Abstract: A method and apparatus for reconditioning batteries utilizing a DC-DC converter. During a discharge of the batteries, each cell is monitored by the converter. When the voltage of a cell decreases to a predetermined level, a converter will assume the load of this cell and inhibit the voltage from reaching zero, thereby preventing voltage reversal of that cell.

Abstract: A system for tethering one orbiting space vehicle to another in which a tetherline between the vehicles is controlled by a motorized reel which in turn is controlled to deploy, retrieve, or maintain a constant line length while effecting a stabilizing influence on the line. This is accomplished by applying a tension to the line which takes into account the instantaneous length of the line, rate of change of the length of the line, and certain constants which vary depending upon the mode of operation, deployment, retrieval, or station keeping.

Abstract: A recognition system for robots is responsive to encoded information from a plurality of sources for enabling a robot to recognize and identify the sources. A receiver located on the robot detects incoming signals and decodes them. The decoded signal is compared with information stored in the robot memory to provide source identification. A direction determining sub-system incorporated into the receiver provides source direction information. The system may utilize either digital or analog techniques.

Abstract: An improved apparatus for examining the crystal lattice of a semiconductor wafer utilizing x-ray diffraction techniques. The apparatus is employed in a method which includes the step of recording the image of a wafer supported in a bent configuration conforming to a compound curve, produced through the use of a vaccum chuck provided for an x-ray camera while the entire surface thereof is illuminated simultaneously by a beam of incident x-rays which are projected from a distant point-source and satisfy conditions of the Bragg Law for all points on the surface of the wafer.

Abstract: A sprayable, low density ablative composition consisting essentially of:A. 100 parts by weight of a mixture of 25-65% by weight of phenolic microballoons,0-20% by weight of glass microballoons,4-10% by weight of glass fibers,25-45% by weight of an epoxy-modified polyurethane resin,2-4% by weight of a bentonite dispersing aid and1-2% by weight of an alcohol activator for the bentonite;B. 1-10 parts by weight of an aromatic amine curing agent; andC. 200-400 parts by weight of a solvent.

Abstract: Porous copper workpieces are obtained byA. obtaining a copper workpiece having a selected grain size;B. machining the workpiece to a selected size and shape;C. electrochemically polishing said workpiece;D. annealing said workpiece from step (c) in oxygen at a temperature from 750.degree. to 1080.degree. C. and a pressure of 10.sup.-4 - 10.sup.2 Torr; andE. annealing said workpiece from step (d) in hydrogen.

Abstract: A wrist joint assembly is provided for use with a mechanical manipulator arm for finely positioning an end-effector carried by the wrist joint on the terminal end of the manipulator arm wherein the wrist joint assembly is pivotable about a first axis to produce a yaw motion, a second axis to produce a pitch motion, and a third axis to produce a roll motion, wherein the three axes are mutually perpendicular and have a common point of origin. The wrist joint assembly includes a disk segment affixed to the terminal end of the manipulator arm and a first housing member rotatably carried on the disk segment about the first axis. A second housing member is rotatably carried on the first housing member and a third housing member is rotatably carried on the second housing member whereby the third housing member and the mechanical end-effector carried thereon are moved in the yaw, pitch, and roll motion.

Abstract: A projection system for the display of parallax and perspective of a real image from a hologram in which a reference beam is projected in a sequence of several projections at selected angles of perspective through the hologram, this sequence being rapidly performed. The resulting angular spaced images emitting from the hologram are directed onto a mirror which is coordinately tilted to reflect all of the resulting images in register onto a screen where they appear as a single three-dimensional image.

Abstract: Apparatus for testing a glancing-incidence mirror system for an X-ray telescope, wherein the system has an even number of coaxial and confocal reflecting surfaces, includes an X-ray laser for generating a collimated beam of X-rays directed along the axis of the system so that the beam is incident on the reflecting surfaces and illuminates a predetermined area thereof. An X-ray detector, such as a photographic film, is located at the common focus of the surfaces so that the image thereon produced by the X-rays will provide a measure of the resolution and efficiency of the system.

Abstract: A drift compensated and intensity averaged extensometer for measuring the diameter or other properties of a substantially cylindrical sample based upon the shadow of the sample. A beam of laser light is shaped to provide a beam with a uniform intensity along an axis normal to the sample. After passing the sample, the portion of the beam not striking said sample is divided by a beam splitter into a reference signal and a measurement signal. Both of these beams are then chopped by a light chopper to fall upon two photodiode detectors. The resulting AC currents are rectified and then divided into one another, with the final output being proportional to the size of the sample shadow.

