Biospheres are inevitable
in the first phases of settlement
in Mars Mr Musk...
As is with possibly,
for the temporary measure.
Underground habitat.
Just until new structures
are built.
But. More importantly,
setting up ways to
mine the resource there
in the most automated ways
as much as possible.
(Possibly mining by laser)
Any sort of metals for construction.
Then giant CNC.
Refining and automating these
processes will create a city
on Mars quickly.