Abstract: A Hall-effect thruster assembly includes a plurality of magnetic sources for creating a magnetic circuit. The plurality of magnetic sources are positioned between a first end and a second, opposite end of the Hall-effect thruster. The plurality of magnetic sources define a longitudinal axis extending through the first end and the second end. The first end is configured as a discharge end. A mount assembly is coupled to the second end. The mount assembly is configured to secure the plurality of magnetic sources to a spacecraft. A magnetic element is supported by the mount assembly. The magnetic element is positioned relative to the plurality of magnetic sources by the mount assembly.

Abstract: A thruster control device has an opening degree estimating section and an opening degree control section. The opening degree estimating section calculates an estimated opening degree of a valve showing a rate at which the valve is opened, based on a balance of an acting force applied to a valve element of the valve to adjust a quantity of combustion gas to be ejected from a thruster and a fluid force applied to the valve element by the ejected combustion gas. The opening degree control section determines a target opening degree based on the estimated opening degree to control the opening degree of the valve.

Abstract: 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.

Abstract: A small satellite propulsion system using a gaseous oxidizer and a gaseous fuel as primary propellants with a liquid as a film coolant for the inner surface of the rocket motor. The gaseous fuel is also used as a pressurant for the coolant and as a cold gas propellant for attitude control system (hereinafter “ACS”) thrusters. The oxidizer, fuel, and coolant tanks, as well as most valves and plumbing, are integrated into a single core unit along with the rocket motor, rocket motor plumbing, and safety valves. Attitude control thrusters may be remotely located with plumbing to the fuel tank. The core unit is four inches high and less than four inches deep and wide. The small satellite propulsion system uses no pyrotechnics and no hazardous toxic materials.

Abstract: A spacecraft including a spacecraft bus and a set of thrusters for changing a pose of the spacecraft. Wherein at least two thrusters are mounted on a gimbaled boom assembly connecting the two thrusters with the spacecraft bus, such that the two thrusters are coupled thrusters sharing the same gimbal angle. A model predictive controller to produce a solution for controlling thrusters of the spacecraft by optimizing a cost function over multiple receding horizons. The cost function is composed of a cost accumulated over the multiple receding horizons, including a cost accumulated over a first horizon using a dynamics governing a north-south position of the spacecraft, and a cost accumulated over a second horizon using a model of dynamics of the spacecraft governing an east-west position. A thruster controller to operate the thrusters according to their corresponding signals.

Abstract: A space based magnetic vortex accelerator and methods of use thereof having one or more sections of magnetic material configured as a conduit with a flightpath therethrough for the spacecraft, a magnetic coil field generator electrically connected to said one or more sections of magnetic material configured to generate a space based magnetic field via said one or more sections of magnetic material, a power plant electrically connected to said magnetic coil field generator, said power plant configured to power said magnetic coil field generator, one or more magnetic field receivers affixed to the spacecraft, said one or more magnetic field receivers configured to magnetically engage said space based magnetic field.

Abstract: 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.

Abstract: A propulsion device for controlling the orbit of an earth-orbit satellite including a structure of which the orientation is maintained constant in relation to the Earth in an operational configuration of the satellite in the orbit; a center of mass of the satellite being contained in the structure of the satellite, includes two thrusters suitable for delivering a thrust according to one axis, and fixed to the structure of the satellite in the same half-space separated by the plane of the orbit. The thrusters are arranged on either side of a plane containing the center of mass and perpendicular to a Z-axis; the thrusters being configured in such a way that a force resulting from the thrusts of the two simultaneously activated thrusters represents a principal component according to a Y-axis of the satellite oriented perpendicular to the orbit.

Abstract: A satellite comprises thrusters disposed with the firing directions each facing away from the mass center of satellite and different from each other. A control amount calculator calculates control amounts of the mean orbital elements from the mean orbital elements and the temporal change rates of the mean orbital elements set by an orbit determiner, and the target values. A distributor calculates firing timings and firing amounts of the thrusters for realizing the control amounts of the mean orbital elements by expressing a motion of satellite with orbital elements, solving an equation taking into account coupling of an out-of-plane motion and an in-plane motion due to thruster disposition angles and thruster firing amounts at multiple times, and combining one or more thruster firings controlling mainly an out-of-the-orbit-plane direction and one or more thruster firings controlling mainly an in-the-orbit-plane direction.

Abstract: Systems and methods are described herein for mounting a thruster onto a vehicle. A thruster mounting structure may comprise a first, second, and third rotational joint, a boom, and thruster pallet, and a thruster attached to the thruster pallet. The first rotational joint may be attached to the vehicle and configured to rotate in a first axis. The first rotational joint may be connected to the boom and configured to pivot the boom about the first axis. The boom may be connected to the second rotational joint, which is connected to the third rotational joint and configured to rotate the third rotational joint in the first axis. The third rotational joint may be connected to the thruster pallet and configured to pivot the thruster pallet in a second axis that is perpendicular to the first axis.

Abstract: An unmanned aerial vehicle (UAV) with omnidirectional thrust vectoring includes a central unit, a connective structure, and a plurality of propulsion units with omnidirectional thrust vectoring allowing a full six degrees of freedom. A vectored propulsion unit comprises thruster vectored by an omnidirectional mechanism and may include an autonomous sub-vehicle housed within a rotational frame, or an actuator-thruster assembly with directional control. A UAV with omnidirectional thrust vectoring includes a control system with a ground station unit, a central flight control unit, and a propulsion control unit. A plurality of vectored propulsion units working in coordination allows an unmanned aerial vehicle to maneuver with any stance or body orientation.

Abstract: A method and concept for employing a T-sin-alpha kill vehicle with energy flexibility is disclosed. The energy flexibility method applies divert pulses at multiple phases of the kill vehicle flight time and allows for range extension to increase the kill vehicle coverage of targets outside the normal reach, reaction to target updates, removal of navigation error, and homing divert to intercept the target. Each of these capabilities is essential to the successful intercept of exo-atmospheric ballistic targets in their midcourse phase of flight. A flight vehicle includes a main body, a number of attitude control mechanisms, a control unit, a divert system, a sensor unit, and an attitude control system. The divert system provides acceleration of the flight vehicle in a desired direction. The sensor unit tracks a target along a line of sight (LOS) of the sensor unit. The attitude control system maintains an orientation of the main body.

Abstract: Energy efficient satellite maneuvering is described herein. One disclosed example method includes maneuvering a satellite that is in an orbit around a space body so that a principle sensitive axis of the satellite is oriented to an orbit frame plane to reduce gravity gradient torques acting upon the satellite. The orbit frame plane is based on an orbit frame vector.

Abstract: Method and apparatus for controlling pressure in a pressure vessel. A plurality of valves between a pressure source and a pressure vessel can be selectively opened or turned off, singularly or in combinations, to control pressure in the pressure vessel. A maximum pressure threshold and a minimum pressure threshold can be established based on operating considerations of the pressure vessel. One or more of the valves can be turned on when the pressure in the pressure vessel reaches the minimum pressure threshold. One or more of the valves can be turned off when the pressure in the pressure vessel reaches the maximum pressure threshold.

Abstract: The systems and methods described herein include attitude determination and control system (ADCS) and associated methods. Systems for determining attitude may be used by various vehicle types, such as to determine the vehicle's attitude relative to an external point of reference. The ADCS may be used for passive or active stabilization of spin on multiple axes. The ADCS uses an incorporated autonomous control algorithm to characterize the effects of actuation of the system components and simultaneously trains its response to attitude actuators. This characterization generates and updates a movement model, where the movement model is used to indicate or predict the effect of one or more attitude actuators given vehicle state information.

Abstract: Energy efficient satellite maneuvering is described herein. One disclosed example method includes maneuvering a satellite that is in an orbit around a space body so that a principle sensitive axis of the satellite is oriented to an orbit frame plane to reduce gravity gradient torques acting upon the satellite. The orbit frame plane is based on an orbit frame vector.

Abstract: A propulsion system for the orbit control of a satellite in Earth orbit driven at a rate of displacement along an axis V tangential to the orbit comprises two propulsion modules, fixed to the satellite, and facing one another relative to the plane of the orbit, each of the propulsion modules comprising, in succession: a motorized rotation link about an axis parallel to the axis V; an offset arm; and a plate supporting two thrusters, suitable for delivering a thrust on an axis, arranged on the plate on either side of a plane P at right angles to the axis V passing through a center of mass of the satellite; each of the two thrusters being oriented in such a way that the thrust axes of the two thrusters are parallel to one another and at right angles to the axis V.

