Large-scale industrial and engineering heritage sites are increasingly threatened by obsolescence, restricted access, and demolition, making timely digital documentation essential for preserving their spatial and technical knowledge. This paper presents a multi-sensor documentation campaign conducted at a late twentieth-century space engineering training facility shortly before its demolition. The site’s scale, curved geometry, dense infrastructure, confined spaces, and variable environmental conditions posed significant challenges for data acquisition and processing. A hybrid workflow was developed integrating terrestrial laser scanning (TLS), immersive 360-degree capture, and targeted indoor drone-based image acquisition. TLS formed the metric backbone of the documentation, while immersive capture supported spatial navigation and contextual understanding. Drone imagery was selectively used to enhance visualization of inaccessible interior areas rather than for full photogrammetric reconstruction, due to site-specific limitations. Results demonstrate that no single technology was sufficient to address the combined geometric and operational constraints of the site. Instead, a coordinated multi-sensor approach enabled the creation of a comprehensive digital record that balances accuracy, completeness, and interpretability. The study highlights both methodological limitations and practical solutions relevant to documenting complex space heritage under time-sensitive and constrained conditions. The workflow presented is transferable to other large-scale engineering heritage sites facing similar risks and challenges.