What Is AstroCrete? ‘Concrete’ Created By Scientists Using Astronauts' Blood, Sweat, Tears For Housing In Outer Space

Researchers explain in a study how astronaut blood can be used as a binder, along with extraterrestrial dust, to create cosmic concrete that could serve as building material for Martian colonies

Moon and mars biocomposites (left); and 3D-printed Mars biocomposite | Photo: University of Manchester

New Delhi: Space giants are aiming to send the first humans to Mars. Building a Martian colony up there is also not a far-fetched reality any more — only, it’s far too expensive.   

Carrying a single brick would reportedly result in an expenditure of US $2 million.

This means the colonists must use the resources available on Mars, in order to terraform it.

In a recent study published in the Materials Today Bio journal, researchers from the University of Manchester have said how cosmic concrete can be created using space dust, mixed with astronauts’ blood, sweat, urine, or tears.

The researchers explain that expenses associated with the future construction of a Martian colony can be reduced significantly, by using extraterrestrial dust along with the astronauts' blood, sweat, urine and tears, to develop a material similar to concrete. 

For the resulting novel material, they have coined the term AstroCrete.

What Is AstroCrete And How Can It Be Developed?

The utilisation of resources on the Martian surface, like inorganic rock and dust, known as regolith, and water deposits and atmospheric gases, is known as In Situ Resource Utilisation (ISRU). The crew themselves would be important resources for ISRU. 

ISRU will help in the development of AstroCrete, the researchers explain. They have demonstrated that human serum albumin (HSA), a common protein obtained from blood plasma, can be used as a binder for simulated Lunar and Martian regolith, to develop extraterrestrial regolith biocomposites (ERBs), which is an organic matrix of mineralised composites. Occasionally, HSA produced by astronauts would be extracted, and combined with Lunar or Martian regolith to "get stone from blood", the researchers note. 

A simple fabrication strategy was used to develop the HSA-based ERBs, which were found to exhibit high compressive strengths. The compressive strength of normal concrete ranges from 20 to 32 Megapascals (MPa) and these ERBs had a strength of 25 Megapascals. 

The scientists also explain that the strength would increase by more than 300 per cent, if urea extracted from astronauts' urine, sweat or tears is incorporated. The best formulation exhibited a compressive strength of 39.7 MPa, which is substantially stronger than ordinary concrete. 

The researchers also demonstrated that HSA-ERBs could be 3D printed, which would allow extraterrestrial construction using feedstocks derived from humans. 

Adhesion of AstroCrete

The scientists performed dehydration of HSA, which caused the secondary protein structure to be reorganised. A beta sheet network, having dense hydrogen bonding is formed, and the process is analogous to the cohesion mechanism of spider silk. The blood proteins denatured or curdled to form the beta sheets, which can strongly hold the material together.

The scientists also investigated the use of synthetic spider silk and bovine serum albumin (BSA) as regolith binders. 

Through a graphical illustration, the researchers explain how regolith biocomposites could be produced directly from the Martian environment. Nitrogen (N2), water (H2O) and carbon-dioxide (CO2), which are abundant in the Martian environment, could be used for Food production and creation of Oxygen (O2). Food, Water and Oxygen will be consumed by the astronauts, and HSA and Urea produced from them will be used to create regolith biocomposites. 

With future advancements in biomanufacturing technology, production of ERBs would be feasible.

Is This Better Than Other Proposed Techniques?

Dr Aled Roberts, one of the researchers, said this technique is more advantageous than other proposed techniques, as it could be used to produce more than 500 kg of high-strength AstroCrete during a two-year mission on Mars, led by a crew of six astronauts, according to a statement issued by the University of Manchester. 

He explained that each astronaut could use AstroCrete to build a habitat for an additional crew member, which means that each mission will double the available housing. 

Calling the concept “literally blood-curdling", Dr Roberts said the technique draws inspiration from a mediaeval technology in which animal blood was used as a binder for mortar.