By now, it's pretty much a given that human beings will be going to Mars eventually. While Elon Musk, Boeing, NASA et al. continue to duke it out to see who can take us to the Red Planet first, scientists have begun looking at another pertinent question, namely: Where are we going to live once we get there? The latest design concept unveiled by researchers at NASA's Langley Center makes use of an abundant Martian resource – water – to bring the igloo into the space age.
Past ideas have included a show home constructed out of Martian regolith, a 3D printed ice house, inflatable shelters made from recycled spacecraft materials, and using robots to build subterranean basalt shelters. Just like the aforementioned concepts, the idea behind the Langley Centre's Ice Home is to use the planet's resources to build a habitat that would protect inhabitants from the elements and harmful galactic cosmic rays, as well as minimize the costs of transporting raw materials from earth.
The Ice Home was developed in collaboration with the team from Space Exploration Architecture (SEArch) and Clouds Architecture Office (Clouds AO) that won first prize in the first round of NASA's 3D Printed Habitat Challenge Design Competition and is a "sound engineering solution," says Langley senior systems engineer Kevin Vipavetz. Ice Home principal investigator Kevin Kempton, part of the Langley team, goes one step further and declares it "currently the best solution out there for an early Mars outpost" as it offers several advantages over underground bunkers and aluminum structures.
One of the Ice Home's key features is its inflatable outer shell, which can store water (and there is a lot of it that can potentially be mined on Mars) in cellular pockets and use it as a shielding material for cosmic rays. In addition, there's also the possibility the water could be converted into fuel for the Mars Ascent Vehicle.
Secondly, the Ice Home's lightweight design offers early colonists a practical advantage as it can be transported and deployed easily with simple robotics. In the case of underground bunkers, one would first need to excavate the soil, which would in turn require the use of heavy machinery that would need to be transported from earth.
Finally, the ice would also allow natural light to pass through, a seemingly trivial but important factor to consider for maintaining mental health and morale in an alien environment.
"All of the materials we've selected are translucent, so some outside daylight can pass through and make it feel like you're in a home and not a cave," says Kempton.
To maintain indoor temperatures at a comfortable 72º Fahrenheit (22º Celsius), carbon dioxide in the atmosphere would be used as an insulation layer between the structure's interior and outer ice shell. Kempton also believes that the Ice Home has the potential to hold pressure better than most 3D printed structures made of regolith – the pressure in its living quarters is expected to be around 14.7 pounds per square inch. A key highlight of the Ice Home is a pressurized workspace large enough for a crew of four. Here, they'll be able to work on robotic equipment without having to wear a pressure suit all the time to avoid the danger of inhaling toxic dust particles. "When we go to Mars, we will stay there for a long time," Kempton told Space.com. "We will need a place to service the robotic equipment that will be out there working for us in very difficult environments. Doing work while wearing pressurized gloves is a lot like wearing clown gloves, and simple things are hard to do and your hands get tired real quickly."
That said, this project is still in its conceptual stages and further iterations could very well be in the pipeline. While ice exists in plentiful supplies on Mars, scientists have yet to find an efficient and cost-effective way of extracting it from the ground. Based on hypothetical rates (i.e. one cubic meter - or 35.3 cubic feet - per day), it would take more than a year, or 400 days to be exact, to fill up the shell with water. Comprehensive testing would also have to be conducted to ensure each aspect of the technology is able to work in the harsh Martian landscape. Apart from cosmic rays, colonists will have to contend with ultraviolet radiation, charged-particle radiation, possibly some atomic oxygen, perchlorates, and dust storms, points out Langley researcher Sheila Ann Thibeault.
Perhaps it is worth noting that Rob Mueller, a senior technologist at NASA and one of the judges of the 3D Printed Habitat Challenge, described the winning Ice House design by SEArch and Clouds AO as "the most innovative but maybe not the most practical." Indeed, the use of water is actually a detriment in Phase 2 of the competition, which will be assessing entries on their practicality and feasibility.
In any case, this is just one of many potential concepts for long-term habitation on the Red Planet. However one thing is certain: Though the early Mars settlers will be boldly going where no man has gone before, they will not be having it easy, hence the importance of having not just a functional temporary abode but a decent place to call home.
"After months of travel in space, when you first arrive at Mars and your new home is ready for you to move in, it will be a great day," says Kempton.