Abstract: Coherent combining apparatus and methods that do not require training to adapt combining weights. The approach employed in the present invention uses phase-lock loops to demodulate input signals. The phase-lock loops are coupled so that their outputs are phase coherent. The outputs of the phase-lock loops are summed to obtain a coherent combining of the input signals. Exemplary embodiments of the present invention comprise two or more phase-lock loops having signal inputs and I and Q data outputs. A combiner sums the I and Q data output by the two or more phase-lock loops. A common decision circuit feeds back the summed output of the combiner to the two or more phase-lock loops and generates phase coherent output signals.

Abstract: Systems and methods that employ a phase change material to provide thermal control of electric propulsion devices (thrusters). A spacecraft is configured to have an electric propulsion thruster. The electric propulsion thruster is surrounded with a phase change material. Suitable phase change materials include high-density polyethylene (HDPE), waxes, paraffin materials, and eutectic salts. The spacecraft is launched into orbit. The electric propulsion thruster is fired for a predetermined period of time. Heat generated by the electric propulsion thruster is absorbed and stored in the phase change material while the thruster is firing. The stored heat is dissipated into space after the thruster has stopped firing.

Abstract: A loop heat pipe cooling system for use on a spacecraft. The loop heat pipe cooling system has loop heat pipes routed from internally facing surfaces of one or more internally located equipment panels to externally located radiator panels. Heat is collected at evaporator ends of each loop heat pipe and transported to condenser ends of the respective loop heat pipe. The condenser ends of the loop heat pipes may either be embedded within the radiator panel or externally mounted and coupled to the radiator panel using a loop heat pipe condensing flange. Fixed conductance heat pipes may also be used in any or all of the internal panels and radiator panels in order to collect and distribute heat loads to and from the loop heat pipes.

Abstract: Systems and methods that may be used to determine the distance between an orbiting satellite and a ground station. A master clock divider circuit generates clock signals derived from a master clock. A transmit code generation circuit generates pseudo-random number codes and processes the pseudo-random number codes to produce a composite signal having positive and negative correlation peaks that is transmitted to the satellite as an analog signal. A digitizing circuit receives the analog signal transmitted from the satellite, and digitizes the analog signal. A frequency domain matched filter match filters the digitized analog signal to produce correlation peaks contained in the digitized analog signal.

Abstract: A waveguide slot array antenna system, for use with a communications system 30 disposed on a satellite. The waveguide slot array antenna system comprises a feed waveguide having an input port and multiple output ports, a waveguide slot array having a plurality of slots formed therein that is coupled to the feed waveguide, and a waveguide lens disposed adjacent to the waveguide slot array. The phase of each contributing radiating waveguide is controlled to achieve radiation pattern shaping. Inner dimensions of the rectangular waveguides are designed to provide a phase velocity inside each waveguide that results in the appropriate radiated phase at the output of the waveguides. The phase radiated by each rectangular waveguide is determined by design, and the radiation pattern that results from the combined contributions of the array can be shaped to produce a complex radiation contour.

Abstract: An equalizer that couples a dual-mode dielectric resonator to a planar transmission line, creating an all-pass network. Coupling is achieved using circular polarization of the electromagnetic field in the dielectric resonator. The all-pass, non-reciprocal network is realized by the use of circular polarized energy and an offset cross shaped, through transmission line.

Abstract: An bendable double-walled insulated drinking straw for use in drinking hot and cold liquids. The insulated drinking straw comprises an inner tubular member that is sealed to an outer tubular insulating member at a sealed section, and that is separated from the inner tubular member at other than the sealed section to provide an air space therebetween. A flexible joint is formed at the sealed section that allows a portion of the straw on one side of the joint to articulate with respect to a portion of the straw on the other side of the joint. The double-walled portion of the straw may be the drinking end of the straw, or the entire straw may be double-walled, except for the sealed section. In one embodiment, an air space is formed between the inner and outer members. In another embodiment, interconnections are formed between the inner and outer members, such as ribs and serpentine members. In other embodiments, insulating material is disposed between the inner and outer members.

