Dual Hybrid Plasma Source (DHPS Thruster™): Helicon-ECR Synergy and Off-Mode Resilience for Small Orbital Logistics Vehicles Transport

The rapid expansion of commercial low-Earth-orbit (LEO) logistics demands propulsion systems that deliver high thrust for rapid ascent while maintaining exceptional efficiency and reliability during orbital maneuvers. This work introduces a dual hybrid engine architecture that combines an advanced solid chemical stage (MnB2-enhanced APCP, Isp ≈ 310–330 s) with a novel permanent-magnet Hybrid Plasma Source (HPS) thruster (helicon + ECR, Isp up to 2663 s) for ultra-rapid single-orbit cargo delivery (∼ 90–120 min point-to-point). The HPS employs a modular quartz chamber with 13.56 MHz RF helicon excitation and 2.45 GHz ECR enhancement, confined by temperature-stable SmCo magnets (200–1000 G), achieving plasma densities exceeding 1015 cm−3 in hybrid mode and enabling thrust levels of 184–1242 mN at 1–3.5 kW input power. A comprehensive 81-run 34 full-factorial Design of Experiments (DoE) was conducted to map performance across nominal hybrid, helicon-only, ECR-only, and no-excitation off-modes. Results demonstrate strong synergistic density jumps in hybrid operation (mean thrust 563 mN, efficiency 135 mN/kW) and robust fault tolerance: helicon-only retains ∼ 78% of hybrid thrust (mean 441 mN, Isp 2074 s) and exceeds the 1013 cm−3 target density, while ECR-only provides a viable low-power fallback (mean 57 mN, Isp 1771 s). Thrust and efficiency scale positively with magnetic field strength and total power, with flow rate providing linear amplification. This bimodal design offers significant advantages over conventional chemical or pure electric systems: reduced propellant mass fraction, graceful degradation under subsystem failure, and precise geodesic deorbit capability for parachute cargo recovery. The technology is positioned as an enabling platform for next-generation small orbital logistics vehicles, with near-term applicability to high-value time-sensitive cargo missions and long-term potential for scalable micro-launcher constellations.