Space Systems/loral, LLC

Reticle Labs LLC

Mohammad Saghir Munir

Walter S Gelon

Kam K Chan

Darren R Stratemeier

Philip Conway Hirschberg

John Hutton Cooper

Byoungsam Woo

Techniques for performing orbit raising, north-south stationkeeping, east-west stationkeeping, and momentum management with thrusters disposed on a spacecraft are disclosed. The spacecraft includes at least one thruster support mechanism (TSM), including a pointing arrangement and an elongated structural member, the structural member having a long dimension defining a first axis a proximal portion of the structural member is attached to the pointing arrangement each of the thrusters is fixedly coupled with a distal portion of the structural member. The pointing arrangement includes a first, second, and third revolute joint, the first revolute joint being rotatable about the first axis; the third revolute joint being rotatable about a third axis, the third axis being fixed with respect to the spacecraft; and the second revolute joint being rotatable about a second axis, the second axis being orthogonal to each of the first axis and the third axis.

Thruster support mechanism for satellite propulsion

This invention allows tracking of a defect across multiple inspections. The inventive solution translates every inspection record into a common set of fields that are first archived into a relational database. Then the defect coordinates from the inspection records of the same mask are all transformed into a common reference frame having the same origin and orientation with respect to the mask coordinate system. Following this, the defect having coordinates within a given tolerance distance are paired up and reported to the user.

Method for tracking defects on a photomask across repeated inspections

Three-axis spacecraft momentum management is performed for a spacecraft traveling along a trajectory, by an actuator including at least one thruster disposed on a single positioning mechanism. As the spacecraft travels along the trajectory, a desired line of thrust undergoes a substantial rotation in inertial space. When the spacecraft is located at a first location on the trajectory, the single positioning mechanism orients the thruster so as to produce a first torque to manage stored momentum in at least one of a first and a second of the three inertial spacecraft axes. When the spacecraft is located at a second location on the trajectory, the single positioning mechanism orients the thruster so as to produce a second torque to manage stored momentum in at least a third of the three inertial spacecraft axes.

Spacecraft momentum management

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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Union City, CA, United States of America

Mohammad Saghir Munir