Nanopropulsion from High-Energy Particle Beams via Dispersion Forces in Nanotubes

Abstract

Here we show for the first time that the van der Waals forces which act on the inner cores of multiwalled nanotubes can be altered to produce high-energy, high-luminosity neutral beams of nano-shuttles sliding inside the outer shells until they are ejected. This novel principle of nanotube core acceleration is based on a nanoscale implementation of dispersion force manipulation originally introduced and then developed both theoretically and experimentally by the author in micro-electromechanical systems (MEMS). In analogy with electromagnetic neutral particle acceleration, the van der Waals force, which has been experimentally observed to "retract" partially extruded cores inside the outer nanotube shells at extremely high speeds, is modulated in order to transfer a net amount of kinetic energy to the accelerated beam. Since dispersion forces are a dominant interaction at typical interlayer distances ≈ 0.34 nm, and sliding frictional forces are relatively small, the resulting final speed of the ejected shells can exceed vcore,fin 10 km/s. Technologies for the synthesis, fabrication, and uncapping of dense arrays of parallel, telescoping, multiwalled nanotubes have been already demonstrated to yield surface densities 10 10 cm −2 and individual nanotube lengths 10 cm have been demonstrated. Therefore, as the technology becomes fully developed, the resulting net thrust and specific impulse of a nanopropulsion device based on this approach can be shown to decisively exceed that of other existing lowthrust technologies. Additional advantages include the neutrality of ejecta, the potential for a tight integration of the propulsive system with on-chip digital management, and system versatility to accommodate drastically different mission profiles.