Abstract: A gyroscope mounting structure for use in a spacecraft attitude control system has ten control moment gyroscopes. The structure has a truss for supporting the gyroscopes. The truss has an axis of symmetry. Five front gyroscopes are axially spaced from five rear gyroscopes along the axis of symmetry. The front gyroscopes and the rear gyroscopes are peripherally spaced about the axis of symmetry at equal angular spacings. Each gyroscope has a gimbal axis which is disposed at substantially the same acute angle to the axis of symmetry. Each gimbal axis is disposed parallel to an adjacent reference line which passes through a common intersection point on the axis of symmetry. The truss has a front frame, a rear frame and chords connecting the frames. The truss has five front struts interspaced between the five front gyroscopes for support thereof. The truss also has five rear struts interspaced between the five rear gyroscopes for support thereof.