The Moon It seems like an inhospitable and extraordinarily dry place, but within the framework of our return to the satellite, the various space agencies intensify the search for water on its surface.
In this context, the analysis of the samples collected in the Oceanus Procellarum for the mission Chang’e-5 of the Chinese Space Agency estimates that the lunar surface can harbor between 30 and 30 billion tons of the liquid element. Such a discovery could not only be used as a source of energy but also to supply water to future lunar bases without the need to load it from Earth in expensive supply missions.
something that seemed impossible
All Solar System bodies larger than 1000 km in diameter are defined as planetary bodies. Not all of them have an atmosphere, as occurs on the Moon, and their absence exposes them to the onslaught of asteroids, comets and their fragments that, progressively and over the last 4.5 billion years, have dug craters on their surfaces. These projectiles hammer them constantly and the process is very violent since they impact at hypervelocity.
The resulting energies can vaporize the projectile itself and part of the surface rocks, excavating craters and creating impact plumes for a few moments, in which the materials will even reach temperatures where they go into the vapor phase. In this process, exogenous materials are also implanted since a type of rock called impact breccias is created: the materials of the body and the projectile are mixed and compacted at high pressure.
The outlook does not look rosy for the survival of volatile substances, that is, those capable of melting at relatively low temperatures. In fact, the presence of water on the lunar surface in significant quantities was a great unknown. Until now.
The discovery of the Chinese mission Chang’e-5
Knowing all of the above, we could think that the surfaces of planetary bodies that do not have an atmosphere, such as Mercury, the Moon or the Asteroid Vesta , they should lack water, but we would be wrong. This is how it corroborates a new study from the Chinese Academy of Sciences which, based on the regolith samples returned by the Chinese Chang’e-5 mission, has just shown that certain glass spherules, which are produced after these impacts with meteoroids, are particularly capable of absorbing very significant amounts of water.
In fact, the surfaces of these spherules are continuously bathed by hydrogen and other chemical elements that make up the solar wind, a kind of breath that our star continuously gives off and that expands around it, bathing the planetary bodies that surround it. .
The chemical elements that arrive with the solar wind interact with the glassy spherules and, on their surface, water is formed that is retained through a diffusion process in its mineral structure.
In fact, the silicate crystals are particularly exposed to aqueous alterationa process that degrades them and that also seems important in those environments exposed to spatial processing (space weathering).
Millions of tons of water on the Moon
In total, taking into account that these spherules produced by impact extend in the regolith along the entire lunar surface, they represent a not insignificant amount of stored water. In fact, It is estimated that in total it can range between 30 and 30,000 million tonsdepending on the number and storage capacity they have, something that seems to be subject to variations in their composition.
As if that were not enough, the hydrated chondritic materials that reach our natural satellite are also implanted in the regolith that forms its surface. In fact, groups of hydrated carbonaceous chondrites have implanted their components on the lunar surface over the eons, enriching the lunar regolith and the so-called impact breccias. Those projectiles that arrive continuously contain hydrated minerals: phyllosilicates, oxides and carbonates that they are the result of the aqueous alteration of asteroids that were soaked in water in the earliest times, tens of millions of years before the Earth had just formed.
Missions in search of water and other resources
It should come as no surprise that recent missions have made use of state-of-the-art instrumentation to identify water-rich regions of the Moon. That is the case of the Russian instrument Lunar Exploration Neutron Detector (LEND) it was designed for interplanetary mission Lunar Reconnaissance Orbiter 2009 (LRO) with which NASA explored in detail the future lunar landing areas at the lunar south pole.
The basis of this ingenious instrument is that neutrons bounce from atom to atom like billiard balls, losing energy with each collision. Some of these neutrons escape into space, where LEND detects them.
However, those areas of the lunar regolith that contain hydrogen reduce the number of escaping neutrons. Thus, in order to map possible ice deposits, scientists use this type of neutron detector.
The results obtained by the probes used to date point to the existence of frozen water deposits in those craters and regions permanently shielded from sunlight.
We can get an idea of the relevance of finding water reserves on the Moon but also of the intrinsic difficulties behind its extraction and use. Precisely from the CSIC we work on these resource reuse techniques on siteknown as ISRU.
Understanding in great detail the nature and properties of the materials that make up the lunar surface is key to overcoming the technological difficulties involved in being able to use them to address new challenges. Thus We proposed the use of a rover within the framework of the Artemisa missions to undertake a program to search for resources for immediate use.
In fact, the development of ISRU techniques will be the first step to be taken in future manned sample return missions if you want to lower their costs, increasing the feasibility of using the Moon as a gateway to other worlds. In fact, that’s what the call plans Lunar Gatewaycurrently under construction.
In this scenario that, today, seems futuristic, the liquid element will be essential to generate energy or even, if we manage to develop adequate purification systems, they could be commonly used by astronauts or to terraform environments close to future lunar bases. .
Josep M. Trigo RodríguezPrincipal Investigator of the Meteorites, Minor Bodies and Planetary Sciences Group, Institute of Space Sciences (ICE – CSIC)
This article was originally published on The Conversation. read the original.
