A new form of concrete made using Martian or lunar soil and animal proteins may allow future astronauts to build colonies on Mars and the Moon, according to Stanford and NASA scientists.
To establish settlements on the Moon or Mars, humans would need thousands of tonnes of concrete to survive. Both Mars and the moon are bombarded constantly with both lethal radiation and micrometeorites that would quickly punch holes into any ordinary structure.
However, since it is nearly impossible to ship such quantities of cement from Earth to Mars, the best way forward would be to start making it in space.
Making Earth-style concrete requires tremendous amounts of heat and energy, which would be very short supply for first human outposts on Mars.
To solve that problem, researchers used animal protein to make a promising form of concrete that could solve problems on Mars as well as Earth.
Living organisms use proteins to make things as tough as shells, bones and teeth, so the researchers including , David Loftus from NASA's Ames Research Centre and Michael Lepech from Stanford University in the US began working on a concrete bound together with a protein from bovine blood.
The protein is a fairly cheap by-product of slaughterhouses, and it is known to become very gluey when mixed with soil.
To replicate the conditions on Mars and the moon, researchers combined the protein with simulated extraterrestrial soils that are similar to what is on Mars and the Moon.
The first batch was as strong as the concrete used for sidewalks and patios - a good start.
It also held up well to a simulated bombardment of micrometeorites, which the researchers replicated by taking the material to the Ames Vertical Gun Range and blasting it with high-speed gas particles.
For the purposes of making concrete on Mars, the idea is to create biological 'factories' of organisms that are genetically engineered to produce the protein binder.
It is the same way that biotech companies use genetically engineered bacteria to make synthetic hormones. The feedstock for those organisms would come from the settlement's recycled organic waste.
One of the big advantages of bio-based concrete is that, unlike in regular concrete, the binding proteins can be recycled time after time. Over years, that can save a lot of energy.