The expansion of "U-Tu" is remarkably simple, merely requiring the addition of nearly identical compartment modules atop the original Core Module, allowing the space station's permanent crew capacity to increase to around 10 people, and its operational mass to surge to over 200 tons.
As for the construction of the Lunar Residential Area, there was a debate between 3D printing and local manufacturing, but initially sending up ready-made habitat modules was the most convenient.
Eight standard modules, each weighing about 20 tons and measuring 14*7*5 meters, could be arranged internally to serve various functions. They would be divided into four living modules, one service module, one agriculture module, and two transitional/equipment modules.
The four living modules, connected in a cross layout via a node module, would provide a total living area of 300 square meters and 12 rooms, sufficient to accommodate 20 astronauts.
