Abstract: A hybrid communications assembly for a spacecraft is provided. The hybrid communications assembly may include an assembly base, one or more laser communications terminals mounted on the assembly base, and a radio frequency antenna system mounted on the assembly base. The assembly may be mounted on an earth deck of the spacecraft, and the laser communications terminals may be mounted at an angle between 20 and 70 degrees with respect to the earth deck. A thermal radiator may be mounted on the assembly base and thermally coupled to the laser communications terminal. The radio frequency antenna system may be disposed between the laser communications terminals. The radio frequency antenna system may include one or more antenna reflectors mounted on the assembly base and one or more antenna feeds mounted on a tower.

Abstract: According to some aspects of the subject disclosure, a spacecraft comprises first and second pluralities of thrusters. The pluralities of thrusters are attached to a spacecraft body by booms configured to move the first plurality of thrusters between stowed and deployed positions. The deployed position of the first plurality of thrusters is farther north than is the stowed position of the first plurality of thrusters. The deployed position of the second plurality of thrusters is farther south than is the stowed position of the second plurality of thrusters. The first plurality of thrusters comprises a first thruster and a second thruster separated from each other in an east-west direction. The second plurality of thrusters comprises a third thruster and a fourth thruster separated from each other in the east-west direction.

Abstract: According to some aspects of the subject disclosure, a spacecraft comprises first and second pluralities of thrusters. The pluralities of thrusters are attached to a spacecraft body by booms configured to move the first plurality of thrusters between stowed and deployed positions. The deployed position of the first plurality of thrusters is farther north than is the stowed position of the first plurality of thrusters. The deployed position of the second plurality of thrusters is farther south than is the stowed position of the second plurality of thrusters. The first plurality of thrusters comprises a first thruster and a second thruster separated from each other in an east-west direction. The second plurality of thrusters comprises a third thruster and a fourth thruster separated from each other in the east-west direction.

Abstract: A side-by-side dual-launch spacecraft arrangement is provided. The arrangement may include a dual-launch adaptor, a first spacecraft, and a second spacecraft. The first spacecraft and the second spacecraft may be mounted on the dual-launch adaptor and may be arranged side by side on the dual-launch adaptor. An aspect ratio of each of the first and second spacecraft may be within a range of 0.55 and 0.8.

Abstract: A hybrid communications assembly for a spacecraft is provided. The hybrid communications assembly may include an assembly base, one or more laser communications terminals mounted on the assembly base, and a radio frequency antenna system mounted on the assembly base. The assembly may be mounted on an earth deck of the spacecraft, and the laser communications terminals may be mounted at an angle between 20 and 70 degrees with respect to the earth deck. A thermal radiator may be mounted on the assembly base and thermally coupled to the laser communications terminal. The radio frequency antenna system may be disposed between the laser communications terminals. The radio frequency antenna system may include one or more antenna reflectors mounted on the assembly base and one or more antenna feeds mounted on a tower.

Abstract: A side-by-side dual-launch spacecraft arrangement is provided. The arrangement may include a first and second spacecraft mounted within a fairing. The first and second spacecraft may be mounted side by side on the dual-launch adaptor. A ratio of a first lateral dimension of the GEO spacecraft to a second lateral dimension of the GEO spacecraft may be within a range from 0.55 to 0.8, with the first lateral dimension and the second lateral dimension being perpendicular to each other and smaller than a height of the GEO spacecraft.

Abstract: Embodiments of the present invention provide an ion-thruster stationkeeping method and mounting configuration that reduces the propellant penalty when a single thruster fails, e.g., in the case where only three of a spacecraft's four ion thrusters are available. By improving firing efficiency for the single-thruster failure case, on-board propellant is reduced, thereby allowing increased payload mass. Also, the configuration supports both N/S and E/W stationkeeping using four ion thrusters (or three thrusters for the failure case) and therefore does not require a separate propulsion system or thrusters for E/W stationkeeping.

Abstract: The present invention addresses performance limitation of gyros (e.g., MEMS gyros) by significantly reducing common-mode noise and bias effects. In one embodiment, an array of gyros, which may comprise four or more gyros, is configured so that common-mode error effects can be separated from the sensed rotational motion of the gyros and therefore removed. Removing the common-mode effects increases attitude estimation and spacecraft pointing accuracy, particularly during periods when the gyros must solely provide the attitude reference.

Abstract: Embodiments of the present invention provide an ion-thruster stationkeeping method and mounting configuration that reduces the propellant penalty when a single thruster fails, e.g., in the case where only three of a spacecraft's four ion thrusters are available. By improving firing efficiency for the single-thruster failure case, on-board propellant is reduced, thereby allowing increased payload mass. Also, the configuration supports both N/S and E/W stationkeeping using four ion thrusters (or three thrusters for the failure case) and therefore does not require a separate propulsion system or thrusters for E/W stationkeeping.

