Abstract: An antenna-oriented reflecting material using triaxial woven fabric is usable for frequency bands as high as 20-60 GHz. A reflecting material 1 usable for the high frequency bands is manufactured without spoiling advantages of triaxial woven fabric 2 by controlling mainly a construction n, a volume resistivity .rho. and a mass per unit length .eta. of the triaxial woven fabric. Particularly the setting of each parameter is determined by a composite model reflection ratio .GAMMA. obtained from a sum of a first reflection ratio .GAMMA.'s based on a surface resistance of the triaxial woven fabric and a second reflection ratio .GAMMA.p based on opening, holes of the triaxial woven fabric. It is preferable that a construction be 5-28 yards/in a mass per unit length .eta. be 10-460 tex g/1000 m, and a volume resistivity .rho. be 0.7 to 2.0.times.10.sup.-3 .OMEGA..multidot.cm.

Abstract: A motion control apparatus is provided for controlling oscillations of an appendage 10 coupled to a spacecraft 12. A plurality of guidelines 20 extend between remote portions 22 of the appendage 10 and the appendage base 14. A plurality of motion control elements 28 are interposed between the appendage base 14 and the spacecraft 12 and/or along the guidelines 20 between the appendage base 14 and the remote portions 22 of the appendage 10 or both. The motion control elements 28 include visco-elastic fluid, electro-rheological fluid, magnetic-rheological fluid, or a piezo-electric stack so that a motion control property of the motion control elements 28 may be varied according to the magnitude of an electric or magnetic field source 30 coupled thereto.

Abstract: An unfurlable reflector antenna system having one or more unfurlable arms that are each shaped in the form of a parabolic right cylinder when it is unfurled. Each arm comprises an RF reflecting membrane or a thin shell as the reflector structure. Each arm is coupled by way of a line feed to a receiver. The system is specifically designed for use on a spacecraft. Each arm may be stowed by flattening the parabolic membrane or shell, and then rolling up the arm, which is accomplished without stretching. The sparse reflector antenna array system is thus stowable in a compact configuration, yet easily unfurls to provide a very large diameter lightweight reflector.

Abstract: A method and system for deploying a multi-reflector antenna system (10). The antenna system (10) includes an antenna structure (12) mounted to a satellite (14), where an antenna feed array (16) is mounted to the antenna structure (12). A single articulated antenna arm assembly (26) is mounted to the antenna structure (12) by a first spring loaded hinge (28). The arm assembly (26) includes a first arm (30) on which is mounted a first reflector (38), and a second arm (32) on which is mounted a second reflector (40). The first and second arms (30, 32) are connected to each other by a second spring loaded hinge (34) such that the reflectors (38, 40) directly oppose each other and are substantially parallel when the arm assembly (26) is in the stowed position. A plurality of launch locks (44, 46, 50, 54) hold the arm assembly (26) in the stowed position against the bias of the hinges (28, 34) prior to deployment.

Abstract: A semiconductor array assembly comprises an antenna array portion including a plurality of photonically-activatable semiconductor elements. The array assembly may also include a solar energy collection array portion having a plurality of photovoltaic cells. The two arrays may be supportably positioned on opposing sides of a common support structure (e.g. a dielectric substrate). An activation arrangement is provided to transmit photonic energy from an external source, such as solar radiation from the sun, received on a back side of the assembly to photonically-activatable elements to increase their electrical conductivity and thereby activate them for transmission and/or reception of electromagnetic signals. The activation arrangement may also feed photonic energy from an internal photonic energy source, such as laser diodes, through optical fibers to activate the photonically-activatable elements.

Abstract: An antenna reflector comprising a single membrane antenna reflector surface and means for supporting said antenna reflector surface are disclosed wherein a shape of said antenna reflector is reconfigured to assume a stowed position. The shape of the stowed reflector allowing a large, single piece antenna reflector to be stowed efficiently inside a minimum payload area of the space vehicle. The method and apparatus of this invention ensure that both the deployed and stowed surfaces of the membrane antenna reflector are isometric, or length preserving, mappings of one another. The circumferential dimension of the antenna reflector is decreased having the effect of rolling up the paraboloid so that its surface is similar to a cone. Additionally, the method and apparatus are employed such that when the antenna reflector surface is deployed the antenna reflector membrane unrolls without stretching.

