The Viscous Vacuum: Deep Space Telemetry and the 16/pi Drag Coefficient

For decades, the "Pioneer Anomaly"—a constant unmodeled deceleration of approximately 8.74 x 10^-10 m/s^2—has confounded standard orbital mechanics. While historically dismissed as thermal recoil, recent telemetry from the New Horizons mission suggests that deep space navigation requires continuous correction factors consistent with a physical drag. This paper serves as Flagship Paper #1 of the 16Pi Initiative. We demonstrate that this deceleration is not an error, but a direct measurement of Vacuum Viscosity. By applying the Kish Lattice Geometric Modulus (16/pi) to the Hubble Parameter (H0), we derive a precise drag coefficient that matches the observed Pioneer deceleration within experimental error bounds. Key Findings: Identification of "Lattice Grit" (g) as a non-zero vacuum friction. Correlation of Pioneer 10/11 and New Horizons drag signatures. Derivation of the "Hubble Friction" formula: a = c * H0 * (Geometry). Appendix: Includes the Python verification script (macro_vacuum_viscosity.py) visualizing the intersection of the Lattice Prediction and NASA telemetry.