The Ceiling Is the Contribution: A Saturation-Ceiling Beam Drive at the Knee

This paper carries one propulsion concept's full record, including the death of its first form. Concept A, an Einstein-Cartan spin-torsion thruster, was killed by its own numbers before any design work was spent on it: at the most generous input physics allows (solid-density, 100 %-polarised hydrogen), the torsion term's maximum thrust pressure is 2.057x10^-21 Pa — 1 N would need 4.862x10^20 m^2, a shortfall of 27.7 dex against an ordinary chemical chamber. It is closed, not parked, and its death is printed at full size. Concept B, originated in its place, is the Saturation-Ceiling Beam Drive: since a beam's thrust per watt T/P = beta/c saturates at gamma much greater than 1, while the corpus's counting saturation prints a proved ceiling at E_ind = 3.02x10^18 eV, the design sits at the knee, gamma = 10^3 (938 GeV protons), with the ceiling approximately 6.5 dex overhead as a proved margin: 3.336 N per GW, delta-v 10.53 km/s/yr on a 1.0x10^4 kg vehicle at 1 GW, propellant 3.51x10^-4 kg/yr, Isp 3.057x10^7 s, and an accelerator length of 31.2 km at 30 MV/m. The EeV variant at the ceiling itself is costed and dead — identical thrust, a 1.812x10^9 m accelerator. The limiting grade is printed on the paper's face, as the source package prints it: the corpus contributes the ceiling and the siting rule — not new thrust; Concept B's propulsion physics is standard relativistic beam mechanics carried to a complete design table. Four falsifiers are pre-registered (F-B1 to F-B4). Claim grade: DESIGN + SIMULATION ONLY — SIMULATED, NOT MEASURED. Defense Never List fence observed: civilian propulsion physics only. Program headline: vacuum catastrophe NOT SOLVED / PARTIAL, producing-count 0.