The purpose of this research is design of solar panels for a satellite which put in to geostationary orbit considering siutable reliability. The process of solar panel design is conducted according to the Design Structure Matrix (DSM) method. In this regard, an initial plan, a subsequent design process improvement, and a final optimized design process are provided. The first level of designed mechanism product tree includes released mechanism, development mechanism, lock and rotation components. Given the importance of ensuring the proper operation of mechanisms in space and reported mission failures due to lack of mechanism’s operation, the reliability network of designed mechanism is constructed and the reliability of designed panel is calculated. The amount of achieved relaiability is then verified according to the mission and system engineering requirements. Nessecary changes are applied on initial design to achieve into the satisfactory reliability for whole solar mechanism. In this regard, the critical paths in reliability network which lead to reduced reliability are investigated, and improvement of the critical path are proposed, to the extend of increasing reliability by discarding redundant components for critical parts.