Abstract: In an optical radar system a coherent signal is transmitted at a variable position and the return signal, that is, the reflected portion of the coherent signal is received and coherently detected. The transmitter utilizes a scanning laser having an electron beam that impinges upon a variable reflectance mirror that terminates one end of an optical cavity. An oscillating mode is generated within the resonant cavity when the electron beam locally heats the surface of the variable reflectance mirror to create a pixel that reflects light in a diffracted pattern. The receiver utilizes a stable single mode laser to illuminate a variable reflectance surface. A receiver electron beam generates a plurality of receiver pixels at various positions. The diffracted light from each pixel generates a plurality of variable angle local oscillator beams that are summed with the return signal at a beamsplitter. The output of the beamsplitter is applied to the surface of a detector array.

Abstract: In an optical radar system a coherent signal is transmitted at a variable position and the return signal, that is, the reflected portion of the coherent signal is received and coherently detected. The transmitter utilizes a scanning laser having an electron beam that impinges upon a variable reflectance mirror that terminates one end of an optical cavity. An oscillating mode is generated within the resonant cavity when the electron beam locally heats the surface of the variable reflectance mirror to create a pixel that reflects light in a diffracted pattern. The receiver utilizes a stable single mode laser to illuminate a variable reflectance surface. A receiver electron beam generates a plurality of receiver pixels at various positions. The diffracted light from each pixel generates a plurality of variable angle local oscillator beams that are summed with the return signal at a beamsplitter. The output of the beamsplitter is applied to the surface of a detector array.

Abstract: A method and apparatus for generating a plurality of secondary directional modes within the resonant cavity of a scanning laser oscillator. A first directional mode is generated by directing an electron beam on a variable reflectance end reflector to create a variable position pixel. A pattern of fixed reflectance material is positioned on the surface of the variable reflectance end reflector to generate the secondary directional modes within the resonant cavity. The oscillation threshold for the secondary directional modes is higher than the first directional mode, thereby allowing the first directional mode to have priority over the second directional modes. The second directional modes occupy the regions of the active laser medium of the resonant cavity not occupied by the first directional mode thereby suppressing the gain of the laser medium therein.

Abstract: A circuit for controlling the position of a driven member is disclosed which includes a control circuit for controlling the application of electrical power to a motor and a circuit element operable for generating position error signals corresponding to the position of the load which may in one embodiment constitute a rotor element of the motor. A comparator section is provided for comparing the position error signals with position reference signals and for generating control signals to effect rotation of the load in a desired direction. In one embodiment, the error signal is generated by a feedback loop including a potentiometer having a movable element coupled to the load or motor rotor, wherein the voltage magnitude of the error signal is varied in accordance with the rotational position of the load or rotor element. In a preferred embodiment, the comparator section includes first and second comparators respectively responsive to position deviations of the rotor in first and second rotational directions.

Abstract: Composite protective coatings for protecting carbonaceous substrates from degrading in oxygen containing environments are provided. The composite protective coatings include a first coating layer applied to the surface of the substrate. The first coating layer is a silicon carbide type coating. The second coating layer is applied to the surface of a first coating layer and is a sputter deposited phase stabilized zirconium oxide having a columnar microstructure. Carbonaceous substrates having the composite protective coatings are able to withstand temperatures of about 4100.degree. F. in oxygen containing environments.

Abstract: Stimulated emission at the approximate wave length of 4.5 microns, 2.25 microns and 1.6 microns is obtained from pumping on an excited energy level. The phenomenon of photon avalanching is utilized to create a population inversion within three lower level states that have a substantially equal energy spacing to provide resonance between neighboring ions. This resonance feeds the photon avalanching process when pump having sufficient power in excess of the critical pump power irradiates a LaCl.sub.3 :Pr.sup.+3 crystal at an excited energy level to maintain a population inversion in an optical cavity.

