Mars is not a welcoming world for humans or other life as we know it. Even the deepest regions of the Arctic or Antarctic are more hospitable than the most sheltered surface areas on Mars. This is mostly because Earth has an atmosphere highly suitable for life. It contains 78 percent nitrogen, 21 percent oxygen and the last one percent is a mix of trace gases. In comparison, Mars’ atmosphere contains 95 percent carbon dioxide, just under 3 percent nitrogen, 2 percent argon and again some trace gases making up the last fraction of a percent.
The atmosphere of Mars is also relatively thin compared to Earth, which means that even if the gases there weren’t toxic to us, a lungful of air on Mars would be only one fiftieth of what we breathe in on Earth. Further compounding the situation, this thin atmosphere does not absorb the harmful parts of the Sun’s radiation including ultraviolet light and x-rays. As very little heat is trapped on Mars this explains why temperatures can reach as low as -150 degrees Celsius in some regions and times of year. Fortunately the thin atmosphere means that the seasonal dust storms on Mars are relatively weak and likely to cause little harm to any human base.
Speaking of which, a human-made base of operations or artificial habitat will be the first step in settling Mars. Numerous options are being explored by researchers and engineers globally that would provide shelter, radiation protection and the ability to sustain a breathable atmosphere. However, unlike a construction site on Earth, supplies cannot be flown, shipped, or driven from a factory on another nearby part of the planet. Launching all the heavy materials from Earth would be costly and waste precious cargo space. This means that any successful Mars habitat build will rely on existing Mars resources including Martian rocks, ice hidden below the surface or in shadowy craters and caves, and extraction of resources from the atmosphere.
The MOXIE experiment on NASA’s Perseverance Mars rover is a prototype designed to extract carbon dioxide (CO2) from the Martian atmosphere and split it into oxygen and carbon monoxide using extremely high temperatures generated via electricity from the rover power supply. As a proof of concept, this experiment was a success and could be scaled up with a vast array of solar panels to support astronaut air supply and rocket refuelling.
In terms of food, any astronauts on Mars cannot expect to live off rations packaged from Earth. They would again be very costly to take all the way to Mars (not to mention the supplies needed to survive the trip) or on a resupply spacecraft. Instead experiments, like VEGGIE on the International Space Station (ISS) explore options to grow food in space and harsh environments using as few organic resources as possible. So far the crew of the ISS has successfully produced cabbage, lettuce and mustard.
There are some more extreme cutting-edge ideas that investigate the possibility of breaking free of the constraints of small, contained habitats and instead transforming the wider Mars environment. This process is referred to as terraforming. A recent piece of joint research from University of Chicago, Northwestern University in Illinois, and the University of Central Florida outlines the use of specially designed ‘glitter’ to initiate the transformation. Their idea goes beyond what we think of beyond our usage in arts and crafts as the glitter would be made from precisely designed nanoparticles and millions of tonnes of these would need to be jettisoned into the Martian skies. The glitter reinforces the weak heat-trapping power of Mars’ atmosphere by taking sunlight reflected from the surface and bouncing it back again. If the reality matches the hypothesis, the Martian atmosphere could be heated by 10 degrees Celsius over just a few months of launching the specially-designed glitter into the Martian sky.
There is no shortage of ingenious ideas to consider when planning for humans visiting and living long-term on Mars. Our first brave Mars explorers will have challenging times ahead and will put these concepts and prototypes to the test, forging a path for longer missions and perhaps even a new shared home away from home for humans.
About the author
Brendan Owens is a former Royal Observatory Greenwich astronomer. He works at the Institute of Physics, as Public Engagement Manager for Ireland and Northern Ireland. Brendan’s new book, Mars: A beginner’s guide to exploring the Red Planet, publishes on September 12th, available online and wherever you buy your books.