These units are very large. The inner dimensions of the reactor silo are 27 m high, by 9 m in diameter, with a capacity of 1350 cubic meters. The mirrors focus 1400 m2 of sunlight on the heat pipe travelling through their focal point and then coiling through the interior of the silo. There is also a tank where water is condensed, and a radiator that cools the steam coming into that tank. The reactor silo is filled before dawn and emptied at sunset by autonomous rovers.
As the town is sited at Lalande Crater, 4.5 degrees S, the mirrors don’t need to track on 2 axes and can simply track around a north-south axis, with appropriate spacing to account for where the reflected light ends up.
Reference schematic from Space Resources Vol 3 – Materials