Okay, anticlimactic news first, it was a big bare cargo receiving area. The drones circled, catching video of discolored stone walls with metal scaffolding to support the hatch mechanicals and various cables. No feed markers, but a few signs I translated via Thiago’s language module; all were cautions about the proximity to the engines and possible damage to unshielded sensor equipment. There were two dark openings leading off somewhere, probably access tunnels. Also more heavy equipment rails built onto the natural rock floor, as well as a big lift platform stored vertically up against one wall. Cargo transportation using permanently installed rails was usually cheaper, more power efficient, common for systems you’d only need while the engines were being constructed.