Embodiments of three parameter isolators including rolling seal damper assemblies are provided. In one embodiment, the three parameter isolator includes first and second isolator end portions, which are opposed along a working axis. A main spring and a tuning spring are mechanically coupled in parallel between the first and second isolator end portions. A rolling seal damper assembly is further mechanically coupled between the first and second isolator end portions in parallel with the main spring and in series with the tuning spring. The rolling seal damper assembly includes a first hydraulic chamber, a second hydraulic chamber fluidly coupled to the first hydraulic chamber, and first and second rolling diaphragm seals partially bounding the first and second hydraulic chambers, respectively. In certain implementations, the rolling seal damper assembly also contains a thermal compensator piston to which the first rolling diaphragm seal is attached.

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.

Reaction wheel assemblies having relatively compact and lightweight form factors (referred to as small scale RWAs) are disclosed. Such small scale RWAs are well-suited for deployment onboard relatively small satellites, but are not restricted to usage within any particular device or platform. In one embodiment, the small scale RWA includes a primary support platform to which a rotor is coupled for rotation about a spin axis. An axially-expanded face-to-face (DF) duplex bearing pair is disposed between the rotor shaft and the support platform. The DF duplex bearing pair includes first and second rolling element bearings positioned around an intermediate portion of the rotor shaft. The first and second rolling element bearings have first and second bearing load lines, respectively, which are spaced by a tailored bearing load line separation (SLL).

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.

Methods and apparatus are provided for a controlled motor assembly for use in a reaction wheel assembly (RWA). The controlled motor assembly is optimized to work with an AC motor, and includes a filter configured to inhibit electrical and electromagnetic noise from being coupled between a spacecraft power bus and a power bus internal to the RWA, as well as an arrangement of power switch elements providing a path for motor phase currents associated with the AC motor. A digital control system is implemented to receive a command input, position sensor feedback and to retrieve parameters associated with the AC motor from a memory device. Based on the command input, the position sensor feedback and the parameters associated with the AC motor, the digital control system controls activation for the arrangement of power switch elements, and generates data output.

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.

A magnetic levitation reaction sphere includes a spherical-housing-shaped rotor and three groups of stators. Each group includes two stators using the sphere center of the rotor as a symcenter. Axes of the three groups are mutually orthogonal. Each stator comprises a stator core and a coil array. An air gap is reserved between an inner surface of each stator core and the outer surface of the rotor. Through grooves are radially formed in the stator cores. The coil arrays are disc-type motor stator windings. Two effective sides of each coil in each coil array are respectively placed in two through grooves of the corresponding stator core. The magnetic levitation reaction sphere has low cost; levitation and rotation driving are integrated; the magnetic levitation reaction sphere has a simple and compact structure, a small size and a low mass, and relates to inherent stable levitation; and the levitation control is simple.

An inertial actuation magnetohydrodynamic wheel (2) comprising a torus-shaped fluid ring (3) filled with a conductive liquid, at least one effective area (24, 26, 28) for setting the liquid into motion, and at least one magnetohydrodynamic pump (4, 6, 8). The ratio of the set back distance of any magnetic conduction element (24, 26, 28) of the air gap of any electromagnetic pump (4, 6, 8) over the internal size of the fluid ring (3) is greater than or equal to 0.5 and the fluid ring (3) comprises at least two distinct effective areas (24, 26), for setting the conductive liquid into motion, angularly spaced apart by at least 120.

A method to control a sunlight acquisition phase of a spacecraft with a nonzero angular momentum of an axis D.sub.H. The spacecraft includes a solar generator configured to rotate about an axis Y. The spacecraft actuators are controlled to place the spacecraft in an intermediate orientation in which the axis Y is substantially orthogonal to the axis D.sub.H. The solar generator is controlled to orientate the solar generator towards the sun. The spacecraft actuators are controlled to reduce the angular momentum of the spacecraft. The actuators of the spacecraft engine are controlled to place the spacecraft in an acquisition orientation in which the axis Y is substantially orthogonal to the direction of the sun with respect to the spacecraft.

A passive thermal system for use in a satellite and other aerospace applications includes a container having a heat-pipe working fluid disposed in a first chamber and a Phase Change Material (PCM) disposed in a second chamber that substantially surrounds the first chamber. The first chamber contains a wick for transporting the heat-pipe working fluid. The exterior of the first chamber has fins, etc., that extend into the PCM for heat spreading and increased interface area.