StarCrete: A Starch-based Biocomposite For Offworld Construction

March 16th 2023

Potato starch and Martian soil make ‘cosmic concrete’ for extra-terrestrial structures – just add astronaut tears.

Simulated Martian soil, potato starch and salt have been combined into a new concrete-like material that could one day be used to build structures on Mars.

The tough new material, known as StarCrete, was developed by a team of researchers at the University of Manchester.

Using terrestrial materials to build infrastructure in space would be “prohibitively expensive and difficult to achieve” with current methods, the researchers said. Instead, future space construction will need to rely on simple materials that are easily available to astronauts.

StarCrete offers a possible solution, the researchers claimed. The material is reportedly twice as strong as ordinary concrete, and could be perfectly suited for construction work in extra-terrestrial environments.

The team used ordinary potato starch as a binder, mixed with simulated Mars dust to create StarCrete. Testing showed that the material has a compressive strength of 72 Megapascals (MPa), over twice as strong as the 32 MPa of ordinary concrete. StarCrete made from Moon dust was even stronger, at over 91 MPa.

This work improved on a previous project from the same team, which theorised that astronaut blood and urine could be used as a binding agent. While the resulting material had a compressive strength of around 40 MPa, the process had the drawback of requiring blood on a regular basis. When operating in an environment as hostile as space, this option was seen as less feasible than using potato starch.

“Since we will be producing starch as food for astronauts, it made sense to look at that as a binding agent rather than human blood,” said lead researcher Dr Aled Roberts, research fellow at the Future Biomanufacturing Research Hub.

“Also, current building technologies still need many years of development and require considerable energy and additional heavy processing equipment, which all adds cost and complexity to a mission. StarCrete doesn’t need any of this and so it simplifies the mission and makes it cheaper and more feasible.

“And anyway, astronauts probably don’t want to be living in houses made from scabs and urine!”

Either way, the future astronauts might have to make some sacrifices to build their extra-terrestrial homes – the researchers discovered that magnesium chloride, a common salt found in tears, “significantly improved” the material’s strength. Thankfully, it should also be obtainable from the Martian surface.

The researchers calculated that a 25kg sack of dehydrated potatoes contains enough starch to produce almost half a tonne of StarCrete, equivalent to 213 bricks – a three-bedroom house takes roughly 7,500 bricks to build.

Dr Roberts and his team recently launched a start-up company, DeakinBio, which is exploring ways to improve StarCrete so it can also be used in a terrestrial setting.

If used on Earth, StarCrete could offer a greener alternative to traditional concrete, the researchers claimed. Cement and concrete account for about 8% of global carbon dioxide emissions, as the process by which they are made requires very high firing temperatures. StarCrete can be made in an ordinary oven or microwave at normal home baking temperatures, reducing the amount of energy required.


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