Propulsion apparatus (10) for space vehicles, comprising a solid state oxygen-rich source layer (11), means (12) for extracting oxygen from said solid state oxygen-rich source layer (11), means (16, 14, 17) for accelerating correspondingly extracted oxygen ions into vacuum. According to the invention, it comprises a stack including said solid state oxygen-rich source layer (11), an active layer (16) being deposited above said solid state oxygen-rich source layer (11), in contact with said solid state oxygen-rich source layer, said active layer (16) being formed with a material different from said solid state oxygen-rich source layer (11), said material being an oxide presenting impedance hysteresis behavior, i.e. a memristor, wherein in a low resistance state oxygen ions (22) are expelled through the active layer (16) and wherein in a high resistance state the active layer (16) ceases expelling oxygen ions (22)
