## 1 Introduction
### Literature Review
In general, the most important efficiency parameters, such as structural part count and number of assembly steps, which directly influence the level of complexity of the integration, have not been adequately addressed in either design. In fact, the complexity and the number of assembly steps has a direct relationship with the number of parts that exist. In addition, complexity can be a result of the mechanical interface method implemented. Therefore, it is important to have a platform where few parts and joints are needed for integration, with an assembly procedure easy to comprehend for someone who is not familiar with the tasks. Once a design is optimized to the point where it has few structural parts and subsystems with little interdependence, it is important to standardize the platform so that few design changes are required in subsequent developments. This can be achieved by defining the interface between the satellite subsystems and the structure. At the same time, it is  
Figure 3: (**a**) Exploded 3U model based on conventional interface methods and (**b**) connecting rods for mounting internal subassemblies. also important to allow some level of flexibility for subsystems or payloads with unique dimensions to fit into the structure without difficulty. The goal of this research is to develop a flexible standard efficient 3U STM (structure and thermal model) which is suitable for mass production applications. The design concept is developed as an STM for an ongoing 3U CubeSat project. Recalling the common conventional type of structure, which is made up of several structural frames, rods, and plates, it is important to address the associated challenges. Therefore, a slot-based structural design is proposed with a unique interface between the internal PCB and the structure. The following are design parameters defined to evaluate the design objective. The design goals:  
1. A reduction in the number of parts;
2. A reduction in complexity;
3. A reduction in the number of assembly steps;
4. To show the scalability of the design to the 1U CubeSat form factor;
5. To comply with all interface and launch requirements;
6. An adequate volume for the communication payload. These design goals are used as evaluation parameters to compare the new design concept against the existing traditional, conventional CubeSat structural designs. After this initial phase of design, an EM and FM models are currently being developed with further design optimization. In this study, the initial STM development, from concept design to manufacturing and testing, is explained. The purpose of the present paper is to develop a flexible and modular standard 3U CubeSat structure that is suitable for highly efficiency-demanding mass production applications. The novelty of this paper is the interface method used to mount the internal subsystems onto the slots, which provides a much lower part count with an easy assembly technique compared to the existing slot-type structural platforms. In addition, the slots are standardized to reduce the need for a change in the interface design of internal components, while at the same time facilitating the easy relocation of subsystems within the platform during the configuration definition phase. This paper consists of seven sections. The second section describes the conceptual development of the structural design. The suitability of the proposed design is evaluated against the existing structural platform in the third section. The assessment results are analyzed in the fourth section. The fifth and the final sections provide the conclusion and directions for future work.