Abstract: A satellite-based communications system operating at high data rates includes a plurality of satellites each having uplink and downlink antennas for transmitting and receiving a plurality of signal utilizing a plurality of spot beams to and from a plurality of coverage areas at a predetermined range of frequencies. The system also includes a plurality of user terminals for transmitting and receiving signals to and from the plurality of communications satellites at the predetermined range of frequencies and at one of the first plurality of data rates. Each of the user terminals having a steerable antenna for tracking relative movement of each of the user terminals with respect to each of the plurality of communications satellites are for tracking movement of each of the plurality of communications satellites in order to maintain communications with the plurality of communications satellite.

Abstract: An energy storage cell includes a vessel having a wall with a pair of oppositely disposed apertures therethrough, and an electrochemical cell, such as a nickel-hydrogen cell, within the vessel interior. A central core extends through the oppositely disposed apertures and performs all basic electrical, compressive support, and thermal removal functions for the energy storage cell. The central core includes electrical interconnects for the plate sets of the electrochemical cell, axial compression loading supports for the plate sets, and a heat pipe or other structure for removing heat from the interior of the vessel.

Abstract: A black film useful in thermal control has a matrix with 100 parts by weight of a polymer, and from about 1 to about 6 parts by weight of an electrically conductive carbon pigment having a porous, sponge-like structure dispersed through the matrix. The film may be a freestanding film, typically about 0.001 to about 0.003 inches thick, used as a radome. The film may instead be a liquid paint or a solid paint applied to a surface.

Abstract: A method for steering the payload beam of a satellite in a non-geostationary orbit toward an intended service area having known geographical dimensions in order to obtain improved pointing performance with a corresponding reduction in the demand on onboard hardware and software systems. The method comprises the steps of determining a subterranean target point and a direction fixed in the payload beam, calculating the orientation that points the payload beam direction through the subterranean target point, and maintaining this payload beam orientation using an on-board attitude control system.

Abstract: A dual-linearly polarized multi-mode rectangular horn includes a step junction in each of the two orthogonal planes for producing a desired amount of the higher order TE.sub.30 mode signal along with the dominant order TE.sub.10 mode signal for both of the vertical and horizontal polarization signals. The rectangular horn further includes a phasing section in each of the two orthogonal planes for causing the TE.sub.30 mode signal to be a desired amount of degrees out of phase with the TE.sub.10 mode signal at the aperture plane of the rectangular horn for both of the vertical and horizontal polarization signals. The rectangular horn is for use in a reconfigurable satellite array antenna.

Abstract: An apparatus and method for synchronizing a derived bit clock with a transmit bit clock of a transmitted data signal is disclosed. The present invention uses a divide-only direct digital synthesizer and a fixed local oscillator. The synthesizer generates a derived bit clock by dividing the fixed, high frequency local oscillator. A transition detector identifies valid bit transitions in the unsynchronized data signal. At each valid transition, a control algorithm determines whether to adjust the frequency and/or phase of the derived data clock in order to maintain synchronization between the derived bit clock and the transmit bit clock. The unsynchronized data signal and the derived bit clock are processed by a reclock latch to generate a synchronized data signal.