Ever since man began to observe the sky, he has been fascinated by the moon. In ancient times some cultures believed it was a God and up until today it is a subject in literature, arts and astronomy. But only in the recent decades we have begun to explore it at close range. In 1969 Neil Armstrong was the first human to put a foot on the ground of the moon. Thenceforward it has undergone intense scientific study and one of the most important questions was: is there water on the moon?

At first sight, this question sounds ridiculous. If we look at our celestial neighbor through a telescope we recognize it as a dry object which has no signs of water whatsoever: there are no oceans, no lakes and no clouds. So why should we assume that there is water? The answer is hidden deep inside the permanently shadowed craters at the moon’s polar regions and in lunar rocks. From your physics classes you will probably remember that water will evaporate as soon as there is no atmospheric pressure like it is true for the moon. However, if we enter those dark areas of the craters we will measure very cold temperatures at which water could persist as water ice. Furthermore water is a chemical compound that is formed out of hydrogen and oxygen. Thus it could also be chemically bound in rocks and minerals.

In the last decade, several satellites have orbited and even impacted on the moon to detect water or water related compounds on its surface. The collected data of those missions strongly suggests that indeed water (H2O) or hydroxides (-OH) exist there either as ice in dark craters or chemically bound in lunar rocks. Thus, if the data is correct this could enable us to built inhabitable moon bases which can produce or extract water in situ, i.e. astronauts won’t need to bring with them water from Earth in large and expensive space tankers.

Another big advantage of water on the moon would be the possibility of launching rockets from there into space as rocket fuel can be made from the elements hydrogen and oxygen. This would make manned missions to other planets like Mars or certain moons in the solar system much cheaper because lunar gravity is only one sixth of Earth’s gravity and hence the fuel consumption would be considerably less. Finally water is a vital condition for vegetation, i.e. in theory it would be possible to grow plants in pressurized greenhouses.

So there is possibly an amazing future ahead of us on the moon and beyond if we can make use of the water that we find there.