Abstract: Beamforming channels of a satellite are calibrated using a low power, spread spectrum calibration signal. The power of the calibration signal is below the noise level of a user signal in an active channel, allowing channels to be calibrated while active. When calibrating the transmit side circuitry, a two-stage calibration can be used, first calibrating the output hybrid matrix, then calibrating the whole of the transmit side. To improve performance, the dwell time spend calibrating a channel can be based on the power of the user signal in the channel. A transmit probe can be used to inject a calibration signal into the receive antennae and a receive probe can be used to extract the calibration signal from the transmit antennae. To reduce frequency of calibrations, the calibrations can be based on path-to-path differences.

Abstract: A satellite communication system includes a satellite configured to provide a first plurality of spot beams adapted for communication with subscriber terminals using time domain beam hopping and a second plurality of spot beams adapted for communication with gateways. The satellite includes a spectrum routing network that is configured to time multiplex spot beams of the second plurality of spot beams with spot beams of the first plurality of spot beams so that a spot beam that is implementing beam hopping for communication to subscriber terminals communicates with different feeder beams (and, therefore, different gateways) at different times during a hopping period.

Abstract: A spacecraft propulsion system includes at least one chemical thruster operable with a liquid propellant, at least one electric thruster operable with an inert gas, and a first quantity ‘n’ of pressurant tanks, each of the ‘n’ pressurant tanks having a substantially identical volume. The propulsion system results from assembling a plurality of subassemblies, such that a first selectable number ‘e’ of the first quantity of pressurant tanks are manifolded together with the at least one electric thruster, and a second selectable number ‘c’ of the first quantity of pressurant tanks are manifolded together with the at least one chemical thruster. The first selectable number ‘e’ is an integer in the inclusive range of 1 to ‘n’, and c=n?e.

Abstract: An incremental deployment device is provided. The incremental deployment device may include a first member with a slotted track having alternating deployment and braking segments, as well as a second member that is movably coupled with the first member and that includes a cam follower that is configured to travel within the slotted track. The deployment segments may be configured to allow relative movement between the first member and the second member with little resistance, whereas the braking segments may be configured to permit relative movement between the first member and the second member with much greater resistance or to not permit any relative movement between the first member and the second member at all. Thus, the first member and the second member may be allowed to accelerate relative to one another within the deployment segments, and are decelerated within the braking segments.

Abstract: An example of a configurable channelizer includes N input ports and K output ports, each supporting M separately sampled subchannels; and one or more control circuits configured to store and apply a set of first routing tables to route subchannels in groups of R subchannels, each first routing table has M*K/R entries that link M*K/R groups of subchannels with the input ports, where R is an integer that is greater than or equal to 1.

Abstract: A constellation of Earth-orbiting spacecraft includes a first spacecraft disposed in a first orbit, a second spacecraft disposed in a second orbit, and a third spacecraft disposed in a third orbit. Each of the first orbit, the second orbit and the third orbit is substantially circular with a radius of approximately 42,164 km, and has a specified inclination with respect to the equator within a range of 5° to 20°. The first orbit has a first right ascension of ascending node RAAN1, the second orbit has a second RAAN (RAAN2) approximately equal to RAAN1+120°, and the third orbit has a third RAAN (RAAN3) approximately equal to RAAN1+240°. A fourth spacecraft is disposed in a fourth orbit that has a period of approximately one sidereal day, an inclination of less than 2°, a perigee altitude of at least 8000 km, and an eccentricity between approximately 0.4 and 0.66.

Abstract: A lattice structure includes a plurality of strut elements, each strut element formed by coupling one or more lengths of uncured graphite fiber reinforced polymer (GFRP) tow or yarn with posts so as to form a lattice, then curing the lattice. The lattice may include a plurality of open tetrahedral-like truss arrangements, each open tetrahedral-like truss arrangement including six strut elements and four posts.