Abstract: An improved dual gridded reflector antenna configuration which allows cross-polarization radiation to be scanned in any given direction. The dual-gridded reflector assembly includes a front parabolic reflector illuminated by a first source, and a second parabolic reflector illuminated by a second source. The second reflector is positioned adjacent to and behind the front reflector such that the center points of the reflectors align to define a center axis. Additionally, the first and second sources are positioned at different offsets with respect to the reflectors and have a respective rotated offset angle with respect to the center axis such that the sources define an antenna feed separation. By modifying the offsets and the rotated offset angles, the feed separation can be designed to have an inclination with respect to the north-south or east-west feed separation direction.

Abstract: A friction retaining device for holding and releasing reflector panels of a satellite. The retaining devices having a friction bushing mounted thereon to prevent the reflectors from becoming disengaged from the clamp. The retaining device has a pair of opposing arms having upper ends that communicate with bumpers on the reflectors and lower portions that communicate with a release mechanism. Upon actuation of a pyrotechnic device, the reflectors are deployed. At the same time, the release mechanism disengages the lower portions of the opposing arms allowing them to remove the bumpers from the reflectors.

Abstract: The integration of traveling wave tube amplifiers and multiplexers onto passive transmit array antenna panels deployed out board of a spacecraft bus to simultaneously provide a spacecraft transponder that permits antenna pattern flexibility in orbit, high DC to RF power conversion efficiency, facilitates higher spacecraft power and provides a spacecraft with deployed payload panel architecture having multiple independent beams that can be electronically reconfigured on the ground or in orbit.

Abstract: An apparatus for deploying an umbrella-type structure such as an antenna reflector is provided. The umbrella-type structure includes a plurality of rib members movable from a stowed configuration to a deployed configuration. The deployment apparatus comprises a movable deployment tube and a hub pivotally attached to the plurality of rib members and slidably attached to the deployment tube. The hub is adapted to move along the deployment tube. The deployment apparatus further includes a plurality of rib deployment straps connecting the deployment tube to the rib members and a mechanism for moving the deployment tube in order to tension the rib deployment straps which in turn pull the rib members into the deployed configuration. The apparatus includes structural members made of composite materials, having a low (near zero) coefficient of thermal expansion, low density, and high strength.

Abstract: A Multi-Band Concentric Helical Antenna (20) operating in a novel conical mode, useful for general and satellite communications is disclosed. A higher frequency helix (24) is placed concentrically inside a lower frequency one (22). In one embodiment, each helix has four helical elements (22a-d, 24a-d). The outer helix is fed at a first frequency (f.sub.1) and the inner helix (24) is fed at a second frequency (f.sub.2). The second frequency (f.sub.2) may be greater than twice the first frequency (f.sub.1). Both helices (22, 24) have the same polarization. The pitch (P.sub.1, P.sub.2), diameter (D.sub.1, D.sub.2), and length (AL.sub.1, AL.sub.2) of the helices are chosen so that said antenna (20) radiates with approximately equal flux at all points in a far-field plane. Alternatively, two inner helices (24, 25) are placed concentrically within an outer helix (22).

Abstract: A universal communication system enables dedicated and independent communications capability to NSTS payload elements and ground based communications networks. The system may either utilize existing communications satellites as an intermediate network to provide continuous communications with payload elements, regardless of orientation or configuration of the NSTS Orbiter, or may communicate directly with ground stations via down link capability. In addition, the universal communications system can provide supplemental and independent communications capacity to the NSTS Orbiter's primary communication system.

Abstract: An antenna having dual reflectors connected by a moving mechanism for moving the reflectors between stowed and deployed positions. In the stowed position the reflectors overlap and are positioned close to each other. In the deployed position the reflectors are spaced apart.

Abstract: An efficient multi-beam antenna system for use with a high capacity communications satellite or spacecraft that maximizes frequency re-use of the allocated frequency spectrum. The antenna system has first and second offset reflectors disposed adjacent first and second sides of the spacecraft. A first plurality of the feed horns feed the first reflector, and a second plurality of the feed horns feed the second reflector. The feed horns and offset reflectors cooperate to produce a predetermined number of beams. Even numbered beams use a set of frequencies and polarizations that are orthogonal to a set of frequencies and polarizations used by odd numbered beams. The antenna beams are contiguous in one dimension.

