The formation and fate of stratospheric N2O5 influences the total reactive nitrogen (NOy) budget. Heterogeneous (gas / particle) processing of N2O5 transfers Nitrogen Oxides (NOx) into HNO3 (a long-lived NOx reservoir) or nitryl chloride (ClNO2, a source of Cl radicals) which in turn influence stratospheric ozone (O3) destruction. Yet, the N2O5 uptake coefficient (gamma) of stratospheric aerosol has yet to be directly constrained by stratospheric observations and understanding of this parameter is instead based on laboratory and upper-tropospheric field studies. As such, there is uncertainty in global climate models with respect to N2O5 influences and how future changes in stratospheric aerosol might couple to ozone chemistry. In 2023 the NOAA Stratospheric Aerosol Processes, Budget, and Radiative Effects (SABRE) campaign achieved comprehensive observations of stratospheric gasses and aerosol from the NASA WB-57 high-altitude research aircraft. Here, we combine in-situ stratospheric observations from SABRE collected north of Alaska (latitudes between 60 – 80 degrees and altitudes between 10 – 17 km) with an iterative diel box model to determine gamma(N2O5). The determined gamma(N2O5) values range primarily between 10^–3 – 10^–1. Preliminary results show strong positive correlations between gamma(N2O5) and aerosol sulfate mass fraction. Conversely, there is a negative relationship with aerosol containing biomass burning markers. Overall, gamma(N2O5) values are consistent with upper-troposphere determinations but are slower than parameterizations used for pure sulfate aerosol commonly used in stratospheric models. Considerations of ClNO2 yields and aerosol properties will also be presented.