Space Systems/loral, LLC

John Hutton Cooper

Philip Conway Hirschberg

Mohammad Saghir Munir

Byoungsam Woo

Farid Ganji

Techniques for orienting an earth-orbiting spacecraft include determining, using a star tracker on board the spacecraft, a first vector aligned between an ecliptic pole of the earth and the spacecraft, adjusting attitude of the spacecraft so as to align a first axis of the spacecraft with the first vector, and rotating the spacecraft about the first axis until presence of the sun is registered. Rotation rates may be subsequently reduced, such that the sun remains within a field of view of the sun sensor or of a solar array of the spacecraft.

Ecliptic sun acquisition control mode for satellites

Spacecraft momentum management techniques are coordinated with station-keeping maneuvers or other delta-V maneuvers. A body stabilized spacecraft attitude is controlled, the spacecraft including at least one momentum/reaction wheel, and a set of thrusters. A first momentum storage deadband limit is adjusted, the adjustment being related to a first delta-V maneuver window. A momentum management strategy is executed with the adjusted first momentum storage deadband limit such that a first thruster firing that performs desaturation of the momentum/reaction wheel also provides velocity change beneficial to the first delta-V maneuver.

Spacecraft momentum unload and station-keeping techniques

Stored momentum on a spacecraft is managed by determining a target profile of stored momentum as a function of time for the spacecraft; measuring a difference between a momentum value actually stored on the spacecraft and a desired momentum value, where the desired momentum value substantially conforms to the target profile at a particular time; reducing the difference by producing a torque on the spacecraft, where the torque results from selectively controlling at least one solar array position offset angle, the offset angle being an offset of at least one solar array of the spacecraft from a nominal sun pointing direction.

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John Hutton Cooper