Abstract: An inexpensive, reliable, accurate, high speed powder dispensing apparatus is disclosed which includes a barrel for transferring powder from a first retainer to a second retainer. The barrel is vibrated to cause the powder to translate on a surface thereof. The vibration is controlled to cause a measured amount of powder to be dispensed. In a specific embodiment, two barrels are included to provide coarse and fine rates of powder dispensation. A specific embodiment includes a scale for weighing the discharged powder. The scale is equipped with a sensor, the output of which is used to control and limit the rate of powder flow up to a preselected amount. An additional novel feature of the invention is the use of a mechanism to assist in overcoming the inertia of the scale.The invention provides an inexpensive, reliable, accurate, high speed powder dispensing apparatus. As the need to rotate barrels of the prior art is eliminated, the likelihood of occasional jamming is minimized.

Abstract: A fluid filter element, filter, and process for its fabrication, wherein the filter element includes a flat base and a thin layer deposited thereupon having a pattern of channels through which a fluid may flow. In operation, the element is pressed against a flat surface, preferably the back side of another element in a stack of filter elements, whereupon the channels become closed conduit. The channels have a minimum dimension of the thickness of the layer, so that larger particles may not pass therethrough. Fabrication of the thin layer with the channels therein is preferably accomplished by masking a pattern corresponding to the channels and then vapor depositing the remainder of the thin layer, as masking and deposition permits accurate control of the height of the deposited layer, and, then, the minimum dimension of the channels.

Abstract: A solar cell array utilizing geometrically alternating, laterally disposed N-on-P and P-on-N gallium arsenide solar cells is disclosed. Improved array efficiency is achieved by placing adjacent solar cells in substantial contact with each other and eliminating bus connections on the top surfaces. This is accomplished by providing the solar cells with a lateral cross-sectional configuration of a parallelogram with the N-on-P solar cells slanted in one lateral direction and the P-on-N solar cells slanted in the opposite direction. The top surfaces of adjacent, contacting solar cells are electrically connected by extending a connector grid across the top surfaces. Strip connectors are used to join the bases of adjacent solar cells.

Abstract: A solar cell generates an electrical voltage with contributions from both photovoltaic and thermoelectric effects, when a high thermal gradient is impressed across a semiconductor p/n solar cell. To achieve a substantial thermoelectric voltage contribution, the front side of the solar cell is heated to an elevated temperature consistent with efficient operation of the photovoltaic mechanism of the solar cell, and the back side of the solar cell is cooled to a lower temperature. The magnitude of the thermoelectric voltage contribution is increased by reducing the coefficient of thermal conductivity of the solar cell material, by using face electrodes having the proper thermoelectric potentials in contact with the solar cell material, by increasing the light intensity and then the heat input to the front side of the solar cell, and by cooling the back side of the solar cell.

Abstract: A process for fabricating layered semiconductor structures, particularly thin gallium arsenide solar cells, on reusable substrates. The structure is fabricated by depositing a selectively removable layer such as gallium aluminum arsenide onto a substrate, and then depositing a solar cell basic structure on the selectively removable layer. Preferably, the solar cell basic structure includes a layer of p-type gallium arsenide on the layer of gallium aluminum arsenide, a layer of n-type gallium arsenide on the p-type gallium arsenide, and a transparent glass cover over the n-type gallium arsenide layer. The solar cell basic structure is separated from the substrate by selectively dissolving the gallium aluminum arsenide layer, and a new layer of gallium aluminum arsenide is epitaxially deposited upon the exposed face to form a thin, lightweight gallium arsenide solar cell. If the layer of p-type gallium arsenide is about 0.5 microns thick or less, the new layer of gallium aluminum arsenide may be omitted.

Abstract: Hydrazine thruster 10 is mounted on support flange 14 with thermal mass 12 therebetween. The thermal mass 12 extracts sufficient heat so that the incoming hydrazine in inlet line 20, as well as that portion of the decomposition catalyst contained within the inlet portion of chamber housing 24, is maintained at a temperature below the hydrazine saturation temperature at the pressure within chamber housing 24 so that at any on/off operating duty cycles for that installation, the hydrazine is discharged into the catalyst in chamber housing 24 as liquid.

Abstract: Hydrazine thruster 30 minimizes impulse bit degradation by making the hydrazine more reactive with the catalyst 66 by using higher temperature hydrazine and smaller catalyst grain, and also concentrates the injected hydrazine in smaller catalyst volume 66 so that heat released aids decomposition of a greater quantity of injected hydrazine.

Abstract: Specific impulse of hydrazine thruster is augmented by electrothermally heating the hot gas in heater passages 36 and 37 as it passes from hydrazine dissociation chamber 14 to thrust nozzle 28. Tubular ceramic electric resistance heater 31 performs primary heating. Specific impulse can be raised from 230 to 300 seconds.

Abstract: Stacked plates each have a plurality of thin etched flow passages to be employed in a tank containing gas and liquid for separation to provide gas free liquid. The liquid surface tension in the flow passages that are exposed to the gas provides a force to prevent the gas from entering the liquid galleries until the tank is void of liquid. Such separation is useful in fuel tanks in near zero gravity environment as well as in other separation duties.

Abstract: Monopropellant thruster has liquid hydrazine distribution nozzles of such structure as to direct streams of liquid hydrazine into hydrazine decomposition catalyst without puddling and without impinging thruster walls. Thruster also has screens to separate the dissociation catalyst into zones to prevent catalyst voids from standing adjacent distributor nozzles.