| CPC B64G 1/242 (2013.01) [B64G 1/244 (2019.05); B64G 1/646 (2013.01)] | 20 Claims |

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1. A controller for maintaining a spacecraft near an orbit, the controller comprising:
a memory configured to store executable instructions; and
a processor configured to execute the executable instructions to cause the controller to:
detect that a distance from the spacecraft to the orbit is greater than a spacecraft threshold;
in response to detecting that the distance from the spacecraft to the orbit is greater than the spacecraft threshold:
linearize dynamics of the spacecraft from a current time over a time horizon with respect to a high fidelity reference trajectory to produce a state transition matrix (STM) for an uncontrolled motion of the spacecraft within the time horizon, wherein the state transition matrix includes non-expanding eigenvectors with magnitudes less than or equal to one and expanding eigenvectors with magnitudes greater than one;
determine a control action that changes an upcoming state of the spacecraft to a linear combination of the non-expanding eigenvectors of the state transition matrix; and
generate a control command to an actuator of the spacecraft causing correction of the upcoming state of the spacecraft along a direction corresponding to at least one of the non-expanding eigenvectors of the state transition matrix.
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