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: 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: 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 system (300) for determining the ephemeris and attitude for a spacecraft includes ephemeris and attitude determining subsystems (700, 800) that obtain ephemeris data (708, 806) for one or more reference spacecraft crosslinked to the spacecraft. Crosslink sensor pointing information (706, 802) is obtained for the crosslink sensors. The satellite ephemeris and attitude (712, 810) are then calculated with ephemeris and attitude determination algorithms (702, 804) based on the ephemeris data (708, 806) and crosslink sensor pointing information (706, 802). Other available information, such as stored results of previous measurements and calculations, time (710, 808), spacecraft attitude (704), information from non-crosslink sensors and ranging information may be used to enhance the accuracy or decrease the complexity of the ephemeris calculations.

Abstract: An RF beam pointing apparatus (500, 600) compensates for the effects of settling errors on antenna pointing. The beam pointing apparatus includes an attitude reference system (502, 528, 530, 534) generating an antenna attitude output from the satellite attitude. Also included is attitude comparison circuitry (528, 530), coupled to the attitude reference system, that includes an antenna pointing error output. Control circuitry (528, 530) is coupled to the attitude reference system (502, 528, 530, 534) and the attitude comparison circuitry (528, 530). The control circuitry (528,530) directs the attitude comparison circuitry (528, 530) to generate control error output signals in response to dynamic settling antenna pointing errors induced by a mechanical slew on the satellite.

Abstract: The present invention provides a system (200) for determining the ephemeris and attitude for a spacecraft based on optical payload pointing directions and the ephemeris of other spacecraft. An ephemeris determining subsystem (300) obtains ephemeris data (308) for one or more reference spacecraft. Optical payload pointing information (306) is obtained for the optical payload pointed to the reference spacecraft. The spacecraft ephemeris (312) is then calculated with ephemeris determination algorithms (302) based on the ephemeris data (308) and optical payload pointing information (306). Other available information, such as stored results of previous measurements and calculations, time (310), spacecraft attitude (304), information from non-payload sensors and ranging information may be used to enhance the accuracy or decrease the complexity of the ephemeris calculations. Spacecraft attitude can also be determined using reference spacecraft ephemeris data and optical payload pointing information.

Abstract: A compact delay stage for phase delaying a light signal to provide increased amounts of phase delay to a light signal. A plurality of reflective structures are configured to provide a delay path to the light signal. One of the reflective structures is configured to accept the light signal and direct the light signal between the reflective structures a predetermined selectable number of times until the light signal has completed the delay path thereby translating the light signal into a delay signal. One of the reflective structures is configured to provide egress to the delayed signal to exit the compact delay stage.

Abstract: The present invention provides a system (200) for determining the ephemeris of a space vehicle based on distances to and ephemeris of other spacecraft. An ephemeris determining subsystem (300) obtains ephemeris data (308) for one or more reference spacecraft. Distance information (306) is obtained between the space vehicle and the reference spacecraft. The spacecraft ephemeris (312) is then calculated with ephemeris determination algorithms (302) based on the ephemeris data (308) and distance information (306). Other available information, such as stored results of previous measurements and calculations, time (310), information from other on-board sensors and attitude information may be used to enhance the accuracy or decrease the complexity of the ephemeris determination.

Abstract: A system for and a method of controlling the temperature of an object (22). Temperature sensors (30) are placed on the object (22) in abutting zones (24) substantially covering a surface of the object (22), so as to detect a temperature in each of the respective zones (24). Temperature adjusting elements (28) are spaced from and thermally coupled to the object (22), to adjust the temperatures of corresponding ones of the respective zones (24). Temperature control circuits (32, 34, 36), responsive to temperatures detected by respective ones of the temperature sensors (30), control the corresponding ones of the temperature adjusting elements (28) to maintain the temperatures of the respective zones (24) within a preset temperature range. When the object (22) is in a cold environment and is to be maintained at a warmer temperature, the temperature adjusting elements (28) are heating elements.