Above: Astronaut Thomas Pesquet floats next to the airlock inside the Japanese Experiment Module aboard the International Space Station, 7 December, 2016. Credit: Unattributed/NASA.
Industrialization is causing pollution and climate change which calls into question the future habitability of Earth (SP: 131). Following the catastrophic and systematic abuse of our planet, to simply leave Earth behind would be a neat liberation from a dying planet. However, for Virilio, the persistent myth of inhabitable worlds beyond Earth is a corrosive fantasy in that it tends to keep in play the idea that when Earth is "all used up" humanity will simply move on to another celestial body. (Most likely to once again remorseless strip it of its resources and eventually render it toxic, etc.)
In the context of the ongoing destruction of the planet, the popular dream of humans leaving the home planet and travelling to another--"going away to the stars"--must be urgently challenged as it is as nothing but dangerous illusion (VW: 88). Any such "exodus of humanity" would be no more than a "great leap into the void of celestial nothingness (CP: 114)."
This exodus idea is a fabrication which tends to be incited by NASA with its space missions such as the International Space Station (ISS), and the Mars Rover. The technology of rockets with sufficient thrust to reach "escape velocity" from the Earth's gravitational force "appear to offer us a way out," but this idea of an escape-route is deceptive since all that lies beyond is empty darkness (CD: 150). The ISS crews do stay for several months-at-a-time aboard the Earth-orbiting station, and this tends to encourage the perception that humans will, in the future, live apart from or away from the Earth. For Virilio it is essential that popular opinion recalibrates towards the bitter reality: humanity and the Earth are indivisible--to be human is to be alive and living on Earth; there has been and will not be any other existence possible.
Only once the belief in some sort of escape--of moving house en masse--is definitively quashed will the possibility emerge for a far greater care and respect for our unique celestial body. Ecological catastrophe can only be averted if humans en masse accept that there is but one planet and therefore it must be esteemed and maintained accordingly. Humans cannot quit the Earth: any such belief is irrational and in fact delusional: candidate planets with a potentially breathable atmospheres are hundreds of light-years away; equally, schemes which propose to create an artificial oxygen rich atmosphere surrounding another planet are untenable and ludicrous. (To keep only five scientists alive on the ISS costs around $125 million per year with at least fifty full-time staff on the ground at ISS mission control.)
The distressing truth is that, for better or worse, Earth is our ultimate-and-unique "territorial body," it is non-negotiable in that without it humans would not/could not exist "if there is no land there are no humans (CD: 102)." Hence we need to "come back to the Earth (IB: 8)."