Next generation gravitational wave (GW) detectors will soon initiate precision tests of GR at large distances. Current observations have put constraints on the graviton mass outside our solar system with future detectors reaching redshifts 10 and above. In various viable massive graviton theories the massive carriers for gravitational interactions can be screened within galaxy distributions due to its curvature. This occurs through the Vainshtein screening mechanism which could also explain null results within our solar system. Screening also holds for GWs with beyond-GR effects suppressed within a given radius. Here detectors like Cosmic Explorer will allow accurate observations at vast scales to probe this screening effect. This talk will discuss a framework for next generation detectors, i.e., Cosmic Explorer, to probe fundamental physics in GW propagation screened by multiple galaxy distributions. Using realistic galaxy population models the constraint on the graviton mass and screening radius will also be discussed.