Abstract: A payload subsystem of a satellite includes a plurality of transmit antenna feeds, a plurality of frequency filters, and a power amplification arrangement including a plurality of power amplifiers. The power amplification arrangement has at least one multiport amplifier, the multiport amplifier including a plurality of output ports, each output port coupled with a respective one of the plurality of transmit antenna feeds by way of a respective one of the plurality of frequency filters.

Abstract: Described herein are ground based subsystems, and related methods, for use in transmitting an optical feeder uplink beam to a satellite that is configured to receive the optical feeder uplink beam and in dependence thereon produce and transmit a plurality of RF service downlink beams within a specified RF frequency range to service terminals. Certain embodiments are related to a resource allocator for inclusion in a ground based subsystem, and methods for use therewith. Beneficially, the resource allocator, and methods for use therewith, eliminate any need for a satellite to perform any bandwidth allocation for the plurality of service downlink beams produced and transmitted by the satellite, thereby eliminating any need for the satellite to include an on-board channelizer. Such a recourse allocator can include a plurality of channels each of which can include an encoder and modulator, a channel filter, and a frequency up-converter.

Abstract: Beamforming channels of a satellite are calibrated using a low power, spread spectrum calibration signal. The power of the calibration signal is below the noise level of a user signal in an active channel, allowing channels to be calibrated while active. When calibrating the transmit side circuitry, a two-stage calibration can be used, first calibrating the output hybrid matrix, then calibrating the whole of the transmit side. To improve performance, the dwell time spend calibrating a channel can be based on the power of the user signal in the channel. A transmit probe can be used to inject a calibration signal into the receive antennae and a receive probe can be used to extract the calibration signal from the transmit antennae. To reduce frequency of calibrations, the calibrations can be based on path-to-path differences. These techniques are also applied to multiport amplifiers (MPAs).

Abstract: Beamforming channels of a satellite are calibrated using a low power, spread spectrum calibration signal. The power of the calibration signal is below the noise level of a user signal in an active channel, allowing channels to be calibrated while active. When calibrating the transmit side circuitry, a two-stage calibration can be used, first calibrating the output hybrid matrix, then calibrating the whole of the transmit side. To improve performance, the dwell time spend calibrating a channel can be based on the power of the user signal in the channel. A transmit probe can be used to inject a calibration signal into the receive antennae and a receive probe can be used to extract the calibration signal from the transmit antennae. To reduce frequency of calibrations, the calibrations can be based on path-to-path differences.

Abstract: Beamforming channels of a satellite are calibrated using a low power, spread spectrum calibration signal. The power of the calibration signal is below the noise level of a user signal in an active channel, allowing channels to be calibrated while active. When calibrating the transmit side circuitry, a two-stage calibration can be used, first calibrating the output hybrid matrix, then calibrating the whole of the transmit side. To improve performance, the dwell time spend calibrating a channel can be based on the power of the user signal in the channel. A transmit probe can be used to inject a calibration signal into the receive antennae and a receive probe can be used to extract the calibration signal from the transmit antennae. To reduce frequency of calibrations, the calibrations can be based on path-to-path differences. These techniques are also applied to multiport amplifiers (MPAs).

Abstract: A spacecraft includes a payload subsystem including a plurality of transmit antenna feeds, a digital channelizer, and a power amplification arrangement including a plurality of power amplifiers. The power amplification arrangement has at least one input communicatively coupled with an output of the digital channelizer and at least one output communicatively coupled with at least one of the plurality of transmit antenna feeds. A processor is configured to control the digital channelizer, and to adjust a saturated output power of at least one power amplifier of the plurality of power amplifiers in the power amplification arrangement.

