Where would humans actually live on Mars?

Editorial status: original English article by David Salvan’s Delta-Sierra project. Scientific claims are linked to institutional sources; prospective settlement choices are identified as analysis rather than fact.

Habitat reality

Why the first Mars colony will not be a transparent city under glass

A large transparent dome is visually compelling and structurally demanding. It must hold an Earth-like internal pressure against an almost vacuum-like exterior across a vast area. Every square meter experiences outward force. Transparent materials also provide limited shielding against radiation and are vulnerable to impact, thermal cycling and dust abrasion. Early settlements will therefore favor smaller pressure vessels with inspectable walls and external shielding.

The central principle is separation of functions. The pressure shell holds atmosphere. External mass—regolith, water, stored supplies or dedicated shielding—reduces radiation. An outer protective layer manages dust, temperature and impacts. Interior partitions control fire, smoke, noise and privacy. No single material should be expected to perform every task perfectly.

Radiation sets the geometry

Mars lacks Earth’s thick atmosphere and global magnetic protection. Curiosity’s Radiation Assessment Detector measured a surface environment dominated by galactic cosmic rays and vulnerable to solar particle events. NASA estimates based on the cruise and surface measurements have illustrated total exposure near one sievert for a representative round-trip mission, though actual risk depends on mission duration, solar activity, shielding and biological assumptions.

Shielding is therefore not optional. Hydrogen-rich materials such as water and some polymers are useful against certain radiation components. Regolith is abundant and does not need to be launched from Earth. A practical habitat might place water tanks and food stores around sleeping quarters, then cover the external structure with compacted soil or bags filled robotically.

Every settlement also needs a more heavily shielded storm shelter for solar events. It should be reachable quickly, contain independent communications and life support, and double as a normal-use space so that it is maintained rather than forgotten.

Surface, semi-buried or fully underground?

Surface modules are easiest to land, inspect and expand. Their weakness is exposure. Semi-buried modules preserve access while gaining shielding. They may be the most realistic early compromise: land a certified pressure vessel, connect it, verify it and then place regolith around and above it using robotic equipment.

Fully excavated caverns can provide excellent shielding and thermal stability but require heavy equipment, geological certainty and safe lining. Natural lava tubes are often proposed because orbital imagery suggests volcanic voids exist on Mars. Yet a void is not automatically a habitat. Its geometry, stability, access, contamination and distance from useful resources must be mapped before humans rely on it. Early settlers are more likely to use engineered, covered modules than to move immediately into an unknown cave.

The pressure shell must remain visible to maintenance

Burying a habitat can hide leaks, corrosion or structural movement. Designers need inspection corridors, sensors and accessible joints. The regolith layer should not be dumped directly onto delicate penetrations. Utilities should pass through standardized service nodes that can be isolated and replaced.

Inflatable volumes offer high internal volume for launch mass, while rigid modules offer robust interfaces and known structural behavior. Hybrid designs can place an inflatable living volume inside a protective frame or excavated shell. Whatever the material, the structure must tolerate repeated pressure cycles, temperature change and accidental local damage.

Dust control begins outside the airlock

Martian dust is fine, abrasive and chemically significant. It can damage seals, bearings and optical surfaces and may present inhalation hazards. NASA was still refining preliminary crew exposure limits for Martian dust in 2026, a reminder that the health problem is not fully characterized.

A normal terrestrial-style airlock that brings dirty suits indoors would contaminate the habitat. Suitports, where a suit remains outside and the astronaut enters through its rear, can reduce transfer. Equipment cleaning areas, electrostatic or mechanical removal, replaceable filters and dirty-to-clean pressure zoning are all part of the habitat rather than optional housekeeping.

Interior design is a survival system

People living for months or years in confined volume need acoustic control, privacy, varied lighting, visual depth and places not dedicated to work. CHAPEA and other analog studies examine behavioral health precisely because technical survival is not enough. Chronic sleep disruption, unresolved conflict or cognitive fatigue can produce operational errors.

Private cabins should be small but truly private. Shared spaces should allow communal meals, exercise and informal conversation. Light cycles should support circadian rhythm. Windows may be small, shielded or replaced partly by high-resolution external views, but residents still need a perceptible connection to place. Plants can contribute psychological value even when they provide only a small fraction of calories.

A settlement should be a network of compartments

One giant pressurized volume is efficient until it leaks or burns. A safer settlement uses multiple zones connected by closable passages. Sleeping quarters, medical care, laboratories, farms, workshops and storage should not share every atmosphere loop. Fire loads and toxic industrial processes need distance from residential areas.

At least two protected routes should connect critical zones. Residents should be able to shelter in place if a corridor is lost. External emergency paths, suits and rover access provide another layer. This arrangement may look less elegant than a single dome, but cities on Earth also separate hazardous industry, utilities and housing for good reasons.

Habitat growth should preserve repairability

Expansion is not simply attaching another module. New volumes change airflow, power demand, evacuation routes and structural loads. Interfaces should be standardized from the beginning. A service spine can carry power, data, water and ventilation while allowing branches to be isolated. New districts can later connect through pressurized transit tubes or short rover routes.

The first habitat is therefore a seed of urban form. Its most important architectural feature may be the ability to accept change without forcing the entire settlement to shut down.

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