Almost forty years since an American first walked on the Moon, NASA has launched two spacecraft on missions that will help pave the way for a return to the lunar surface.An Atlas rocket roared out of Cape Canaveral carrying both pay loads. The first will enter a low polar orbit around the Moon mapping the surface in unprecedented detail, and analysing mineral composition and temperature conditions. The second mission will look for water on the Moon. A rocket will be fired at the lunar surface at a speed of 9,000 kilometres an hour. Sensors will then pass through the resulting cloud of dust and debris looking for traces of ice or water vapour. NASA hopes to send astronauts back to the Moon by 2020, which would be the first manned visit since 1972.