This paper describes a five-degree-of-freedom mount developed by AMOS to perform the integration of the large aspheric mirror into the mechanical structure of the military satellite HELIOS. This mirror mount is computer controlled, class 100 clean environment compatible and can be used in rough vacuum (10-1 mbar). Because of the specifications, dynamic analyses using finite element (FEM) method were necessary during the design phase. The final mirror mount is about 1.5 m high, 1.7 m long and 1.1 m across for a weight of about 700 kg. It is able to rotate the mirror around its vertex with amplitudes of +/- 1 degree(s) around the horizontal and vertical axes with resolution and repeatability better than 2'.