Abstract: A piezoelectric motor actuated amplifier mechanism that utilizes a pair of saggital linkages having one relatively fixed saggital midpoint and joined at their end points to obtain a doubled amplification factor pull stroke output from one relatively movable saggital midpoint. Thermal compensators are employed between the piezoelectric actuator and the saggital linkages to stabilize the amplifier throughout a wide range of temperatures.

Abstract: A method for controlling transition from thruster control to momentum wheel control to minimize nutation angle and transition time in a three-axis stabilized spacecraft employing an internal body fixed-momentum wheel as an attitude stabilizer. The method employs direct, substantially real-time measurement of momentum components and angular rates and generates paired roll thrust impluses and paired yaw thrust impulses in synchronization with the nutation period of the spacecraft to drive the spacecraft to a state of substantially zero nutation. The controller employs a deadbeat principle in a closed-loop real-time feedback system. In a preferred embodiment, the impulsive thruster firing commands in roll and yaw are simultaneous, spaced one-half nutation period apart in time with the effect that the target momentum is achieved in one to three pairs of impulse firings.

Abstract: A time delay shifter imparts a constant time delay to an electromagnetic signal, preferably a signal at a microwave frequency, over a band of frequencies. The phase shift imparted to the signal is a linear function of frequency. The shifter comprises a finite number of delay units (1) each having four single-pole single-throw switches (11-14). Closure of the first and third switches (11, 13) causes the signal to traverse a first path (2) containing a preselected length of transmission line that imparts a fixed time delay to the signal. Closure of the second and fourth switches (12,14) causes the signal to traverse a minimum-delay path (3) which is shorter than the delay path (2). The paths (2,3) are fabricated of coplanar waveguide. Each switch (11-14) is resonated by an inductor (21-24) for purposes of increasing isolation. An attenuator (70) is inserted in each minimum-delay path (3).

Abstract: A telescope body is disclosed. The telescope body generally includes a primary structure for holding a mirror, a secondary structure for holding a means for receiving a reflection from the mirror, and a mounting section connecting the primary and secondary structure. The primary and secondary structures include four-bar linkages which have linkage action planes intersecting at the focal point of the mirror. Apparatus for preventing the secondary structure from intruding in a raypath of light to the means for receiving a reflection is also disclosed.

Abstract: Consolidation of active and passive detectors (26, 28, 34) on a single coldfinger (20) in a dewar (10) is made possible by interposing between the detectors (26, 28, 34) an electromagnetic interference shield (64, 68) which acts as a waveguide filter blocking any interfering frequencies. The waveguide is formed by a pair of spaced interleaved shields (64, 68), one of which (64) is associated with the dewar envelope and is externally grounded, and the other of which is associated with the coldfinger (20). Photons which penetrate through the waveguide (64, 68) are deflected to the outside of the dewar (10) by a flanged narcissus shield (40) surrounding the passive detector (34).

Abstract: A novel packaging system for VLSI circuits allows low-cost construction and maintenance of complex high density high-performance devices with low power requirements. The devices can be individually created by software means from a small selection of standardizable IC chips by disposing a plurality of chips in leadless chip carriers in a mosaic on a substrate, and configuring them by software to selectively communicate with other chips of the mosaic or even to individually change their operating function. The immediate juxtaposition of the chip carriers in the mosaic eliminates transmission line data skew, and also allows considerable savings in chip space and power requirements by dispensing with interconnection drivers, receivers and bonding pads.

Abstract: A novel packaging system for VLSI circuits allows low-cost construction and maintenance of complex high density high-performance devices with low power requirements. The devices can be individually created by software means from a small selection of standardizable IC chips by disposing a plurality of chips in leadless chip carriers in a mosaic on a substrate, and configuring them by software to selectively communicate with other chips of the mosaic or even to individually change their operating function. The immediate juxtaposition of the chip carriers in the mosaic eliminates transmission line data skew, and also allows considerable savings in chip space and power requirements by dispensing with interconnection drivers, receivers and bonding pads.

