What It Would Take to Build a City on Mars

Mars is the most Earth-like planet we can reach, which is not saying much. Its air is thin and mostly carbon dioxide, its surface is cold, and it has no global magnetic field to shield settlers from radiation. Still, engineers and dreamers keep sketching cities there. What would they need?

1. Air

Oxygen can be produced from the carbon dioxide atmosphere itself. NASA's MOXIE experiment aboard the Perseverance rover demonstrated the basic principle on the Martian surface. Scaling it up to support a town is the next challenge.

2. Water

Orbiters have found evidence of large amounts of water ice beneath the surface at mid and high latitudes. Mining it would supply drinking water, agriculture and, split into hydrogen and oxygen, rocket propellant.

3. Radiation

Without a thick atmosphere or magnetic field, the surface receives far more radiation than Earth. Proposals range from burying habitats under regolith to building inside lava tubes.

4. Dust

Fine dust gets into seals, coats solar panels and can rise in planet-wide storms. Any city needs dust-tolerant machines and power sources that keep working when the sky goes dark.

5. Distance

Launch windows between Earth and Mars open roughly every 26 months. A Martian city must be largely self-sufficient between supply runs — which brings us back to AI, robotics and local manufacturing.

None of these problems is solved yet. All of them are being worked on. That is what makes this frontier exciting to follow.