59 SYSTEMS: STRUCTURE AND MECHANISMS—THE INTERNATIONAL SPACE STATION’S SKELETON CHAPTER 3 (Figure 29). These panels, held in place by a few fasteners (that sometimes get stuck and need to be “convinced” to open), serve to close out open spaces and provide a good aesthetic for each module. Conclusion The structures of the ISS provide the critical role of creating a stable platform for the completion of the space station’s mission of scientific research and preparation for exploration beyond Earth orbit. The buildup of the ISS over time and numerous international launches created both unique challenges and unique opportunities that have led to a diverse and highly capable structure. The remaining chapters will explain how crew and ground teams have used the capabilities provided by these structures to ensure the crews remain safe in their orbital home and are able to perform their missions.