A casimir piezoelectric drive (CPD) architecture for supplementary MPD propulsion: a concept study

We propose a theoretical propulsion architecture in which the Casimir effect drives a mechanical see-saw oscillator that repeatedly impacts piezoelectric crystals, converting the resulting mechanical energy into electrical current. This harvested current is stored and used to power a magnetoplasmadynamic (MPD) thruster for interstellar space propulsion. The see-saw mechanism addresses a fundamental challenge of Casimir-piezoelectric harvesting: the piezoelectric effect requires changing mechanical strain, not static force, to produce continuous current. By alternating the Casimir-driven collapse of opposing plates onto piezoelectric elements, the architecture produces a repeatable cycle of charge generation. Onboard waste heat from the spacecraft’s radioisotope thermoelectric generator (RTG) provides the external energy input via thermal expansion of the see-saw beam, resetting the Casimir gaps after each impact; the Casimir force serves as the closing mechanism rather than the energy source. Temperature additionally serves a regulatory role via thermal corrections to optimize oscillation characteristics. Scaled across a large array of nanoscale Casimir gaps at the aft of the spacecraft, this framework is proposed as a candidate supplementary high-specific-impulse electric propulsion concept for interstellar missions. We outline the theoretical chain, present order-of-magnitude scaling analysis, identify key open questions and scaling constraints, and propose directions for future work. Experimental work has validated that piezoelectric elements can detect and respond to Casimir-scale forces, supporting the physical basis of this architecture. The architecture provides continuous supplementary MPD thrust for the operational lifetime of the onboard reactor without drawing from the primary power budget, limited only by propellant supply.