Colonising Mars: Is Elon Musk being overly ambitious?

Elon Musk, the founder and chief executive officer of SpaceX and Tesla, has outlined ambitious plans to colonise Mars. The blueprint, which is due for “major changes”, glosses over multiple mammoth issues. But it still sharpens the focus on what is often dismissed as science fiction. Mr Musk envisages setting up a city on Mars with a population of one million, and all amenities, including “pizza parlours and iron foundries”. Mars is more suitable for habitation than any other environment we can reach. The fourth planet has a day of 24 hours and 40 minutes, it has some atmosphere, and