Abstract: A septum (18) is installed at a desired depth within a section of honeycomb core (12) for use in a sound attenuation panels, the septum is sandwiched between two layers (20, 24) of support material having a melting temperature intermediate between the fusing and curing temperatures of the septum material. The honeycomb core (12) is pressed into supporting materials and septum to segment and position the septum (18) therein, after which the resultant assembly is heated sufficiently to allow the septum to fuse and adhere to the honeycomb core. The resultant assembly is then heated sufficiently to melt the support material and allow it to be drained away, leaving the segmented septum (18) in place within the honeycomb core.

Abstract: A propulsion system for vertical take off and landing aircraft includes a forward compressor fan (40) and an aft compressor fan (42) downstream of the forward fan and in series flow communication with the forward fan. The forward and aft fans are positioned in a central duct (26). A gas turbine engine (44) is in series flow with the forward and aft fans for driving the fans. The forward fan, aft fan and turbine engine are interconnected by a common shaft (50). A forward diverter structure (100) is positioned downstream of the forward fan and is movable between a first position for diverting exhaust from the forward fan downwardly relative to the longitudinal axis of the aircraft while simultaneously permitting the introduction of air behind the forward diverter structure but ahead of the aft fan and a second position wherein the exhaust from the forward fan is channeled through the aft fan and turbine.

Abstract: A process for sealing silicon carbide primary coatings of carbonaceous substrates comprising impregnation and curing with tetraethyl orthosilicate, application of a sealant mixture followed by curing, application of a liquid sealant followed by curing, high temperature heat treatment, and repetitive of the application of the materials described above.

Abstract: The specification discloses a method and apparatus for stabilizing images in the reference frame of a forward or down looking infrared receiver moving relative to the scene. An infrared modulator (14) is disposed in the image plane of the receiver for imaging infrared energy from the scene. The modulator (14), normally nonreflecting of infrared energy incident thereon, is capable of having reflective spots written on selected locations thereon to reflect infrared energy incident at those locations. Detectors (24) positioned to detect infrared energy reflected from the modulator provide an output signal representing the radiance values of the sampled scene element. A microprocessor (30) is connected to the detector, responsive to the detected output signal, to detect image motion caused by relative motion between the receiver and the scene from the detected information.

Abstract: A pair of simple phase-sensitive full-wave high-gain demodulator circuits generate an output for both halves of an AC reference cycle. One of the demodulator circuits is utilized as an amplifier to drive, for example, the steering system servo valve in an aircraft steering system and the other demodulator drives a dummy load which has a resistivity approximately equal to the resistivity of the servo valve coils. The output current from both demodulators are compared, for example, by an opto isolator or coupler which generates corrective and/or warning signals in case a system failure occurs. In one embodiment, the sensor output loop is maintained at a predetermined voltage level above ground so that an open circuit in the sensor loop is detected by additional sensing circuits.

Abstract: An image processing system is disclosed wherein information corresponding to a selected geographical region or geometric system is stored and selectively retrieved and processed to reproduce images corresponding to selected portions of the geographical or geometric system. In a preferred embodiment, the information is initially recorded photographically and subsequently stored in a digital recording system. Processing, memory, and control systems are employed for producing video signals to be provided to video display units, for producing simulated real time images corresponding to the selected portion of the geographical or geometric system.

Abstract: An aircraft propulsion system is disclosed having an exhaust nozzle structure having an exhaust deflection structure extending within an exhaust duct to direction exhaust flow along selected flow paths. In its preferred embodiment, the exhaust deflection structure is a variable geometry deflection structure having a distal end portion which is movable, relative to adjacent aircraft structure, within an exhaust duct whereby the exhaust deflection structure is positionable as an extension of an upper, aft wall portion of the exhaust duct. In the preferred embodiment, the exhaust nozzle structure includes a guide structure or nozzle segment, connected to the exhaust deflection structure, which is translatably mounted to adjacent aircraft structure for permitting fore and aft movement of the nozzle segment along the aircraft structure.

