This thesis investigates the feasibility of a flat deployable two-membrane reflectarray antenna for Synthetic Aperture Radar missions. Reflectarrays offer advantages over traditional parabolic antennas in terms of weight, cost, and volume efficiency due to the possibility of having a flat shape. A spring-hinged panel design is proposed and evaluated through simulations of orbital thermal loads and deployment dynamics. Solutions such as thermal coatings or additional support are also investigated.