Using current technology, Mars could be colonised within decades, argues Adam Steltzner engineer at NASA's Jet Propulsion Laboratory, where he led the design of the Mars Curiosity "sky hook" landing system. Steltzner projects how humans might be able to make a home beyond the confines of the Earth, but questions the motivations for such an endeavour. He argues, that a lot of people are attracted to the idea of colonising Mars because we are going to overpopulate or pollute this...