An orbiting satellite can be maintained in a virtual orbit, having an orbital period equal to the natural orbit of a satellite at a different altitude, by equipping the satellite with at least one radial thruster. Radial thrusters on the anti-nadir-facing side of the satellite allow for virtual orbits higher than the natural altitude, while radial thrusters on the nadir-facing side of the satellite allow for virtual orbits lower than the natural altitude. This allows a satellite to evade threats, such as orbital debris and/or hostile spacecraft, without losing its relative position within a satellite constellation or experiencing the diminished services often attendant such maneuvers. Similar techniques can also be used for surveillance of orbiting satellites.

A stationkeeping strategy for a satellite disposed in a TAP orbit includes controlling parameters of the orbit such that, for a constellation of two satellites disposed in the orbit, the constellation provides substantially continuous coverage of a polar region. The stationkeeping strategy includes one or more of: establishing an initial Right Ascension of Ascending Node (RAAN) of the operational orbit such that naturally caused orbital drift results in a mid-life RAAN of approximately 0 degrees (360 degrees); and controlling Argument of Perigee (ARGP), only indirectly, by performing orbit maintenance maneuvers only to directly control one or more of the operational orbit apogee altitude, the operational orbit perigee altitude, and inclination within a respective required range.

A spacecraft including a set of thrusters for changing a pose of the spacecraft. At least two thrusters mounted on a gimbaled boom assembly and are coupled together sharing the same gimbal angle. A model predictive controller (MPC) to produce a solution for controlling thrusters of the spacecraft by optimizing a cost function over a receding horizon using a model of dynamics of the spacecraft effecting a pose of the spacecraft and a model of dynamics of momentum exchange devices of the spacecraft effecting an orientation of the spacecraft. A modulator to modulate magnitudes of the thrust of the coupled thrusters determined by the MPC as pulse signals specifying ON and OFF states of each of the coupled thruster, wherein the ON states of the coupled thrusters sharing the same gimbal angle do not intersect in time. A thruster controller to operate the thrusters according to their corresponding pulse signals.

A control system for controlling an operation of a spacecraft. A model predictive controller (MPC) produces a solution for controlling thrusters of the spacecraft. The MPC optimizes a cost function over a finite receding horizon using a model of dynamics of the spacecraft effecting a pose of the spacecraft and a model of dynamics of momentum exchange devices of the spacecraft effecting an orientation of the spacecraft. The optimization is subject to hard and soft constraints on angles of thrusts generated by thrusters. Further, the hard constraints require the angles of thrusts in the solution to fall within a predetermined range defined by the hard constraints. The soft constraints penalize the solution for deviation of the angles of thrusts from nominal angles corresponding to a torque-free thrust passing through the center of the mass of the spacecraft. A thruster controller operates the thrusters according to the solution of the MPC.

Spacecraft servicing systems include a spacecraft servicing device and at least one pod comprising at least one spacecraft servicing component. The spacecraft servicing device is configured to transfer the at least one pod to a target spacecraft in order to service the target spacecraft with the at least one spacecraft servicing component of the at least one pod. Spacecraft servicing pods configured to be supplied to a spacecraft with a spacecraft servicing device include at least one spacecraft servicing component.

Spacecraft servicing devices and related methods may include a propellant tank configured to store a propellant and to be placed into fluid communication with a portion of the target spacecraft.

Spacecraft servicing devices or pods and related methods may include a body configured to be deployed from a host spacecraft at a location adjacent a target spacecraft and at least one spacecraft servicing component configured to perform at least one servicing operation on the target spacecraft.

An operation of a spacecraft is controlled using an inner-loop control determining first control inputs for momentum exchange devices to control an orientation of the spacecraft and an outer-loop control determining second control inputs for thrusters of the spacecraft to concurrently control a pose of the spacecraft and a momentum stored by the momentum exchange devices of the spacecraft. The outer-loop control determines the second control inputs using a model of dynamics of the spacecraft including dynamics of the inner-loop control, such that the outer-loop control accounts for effects of actuation of the momentum exchange devices according to the first control inputs determined by the inner-loop control. The thrusters and the momentum exchange devices are controlled according to at least a portion of the first and the second control inputs.

An object is to notify an appropriate intrusion alert by determining whether debris will intrude into an orbit area of a satellite constellation. A passage determination unit (110) determines whether debris will pass through a satellite orbit area, based on satellite orbit forecast information in which a forecast value of an orbit of a satellite is set and debris orbit forecast information in which a forecast value of an orbit of debris is set. When it is determined that debris will pass through the satellite orbit area, an alert generation unit (120) generates an intrusion alert (111) including a predicted time, predicted location coordinates, and predicted velocity vector information that relate to passage of the debris. An alert notification unit (130) notifies the intrusion alert (111) to a management business device (40) used by a management business operator that manages a satellite that flies in the satellite orbit area.

To control a mobile node group that performs a formation flight, mobile nodes constituting the mobile node group and a ground station that wirelessly communicates with each of the mobile nodes are included. The mobile nodes are classified into a follower mobile node and a leader mobile node that collects information on the follower mobile node and controls the follower mobile node. The mobile nodes wirelessly communicate with one another based on beamforming or MIMO. Based on an installed on-board processor, the leader mobile node controls the follower mobile node, and the mobile node controls a position or an attitude of the mobile node itself for performing the formation flight. The ground station performs link control of the wireless communication with the mobile node or link control of the wireless communication between the mobile nodes, and control of selecting any ground station that wirelessly communicates with the mobile node.