Abstract: Estimation of a desired antenna tracking profile is provided for a radio frequency autotracked (RFAT) antenna in the absence of a ground reference. A first RFAT antenna subsystem has a first antenna and a first antenna positioning mechanism (APM), each mounted on a vehicle, and a first ground-based RF beacon; a second RFAT antenna subsystem has a second antenna and a second APM, each mounted on the vehicle, and a second ground-based RF beacon. A controller stores an accumulated record of actuations of the second APM as a function of time under normal operation, calculates a desired antenna tracking profile for the second antenna, from a first ground-based RF beacon and from the accumulated record, excluding any real-time data from the second ground-based RF beacon, and transmits actuation commands to the second APM so as to cause the second antenna to track the desired antenna tracking profile.

Abstract: Three-axis spacecraft momentum management is performed for a spacecraft traveling along a trajectory, by an actuator including at least one thruster disposed on a single positioning mechanism. As the spacecraft travels along the trajectory, a desired line of thrust undergoes a substantial rotation in inertial space. When the spacecraft is located at a first location on the trajectory, the single positioning mechanism orients the thruster so as to produce a first torque to manage stored momentum in at least one of a first and a second of the three inertial spacecraft axes. When the spacecraft is located at a second location on the trajectory, the single positioning mechanism orients the thruster so as to produce a second torque to manage stored momentum in at least a third of the three inertial spacecraft axes.

Abstract: A broadband satellite having a payload subsystem configured to provide dual frequency conversion and bandwidth aggregation is communicatively coupled (i) to at least one gateway by a feeder link operating at a first frequency band; and (ii) to a plurality of user terminals by user links operating at a second frequency band. The payload subsystem has a first and a second frequency converter a satellite feeder link antenna feed, and a satellite user link antenna feed. The first frequency converter down converts, to a third frequency band, as an aggregated block, signals received at the satellite feeder link antenna feed from the gateway via the feeder link. The third frequency band is substantially lower than both the first and second frequency band. The down converted signals are routed to the second frequency converter for up converting to the second frequency band for transmission over the user link to the user terminals.

Abstract: Methods that test multibeam satellite communication systems, including its antennas and transponders. The methods use input power telemetry and output noise power to test satellite transponders and antennas while the satellite is in orbit. One method that tests a satellite receive antenna employs at least two earth stations, one for RF testing and one for telemetry and commanding, with each providing a backup for the other. Other methods may use one or more earth stations to perform testing. Methods are disclosed that generate receive antenna pattern measurements, transmit pattern measurements, input chain frequency response curves, input chain transfer curves, and output chain frequency response curves.

Abstract: A high capacity broadband service is provided from an Earth orbiting satellite having a payload that includes multiple large antennas, the satellite having an inverted configuration when deployed on orbit. The satellite has an aft surface proximate to a launch vehicle structural interface, a forward surface opposite to said aft surface, and a structure disposed therebetween. In a launch configuration, two or more deployable antennas are disposed, undeployed, on or proximate to and forward of the forward surface; on-orbit, the payload is operable when the satellite is disposed with the aft surface substantially Earth facing while the forward surface is substantially facing in an anti-Earth direction. Each deployable antenna is disposed, so as to be Earth facing, when deployed, in a position substantially forward and outboard of the forward surface.

Abstract: High data rata communications services are provided via a satellite system. Data is received from a user at a data rate greater than 30 Mbps over a communications link between the user and a first satellite, where the first satellite is one of a number of satellites within the satellite system; the data is forwarded over a crosslink from the first satellite to at least a second satellite within the satellite system; and the data is forwarded from the second satellite by a feeder link to a gateway located on the earth, said gateway being communicatively coupled to a terrestrial data network. The data is received from the user terminal by an antenna on the first satellite adapted for operation at a frequency associated with the feeder link.

Abstract: A redundant release apparatus having a multi-segment split spool with a central bore adapted to axially restrain a tensioned member. Two tensioned tapes are overlappingly wound around the spool segments thereby preventing radial movement of the spool segments. Overlapping winding design of each of the tapes provide predictable unwinding dynamics upon release. The multiple segments require less radial motion for release of the tensioned member.

Abstract: Methods and apparatus for a spacecraft (1) orbiting about a celestial body such as the Earth to reacquire operational three-axis orientation with respect to that body.

Abstract: A communications network (100) for maximizing bandwidth utilization. An embodiment of the invention comprises a spacecraft (11), at least one gateway (12) communicatively coupled to the spacecraft (11) by a feeder link (13) operating within at least one selected frequency band within a bandwidth, at least one user terminal (16) communicatively coupled to the spacecraft (11) by a user link (17), the user link (17) operable at any frequency band within the bandwidth without regard to polarization; and, the communications network (100) adapted to provide for simultaneous operation of at least a portion of the feeder link (13) and a portion of the user link (17) at a common polarization and frequency band within the bandwidth.

Abstract: Methods, systems and apparatus for ground-based beamforming of a satellite communications payload (200) within a satellite communications network (100). An embodiment of the invention comprises a satellite (11) communicatively coupled to at least one gateway (12) via a feeder link (13) and a plurality of user terminals (16), each communicatively coupled with the satellite by a user link (17) where a ground based beam forming system (400) receives, via feeder link (13), return path signals (452) traveling from the user terminals (16) via the satellite (11) to the at least one gateway (12) and forward path signals (457) traveling from the at least one gateway (12) via the satellite (11) to the user terminals (16), and measures and corrects amplitude and phase errors of the return path signals (452) and the forward path signals (457).

