One giant leap

With the first human off-world habitats proposed and potentially on site within a decade, construction technology and expertise are now the driving force behind our adventures in the solar system.

Humanity has long been dreaming of colonising other planets, and what was once a sci-fi fantasy is now close to becoming a reality. Thanks to advancing rocket technology, improved knowledge of extra-terrestrial environments and innovative construction technology, scientists and engineers are now working to create the first off-world habitats.

Building on another planet is a cosmic challenge, but not an entirely alien one to construction teams on Earth, which is why NASA, the European Space Agency (ESA) and private companies such as Space X and Mars One have sought input from architects and other consultants when preparing designs for settlements.

Advanced and resilient new structures will be required to deal with the different states of gravity and atmospheric conditions, as well as more unique dangers such as meteor strikes or dust storms.

Jeffrey Montes is space architect at New York-based design agency AI’s SpaceFactory, whose “Marsha” (MARS HAbitat) concept is a finalist in the latest phase of a NASA competition to build a 3D-printed habitat on Mars.

Marsha envisions a series of vertical egg-shaped pods, each with a hard protective outer casing, able to contain the internal atmospheric pressure, and a disengaged inner shell filled with mission-focused rooms and living spaces. In its submission for the same challenge, Team Kahn-Yates, from Mississippi, designed smaller individual volumes with sleek oblong forms intended to minimise the impact from dust storms.

Turning its attention to the Moon, a consortium led by Foster + Partners worked with the ESA to propose a dome-shaped facility, strong enough to withstand the effects of a meteorite strike, and solar gamma radiation that can penetrate the dusty surface.

The huge distances involved in space travel impose severe constraints on the logistics and cost of transporting equipment and construction materials. Mars is 140 million miles from Earth and, given about 90% of the mass of a typical rocket is propellant, space for additional payload is limited (see panel).

In most scenarios this will require building using local natural resources, a process known as in-situ resource utilisation (ISRU). Habitats would likely be 3D printed by robots using minerals found in regolith, the loose soil and dirt found on the Moon and Mars.

In a winning proposal for phase two of the NASA Mars Habitat competition, Foster + Partners proposed using two types of semi-autonomous robot: one that processes regolith and one that uses microwaves to fuse the material in place. A series of connected inflatable modules would be protected by a separate self-supporting outer shield 3D printed from a mix of locally sourced basalt fibre and high-density polyethylene, imported from Earth.

Apart from soil, the anticipated abundance of water in certain regions of Mars could lead to the creation of 3D-printed “ice habitats”, such as the one proposed for the NASA competition by Space Exploration Architecture and Clouds Architecture Office. Arkansas-based Team Zopherus’s proposal, meanwhile, would involve printing a collection of hexagonal structures using a composite Martian concrete made from ice, calcium oxide and local aggregate.

But ISRU doesn’t entirely rule out the shipment of structures from Earth. In July NASA and Autodesk announced they had been experimenting on printing human-habitable structures made of lightweight materials that can be easily hauled into space and reassembled on other planets.

The first construction projects on the Moon or Mars will run very differently from their terrestrial counterparts, replacing human labour almost entirely with robots to avoid the hazards associated with cumbersome space suits and low gravity.

NASA has stipulated that habitats should be completed, with life-support systems in place, before humans arrive. Machines would therefore be sent in advance to quarry the Martian landscape and then 3D print homes. Due to Earth radio signals being delayed by up to 20 minutes, the robots would need to work autonomously.

Proposals for Moon bases have tended to focus on sending up a few robots to carry out printing, but the complexity of landing on Mars, and the operational risks, would probably mean building in more redundancy.

Once the habitats are built, next comes the challenge of running and maintaining them to support life and produce their own power, food, oxygen and water.

Possible operational scenarios are being explored through the Mars City Facility Ops Challenge, an educational project set up by the National Institute of Building Sciences (NIBS), NASA, and the Total Learning Research Institute, which places high-school students in a virtual reality simulation of a Mars base where they use software to complete facilities maintenance tasks.

“On an environment like Mars you are forced to think in terms of sustainability and resilience. You can’t go to the DIY store if you need parts. There aren’t any additional energy sources. It means thinking holistically about the project and maintaining systems,” says Ryan Colker, vice-president of NIBS.

A key concern is the life-threatening nature of extraterrestrial environments, and monitoring pressure seals, air filters, scrubbers used to produce oxygen and hydroponic food production.

“Mars demonstrates the importance of a preventative-maintenance regime,” says Colker. “Upfront design in BIM will likely be crucial when planning the design of habitats and testing out maintenance scenarios and training simulations before the first lander touches down.”

If SpaceX’s CEO Elon Musk is correct, then the first Mars settlers will land on the Red Planet in 2020, so initiatives like Mars City could be crucial to encourage the current young generation to live and work off-world. “If we can inspire and engage them now, who knows where it will take us in future,” Colker concludes.