FEASIBILITY ANALYSIS ON THE USE OF WOOD-BASED STRUCTURES IN SATELLITES (Masterarbeit)

Abstract

The increasing number of space activities, marked by the proliferation of satellites from private entities such as SpaceX, raises concerns about the growing threat of space debris. To address this issue, authoritative bodies like the European Space Agency (ESA) and the Committee on the Peaceful Uses of Outer Space have implemented stringent Space Debris Mitigation Guidelines to prevent the pollution of near-Earth orbits. These guidelines include a maximum grace period of five years for satellites in near-Earth orbits to deorbit after the end of their lifetime, thereby actively preventing a cascading effect known as the Kessler syndrome. With the anticipated increase in space activities and launch attempts in the coming years, the impact of deorbiting satellites into Earth’s atmosphere plays a crucial role. Currently, most satellite structures and upper stages are composed of aluminum alloys and other metals, which could negatively affect terrestrial ecosystems as the number of deorbiting satellites increases. At the DLR Institute of Structures and Design, efforts are being made to address the environmental impact on Earth’s atmosphere by researching eco-friendlier materials for spacecraft structures. This thesis explores the potential use of wood-based structures for space applications, focusing on the harsh environmental challenges that primary structures must withstand during launch and orbit phase. The study begins with presenting the relevant theoretical background, followed by a description of state-of-the-art technologies. Three different-sized satellite structures are assessed for their mechanical compliance in withstanding launch loads using wooden structures. Based on numerical simulations of a 3U CubeSat, FLP, and a simplified large-sized model based on the overall mass of Sentinel 2A, specific design concepts are proposed for further investigation. Mechanical characterization, including 4-Point-Bending Tests (4PBT) and Compression Tests (CT), is conducted on the proposed and manually manufactured concepts. The study significantly assesses the harsh environmental conditions in space through experimental, numerical, and analytical simulations, covering thermal compliance, outgassing, radiation, electrical compliance, and the impact of atomic oxygen. Finally, proposed satellite design concepts for wooden primary structures are presented for each of the three analyzed satellite sizes, in accordance with the findings of this work.