Air-breathing electrostatic ion thruster

#None.

#A. Field of the Invention

#The field of the present invention relates generally to propulsion systems that utilize charged particles to generate the propulsive forces to propel an object. More particularly, the present invention relates to ion thrusters that are adapted for use in the Earth's atmosphere. Even more particularly the present invention relates electrically powered, air-breathing ion thrusters capable of operating in low-Earth atmosphere.

#In the drawings which illustrate the preferred embodiments and the best modes presently contemplated for carrying out the present invention:

#FIG. 1 is cross-sectional side view of an air-breathing electrostatic ion thruster configured according to a preferred embodiment of the present invention showing atmospheric gas being drawn into the ionization chamber and accelerated ions being discharged therefrom to create thrust; and

#FIG. 2 is a schematic view of the electrical circuit for an air-breathing electrostatic ion thruster configured according to a preferred embodiment of the present invention.

#With reference to the figures where like elements have been given like numerical designations to facilitate the reader's understanding of the present invention, the preferred embodiments of the present invention are set forth below. As will be readily understood by those skilled in the art, the enclosed figures and drawings are merely illustrative of a preferred embodiment and represents one of several different ways of configuring the present invention. Although specific components, materials, configurations and uses are illustrated, a number of variations to the components and to the configuration of those components described herein and in the accompanying figures can be made without changing the scope and function of the invention set forth herein. For instance, although the figures and description provided herein are directed to a generally cylindrical housing having certain materials and arrangement of components, those skilled in the art will readily understand that this is merely for purposes of simplifying the present disclosure and that the present invention is not so limited.

#An air-breathing electrostatic ion thruster that is manufactured out of the components and configured pursuant to a preferred embodiment of the present invention is shown generally as 10 in the figures. Ion thruster 10 generally comprises a housing 12 having a first or forward end 14, a second or rearward end 16, an electrically conductive inner surface 18 and an electrically non-conductive outer surface 20, as shown in FIG. 1. In a preferred embodiment, housing 12 will be made out of a generally lightweight material that has its interior coated with a conductive material to form inner surface 18 and its exterior coated with a non-conductive/insulating material to form outer surface 20. In an alternative embodiment, both inner 18 and outer 20 surfaces are formed from separate cylindrically shaped shells that are joined in abutting relation, with the inner shell, defining inner surface 18, disposed symmetrically within the outer shell, defining outer surface 20, to substantially provide an integral housing 12 having an inner conductive layer and an outer non-conductive layer. Preferably, inner surface 18 will be formed from a metallic material that is known to be highly conductive, such as brass, aluminum, magnesium, copper or like materials. Conversely, outer surface 20 should be formed from an electrically non-conductive, insulating material such as plastic or nylon, with materials such as Delrin, a trademark of DuPont, or the like being preferred due to its resistance to high voltage and high temperature breakdown. Inner surface 18 defines an ionization chamber 22 having an inlet 24 at the forward end 14 of housing 12 and an outlet 26 at the rearward end 16. As explained in more detail below, ambient atmospheric gas 28 is received through inlet 24 and is ionized in ionization chamber 22, with inner surface 18 functioning as an anode (a cylindrical anode in FIG. 1), to discharge accelerated ions 30 through outlet 26 at the rearward end 16 of housing 12 so as to create thrust to propel a vehicle (not shown) utilizing ion thruster 10 of the present invention.

#Positioned inside inlet 24, generally at or near forward end 14 of housing 12 and attached thereto, is forward screen electrode 32. In one embodiment, forward screen electrode 32 has a plurality of spaced apart electrically conductive metallic wires or members 34 that define a plurality of forward screen apertures 36 of sufficient size to easily permit atmosphere gas 28 to pass therethrough into ionization chamber 22. Alternatively, forward screen electrode 32 can be other screen or screen-like devices, such as a plate having the plurality of forward screen apertures 36. As explained below, however, the wires or other electrically conductive members 34 forming forward screen electrode 32 must have sufficient surface area to apply an electrical charge thereto. As will be clearly understood by those skilled in the art, a variety of different configurations are possible for forward screen electrode 32, including a typical screen configuration having square, rectangular, circular or oval apertures 36 or formed from metallic or other electrically conductive wires or members 34 that are joined together in a manner that provides sufficient gaps for apertures 36 (i.e., slits or slots similar to blinds, etc.). Positioned inside outlet 26 generally at or near rearward end 16 of housing 12, and attached thereto, is rearward screen electrode 38 having rearward screen apertures 40 and accelerator electrode (or grid) 42 having accelerator apertures 44. As shown in FIG. 1, accelerator electrode 42 is positioned rearward of and in spaced apart relation to, although generally close to, rearward screen electrode 38 in a manner such that the rearward screen apertures 40 are aligned with accelerator apertures 44. As with forward screen electrode 32, the apertures 40 and 44 of both rearward screen electrode 38 and accelerator electrode 42 can be defined by a plurality of metallic wire or other electrically conductive members, shown as 46 and 48, that provide sufficient surface area to apply an electrical charge thereto (alternatively it can be other screen or screen-like devices, such as a plate having the plurality of rearward screen apertures 40). The apertures 40 and 44 of rearward screen electrode 38 and accelerator electrode 42, respectively, should be sufficiently sized and configured to permit the flow of charged, accelerated ions 30 to generally pass therethrough. The function of forward screen electrode 32, rearward screen electrode 38 and accelerator electrode 42 in ion thruster 10 of the present invention is explained below.