x Abu Dhabi, UAEFriday 19 January 2018

Sand could help us reach for stars

A Sharjah-based architecture professor hopes a new substance she is developing could one day see space colonies built on the Red Planet using the UAE's most under-utilised yet plentiful natural resource: sand.

Visitors to Mars may one day shelter from the extreme conditions there in structures made from an innovative, UAE-developed building material formed by bacteria, soil and dust from the red planet's surface.

And robots could pave the way as advance scouts, hunting out areas with the type of soil best suited to the process. Astronauts would then land in these areas and build their bases.

The material is being developed by Ginger Krieg Dosier, an assistant professor of architecture at the American University of Sharjah. She has been working with scientists from the US space agency Nasa who want to investigate how the material could be used in space.

Prof Dosier spent three weeks in the summer working at a Nasa research centre in California's Silicon Valley. She was accompanied by her husband, Michael Dosier, the labs director at the university's College of Architecture, Art and Design, who is assisting her with plans to turn the idea into a commercial reality. Both worked at the Nasa Ames centre under the agency's Education Associates Programme.

The material - which they plan to market under the name Biomason - is made by combining aggregate with bacteria, yeast, calcium chloride, water and urea, a component of urine. Many types of aggregate can be used - including, in places like the UAE, sand.

The mixture is placed in a mould, where a process known as biocementation takes place. The bacteria feed on the urea and, in a series of biological and chemical processes, the microbes transform the calcium into crystals that fuse the loose grains of sand - or Mars dust - together like glue. This produces a strong and durable solid material with a composition and physical properties similar to those of natural sandstone.

Prof Dosier has been testing the process by making bricks, though it could have many other applications. The couple is working towards setting up bigger pilot plants, and hopes one will be in the UAE.

"The process happens in nature in terms of the natural formations of some sandstones, for example, but in terms of the utilisation of this for a masonry construction material, that's our invention," she said.

"We do it in an expedient manner that's viable for construction. It would take microbes thousands of years to do this in nature, whereas we're making bricks in five days, and they match the highest-strength conventional brick.

"Essentially what's happening is we're growing calcium carbonate crystals in between a matrix of sand."

Mr Dosier added: "The bacteria are sort of little workers within this system that are enabling this sort of glue between the particles of sand."

The process is much cleaner than conventional bricks and cement production, which uses lots of energy. Not only that, the raw materials often need to be transported long distances, as do the bricks produced. Forty per cent of global carbon dioxide is linked to the construction industry, and it is estimated that brick manufacturing alone generates more than 800 million tonnes of carbon dioxide each year.

Prof Dosier's method, in contrast, works at ambient temperatures and uses locally available materials - both of which make it an ideal building material for space colonies.

"We were invited by Nasa to look at biocementation in space applications," she said. "If we're going to inhabit Mars then what are we going to make habitations out of? What are our building materials going to be?

"We could use the existing regolith and see what happens. Then the discussion was, does masonry make sense on Mars? If the pressure changes is it going to be able to handle that?"

Mr Dosier, meanwhile, took part in discussions about sending advance parties of robots to Mars. Last month Nasa launched a mobile robot called Curiosity designed to land on the planet and look for conditions that could support life.

"I was looking at how you send up a system that's not overly complicated," he said. "We're not talking about highly intelligent robots that are doing massive decision-making processes, but fairly stupid robots that can make simple decisions.

"You would be looking for signs of suitable aggregates and that's where you would locate the habitats - you'd produce the habitats where you're harvesting the material."

The US president, Barack Obama, has set Nasa a target of launching a manned mission to Mars within 30 years. He said: "By the mid-2030s, I believe we can send humans to orbit Mars and return them safely to Earth. A landing on Mars will follow."

Prof Dosier has spent the past 18 months optimising the production process and slashing the cost of producing single bricks. The next step is scaling it up, first with the pilot plants and ultimately with full-scale factories.

During her time at the Nasa centre she investigated how the process worked at various temperatures between 10°C and 60°C. The best results were between 10°C and 50°C - perfect for the UAE.

"It's our desire to have one of the prototype plants here," Mr Dosier said. "A lot of the research has been designed around looking at local resources here, though we're also looking at locations in depressed agricultural regions in the US where they need jobs.

"In the UAE we're looking at using sand because most of the sand here isn't really used for anything, the sand they use in construction is imported.

"So we're looking at an opportunity to use a natural resource that essentially has very little value, to bring value to it and make use of something that's here."

The couple is working with an ever-growing group of collaborators, including geologists, an industrial engineer and software companies, to push the project forward.

Prof Dosier is taking a term off from her university duties to deal with matters such as applying for International Standardisation Organisation (ISO) certification and exploring possible sources of finance.

"This is the equivalent of being in a marathon, every day we're moving further and further ahead with all the aspects that go into forming a company to manufacture a biological building material," Prof Dosier said. "The list of collaborators keeps increasing because so many different disciplines are required."

The couple is hoping that the first houses to be built with the material will be completed within two to three years. The material could be reinforced with steel in the same way as concrete - opening up the possibility of one day building skyscrapers made of sand.