Ultraviolet Extinction Sky Survey (UVESS): A mission concept for probing the interstellar medium in the Milky Way and Local Group galaxies

This paper introduces a mission concept focused on investigating the composition of the interstellar medium (ISM) in the Milky Way and nearby Local Group Galaxies. It emphasizes the prominent ultraviolet (UV) extinction feature at 2175 Å observed in reddened OB stars and proposes carbonate grains as potential carriers. The mission employs UV spectroscopic instruments to map the spatial distribution of extinction features, leveraging recent advancements in coating and detector technologies for high throughput instruments in small form factors. The study outlines an instrument concept, observation strategy, and UV sky simulation for both balloon-based and small satellite-based platforms dedicated to the detailed exploration of UV extinction characteristics.