Mergers of ultra-compact stellar remnants called neutron stars have now been observed. They provide new tools to study general relativity, compact objects, neutron star equation of state, plasma physics, astrophysical jet physics, and nucleosynthesis. A joint US-Israeli research team will develop numerical simulations of binary mergers through their full development. The US effort is jointly led by California State University, Sacramento, Purdue University, and Northwestern University. The team will aim to construct “meter-to-parsec” models of binary mergers, which follow through the entire journey of length and time scale, by directly connecting the pre-merger state of a neutron star - neutron star (NS-NS) or neutron star - black hole (NS-BH) binary to the regions where the observed photons are produced. This project has two main broader societal impacts : (i) Development of a globally competitive STEM workforce; and (ii) Improvement of STEM education of K-12 students. The models will allow interpretation of various observables of the system by connecting them with the conditions inside the ejecta and in the pre-merger phase: (i) Generating consistent models of the jet profile will allow the researchers to connect the observed off-axis emission to the conditions at the base of the jet and help construct reliable emission models for the multi-wavelength counterparts of gravitational wave events. (ii) To date, it is still not known if the compact merger remnants powering s