Designing and building a UAV for Drone-based optical calibration of the POEMMA Balloon with Radio's Hybrid Fluorescence/Cherenkov Telescope

We present the design and development of a UAV-based calibration platform for the Pathfinder mission for NASA's Probe Of Extreme Multi-Messenger Astrophysics (POEMMA) program, POEMMA Balloon with Radio (PBR). The UAV, equipped with a UV LED flasher, a steady-state light source, a MHz radio pulser, and a GPS receiver, serves as a versatile tool for calibrating the mission's Radio/Cherenkov/Fluorescence telescopes. This platform aims to ensure accurate alignment of telescope optics across the entire field of view, test the Cherenkov trigger response to known signals, and validate the telescope's Radio-to-Cherenkov and Cherenkov-to-Radio trigger algorithms. The drone's autonomous operation capabilities allow for calibration flights lasting 30-60 minutes, providing reliable data to fine-tune the telescopes' performance. This contribution will include the UAV design and performance, details on the instrument payload development, and plans for future calibration missions.