions to the Moon or Mars. The in situ resource …

Comparing compositional models of the terrestrial planets provides insights into
physicochemical processes that produced planet-scale similarities and differences. The …

Reports of plumes or patches of methane in the martian atmosphere that vary over monthly
time scales have defied explanation to date. From in situ measurements made over a 20 …

Reconciling the geology of Mars with models of atmospheric evolution remains a major
challenge. Martian geology is characterized by past evidence for episodic surface liquid …

Magmatic degassing is ubiquitous and enduring, yet its impact on both planetary surficial
chemistry and how it may have varied among planetary systems remains imprecise. A large …

Chemical data from the MESSENGER spacecraft revealed that surface rocks on Mercury are
unusually enriched in sulfur compared to samples from other terrestrial planets. In order to …

The CHONS elements that constitute the outgassed atmosphere and exosphere have likely
been delivered by chondritic materials to the Earth during planetary accretion and …

What allows a planet to be both within a potentially habitable zone and sustain habitability
over long geologic time? With the advent of exoplanetary astronomy and the ongoing …

Clays form on Earth by near-surface weathering, precipitation in water bodies within basins,
hydrothermal alteration (volcanic-or impact-induced), diagenesis, metamorphism, and …