The thesis discusses the design of the secondary mirror support structure for the deployable space telescope. In the thesis the entire support system is considered, including system layout and mirror interface. A selection of hinge concepts were identified and final concepts were selected in trade-offs. The mid hinge was selected to be an integral slotted hinge, while the top and root hinges were selected to be CORE hinges. The concepts for the root and top hinges were worked out in detail to a point that the hinges can be produced and tested. Thermal and launch loads were considered during the detailed design of these hinges. Furthermore, it was investigated what the effect of adding ribbons to the structure was on the response of the system to harmonic disturbances. The results of this thesis can be used to produce a breadboard for testing the secondary mirror support structure, and as a baseline for further design work on the secondary mirror support structure.