Some of the most convincing proof yet for the presence of water on the moon has been collected by researchers, and it is believed that this source of water can be relatively accessible. This can be quite implicative for the future of space missions. The moon was thought to be dry, right up to the 1990s, when spacecrafts orbiting the moon discovered detected traces of ice in large and inaccessible craters at the poles of the moon. In 2009, imaging spectrometers on India’s Chandrayaan-1 spacecraft observed signatures consistent with water in light reflected off the surface of the moon. However, the limitation in technology rendered it difficult to determine if this are H2O (water) or hydroxyl molecules (consisting of one atom of oxygen and one atom of hydrogen).
Casey Honniball and colleagues from Nasa’s ASA Goddard Space Flight Center in Maryland, USA found a chemical signature that is distinctly H2O by analyzing the wavelengths of sunlight bouncing off the moon’s surface via data collected from the Stratospheric Observatory for Infrared Astronomy (Sofia). They discovered water at the high latitudes near the south pole of the moon, in abundances of around 100 to 400 parts per million H2O. According to Mahesh Anand, Professor of Planetary Science and Discovery, Open University, Milton Keynes, the abundance of H2O discovered was quite a lot, “as much as is dissolved in the lava flowing out of the Earth’s mid-ocean ridges, which could be harvested to make liquid water under the right temperature and pressure conditions”.
For potential lunar missions, the presence of water on the moon has implications since it could be processed and used for drinking; divided into hydrogen and oxygen for use as a spacecraft propellant; and it could be used for ventilation with oxygen. Water in outer space is a very valuable commodity. It is, however, a risky endeavour to try to extract water from dark, steep-walled craters where temperatures rarely rise above -230 ℃, yet this is where the majority of the frozen water is assumed to be at.
Ian Crawford, Professor of Planetary Science and Astrobiology, Birkbeck, University of London, stated that there is a possibility of extracting water if there is that much of water in the craters, because it indicates a wider coverage of water in more easily accessed parts of the moon that are in the presence of the sun.
There are remaining concerns, however. Firstly, there are doubts in which form the water exists in. It could be in the form of tiny ice crystals distributed among the lunar soil, which would be easier to extract, in contrast with if it is dissolved within lunar glass, which could be complicated to extract. Another issue is the coverage of the recently verified source of water extends. If it is just a few microns or millimetres above the soil, then it is functionally negligible, but still relevant in terms of how it came to be there. Thus, the only way to be sure is to go to the moon and drill. The Artemis project of Nasa hopes to send a male and female astronaut to the moon by 2024, and there is a robotic drill in the works to obtain samples of lunar soil from up to 1 meter for the Russian space mission planned in 2025.
There is also the question of where to dig. There are suggestions of digging in the more permanently shadowed areas of the moon as the water there is more protected from the rays of the sun. These surfaces may be more abundant than originally thought, as shown by Paul Hayne and colleagues at the University of Colorado at Boulder, who plotted the distribution of smaller craters and regions of rugged terrain using photographs from the Lunar Reconnaissance Orbiter and determined that about 40,000 km2 of the lunar surface has the potential to store water. According to Professor Hayne, “The emphasis should be moved away from the handful of well-known broad craters and onto the plethora of possible landing sites that our analysis shows, with billions of possible water reserves spread across the polar regions”.
While this is an amazing discovery, people are not going to fly off to colonize the moon anytime soon. It may be a good call to check on our own natural sources of water and preserve them sustainably. Selangor, for instance, has been plagued by regular water cuts due to “pollution”. It must be kept in mind that if water sources on Earth cannot be sustained properly, what hope is there that water sources from other celestial bodies may be able to sustain us as well?