Abstract: An array antenna (12atf) particularly useful for a spacecraft includes a plurality of antenna elements (310). Each of the elements includes a conductive hexagonal cup (408) having sides (410a, 410b, 410c, . . .) which are thirteen twentieths of a wavelength long at the center frequency, and have a height above the bottom (412) which is a little more than one-third wavelength. A crossed dipole (420) includes two dipoles (420V, 420H), the first (421, 422) having elements approximately one quarter wavelength long, and the second (420H) having elements (423, 424) about three twentieths of a wavelength long. The plane of the crossed dipole is about one quarter wavelength above the bottom of the cup. A first director ring (512) has a diameter of about one quarter wavelength, and is spaced about nine tenths of a wavelength above the bottom. A second director ring (514) has a like diameter, and is spaced about seven tenths of a wavelength above the bottom of the cup.

Abstract: A spacecraft of a set of spacecraft has an antenna support frame defining square apertures, which are the same size in all spacecraft of the set of spacecraft. The set also includes a plurality of radiating tiles for various operating frequencies. The tiles all have the same dimensions, so that any combination of tiles may be mounted in the apertures of the frames of any spacecraft to form antenna arrays of various sizes, depending upon the customer's requirements. Each tile includes plural beamformers and power amplifiers, and remotely controllable phase shifters and level controls, for ready reconfiguration of the antennas while the spacecraft is in operation. The preferred dimension of each radiating tile is a one-foot square.

Abstract: A steerable feeder link antenna is formed of a steerable reflector and a stationary feed horn assembly. A novel feed horn assembly allows dual mode transmit and receive functions for circularly polarized microwaves. The feed horn assembly includes a four arm turnstile junction coupled to a feed horn through the feed horn's side wall to couple transmit frequencies and an axially coupled transmission line for the receive frequencies. Each turnstile junction arm incorporates chokes for the receive frequencies. The transmission line's cut off frequency is above the transmit frequency to prevent transmit signals from interfering with receive signal receivers.

Abstract: A universal communication system enables dedicated and independent communications capability to NSTS payload elements and ground based communications networks. The system may either utilize existing communications satellites as an intermediate network to provide continuous communications with payload elements, regardless of orientation or configuration of the NSTS Orbiter, or may communicate directly with ground stations via down link capability. In addition, the universal communications system can provide supplemental and independent communications capacity to the NSTS Orbiter's primary communication system.

Abstract: A data transmitting/receiving satellite terminal for transmitting to and receiving from a geosynchronous satellite employs an antenna having nulls in its antenna receiving pattern at a first frequency corresponding to satellites spaced at regular intervals from the satellite. In addition, a phase and amplitude compensation network adjusts a phase and amplitude of the transmitted signal to compensate for transmitting at a different frequency than for which the antenna is optimally designed. The antenna includes a main parabolic reflector, and two side parabolic reflectors offset from a plane parallel to the main parabolic reflector. Each of the reflectors uses a dual frequency feed horn to couple energy to and from the reflector to a dipole exciter to which the receiving electronics is coupled. The above terminal is particularly useful in C-Band applications.

Abstract: A geostationary satellite includes a three-axis stabilized body including an onboard computer and at least one solar generator wing extending in a longitudinal direction from the body and coupled to the body by a drive system controlled by the onboard computer and adapted to rotate the wing at least about its longitudinal axis. The satellite further comprises a static radar surveillance device including at least one antenna formed of elementary plane radiating patches and adapted to scan at least part of the space surrounding the satellite body.

Abstract: The deployable helical antenna of the present invention and helical antenna deployment system includes a helical antenna having a plurality of helical filars and at least two guide plates positioned with respect to the helical filars. Each of the guide plates is provided with a plurality of guide elements operably attached to a corresponding helical filar. The novel helical antenna of the present invention can be collapsed into a stowed position such that each of the helical filars, and portions thereof, are tightly and efficiently layered one over another. Upon actuation of a retention mechanism, the stored energy in each of the collapsed helical filars initiates antenna deployment whereby the guide elements accurately and reliably control the movement and final position of a corresponding helical filar.

Abstract: An energy transmission arrangement is formed as a subarray panel which emits a microwave energy signal to a target location on the basis of a pilot signal received from the target location. The subarray panel includes a transmission antenna divided into a subarray having a plurality of antenna elements for transmission of the energy signal. The subarray panel further includes pilot signal receiving antennas and thus each subarray panel may function independently and may thus be made lighter and more compact.

