Abstract: A dual structure aerospace vehicle 10 having an aeroshell structure 11 and an internally disposed separable and reusable integral tank/thrust structure 13 is disclosed. Tank/thrust structure 13 is insulated for cryogenic fuels and the cavity 24 within aeroshell 11 is insulated from the tank/thrust structure (FIG. 2). An internal support ring 26 within cavity 24 serves as attachment for lugs 30 on tank/thrust structure 13 via double hinges 50 (FIGS. 3 and 4). The aft end of tank/thrust structure 13 is provided with rocket engines and exit nozzles 33, 34, 35 with trunnion support 37 supporting the tank/thrust structure within aeroshell 11.

Abstract: The invention relates to a tetrahedral beam that can be compactly stowed, sequentially deployed, and widely manipulated to provide a structurally sound yet highly maneuverable truss structure. The present beam is comprised of a plurality of repeating units comprised of tandem tetrahedra sharing common sides. Tetrahedra are comprised of fixed length battens 12 joined by joint 14 into equilateral triangles called batten frames. Apexes of adjacent triangles are interconnected by longerons 16 having mid-point folding hinges 20. Joints 14 are comprised of gussets 24,34 pivotably connected by links 25. Joints 14 permit two independent degrees of rotational freedom between joined adjacent batten frames, and provide a stable structure throughout all stages of beam deployment, from packaged configuration to complete deployment. The longerons and joints can be actuated in any sequence, independently of one another. The present beam is well suited to remote actuation.

Abstract: An optical video signal processor which produces a two-dimensional cross-correlation in real time of images received by a stereo camera system. The optical image of each camera (12, 14) is projected on respective liquid crystal light valves (28, 48). The images on the liquid crystal valves (28, 48) modulate light produced by an extended light source (32). This modulated light output becomes the two-dimensional cross-correlation when focused onto a video detector (42) and is a function of the range of a target (1) with respect to the stereo camera (10). Alternate embodiments utilize the two-dimensional cross-correlation to determine target movement and target identification.

Abstract: A thermal probe (10) for averaging temperature fluctuations over a prolonged period is formed with a temperature sensor (22) embedded inside a solid object (12) of a thermally conducting material. The solid object is held in a position equidistantly spaced apart from the interior surfaces of a closed housing (16) by a mount (14) made of a thermally insulating material. The housing is sealed to trap a vacuum or mass of air inside and thereby prevent transfer of heat directly between the environment outside of the housing and the solid object. Electrical leads (24) couple the temperature sensor with a connector (26) on the outside of the housing. Other solid objects of different sizes and materials may be substituted for the cylindrically-shaped object to vary the time constant of the probe.

Abstract: An ejection apparatus (19) for spinning and propelling objects (17) for ejection from a spacecraft (11) at a desired velocity and rotational speed. The apparatus includes a launch cradle (23) on which the space object (17) to be ejected rests. The cradle (23) is rotatably supported by a central hub (37) secured to upper end of pneumatic cylinder piston shaft (25). Release mechanisms (29) consisting of a retractable pin (75) and locking lug (72) is utilized to hold the cradle and object to be ejected. The release mechanism (29) has a fixed barrier member (76) which holds the retractable pin (75) in engagement with the locking lug (72) until release by upward movement of the launch cradle (23) beyond the barrier height.

Abstract: A mechanical actuator can be constructed by employing a plurality of memory metal actuator elements in parallel to control the amount of actuating force. In order to facilitate direct control by digital control signals provided by a computer or the like, the actuating elements may vary in stiffness according to a binary relationship. The cooling or reset time of the actuator elements can be reduced by employing Peltier junction cooling assemblies in the actuator.

Abstract: Amorphous metals are produced by forming a molten droplet (115) of metal from source (126) and deploying the droplet into a focused acoustical levitating field or by dropping the unit through spheroidizing zone (116) slow quenching zone (118) and fast quenching zone (120) in which the droplet is rapidly cooled by in the standing acoustic wave field produced between half-cylindrical acoustic driver (168) and focal reflector (166) or curved driver (38) and reflector (50). The cooling rate can be further augmented by first cryogenic liquid collar (160) and second cryogenic liquid jacket (170) surrounding the drop tower (112). The sphere (117) is quenched to an amorphous solid which can survive impact in the unit collector (124) or is retrieved by vacuum chuck (20).

