Berlin/Hannover – What does man actually want on the moon? Some people ask themselves that when they look at the great earthly problems. But basically it is also reassuring that there are still researchers who are driven by curiosity: to explore the universe further and to prepare new space missions – also to possibly find solutions to earthly problems.
The moon is very well suited for such plans – as a possible research station and "springboard" for spaceships. For some time, various space organizations have been considering installing a permanent base on the moon that people can also live in. In this context, the Technical University (TU) Berlin is planning a flight to the moon together with the Laser Center Hanover (LZH). Researchers want to test how landing pads, roads and buildings could be built on the moon.
Material transport for lunar station would cost a million dollars per kilo
"With costs of up to one million dollars per kilogram, a complete transport of the material from earth to the moon would be extremely expensive," says Jörg Neumann, head of the "Moonrise" project at the LZH. Therefore, an attempt should be made to erect the structures on site, using lunar dust, also known as regolith. This is a layer of powdered moon rock up to fifteen meters thick with very special properties.
LZH
The newly developed laser on the robotic arm of a moon roverThe scientists want to bring a laser system to the moon that melts the lunar dust. Artificial intelligence (AI) is intended to support this process. Experiments on the moon are intended to lay the foundations for a possible 3D laser printing technology that will one day be able to “print” parts for the future infrastructure on the moon.
Laser test under lunar conditions – but on Earth
According to the TU, the scientists succeeded in melting real moon dust in the experiment under conditions of lunar gravity. This happened in the Einstein elevator of an institute at the Leibniz University in Hanover. The moon has only a sixth of the gravitational pull that exists on earth. So if you weigh 60 kilograms on earth, you would weigh just ten kilograms on the moon. This also has an impact on moon dust, for example, because the particles thrown up sink back to the surface more slowly.
Something like this has to be considered for future technologies. According to the report, the Einstein Elevator – a more than 20 meter high drop tower in Hanover, which makes experiments in weightlessness and in a vacuum possible – has succeeded in melting regolith into coherent structures under conditions of lunar gravity. The laser head was controlled by a rover's robotic arm, similar to what could be used on the moon in the future.
LZH
The research team has already succeeded in using the laser to melt lunar dust into coherent structures. The laser head is about the size of "a large juice pack" and still withstands the adverse conditions in space, said one of the researchers involved. Although it is not yet possible to build larger building blocks or even an entire lunar station with the melted lunar dust "orbits", the scientists believe that the beginning has been made.
A modular system made of moon dust serves as an aid to the TU Berlin
The modular system serves to represent the different compositions of the regolith at the possible landing sites by means of terrestrial rocks. This should then happen in the TU laboratory, depending on where the landing apparatus comes to a standstill, so that “the laser and the AI can be aligned to the real moon mission”, as Benedict Grefen from the Exploration and Propulsion working group in the TU’s Space Technology department explains Berlin explained.
The flight to the moon is planned for the year 2024. Details are not mentioned. The project is called "Moonrise-FM" and will run for three years. It is funded by the Federal Ministry of Economics with 4.75 million euros. The project sponsor is the German Aerospace Center (DLR).
The moondust – great danger and hope at the same time
The challenges of living and working on the moon are very great. And one reason for this is the moon dust, which should not only be used as a building material – but with which you have to learn to deal with first. It sticks to boots, gloves and everything that comes into contact with it – apparently due to electrostatic charging from the sun's rays. This was the experience of Apollo astronauts, who always brought some dust into the cabin after returning from a walk on the moon. It was soft as snow, yet "rough" and smelled like spent gunpowder, they said.
Lunar regolith consists of silicon, aluminum, calcium, iron, magnesium, titanium and other substances. It is more like sand than dust. It was created over many billions of years by the unbridled bombardment of chunks from space, which shattered and literally pulverized the crustal rock. Particles from the solar wind – mainly hydrogen, helium, neon, carbon and nitrogen – are stored in the lunar dust. One speaks of a kind of archive of the solar wind.
