Abstract: An alignment positioning mechanism for correcting and compensating for misalignment of structures to be coupled thereby. The mechanism comprises a power screw 12 with a base portion 13 and a threaded shank portion 14. A mounting fixture 18 is provided for rigidly coupling said base portion to the mounting interface of a supporting structure with the axis of the screw perpendicular thereto. A traveling ball nut 40 threaded on the power screw 12 is formed with an external annular arcuate surface 41 configured in the form of a spherical segment and enclosed by a ball nut housing 50 with a conforming arcuate surface 51 for permitting gimballed motion thereon. The ball nut housing 50 is provided with a mounting surface 53a which is positionable in cooperable engagement with the mounting interface of a primary structure to be coupled to said supporting structure.