Space was once a byword for fantasy and wonder, but it has been firmly bought down to earth. The space industry today is rapidly expanding and diversifying into fields from mining to gaming, real estate and tourism. Over 600 new companies have entered the field since 2011
, with private investment rocketing past $1 billion
-- a new record. But as opportunities multiply, the competition is growing fiercer. Many of the new players will inevitably fail to launch. But some will push through the final frontier.