Abstract: Methods, systems and apparatus for ground-based beamforming of a satellite communications payload (200) within a satellite communications network (100). An embodiment of the invention comprises a satellite (11) communicatively coupled to at least one gateway (12) via a feeder link (13) and further coupled to a plurality of user terminals (16), each communicatively coupled with the satellite by a user link (17). A ground based beam forming system (400) measures and corrects amplitude and phase errors of a plurality of return path signals (452) traveling from the user terminals (16) via the satellite (11) to the at least one gateway (12), and measures and corrects amplitude and phase errors of a plurality of forward path signals (457) traveling from the at least one gateway (12) via the satellite (11) to the user terminals (16).

Abstract: An antenna system for producing selectively reconfigurable antenna beam coverage patterns suitable for use in on an earth orbiting spacecraft is described. The system comprises a main reflector and a feed element with a subreflector module on which are disposed one or more subreflectors. The subreflector module is selectably positionable such that any one of the subreflectors may be disposed such that it is illuminated by the feed element and illuminates the main reflector. Each of the subreflectors has a shaped surface corresponding to a desired antenna beam coverage beam pattern. By appropriate selection from among the plurality of subreflectors, any one of a plurality of antenna beam coverage patterns can by provided with a single feed element and single main reflector.

Abstract: A communication system having gateway filter and switching networks in forward and return channels of a frequency reuse communication satellite. The system couples subscriber terminals to the Internet or other terrestrial network by way of one or more gateways. The system cross-straps gateway-to-user beam connectivity provided by the communication satellite to allow full coverage of all user beams with a subset of the gateways having reduced frequency reuse. An exemplary system comprises a communication satellite having a return channel and a forward channel. One or more gateways are coupled to the Internet or other terrestrial network and communicate with subscriber terminals by way of the return and forward channels provided by the satellite. The return and forward channels each comprise a filter and switching network that selectively couple signals between the one or more gateways and the subscriber terminals.

Abstract: Heat dissipating apparatus or system for dissipating heat generated by a payload on a spacecraft having a plurality of surfaces. The system includes at least one radiator-condenser coupled to one or more of the surfaces of the spacecraft and a heat pump including an evaporator, a compressor, and an expansion valve coupled in a closed-loop manner to the radiator-condenser. The system components are coupled together using small diameter, thin- and smooth-walled tubing. The system enables the radiator-condenser to be elevated above the source or payload temperature, and, along with the use of thin walled tubing, reduces the mass of the spacecraft. Because the radiator-condenser temperatures are elevated, multiple surfaces of the spacecraft (west, east, earth and aft) can be effectively used as radiating surfaces.

Abstract: Broadband data transmission systems and methods that provide point-to-multipoint broadcasting capability to implement Internet access and multimedia distribution services for a very large number of users. An exemplary system comprises a two-way communication link having at least one satellite, at least one user terminal that has two-way communication with the two-way communication link, and at least one gateway that has access to data and has two-way communication with the two-way communication link. The two-way communication link may comprise a low bandwidth two-way communication link, or a low bandwidth request link and high bandwidth data broadcast link. The high bandwidth link preferably broadcasts a wide area coverage beam to allows the requested information to be received by many terminals. The terminal and gateway may each include a cache. Software at the gateway operates to deliver requested data and related data to users using the user's request history and/or user profile.

Abstract: A spacecraft, along with a spacecraft radiator system and spacecraft heat dissipation method are disclosed. The spacecraft comprises a body, a plurality of solar arrays, and the spacecraft radiator system. The spacecraft radiator system comprises first and second opposite facing payload radiators, first and second opposite facing deployable radiators, and one or more coupling or loop heat pipes cross coupling opposite facing payload and deployable radiators so that they function in tandem. By cross-coupling the opposite facing payload and deployable radiators, one of the two radiators acting in tandem is always in the shade during solstice seasons. Consequently, the solar load processed by the radiator system is minimized, thereby, increasing the thermal dissipation capability of the radiator system by approximately 15%.

Abstract: Heat dissipating apparatus for use in dissipating heat produced by electronic components of a spacecraft. The heat dissipating apparatus comprises first and second radiator panels each having an outer panel faceskin 18 and inner panel faceskin. A heat pipe matrix is disposed between outer and inner panel faceskins of each radiator panel, and a honeycomb core is disposed between the inner and outer panel faceskins that surrounds the heat pipe matrix. A transverse panel interconnects the first and second radiator panels. A plurality of crossing heat pipes extend between and thermally couple to the heat pipe matrices of the first and second radiator panels. The plurality of crossing heat pipes extend outside the plane of the transverse panel.

Abstract: A satellite command system and method that provides satellite commanding using remotely-controlled modulation of telemetry parameters on-board a satellite. Software is provided on each of the redundant processor units that creates separate DMA command input pathways to the redundant processor units. A command translator is used at a ground station to translate a command that is to be implemented on the satellite into a form ready for modulation. The command information is uplinked to the satellite by remotely manipulating (modulating) a quantity that can be measured by the on-board computer using its telemetry collection functions. The software implemented in processor units recognizes the modulation and processes it to reconstruct the command. The reconstructed command is passed to the processor unit, which then executes the command.

Abstract: Communications apparatus, such as a multibeam satellite communications system on-board a satellite, or terrestrial communications system, and methods that use a data routing technique that is based on the assignment of one or more codes corresponding to a destination beam. In particular, data routing is performed based on a CDMA code. The communications apparatus and methods allow simplified processing of the data address and routing of the data.

Abstract: A thermal distortion estimation system for delivering thermal time varying distortion of various spacecraft antenna is provided which includes a measurement signal outage indicator and a storage device containing time varying distortion data. A signal is generated indicating an outage for the system received by the spacecraft and then a generated time varying distortion of the system from a previous measurement history to predict the error resulting from the thermal distortion is employed to estimate the error.