Space Systems/loral, LLC

Birgit Sauer

John Scott Higham

Keith J Reckdahl

A spacecraft orbit control system and method that provides orbit control of a spacecraft. The system comprises the spacecraft, one or more electric and/or chemical thrusters disposed on the spacecraft, and a control processor having control outputs coupled to the plurality of thrusters. An orbit control algorithm is implemented that determines the current orbit of the spacecraft, determines whether or not to perform stationkeeping, determines desired changes in certain orbit parameters if stationkeeping is to be performed, determines thruster firings that accomplish the desired orbit parameter changes, and fires the thrusters to perform spacecraft stationkeeping and provide spacecraft longitude control. The present invention may be used with any type of orbit determination procedure (such as GPS or ranging, with or without orbit propagation) and any type of stationkeeping algorithm that calculates thruster firings from desired orbit-parameter corrections.

Closed-loop spacecraft orbit control

An automated spacecraft orbit compensation system and method that maintains a spacecraft in a desired orbit. The spacecraft orbit compensation system and method is automated to minimize human intervention. The system includes apparatus for determining orbital errors (ranging data) and apparatus for determining the duration and orbital location of thruster firings to correct the orbit. Each of the apparatus are located at a ground station. The system and method generates ranging data indicative of the range of the spacecraft. The ranging data are processed to estimate the orbit of the spacecraft. The estimated orbit is used to compute a thruster burn plan for the following N days. The thruster burn plan is uploaded to the spacecraft. The above steps are repeated at regular intervals.

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Cupertino, CA, United States of America

Birgit Sauer