# Research on Design, Simulation, and Experiment of Separation Mechanism for Micro-Nano Satellites
## 1 Introduction  
The development of micro-electro-mechanical and micro-nano technology has caused a reduction in the size of optical, mechanical, electrical, and other equipment. At the end of the twentieth century, there was a boom in research on small satellites, and their application has grown rapidly [1, 2, 3, 4, 5, 6]. Due to their low cost, modularity, and standardization, micro-nano satellites such as picosatellites are acquiring much more attention in the aerospace field [7, 8, 9]. Numerous micro-nano satellites working in unison could be used for formation flying, establishing large load platforms, and other tasks in the future [10, 11, 12, 13, 14, 15, 16]. However, unlike large satellites, micro-nano satellites have a limited internal volume, making the high-performance shock and vibration damping systems impractical. Thus, the shock and vibration generated by the separation mechanism for micro-nano satellites should be strictly limited. This circumstance motivates the development of a non-explosive separation mechanism for the release and separation of micro-nano satellites [17, 18, 19, 20, 21, 22, 23, 24, 25, 26]. To launch numerous micro-nano satellites at the same time and release them according to requirements, a great deal of research has been conducted and some remarkable achievements have been made by many countries regarding the separation mechanism used for carrying and releasing satellites. The P-POD (Poly Picosatellite Orbital Deployer) was developed by the California Institute of Technology and Stanford University. Three generationsof P-POD have been developed so far: P-PODMKI, P-POD-MKII, and P-POD-MKIII [27; 28]. The XPOD family is a custom-made nanosatellite separation system designed and built at the Space Flight Laboratory of the University of Toronto, UTIAS. Its purpose is to secure the satellite during the extreme conditions of the launch environment. In addition, it serves as the interface between the satellite and the launch vehicle, and it deploys the satellite once it reaches the desired orbit [29]. The J-SSOD (JEM Small Satellite Orbital Deployer) was developed by the Japan Space Agency. This deployer could carry three standard picosatellites and release all three picosatellites at once via springs [30]. The Space Research Centre of the Polish Academy of Sciences together with Astronika company have developed an Orbital Deployer called DRAGON for ejection of the Polish scientific nanosatellite BRITE-PL Heweliusz. The device has three unique mechanisms including an adopted and scaled lock and release mechanism from the ESA Rosetta mission MUPUS instrument [31]. The MASCOT separation mechanism was developed by the German Aerospace Center. The mechanism was compared with other existing deployment systems and its performance was verified with two independent analysis methods using actual flight data taken during the ultimate flight activation event, which initiated the successful delivery and surface operation of the MASCOT asteroid lander [21]. To satisfy additional requirements for picosatellites, those deployers named SPL (Single Picosatellite Launcher) [32; 33; 34], RAFT (one picosatellite's name), and GNB (Generic Nanosatellite Bus) were developed by Germany, the USA, and Canada, respectively [31; 33; 35]. In summary, the separation mechanism serves as a vital interface between the satellite and the launch vehicle. However, it should not jeopardize the success of the primary spacecraft or launch vehicle. Numerous modern nanosatellite deployers now support nanosatellites of varying sizes, multiples, or swarms [33]. On the other hand, these separation mechanisms are typically used to launch 1U-3U experimental CubeSats. The satellites have a simple structure, a single function, and only a few protrusions on their surface, and the mass ratio of the satellite to the separation mechanism is extremely high, usually around 1, which increases the launch cost.