M.U.L.A.N.: Thermodynamically Consistent Propellantless Propulsion via Asymmetric Nanoconfinement, Covalent Strain, and Optical Upconversion

We present a fully thermodynamically consistent propellantless thrust concept based on theasymmetric nanoconfinement and mechanical pre-straining of polar molecules (H2O) withina refractory plasmonic lattice. The MULAN (Momentum Uplifting via Light Amplificationin Nanoconfinement) v3 engine bypasses fast vibrational relaxation (1–2 ps) by utilizing amechanical-optical pumping scheme. The architecture introduces a three-stage cascade: nearinfrared (NIR) input photons are frequency-shifted via upconversion microspheres, routedthrough a unidirectional nano-hollander (photonic diode), and injected into geometricallyconstrained, pre-strained O-H covalent bonds. Thermal fluctuations from a hot refractoryreservoir (Ta4HfC5, Tmelt ≈ 4200 K) continuously recharge the bond strain. Spatialasymmetry is enforced via a passive photonic nano-collet, forcing highly directional photonemission. Momentum conservation is preserved, but a dimensionless amplification coefficientK =pout/pin > 1 is enabled via thermal assistance without violating the second law ofthermodynamics. At a spacecraft power level of 30 W and active areas above 0.13 m2, MULANv3 provides a scalable, multi-decade propellantless propulsion alternative to conventional ionthrusters.