Building Moon base with electricity and provision which make the life of astronauts comfortable and safe seems like a plot of sci-fiction. But, is there any reality in it? BBC science correspondent Sue Nelson studied the colonialist plans of the world space agencies and found out if they had enough strength and resources to implement them on Moon colonization and beyond it.
Chinese breakthrough and US backlog
In January 2019, the China National Space Administration (CNSA) spoke about the upcoming stages of its successful lunar program to set up a moon base. After the first-ever soft landing of the Chang’e-4 automatic station on the far side of the moon, two subsequent missions are to deliver samples of lunar soil and rocks to Earth.
Then, Chang’e-7, which is scheduled to be launched in 2023, will begin research on the South Pole of the Moon, a region of particular interest because of the presence of water ice there.
China has already planned to send a robotic mission Chang’e-8 to the moon by 2027, which will conduct an experiment with 3D printing, using local resources for the construction of simple structures.
“We hope that Chang’e-8 will help test some technologies and do some exploring,” said CNSA deputy head Wu Yanhua.
China is not alone in an effort for the moon colonization: today, all the space powers are talking about it. And although to date, only Americans landed on the satellite, now they have to catch up with rivals in the moon race.
For a long time, NASA has not made public plans to create a lunar base, highlighting Mars as a priority. But in May 2019, the US space agency announced that American astronauts would land on the moon’s surface by 2024.
A few steps ahead, the European Space Agency (ESA) announced its intention to create a moon base in 2016. A year earlier, ESA CEO Jan Wörner introduced the concept Lunar Village, a non-profit project that brings together public and private investors, scientists, engineers, businessmen, architects, and artists. The task of like-minded people is to create and share infrastructure on the Moon for a variety of purposes: astronomical research, tourism, and geological exploration — the search for minerals that are lacked on Earth.
CNSA and NASA have already shown interest in the Moon Village project, and Jeff Bezos’s private aerospace company, Blue Origin, offered to develop a cargo ship with a payload of 4500 kg to implement it.
The Moon Village is not an official ESA program, but the agency’s plans are no less ambitious. So, the mapping of the lunar surface should be completed by 2030, then modules of the future moon base will be delivered to the selected location, their collection will be completed by 2042, and all life support systems, production facilities, and an observatory will be created by 2062.
But whatever organization wins the 21st-century lunar race, survival will be a key priority. Until now, people only have been on the Moon for three days, because is not the most hospitable place for a long stay.
Because of the rarefied atmosphere, the temperature difference on the surface of the moon is very high. So, at a sunflower point, it can heat up to +127° C and cool down to -173° C at night. The lunar day is 29.5 times longer than the earthly days, which dooms the colonialists for two weeks of daylight and two weeks of the night. This can be a problem for the accumulation and use of energy, so any new technology for the moon outpost must work in difficult conditions.
Several organizations, including Blue Origin, Airbus and ESA, recently created a moon-centric prize program known as “The Moon Race.”
It is already known that the development and testing of technologies are planned for 2021, and the Moon mission itself is set for 2024.
Prototypes of technologies selected for testing in a rarefied atmosphere of the moon will allow completing the mission in 5 years. In 2024, the Moon Race visionaries want to start building infrastructure, energy production, and growing plants.
How to build a house on the moon
Traveling into space is expensive. The heavier the payload of the launch vehicle, the more fuel is required and the higher the cost of the flight is. That is why, to create the infrastructure of the lunar base, economical visionaries prefer to use the available resources. For example, lava can be used as shelters leading to frozen water ice below the surface. Another plan is to build a base of lunar regolith – fine sand, which is similar to the volcanic sand on Earth.
Professor Mathias Sperl of the University of Cologne collaborates with the German space agency DLR, printing volcanic powder bricks. A regolith simulator forms the desired shape through a process called sintering when concentrated sunlight or lasers bind the material together.
Sperl said,” We’re not building Lego but we have interlocking bricks.” They are going to build something similar to Igloo using the bricks. It must be strong enough to withstand the pressure of a meter layer of regolith, which will protect the colonizers from cosmic radiation. But the construction of one building would be a very long process.
“It takes roughly five hours to make a brick,” said Sperl, “and you need 10,000 bricks for an igloo. It will take months.”
To speed up the process, more lenses will be required on the moon to store sunlight, and the construction itself to entrust the robots.
Survival on the moon
Since traces of water ice were found at the poles of the moon, lunar bases are most likely to appear in those places. No wonder the current mission rover Chang’e-4 collects data in the Aitken crater at the South Pole.
There are enough useful resources on the moon. Oxygen inside the regolith can be extracted and used for breathing. Its most likely source is the mineral ilmenite (FeTiO3), which, in combination with hydrogen at a temperature of about 1000° C, produces water vapor, which must then be separated to produce hydrogen and oxygen.
Moreover, future moon colonizers need to take care of the food. Food production in space is not a new idea. It began developing in 1982, when Soviet cosmonauts first grew the Arabidopsis thaliana flower on the space station, Salyut-7.
Since then, hydroponics (growing plants on artificial environments without soil) took a step forward, and in 2010, the University of Arizona (the USA) developed a prototype named “Lunar greenhouse”. The hydroponic system uses a 5.5-meter membrane tube, water vapor lamps and “envelopes” to hold seeds with carbon dioxide exhaled by astronauts.
In 2018, with the help of such a system, the Neumayer III-polar station team in Antarctica harvested the first crop grown in greenhouses without land and sunlight: 3.6 kg of lettuce, 18 cucumbers, and 70 radishes. In a high-tech greenhouse, behind the walls of which the temperature was kept at -20° C, a reusable water cycle, a nutrient system, LED lighting and careful control of carbon dioxide were used.
For the construction and life support of the lunar base, a large amount of energy will be needed, and the Sun is far from its only source.
According to ESA scientific adviser Aidan Cowley, during the night, the water extracted from the ice can be divided and recombined to produce electricity. He said that there would be a lot of solar energy during the day, which would help dividing water into hydrogen and oxygen. This is a unique tool that they could use on the moon to provide energy for a long-term mission.
There is also the possibility of accumulating energy through heat pumps.
There is no wind on the moon, and the heat from the sun remains in the regolith. Cowley suggested to use a lens or a mirror to focus sunlight at a specific point on the surface, and use this resource to heat the base or generate electricity.
Once scientists figure out these technologies and test them, humans will be able to build a moon base and ultimately moon colonization