Abstract: A spacecraft includes a first deployable module and a second deployable module and is reconfigurable from a launch configuration to an on-orbit configuration. In the launch configuration, the first deployable module is adjacent to the second deployable module. The first deployable module includes a first solar array, the first solar array being rotatable, in the on-orbit configuration, about a first axis of rotation, and the second deployable module includes a second solar array, the second solar array being rotatable, in the on-orbit configuration, about a second axis of rotation, the second axis of rotation being separated by a substantial distance from the second axis of rotation.

Abstract: A spacecraft includes a payload subsystem including a digital channelizer. The digital channelizer provides at least a portion of spacecraft command or telemetry functionality. The spacecraft may optionally also include a telemetry and command (T&C) subsystem, the T&C subsystem including one or more of a command receiver, a command decoder, a telemetry encoder and a telemetry transmitter. The digital channelizer may be communicatively coupled with at least one of the command receiver, the command decoder, the telemetry transmitter and the telemetry encoder.

Abstract: A communication system uses resources (including a first signal path and a second signal path) in a first roundtrip direction for a first set of gateways and subscriber terminals while concurrently using the same resources (including the first signal path and the second signal path) in a second roundtrip direction for a second set of gateways and subscriber terminals.

Abstract: A spacecraft includes a payload subsystem including a digital channelizer. The digital channelizer provides at least a portion of spacecraft command or telemetry functionality. The spacecraft may optionally also include a telemetry and command (T&C) subsystem, the T&C subsystem including one or more of a command receiver, a command decoder, a telemetry encoder and a telemetry transmitter. The digital channelizer may be communicatively coupled with at least one of the command receiver, the command decoder, the telemetry transmitter and the telemetry encoder.

Abstract: A spacecraft includes a payload subsystem including a digital channelizer. The digital channelizer provides at least a portion of spacecraft command or telemetry functionality. The spacecraft may optionally also include a telemetry and command (T&C) subsystem, the T&C subsystem including one or more of a command receiver, a command decoder, a telemetry encoder and a telemetry transmitter. The digital channelizer may be communicatively coupled with at least one of the command receiver, the command decoder, the telemetry transmitter and the telemetry encoder.

Abstract: A communication system uses resources (including a first signal path and a second signal path) in a first roundtrip direction for a first set of gateways and subscriber terminals while concurrently using the same resources (including the first signal path and the second signal path) in a second roundtrip direction for a second set of gateways and subscriber terminals.

Abstract: A launch vehicle payload that includes at least two spacecraft is disclosed. The launch vehicle includes a single payload adapter. Each spacecraft has a launch vehicle adapter structure providing a respectively coplanar structural interface directly with the single launch vehicle payload adapter. The spacecraft share a launch vehicle payload fairing volume substantially side-by-side and are detachably coupled together such that a positive clearance is provided between adjacent, non-abutting structural body surfaces of each spacecraft.

Abstract: A launch vehicle payload that includes at least two spacecraft is disclosed. The launch vehicle includes a single payload adapter. Each spacecraft has a launch vehicle adapter structure providing a respectively coplanar structural interface directly with the single launch vehicle payload adapter. The spacecraft share a launch vehicle payload fairing volume substantially side-by-side and are detachably coupled together such that a positive clearance is provided between adjacent, non-abutting structural body surfaces of each spacecraft.

Abstract: A method for estimating motion of a dual-spin spacecraft having a gimballed momentum wheel. The method disengages the gimbal from its drive train in anticipation of a short disturbance. Then, the gimbal slip resulting from the disturbance is measured. The method may be used to stabilize any dual-spin spacecraft that uses a gimballed momentum wheel. To stabilize the dual-spin spacecraft, the gimbal angle and gimbal rate are measured during and after the disturbance to provide an indication of the inertial spacecraft motion along gimbal axes. The magnitude and direction of the disturbance are determined by comparing motion of the gimbal before and after the disturbance. Then, torques are applied to the gimbal to counteract the spacecraft motion resulting from the disturbance.

Abstract: A low cost, fuel efficient solution to the problem of avoiding high yaw errors in communications satellites after station keeping maneuvers is achieved by adding a selectable function to the LTMM controller which allows it to calculate roll momentum based on measured yaw attitude error data from the yaw DIRA. The so calculated roll momentum is used to trigger roll unloads, which will reduce the yaw attitude error. This solution has the advantages that: it maintains yaw attitude error within the pointing budget; the fuel penalty is negligible; it can be made fully automatic; it can be disabled and not used; and, it requires only a very small addition to the firmware.

Abstract: A system and method employ a sensing of the attitude or orientation of a spacecraft for correcting the orientation of a line of sight of an instrument carried by a spacecraft to compensate for a transient perturbation in the attitude of the spacecraft. The instrument may be a microwave antenna for communicating with a station on the earth, or a camera for viewing the earth. The transient perturbation in the orientation, such as may be caused by the firing of a thruster of the spacecraft, is extracted from a measurement of the spacecraft orientation, such as the orientation relative to the earth. The line of sight of the instrument is reoriented by injection of an incremental orientation equal and opposite to the transient perturbation. The application of the incremental orientation can be accomplished in mechanical fashion, in the case of an antenna mechanically mounted to the spacecraft, and electrically, as in the case of a phased array antenna carried by the spacecraft.