One of the many hurdles standing in the way of a manned mission to Mars is the question of how to build structures on the Red Planet. Transporting all of the materials necessary for space construction would be absurdly expensive, so scientists have proposed a number of alternatives that rely on Martian resources, such as setting up a nuclear-powered kiln, or turning organic compounds on Mars into binding polymers. But a team of scientists at the University of California, San Diego may have (literally) hit upon a much simpler solution: take some Martian soil and squeeze.
In a new study published in the journal Scientific Reports, researchers say that they were able to create solid bricks by smacking Mars-like soils with a high-pressure hammer, Loren Grush writes for The Verge. “Mars-1a,” as the soil simulant is called, is derived from rocks that have the same chemical makeup as Martian soils, along with grains of a similar shape and size.
Most Earthly construction materials are made with the use of a “binder,” which helps the material stay rigid. But researchers found that they were able to form sturdy bricks out of Mars-1a without any type of adhesive. Instead, they relied on a two-step process, reports Abigail Beall for Wired. First, the soil was scooped into a rubber case; then it was compacted using a force roughly equivalent to dropping a ten-pound hammer from a height of about three feet.
The presence of iron oxide, a chemical compound that gives Martian soils their reddish hue, may explain why the bricks stuck together. “[Researchers] investigated the simulant’s structure with various scanning tools and found that the tiny iron particles coat the simulant’s bigger rocky basalt particles,” according to a UC San Diego press release. “The iron particles have clean, flat facets that easily bind to one another under pressure.”
But the technique isn't quite ready yet to be the solution for all Mars-construction woes. In an interview with Alasdair Wilkins of Vocativ, lead researcher Yu Qiao said that the bricks were quite small—about the size of a coin. And the team isn't yet sure how astronauts could efficiently produce these building blocks on Mars. One option, according to the press release, might be to slowly build on compacted layers of soil—much in the way 3-D printing works.
There are other limitations to the study, too. While Mars-1a might be similar to Martian soil, it is not Martian soil. As Sara Fecht points out in Popular Science, the simulant contains about three times more aluminum oxide, and six times more titanium oxide, than the real thing. Scientists can’t be sure, in other words, that soils on Mars behave in the same way as the simulant.
The team’s findings require more research, but the study suggests that in at least one respect, getting humans on Mars could be easier than we thought.