Link to the code: Zae-Project / arkspace-core

Becoming Martian: How Living in Space Will Change Our Bodies and Minds

Evolutionary biology moves slowly. The human body is the product of roughly 300,000 years of selection in one gravitational environment, under one atmospheric composition, exposed to one radiation level. A Mars settlement does not give evolution time to catch up. The biological changes that space travel forces on the human body occur within weeks, and permanent habitation would impose selection pressures unlike anything Homo sapiens has encountered before.

Scott Solomon’s Becoming Martian: How Living in Space Will Change Our Bodies and Minds, published in February 2026, approaches this transformation through the lens of evolutionary biology rather than aerospace medicine. Solomon is not primarily interested in what happens to the astronauts already in orbit. He is interested in what happens to the descendants of settlers after generations on Mars, and what that trajectory means for the broader question of whether permanent off-Earth habitation is biologically as well as technically achievable.

The biological picture he assembles has immediate consequences for how orbital infrastructure must be designed. The monitoring, medical response, and autonomous health management systems required for a Mars settlement are not afterthoughts. They are critical infrastructure.

The Physiology of Microgravity Exposure

The baseline data on what space does to the human body comes primarily from the International Space Station and the Russian Mir program. These datasets are extensive but have a significant limitation: the longest continuous stays in microgravity, around 438 days (Valeri Polyakov, 1994-95), fall well short of the minimum 180-day transit time for a Mars mission, let alone the years of surface habitation that would constitute permanent settlement.

The documented effects of long-duration microgravity exposure include fluid redistribution toward the upper body, elevating intracranial pressure and causing measurable changes in visual acuity. Bone density loss proceeds at roughly 1-2% per month in loaded skeletal regions if countermeasures are insufficient, compared to the roughly 1% per decade loss of aging on Earth. Muscle atrophy occurs alongside cardiovascular deconditioning as the heart adapts to pumping blood without gravitational assist. Immune function shows alterations that remain poorly characterized at multi-year durations.

Solomon emphasizes that Mars gravity, at 0.376g, is not microgravity. The Red Planet does provide some resistance to fluid shifts and bone loss. But it is well below the 1g for which human physiology was optimized, and it is not clear which effects of microgravity transit will reverse on Mars arrival, which will persist, and which will compound over decades of low-gravity living.

The data simply does not exist yet. No human has spent meaningful time at 0.376g. The short-duration centrifuge studies and brief parabolic flight experiments that approximate partial gravity do not produce the longitudinal data needed to assess permanent habitation effects.

Radiation: The Constraint That Infrastructure Must Address

Of all the biological challenges Solomon documents, radiation is the most immediately relevant to infrastructure design. Earth’s magnetic field and atmosphere reduce naturally occurring radiation to biologically manageable levels. Mars has neither a global magnetic field nor a substantial atmosphere, which means surface radiation is 40-50 times higher than typical Earth-surface exposure.

Galactic Cosmic Rays (GCRs) are the primary long-term concern. These high-energy particles, originating from supernovae and other high-energy astrophysical events outside the solar system, penetrate virtually any shielding that could be practically deployed in a spacecraft or habitat. High-Z (high atomic number) GCR particles interact with shielding material and produce secondary particle showers that can be more damaging than the primary radiation.

The NASA acceptable career radiation dose limit for astronauts is based on a 3% lifetime excess risk of fatal cancer. For a three-year Mars mission with current shielding technology, NASA estimates radiation exposure near or exceeding that limit. For permanent habitation, lifetime exposure would far exceed what crew health policies currently permit.

Solomon is not pessimistic about this. He documents active research into radio-protective compounds, underground or lava tube habitats that use Martian rock as natural shielding, and the possibility that genetic selection or therapeutic intervention could raise radiation tolerance in Mars-born generations. But he is clear that the current state of radiation medicine does not yet support confident projection of what long-duration exposures produce in terms of cancer incidence, neurological effects, or heritable genetic damage.

The implication for orbital infrastructure from the perspective of distributed satellite networks is that any Mars communication and support architecture must include a specialized layer for continuous crew health monitoring. Radiation dosimeters, biological markers, and longitudinal health data must flow constantly between Mars habitat sensors and medical databases, wherever those databases are maintained. Given the communication delay, the analysis and response must happen autonomously at the settlement end.

The Psychology of Isolation at Interplanetary Distances

Solomon’s treatment of psychological effects is less detailed than his biology chapters, but the infrastructure implications are substantial. Research from Antarctic winter-over crews, submarine crews, and ISS long-duration missions documents the psychological toll of isolation, confinement, and communication delay with the broader social world.