Abstract: Disclosed is a sealing arrangement comprising two rings which preferably are complementary right trapezoids in cross-section. One ring is an elastomeric sealing ring. The other ring is a semi-rigid non-elastomeric back-up ring which is more rigid than the sealing ring. The rings are carried in a groove in one mating face of two members with mating faces which are movable with respect to each other. The sealing ring is arranged with the face represented by the shorter base of the trapezoid adjacent the member movable with respect to the member carrying the sealing ring and the back-up ring is arranged with the face thereof represented by the longer base of the trapezoid coplanar with the shorter base of the sealing ring. The elastomeric sealing ring is oriented so that it is nearer the area of higher fluid pressure.

Abstract: A dark field infrared telescope. Energy from an infrared scene is focused by a lens (10) onto a thermoptic modulator (12) comprising an optical structure (16) containing a thin film of vanadium dioxide disposed to form the faceplate of a conventional cathode ray tube. The modulator, normally nonreflecting of infrared energy, may have reflecting spots written at selected coordinates thereon by an electron beam from the cathode ray tube. A reflecting spot written on the modulator optically couples a selected element of the scene imaged on the modulator to an infrared detector (52) maintained at low temperature. A retroreflecting mirror (30), cold spectral filter (46), field lens (47), cold field stop (48) and cold pupil stop (50) are provided ahead of the detector to produce a low background flux cavity with the detector at one end and the retroreflecting mirror at the other. In its unswitched state, the modulator is nonreflecting and the scene image is not coupled to the detector.

Abstract: A solar power satellite (30) includes a truss structure (32) having a plurality of independently controlled solar power modules (34) mounted to one face of the truss structure. The solar power satellite is constructed in orbit by first forming and then assemblying component beam members (50, 52) to the truss structure. The solar power modules (34) are constructed on a fabrication and assembly station (36) movably attached to the truss structure and are then attached to the truss structure. The solar power modules (34) include a primary reflector (200) having a substantially parabolic curvature in cross section. A collector-radiator (202) is mounted on the primary axis of the primary reflector. The cross-sectional configuration of the collector-radiator (202) approximates a flattened inverted S-shape whereon the radius of curvature decreases as the curve approaches both its center and its end furthermost from the primary reflector (200).

Abstract: A metal laminate possessing high strength characteristics as well as good ductility and malleability, comprising one or more layers of a superplastic material metallurgically bonded to one or more layers of a non-super plastic material; and the method of preparing the laminate to induce plastic or super plastic characteristics to the nonsuper plastic material.

Abstract: Disclosed is a sealing arrangement comprising two rings which are complementary right trapezoids in cross-section. One ring is an elastomeric sealing ring. The other ring is a semi-rigid non-elastomeric back-up ring which is more rigid than the sealing ring. The rings are carried in a groove in one mating face of two members with mating faces which are movable with respect to each other. The sealing ring is arranged with the face represented by the shorter base of the trapezoid adjacent the member movable with respect to the member carrying the sealing ring and the back-up ring is arranged with the face thereof represented by the longer base of the trapezoid coplanar with the shorter base of the sealing ring. The elastomeric sealing ring is oriented so that it is nearer the area of higher fluid pressure.

Abstract: A loading arm utilizing a counterbalancing mechanism in which half sheaves are utilized to provide one interconnection between the counterbalance and the outboard arm and a member is pivotally connected to both the outboard arm and the counterbalance to provide the other interconnection between the counterbalance and outboard arm to provide for full retracted storage of the arm. Preferably, rods provide the majority of the interconnection between the outboard arm and the counterweight.

Abstract: Disclosed is apparatus for forming and directionally positioning a neutron beam. The apparatus includes an enclosed housing rotatable about a first axis with a neutron source axially positionable on the axis of rotation of the enclosed housing but rotationally fixed with respect to the housing. The rotatable housing is carried by a vertically positionable arm carried on a mobile transport. A collimator is supported by the rotatable housing and projects into the housing to orientationally position its inlet window at an adjustably fixed axial and radial spacing from the neutron source so that rotation of the enclosed housing causes the inlet window to rotate about a circle which is a fixed axial distance from the neutron source and has the axis of rotation of the housing as its center.