The Boeing Company

Olin Corporation

Primex Technologies, Inc.

Paul G Lichon

Joseph P Morris

Donald Grim

Christopher H McLean

Philip O Flugstad

There is provided a system for the delivery of a gaseous product to a reaction chamber. The system includes a fuel tank containing a hypergolic liquid displaced from the fuel tank by a pressurized gas whose flow is controlled by a thruster control valve and directed to a gas generator. Pressurant gas entrained in the hypergolic liquid is not decomposed in the gas generator and causes pressure oscillations. The pressure oscillations are minimized by reducing the diameter of the gas bubbles or by disposing a gas fluid resistor between the gas generator and the reaction chamber.

Gaseous product delivery system

There is disclosed an anode for an arcjet thruster which resists erosion during start-up on constriction during steady-state operation. The anode includes a converging upstream portion, a diverging downstream portion and a constricted portion disposed therebetween. In one embodiment of the invention, rails formed in the constricted portion accelerate the passage of an arc during start-up reducing erosion. In a second embodiment, a higher strength material resists bulging as a result of the thermal gradient within the nozzle.

Arcjet anode

An ion thruster for accelerating positively charged ions produced by the collision of free electrons with gas atoms. An ion thruster (10,100) includes a cathode chamber (12, 60, 118) and an ionization chamber (14, 106). The outer surface of an emitter tube (28, 61, 128) is coated with a dielectric material to protect the emitter tube from sputtering erosion. A plurality of bar magnets (20, 22; 108, 110) are arranged in a spaced apart circular array around the cathode chamber with a pole face of each of the magnets tangentially aligned with wall sections (16, 18; 102, 104) of the ionization chamber. The bar magnets thus define a picket fence, wherein the magnetic field between adjacent bar magnets is used to extend the mean path of an electron entering the ionization chamber, improving the probability that it will impact an atom, creating an ion. A grid plate (112) comprises an accelerator grid (204) coated on its inner and outer surfaces with a dielectric coating (206, 208). The inner dielectric coating assumes the potential of the plasma, functioning as a screen grid, while the outer dielectric coating assumes the generally neutral potential of the plasma beam, functioning as a decelerator grid. The dielectric coatings on the accelerator grid protect it from sputtering erosion, and along with the dielectric coating on the interior surface of the ionization chamber provide thermal insulation, thereby improving the operating efficiency of the ion thruster.

Growing community of inventors

Bothell, WA, United States of America

Paul G Lichon