Abstract: The manufacture of monolithic HgCdTe detectors and Si circuitry in an IR focal plane array is achieved by forming a protective layer of SiO.sub.2 or SiN.sub.x on a silicon wafer containing silicon circuits, etching steep-wall recesses into the wafer, selectively depositing epitaxial single-crystal layers of GaAs, CdTe, and HgCdTe in the recesses fabricating HgCdTe IR arrays, and depositing appropriate insulating and conductive interconnection patterns to interconnect the Si devices with one another and the HgCdTe devices with the Si devices. Little or no GaAs, CdTe, and HgCdTe grows on the SiO.sub.2 or SiN.sub.x outside the recesses. Since material grown outside the recess is polycrystalline, it is easily chemomechanically removed.

Abstract: A microwave-frequency microstrip antenna (10) simultaneously usable for both transmitting and receiving microwave-frequency signals that have dual orthogonally polarized components. The components may be either linearly or circularly polarized. A radiating patch (26) is mounted on a first dielectric (12). A ground plane (20) abuts the first dielectric (12) and has two elongated coupling apertures (32,31) at right angles to each other. A second dielectric (22) abuts the ground plane (20) and has embedded thereon two substantially identical conductive planar feed networks (52,51) that are disposed at right angles to each other. At least one additional optional dielectric layer (16,18) having a conductive patch (36,34) may be interposed between the first dielectric (12) and the ground plane (20) for purposes of broadening the bandwidth of the antenna (10). A meanderline polarizer (45) or a 3 dB 90.degree. hybrid coupler (40) may be used for converting from linear polarization to circular polarization.

Abstract: Apparatus for gaging the amount of liquid propellant remaining in a spacecraft (38) tank (1). The tank (1) comprises several preferably V-shaped channels 2A, 2B, 2C, 2D, hereinafter collectively referred to as "2" which communicate liquid propellant from regions within the tank (1) to an outlet port (8) that expels liquid propellant but not pressurant gas. A liquid/bubble chamber assembly (9) couples the channels (2) with the outlet port (8). The channels (2) comprise relatively open portions (11) and relatively closed portions (10). A first ultrasonic transducer (31) is positioned along the outside of the tank (1) and detects a condition of near propellant depletion by measuring the amount of liquid retained in the relatively open portions (11) of the channels (2). The liquid/bubble chamber assembly (9) comprises a liquid trap (27) and a bubble trap (28).

Abstract: An inexpensive, reliable analog ramped-voltage timing device (34, 36, 38, 40, 44) can be used in a laser echo ranging device capable of resolution in the decimeter range by using a very steep ramp (42), and a flash A/D converter (50) to instantaneouly sample the ramped voltage upon receipt of the laser echo.

Abstract: A method and apparatus for combining encoding and modulation creates signal sets from available amplitude and phase modulations by indexing ordered subspaces. The subspaces need not be limited to the class of subspaces known as binary subspaces. The resultant signal sets, for a preselected power and bandwidth, are widely separated and unlikely to be confused by the effects of channel noise. Such signals can be in either finite block or convolutional form, depending on the natural format of the desired transmission. Further according to the invention are basic apparatus for encoding and modulating as well as demodulating and decoding a signal in accordance with the invention. Specifically, a method is provided for decoding the incorporates a specific type of decoding/demodulation techniques which develops accurate estimates of the information from the received signal in a computationally efficient manner and which permits high speed operation using softdecision decoders.

Abstract: A multi-spectral reticle projector coaxially projects two separate reticles at different wavelengths through a single aperture by using a lens system including a dichroic lens disposed coaxially between the two reticles. The visible light is reflected by the mirror and passes through the lens system twice, while the infrared light passes through the mirror and passes through the lens system once. At the output of the lens system, the two reticle images are superimposed, collinated and coaxial.

