Abstract: A multiple beam space antenna system for facilitating communications between a satellite switch and a plurality of earth-based stations is shown. The antenna is deployed after the satellite is in orbit by inflation of a raft-type supporting structure which contains a number of antenna horns. These antenna horns are oriented in substantially concentric circular groups about a centrally located antenna horn. Each of the antenna beams projects an area on the earth. Each of the areas of the beams are contiguous. As a result, one large area is subdivided into many smaller areas to facilitate communications. In addition, a lens may be employed to focus the beams of the horn antennas.

Abstract: A telescopic mast system has a base tube, a plurality of axially movable coaxial inner tubes nestable successively within each other and within the base tube, and a winch supported at the lower end of the base tube with a pair of preferably wire ropes driven thereby for extending and retracting the inner tubes. The base and inner tubes have collars at their respective ends, the collars of adjacent tubes engaging each other to limit extension thereof and to provide additional structural support during application of bending loads on the mast system. The ropes are connected to pulleys mounted near or within tube collars so that the ropes and pulleys are totally enclosed within the mast system. As the winch is rotated in one direction, the ropes axially move the inner tubes from a nested or stowed position within the base tube to a fully vertically extended operational position.

Abstract: An antenna array with circular symmetry made up of an array of cylindrica shaped printed circuit elementary antennas. It is made up of small radiating sources which are placed in superposed circles on a cylindrical surface. The sources are distributed at constant angular intervals on the circles. They have little coupling between themselves. On each circle of sources, they are energized in phase and with the same amplitude. An angular phase shift can be provided between the group of sources on a circle and those of another circle. The antenna can be energized by a three-layer printed circuit line. It can be made up by an array of doublets folded into sheets. Inside the cylinder the transmitter is installed to which is applied a signal to be transmitted and which supplies the modulated carrier to the array of radiating sources.

Abstract: An equal power amplifier system (100) for amplifying a plurality of signals for transmission by an active phase array antenna (20), and a compact plural level beam-forming network (98) for forming a plurality of such signals, for example on excitation patterns for frequency scanned virtual beams, are disclosed. The amplifier system uses at most only a few sizes of power amplifiers (130, 134) to amplify efficiently numerous signals having significantly different amplitudes. This is accomplished by distributing the task of amplifying signal pairs (A.sub.i, B.sub.i) composed of one large amplitude signal and one small amplitude signal to an equal power amplifying apparatus (130; 230), which includes two hybrid couplers (236, 238) and two equally sized power amplifiers (232, 234). The first hybrid coupler (236) divides the two signals (A.sub.i, B.sub.i) for input into the two power amplifiers.

Abstract: A self-erecting antenna includes a base for pivotally mounting two oppositely extending pi-shaped dipole antennas that are symmetrically positioned with respect to a medial ground plane attached to the base. Two sheets of flexible KAPTON material are each connected at opposite edges thereof, between the base and a respective dipole antenna, enabling collapsed folding of the antenna for storage. When the dipole antenna is free to move, the KAPTON sheets act like springs to erect the dipole antenna to a deployed condition.

Abstract: The invention is a system for automatically controlling the surface contour of a deployable and restowable antenna 11 having a mesh reflector surface 26 supported by a circular, folding hoop 12 affixed to a central, telescoping column 14. The antenna 11, when deployed, forms a quad-aperture reflector with each quadrant A-D of the mesh surface 26 shaped to provide an offset parabolic RF reflector.The hoop 12 is supported and positioned by quartz support cords 12 attached to the top 22 of column 14 and by lower graphite hoop control cords 23 that extend between the hoop 12 and base 24 of the column 14. The antenna 11, an RF reflective surface 26, is a gold plated molybdenum wire mesh supported on a graphite cord truss structure that includes the hoop control cords and a plurality of surface control cords 27 attached at selected points on the surface 26 and to the base 24 of column 14.

