By its proximity to Earth, the moon is destined to become the first permanent base of humans on a foreign cosmic body. Scientists are therefore wondering how and what to build there.
Building materials are one of the key problems of the Moon's (and alien planet's) settlement plans.
Transport to the Moon is expensive. Shipping a kilogram of cargo from Earth costs about $ 22,000. It is therefore necessary to make the most of building materials and additives that can be obtained directly on the moon.
We already know that there is a regolith – unpaved rock that forms the surface of the moon, or water that is in the form of ice on the poles. However, a plasticizer, which is often added to cement, concrete and other building materials, will also be necessary.
Where to get it? Astronauts can make it themselves – from their own urine.
Urea as a plasticizer
The study by Shiva Pilehvar of Østfold University College, Norway, concluded that human urine can be an important additive to lunar concrete.
It would soften the lunar structures to provide flexibility and thus protect them from cracking. The conditions on the Moon are extremely terrestrial, with temperatures ranging from -130 ° C to +120 ° C.
Building on the moon is possible by 3D printing of bricks from lunar soil – regolith. As with bricks on Earth, however, you need water, like lunar ice, as well as a plasticizer.
A new study also mentions that an astronaut's urine aqueous solution could be used instead of pure ice water.
Tests of simulated lunar soil enriched in urea have already confirmed that this additive is a good plasticizer. It improves workability, reduces brittleness of bricks and increases their resistance to compression.
“We haven't investigated how urea will be extracted from the urine of astronauts,” said co-author Anna-Lena Kjøniksen. “We were just studying whether it would work for something. And we came to the conclusion that urine water solution can also be an important part of the overall mix.”
The Norwegian study is not the first to identify human waste products as useful in space. A few years ago, for example, the billionaire and the first space tourist, Dennis Tito, planned to send a pair of people to orbit Mars.
The mission was called Inspiration Mars. The vessel should consist of an Orion module, to which the inflatable “residential” module should be attached. The walls of the residential module should be full of separate “pockets” of water, which would protect the crew from radiation.
3D printing using urea source:
The crew should consume water gradually. But it would continue to be protected – the same pockets would store crew waste products, which also contain water, instead of water.
Inspiration Mars did not materialize and its “faecal shield” did not inspire the future of cosmonautics. But on the moon, we can get creative ingredients for the concrete.
Both Inspiration Mars and the latest study show that real conquest of the universe will have to be as effective as possible. And this also applies to waste products, which should have the greatest benefit for the overall survival of the station or later colonies.