Abstract: An array antenna especially adapted for spacecraft use includes a support frame made up of intersecting beams which form an "eggcrate" of square openings. A plurality of subarrays or radiating tiles are dimensioned to fit within the openings. Distortion of the support frame due to external forces, or due to expansion and contraction of the radiating tiles, is accommodated andor resisted by a four-point mounting arrangement for each tile. Each mounting is located on the center of the sides of the radiating tile, and the corresponding center of the side of the opening in which it fits. Each mounting consists of a thin, flexible mounting beam, extending parallel to the associated support beam, and fastened to the support beam at the ends of the mounting beam. The center of the side of the tile is fastened to the center of the flexible support beam, so expansion and contraction of the tile are compensated by bending of the flexible beam.

Abstract: Antenna assemblies and stowage and restraint system thereof, comprising at least one dual band reflector having overall L-band-reflective properties and having a central stiffened Ku-band-reflective area having high reflector surface accuracy surrounded by a flexible annular area having L-band reflective properties. The reflector also has a support hingedly attached to a spacecraft body for deployment between a stowage position in which it is pivoted and restrained up against a face of the spacecraft body and the flexible annular reflector areas partially flexed therearound, and a deployed position in which it is enabled to relax and return to extended, parabolic condition.

Abstract: An advanced active element phased array satellite antenna is disclosed. Incorporating these novel antenna systems on a constellation of low Earth orbit spacecraft, allows phone customers worldwide to communicate through a system whose switching intelligence resides on orbit, bypassing traditional land-based networks, and offering a revolutionary expansion of communications potential. The present invention utilizes electronic beam steering is utilized to provide extremely high gain signals. In one preferred embodiment, a satellite (S) includes an Earth-facing array (10) of hexagonal antenna facets (12), mated together along their sides to form a slightly flattened, hemispherical shell. The antenna array (10) is connected to two rectilinear, unfurled, solar panels (P). The antennas (10) transmit and receive signals from terrestrial units located within the footprints (14) of the beams (11).

Abstract: An antenna array for use in space includes an optical solar reflector (OSR)-like structure (310, 510), with sheet of transparent dielectric material (320, 520) and a metallic mirror (322, 522) formed on the sheet. In order to allow the individual antenna elements to radiate electromagnetic energy, the metallic mirror contains apertures (330, 530) which, in one embodiment, define the antenna elements, and which, in another embodiment, are registered with the antenna elements of the array. Where the mirror exists, insolation is reflected, and the heat gain from insolation is minimized. At the locations of the apertures in the mirror, insolation passes through the OSR-like structure, which may tend to increase the temperature of the structure. According to the invention, the apertures are covered with a thin layer (370, 570) of semiconductor material such as germanium or silicon, which does not affect the electromagnetic energy flow.

Abstract: A method for stowing a unitary flexible antenna reflector 10 in a confining envelope and deploying the reflector from the envelope. In a most general sense, the invention includes the steps of: a) applying a deforming force to diametrically opposed positions 16 and 18 near an edge of the reflector 10 to place the reflector in a deformed state; b) maintaining the reflector 10 in the deformed state until deployment; and c) releasing the reflector 10 from the deformed state. In a specific embodiment, the step of maintaining the reflector 10 in a deformed state includes the step of attaching a restraining element between the diametrically opposed positions on the edge of the reflector which is released on deployment.

Abstract: An energy receiving satellite has a curved outer surface on which a plurality of energy signal reception antenna elements are arranged. The satellite may also include a pilot signal generator and a plurality of pilot signal transmission antennas arranged at intervals around the curved outer surface of the satellite. The curved surface is composed of a plurality of curved panels which may be folded in an overlapping condition or unfolded such that the panels are disposed adjacently in a circular arrangement.

Abstract: An antenna has one feed for an S-band electromagnetic signal, and a second feed constructed as an array of radiators to service two C-band signal channels. A subreflector having a microwave frequency selective surface (FSS) is placed in front of a main reflector. The C-band feed is constructed of an array of square aperture horns joined by separate transmit and receive barline beam-forming networks, and a meanderline polarizer to produce circularly polarized radiation patterns. Tapered ridges extend longitudinally along inner wall surfaces of each of the horns to provide increased bandwidth to the C-band feed. The frequency selective surface is constructed, typically, of a generally planar substrate of material transparent to electromagnetic radiation, and numerous metallic, generally annular, radiating elements, or resonators, arranged on the substrate in an array of repeating nested sets of the radiating elements.

