On this day in 1969, US astronauts Neil Armstrong and Buzz Aldrin were the first humans to set foot on the moon. In honour of that event, 20 July was declared Space Exploration Day (sometimes called Moon Day). 48 years after this event, we are close to setting foot on Mars, so it is time to start preparing for colonising other planets. Today, we look at some of the developments in materials that will help us to live in space. Happy Space Exploration Day!

NASA already presented a type of 3D printed chainmail, while UNStudio and MDT-tex created a shelter to protect you in space. Still, that is not enough if we actually want to colonise other planets.

Living on the moon
Eleven Magazine held an international design competition called Moontopia, which asked the participants to imagine a self-sufficient lunar colony designed for living, working researching and tourism. The winner of the competition was Lunar Test Lab by Monika Lipinska, Laura Nadine Olivier, and Inci Lize Ogun. The structure of this colony is based on the Russion Babushka Doll, where one layer protects the next.

The most important structure is the outer membrane. Based on a simple origami pattern, it can be 3D printed and is assembled on site. If the material is made of programmed carbon fibre, it can even shape itself once it senses pressure variation of solar wind.

The membrane acts as a large protective shell that covers the whole settlement, but that is not all. It also has the purpose to produce water and oxygen. Solar winds on the moon hold hydrogen that can be stored and turned into oxygen.

Mars Ice Home
The surface of Mars has extreme temperatures and the atmosphere does not provide adequate protection from high-energy radiation. Explorers will need shelters to effectively protect them from the harsh Martian environment and provide a safe place to call home.

Researchers at NASA developed such a home, called Mars Ice Home. This house, which looks a bit like an igloo, is a large inflatable torus, a shape similar to an inner tube that is surrounded by a shell of ice. The inflatable torus is lightweight and easy to transport.

Many areas of Mars have abundant ice just beneath the surface. Water, a hydrogen-rich material, is an excellent shielding material for galactic cosmic rays, which pose one of the biggest risks of long stays on Mars. This radiation can pass right through the skin, damaging cells or DNA, increasing the risk of cancer later in life, or acute radiation sickness.

In addition to protecting from radiation, ice has another advantage: it is translucent. Outside light can pass through it, which makes the Mars Ice Home feel actually more like a home than a cave.

Martian concrete
A team of researchers of Northwestern University formulated a type of concrete to build on Mars, of which the main ingredient is another abundantly found on the red planet: soil. The construction material combines Martian soil with molten sulphur and could be used to build an entire village on Mars.

The most important feature of the material is that it made without water, unlike regular concrete, as water is only found in ice form on Mars. The material is also completely recyclable and resistant to acid and salt. It can endure very low temperatures.

3D printed tools
Shelter is of course necessary to live, but humans also need tools. To prevent from having to go back and forth between the Earth and the planet which we might colonise, another team of researchers at the Northwesten University developed a method to 3D print structures with simulants of Martian and lunar dust.

The method is an extension of the 3D-painting process, a term that the researchers use for their novel 3D inks and printing method. They used this process before to print other materials, such as 3D graphene and metals.

People need to use what is available on the planet where resources are limited. The research uses NASA-approved lunar and Martian dust simulants, which have similar compositions, particle shapes, and sizes to the dusts found on lunar and Martian surfaces. The team created the lunar and Martian 3D paints using the respective dusts, a series of simple solvents, and biopolymer, and then 3D printed them with a simple extrusion process. The resulting structures are over 90 per cent dust by weight.

Despite being made of rigid micro-rocks, the resulting 3D-painted material is flexible, elastic, and tough — similar to rubber. The material can be cut, rolled, folded, and otherwise shaped after being 3D painted, if desired.

Aside from tools like wrenches, the researchers also 3D printed Lego-like blocks, which, in theory, could also be used to build shelters.

Photos: Northwestern University / Eleven Magazine / NASA