Mars Is Not Ready for Humans

While scientists are exploring the use
of microbes to revolutionize habitat con-
struction on Mars, big challenges persist

A Man on Mars Discussion Sequel
Exploring Biomineralization for Martian Construction

by Dr. Sarah Buckland-Reynolds

Mars has long been envisioned as humanity’s next frontier. Its rocky terrain and Earth-like axial tilt give it a deceptively familiar appearance, yet its reality is profoundly different: a thin atmosphere, intense radiation, and a barren regolith.

From Earth to Mars: a perspective on exploiting biomineralization for Martian construction (Khoshtinat et al, Frontiers in Microbiology 1 Dec 2025). This paper evaluates biomineralization (the process by which microbes precipitate minerals) as a promising pathway for constructing habitats directly from Martian soil.

The concept is compelling: engineered microbes could transform regolith dust into concrete-like building materials, generating oxygen as a byproduct, and contribute to closed-loop life-support systems. Yet, even amid these exciting advances, the findings underscore Mars’s intrinsic challenges: environmental extremes and resource limitations, that continue to hinder both sustaining human life and producing reliable construction materials on the Red Planet.

Scientific Findings: Biomineralization Pathways

Khoshtinat et al., ground their rationale in the “high cost and logistical complexity of transporting construction materials to Mars”. In an attempt to address limitations in the chemical composition of Martian soil, they explore the potential of biomineralization “as a low-energy, sustainable alternative to conventional construction methods, such as Portland cement and thermal sintering approaches proposed for lunar applications”.

One of the primary limitations highlighted in the paper is the composition of Martian regolith. Martian rock is rich in silica (~42–47%), alumina (~7–10%), iron oxides (~10–26%), and magnesium oxide (~6–9%), but notably deficient in calcium oxide (~5.7–6.9%). The authors note:

“This significant shortfall in CaO implies that in situ production of a true Portland cement analog on Mars is unlikely without external supplementation.”

To address this deficiency, they explored resilient microbes capable of thriving in harsh conditions while enabling calcium carbonate precipitation. Key microbial pathways include ureolysis (via Sporosarcina pasteurii, a ureolytic bacterium that hydrolyzes urea to produce carbonate ions) and photosynthesis (via extremophilic cyanobacteria such as Chroococcidiopsis). In a proposed co-culture system, Chroococcidiopsis could generate oxygen, secrete protective extracellular polymeric substances (EPS) to shield against UV radiation, and create a favorable microenvironment for S. pasteurii to precipitate minerals. While extremophiles like Chroococcidiopsis show remarkable resilience to simulated Martian stresses (e.g., desiccation, radiation, and low temperatures), the authors found that even these hardy strains face constraints in overall biomass production and metabolic rates under unmitigated Martian conditions.

Mars’ Intrinsic Constraints Remain Amidst Innovation

Despite the promising microbial pathways outlined, environmental constraints intrinsic to the Martian landscape continue to present major challenges for both the sustenance of life, as well as for efficient, large-scale construction. Among these key constraints include:

1. Chemical Deficiency

As the authors acknowledged, Martian regolith lacks sufficient calcium oxide, the cornerstone of cement. While microbes can precipitate calcium carbonate, the shortage of CaO means true Portland cement analogs cannot be produced in situ without external supplementation. This deficiency highlights Mars’ inherent limitations in naturally supporting robust, cement-like construction materials—even when innovative biomineralization methods are employed.

2. Environmental Hostility

Mars’ low gravity, extreme temperature swings, intense cosmic and solar radiation, and thin CO₂-dominated atmosphere would further impair the use of microbes in construction due to the profoundly hostile environment that severely limits microbial viability and activity essential for biomineralization-based construction. The thin atmosphere exposes the surface to high levels of radiation, while frequent freeze–thaw cycles and low-pressure further stress potential microbial agents. The article notes that microbial viability is markedly impaired under these simulated Martian conditions, with only modest proliferation possible when moisture and nutrients are artificially supplied.

In their words, the authors admit: “Simulated Martian conditions, low pressure, CO₂-rich atmosphere, and freeze–thaw cycles have been shown to markedly impair bacterial viability…. However, certain psychrotrophic microbes can exhibit modest proliferation when moisture and nutrients are present, with up to three times increase in viable cells over 7–14 days.”