Abstract: An antenna (70) includes a first sub-structure (72) having a major plane that is oriented at a first angle (for example, 90.degree.) with respect to an axis (normal) that is perpendicular to the surface of the earth. The antenna also includes a plurality (for example six) of second sub-structures (74) individual ones of which have a local major plane that is disposed at a second angle (for example, 45.degree.) to the major plane of the first sub-structure. Each of the plurality of sub-structures have an outwardly pointing normal from the local major plane that is oriented at a third angle (for example, 60.degree.) around the axis from an outwardly pointing normal of an adjacent one of the sub-structures. The outwardly pointing normal of each of the plurality of sub-structures is disposed so as to point away from the axis. At least one antenna element (76) is supported by the first sub-structure and by each of the plurality of second sub-structures.

Abstract: An array antenna mounted on a spacecraft in its stowed state. After the spacecraft is launched in a predetermined position or on a predetermined orbit, the array antenna is extended to a flat plate form or a curved surface form. The array antenna has a structure that a plurality of subarrays are connected by plate springs or the like. The array antenna is extended in a kite form by using cables for connecting a spacecraft body and the subarrays or is extended by using an extension pole mounted on the spacecraft body. Each subarray includes a variable phase shifter to switch a shape and a direction of a directivity beam. A feeder line, a power supply line, a control signal line and the like connect the spacecraft body and each subarray.

Abstract: Equalized offset fed east and west shaped reflectors (12) and (14) and technique for producing the same are provided herein. A first shaped reflector (12) has a first shaped reflective surface (3) formed to provide a first shaped beam radiation pattern (22). Dimensional deviations such as deviations (X) and (Y) are measured between the first shaped reflective surface (13) and a parent surface (30). A second shaped reflector (14) is formed with a shaped reflective surface (15) which has dimensional deviations superimposed on the other side of the parent surface (30). The second shaped reflector (12) is rotated 180 degrees relative to the first shaped reflector (14). The first and second shaped reflectors (12) and (14) are then placed in a configuration opposite one another and have shaped beam radiation patterns (22) and (24) which are substantially equal to one another. In addition, feed horns (18) and (20) are operatively coupled to the first and second shaped reflective surfaces (13) and (15) respectively.

Abstract: An RF-transparent sunshield membrane covers an antenna reflector such as a parabolic dish. The membrane includes a single dielectric sheet of polyimide film 1 mil thick. The surface of the film facing away from the reflector is coated with a layer of semiconductor material such as vapor-deposited germanium having a thickness in the range of 200 .ANG. to 600 .ANG.. In another embodiment of the invention, the surface of the film facing the reflector may be reinforced by an adhesively attached polyester or glass fiber mesh.

Abstract: An RF-transparent sunshield membrane covers an antenna reflector such as a parabolic dish. The membrane includes at least two dielectric sheets of polyimide film 1 mil thick. The surface of the outer film facing away from the reflector is coated with an electrically semiconductive coating such as vapor-deposited germanium having a thickness in the range of 200 .ANG. to 600 .ANG.. A member, such as a glass fiber mat, may be located in the space between the two dielectric sheets for maintaining the sheets in spaced-apart relationship. In another embodiment of the invention, the surface of the film facing the reflector may be reinforced by an adhesively attached polyester or glass fiber mesh.

Abstract: A device, particularly a missile, includes a body having an appendage, e.g., a wing, normally folded in an inoperative position and to be unfolded to an operative position when the body is accelerated in the direction of the longitudinal axis of the body. The appendage is pivotally mounted about a first pivot axis extending perpendicularly to the longitudinal axis of the body, and also about a second pivot axis extending parallel to the longitudinal axis of the body. The center of gravity of the appendage is outwardly of the first pivot axis in the folded condition of the appendage such that the acceleration of the body produces a moment pivotting the appendage about the first pivot axis.

Abstract: According to the present invention, a thin, lightweight active phased array antenna panel is provided that efficiently radiates heat and arbitrarily polarized microwave signal power. The active array panel also efficiently reflects solar power so as to minimize solar heating. The active array panel includes a plurality of subarray elements each of which includes a plurality of aperture coupled patch radiators. The exterior surface of the subarray element is covered with silvered second surface mirrors to provide efficient radiation of heat in the presence of sunlight. A microstrip feed network in the subarray element is embedded in a dielectric material with a high thermal conductivity to efficiently distribute heat. The active array further includes an electronics module for each subarray element. The electronics module contains a solid state power amplifier, phase shifter and associated electronics mounted in a housing made of material with high thermal conductivity.