Abstract: An insulated drinking straw and an insulating member for use in drinking hot and cold liquids, such as those consumed from a cup or other container. The insulated drinking straw comprises an inner tubular member and an insulating member disposed around a portion of the periphery of the inner tubular member. The insulating member may be used as a separate device. In one embodiment of the insulating member, the insulating member has an inner shaft, an outer shaft connected to the inner shaft such that an air space is formed between the shafts, and a slot is formed in the insulating member between the inner and outer shafts. In another embodiment of the insulating member, the insulating member has an outer shaft, a compressible insulating material having an inner opening that is attached to an inner wall of the outer shaft, and a slot is formed in the compressible insulating material and outer shaft.

Abstract: An electric rocker switch is disclosed having a gull wing shaped rocking contact. The rocking contact pivots on a center terminal between a pair of upright blades. A centering protrusion disposed on a lower surface of the rocking contact rests between the uprights blades of the center terminal when the rocking contact is in a center position, thus preventing lateral movement of the rocking contact beyond the limits of the upright blades. First and second rocker contacts are located on opposite sides of the rocking contact. The first and second rocker contacts face toward first and second fixed contacts, respectively. Thus, the first rocker contact touches the first fixed contact when the rocking contact rocks to one side and the second rocker contact touches the second fixed contact when the rocking contact rocks to the other side. Positioning surfaces and top inside edges of the upright blades serve as pivots for the rocking contact as it rocks from side to side.

Abstract: Systems and methods that limit the effects of actuator saturation to certain body axes of a spacecraft. A plurality of actuators, or momentum wheels, disposed on the spacecraft are oriented non-parallel to x, y, and z axes of the spacecraft. The plurality of actuators each produce torque that is applied to the spacecraft. Outputs of the plurality of actuators or momentum wheels are processed to control the respective actuators or momentum wheels to manage actuator saturation so that saturation does not produce attitude errors about one or more predetermined axes of the spacecraft.

Abstract: An easily implementable satellite constellation stationkeeping algorithm for maintaining the relative positioning among satellites of a low earth orbit constellation with minimal maneuvering while maintaining the constellation altitude over the effects of atmospheric drag. The satellite constellation stationkeeping algorithm may be implemented as a system or method that uses atmospheric drag perturbations to extend the stationkeeping cycle of the satellites in the low earth orbit constellation while simplifying the implementation algorithm and performing minimal maneuvers. In an exemplary satellite constellation stationkeeping algorithm, a plurality of satellites or a ground station are configured with a controller that implements an absolute altitude control algorithm. The plurality of satellites are launched into a respective plurality of slots of a low earth orbit.

Abstract: Compact disk labeling systems for use in applying a compact disk label to a compact disk. One embodiment includes a compact disk case with a base and a rotatable lid that rotates about a hinge. A central spindle protrudes from a surface of the base that holds the compact disk by means of its central hole. A label hub protrudes from a surface of the lid. A flexible foam disk may be attached to an interior surface of the lid that is disposed around the label hub. Another embodiment includes a base having a generally flat upper surface. A central spindle protrudes slightly above the upper surface of the base that holds the compact disk by means of its central hole. A rotatable lid is attached to the base by means of a hinge and has a generally flat surface 23 with an inner tab section and an outer section that flex relative to each other. A cylindrically-shaped compact disk label hub protrudes from the inner tab section to hold the adhesive label.

Abstract: Apparatus and methods for pointing a non-deployable or deployable appendage disposed on a spacecraft. The appendage is secured to a backup structure comprising a plurality of beams. A plurality of control beams are secured to the backup structure. A plurality of deformation control elements, such as piezoelectric elements, for example, are secured to selected surfaces of the plurality of control beams. The deformation control elements are connected to a control source, such as a voltage control source, for example. Selected deformation control elements are activated to deform the associated control beams to point the deployable appendage in a desired direction.

