Integration of Thin-Film Solar Cells with Tensioned Kapton Substrates for Space Solar Power Applications

Caltech’s Space Solar Power Project proposes a modular, ultra-lightweight photovoltaic array that can be deployed in orbit to harvest solar energy and beam it to Earth. A key challenge in this architecture is reliably integrating thin-film solar cells onto Kapton substrates that must remain lightweight, flexible, thermally stable, and wrinkle-free under pre-tension. My senior thesis addresses this challenge through the design and fabrication of a tension-controlled test stand capable of evaluating Kapton adhesion, mechanical behavior, and thermal response. The system uses a 13" × 13" t-slotted aluminum frame, laser-cut aluminum tabs, and adjustable turnbuckles to generate uniform biaxial tension on Kapton film bonded to representative thin-film layers.
I am experimentally studying multiple bonding techniques, including epoxies, polyimide adhesive films, and space-grade silicones, under strict mass constraints (<10 g/m²). By combining controlled tensioning, surface treatments, and eventual thermal cycling, I analyze adhesion strength, wrinkle formation, and delamination patterns. The project integrates image-based deformation tracking, basic analytical modeling of tension and shear stress, and preliminary FEA to evaluate load distribution across the film. Ultimately, this work provides experimental methods and comparative data that support material integration strategies for the SSPP deployable photovoltaic modules, contributing to the feasibility of large-scale, space-based energy infrastructure. My first term report for my senior thesis can be found here.