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 …

In 1976, the Viking landers carried out the most comprehensive search for organics and
microbial life in the martian regolith. Their results indicate that Mars' surface is lifeless and …

Coupling between the lower and upper atmosphere, combined with loss of gas from the
upper atmosphere to space, likely contributed to the thin, cold, dry atmosphere of modern …

The history of Mars' atmosphere is important for understanding the geological evolution and
potential habitability of the planet. We determine the amount of gas lost to space through …

Observations of the Mars upper atmosphere made from the Mars Atmosphere and Volatile
Evolution (MAVEN) spacecraft have been used to determine the loss rates of gas from the …

Return of samples from the surface of Mars has been a goal of the international Mars
science community for many years. Affirmation by NASA and ESA of the importance of Mars …

Context. A complex and long-lasting solar eruption on 17 April 2021 produced a widespread
solar energetic particle (SEP) event that was observed by five longitudinally well-separated …

Abstract Two Mars Atmosphere and Volatile EvolutioN magnetic field sensors sample the
ambient magnetic field at the outer edge of each solar array. We characterized relatively …

Almost all planetary atmospheres are affected by disequilibrium chemical processes. In this
paper, we introduce our recently developed chemical kinetic model (ChemKM). We show …

Collisions with electrons from several sources are common throughout planetary
atmospheres. While in most circumstances direct electron impact is less significant than …