NewSpace NewManufacturing - Injection Molding of Satellite Structures

Standardizing the interface between satellites and rockets lead to a sizeable rise in the number of launched and operational small satellites over the past two decades. By giving severe limits for the outer dimensions of satellites, the CubeSat Standard also brought a paradigm change in the development of satellite subsystems. As volume, available mass and available areas for solar cells became variables with fixed upper limits, manufacturing whole subsystems as commercial off-the-shelf became a viable option, as they fit most CubeSat missions. However, it did not lead to a change to mass production technologies yet. We propose the first mass-producible satellite structure, designed for injection molding based on the high-performance polymer polyether ether keton, better known as PEEK. PEEK is a traditional material for gliding surfaces and structural parts of spacecraft. Advances in injection molding already enabled mass-manufacturing with PEEK for medical devices and the automotive industry, which shall now be transferred to space applications. PEEK materials come with a wide range of expansion coefficients, including the range of aerospace aluminum, hence fulfilling all requirements for a CubeSat structure. The structure is designed to give the designers a maximum of flexibility, while ensuring a fast and simple integration. It already includes the prescribed inhibit-switches and necessary electronics. The simplicity of the integral design ensures a safe and reliable operation. Further advantages are the comparably low price, prototypes molded from any other polymers, including economic polymers for integration testing and show pieces, and the ability to produce high volumes of the structure on short notice. This paper describes the first prototype of the structure itself (sized to 1U), its mechanical interfaces and integration strategies for spacecraft using the structure. It details challenges in the design for injection molding as well as the material selection. It goes on with results and lessons learned from integration testing with the first prototypes of the structure and a PC/104 based electronics stack as well as back-plane-based electronics stacks. The injection molding tool and process are presented as well. The paper concludes with an outlook on the strategy for acceptance in the CubeSat Standard and our future work.