From 2024, the Mars One mission plans to launch a crew of four settlers every two years to establish a permanent human colony on Mars. NASA engineer Behrokh Khoshnevis from the University of Southern California in the US has spent the past two years inventing robots that can be sent to Mars ahead of the colonists to set up all the basic infrastructure they'll need when they get there.
According to Sydney Brownstone at FastCompany, Khoshnevis has been working with a new method of construction called ‘contour crafting’, which allows robots to 3D-print huge concrete objects such as buildings. Last year he predicted that his 3D-printed concrete technology would be available by 2015, and was able to print the concrete shell of a 600-square-metre house in less than 20 hours.
The technology is ready, says Khoshnevis, but adapting it to Mars has posed some unusual problems, like where would the concrete come from?
"One of Khoshnevis’s breakthroughs came by way of sulphur concrete,” says Brownstone at FastCompany. "There’s about four times as much sulphur in Martian soil as there is on Earth, and Khoshnevis discovered that it could help bind jagged bits of space rock together. But even once he began using sulphur concrete, extruding the material still proved difficult. Compared to Earth beach sand, Martian and lunar sand is pretty abrasive.”
“Beach sand [particles] have been rubbed against each other by the waves for billions of years, so it’s not as sharp as particles of lunar material,” Khoshnevis told Brownstone. "For billions of years these dust particles have not moved; there is no wind. So it’s like 10 times harder to move them than sand on Earth.”
Despite the challenges posed by Martian concrete, there are some positives to setting up a robotic construction site on the Red Planet. The gravity on Mars is 62% lower than it is on Earth, which means things are lighter and will need to withstand much less pressure. This means anything built here would last a whole lot longer than if they were built on Earth.
Here's NASA's simulation of what the robots might look like on Mars: