PPTs are electromagnetic propulsion devices which store electrical energy in a capacitor to periodically form a high current arc discharge across the propellant (typically Teflon). The energy of the arc vaporizes or ablates the propellant, thus creating an ionized gas which is subsequently accelerated out of the channel to high velocities by the Lorentz force.

 Main subsystem involved in the L-uPPT development are showed in the next figure: