Abstract: A spacecraft is provided, which includes one or more of a centrally-oriented core, which includes a computing device. The computing device includes a processor and a memory, coupled to the processor, including computer instructions to control the spacecraft. The spacecraft may also include a power source, coupled to the core, a plurality of struts, each including a root end coupled the core and a distal end, the plurality of struts extending radially from the core. The spacecraft may also include a plurality of blade deployers, coupled to distal ends of the plurality of struts and a plurality of blades, coupled to the plurality of blade deployers and extending radially away from the core and in a common plane with the plurality of struts. The plurality of blades includes material configured to be deflected by solar pressure. Each of the struts is configured to provide damping to a corresponding blade.

Abstract: Provided are an artificial satellite and a method of controlling the same. The artificial satellite includes a main body flying along an orbit of a planet, an optical payload arranged on the main body to photograph a ground surface of the planet, and a pair of solar cell panels rotatably arranged on both sides of the main body in a first direction, wherein the first direction and a flight direction of the main body form an acute angle with each other.

Abstract: A space vehicle may extract and store energy, and also include a propulsion system. The space vehicle includes one or more wings connected to a body of the apparatus. Each of the one or more wings includes a propellant system configured to eject mass away from the apparatus, the ejection of the mass causes the apparatus to move from a first position to a second position.

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 method and apparatus for the control of the attitude of earth orbiting satellites and the orbit and attitude control of a novel gravitational wave detection satellite configuration located near the sun-earth Lagrangian points L3, L4 and L5, utilizing the control of solar radiation pressure by the use of electrically controllable variable reflection glass panels to provide the torques and forces needed.

Abstract: The present invention relates to a service satellite having a body, a controller and a docking unit. The docking unit includes at least two foldable, adjustable gripping arms pivotally mounted on the satellite body, each gripping arm being pivotable relative to the satellite body, and a gripping end at each free end of the gripping arms, wherein the gripping ends are adapted and configured to capture and grip a target portion of an orbiting satellite. Each gripping arm is controllable independently by the controller, which coordinates the motion of the arms.

Abstract: The disclosed system comprises one or more small satellites (e.g., CubeSats), one or more ground transmitters, and one or more downlink receivers to facilitate ground-to-space short-burst data communications. The CubeSats are miniaturized or small-form satellites that orbit the Earth transmitting data to and from the ground transmitters and the downlink receivers in low Earth orbit. To efficiently use its surface area, in various embodiments, the CubeSats are designed with deployable and folding wings such that the zenith-pointing side of the wings comprises solar panels and the nadir-pointing side of the wings comprises an antenna. In various embodiments, to increase the data transmission capacity of the CubeSats, the CubeSats comprise a deployable phased array antenna and a software defined radio.

Abstract: The present invention relates to a space-based instrument which provides continuous coronal electron temperature and velocity images, for a predetermined period of time, thereby improving the understanding of coronal evolution and how the solar wind and Coronal Mass Ejection transients evolve from the low solar atmosphere through the heliosphere for an entire solar rotation. Specifically, the present invention relates to using a 6U spherical occulter coronagraph CubeSat, and a relative navigational system (RNS) that controls the position of the spacecraft relative to the occulting sphere. The present invention innovatively deploys a free-flying spherical occulter, and after deployment, the actively controlled CubeSat will provide an inertial formation flying with the spherical occulter and Sun.

Abstract: A radiator for a satellite intended for being placed in geostationary orbit around the earth in a tilted plane relative to the plane of the ecliptic, includes at least one panel having at least one radiative surface, and including: a mounting foot supporting the panel; and control and motor elements for pivoting the mounting foot about an axis of rotation tilted relative to the radiative surface which is perpendicular to a radiation axis, the radiation axis and the axis of rotation being tilted relative to one another by a non-zero working angle, corresponding to the tilt angle of the plane of the orbit of the satellite relative to the plane of the ecliptic, the working angle being fixed, such that for any rotation of the mounting foot about the axis of rotation owing to the control and motor elements, the radiative surface remains parallel to the plane of the ecliptic.

Abstract: An electric propulsion device for a satellite equipped with at least four active thrusters exerting a parallel thrust upon a transfer, the device comprises means for detecting a thruster failure and means for reorienting the thrusters, and comprises means for computing a reorientation angle of the thrusters remaining active upon a failure of a thruster, the value of the angle being computed to reorient at least two of the remaining thrusters in order to cancel the total torque about the center of mass of the satellite.

Abstract: A directionally-controlled roll-out elastically deployable solar array structure is disclosed. The structure includes one or more longitudinal elastic roll out booms that may be closed section or open section to allow for efficient rolled packaging onto a lateral mandrel. A flexible photovoltaic blanket is attached to a tip structure and to a lateral base support structure, but remains uncoupled from the longitudinal booms. The solar array system may be stowed simultaneously into a rolled package comprised of the roll out booms and the flexible planar blanket together, or onto independent rolls. Alternatively, the system may be stowed by rolling the booms, and accordion Z-folding the hinged flexible photovoltaic blanket into a flat stack. Structural deployment is motivated by the elastic strain energy of the roll out booms, and several methods of deployment direction control are provided to ensure a known, controlled, and unidirectional deployment path of the elastically unrolling booms.

Abstract: A plurality of orbiting solar generators stay in constant touch. They can be congregated rapidly in space at any desired secret location. Once congregated they all discharge their energy to a death star. This death star could be a newly launched ICBM. A laser generator uses this newly acquired energy on the death star to project a non-nuclear laser ray to a target. The target could be a city, a ship or a satellite. In the event of an asteroid approaching earth, this system could destroy an asteroid. In peacetime the orbiting solar generators could supply electric power to an earth based power grid.

Abstract: A device for controlling the attitude of a satellite exploiting solar pressure, includes at least two solar generators destined to be arranged on either side of a central body of the satellite and each having one face to be exposed to the Sun, referred to as “front face”, the device also including at least three surfaces whose optical properties can be commanded. The surfaces whose optical properties can be commanded are arranged on flaps connected to solar generators, each flap being fixed with respect to the solar generator to which it is connected, and such that, in the operating position, at least two of the surfaces are not parallel when the front faces of the solar generators are optimally oriented with respect to the Sun. The device further includes a module for commanding the optical properties of each surface whose optical properties can be commanded.

Abstract: A method of controlling the attitude of a satellite in orbit around a celestial body. The attitude of the satellite being controlled by a momentum storage device and controllable surfaces of the satellite configured to create desaturation torques in the storage device by using solar pressure. The controllable surfaces are arranged on solar panels mobile in rotation around an axis Y. At least one electric thruster configured to control the orbit of the satellite also controls the attitude of the satellite. The orientation of the electric thruster is controlled to activate the electric thruster with a thrust direction deliberately not aligned with a center of mass of the satellite to create desaturation torques in the storage device along axis Y. The controllable surfaces are controlled to create desaturation torques of the storage device in a plane orthogonal to the Y axis.

Abstract: A thin membrane structure for stabilizing a spacecraft is provided. The spacecraft has a first end and a second end. The spacecraft has a center of pressure and a center of gravity. The thin membrane structure comprises a module secured to the spacecraft and a structure having a polygonal base and a plurality of triangular side panels meeting in a point opposite the base with the point secured to the module. Prior to deployment, the structure is entirely contained within the module. Subsequent to deployment, the structure expands to a pyramidal shape with the distance between the center of pressure and the center of gravity increasing to a length greater than approximately one-half the length of the spacecraft.

Abstract: An apparatus includes a light foil device configured to move based on radiation pressure associated with light received by the light foil device. The apparatus includes a mechanism configured to transition between operational states in response to the movement of the light foil device, or includes a valve configured to control a flow of material through a conduit based, at least in part, on the movement of the light foil device.

Abstract: A device for controlling the attitude of a satellite exploiting solar pressure, includes at least two solar generators destined to be arranged on either side of a central body of the satellite and each having one face to be exposed to the Sun, referred to as “front face”, the device also including at least three surfaces whose optical properties can be commanded. The surfaces whose optical properties can be commanded are arranged on flaps connected to solar generators, each flap being fixed with respect to the solar generator to which it is connected, and such that, in the operating position, at least two of the surfaces are not parallel when the front faces of the solar generators are optimally oriented with respect to the Sun. The device further includes a module for commanding the optical properties of each surface whose optical properties can be commanded.

Abstract: A method for controlling the attitude of a satellite in orbit around a celestial object, the satellite including an observation instrument, a solar panel, a radiator and a star sensor which are arranged on the satellite such that, in a reference frame associated with the satellite and defined by three orthogonal axes X, Y, and Z, the observation instrument has its observation axis parallel to the Z-axis, the solar panel is parallel to the Y-axis, the radiator is arranged on one of the sides ?X, +Y, or ?Y of the satellite, and the star sensor points to the negative X values side. The roll and pitch attitudes of the satellite are controlled during an activity period to direct the observation instrument towards areas of the celestial object to be observed, and the yaw attitude of the satellite is controlled to keep the sun on the positive X values side and ensure that a solar panel minimum insolation constraint is satisfied during observation phases of the activity period.

Abstract: A solar sail spacecraft is designed to steer and move in space by using solar radiation pressure as a driving force, therefore allowing fuelless propulsion, station keeping and attitude control. A solar power satellite utilizes thrusters only to stay in an rather stationary orbit. Its purpose is, to collect energy and transfer it to a given location, usually to Earth. The intention of the present invention is to create a hybrid of a solar sail spacecraft and a power satellite for space based power generation and transmission, which is mobile and provides both, fuelless solar sailing and electric thrusters as means of propulsion. The mobile Solar Sail Power Station serves as solar energy collector and can be connected by docking with other power stations and with a transmitter unit for energy transmission, whereby the transmitter features its own fuelless pointing and attitude control devices.

Abstract: One embodiment of the invention includes a spacecraft. The spacecraft comprises at least one solar array panel comprising an array of solar cell sections. Each of the solar cell sections can be configured to generate electrical power from received solar radiation. The spacecraft also comprises a solar array selection controller configured to selectively deactivate a portion of the array of solar cell sections to generate a torque on the spacecraft based on a difference in at least one of solar and thermal radiation pressure between an activated portion of the array of solar cell sections and the deactivated portion of the array of solar cell sections.

Abstract: Fuel less ACS for solar sails, using furl- and unfurl able ballast-sail-foil-segments for simultaneously displacement of center of mass and center of solar radiation pressure into opposite directions to each other. Solar-Sail-Launch-System for direct launch of the System-Sail including already docked in daughter units and payload in the sailcraft's central docking station. Unlike todays launch able solar sail designs the System-Sail features ample solar cell arrays and additional SEP-thruster-units for steering and propulsion, while the solar sail rather serves for longtime fuel less attitude controls and station keeping. The SEP-Sailcraft may also serve as a carrier-ship for daughter-units in asteroid exploration missions and is able to deliver prospector landers back to LEO with furled in foils.

Abstract: A satellite intended to travel in a constellation of satellites in an area of space in which the dominant disturbing forces and torques are for the most part caused by differential solar pressure between the satellites of the constellation comprises a satellite structure and a sunshield to prevent at least a portion of the satellite structure from being illuminated by solar rays. The reflectivity of the reflective surfaces of the sunshield is adjusted as a function of the angle of incidence of the solar rays.

Abstract: Fuel less ACS for solar sails, using furl- and unfurl able ballast-sail-foil-segments for simultaneously displacement of center of mass and center of solar radiation pressure into opposite directions to each other. Solar-Sail-Launch-System for direct launch of the System-Sail including already docked in daughter units and payload in the sailcraft's central docking station. Unlike todays launch able solar sail designs the System-Sail features ample solar cell arrays and additional SEP-thruster-units for steering and propulsion, while the solar sail rather serves for longtime fuel less attitude controls and station keeping. The SEP-Sailcraft may also serve as a carrier-ship for daughter-units in asteroid exploration missions and is able to deliver prospector landers back to LEO with furled in foils.

Abstract: A spacecraft including control vanes for controlling the pointing direction of the spacecraft by providing a variable absorptive, reflective, emissive and/or transmissive properties. The control vanes provide a torque on the spacecraft to maintain the spacecraft pointing towards the sun. The control vanes can include at least one xb-axis control vane and at least one yb-axis control vane where the xb axis control vane provides xb-axis control torque on the spacecraft rotated about the xb-axis, and the yb-axis control vane provides yb-axis control torque on the spacecraft when rotated about the yb-axis.

Abstract: The present invention provides a method for the attitude control of satellites in elliptic orbits or satellites initially placed in circular orbits perturbed to elliptic orbits due to environmental disturbances. The method relies on the application of solar radiation pressure to provide the desired torque for the satellite attitude control. The satellite is equipped with two-oppositely placed light-weight solar panels extending away from the satellite along a predetermined direction (satellite body fixed Y-axis). By rotating one of these solar panels or both of them through desired angles about their axis using the respective driver motors as per the simple open-loop control law, the torque about the satellite axis is developed to achieve the desired attitude performance.

Abstract: A spacecraft comprises a main body; at least one elongated solar wing extending from the main body, defining a generally flat plane and comprising a pair of longitudinally extending side edges; at least one other component or structure extending from the main body and spaced at a separation distance from the at least one solar wing; and at least one solar trim tab coupled to the at least one solar wing, linearly elongated and extending in the generally flat plane in a direction transversely away from one of the longitudinally extending side edges, and sized and positioned along the longitudinally extending side edge for counteracting or compensating for one or more types of disturbance torques.

Abstract: Controlling the solar torque imposed on a spacecraft (10) in flight by providing a film (52) with variable absorptive, reflective, emissive and/or transmissive properties on the sun side of a thermal shield (50) of the spacecraft (10). As the orientation of the thermal shield (50) changes relative to the sun line, the absorptive, reflective, emissive and/or transmissive properties of the shield (50) change to cause the shield's (50) center of solar pressure to change, thus aligning it with the spacecraft (10) center of mass (24) as viewed from the direction of the sun line. In accordance with another embodiment of the invention, the spacecraft (100) is provided with a plurality of control vanes (110–116) that have a variable absorptive, transmissive, reflective and emissive property to maintain the spacecraft (100) stably pointed towards the sun.

Abstract: A method and system for minimizing the solar array sun tracking disturbance is disclosed. The method separates the North solar array wing stepping and South solar array wing stepping in time, and use the disturbance caused by one solar array wing to cancel the disturbance caused by the other solar array wing. It separates the step times of these two solar arrays by a half cycle of the array frequency excited by the solar wing drive stepping. Because of the symmetry between the North and South solar arrays, their disturbances cancel each other out.

Abstract: Controlling the solar torque imposed on a spacecraft (10) in flight by providing a film (52) with variable absorptive, reflective, emissive and/or transmissive properties on the sun side of a thermal shield (50) of the spacecraft (10). As the orientation of the thermal shield (50) changes relative to the sun line, the absorptive, reflective, emissive and/or transmissive properties of the shield (50) change to cause the shield's (50) center of solar pressure to change, thus aligning it with the spacecraft (10) center of mass (24) as viewed from the direction of the sun line. In accordance with another embodiment of the invention, the spacecraft (100) is provided with a plurality of control vanes (110-116) that have a variable absorptive, transmissive, reflective and emissive property to maintain the spacecraft (100) stably pointed towards the sun.

Abstract: Controlling the solar torque imposed on a spacecraft (10) in flight by providing a film (52) with variable absorptive, reflective, emissive and/or transmissive properties on the sun side of a thermal shield (50) of the spacecraft (10). As the orientation of the thermal shield (50) changes relative to the sun line, the absorptive, reflective, emissive and/or transmissive properties of the shield (50) change to cause the shield's (50) center of solar pressure to change, thus aligning it with the spacecraft (10) center of mass (24) as viewed from the direction of the sun line. In accordance with another embodiment of the invention, the spacecraft (100) is provided with a plurality of control vanes (110-116) that have a variable absorptive, transmissive, reflective and emissive property to maintain the spacecraft (100) stably pointed towards the sun.

Abstract: A spacecraft docks with a spinning and/or rotating asteroid, meteoroid, comet, or other space object, utilizing a tether shaped in a loop and utilizing subvehicles appropriately to control loop instabilities. The loop is positioned about a portion of the asteroid and retracted thereby docking the spacecraft to the asteroid, meteoroid, comet, or other space object. A deployable rigidized, photon momentum transfer plane of sufficient thickness may then be inflated and filled with foam. This plane has a reflective surface that assists in generating a larger momentum from impinging photons. This plane may also be moved relative to the spacecraft to alter the forces acting on it, and thus on the asteroid, meteoroid, comet, or other space object to which it is attached. In general, these forces may be utilized, over time, to alter the orbits of asteroids, meteoroids, comets, or other space objects.

Abstract: A large membrane space structure deployed and spanned by centrifugal force owing to the spin motion, contains a hub located at a central portion thereof and a sail including a plurality of petals attached to the hub by supports. Each of the petals has regions symmetrical to an imaginary center line passing through the center of the hub. Membranes are spanned on the regions. Each of the membranes is divided into parts of suitable shapes, and adjacent membranes are discretely connected to each other by bridge belts to suppress the residual crease strain. The petals are symmetric with respect to the center of the hub. Deployment force is provided in the circumferential direction by the introduction of imaginary tension lines. The petals may be connected to each other to help deployment.

Abstract: A method and apparatus for autonomous navigation for deep space missions using the sun as the reference body and determining the spacecraft orbit based on observations made on the sun using onboard instruments. Two types of observation data, the direction of the spacecraft relative to the sun as a function of time and the optical Doppler shift due to the motion of the spacecraft relative to the sun, can be used for the spacecraft orbit determination. A dual imaging system which functions as a sun imager taking images of the sun against star backgrounds during the cruise phase and as a regular optical imager taking pictures of the targeting planetary body during the approaching phase is also described.

Abstract: A supporting structure for a solar sail of a satellite is formed by support arms which are connected in a swiveling manner with a solar panel through unfolding joints, and a film is stretched between the support arms. A longitudinal connector is arranged parallel to one side edge of the solar panel, which has support arms that are arranged in a joint direction in the plane of the film and form at least one U-shaped supporting structure between which the film of the solar sail can be stretched. Corner connectors are arranged in the interior angle areas between the longitudinal connector and the support arms. This arrangement simplifies known constructions while maintaining the existing functional safety in order to allow for achieving a noticeable weight reduction.

Abstract: The present invention is directed to spacecraft that have, for any reason, lost the spacecraft's service attitude that permits it to carry out the service operations for which it was designed. The invention provides methods and structures for acquiring and determining a power-safe attitude (i.e., one in which wing current is sufficient to support the spacecraft's housekeeping operations) from which the spacecraft can be subsequently returned to a service attitude. The methods are particularly useful because they a) require only a single star tracker for sensing attitude, comprise simple maneuvers, and typically acquire a power-safe attitude that does not significantly differ from the spacecraft's service attitude to thereby reduce the spacecraft's return-to-service time.

Abstract: A large membrane space structure deployed and spanned by centrifugal force owing to the spin motion, contains a hub located at a central portion thereof and a sail including a plurality of petals attached to the hub by supports. Each of the petals has regions symmetrical to an imaginary center line passing through the center of the hub. Membranes are spanned on the regions. Each of the membranes is divided into parts of suitable shapes, and adjacent membranes are discretely connected to each other by bridge belts to suppress the residual crease strain. The petals are symmetric with respect to the center of the hub. Deployment force is provided in the circumferential direction by the introduction of imaginary tension lines. The petals may be connected to each other to help deployment.

Abstract: A method and apparatus for autonomous navigation for deep space missions using the sun as the reference body and determining the spacecraft orbit based on observations made on the sun using onboard instruments. Two types of observation data, the direction of the spacecraft relative to the sun as a function of time and the optical Doppler shift due to the motion of the spacecraft relative to the sun, can be used for the spacecraft orbit determination. A dual imaging system which functions as a sun imager taking images of the sun against star backgrounds during the cruise phase and as a regular optical imager taking pictures of the targeting planetary body during the approaching phase is also described.

Abstract: A spacecraft includes an articulating sunshield assembly that is capable of simultaneously performing thermal control functions and solar torque balancing for the spacecraft. The sunshield assembly includes a pair of shield members that can be controllably positioned as the spacecraft orbits about a primary body. Control functionality is provided for periodically adjusting the positions of the shield members to maintain a neutral solar torque stability condition for the spacecraft. In one embodiment, solar torque balancing is performed in each of three independent rotational directions or planes (i.e., roll, pitch, and yaw) using the sunshield assembly. Functionality is also provided for performing momentum dumping tasks using the sunshield assembly in place of, or in conjunction with, on-board thrusters.

Abstract: Orientation system and process of an artificial satellite in low orbit. Aerodynamic control surfaces producing rotations of the satellite by upper-layer atmosphere are combined along two axes to magnetic couplers (1, 2, 3) producing rotating movements along the three principal axes of pitch, roll and yaw thanks to the Earth's magnetic field. Great precision may be obtained in orienting the satellite without substantial energy consumption. Command laws are provided.

Abstract: The space-based solar power generating system is comprised of a flexible thin film photovoltaic sheet supported as a sail in the solar wind. The solar wind provides pointing support, deployment support, and structure stiffness without a heavy backup structure. A high Isp electric propulsion system is used to counteract the force exerted on the sail by the solar wind.

Abstract: A spacecraft having a pair of asymmetrical side-mounted antennas that are designed to control the net angular momentum of the spacecraft over a twenty-four hour period. One of the side-mounted antennas is a dual surface antenna having a front surface that has a reflective sunshield overlay thereon and a rear surface. The rear surface of this side mounted antenna has a reflective blanket attached directly to the rear surface of the antenna that has low-&agr; properties to control the solar or radiation force acting on the spacecraft.

Abstract: Methods that provide stationkeeping maneuvering of a yaw steered spacecraft that orbits around a central body, such as the Earth, and experiences solar radiation pressure produced by the sun. The methods comprise the following steps. A spacecraft having a solar array is launched into orbit at a desired orbital location. Once the spacecraft is in orbit at the desired orbital location, a reflected component of the solar radiation pressure is caused to selectively apply a force to the spacecraft that moves the spacecraft to perform stationkeeping maneuvers. The reflected component of the solar radiation pressure may be caused to selectively apply a force to the spacecraft in two exemplary ways. In one embodiment, the spacecraft is yaw steered to follow a yaw steering profile so that the axis of the solar array is substantially normal to a plane containing the sun vector and nadir vector.

Abstract: A method for controlling orbiting spacecraft uploads a plurality of parameters to an onboard processor, the parameters including a plurality of quaternion elements describing an inertial to orbit reference frame, and including radial position, radial velocity and angular rate of the spacecraft. Parameters are input for processing one of a plurality of propagation algorithms, preferably calculating said propagation algorithms with the uploaded parameters, computing enhanced time of day vectors, and computing ground time of day angles from the enhanced time of day vectors for adjusting the payload pointing angle, such as an antenna pointing angle, of the satellite. Preferably, the calculating step comprises integrating an orbital state vector with a second order Runge-Kutta integration algorithm. In addition, enhanced time of day fault processing provides an internal check on integration accuracy and is checked every time of day update.

