Our plan does not stop at the arrival of the first four. They will be followed by more groups, spaced every two years, which will eventually lead to the base becoming a small village. As a settlement, they will be able to produce more and more on their own. At first this will be limited to provisions, oxygen and water, but will soon expand to everything they might need: solar panels, new living quarters and plastic components. The settlement will develop as those inhabiting it become architects of their own environment.
In time a second base could be built at a different location on Mars. Mars has the same area of land as the Earth, because Mars has no oceans. Really, those first four in 2023 are just the beginning of our adventure.