Abstract: A plurality of small segments stowed in a compact stack are assembled, essentially automatically, into a large construction surface, such as a flat or parabolic reflector.

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.

Abstract: The antenna comprises a parabolic reflector (1) and a primary source (2). The reflector (1) comprises a first grating of conductor wires (7) and a second grating of conductor wires (8) which are orthogonal to the wires of the first grating, and with both gratings constituting elliptical reflective surfaces. The sizes of the major and minor axes of the ellipses are determined in such a manner that both operating frequencies of the antenna have identical coverge zones on the surface of the globe.

Abstract: A plurality of indexing brackets having indexing apertures are secured to a retractable boom in spaced relation. A like plurality of indexing bulkheads are hinged to a foldable panel array (or collapsible spiral antenna) at spaced hinge axes. The bulkheads have indexing prongs which engage the indexing apertures, the brackets pullings the bulkheads therewith as the indexing apertures and prongs engage. Force contact spring motors urge the brackets and bulkheads together in the engaged state. Alignment guides align the brackets and bulkheads during engagement and disengagement of the indexing apertures and prongs.

Abstract: An antenna reflector having a parabolically curved reflecting surface is formed of a cellular ceramic material having ceramic fibers fused together in a rigid cellular structure. The body is formed by bonding or fusing a mass of silicon dioxide fibers together at their points of intersection with a fusing agent such as boron nitride in a sintering process, resulting in a fused array of fibers with cellular porosity intentionally distributed through the body to reduce its density. Other types of ceramic fibers can be used either alone or in combination with the silicon dioxide fibers. The antenna reflector finds particular utility in parabolic antennas for satellite microwave communications systems.

Abstract: A waveguide-fed horn structure includes a constraining mechanism having an extremely high degree of dimensional stability over a wide thermal range. The constraining mechanism comprises a composite graphite honeycomb structure that forms a support backing for the waveguide feed and for the conductive surface sections of the horn radiator. The conductive surface of the horn radiator is supported on a first section of graphite epoxy laminate while a second section of graphite epoxy laminate supports the honeycomb backing and is bonded to the first section of laminate, thereby effectively surrounding the feed-horn structure with a thermally tolerant, physical distortion constraining support.

Abstract: An antenna reflector, for example for a satellite or spacecraft, has ribs urnalled to a central body by a first journal axis. Each rib has a radially inner section tiltable and lockable relative to the central body, and a radially outer section journalled to the inner rib section at a second journal axis for tilting and locking the outer rib section relative to the inner rib section. A motor driven cable drive and respective pulleys are so arranged that the inner rib sections are first partially unfolded before the outer rib sections begin to be unfolded. The outer rib sections then are moved faster than the inner rib sections so that both rib sections reach the fully unfolded state substantially simultaneously. The folding takes place in the reverse order, whereby the outer rib sections are folded first. The reflector netting is stretched out only after the ribs have been locked into the unfolded state.

Abstract: A parabola antenna reflector incorporating an deploying apparatus of the invention has a disk shape having a predetermined radius of curvature. The reflector has a cross-shaped first reflector portion which extends to a peripheral portion of the reflector in the longitudinal direction, a pair of second reflector portions axially held at two sides of the first reflector portion to oppose each other and biased to open, and two pairs of third reflector portions axially held at two sides of each of the second reflector portions to oppose each other and biased to open. The pair of second reflector portions are held by a first locking mechanism in a folded state, and the two pairs of third reflector portions are held by second locking mechanisms in a folded state. The holding state of the second locking mechanisms is released when the folding state of the first locking mechanism is released and the second reflector portions begin to deploy.

Abstract: A pivoting joint connects two rectangular waveguides, connecting transmission-reception equipment on board a satellite to an antenna, which is only opened out when the satellite has been placed in orbit. These waveguides comprise a fixed section and a moving section, pivoting about the longitudinal axis common to the two sections. They issue or open out in facing manner on two parallel planar faces separated by a non-zero distance, but which is very small compared with the wavelength. One of these faces has a quarter-wave trap ensuring the radio seal of the joint. An abutment defines the position in which the two guides are in an extension of one another. When the satellite reaches orbit, antenna is opened out and the joint pivots to this position.