Abstract: A method controls an operation of a spacecraft according to a model of the spacecraft. The method determines control inputs for controlling concurrently thrusters of the spacecraft and momentum exchange devices of the spacecraft using an optimization of a cost function over a receding horizon subject to constraints on a pose of the spacecraft and constraints on inputs to the thrusters. The cost function includes components for controlling the pose of the spacecraft and a momentum stored by the momentum exchange devices. The method generates a command to control concurrently the thrusters and the momentum exchange devices according to at least a portion of the control inputs.

Abstract: A method controls an operation of a spacecraft according to a model of the spacecraft. The method determines control inputs for controlling concurrently thrusters of the spacecraft and momentum exchange devices of the spacecraft using an optimization of a cost function over a receding horizon subject to constraints on a pose of the spacecraft and constraints on inputs to the thrusters. The cost function includes components for controlling the pose of the spacecraft and a momentum stored by the momentum exchange devices. The method generates a command to control concurrently the thrusters and the momentum exchange devices according to at least a portion of the control inputs.

Abstract: The invention relates to a drive arrangement in a spacecraft, comprising several drive units (TW1,TW2,TW3), several individually controllable drive units that can be continuously applied to a common, constant voltage potential (HV), and a control of the axial thrust in the respective drive units is achieved due to the fact that the production of plasma in the respective drive units is individually controlled. In particular, the time-variable control of the production of plasma occurs by the time-variable control of the flow of neutral working gas (AG) in the ionization chamber (IK).

Abstract: Method and apparatus for controlling pressure in a pressure vessel. A plurality of valves between a pressure source and a pressure vessel can be selectively opened or turned off, singularly or in combinations, to control pressure in the pressure vessel. A maximum pressure threshold and a minimum pressure threshold can be established based on operating considerations of the pressure vessel. One or more of the valves can be turned on when the pressure in the pressure vessel reaches the minimum pressure threshold. One or more of the valves can be turned off when the pressure in the pressure vessel reaches the maximum pressure threshold.

Abstract: Systems and methods for orbit and attitude control of nanosatellites are provided. A spacecraft can be equipped with a plurality of pulsed ablative thrusters (PAT), mounted on at least one of the spacecraft body orientations. The PATs are integrated with the spacecraft structure. The actual spacecraft attitude is measured by a sensor and compared with the desired thrust direction. In order to reduce attitude errors, a control system is used to determine the firing sequence of thrusters. During maneuvering the thrusters are continuously being fired. To conserve energy a thrust switch control is utilized, selecting a single PAT to be fired each pulse. The result of this operation is that the attitude of the spacecraft is adjusted continuously. Therefore, thrust deviation from a selected path can be minimized during orbital maneuvering.

Abstract: Embodiments of the present invention provide an ion-thruster stationkeeping method and mounting configuration that reduces the propellant penalty when a single thruster fails, e.g., in the case where only three of a spacecraft's four ion thrusters are available. By improving firing efficiency for the single-thruster failure case, on-board propellant is reduced, thereby allowing increased payload mass. Also, the configuration supports both N/S and E/W stationkeeping using four ion thrusters (or three thrusters for the failure case) and therefore does not require a separate propulsion system or thrusters for E/W stationkeeping.

Abstract: A plasma thruster includes a plasma chamber having first and second axial ends, the first of which is open, an anode located at the second axial end, and a cathode. The cathode and anode are arranged to produce an electric field having at least a component in the axial direction of the thruster. A magnet system including a plurality of magnets is spaced around the thruster axis, each magnet having its north and south poles spaced around the axis.

Abstract: Embodiments of the present invention provide an ion-thruster stationkeeping method and mounting configuration that reduces the propellant penalty when a single thruster fails, e.g., in the case where only three of a spacecraft's four ion thrusters are available. By improving firing efficiency for the single-thruster failure case, on-board propellant is reduced, thereby allowing increased payload mass. Also, the configuration supports both N/S and E/W stationkeeping using four ion thrusters (or three thrusters for the failure case) and therefore does not require a separate propulsion system or thrusters for E/W stationkeeping.