The individual particles are not rounded off by water, wind and weather, but have sharp edges. Among them are also glass splinters, which were created by the high heat of asteroid impacts. The lunar dust destroys zippers on space suits and irritates the respiratory tract and eyes of astronauts returning from spacewalks. It can get into seals and mechanical components, damage optics and solar cells. In a 2005 study, the US space agency Nasa classified moon dust as the greatest challenge for future moon missions.
But the lunar dust is also a reason why people are considering settling on the moon at all. Economic hopes are focused, among other things, on rare raw materials such as iridium and other metals. Moon dust could serve as a storage medium. And helium-3, an extremely rare isotope of the noble gas helium on Earth, could be used in coolants, measuring instruments and future fusion reactors.
Possible benefits of staying on the moon
In this respect, the eyes of different nations are fixed on the moon. The US space agency Nasa in particular has big plans after the course “To the moon!” was announced again in 2019. Because the moon's weaker gravity and lack of an atmosphere drastically reduce the fuel requirements for rockets, the moon could serve as a platform for manned missions to Mars, for example.
As part of its Artemis program, Nasa is planning a space station in orbit around the moon, supported by international cooperation. At some point, a lunar base – the so-called Artemis Base Camp – is to be built, probably near the Shackleton Crater at the south pole of the moon. It is said that there is always enough sunlight on the high rim of the crater, so that solar modules can produce enough electricity at any time. In addition, water is suspected in the four-kilometer-deep crater, in the form of ice.
NASA
This is what Nasa's Artemis Base Camp could look like one day. But other organizations also want to be there on the moon. At the beginning of 2019, for example, a space probe landed on the far side of the moon for the first time: the Chinese probe "Chang'e 4" with a robotic vehicle. Other plans so far envisage, among other things, that a Russian-Chinese research station should be built on the moon around the 2030s, in which other partners could possibly also participate. Nobody knows what will become of it in view of the current events on earth.
Astronomers are particularly interested in the far side of the moon. Particularly powerful telescopes could be set up here for further exploration of the universe, because the conditions for observations are very good. But not because the back is "always dark," as one recent account put it — which likely stems from Pink Floyd's "The Dark Side of the Moon."
No, all sides of the moon are lit by the sun over the course of a month. The back remained "dark" for people for a long time because they can only see one side at a time – because of the fixed rotation. But when there is a new moon, for example, the moon is between the earth and the sun and is illuminated "from behind".
The moon is simulated in Cologne
The bottom line is that the far side of the moon is unaffected by interfering radiation from Earth—radar, WiFi, cell phones, and satellites. At the same time, there is no atmosphere (ionosphere) on the moon, which mainly "swallows" radio waves of lower frequencies on earth. For example, you could use a radio telescope on the back of the moon to carry out astronomical measurements that are not possible on Earth – for example, explore the universe as it looked 300,000 years after the Big Bang.
Years ago, the Europeans considered building a large long-wave radio telescope on the far side of the moon as a first step towards a manned European lunar station. Jan Wörner, Director General of the European Space Agency (ESA) until February 2021, also campaigned in 2016 for a "Moon Village" that should be open to all interested nations. Not much has happened in this direction so far. The Europeans are primarily involved in the current NASA moon program – with the supply of equipment and technology and possibly with their own astronauts.
DLR/ESA/F. Rometsch/CC-BY
Lunar landscape inside the planned Cologne Luna Hall However, a lunar training facility is to be built at the European Astronaut Center in Cologne to prepare astronauts for longer stays on the moon. The funding decision from the state of North Rhine-Westphalia came in March 2022. The system is called Luna and is a joint project by Esa and DLR. Among other things, the plan is to replicate the surface of the moon in a large hall, a moon dust simulator, day and night simulations, test facilities for technologies and a residential module called Future Lunar Exploration Habitat, or FlexHab for short.
Incidentally, the moon dust for the system comes from Germany. It's a regolith substitute made from volcanic powder that's 45 million years old and derived from volcanic eruptions in the nearby Eifel region. With this, the surface of the moon is to be reproduced in Cologne.
It will probably be a long time before dwellings are made from real moon dust on the moon – maybe even in an international cooperation like the one Jan Wörner had in mind in 2016. At the moment there is more of a danger that the moon will become a kind of mirror image of the earth: with the conflict or even the enmity of competing nations.
