The Random Positioning Machine as Space analog - Mechanical and biological Characterization and Validation

The following thesis discusses a possible method of studying microgravity effects using a microgravity simulator: the Random Positioning Machine. Furthermore, the study intended to verify the RPM performance on both a biological and mechanical level. The RPM was tested to ensure that it accurately simulated a microgravity environment appropriate for planarians and in order to find the characteristics of the machine that would best simulate this condition. The study and validation of the Random Positioning Machine are crucial for its continued use. It establishes the RPM as a reliable microgravity simulator, providing a scientific foundation for future research and rigorous investigation in the field of microgravity. The Random Positioning Machines represent one of the most widely used laboratory tools to simulate microgravity, it is a device consisting of two frames, thus with two axes of rotation perpendicular to each other, which rotate at a constant speed by randomly varying the direction of rotation. In order to obtain reliable results, however, it is essential to use the RPM appropriately and to understand whether and in what cases such a device really offers a reliable analog of microgravity, we will therefore attempt to validate the RPM through mathematical tools and by analyzing data collected from experiments performed on planarians. In this study, planarians (scientific name: Dugesia spp.) were employed as the model organisms for experimental investigations, they are a wide group of flatworms, most of which live in aquatic environments and can reach the length of a few dozen milliliters. These animals are well known for their extraordinary capability to heal and regenerate themselves. We conducted the experiment by placing one animal in the lab tube and placing six tubes on the RPM, running the machine at various speeds for varying periods of time, and then observing the results by recording animal behavior for 300 seconds. In conducting this research, the mechanical aspects were primarily undertaken individually, with minimal external assistance. The author independently focused on the mechanical characterization and validation of the Random Positioning Machine. Conversely, for the biological component, the author sought guidance from their tutor at the International Space University due to their limited knowledge in the area. The tutor provided valuable support and expertise, aiding in the design and execution of the biological experiments involving planarians. The findings of this study reveal that certain rotational speeds and exposure time did not yield favorable outcomes. The experimental results indicate that specific combinations of speed and time intervals were not conducive to achieving the desired objectives or producing satisfactory results. These observations emphasize the importance of carefully selecting the appropriate parameters; following this, the pilot experiments were skimmed at three different speeds and over two different time. Positive results have been achieved regarding mechanical validation while from the biological point of view more studies are certainly needed and to draw more certain conclusions it is necessary to conduct experiments in a real microgravity environment, e.g. on the ISS.