This thesis presents the development and deployment of an integrated multiscale-multiphysics model for pure-ion emission electrospray ionic-liquid ion sources. The primary contribution of this work is to maintain physics informed boundary conditions and model parameters across all temporal and spatial scales from the nanoscale to the spacecraft scale. The goal is to provide an operating condition agnostic framework capable of modeling ion sources at operating points relevant to both individual emitter and full array applications. A continuum fluid electrohydrodynamic model is used to generate initial conditions for particles generated from electrically assisted evaporation. These particles are propagated through a single emitter particle model capable of directly resolving the electrostatic interparticle forces, solvated cluster dissociation events, and particle collisions in order to predict single emitter performance. The results for this model are temporally aggregated to produce injection distributions for meter-scale array simulations to investigate intra-beamlet interference, beam divergence, and space-craft plume interactions. The integrated model permits sensitivity analyses of key metrics, supporting the optimization of geometric and operating conditions to enhance measurable system performance, calibration of the model to experiment, and the investigation of manufacturing defects.