Modular Building Block Truss Structures for In-Space and Lunar Applications

Abstract

Given recent advancements in space technology and the growing space economy, the need for large space structures has increased. Significant capacity for power, payload storage, and propulsion capabilities is required for several potential lunar and in-space activities. Examples include long-duration space exploration, in-space solar farms, and the construction of lunar structures. For activities such as these to be feasible, modular truss structures must exist to provide a structural framework capable of satisfying the requirements for power, payloads, propulsion, and expansion potential. An example of a structural framework is the Integrated Truss Structure (ITS) for the ISS. The ITS consists of several truss segments, which include attachment points for external payloads such as solar arrays. The freedom given by the ITS has allowed many repairs and upgrades for the ISS, extending its operational lifespan. This thesis explores the development of modular building-block truss structures designed for in space and lunar applications. The truss modules utilize probe and cone docking adapters to secure connection between modules during assembly. The docking adapters use modified geometry to correct for rotational and translational misalignment during soft capture. Shape Memory Alloy (SMA) springs act as actuators to lock and unlock latches, which secure the adapters during hard capture. Further, the docking adapter permits power transfer. The use of the docking adapters enables the truss modules to expand in any direction and create attachment points for payloads. The development of the docking adapters, including the characterization of the SMA springs used, is presented and discussed. Structural analysis was performed in Ansys to assess various truss configurations, materials, and environments. Physical testing was done on a prototype truss module. The physical and simulation results were compared to determine the optimal truss structure. Several applications using the chosen modular truss structures are described, including the power, payload, and propulsion capabilities of the truss modules. Potential assembly operations, including autonomous and manual assembly, are detailed with construction plans and concepts of operations for each application.