Aerojet-general Corporation

Primex Aerospace Company

Aerojet Rocketdyne, Inc.

David Q King

Kristi H De Grys

Arnold W Voigt

Dennis L Tilley

Steven D Meyer

Roger M Myers

Justin M Pucci

Peter Y Peterson

Randall S Aadland

System () and methods () for testing a reaction thruster () in a vacuum environment. The methods comprise: disposing the reaction thruster in a vacuum chamber which is at least partially connected to earth ground; removing at least one gas from the vacuum chamber to provide the vacuum environment; operating the reaction thruster so as to create a beam of electrons; and/or electrically isolating the electrons of the beam from at least one electrically conductive surface of the vacuum chamber. The electrical isolation can be achieved by applying an electrical bias voltage to the beam via an electrode. The electrode may comprise a conductive object disposed in the vacuum chamber and/or at least a portion of a vacuum chamber wall. In all cases, the electrode is electrically isolated from a portion of the vacuum chamber that is connected to ground.

Ground based systems and methods for testing reaction thrusters

A system for uniformly distributing propellant gas in a Hall-effect thruster ( ) (HET) includes an anode ( ) and a porous material gas distributor ( ) (PMGD). The porous material ( ) may be porous metal or porous ceramic. Propellant gas is directed from a supply to the PMGD for distribution into a gas discharge region ( ) of the HET ( ). The gas flows through the porous material ( ) of the PMGD and out of the PMGD's exit surface ( ) into the annular gas discharge region ( ). The PMGD has an average pore size, pore density and thickness that are optimized to control the flow of the gas at the desired flow rate and distribution uniformity at a relatively short distance downstream from the PMGD. This feature allows HET to be short, significantly decreasing susceptibility to vibration problems encountered during vehicle launch. The PMGD can include a shield ( ) for preventing contaminants from traveling upstream from the gas discharge region from adhering to the porous metal. The shield may be integrated into the PMGD or be a separate shield. In addition, the shield may be perforated so as to allow gas to pass through the shield to further decrease the distance needed to achieve uniform gas distribution. Alternatively, the exit surface ( ) of the porous metal may be oriented to face perpendicularly from the gas discharge path out of the HET, which significantly reduces the probability of contaminants adhering to the exit surface.

Uniform gas distribution in ion accelerators with closed electron drift

A method and apparatus for using a magnetic field generated by a thruster magnet to control electron current emitted by a cathode assembly. The magnetic field reduces leakage current drawn by an inactive anode by producing a magnetic field in proximity to the inactive anode. This magnetic field increases the impedance to the anode for electron current which is produced in the cathode assembly. This reduction in leakage current reduces the amount of electron current produced by the cathode assembly. This control system can be implemented by connecting all thruster anodes and cathodes in parallel to an anode power supply.

Method and apparatus for magnetic voltage isolation

A series of long slats, preferably parallel and spaced apart uniformly, extend from a base plate to form a series of cavities between the slats for trapping high energy ions in the exit plume of an ion accelerator. The plume shield is designed to minimize escape of ions and sputtered atoms from the shield. The effectiveness of the shield in trapping and retarding ions and sputtered atoms can be accomplished by biasing the potential of the shield with respect to an adjacent structure and by inducing a magnetic field parallel to a target area of the shield, which can limit electron current to the target area.

Plume shield for ion accelerators

A specially designed magnetic shunt is provided encircling the anode region and/or annular gas distribution area of an ion accelerator with closed electron drift. The magnetic shunt is constructed to concentrate the magnetic field at the ion exit end, such that the location of maximum magnetic field strength is located downstream from the inner and outer magnetic poles of the accelerator. The specially designed shunt also results in desired curvatures of magnetic field lines upstream of the line of maximum magnetic field strength, to achieve a focusing effect for increasing the life and efficiency of accelerator. The anode of the accelerator can diffuse ionizable gas through a porous plate for an even distribution of the gas in the distribution area. Bias electrodes can be provided on the outer surfaces of the magnetic poles to control the voltages at specific locations between the anode and the cathode, and influence the shape of the magnetic field in addition to the location and direction of acceleration of the ions.

Multistage ion accelerators with closed electron drift

A specially designed magnetic shunt is provided encircling the anode region and/or annular gas distribution area of an ion accelerator with closed electron drift. The magnetic shunt is constructed to concentrate the magnetic field at the ion exit end, such that the location of maximum magnetic field strength is located downstream from the inner and outer magnetic poles of the accelerator. The specially designed shunt also results in desired curvatures of magnetic field lines upstream of the line of maximum magnetic field strength, to achieve a focusing effect for increasing the life and efficiency of accelerator.

Growing community of inventors

Woodinville, WA, United States of America

David Q King