Let’s suppose the surface of the Earth is no longer habitable. Or there are too many of us.
But this is not so important anymore because the only thing we need is gravity.
The world has changed.
The surface of planet Earth is no longer habitable — it is completely polluted.
Mars terraformation takes time while large-scale explosions forming a suitable atmosphere. Therefore, the inhabitants of the earth are forced to create colonies in the sky in anticipation of being sent to a new home.
Life capsules have everything you need to survive. Technologies have made it possible to collect and purify water, as well as to grow all kinds of necessary plants in artificially created conditions.