Constructing Mars bases will be expensive due to the vast cost of transporting heavy materials, but researchers have found one way to cut down the price: mixing native planetary soil with astronaut blood and urine to make building supplies.
at the University of Manchester, UK, and his colleagues extracted a protein from human blood called serum albumin, which is vital in maintaining the balance of fluids in the body, and used it to bind together simulated Mars soil听to produce a concrete-like material that the team calls AstroCrete.
The material has a compressive strength of up to 25 megapascals once cured by thorough dehydration, which is comparable to concrete. But when combined with urea, which is excreted by humans through urine, sweat and tears, this strength increases to almost 40 megapascals. Using urea alone didn鈥檛 achieve the same effect.
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The researchers found that the material could even be used in 3D printers, and conducted experiments using a syringe to manually build layers that dried to form stable structures.
Given the complexity of space travel, the cost of transporting even a single brick to Mars would be huge, meaning that future Mars colonists are unlikely to be able to take their own building materials with them. AstroCrete could provide a solution 鈥� although an initial habitat made of traditional materials would be needed to house the first colonists.
The researchers calculate that more than 500 kilograms of AstroCrete could be safely produced over the course of a two-year mission on the surface of Mars by a crew of six via blood donations. But they admit that research into the physical and mental effects of constant blood donation in low gravity would need to be conducted first.
It is possible to extract blood, separate the cells from the plasma that contains the albumin and put the cells back into the donor. This is less stressful for the body and would allow two donations of 1.2 litres of plasma each week for healthy adults. Each litre of plasma contains up to 50 grams of the required protein.
at the Singapore University of Technology and Design is sceptical about the proposal, as it would require a large amount of blood that the astronauts would need to replenish. He says: 鈥淏lood doesn鈥檛 seem a good choice since it is not a byproduct of a process but the main element of human life.鈥�
at the University of Arizona also warns that simulated Mars soils often aren鈥檛 meant to capture chemical reaction properties, only mechanical ones. 鈥淭o date, we have Martian simulants but not real Martian regolith. To have sufficient confidence in the process, the blood-binding process would need be evaluated with real Martian regolith.鈥�
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