Abstract: An antenna reflector structure of the offset-fed type which is suitable for use on spacecraft. The reflector structure includes a central boom, a number of spaced ribs on the boom, an RF reflective mesh layer adjacent to the outer, transverse peripheral edges of the ribs, and contoured angle members for securing the mesh layer to the ribs to provide a specific contour for the reflector surface defined by the mesh layer. The boom can be of one-piece construction or formed from telescoped segments. The reflector structure is deployable and furlable. Several embodiments of the reflector structure are disclosed.

Abstract: A column longeron latch assembly 72 provides the securing mechanism for the deployable, telescoping column 12 of a hoop/column antenna 10. Column 12 is an open lattice structure with three longerons disposed 120.degree. apart as the principle load bearing member and is deployed from a pair of eleven nested bays 22, 23 (FIG. 2) disposed on opposite sides of a center section 21 under the influence of a motor-cable-pulley system (FIGS. 3 and 4). Longeron latch 72 is a four bar linkage mechanism using the over-center principle for automatically locking the longeron sections into position during deployment and serves to unlock the sections when antenna 10 is to be re-stowed. A spring pack 61 disposed in an end of each longeron serves to absorb stress forces on the deployed column through the cam head piston and abutting latch from an adjacent longeron.

Abstract: The present invention is directed to a multibeam antenna reflector distortion compensation system comprising at least one remote reference radio frequency transmitter cooperating with a feed cluster of a beam forming network which includes one central and at least two peripheral feed elements, means for producing error signals including a circuit for consecutively connecting each peripheral cluster feed element to one input of an adding circuit, and the central feed element to the other input after appropriate attenuation and phase compensation of the central feed signal, and means for down-converting linear and non-linear distortion correction signals based on the down-converter output.

Abstract: A collapsible-expandable truss structure 16 including first and second spaced surface truss layers (18, 20) having an attached core layer 22 is disclosed. The surface truss layers are composed of a plurality of linear struts 40 arranged in multiple triangular configurations with each linear strut being hinged at its center 41 and hingedly connected at each end thereof to a nodular joint 25. A passive spring 64 serves as the expansion force to move the folded struts from a stowed collapsed position to a deployed operative final truss configuration. Damper 62 controls the rate of spring 64 expansion for synchronized deployment of truss 16 as the folded configuration is released for deployment by restraint belts 72a and 73a synchronously extending under the control of motor (71) driven spools 72 and 73.

Abstract: A method and apparatus for broadcasting, transferring and disbursing infotion from space to earth uses sunlight as the carrier. An orbiting platform receives sunlight and modulates it with electromagnetic signals carrying the information beamed up from an earth station, communications satellite or aircraft. The modulated sunlight is directed to a designated area on earth from the orbiting platform where it penetrates clouds as well as seawater to reach surface and submerged receiving stations including submarines.

Abstract: The invention relates to multi-mission orbital spacecraft of the kind comprising a platform and several different payloads including several telecommunication antenna feed systems.The problem is to avoid antenna interference, obtain bigger effective antenna aperture, avoid the necessity for replacing main antennae when replacing payloads, and make maximum use of longer platofrm life.In accordance with the invention, the antenna system comprises a common primary reflector which is a permanent integral part of the platform while the feed systems are mounted on the payloads, which may be launched separately, and are assembled with the platform to cooperate with the common platform antenna system in operation.The invention is mainly applicable to multi-mission satellites.

Abstract: A NAVSTAR satellite has a navigation antenna array beamed toward the earth. A communications antenna array for communicating with other satellites requires a pattern null near the axis and high gain to the sides with minimum losses. This is achieved with a dipole ring array comprising eight elements surrounding the navigation array. The ring has a diameter of 1.1 wavelength, and is fed with equal amplitudes and a third mode phase progression, which produces good circular polarization in the far field. For a different sized dipole ring, there will still be an optimum phase distribution which will give good circularly polarized patterns.