Abstract: An air vehicle, such as a missile or a steerable submunition released from a missile or another air vehicle, has a bilateral thrust system for steering. The thrust system includes a pair of diametrically-opposed divert thrusters that provide thrust having radial components in opposite radial directions. In order to control the direction of thrust, the air vehicle controls rotation of the divert thrusters and/or timing of the firing of the thrusters. The air vehicle (or some part of the air vehicle that includes the divert thrusters) may be discretely rolled to position the divert thrusters to produce desired steering thrust. Alternatively, the air vehicle or part of the air vehicle may be continuously rolled, with the steering controlled by timing the thrust to the divert thrusters, such as by allocating thrust between the diametrically-opposed thrusters. Pressurized gas may be allocated between the two thrusters by use of pintle valve.

Abstract: A satellite inclination control method is provided. The method includes tracking optimal inclination vector control cycles for a satellite in near geosynchronous orbit, using control rates disposed to counter inclination growth of the satellite, where the control rates include continuously or quasi-continuously firings of a thruster, and where the control rates are disposed to provide convergence to the optimal inclination vector control cycles in the presence of variances in orbit determination, maneuver implementation and orbit propagation modeling errors.

Abstract: 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.

Abstract: A transport landing vehicle for transferring an astronaut to and from an extraterrestrial mass such as a moon, asteroid, or small planet is disclosed. The transport landing vehicle has a cage that is substantially open to the outside environment.

Abstract: A propulsion system for the orbit control of a satellite in Earth orbit driven at a rate of displacement along an axis V tangential to the orbit comprises two propulsion modules, fixed to the satellite, and facing one another relative to the plane of the orbit, each of the propulsion modules comprising, in succession: a motorized rotation link about an axis parallel to the axis V; an offset arm; and a plate supporting two thrusters, suitable for delivering a thrust on an axis, arranged on the plate on either side of a plane P at right angles to the axis V passing through a centre of mass of the satellite; each of the two thrusters being oriented in such a way that the thrust axes of the two thrusters are parallel to one another and at right angles to the axis V.

Abstract: A system and methods are provided for combining systems of an upper stage space launch vehicle for enhancing the operation of the space vehicle. Hydrogen and oxygen already on board as propellant for the upper stage rockets is also used for other upper stage functions to include propellant tank pressurization, attitude control, vehicle settling, and electrical requirements. Specifically, gases from the propellant tanks, instead of being dumped overboard, are used as fuel and oxidizer to power an internal combustion engine that produces mechanical power for driving other elements including a starter/generator for generation of electrical current, mechanical power for fluid pumps, and other uses. The exhaust gas from the internal combustion engine is also used directly in one or more vehicle settling thrusters. Accumulators which store the waste ullage gases are pressurized and provide pressurization control for the propellant tanks.

Abstract: An attitude control device for space station with system parameter uncertainties and on-orbit dynamic disturbances. A plurality of state sensors measure a plurality of states of the space station. An identification frequency selecting device selects an identification frequency. A moment of inertia identification operator calculation unit calculates a moment of inertia identification operator. A moment of inertia identification device calculates moment of inertia of the space station. A disturbance torque identification device calculates disturbance torque. A control torque calculation unit calculates a control signal. A plurality of thrusters generate a control torque based on the control signal.

Abstract: A method is provided for controlling a set of at least two satellites adapted to provide a service used by at least one portion of the set of the said satellites at a given moment, in which, continuously or pseudo-continuously, a mean value of the longitudes of the respective ascending nodes of each satellite is computed, and, for each satellite, a correction of trajectory of the satellite is applied by regulating the longitude of the ascending node on a setpoint equal to said current mean value.

Abstract: An orbit attitude control device includes a divert thruster including a plurality of nozzles. First group nozzles inject combustion gas in opposite directions along a first axis. Second group nozzles inject combustion gas in opposite directions along a second axis. A control section calculates correction values for opening degree commands based on a detection value of a pressure of the combustion chamber and a command value of the pressure, and corrects the opening degree command values by the correction values. The device further includes a first axis acceleration sensor for detecting acceleration along the first axis and a second axis acceleration sensor for detecting acceleration along the second axis. The correction values for the opening degrees of the first group nozzles are determined by a first axis acceleration, and the correction values for the opening degrees of the second group nozzles are determined by a second axis acceleration.

