Design Blueprint: A Seismic Sensor Array for Newtonian-Noise Subtraction at a Gravitational-Wave Observatory: Sensor Count Computed from Coherence and Wiener Filtering

Design blueprint derived from the source paper (DOI 10.5281/zenodo.24150301): Newtonian noise — gravity fluctuations from moving mass in the ground and air — is the one noise source at a gravitational-wave observatory that cannot be shielded, only measured and subtracted. A subtraction array is designed here from coherence arithmetic: 200 seismometers per interferometer vertex, 600 in total, with a stated single-sensor coherence of 0.05 against the test-mass Newtonian noise 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.