Abstract: A communications spacecraft reflector is accurately positioned with respect to its feed assembly by a thermally stable stiff mounting platform which is secured in distortion isolation from the rest of the spacecraft. A yaw actuator can move the platform about an axis parallel to the spacecraft yaw axis.

Abstract: The invention relates to a mounting device for supporting a component, especially a mirror or an antenna reflector in a spacecraft. The device comprises a combination of flexible blades disposed between the support, and between the intermediate piece and the component.

Abstract: A holding and releasing system provides temporary connection between a movable and a stationary part which are to be separated during the specific use thereof. It comprises a supporting foot connected to the fixed part, a rocker link hinged to said foot, a movable support hinged to said link, a sheaving bracket hinged to another end of said link; said link occupying two positions, i.e. a locking one in which the movable support bears on one face of the movable part, while the free end of the sheaving bracket bears on the other face of said movable part, to block the latter in a precise position, and a release position in which the movable support and said bracket are in a retracted position thereby releasing the movable part. The system is used especially in the space vehicle domain.

Abstract: An antenna apparatus for use in space which is foldable into a small package for storage in a space vehicle. The antenna apparatus utilizes a plurality of hinged members and diagonal tapes forming parallelogram frames, two opposite sides of which are hinged at the center to fold the frames in a given plane. Similar frames are hinged on the first frames in a second plane whereby a plurality of cubes are formed when all are unfolded.

Abstract: Heating elements and temperature sensing devices are positioned in diametrically opposed pairs along a tubular boom extending outwardly from a spacecraft. As temperature differentials are detected across the diameter of the boom, current is selectively applied to the heating element on the cooler side of the boom to equalize the temperature and prevent boom distortion. In another application, current may be selectively applied to a heating element to cause bending of the boom to achieve a desired positioning of the tip portion of the boom.

Abstract: An extendible tubular boom includes a metallic ribbon which is prestressed to assume a rigid tubular shape when extended and which can be flattened and coiled for storage, and a plurality of conductive foil strips fixed to the ribbon which provides electrical paths between sensors located at the tip of the boom remote from the spacecraft and electronics located within the spacecraft. Remote positioning of sensors permits the measurement of parameters of the local plasma without the perturbing effect of the presence of the main body of the spacecraft. The conductive foil strips are electrically isolated from the metallic ribbon comprising the boom structure by a layer of insulating material. Both the foil strips and the insulating layer are sufficiently flexible so as to withstand the transverse and longitudinal stresses encountered as the boom is furled and unfurled.

Abstract: A lightweight single layer microstrip membrane antenna for space radar applications which, in an exemplary application, is adapted to be furled on a spool and carried into space by a space shuttle orbiter where it is easily unfurled to form an antenna. The membrane antenna includes gore sections which are connected by metal mesh members that are folded in the furling process to avoid folding of the gore sections. The metal mesh members may also act as primary power busses for suitable transmit/receive antenna modules that are connected to series strings. Current regulators and zener diodes are connected in the strings of antenna modules to provide for continued operation of the antenna in the event of failure of antenna modules.

Abstract: Disclosed is an expandable panel and truss structure capable of being stowed in a storage container (canister) for transportation into space and deployed to form structures such as antennas, solar panels or similar space or terrestial structures. The antenna formed comprises the panels stored as hinged pairs (sets) folded in accordian-like fashion together with the expandable trusses and other devices necessary for antenna space operation, such as attitude control and antenna feed. The panel sets are deployed from the canister to form a toroidal ring, circular in cross-section when deployed, for supporting the antenna lens and to form a feed support boom utilizing the canister as part of the antenna structure. The canister is connected to the ring and support boom in the deployed state by the expandable trusses. A fully automatic system is included for deploying the antenna and for holding the antenna structure in its deployed state.

