## 1 Introduction  
For decades, minisatellites have demonstrated their capability in complex missions and have made essential contributions to space science in multiple disciplines. Small satellites have attracted industrial attention due to their flexibility, rapid development, resilience, low cost, and risk tolerance in cutting-edge technology. Furthermore, because they have the ability to replace huge systems, they have altered the space industry in the satellite sector during the previous several years [1]. In the Small-Sat class, minisatellites have more available power, larger payload mass, and more capable radio systems that can transmit more data than the smaller satellite categories [2, 3]. It is common for minisatellites to include propulsive capabilities for orbit adjustments and orientation, encrypted communications, and fine pointing that are beyond the reach of smaller containerized platforms. Minisatellites are becoming increasingly important in low Earth orbit and Geostationary Equatorial Orbit (GEO) and are likely to have a more significant presence in deep space in the coming years [4]. In 2013, 247 CubeSats and 105 additional non-CubeSat small spacecraft weighing less than 50 kg were launched into orbit, accounting for less than 2% of the total mass sent into orbit across several years. In 2013, almost 60% of all spacecraft launched weighed less than 600 kg, with 83% weighing less than 200 kg and 37% being nanosatellites; 94% of the 1282 spacecraft launched in 2020 were tiny spacecraft having an overall mass of less than 600 kg, with 28% being under 200 kg and 9% being nanosatellites. Since 2013, the demand for small spacecraft has climbed by more than 30%, becoming the key source of space access for commercial, government, private, and academic entities [5]. A satellite is composed of several parts, which vary depending on the type of application and orbit. Two elements, however, are common to all satellites and are called payload and platform [6]. The platform is the part of the satellite that carries the payload and all its equipment in space. It is the vital part, as it keeps the rest of the satellite together and allocates power, propulsion, and data processing systems. The platform also contains devices that allow communication with terrestrial control stations. The primary structure, usually made of aluminum or carbon fibers, must be strong enough to survive unharmed by the inertial loads: the carrying of satellite mass, and during the launch the accelerations are up to 8 g [7]. In addition, it shall be stiff enough to separate the satellite's global dynamic behavior from launch system one and avoid the risk of destructive couplings among them. In fact, this coupling could impair the onboard item alignments/pointing and, in the worst cases, damage the structural integrity too [8]. Over the past decade, several commercial families of small satellites have been developed by providing the technological framework for launching systems with specific functions into orbit without worrying about technologies related to the launch, propulsion, flight, power supply and data links [9]. The Evolved Expendable Launch Vehicle (EELV) Secondary Payload Adapter (ESPA), which is a specific adapter for launching secondary payloads on orbital launch vehicles, was developed for small satellites [9]. Although it was originally developed for US military launches in the 2000s, the adapter design has become a de facto standard and is now also used for spaceflight missions on commercial missions as well. For example, multiple ESPA rings were used on SpaceX Falcon 9 [10]. Small satellites encompass a wide variety of miniature spacecraft, typically identified by their mass. NASA small spacecraft definitions (Small-Sat) [9] set the upper mass limit to 180 kg, which corresponded to the original ESPA secondary payload mass limit, and defined the following categories: Minisatellite 100-180 kg, Microsatellite 10-100 kg, Nanosatellite 1-10 kg, Picosatellite <1 kg, and CubeSat.