Abstract: A superconducting microbridge is provided for use in superconducting quantum interference devices wherein a pair of spaced layers of superconductive material are connected by a weak link bridge to establish an electrical junction. The superconductive layers and bridge are coated with a semiconductor material shunting the bridge at room temperatures to prevent the destruction of the device by minute electrical currents while the coating acts as a dielectric permitting normal electrical behavior of the microbridge at cryogenic temperatures.

Abstract: A semiconductor projectile impact detector for use in determining micrometeorite presence as well as its flux and energy comprises a photovoltaic cell which generates a voltage according to the light and heat emitted by the micrometeorites upon impact with the cell. A counter and peak amplitude measuring device are used to indicate the number of particules which strike the surface of the cell as well as the kinetic energy of each of the particles.

Abstract: A power factor control system for use with AC induction motors which samples line voltage and current through the motor and decreases power input to the motor proportional to the detected phase displacement between current and voltage to thereby provide less power to the motor, as it is less loaded.

Abstract: The method of refining, or growing, bulk single crystals in which the base material is suspended, positioned, and shaped as a containerless melt by wetting forces in an environment substantially free of gravity.

Abstract: A real time reflectometer with the particular utility of measuring fairly rapid (transient) changes in the specular reflectance of a sample which is continuously exposed to a perturbing environment containing a fixed radiation source, a fixed detector, a uniformly rotating sample wheel and a uniformly rotating optical wheel. The plane of rotation of the sample wheel and the optical wheel are normal to one another, and the gear drives of both wheels are interconnected and are driven by a single drive motor thereby insuring the alignment of the mirrors contained on the optical wheel with the sample present on the sample wheel. The radiation source generates light directed toward the uniformly rotating sample wheel, said sample wheel containing a test sample and an aperture. Light reflected off the test sample is also reflected from the optical wheel and directed toward the detector.

Abstract: A tachometer in which sine and cosine signals responsive to the angular position of a shaft as it rotates are each multiplied by like, sine or cosine, functions of a carrier signal, the products summed, and the resulting frequency signal converted to fixed height, fixed width pulses of a like frequency. These pulses are then integrated, and the resulting DC output is an indication of shaft speed.

Abstract: An improved accumulator particularly adapted for use in controlling the pressure of a stream of fluid in its liquid phase utilizing the fluid in its gaseous phase. The accumulator is characterized by a shell defining a pressure chamber having an entry throat for a liquid and adapted to be connected in contiguous relation with a selected conduit having a stream of fluid flowing through the conduit in its liquid phase. A pressure and volume stabilization tube, including an array of pressure-relief perforations is projected into the chamber with the perforations disposed adjacent to the entry throat for accommodating a discharge of the fluid, in either gaseous or liquid phases, while a gas inlet and liquid to gas conversion system is provided for the chamber and connected with a source of the fluid for continuously pressurizing the chamber for controlling the pressure of the stream of liquid.

Abstract: Zinc orthotitanate (Zn.sub.2 TiO.sub.4) suitable for use as a pigment for spacecraft thermal control coatings is prepared by heating a slightly zinc-deficient reaction mixture of precipitated oxalates of zinc and titanium. The reaction mixture can be formed by co-precipitation of zinc and titanium oxalates from chloride solution or by mixing separately precipitated oxalates. The mixture is first heated to 400.degree. to 600.degree. C to remove volatiles and is then rapidly heated at 900.degree. to 1200.degree. C. Zinc orthotitanate produced by this method exhibits the very fine particle size needed for thermal control coatings as well as stability in a space environment.

Abstract: A method for measuring stress in test articles including the steps of obtaining for a calibrating specimen a series of transit time differentials between the second wave echo for a longitudinal wave and the first wave echo for each of a pair of shear waves propagated through the specimen as it is subjected to a known stress load of a series of stress loads for thus establishing a series of indications of the magnitudes for stress loads induced in the specimen, and thereafter obtaining a transit time differential between the second wave echo for a longitudinal wave and the first wave echo for each of a pair of shear waves propagated in the planes of the stress axes of a test article and comparing the transit time differential thus obtained to the series of transit time differentials obtained for the specimen to determine the magnitude of biaxial stress in the test article.

Abstract: A pressure-shaped reflector apparatus is provided for collecting and concentrating electromagnetic radiation waves and the like. The apparatus can be used, among other things, for concentrating solar radiation waves to provide an alternate source of energy. The apparatus includes an upper cylindrical hoop member, a lower cylindrical hoop member and a plurality of vertical strut members carried between the upper and lower hoop members spacing the hoop members apart. A resiliently deformable enclosure is carried between the upper and lower hoop members having an upper reflective surface co-extensive with the upper hoop member. As air is evacuated from the interior surface of the enclosure the upper reflective surface deforms inwardly providing a reflective surface of spherical curvature having high specular reflection properties.