Abstract: A lightweight, efficient, microwave power transmitting antenna is disclosed, suitable for use in a space borne transmitter for beaming solar generated electrical power down to earth based receiving antennas. The space borne antenna structure is formed by modules that are structurally integrated into a multimodule antenna array. Each module comprises a rectangular framework of limited depth having rigid sides circumscribing a generally open region in which a plurality of spaced parallel single wire Goubau transmission lines are strung to create a "see-through" harp-like configuration. A Klystron powered feed wave guide is disposed as one structural side of the module for exciting standing electromagnetic waves on the plurality of Goubau lines. Printed circuit Yagi endfire radiators are supported on dielectric webs disposed in juxtaposition with the Goubau lines for being synchronously excited by the standing waves on such lines.

Abstract: A structural array and electrical rotary joint for transmitting an electrical power between large space structures having relative rotational movement therebetween is disclosed as including large support framework structures A and B which rotate relative to one another about a common axis of rotation X. A rotary interface joint 14 is defined between the structures A and B. A cylindrical hub member C is carried by the structure A and a cylindrical hub member is carried by support structure B with hub member C being received concentrically within hub member D for relative rotation. Tension connecting cables connect hub member C and hub member D with their associated outer structures A and B whereby relative rotational movement between structures A and B is transmitted to the cylindrical hub members for unitary motion therewith.

Abstract: An agile payload orientation system for a space satellite comprises a three-axis gimbal (30) for coupling an appended body (20) containing the payload (24, 25, 26, 27) to a main body (10) of the satellite. The appended body (20) also contains moment control gyroscopes (29), which are responsive to external command for changing the orientation of the appended body (20) relative to an inertial reference. The gimbal (30) comprises three separate torquer-resolver units (31, 32, 33), which are connected to each other in series so that their axes are mutually orthogonal to each other and coincide at a single point (34) located at the center of mass of the appended body (20). Since the center of mass of the appended body (20) does not move when the appended body (20) is rotated about the axis of any of the torquer-resolver units (31, 32, 33), a change in orientation of the appended body (20) can be made without disturbing the orientation of the main body (10).

Abstract: The present invention relates to the orientation of antennae on a satellite possessing at least one antenna comprising a horn rigidly connected to the body of the satellite, a movable reflector mounted on an orientable platform and at least one radio-frequency sensor in the horn using said antenna to control the orientation of said reflector. The invention consists of: using a signal characterizing the pivoting of the orientable platform with respect to the body of the satellite to orient said satellite correctly with respect to the reflector in order to limit the pivoting of said platform; using the signals from at least one earth sensor in the same way as the signals from the radio-frequency sensor to control said reflector, so as to orient the beam towards the point sighted on the earth. The invention is particularly useful for the control of the orientation of antennae, particularly on a satellite.

Abstract: The antenna system employs a parabolic reflector fed by an offset feed array of circular wave guides located substantially at the focus of the parabolic reflector, but offset from the axis thereof. A plurality of aperture tuning mechanisms disposed at the mouths of the circular waveguides of the waveguide feed array, and having physical lengths much shorter than one wavelength at the frequencies involved, are provided to reduce cross-polarization and mutual coupling between adjacent feeds. The short resonant length of these tuning mechanisms, and their shape which is chosen to generate the TM.sub.11 mode E-field contour line ensures that they are effective over a broad bandwidth of as much as 20% or more. Within this bandwidth, they act as inductive suppressors to control both cross-polarization and mutual coupling between adjacent feeds.

Abstract: The present invention relates to an antenna arrangement capable of generating one or more linearly scanning spot beams which are scanned over separate strip portions of the entire field of view of the antenna. The antenna arrangement comprises an optical system comprising an aperture and a focal plane, and a novel feed arrangement. The feed arrangement comprises a separate linear phased array disposed within a separate rectangular waveguide section for each linear scanning beam desired. An offset curved reflector, disposed in each waveguide section, converts a linearly scanning planar wavefront generated by an array into a converging beam forming a linearly moving point source on the antenna's focal plane with the principle ray of each instantaneous wavefront being directed at the center of an image of the aperture of the optical system as seen by the feed arrangement.