Abstract: An RF-transparent sunshield membrane covers an antenna reflector such as a parabolic dish. The blanket includes a single dielectric sheet of polyimide film 1/2-mil thick. The surface of the film facing away from the reflector is coated with a transparent electrically conductive coating such as vapor-deposited indium-tin oxide. The surface of the film facing the reflector is reinforced by an adhesively attached polyester or glass mesh, which in turn is coated with a white paint. In a particular embodiment of the invention, polyurethane paint is used. In another embodiment of the invention, a layer of paint primer is applied to the mesh under a silicone paint, and the silicone paint is cured after application for several days at room temperature to enhance adhesion to the primer.

Abstract: A laminate (10) which is transparent to radio frequency emissions, useful as a thermal control and electrostatic discharge surface, for example for protecting spacecraft antenna hardware, comprises a conductive layer (12) for dissipating electrostatic charges and a thermal control layer (24) for reflecting thermal radiation and reducing the effect of temperature variations on one side of the laminate on the region on the other side of the laminate. In a preferred embodiment, the conductive layer (12) preferably comprises a semiconductor, such as germanium. The thermal control layer (24) comprises a film layer (14), for example of polyimide film, a mesh layer (16), for example of polyamide fabric, attached to the film layer (14), and a thermally reflective coating (20), applied to the mesh layer (16) for aiding the conductive layer (12) and thermal control layer (24) in reflecting radiation.

Abstract: A compact, reliable, paraboloid shaped assembly 7 is used as a reflector 7 on a satellite. The apparatus 7 is assembled from multiple panels 2, 3, 4, which connect to a central base 1 using hinges 20, 21. The apparatus 7 is compacted by rotating some or all of the panels 2, 3, 4 to be adjacent to one side 12 of the central base in stages, such that alternate panels 3 are rotated first. Folded onto these panels 3 are the remaining backwards-folding panels 2. The panels 4 which are not rotated backwards are then rotated forwards, completing a highly compact design. For deployment, the panels 2, 3, 4 are rotated in the reverse order and direction in which they were compacted. Latches 10 connect adjacent panels 2, 3, 4 and hold the panels 2, 3, 4 in the deployed position.

Abstract: A system and method for "power beaming" energy from a source at high frequencies and rectifying such energy to provide a source of DC energy is disclosed. The system operates at a frequency of at least 10 GHz and incorporates a rectenna array having a plurality of rectenna structures that utilize circuit elements formed with microstrip circuit techniques. Each rectenna element is associated with a resonating cavity structure.

Abstract: An antenna system is provided having a plurality of individual antenna elements located on a foldable platform. The antenna elements are appropriately phased to yield a desired radiation pattern. The platform has a plurality of light-emitting devices mounted at predetermined locations on the platform. Light from each of the light-emitting devices passes through a corresponding window assembly on a hub. A biconical reflector within the hub directs rays of light from all the light-emitting devices through a telescope and a system of mirrors which focus the rays so as to form images on photodetector arrays. The images formed by the focused optical signals relate to the actual configuration of the platform.

Abstract: A stowable and self-deployable array antenna includes flat, rectangular antenna panels hinged side-by-side so that when deployed they are coplanar, and they fold like an accordion for stowing. The deployed array antenna is stiffened by lateral stiffening panels hingedly attached to every other hinge between antenna panels, and to the unhinged ends of the antenna panels. Foldable longitudinal stiffening panels are hinged between adjacent lateral stiffening panels. Each hinged connection includes a pair of thin spring elements, corresponding to a portion of a cylinder. The two spring elements of each hinge are spaced apart with their concave sides facing, and with the axes of the defining cylinder parallel. The hinge pivots, when the spring elements buckle, about a line orthogonal to a line extending between the cylinder axes. The hinges are used as the structural elements of self-deployable masts. The mast may have a polygonal cross-section.

