Book Review: A City on Mars by Kelly and Zach Weinersmith

When people imagine Mars, they often see domes glinting under a pink sky, astronauts farming potatoes, or bustling colonies reminiscent of frontier towns. Kelly and Zach Weinersmith’s A City on Mars cuts through this romantic vision with wit and rigor, offering perhaps the most grounded—and sobering—exploration of what it would really take to build a city on the Red Planet.

The book is not a manifesto of optimism, nor is it a rejection of space settlement. Instead, it’s an audit: what do we actually know, and what do we desperately not know, about human habitation off-Earth?

Summary of the Book

The Weinersmiths begin by surveying the history of human fascination with Mars settlement and the current wave of enthusiasm driven by private space companies. From there, they meticulously unpack the scientific, technical, legal, and social challenges of establishing a permanent community on Mars.

• Radiation & Health: Mars offers little magnetic shielding, so settlers will be exposed to high radiation levels, with uncertain long-term health impacts.

• Gravity & Biology: We know almost nothing about the effects of Martian gravity (38% of Earth’s) on human development, reproduction, or long-term health.

• Habitability & Life Support: While closed-loop life support systems like MELiSSA and EDEN ISS have made progress, they remain experimental, and we lack the ability to scale them reliably.

• Law & Governance: The Outer Space Treaty leaves vast gaps in how settlements would be managed, resourced, or even owned.

The book repeatedly stresses that enthusiasm has outpaced evidence. We are not yet ready for a Mars city—because the research foundation has not been built.

Key Conclusions on Missing Research

The Weinersmiths identify critical areas where data is absent or wholly inadequate:

1. Habitats & Protection

   • Lack of real-world testing of habitats against Mars-like hazards (radiation, dust infiltration, micrometeoroid shielding).

   • No large-scale experiments on inflatable or regolith-based shielding structures.

2. Human Health & Biology

   • Unknowns about fertility, pregnancy, and child development in partial gravity.

   • Long-term psychological and physiological effects of underground living in isolated environments.

3. Life Support & Food

   • Insufficient maturity of closed-loop ecological systems.

   • Minimal field testing of underground or cave-based farming techniques.

4. Society & Law

   • No tested models for governance, conflict resolution, or ownership of space-based resources.

Plan R Architects: Taking the Challenge Forward

At Plan R Architects, we see A City on Mars not as discouragement but as a research roadmap. By clearly identifying the gaps, the Weinersmiths point to where innovation is most urgently needed.

Our focus is on habitat design and adaptation to natural structures such as lunar lava tubes and Martian caves. These spaces offer natural radiation protection and reduce the mass that must be launched from Earth. Building on the lessons highlighted in the book, we propose a research agenda that includes:

• Inflatable and modular habitat systems tested in Earth caves as analogs for lava tubes.

• Underground farming trials with automated and robotic support to study sustainable food production in low-light, closed environments.

• Psychological and social research into long-term underground living, including effects of light, confinement, and isolation.

• Integration of robotics and AI for habitat construction and maintenance, reducing human exposure to risk.

By tackling these lines of inquiry, Plan R seeks to transform the unanswered questions into tested solutions, laying the groundwork for true off-Earth habitation.

Final Thoughts

• A City on Mars* is not a book of blueprints but of reality checks. Kelly and Zach Weinersmith remind us that the dream of Martian cities is still more aspiration than plan. Yet, by exposing the gaps, they invite architects, scientists, and engineers to turn imagination into research and research into reality.

At Plan R Architects, we accept that invitation. The first Martian settlers may not walk into shining domes, but into carefully designed habitats carved into the planet’s ancient caves. Like our ancestors who sought safety in Earth’s caves, we too may find that the path to the future begins underground.

🔹 Punch List: Research Priorities from A City on Mars

• Test inflatable/regolith habitats in Earth caves.

• Study long-term health impacts of partial gravity.

• Develop underground automated farming systems.

• Advance closed-loop ecological life support.

• Explore governance models for extraterrestrial communities.