ECM received in May 2014 from OHB, Germany the contract for the design, fabrication, test and qualification of the Star Tracker Assembly Bracket for the next generation weather satellite (MTG - Meteosat Third Generation), developed by ESA and operated finally by EUMETSAT. In December 2018 ECM delivered the last two Flight models fully integrated and tested to OHB, Bremen. This project was for ECM a big challenge being for the first-time prime contractor of a small subsystem consisting of an assembly of metal components associated to our HB-Cesic® bracket structure. In this paper we will report about the successful manufacturing process of seven flight models including STM Model for qualification in a rather short time frame of less than 2 years after CDR. This paper is focused on the successful manufacturing and precision machining of these complex light-weighted HB-Cesic® structures with low tolerance requirements to demonstrate ECMs capability of fabricating such Star Tracker Assembly Bracket subsystems.