Abstract: A process of endcapping a polyimide system with an endcapping agent in order to achieve a controlled decrease in molecular weight and melt viscosity along with predictable fracture resistance of the molded products is disclosed. The uncapped system is formed by combining an equimolar ratio of 4,4'-bis(3,4-dicarboxyphenoxy) diphenylsulfide dianhydride (BDSDA) and 1,3-bis(aminophenoxy)benzene (APB) dissolved in bis(2-methoxyethyl)ether. The endcapped system is formed by dissolving APB in bis-(2-methoxyethyl)ether, adding the endcapping agent, and then adding the BDSDA. By varying the amount of endcapping from 0 to 4%, molecular weight is decreased from 13,900 to 8660. At a processing temperature of 250.degree. C., there is a linear relationship between molecular weight and viscosity, with the viscosity decreasing by two orders of magnitude as the molecular weight decreased from 13,900 to 8660. A greater drop in viscosity is noted at higher temperatures.

Abstract: A high frequency oscillator circuit is provided using a low cost junction type field effect transistor (T.sub.1) with a tuned circuit connected to its gate. The frequency of operation is determined by the tuned circuit and the capacitance reflected from the source to the gate. The transistor is matched to the frequency of operation so that this frequency falls within the roll-off portion of the transistor's transconductance verses frequency curve, preferably somewhat above the 3 db point in frequency. Phase shifting necessary to sustain oscillation occurs due to the operation of the transistor in the roll-off portion of the curve and the addition of a phase shifting network (R.sub.1, C.sub.1) at the source. The resulting oscillator is small, stable, linear and inexpensive.

Abstract: A novel air bearing structure prevents destructive bending moments within the top foil. Welds are eliminated by mounting the top bearing foil in the bearing cartridge sleeve without using a spacer block.Tabs or pins at the end of the top bearing foil are restrained by slots or stops formed in the cartridge sleeve. These structural members are free to move in a direction normal to the shaft while being restrained from movement in the direction of shaft rotation.

Abstract: A high common mode rejection differential amplifier wherein two serially arranged Darlington amplifier stages (28, 44) are employed and any common mode voltage is divided between them by a resistance network (53). The input to the first Darlington amplifier stage (28) is coupled to a signal input resistor (8) via an amplifier (16) which isolates the input and presents a high impedance across this resistor. The output of the second Darlington stage (44) is transposed in scale via an amplifier stage (66) which has in its input a biasing circuit which effects a finite biasing of the two Darlington amplifier stages (28, 44).

Abstract: By using two SAR antennas spaced a known distance, B, and oriented at substantially the same look angle to illuminate the same target area, pixel data from the two antennas may be compared in phase to determine a difference .DELTA..phi. from which a slant angle .theta. is determined for each pixel point from an equation .DELTA..phi.=(2.pi.B/.lambda.)sin(.theta.-.alpha.), where .lambda. is the radar wavelength and .alpha. is the roll angle of the aircraft. The height, h, of each pixel point from the aircraft is determined from the equation h=R cos .theta., and from the known altitude, a, of the aircraft above sea level, the altitude (elevation), a', of each point is determined from the difference a-h. This elevation data may be displayed with the SAR image by, for example, quantizing the elevation at increments of 100 feet starting at sea level, and color coding pixels of the same quantized elevation.

Abstract: An energy recovery system is provided for an aircraft gas turbine engine of the type in which some of the pneumatic energy developed by the engine is made available to support systems such as an environmental control system. In one such energy recovery system, some of the pneumatic energy made available to but not utilized by the support system is utilized to heat the engine fuel immediately prior to the consumption of the fuel by the engine. Some of the recovered energy may also be utilized to heat the fuel in the fuel tanks. Provision is made for multi-engine applications wherein energy recovered from one engine may be utilized by another one of the engines or systems associated therewith.

