One century or two passed since the launch of Sputnik. These first three steps will be followed by many others …

The horizon joins the speculations of science fiction, between uncertain, possible, and probable futures. Maybe "cathedrals of the third millennium will be large artificial hollow planets, hosting complete and controlled ecosystems", some of them crossing space to reach other stellar systems ; maybe "terraformation" will totally modify the surface of Mars, to reproduce the terrestrial environment in another part of the solar system; maybe "space elevators” of hundreds of thousands kilometers length will connect the sky and the ground, like an immense material link with space...

A future is to be drawn. An archipelago is to be built. On the eve of the space era, Gaston Berger said: "tomorrow will not be like yesterday.
It will be new, and will depend on us. It is less to discover than to invent".