The Artemis-enabled Stellar Imager (AeSI) Mission Concept NASA's return to the Moon for the long-term offers significant opportunities to take practical steps towards high-impact scientific capabilities. One candidate is extremely high-resolution interferometric imaging at visible and ultraviolet wavelengths. The AeSI Team, with support from the NASA Innovative Advanced Concepts (NIAC) Program, is therefore examining the feasibility of building an UV/Optical interferometer, named the Artemis-enabled Stellar Imager (AeSI), on the lunar surface. This observatory can resolve the surfaces of stars, probe the accretion disks surrounding nascent stars and black holes, and begin the technical journey towards resolving surface features and weather patterns on the nearest exoplanets. A lunar interferometer has advantages over Earth-based facilities: longer coherence times (instrumentally driven 10-100+ seconds vs. the atmospheric limit of a few milli-seconds!) mean higher sensitivity, the vacuum environment requires a simpler infrastructure (e.g., delay lines need not be enclosed), and observations can be obtained at UV wavelengths not accessible to the ground. It also has advantages over a space-based free-flyer by enabling flexible station keeping while eliminating the need to develop millimeter-level-accuracy free-flying. A fully developed facility will be large, but it could be built and deployed in stages. For our Phase I NIAC design we chose to start with a 15-element elliptical array with a major axis of up to 1-km that could later be expanded to 30-elements in one or more stages, though we could start with as few as 7-elements if the situation required. Whatever our starting configuration, the baselines and the number of telescopes can be increased, and larger telescopes can be inserted, as desired. Each of these upgrades can be accomplished with minimal disruption of the rest of the system.