ESA title
Strength comparison
Science & Exploration

Astronaut urine for building a Moon base

08/05/2020 7426 views 86 likes
ESA / Science & Exploration / Human and Robotic Exploration

From human waste to superplasticiser, astronaut urine could become a useful resource for making a robust type of concrete on the Moon.

Recent ESA research shows that urea, the main organic compound found in our urine, would make the mixture for lunar concrete more malleable before hardening into a final, sturdy shape for future lunar habitats.

Researchers found that adding urea to the lunar geopolymer mixture, a construction material similar to concrete, worked better than other common plasticisers, such as naphthalene or polycarboxylate to reduce the need for water.

Printing a new urea-based mortar
Printing a new urea-based mortar

The mix coming out of a 3D printer proved to be stronger and retained a good workability – a fresh sample could be easily moulded and retained its shape with weights up to 10 times its own on top of it.

“The science community is particularly impressed by the high strength of this new recipe compared to other materials, but also attracted by the fact that we could use what’s already on the Moon,” says Marlies Arnhof, initiator and co-author of the study from ESA’s Advanced Concepts Team.

Using only materials available on site – an approach known in the space arena as In-Situ Resource Utilisation, or ISRU – will reduce the need of launching huge volumes of supplies from Earth to build on the Moon.

The main ingredient would be a powdery soil found everywhere on the surface of the Moon, known as lunar regolith. The superplasticiser urea limits the amount of water necessary in the recipe.

Lunar soil simulant
Lunar soil simulant

Thanks to future lunar inhabitants, the 1.5 litres of liquid waste a person generates each day could become a promising by-product for space exploration.

“Urea is cheap and readily available, but also helps making strong construction material for a Moon base,” points out Marlies.

Why urea?

Urea mix sample
Urea mix sample

After water, urea is the most abundant component of human urine. Urea can break hydrogen bonds and reduce the viscosities of fluid mixtures. Urine also contains calcium minerals that help the curing process.  

On Earth, urea is produced on an industrial scale and widely used as an industrial fertiliser and a raw material by chemical and medical companies.

“The hope is that astronaut urine could be essentially used as it is on a future lunar base, with minor adjustments to the water content. This is very practical, and avoids the need to further complicate the sophisticated water recycling systems in space,” explains Marlies.

Bring it into the mix

Malleable urea for lunar concrete
Malleable urea for lunar concrete

Several tests confirmed that this type of concrete mixed with urea was capable of withstanding harsh space conditions such as vacuum and extreme temperatures. These two factors have the biggest effect on the physical and mechanical properties of construction material for the lunar surface.

All samples were subjected to vacuum and freeze-thaw cycles to simulate the sharp temperature changes throughout lunar days and nights, which might vary from -171°C to 114°C. The samples withstood temperatures ranging from 114°C to -80°C as a good indication of how the material would behave under even lower temperatures.

Community building

A close collaboration between ESA researchers in the Netherlands and universities in Norway, Spain and Italy under the Ariadna initiative “allowed us to look into such an exploratory, somewhat risky idea that can bring valuable results not only for space exploration, but also for technology applications on Earth,” explains Shima Pilehvar, co-author of the study and associate professor at Østfold University College, in Norway.

“Industry could benefit from refined recipes for fire and heat resistant inorganic polymers suitable for additive manufacturing,” she adds.

One of the hot topics the team wants to tackle next is how basalt fibres from the Moon could reinforce the concrete and how the material could be best used to shield a lunar colony. Researchers hope that this new urea-based mortar could help protect future astronauts from harmful levels of ionising radiation.

Lunar base made with 3D printing
Lunar base made with 3D printing

Related Articles

Moon seen from Space Station
Science & Exploration

To the Moon – down south

16/07/2019 8011 views 80 likes
Read
The Moon as seen from the Space Station
Applications

ESA identifies demand for satellites around the Moon

16/07/2019 4241 views 81 likes
Read
Heracles
Science & Exploration

Developing a high-performance rocket motor for the Heracles…

16/05/2019 2321 views 32 likes
Read
ALINA on the Moon
Science & Exploration

Starting up a new cooperation for the Moon

08/05/2019 2751 views 26 likes
Read
Testing the Heracles lunar rover
Science & Exploration

Guidance and navigation systems for Heracles

18/04/2019 840 views 8 likes
Read
Moonrise
Science & Exploration

ESA and NASA to team up on lunar science

28/03/2019 7891 views 128 likes
Read
Space gateway
Science & Exploration

Gateway to the Moon

11/03/2019 15340 views 225 likes
Read
In-Situ Resource Utilisation
Science & Exploration

Astrobotic team to study delivery of lunar resources mission

26/02/2019 1076 views 10 likes
Read
The extent of Earth’s geocorona
Science & Exploration

Earth’s atmosphere stretches out to the Moon – and beyond

20/02/2019 72093 views 291 likes
Read
Moon dust on astronaut after moonwalk
Science & Exploration

Project Pextex: materials for lunar spacesuits

15/02/2019 3567 views 49 likes
Read
Multispectral view
Science & Exploration

A new camera for lunar exploration

29/01/2019 993 views 7 likes
Read
Helga, the radiation dummy
Science & Exploration

Radiation for dummies

25/01/2019 11116 views 135 likes
Read
Science & Exploration

Preparing astronaut lunar exploration

23/01/2019 5092 views 75 likes
Read
Creativity room at EAC
Science & Exploration

Bold ideas for life off Earth

24/01/2019 1180 views 15 likes
Read
Space Station Moon
Agency

Moving on the Moon

23/01/2019 6781 views 92 likes
Read
Lunar attraction
Science & Exploration

Total lunar eclipse 2019

18/01/2019 18680 views 97 likes
Read
Station Moon transit
Science & Exploration

Moon engine now in development

08/10/2018 4870 views 68 likes
Read
1.5 tonne building block
Science & Exploration

Bricks from Moon dust

20/08/2018 16764 views 155 likes
Read
The Moon as seen from the Space Station
Science & Exploration

The toxic side of the Moon

04/07/2018 19725 views 511 likes
Read
Brick 3D printed from moondust using focused sunlight
Enabling & Support

Printing bricks from moondust using the Sun’s heat

03/05/2017 13230 views 134 likes
Read
Goonhilly antenna
Enabling & Support

Goonhilly goes deep space

22/02/2018 5454 views 97 likes
Read
Science & Exploration

First steps: returning humanity to the Moon

20/09/2017 17241 views 292 likes
Read
In-Situ Resource Utilisation
Agency

Water and oxygen made on the Moon

2425 views 15 likes
Read

Related Links