Abstract: A torque reaction/momentum wheel device for attitude control of a body, such as a spacecraft, having a motor driven flywheel with the flywheel at one end of a shaft and cantilevered with respect to at least two bearings which support the shaft which is common to the motor and flywheel, all having substantially the same spin axis. A housing which supports the motor and bearings is located all on one side of the flywheel which allows the flywheel to be balanced while mounted onto the shaft thus reducing dynamic unbalance forces. A cover is placed over the flywheel, motor, and housing so that the torque reaction/momentum wheel device can be pressurized which is necessary to prevent the bearing lubricant from migrating or evaporating out of the bearings. The bearings are lubricated by a grease which has low drag torque characteristics. This grease is a diester based oil with a lithium soap additive and filtered so that all particles are less than 10 microns in size.