Understanding the nature of dark energy is at the core of DOE’s High Energy Physics mission. The Large Synoptic Survey Telescope (LSST), a ten-year imaging survey starting in 2022, is a cornerstone of the U.S. cosmological community’s efforts to understand dark energy, the cause of the accelerated expansion rate of the Universe. The Dark Energy Science Collaboration (DESC), an international collaboration with more than 800 members, was formed specifically to prepare to study dark energy with LSST. A key part of the preparation for LSST data arrival involves making sure that we can properly correct for systematic uncertainties due to astrophysical and observational nuisances, and therefore fully take advantage of the exquisite statistical constraining power of the data to measure dark energy with percent-level precision. Building on established simulation infrastructure, planned upgrades in features and performance are expected to enable us to reach the ~1000 square degree scale, a factor of ~3 beyond what is currently possible. 

The resulting dataset and associated databases produced will be documented and made available (on request) to the wider LSST science community, thus enabling a broader range of science cases. The infrastructure improvements that are developed for this simulation campaign are part of the longer path to science readiness undertaken by the LSST DESC.