We will report on the development of the Lunar Occultation Explorer (LOX), an Explorer-class astrophysics mission based on the Lunar Occultation Technique (LOT). This new astronomical protocol has recently been validated in-situ from lunar orbit, and leverages the Moon as a platform for nuclear astrophysics. The primary science goals of LOX are focused on Type-Ia supernovae, including a census and categorization of their progenitor populations, fundamental characterization and tests of the cosmological standard candle hypothesis, and detailed evaluation of the lifecycle of matter and energy in our Galaxy and beyond. We will present details of the LOX mission design, including primary science drivers, preliminary mission sensitivity estimates, and implementation trades. Our development program is focused on realizing the first high-energy astrophysical investigations using the Moon as a scientific platform in an effort to provide unique, achievable, and cost-effective next-generation capabilities in nuclear astrophysics.