Abstract: An ammunition round has a plastic molded driving band on a projectile. The driving band is mechanically attached to the projectile by opposing curved hooks bent toward one another and defining a restraining area therebetween. The seating area for the driving band has a plurality of pairs of such hooks circumferentially and longitudinally displaced from one another.

Abstract: A Schottky barrier photodiode for detecting infrared radiation uses implantation of metal ions to form a metal silicide. An annular N+ type silicon guard ring is formed in a p-type silicon substrate. Metal ions are implanted into the exposed surface area of the silicon substrate surrounded by the silicon guard ring. The resulting structure is annealed to form a silicide of the implanted metal. A portion of the silicon substrate encircled by the silicon guard ring and above the metal silicide is removed. A thin oxide passivating layer is formed above the metal silicide.

Abstract: Apparatus for dividing and combining electromagnetic energy, particularly at microwave frequencies. An input port (4) is positioned generally equidistant from each of n output ports (5,6;31,32,33 . . . ), where n is a finite integer greater than 1. n quarter-wavelength impedance transforming conductors (20;41,42,43 . . . ) couple the input port (4) to the n output ports (5,6;31,32,33 . . . ), respectively. Positioned between each pair of adjacent output ports (5,6;31,32,33) is an isolation resistor (7). A pair of half-wavelength unity impedance transformers (21) couples each isolation resistor (7) to its two associated output ports (5,6;31,32,33 . . . ), respectively. The invention allows greater geometrical freedom than prior art splitters, and offers a lower loss for a given frequency.

Abstract: A variable conductance thermal insulation blanket regulates the temperature of a component (20) on the surface (32) of a spacecraft. The blanket comprises a sealed container (2) and a pressurized gas tank (10). When gas is introduced from the tank (10) into the sealed container (20), heat is conducted away from the component (20) into outer space via conduction through the gas molecules. Thus, component (20) is cooled. When gas is evacuated from within sealed container (2) and there is a vacuum there-within, heat conduction is thwarted, and the primary means of heat escape from component (20) is via radiation. However, radiation is also thwarted by means of a set of stacked radiation sheilds (24) having low emissivity but high thermal conductivity.

Abstract: An attitude control system for a three-axis controlled spacecraft (1) in which the location of thrusters causes significant cross-coupling torques. A thruster command conditioning electronics module (TCCEM) (3) is positioned between the conventional roll, pitch, and yaw loop controllers (41-43) and the thrusters (61-63). The TCCEM (3) converts spacecraft-axis-based torque requirement signals (TDX, TDY, TDZ) emanating from the loop controllers (41-43) into scalar quantities (UL, UM, UN) that are input to thruster modulators (51-53) that turn on one or more thrusters of the thruster pairs (L,M,N). The TCCEM (3) causes the spacecraft (1) attitude to be adjusted as commanded by the torque requirement signals (TDX, TDY TDZ) despite the presence of the cross-coupling. Two embodiments are illustrated: a working embodiment in which cross-coupling torques are produced about two axes (Y,Z), and a more general embodiment in which cross-coupling torques are present about all three axes (X,Y,Z).

Abstract: A wideband, aperture-coupled microstrip antenna comprising a multilayer structure and including a feed layer, a ground plane including an aperture therethrough, a plurality of tuning layers formed of dielectric material, at least one of the tuning layers including therein a tuning element in the form of an electrically-conductive material, herein called a tuning patch, and final radiating layer including a radiating patch. The multiple tuning layers serve to extend the operational bandwidth of the antenna as compared to other microstrip antennas. Aperture coupling allows realization of the antenna using integrated circuit fabication techniques without the shortcoming of direct physical connections between the feedline and the radiator, and thus providing simple, yet reliable coupling between the feedline and the antenna.

Abstract: An optical scanning apparatus embodied in a gyroscopic missile seeker to provide a rosette scan pattern of the field of view. A single driving motor is employed with a traction drive assembly to produce the necessary counter-rotation of scanned elements and thereby effect the rosette scan pattern.