Abstract: A satellite adapted to be spin-stabilized in geostationary orbit having, coaxial with a spin rotation axis, a satellite surrounded with a solar generator. At least two equipments including an apogee maneuver system are disposed along the rotation axis. A set of generally annular antennas including at least one picture transmission antenna is disposed on one of the NORTH and SOUTH faces of the satellite so as to leave at its center a cylindrical space along the spin rotation axis to house one of the equipments. The other of the equipments is disposed on the other of the NORTH and SOUTH faces.

Abstract: An object mounted on a carrier constitute a rotationally free system such as a telescope on a space vehicle. A separation vector is directed from the center-of-mass of the carrier to the center-of-mass of the object. The object is rotated through a selected angle thereby defining a rotation vector. Simultaneously the object is translated so as to displace the object center-of-mass through a translation distance in a direction such that mathematically crossing the translation vector into the separation vector results in a further vector having the same direction as the rotation vector. A formula is provided for the translation distance in order that the object may be rotated without counter-rotation of the carrier.

Abstract: A choke-slot ground plane and antenna system 30 is disclosed. In one embodiment the choke-slot ground plane and antenna system 30 includes a monopole antenna 44, a ground plate 36 having a plurality of concentric annular grooves 38a-c. Other embodiments include a ground plane 36 having varying size grooves to 38a-l, a ground plane having grooves having filled with dielectric material 38a'-c', a ground plate having a broadened bandwidth and having a series of first and second-type grooves 34a-c and 38a"-c", and a ground plate having a frusto-conical shape 36a and 36b.

Abstract: A system and method for power beaming energy from a source at high frequencies and rectifying such energy to provide a source of DC energy is disclosed. The system operates at a frequency of at least 10 GHz and incorporates a rectenna array having a plurality of rectenna structures that utilize circuit elements formed with microstrip circuit techniques.

Abstract: The present invention is a microwave radiometer for passive microwave remote sensing of the earth's surface. This microwave radiometer is formed as a cross array including a vertical linear array pointed toward nadir and a perpendicular horizontal linear array. A beamformer is coupled to each array for forming a plurality of adjacent fan beams. A plurality of cross correlators produce overlap beams from the overlap of each pair of vertical and horizontal-array fan beams. This arrangement receives microwave energy from the earth at a constant incidence angle, a feature useful in passive microwave sensing. This microwave radiometer provides acceptable radiometric sensitivity and a spatial resolution while requiring less collecting area and thus much less mass than a dish antenna with the equivalent spatial resolution and needing no moving parts.

Abstract: The figure of an unfurled antenna comprising a radio-frequency reflective fabric (10) is mapped and controlled by a system comprising a plurality of light-emitting devices (14, 15) mounted at precisely specified locations on ribs (11), which support the fabric (10). Light from each of the light-emitting devices (14, 15) passes through a corresponding window assembly (16) on a hub (12), which support the ribs (11) and also houses a telescope of the Schmidt-Cassegrain type. A biconical reflector (27) mounted within the hub (12) directs rays of light from all the light-emitting devices (14, 15) to a primary mirror (21) of the telescope, from which the rays are reflected to a secondary mirror (22), which focuses the rays so as to form images on photodetector arrays (31) and (32). The images formed on the photodetector arrays (31) and (32) are swaths of light, which cross the photodetector arrays (31) and (32) at positions determined by the actual positions of the light-emitting devices (14, 15).

Abstract: A horn type microwave antenna includes a main reflector and sub-reflector that are supported in proper spaced relationship by flexidigit robotic manipulators, multisection arms that are capable of positional changes, whereby the supports may be changed in position responsive to the application of control voltages. At least a portion of the manipulators include piezo electric actuators, permitting rapid adjustment of the reflectors' position.

Abstract: A satellite communications system employs separate subsystems for providing broadcast and point-to-point two-way communications using the same assigned frequency band. The broadcast and point-to-point subsystems employ an integrated satellite antenna system which uses a common reflector (12). The point-to-point subsystem achieves increased communication capacity through the reuse of the assigned frequency band over multiple, contiguous zones (32, 34, 36, 38) covering the area of the earth to be serviced. Small aperture terminals in the zones are serviced by a plurality of high gain downlink fan beams (29) steered in the east-west direction by frequency address. A special beam-forming network (98) provides in conjunction with an array antenna (20) the multiple zone frequency address function. The satellite (10) employs a filter interconnection matrix (90 ) for connecting earth terminals in different zones in a manner which permits multiple reuse of the entire band of assigned frequencies.