Elon Musk argues that we must put a million people on Mars if we are to ensure that humanity has a future

We will need to harness the spirit that moved our own species to trek into new continents, so that our recent ancestors could trickle out to islands and archipelagos, before crossing whole oceans, on their way to the very ends of this Earth. We will need to set out for new planets and eventually, new stars.

Impossible doesn't exists in Elon's vocabulary.