Abstract: An antenna system and improved antenna support structure that is preferably used on a spacecraft. An exemplary antenna system comprises an antenna dish, an antenna positioning mechanism, and the present antenna support structure coupled between the antenna dish and antenna positioning mechanism. The antenna support structure comprises a composite ring attached to a rear surface of the antenna dish and a boom structure coupled to the composite ring and to the antenna positioning mechanism that comprises a plurality of tubular fingers that interconnect the composite ring and the antenna positioning mechanism. The boom structure may further comprise one or more lateral supports that interconnect the plurality of tubular fingers. The composite ring is preferably disposed in a plane containing the center of gravity of the antenna dish. The composite ring, tubular fingers, and lateral supports preferably comprise graphite fibers.

Abstract: An antenna deployment system for use in storing and deploying three antennas that are located on the same side of a spacecraft or other fixed body. The three antennas are nested and are stacked in a stowed condition and are individually and sequentially deployed to their respective deployed positions. One or more feed horns are attached to the spacecraft or fixed body that illuminate the respective antennas. A dual axis deployment mechanism is used to deploy each antenna. The dual axis deployment mechanism is also used to steer the beam produced by the antenna. The dual axis deployment mechanism comprises a dual-axis rotatable hinge structure affixed to the spacecraft or fixed body that is coupled to the antenna by way of a substantially rigid reflector support structure. The dual axis deployment mechanism is actuated and controlled to deploy the antenna and steer the antenna beam.

Abstract: A controller and control method that perform satellite orbit-keeping maneuvers and proportionally scale orbit-keeping pulses to automatically minimize disturbance torques on-board a satellite. The controller and control method may also be used to remove residual momentum stored in spinning momentum wheels.

Abstract: A spacecraft orbit control system and method that provides orbit control of a spacecraft. The system comprises the spacecraft, one or more electric and/or chemical thrusters disposed on the spacecraft, and a control processor having control outputs coupled to the plurality of thrusters. An orbit control algorithm is implemented that determines the current orbit of the spacecraft, determines whether or not to perform stationkeeping, determines desired changes in certain orbit parameters if stationkeeping is to be performed, determines thruster firings that accomplish the desired orbit parameter changes, and fires the thrusters to perform spacecraft stationkeeping and provide spacecraft longitude control. The present invention may be used with any type of orbit determination procedure (such as GPS or ranging, with or without orbit propagation) and any type of stationkeeping algorithm that calculates thruster firings from desired orbit-parameter corrections.

Abstract: A satellite-based antenna system that employs an improved dual function subreflector. An exemplary antenna system comprises a flat plate dual function subreflector and a subreflector positioning mechanism that selectively positions the subreflector at predetermined positions corresponding to two or more operational positions of the satellite. A plurality of feed arrays couple energy to and from the subreflector, and a main reflector generates beams for desired coverage areas. The present invention provides optimum performance from a dual reflector antenna when operating in two or more different satellite positions, with no compromise to the performance for either mode of operation.

Abstract: Compact disk labeling systems for use in applying an adhesive label to a CD card compact disk. The system includes a base with a generally flat upper surface and a compact disk hub that protrudes above the upper surface of the base for holding the CD card compact disk by means of its central hole. A rotatable lid is attached to the base and has a generally flat surface with an tab section and a flexible section that is flexible relative to the tab section. A compact disk label hub protrudes from the tab section that is used to hold the adhesive label. A compact disk registering member is provided on the base that is used to register and align the CD card compact disk. A compact disk label registering member may be provided on the lid that may be used to register labels having different widths. Removal of the compact disk registering member permits labeling of mini round compact disks.

Abstract: An automatic network analyzer that measures continuous wave radio microwave driven transfer characteristics of nonlinear devices and simultaneously calculates and displays corresponding noise driven transfer characteristics and noise power ratio data. This automatic network analyzer employs software or firmware that uses closed-form equations to exactly calculate noise parameters. This is done in real-time as CW measurements are taken.