One of the big questions about any future human endeavour into deep space is how are we going to keep them hydrated, fed and running on a full tank of fuel. Unless the modern-day pioneers take everything with them – unlikely with such enormous costs involve in boosting anything out of our atmosphere – mineral extraction looks to become crucial for moon or Mars missions.A handful of firms are looking at space mining and, in particular, water extraction from planets and floating rockets to serve interplanetary missions. Space flight firms are developing the capacity to use hydrogen (found in water) as space fuel, saying it could reduce mission costs by 95%.iSpace, a Japanese company founded in 2013, is looking at how 4kg robotic lunar rovers could be used to prospect for resources on the moon. And US-based firm Planetary Resources, run by a former Nasa flight director, wants to mine asteroids found relatively near Earth.