Abstract: An offset antenna and feed combination for use in a satellite communication system is disclosed wherein an array of adjacent microwave energy feed elements is disposed within a predetermined shape on the focal surface of the antenna for delivering electromagnetic energy to a remote, correspondingly shaped zone. Electromagnetic energy beams are selectively radiated towards predetermined areas of the overall remote zone by associated cluster groups of feed elements typically arranged as a minimum of one central and six surrounding feed elements. Additionally, each surrounding type of feed element of a cluster may be shared by two or more overlapping clusters, the overlapping clusters generating contiguous beams of electromagnetic energy in different frequency subbands.

Abstract: Microwave energy feed elements for launching essentially linearly polarized beams in a satellite communications system are oriented in the satellite's antenna so that the polarization directions of the feed elements form a rim and spoke configuration. The vertical polarizations are arranged to extend radially from a point on the antenna's focal surface which images the point on the surface of the celestial body directly below the satellite. Horizontal polarizations are arranged concentrically about the subsatellite image point. Electromagnetic energy launched from the feed elements will reach the surface of the earth at planes of incidence which are locally vertical and horizontal, thereby minimizing cross-polarization coupling between the orthogonally polarized signals due to such energy passing through precipitation.

Abstract: A multibeam communications satellite uses a dish-shaped reflector whose surface is a surface of revolution generated by rotating a plane parabola about an axis of revolution located in the plane of the parabola but angularly displaced from the axis of symmetry thereof. The line of revolution of the focal point of the parabola defines a focal circle, and a feed located on the focal circle will illuminate an area lying on a circle near the edge of the earth's apparent disc. Since every plane in which the axis of revolution lies is a plane of symmetry, the antenna exhibits good cross polarization cancellation, making the satellite particularly useful in frequency reuse communications systems.

Abstract: A deployable ground plane antenna for use aboard a satellite or the like, with the antenna and erection mechanism being compactly stowable within the confines of a launch vehicle prior to and during launch thereof. After ejection of the satellite from the launch vehicle, the ground plane antenna self-deploys on removal of a single cable restraint. The mesh-like ground plane or reflector is pulled into a deployed planar configuration by flexible rods which carry the ground plane and which are spring-loaded to provide erection force.

Abstract: A redundant microwave configuration providing a highly flexible routing of a plurality of inputs to a plurality of outputs is characterized by at least two switching layers wherein each switching layer comprises a plurality of four port switches and the switches in at least one of the switching layers are connected in a ring, corresponding switches in the layers being interconnected. This redundancy configuration is not limited to microwave applications only but could be implemented at all other frequencies. One microwave configuration employs 2N amplifiers between said switching layers as building blocks to provide N inputs to N antenna ports. This configuration allows any combination of (m-N) amplifier failures without loss of service, where N .ltoreq. m .ltoreq. 2N. In other configurations, only one type of switch is used and fewer than 2N amplifiers are used for N inputs and N outputs.

Abstract: A synthesis technique for constructing curved wave guide arrays in spherical sections to provide a pencil or squinted beam in a desired direction in which a plurality of slotted wave guides are bent to a radius of curvature corresponding to circles cut through a sphere and interconnected to a cap conforming thereto with each of the wave guide radiating arrays constructed as anti-phase slotted arrays with variable slot spacings, the location of the slots being dependent upon the phase correction required to generate a pencil beam.

Abstract: A supporting structure that deployed resembles a spoked wheel which is retractable into a compact volume by virtue of hinged rim and reelable spokes that is an efficient and stable structure for storing, deploying and supporting surfaces such as radar and communications antennas, shielding, earth sensing, solar cell arrays and solar energy reflectors.