During the launch environment, dynamic loads are transmitted to satellites located within the payload fairing, leading to the failures of its structure. Therefore, the analysis of natural frequency can be utilized to observe the response of the main structure and avoid interaction with launch vehicle dynamics. In this paper, the structural analysis for Thai Space Consortium (TSC) satellite is presented through the concept of Low-Earth Orbit Earth observation satellite. The Falcon 9 launch vehicle environment is applied as a primary reference. First, the different designs of the small satellite structure consist of horizontal, and Modular layout are created. Second, the numerical simulation using the Finite Element Model (FEM) is accomplished to observe the structural analyses especially, the failure stress factor. The quasi-static and displacement are considered. Then, the vibration analysis is conducted for each load, such as natural frequency responses, sine specification, and random load to meet the launcher's requirements. The comparison of two designs is validated. The results show that the static load and the vibration are acceptable and not critical to the satellite's main structure.