Nuclear Microwave-Thermal Propulsion: Megawatt-Class NM with Rotating Electromagnetic Nozzles

Abstract

The capability gap between low-thrust electric propulsion and high-thrust chemical propulsion limits deep-space mission architecture. No current system achieves thrust ≥30 N, specific impulse ≥2,500 s, and power >1 MW simultaneously for crewed outer solar system transit. GNMT v7. 0 is a Nuclear Microwave-Thermal propulsion architecture resolving this gap through a megawatt-class nuclear electric system combining a Prometheus-lineage fast-spectrum fission reactor with twin Rotating Electromagnetic Nozzle (REMN) stacks. The REMN couples helicon radiofrequency plasma heating (13. 56–27. 12 MHz, η_RF = 0. 70–0. 85) with rotating permanent magnet nozzles (100–300 Hz), combining magnetic mirror thermal conversion (η_mirror = 0. 90–0.97) with J×B Lorentz acceleration to achieve η_noz = 0. 85–0. 92. At 1. 0 MW RF input and 1. 2 mg/s water propellant flow, exhaust velocity reaches 38 km/s (Iₛₚ = 3,880 s) and thrust is 46 N. A spine-mounted dual-use water-tank pod architecture provides directional crew radiation shielding (20–40 cm water-equivalent, GCR dose reduction 2–4×) and propellant storage, eliminating separate shielding mass and saving 20–30 tonnes. Mission analysis predicts Jupiter transit in 18–24 months (40–60% shorter than chemical), Saturn in 36–42 months, and Pluto in 48–60 months for a 100-tonne vehicle. All subsystems are grounded in validated laboratory physics; a four-phase validation pathway targets TRL.