X-ray dust echo tomography-A new era of Galactic exploration with AXIS (Sebastian Heinz) 

X-ray dust scattering can be a sensitive probe of the interstellar medium. While all bright X-ray sources in the Galactic plane exhibit diffuse dust scattering halos, highly variable sources can show spectacular dust echoes in the form of rings. Studying the temporal evolution of these rings has opened up the new field of X-ray dust tomography. Using a range of new techniques, such echoes allow us to probe dust mineralogy, constraint ISM composition (such as gas-to-dust ratios), and, perhaps most importantly, measure geometric distances. I will discuss why high angular resolution, large effective area, low particle background expected at LEO, and the ability to rapidly execute TOOs are crucial for pushing this field forward, and what it would mean for Galactic exploration.