The moon - a source of helium-3?Man first walked on the moon on 20 July 1969 and last set foot on the moon on 14 December 1972. Recently there has been increased interest in returning to the moon and one of the reasons for this is the potential to mine helium-3 as a future source of energy back on Earth.The first hydrogen bomb tested in 1952 involved the reaction between deuterium and tritium (known as “D-T fusion”).