Abstract: A communication platform such as a spacecraft, airborne platform, or terrestrial line of site wireless platform is provided with adaptive digital beamforming. The satellite digitizes a full spectrum allocation for digital channelization. A channelization engine can determine a particular user or user group associated with an uplink signal. In this manner, the communication platform can apply different processing based on the user or group associated with a signal. For example, the communication platform receives uplink signals associated with a first user group and a second user group in one embodiment. The platform dynamically generates one or more spot beams for the first user group and the second group. The platform discriminates the uplink signals to apply frequency hopping for the downlink frequency channel assignments to the second user group while the downlink frequency channel assignments for the first user group remain fixed.

Abstract: An imaging array fed reflector for a spacecraft is included in a spacecraft payload subsystem. The payload subsystem includes a multi-beam antenna including a reflector, a plurality of amplifiers, and a plurality of radiating feed elements, the feed elements configured as a phased array, illuminating the reflector, operable at a frequency having a characteristic wavelength (?), and configured to produce, in a far field at the reflector, a set of contiguous abutting beams. The amplifiers are disposed proximate to the plurality of radiating feed elements. Each radiating feed element has a respective coupling with at least one respective amplifier of the plurality of amplifiers. Each radiating feed element, together with the at least one respective amplifier, is disposed in a closely packed triangular lattice such that separation between adjacent radiating feed elements is not greater than 1.5?.

Abstract: Disclosed herein is a system including analog receive paths and analog transmit paths and signal processing equipment onboard a satellite, and methods for use therewith. For each of a plurality of the analog receive paths, a calibration signal is injected therein below a noise floor thereof, while the path is actively used to receive and condition an RF signal, and the calibration signal is extracted from the analog receive path after the signal has traveled through at least a portion of the path. The extracted calibration signal is compared to the injected calibration signal to determine gain and phase deviations caused by the path. Gain and phase characteristics of the analog receive paths are adjusted to compensate for different gain and phase deviations being caused by different paths. Similar techniques are used to compensate for different gain and phase deviations being caused by different analog transmit paths.

Abstract: This disclosure provides systems, methods and apparatus for implementing an arrangement of electromechanical switches. In one aspect, the arrangement includes rings of electromechanical switches configured to provide access to communication processing channels and redundancy access rows of electromechanical switches configured to provide access to redundant communication processing channels.

Abstract: A satellite system that includes a gateway, a satellite, and a user terminal. The gateway determines a modulation scheme based on a function of uplink and downlink signal quality and a defined relationship between the downlink modulation to the uplink modulation. The satellite includes an input demodulator configured to apply an input modulation and coding (modcod) scheme; an output modulator configured to apply an output modcod scheme; and an output modcod scheme selector configured to select an output modcod scheme for the output modulator based on the input modcod scheme according a predetermined relationship between input modcod schemes and output modcod schemes. The user terminal providing the gateway a measure of downlink signal quality.

Abstract: A spacecraft includes a payload subsystem, the payload subsystem including a phased array of feed elements configured to illuminate an antenna reflector, a beam forming network (BFN) disposed proximate to the array of feed elements, and a plurality of power amplifiers disposed between the BFN and the array of feed elements. The BFN includes a plurality of variable amplitude and phase adjusting arrangements disposed between (i) m:1 power combiners that are communicatively coupled with the power amplifiers and (ii) at least one 1:n power splitter, where m is greater than 1, and n is greater than 2.

Abstract: A spacecraft with a linear extension boom, an antenna feed, and a rigid antenna reflector is provided. The rigid antenna reflector may be connected with one end of the linear extension boom, and the other end of the linear extension boom may be connected with the spacecraft main body. In a launch configuration of the spacecraft, the linear extension boom may be retracted into a stowed configuration, and in an on-orbit configuration of the spacecraft, the linear extension boom may be extended into a deployed configuration, thereby moving the rigid antenna reflector away from the yaw axis of the spacecraft and positioning the rigid antenna reflector such that the focal point of the rigid antenna reflector may be oriented to align on, and be collocated with, the antenna feed. The rigid antenna reflector may be connected with the linear extension boom by a positioning mechanism that provides for adjustment in the angular orientation of the rigid antenna reflector relative to the linear extension boom.