nuSpaceSim: A Comprehensive Simulation for Modeling the Sensitivity of Space-based Experiments to the Detection of Cosmic Neutrinos using the Earth as the Neutrino Target

At high energies, cosmic neutrinos provide a clear window to view hadronic processes in astrophysical sources. Neutrino oscillations lead to an equal mixture of the three neutrino flavors at Earth in the cosmic neutrino flux, and tau neutrino interactions within the Earth provide a significant substantial flux of Earth-emergent tau-leptons for E_nu above ~ a PeV, thus turning the Earth into a multi-gigaton neutrino target. In their decay, tau leptons generate upward-moving extensive air showers (EAS) that can be detected using the observed optical Cherenkov and radio signals. nuSpaceSim is module-based, extremely fast end-to-end simulation package that models these physical processes and instrument response to determine the sensitivity to both the diffuse cosmic neutrinos and transient sources. NuSpaceSim provides a tool to both design the next generation of balloon- and space-based experiments as well as understand the data from recent experiments such as EUSO-SPB2 balloon-borne experiment and upcoming experiments including POEMMA-Balloon w/Radio (PBR) and Payload for Ultrahigh Energy Observations (PUEO). In this talk, the nuSpaceSim software, physics modeling, and the cosmic neutrino measurement capabilities of example sub-orbital and space-based experimental configurations will be presented.