Abstract: 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).

Abstract: 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).

Abstract: A rotor assembly includes a rotor assembly housing, a shaft, a bearing assembly coupling the shaft to the rotor assembly housing, and a mass structure coupled to and rotatable with the shaft. The bearing assembly includes a bearing housing, a first raceway defined in the bearing housing, a second raceway defined in the shaft, and a plurality of ball bearings positioned within the first and second raceways to enable the shaft to rotate relative to the rotor assembly housing.

Abstract: A valve is provided for use on a control moment gyroscope (CMG) having a housing separating an internal environment from an external environment. The valve includes a valve housing, a valve element, and bellows. The valve housing is configured to couple to the CMG housing and includes an inner surface defining a cavity, an outer surface, and an opening extending therebetween. The valve element is disposed within the valve housing cavity and is movable between a closed position, in which fluid is prevented from flowing through the valve housing opening, and an open position, in which fluid may flow through the valve housing opening. The bellows is disposed within the valve housing and coupled to the valve element and has an internal chamber. The bellows selectively moves the valve element closed and open in response to a differential pressure between the bellows internal chamber and the valve housing cavity.