Abstract: An orbit attitude control device includes a plurality of nozzles for injecting combustion gas supplied from a combustion chamber, and a control section configured to calculate nozzle opening degree correction values so that a deviation between a detection value of the pressure of the combustion chamber and a command value becomes smaller. The control section is configured to calculate a total correction value so that the deviation between the detection value and the command values becomes smaller. A total value T1 for first group nozzles and a total value T2 for second group nozzles are calculated. The total correction value is distributed to the opening degree correction values for the first group nozzles with a ratio of T2/(T1+T2) and to the opening degree correction values for the second group nozzles with a ratio of T1/(T1+T2).

Abstract: An orbit attitude control device includes a plurality of nozzles and a control section. The nozzles inject a combustion gas supplied from a combustion chamber, opening degrees being controlled in accordance with opening degree command values. The control section calculates nozzle opening degree correction values for the opening degree command values in response to a detection value of a pressure of the combustion chamber and a command value for the pressure, and correct the opening degree command values by the nozzle opening degree correction values. Each nozzle opening degree correction value is determined based on each opening degree command value.

Abstract: Technology for predicting and correcting a trajectory is described. The technology can create a model to predict a position of the reusable launch vehicle at a time in the future; observe a wind condition during ascent of the reusable launch vehicle; store the observed wind condition in a wind map; predict during ascent a position and a terminal lateral velocity of the reusable launch vehicle at a terminal altitude; and correct a flight trajectory of the reusable launch vehicle based on the wind map.

Abstract: A system and a method for commanding a spacecraft to perform a three-axis maneuver purely based on “position” (i.e., attitude) measurements. Using an “inertial gimbal concept”, a set of formulae are derived that can map a set of “inertial” motion to the spacecraft body frame based on position information so that the spacecraft can perform/follow according to the desired inertial position maneuvers commands. Also, the system and method disclosed herein employ an intrusion steering law to protect the spacecraft from acquisition failure when a long sensor intrusion occurs.

Abstract: The invention set forth herein describes propulsive guidance methods and apparatus for controlling and shaping an atmospheric skip reentry trajectory for a space vehicle. Embodiments of the invention may utilize a powered explicit guidance algorithm to provide a closed-loop control method for controlling a space vehicle during a skip reentry maneuver.

Abstract: The present system and methods enable simultaneous momentum dumping and orbit control of a spacecraft, such as a geostationary satellite. Control equations according to the present system and methods generate accurate station-keeping commands quickly and efficiently, reducing the number of maneuvers needed to maintain station and allowing station-keeping maneuvers to be performed with a single burn. Additional benefits include increased efficiency in propellant usage, and extension of the satellite's lifespan. The present system and methods also enable tighter orbit control, reduction in transients and number of station-keeping thrusters aboard the satellite. The present methods also eliminate the need for the thrusters to point through the center of mass of the satellite, which in turn reduces the need for dedicated station-keeping thrusters. The present methods also facilitate completely autonomous orbit control and angular momentum control using.

Abstract: Provided is a method and system for maneuvering a first spacecraft relative to a nearby second spacecraft that occupies a finite volume of space including obstacles in the vicinity of the second from a measured present relative position to a desired ending relative position. A trajectory is computed for the first spacecraft from the present relative position to the ending relative position using the A* algorithm. One or more thrusters of the first spacecraft are then fired. The first spacecraft's relative position and velocity are then measured and compared to the computed trajectory.

Abstract: A control system for a vehicle having a dry dual clutch transmission (DCT) includes a launch condition detection module, a vehicle stop module, and a vehicle launch module. The launch condition detection module detects a launch condition based on whether (i) the vehicle is on an uphill grade and (ii) a driver of the vehicle has requested power via an accelerator. The vehicle stop module stops the vehicle when the launch condition is detected by (i) commanding an on-coming clutch of the dry DCT to a predetermined position and (ii) applying brakes of the vehicle. The vehicle launch module launches the vehicle after the vehicle is stopped by (i) fully engaging the on-coming clutch of the dry DCT and (ii) opening a throttle to a desired position corresponding to the power request.

