Abstract: A three-mirror telescope having an ellipsoidal primary mirror, a hyperbolic secondary mirror, and an ellipsoidal tertiary mirror, with the three producing an image in a conveniently located finite plane for viewing.

Abstract: An automatic hybrid holograhic non-destructive testing (HNDT) method and system capable of detecting flaws or debonds contained within certain materials. This system incorporates the techniques of optical holography, acoustical/optical holography and holographic correlation in determining the structural integrity of a test object. An automatic processing system including a detector and automatic data processor is used in conjunction with the three holographic techniques for correlating and interpreting the information supplied by the non-destructive systems. The automatic system also includes a sensor which directly translates an optical data format produced by the holographic techniques into electrical signals and then transmits this information to a digital computer for indicating the structural properties of the test object. The computer interprets the data gathered and determining whether further testing is necessary, as well as the format of this new testing procedure.

Abstract: A velocity sensor for sensing the speed of a moving conductive body employing an E-shaped magnetic core having a pair of spaced Hall effect devices positioned on the end of the central core, the ends of all cores being arranged adjacent to the path of the moving conductive body. The difference in output voltage registered by the two Hall effect devices is indicative of the speed of the conductive body.

Abstract: Apparatus for cleaning contaminated surfaces such as hydro-carbon contaminant films in high vacuum environments including a plasma discharge housing for allowing a plasma to be generated in an environment having a higher pressure than the surface which is to be cleaned. A ground electrode and a radio frequency electrode partially surround a quartz plasma tube, for the introduction of an ionizable gas therein. These electrodes ionize the gas and help generate the plasma. This plasma flows through a non-constrictive aperture, through the plasma discharge housing and then on to the contaminated surface.

Abstract: A field effect transistor and method of making the same wherein a semi-conductor layer is placed on an insulating substrate, and wherein the gate region is separated from source and drain regions of a like conductivity type to that of the source and drain regions but of reduced conductivity, the gate electrode and gate region of the layer being of generally reduced length, and the gate region being of greatest length on its surface closest to the gate electrode. This is accomplished by initially creating a relatively large gate region of one polarity, and then reversing the polarity of a central portion of this gate region by ion bombardment, thus achieving a narrower final gate region of the stated configuration.

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 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 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: 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 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: 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.

Abstract: A vane-type internal combustion engine in which, during a power stroke, a spring is compressed which delivers back power to the engine during a non-powered stroke and provides relatively even torque.

Abstract: A device for tensioning test specimens within an hermetically sealed chamber. The device is characterized by a support column adapted to be received within an insulated, hermetically sealable chamber, a plurality of anchor pins mounted on the column for releasibly connecting thereto a plurality of test specimens, a plurality of axially displaceable pull rods received by the column in coaxial alignment with the anchor pins, one end of each pull rod being provided with a coupling for connecting the pull rod to a test specimen, while the opposite end of the pull rod is extended through a cover plate and adapted to be connected with a remotely related linear actuator through a connecting link including a load cell for measuring stress as the pull rod is placed in tension by the actuator.

Abstract: This invention relates to a solar appliance apparatus for utilizing solar thermal radiation to supply heat to a heating and cooking surface. The apparatus includes a housing permanently stationed inside a residential structure and the like. The housing contains a heat transfer medium and a radiation receiver carried in heat exchange contact with the medium. A heating and cooking surface is carried by the housing in heat exchange relationship with the heat transfer medium. A radiation pipe extends through the exterior wall of the building structure to deliver a concentrated beam of solar radiation rays to the radiation receiver.

Abstract: A mount for continuously orienting a collector dish relative to the sun in a system adapted to perform both diurnal and seasonal solar tracking. The mount is characterized by a rigid, angulated axle having a linear midportion supporting a collector dish, and oppositely extended end portions normally related to the midportion of the axle and received in spaced journals. The longitudinal axis of symmetry for said midportion of the axle is coincident with a seasonal axis while the axes of the journals are coincident with a diurnal axis paralleling the earth's polar axis. Drive means are provided for periodically displacing the axle about the diurnal axis at a substantially constant rate, while other drive means are provided for periodically indexing the dish through 1.degree.

Abstract: A notch filter for the selective attenuation of a narrow band of frequencies out of a larger band wherein a helical resonator is connected to an input circuit and an output circuit through discrete and equal capacitors, and a resistor is connected between the input and the output circuits.