Abstract: A heat transfer assembly can include an equipment panel having an east end and a west end. East and west radiator panels are coupled to the east and west ends, respectively, of the equipment panel. The assembly also includes a plurality of flexible heat pipes each having a first rigid tube thermally coupled to the east radiator panel, a second rigid tube coupled to the equipment panel, a third rigid tube thermally coupled to the west radiator panel, a first flexible tube sealingly coupled between the first and second rigid tubes, and a second flexible tube sealingly coupled between the second and third rigid tubes. The equipment panel is configured to retain one or more equipment modules in thermal contact with the second rigid tube of at least one of the plurality of flexible heat pipes.

Abstract: A geostationary earth orbit (GEO) spacecraft is disclosed that includes a body with north, east, south, and west sides and a north-south axis. The spacecraft has at least one deployable radiator rotatably coupled to the body. The deployable radiator has a stowed position proximate to one of the east and west sides and a deployed position that is greater than 90 degrees from the north-south axis in a direction away from the respective one of the east and west sides.

Abstract: A side-by-side dual-launch spacecraft arrangement is provided. The arrangement may include a dual-launch adaptor, a first spacecraft, and a second spacecraft. The first spacecraft and the second spacecraft may be mounted on the dual-launch adaptor and may be arranged side by side on the dual-launch adaptor. An aspect ratio of each of the first and second spacecraft may be within a range of 0.55 and 0.8.

Abstract: A deployable radiator arrangement for cooling a geostationary earth orbit spacecraft is provided. In some aspects, the geostationary earth orbit spacecraft may comprise first and second deployable radiators mounted on an east or west surface of the spacecraft when stowed. The first and second deployable radiators are configured to rotate into a north and south facing position, respectively, when deployed. The geostationary earth orbit spacecraft may further comprise first and second fixed radiators disposed on a north and south surface of the spacecraft, respectively. The first and second deployable radiators are thermally coupled to the first and second fixed radiators, respectively.

Abstract: The present disclosure provides systems and methods that improve the pointing accuracy of a spacecraft using temperature-sensitive gyros (e.g., MEMS gyros) by using a temperature bias model to compensate for temperature biases of the gyros and using attitude data (e.g., star tracker data) to automatically and continuously calibrate the temperature bias model over the life of the spacecraft. When star tracker data is unavailable (e.g., due to sun interference), the most recently updated temperature bias model is used in open-loop to provide improved estimation of the gyro biases and improved attitude estimation.

Abstract: A deployable radiator arrangement for cooling a geostationary earth orbit spacecraft is provided. In some aspects, the geostationary earth orbit spacecraft may comprise first and second deployable radiators mounted on an east or west surface of the spacecraft when stowed. The first and second deployable radiators are configured to rotate into a north and south facing position, respectively, when deployed. The geostationary earth orbit spacecraft may further comprise first and second fixed radiators disposed on a north and south surface of the spacecraft, respectively. The first and second deployable radiators are thermally coupled to the first and second fixed radiators, respectively.

Abstract: A system for isolating vibration among a plurality of instruments on a spacecraft includes at least two platforms, each of which is configured to couple to and isolate vibration for a single one of the plurality of instruments. Each of the at least two platforms is configured to mount to the spacecraft. A device is also provided for isolating vibration for one instrument among a plurality of instruments on a spacecraft.

Abstract: A method of providing attitude and antenna steering for a spacecraft having a number of reaction wheels and a number of antennas is disclosed. The method includes determining a beta angle, the beta angle being the angle between a sun vector and an orbit plane of the spacecraft, and engaging either a first mode or a second mode in an alternate manner to provide attitude and antenna steering based on the beta angle. A target frame generator for generating information usable to provide attitude and antenna steering for a spacecraft is also disclosed.

Abstract: A system for providing attitude control with respect to a spacecraft is provided. The system includes a reaction wheel control module configured to control a number of reaction wheel assemblies associated with the spacecraft in order to control attitude, and a maneuver control module configured to use a number of gimbaled Hall Current thrusters (HCTs) to control the total momentum associated with the spacecraft. The total momentum includes the momentum associated with the reaction wheel assemblies and the angular momentum of the spacecraft. Using the gimbaled HCTs to control the momentum associated with the reaction wheel assemblies results in minimal HCT gimbal stepping.

Abstract: A system for providing attitude control with respect to a spacecraft is provided. The system includes a reaction wheel control module configured to control a number of reaction wheel assemblies associated with the spacecraft in order to control attitude, and a maneuver control module configured to use a number of gimbaled Hall Current thrusters (HCTs) to control the total momentum associated with the spacecraft. The total momentum includes the momentum associated with the reaction wheel assemblies and the angular momentum of the spacecraft. Using the gimbaled HCTs to control the momentum associated with the reaction wheel assemblies results in minimal HCT gimbal stepping.

Abstract: A spacecraft includes a plurality of thrusters, a thruster firing logic, an actuator assembly, an attitude control system, and a torque calibration system. The plurality of thrusters is configured to apply torque to the spacecraft. The thruster firing logic is configured to control firing of the plurality of thrusters. The actuator assembly is configured to apply torque to the spacecraft. The attitude control system is configured to sense an attitude of the spacecraft and to provide an attitude control torque. The torque calibration system is configured to provide a thruster feedforward torque. A machine-readable medium includes instructions for a method for providing torque calibration to a spacecraft.