Abstract: Provided are an attitude control system and method of a spacecraft of an artificial satellite that may enhance a maneuverability and a controllability by simultaneously applying a reaction wheel and a thruster among drive units used to maneuver an attitude of the spacecraft of the artificial satellite. The attitude control system may include: a thruster-based attitude controller which control firing time of thrusters mounted on the spacecraft; and a reaction wheel-based attitude controller controlling driving of a reaction wheel mounted on the spacecraft. The spacecraft may include a plurality of reaction wheels. When a defect occurs in the spacecraft due to a partial malfunction of the reaction wheels, an attitude maneuverability of the spacecraft may be corrected by simultaneously applying the thruster-based attitude controller and the reaction wheel-based attitude controller.

Abstract: The present system and methods enable simultaneous momentum dumping and orbit control of a spacecraft, such as a geostationary satellite. Control equations according to the present system and methods generate accurate station-keeping commands quickly and efficiently, reducing the number of maneuvers needed to maintain station and allowing station-keeping maneuvers to be performed with a single burn. Additional benefits include increased efficiency in propellant usage, and extension of the satellite's lifespan. The present system and methods also enable tighter orbit control, reduction in transients and number of station-keeping thrusters aboard the satellite. The present methods also eliminate the need for the thrusters to point through the center of mass of the satellite, which in turn reduces the need for dedicated station-keeping thrusters. The present methods also facilitate completely autonomous orbit control and control using Attitude Control Systems (ACS).

Abstract: A satellite longitude and drift control method is provided that includes providing a satellite that has a continuously or a quasi-continuously firing thruster, where the thruster is disposed to apply accelerations which counter a tri-axiality displacement in an orbit of the satellite, and the satellite thruster is disposed to achieve optimal ?V performance in the presence of orbit determination and orbit propagation errors. The method further includes targeting an optimal two-phase continuous acceleration target cycle using the continuously or the quasi-continuously firing thruster, providing a closed loop and a hybrid loop implementation of the thruster firing, where the hybrid loop implementation includes an open and closed loop implementation, and where the closed loop and the hybrid loop implementations are disposed to provide quasi-continuous implementations of an optimal continuous control program.

Abstract: Disclosed herein, in certain embodiments, is a method of altering the stability of unstable space debris. In some embodiments, the method further comprises changing the orbit of the unstable space debris.

Abstract: A satellite inclination control method is provided. The method includes tracking optimal inclination vector control cycles for a satellite in near geosynchronous orbit, using control rates disposed to counter inclination growth of the satellite, where the control rates include continuously or quasi-continuously firings of a thruster, and where the control rates are disposed to provide convergence to the optimal inclination vector control cycles in the presence of variances in orbit determination, maneuver implementation and orbit propagation modeling errors.

Abstract: A method for performing east-west station keeping for a satellite in an inclined synchronous orbit is described. The method includes averaging a value of a right ascension of the ascending node for an inclination vector associated with the satellite over a period of the control cycle, and managing corrections for the satellite such that an eccentricity vector, directed at perigee, is substantially collinear with the inclination vector.

Abstract: A system for providing attitude control with respect to a spacecraft is provided. The system includes a reaction wheel control module configured to control a number of reaction wheel assemblies associated with the spacecraft in order to control attitude, and a maneuver control module configured to use a number of gimbaled Hall Current thrusters (HCTs) to control the total momentum associated with the spacecraft. The total momentum includes the momentum associated with the reaction wheel assemblies and the angular momentum of the spacecraft. Using the gimbaled HCTs to control the momentum associated with the reaction wheel assemblies results in minimal HCT gimbal stepping.

Abstract: By sharing tasks between the CV and the KVs, the MKV interceptor provides a cost-effective missile defense system capable of intercepting and killing multiple targets. The placement of the acquisition and discrimination sensor and control sensor on the CV to provide target acquisition and discrimination and mid-course guidance for all the KVs avoids the weight and complexity issues associated with trying to “miniaturize” unitary interceptors. The placement of either a short-band imaging sensor and headlamp or a MWIR sensor on each KV overcomes the latency, resolution and bandwidth problems associated with command guidance systems and allows each KV to precisely select a desirable aimpoint and maintain track on that aimpoint to impact.