I study the atmospheres of Mars, Venus, and other terrestrial planets, seeking to understand the limits on planetary habitability imposed by water loss to space and atmospheric oxidation. Using data from ESA's Mars Express spacecraft, I discovered that Mars hydrogen loss to space is seasonally variable, significantly updating scientific understanding of Martian water loss. With photochemical modeling, I explained these variations, introducing new channels for H escape that can oxidize Mars over time. I am a key member of the NASA's MAVEN and the Emirates Mars Mission science teams, and am actively expanding my work to constrain Venus hydrogen escape and produce new planetary ultraviolet instrumentation in anticipation of upcoming missions. In 2020, I was one of six scientists selected for the inaugural class of NASA Planetary Science Early Career Award recipients. I mentor several research students and postdocs at LASP--- contact me if you're interested in joining my group or collaborating!