Mars settlers would face the most extreme version of these conditions ever experienced. The 6.2 to 44.4 minute communication delay with Earth does not merely slow down information exchange; it changes the psychological character of communication entirely. Real-time conversation becomes impossible. Text and video logs replace dialogue. The spontaneity of social contact, which is central to how humans maintain psychological health at distance, is structurally eliminated.

Research into crew dynamics for long-duration missions, including studies from the Mars-500 isolation simulation in Moscow and the Antarctic Concordia station (cited as the closest Earth-analog for Mars psychological conditions), identifies specific risks: interpersonal conflict escalation without communication relief valves, depression driven by loss of autonomy and privacy, and the specific psychological load of knowing that any emergency is entirely self-contained.

The autonomous computing infrastructure being validated by current spacecraft AI programs will need a psychological support dimension. Therapeutic AI systems capable of conducting structured psychological support sessions, flagging anomalous behavioral patterns in crew monitoring data, and managing interpersonal mediation protocols have been discussed in NASA’s Human Research Program since 2020. The biological sensors and behavioral monitoring infrastructure for a permanent Mars settlement would constitute a continuous data stream requiring local processing and response capability.

Evolutionary Pressures on Mars-Born Generations

The section of Solomon’s book that has drawn the most attention from both scientists and general readers addresses what happens not to the first generation of settlers but to their descendants. This is where the book’s title becomes most literal.

Natural selection operates on variation. A founding settler population carries genetic diversity from Earth, but the specific pressures on Mars, radiation tolerance, altitude hypoxia adaptation (Mars’s atmospheric pressure is less than 1% of Earth’s), cold tolerance, low-gravity skeletal and cardiovascular optimization, and perhaps altered immune contexts, would over many generations begin selecting for variants that are better suited to the Martian environment and less suited to returning to Earth.

Solomon is careful to distinguish this from science fiction scenarios of deliberate genetic engineering or rapid transformation. He is describing standard population genetics operating on timescales of centuries and millennia. The point is that Mars settlers are not simply humans temporarily transplanted to a new location. If settlement is permanent and transgenerational, the population will diverge.

The governance, ethical, and political implications of this divergence are beyond the scope of a technical infrastructure analysis. But the monitoring infrastructure implication is clear: long-term biological and genetic data collection from Mars settler populations constitutes one of the most scientifically valuable datasets in human history, and the communication architecture between Mars and Earth must be capable of supporting it.

What This Means for Orbital Infrastructure Design

Solomon’s analysis points to several specific infrastructure requirements that current programs address only partially.

Biomedical monitoring at scale. A permanent Mars settlement requires continuous biometric monitoring for all residents, not just astronauts. The computing infrastructure for processing and responding to that data locally is more demanding than anything deployed in current space medicine programs. Edge AI on satellites, currently validated for Earth observation applications, provides a technical precedent for running complex inference workloads on constrained hardware in space environments.

Autonomous medical response. Given the communication delay, a medical emergency on Mars requires local diagnostic and treatment decision capability without Earth consultation. The AI systems required for this go substantially beyond current autonomous health monitoring. They need to integrate real-time imaging, lab analysis, psychological assessment, and treatment protocol execution in a fully autonomous chain.

Radiation habitat shielding validated for multi-decade exposure. The on-orbit servicing infrastructure developing in 2026 demonstrates increasing capability for complex operations in space environments. The same construction and maintenance capability will be needed for Mars surface habitat modifications driven by evolving understanding of multi-decade radiation exposure effects.

Communication infrastructure that supports the biological data pipeline. The bandwidth required for continuous biological monitoring of a settlement population is substantial. The optical inter-satellite link technology advancing in 2026 provides the backbone for high-bandwidth Earth-Mars data relay, but the relay satellite infrastructure between Earth and Mars does not yet exist. It requires a dedicated cislunar and interplanetary relay constellation.

Path Forward

Becoming Martian is not a dystopian book. Solomon documents real challenges, but he also documents the active research in radiation medicine, telemedicine AI, autonomy, and habitat design that addresses each of them. What he makes clear is that human biology is the most constraining parameter in Mars settlement planning, not launch economics or propulsion.

The biological constraints drive infrastructure requirements that are not being designed at scale today. The monitoring, medical response, and communication architectures needed for a biologically healthy Mars settlement population are substantially more demanding than what current crewed spaceflight programs require. The future spacefaring society that Carberry and Zucker’s 2026 edited volume describes depends on solving the biological challenges Solomon maps, and that solution is as much a systems engineering problem as a medical one.

Mars is not the Moon. The biology that makes it harder also makes it more consequential. A permanent human presence on Mars represents an evolutionary branch point in the history of the species, and the satellite and orbital infrastructure that supports it will determine whether that branch point leads somewhere viable.

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