We are doing precisely what we need to do to send humans to Mars, Dr James Garvin, Nasa’s senior Mars scientist, told BBC News Online. Dr Garvin is a researcher with an impressive track record in exploring the Red Planet and he is excited and inspired by the discovery of vast underground reservoirs on Mars. Scientists have discovered there is so much ice beneath the surface in the polar regions of Mars that if it were to melt it would deluge the planet. But where does this discovery fit in with the long-term exploration of the Red Planet, and what are the prospects of sending humans to Mars?