Documentary science series.
Chris McKay is a Nasa scientist who believes it will be possible to 'terraform' Mars to create a new atmosphere and add water and plants to make the planet habitable. "The notion of going to a barren planet and bringing life there, that's a creative act and it's part of what I think it means to be human," he says.
Changing the red planet to the green planet would be the greatest engineering challenge ever. But is it possible - or is it just science fiction?
Transcript: send £2.00 cheque to [address removed]