Abstract: A method and apparatus for inspecting the surface of a bearing ball is disclosed which includes a base (A) having a high friction non-abrasive base scanning surface (12). A holding device (B) includes a cone-shaped cup recess (14) in which a ball element (18) is received. Air is introduced through a passage (26) to relieve friction between the wall (16) of the recess and the ball element and facilitate rolling of the ball over the high friction base surface. The holding device is moved over the base scanning surface in a predetermined pattern (50) such that the entire surface of the ball element is inspected by an eddy current probe (C) which detects any surface defects.

Abstract: A frequency control system is provided which makes an initial correction of the frequency (f.sub.CLK) of its own timing circuit (50, 52, 54, 56) after comparison against a frequency (f.sub.REF) of known accuracy and then sequentially checks and corrects the frequencies of several voltage (13a . . . 13e) controlled local oscillator circuits (12a . . . 12e). The timing circuit initiates the machine cycles of a central processing unit (30) which, over a sampling interval having a duration of a fixed number of machine cycles, applies a frequency index (FI) to an input register (22) in a modulo-sum frequency divider stage (20) and enables a multiplexer (16) to clock an accumulator register (26) in the divider stage (20) with a cyclical signal derived from the oscillator circuit being checked.

Abstract: 4-Aminophenoxy cyclotriphosphazenes are reacted with maleic anhydride to produce maleamic acids which are converted to the maleimides. The maleimides are polymerized. By selection of starting materials (e.g. hexakis amino or trisaminophenoxy-trisphenoxy-cyclotriphosphazenes), selection of molar proportions of reactants, use of mixtures of anhydrides and use of dianhydrides as bridging groups a variety of maleimides and polymers are produced. The polymers have high limiting oxygen indices, high char yields and other useful heat and fire resistant properties making them useful as, for example, impregnants of fabrics.

Abstract: Cured polyfunctional epoxy resins including tris(hydroxyphenyl)methane triglycidyl ether are toughened by addition of polybrominated polymeric additives having an EE below 1500 to the pre-cure composition. Carboxy-terminated butadiene-acrylonitrile rubber is optionally present in the precure mixture as such or as a pre-formed copolymer with other reactants. Reinforced composites, particularly carbon-reinforced composites, of these resins are disclosed and shown to have improved toughness.

Abstract: A method and apparatus for testing the tensile strength and bonding strength of sprayed-on foam insulation (12) attached to metal cryogenic fuel tanks (14). A circular cutter is used to cut the insulation (12) down to the surface of the metal tank to form plugs of the insulation (12) for testing "in situ" on the tank (14). The apparatus comprises an electro-mechanical pulling device (32) powered by a belt battery pack (34). The pulling device (32) comprises a motor (60) driving a mechanical pulling structure comprising a horizontal shaft (64) connected to two bell cranks (68) which are connected to a central member (74). When the lower end of member (74) is attached to fitting (20), which in turn is bonded to plug (10) (see FIG. 2), a pulling force is exerted on plug (10) sufficient to rupture it. The force necessary to rupture the plug (10) or pull it loose is displayed as a digital read-out (51) on screen (50).

Abstract: The voltage rating of a bipolar transistor may be greatly extended while at the same time reducing its switching time by operating it in conjunction with FETs in a hybrid circuit. One FET is used to drive the bipolar transistor while the other FET is connected in series with the transistor and an inductive load. Both FETs are turned on or off by a single drive signal of load power, the second FET upon ceasing conduction, rendering one power electrode of the bipolar transistor open. Means provided to dissipate currents which flow after the bipolar transistor is rendered nonconducting.

Abstract: A telescoping manipulator arm and pivotable finger assembly are disclosed. The telescoping arm assembly (A) includes a generally T-shaped arm (18) having three outwardly extending fingers (18a, 18b, 18c) guided on the grooved roller guides (12, 14, 16) to compensate for environmental variations. The pivotable finger assembly (D) includes four pivoting fingers (50, 66, 70, 74). Arcuate teeth (52, 58, 60, 62) are formed on the ends of the fingers. A rack (54) having teeth on four sides meshes with each one of the fingers. One surface of the rack (54) includes teeth (56) along its entire surface which mesh with teeth (52) of the finger (50). The teeth (56) at the remote end of the rack (54) engage teeth (80) of a gear wheel (81). The wheel (81) includes a worm (82) which meshes with a worm drive shaft of the drive motor (86) providing a ninety degree self-locking drive (E) for locking the fingers in a desired position.