Abstract: Control moment gyros in an array are rotated to reorient a satellite. Gyro angle is selected from one of three values based upon whether the stored angular momentum for the desired angle is below a singularity free value, greater than the singularity free value or is greater than the maximum available stored angular momentum.

Abstract: A passive device for stabilizing the pointing direction of a spacecraft of the type comprising a pair of panels that are symmetrical about a gyroscopic stabilization axis, each panel having an auxiliary flap that is at least partially reflecting. Each of the auxiliary flaps is spaced apart from the plane of the corresponding panel and is disposed relative thereto in such a manner that during rotation of the spacecraft about the stabilization axis the area of the flaps that is illuminated by the sun's rays emitted along the solar ray direction Z.sub.s is modulated during rotation by the shadow of the corresponding panel.

Abstract: Solar wing positioning methods are provided which favorably reduce seasonal variation of generated power in a satellite while simultaneously managing the composite system influence that off-pointed solar wing operation imposes on the satellite. The composite system influence includes environmental torques and may also include other system influences such as wing-to-body thermal radiation, thruster plume impingement and antenna/sensor field of view encroachment. In the simplest method embodiment, the solar wings are tilted asymmetrically from a nominal position to reduce seasonal power variations and are further tilted symmetrically to generate a solar pressure torque component which, on a diurnal average basis, compensates a gravity gradient torque component that is substantially generated by the net, off-pointed configuration of the wings.

Abstract: A device for angularly positioning a solar panel equipping a spacecraft such as a satellite, the panel being connected in hinged manner to the body of the spacecraft. The device comprises a heat-sensitive drive mechanism suitable for causing the panel to be displaced relative to the body of the spacecraft automatically as a function of the direction of incidence of the solar radiation on the spacecraft. The drive mechanism is suitable for taking up two states as a function of its temperature, and is so disposed on the spacecraft that a change in the direction of incidence of the solar radiation on the spacecraft is accompanied by a change in the temperature of the drive mechanism causing a change of a state therein and a change in the angular position of the panel tending to reduce the angle of incidence of the solar radiation on the panel.

Abstract: One or more deployable thermal panels (24, 28, 70) are actively controlled throughout the orbit of a satellite (20) to provide thermal dissipation. Adjusting the incident angle between the panel (24, 28, 70) and the sun and controlling the flow of fluid through optional flexible heat pipes loads and unloads heat to provide thermal stability for components (62) which have special thermal requirements. An optional antenna panel (70) on a nadir side (64) of the satellite (20) offers an antenna side (74) on one surface and a thermal radiating side (72) on an opposing surface. In addition, thermal panel movements are controlled (96) to provide counter-disturbance torques (140).

Abstract: A method in accordance with this invention for maintaining a spacecraft in a desired orbital configuration, comprises the steps of: (a) recording a history of yaw momentum stored in momentum wheels; (b) estimating an average inertial torque and momentum over a previous time interval (such as one day); (c) determining a desired change in inertial torques using PID control law; (d) commanding a change in satellite trim tab and solar array position from a desired change in solar torque; and (e) slewing the trim tab and solar array a desired amount.

Abstract: A spacecraft traveling in a volume of space receiving radiation from a radiation source and having a spacecraft body having a first axis of symmetry, X, a second axis of symmetry, Y, and a third axis of symmetry, Z. The spacecraft body rotates about a rotation axis, T, which defines a nonzero angle of inclination .lambda. relative to the Z axis. A radiation receiving element is rotatably attached to the spacecraft body along an axis, S. A control system is employed on the spacecraft for rotating the spacecraft body about the rotation axis T by an angular amount .gamma. and rotating the radiation receiving element by an amount so that the radiation receiving element is normal to the radiation source.