This shows that even with the creation of ‘favourable’ conditions, constraints persist, revealing that Mars is fundamentally hostile to sustained microbial activity.

3. Gravity and Hydration Challenges

Mars’ environment poses a further challenge in the form of low gravity. Low gravity disrupts particle settling and hydration kinetics, leading to porous, weak structures for any structure erected in that environment. Comparing conditions in Earth versus Mars, the authors state that:

“Crystallization process experiments aboard the International Space Station revealed that microgravity suppresses sedimentation and bleeding, resulting in more uniform hydration but also in a 20% increase in porosity and larger pore sizes compared to Earth-based conditions, leading to weaker, more heterogeneous microstructures”

These microgravity-induced changes (higher porosity, altered pore distribution, and reduced structural integrity) would similarly affect microbially induced mineral precipitation on Mars, compromising the strength and durability of any bio-concrete or habitat material formed in situ.

4. Radiation and Temperature Extremes

The extremes in temperature and radiation that are characteristic of the Martian environment pose further constraints. The authors demonstrate that even microbes resistant to UV radiation, such as Chroococcidiopsis, require protective enclosures to survive. The need for pressurized, shielded bioreactors demonstrates that Mars cannot sustain microbial processes in open surface environments. In addition, its freeze–thaw cycles further disrupt enzymatic activity, limiting biomineralization to narrow windows of time.

5. Water Scarcity and Contamination

The lack of water on Mars poses one of the major constraints, as water is the most critical input for biomineralization. Although subsurface ice may exist, Martian water sources are contaminated with perchlorates (highly toxic salts that threaten microbial viability). Any use of such water would require extensive purification, adding significant complexity and cost. Consequently, Martian water is not readily usable, reinforcing the plantes unsuitability for sustaining life and construction processes.

Europa (top) compared to Earth and Mars.

Intelligent Design Perspective

The limitations faced by even the most resilient organisms to extremes on Mars underscore the unique suitability of Earth for habitation. Mars’ deficiencies, including chemical, environmental, gravitational, and hydrological extremes, reveal that it was not formed to sustain life. While microbes may temporarily assist human survival, the new simulations show that major constraints must be overcome to counter the planet’s intrinsic hostility. The very need for artificial enclosures, imported supplements, and robotic precision underscores that Mars fundamentally resists habitation.

The Uniqueness of Earth

While the vision of microbes constructing habitats on Mars is ingenious, it ultimately exposes the planet’s intrinsic constraints. Its regolith lacks key components, its environment undermines microbial viability, its gravity weakens structures, its radiation demands shielding, and its water is scarce and contaminated.

Even with microbial cooperation and advanced robotics, Mars cannot sustain life or produce building materials without extraordinary intervention. This reality underscores Earth’s uniqueness: a finely balanced, richly provisioned world, divinely designed for habitation. Mars may inspire exploration, but it ultimately testifies to the Creator’s wisdom in making Earth our true home.

As Scripture affirms in Isaiah 45:18: “He did not create it in vain, He formed it to be inhabited.” Earth was designed for habitation; Mars was not.

As we construct and inhabit buildings here on Earth, we should recognize the remarkable balance of conditions that make such activity sustainable. Earth reflects the intentionality of God in creating the universe, as Psalm 104:24 declares: “O Lord, how manifold are Your works! In wisdom You have made them all.”

Dr. Sarah Buckland-Reynolds is a Christian, Jamaican, Environmental Science researcher, and journal associate editor. She holds the degree of Doctor of Philosophy in Geography from the University of the West Indies (UWI), Mona with high commendation, and a postgraduate specialization in Geomatics at the Universidad del Valle, Cali, Colombia. The quality of her research activity in Environmental Science has been recognized by various awards including the 2024 Editor’s Award from the American Meteorological Society for her reviewing service in the Weather, Climate and Society Journal, the 2023 L’Oreal/UNESCO Women in Science Caribbean Award, the 2023 ICETEX International Experts Exchange Award for study in Colombia. and with her PhD research in drought management also being shortlisted in the top 10 globally for the 2023 Allianz Climate Risk Award by Munich Re Insurance, Germany. Motivated by her faith in God and zeal to positively influence society, Dr. Buckland-Reynolds is also the founder and Principal Director of Chosen to G.L.O.W. Ministries, a Jamaican charitable organization which seeks to amplify the Christian voice in the public sphere and equip more youths to know how to defend their faith.