Design Blueprint: A Three-Thousand-Square-Kilometre Cosmic-Ray Surface Array: Aperture, Station Count and Event Rates Computed from the Flux

Design blueprint derived from the source paper (DOI 10.5281/zenodo.24150256): A ground array for ultra-high-energy cosmic rays is designed from the flux it must harvest: 1,540 water-Cherenkov stations on a 1.5 km triangular grid cover 3,000 square kilometres and present a geometric aperture of 8,482 square kilometres steradians for showers within 60 degrees of zenith. At adopted integral fluxes the array records about 170 events per year above 10 EeV and 55,983 per year abo Status: DESIGN BLUEPRINT — SIMULATED, NOT MEASURED — NOT BUILT. All numbers are simulated values from the source paper's computation, deposited with this blueprint as compute.py and results.json. AI-use disclosure: Dave, an AI research system, assisted with the computation and drafting under the author's direction; author of record William Alexander Aldred.