The tunnel entrance and exit can connect power and Life Support grids at different locations and different elevations. Rovers can travel along the tunnels to reach places they otherwise couldn't.

The cost is for the entire Tunnel, which includes both placed ends. In order to build the Tunnel, players place one end at the desired starting point and the other end at the desired terminus. The drones will build both ends simultaneously, so only the starting piece has to be within range.