Water has long been the limiting factor for humans in space. But now, NASA is developing a rover that can make water on the Moon. Such a capability will be necessary for any serious attempt at the permanent settlement of Mars, or any other long-term space voyage. If successful, it will inaugurate a new, critical area in space exploration, where resources from other worlds can be harnessed and used.

Presently, everything we use in space is made on Earth. Consider the big, visible parts of human exploration of the solar system, rockets like the Space Launch System (SLS), under construction and set for its maiden voyage in 2018. There’s also the Orion capsule, tested previously and set to fly atop SLS (without astronauts). Then there’s work on habitats: Scientists are currently working on manufacturing artificial habitats for the International Space Station, but soon will be working on one for the Martian surface. A huge part of this kind of pioneering the solar system, however, concerns not just what we bring to other worlds, but what we leave behind. The Lunar Resource Prospector is the first big step in striking that balance.