Moon bases for spacemen was a theme of 1960s science fiction, perhaps best remembered in the series Space 1999, where the unfortunate Moon- dwellers were blasted into a reluctant voyage through outer space at a pace that shamelessly defied the laws of physics.
Thirteen years post 1999, we are still gradually inching closer to colonising other parts of our solar system. The logical place for the first non-Terrestrial permanent residence would be underground, where there is some protection from cosmic rays and meteorite impacts.
Luckily for us, possible sites already exist on the Moon and Mars: deep tunnels of as yet unexplained origin. In 2009, the Japanese satellite SELENE photographed just such a place on the Moon. A tunnel, approximately 65 metres wide and at 80 metres deep which lies in the Marius Hill region.
Technology to explore these tunnels is currently under development. William Whittaker, a roboticist at Carnegie Melton University in Pittsburgh, has invented a rover that can explore underground sites, and has signed a contract with SpaceX to carry his equipment to the Moon. SpaceX is competing for the $20 million Google Lunar X prize, to land a vehicle on the Moon, move it 500 metres and send back data.
It might not be Space 1999 just yet, but it is a step closer.