Practicing for Mars: A History of Earth-Based Analog Missions

Rehearsing for the Red Planet

Sending human beings to Mars represents an endeavor of monumental complexity, a journey that pushes the boundaries of technology, endurance, and human psychology. Before astronauts take their first steps on the red planet, every conceivable aspect of the mission must be tested, rehearsed, and refined. This meticulous preparation doesn’t happen in space; it happens here on Earth, in remote and extreme environments that serve as stand-ins for the Martian landscape. These terrestrial locations are known as Mars analog environments, and the missions conducted within them are fundamental to the future of human space exploration.

An analog mission is a simulation that takes place in a location with physical or operational similarities to an extreme space environment. The primary purpose is to gather data on the strengths and weaknesses of planned technologies, operational procedures, and human performance before committing to a multi-billion dollar, high-risk spaceflight. For a location to serve as a Mars analog, it needs to share at least one relevant characteristic with the red planet. These can range from geology and mineralogy to environmental conditions like extreme aridity, frigid temperatures, or high levels of ultraviolet radiation.

However, no single location on Earth can perfectly replicate Mars. The Martian atmosphere is a thin, carbon dioxide-dominated near-vacuum, with pressures less than 1% of Earth’s. Its surface temperatures can swing wildly within a single day, and its soil is saturated with oxidizing compounds like perchlorates, making it toxic to most known life. Because of these differences, terrestrial analogs are necessarily partial simulations. This has led to the use of a portfolio of different analog sites, each chosen to test a specific aspect of a Mars mission. Some sites are chosen for their geological resemblance, others for their extreme isolation, and still others are engineered environments designed to test specific technologies or crew dynamics.

The history of these analog missions reveals a maturing understanding of the challenges ahead. The concept of “fidelity”—the degree to which a simulation resembles reality—has evolved significantly. Early research focused primarily on geological fidelity, seeking out desolate landscapes like the Antarctic Dry Valleys to answer the question, “What was ancient Mars like?” This was a process of passive observation, studying a place to understand another.

With the turn of the century came a new focus on operational fidelity. The construction of the first enclosed habitats, such as the Flashline Mars Arctic Research Station and the Mars Desert Research Station, marked a deliberate shift from observation to active simulation. The question changed to, “How will we live and work on Mars?” This introduced the human as a variable to be tested, complete with spacesuits, airlocks, and mission protocols.

More recently, programs have prioritized psychological fidelity. Missions like the Hawaii Space Exploration Analog and Simulation (HI-SEAS) isolated crews for up to a year, enforcing communication delays to mimic the vast distance between Earth and Mars. Here, the central question became, “How will our minds endure the journey?” Finally, the latest generation of analogs, like NASA’s CHAPEA, is adding a new layer of infrastructural and logistical fidelity, using 3D-printed habitats and focusing on year-long resource management to ask, “How can we build a sustainable presence on Mars?” This progression from geology to operations, psychology, and sustainability charts the course of our preparation, showing how, over decades, we have learned which questions are the most important to ask.

The Pioneers: Early Steps in a Mars-Like World

The genesis of Mars analog research lies in the scientific quest to understand the red planet’s past. Before humans could be simulated on Mars, scientists first had to find places on Earth that mirrored its cold, dry, and seemingly lifeless conditions. This search led them to the most remote continent on the planet, laying the geological groundwork for the operational simulations that would follow.

Geological Forerunners: The Antarctic Dry Valleys

Long before the first simulated habitat was built, scientists identified the McMurdo Dry Valleys (MDV) in Antarctica as the best terrestrial approximation of the contemporary Martian surface. This hyper-arid, hypo-thermal polar desert, considered a valuable analog since the Viking missions of the 1970s, shares a remarkable number of features with Mars. Both landscapes are characterized by extreme cold, pervasive shallow-buried ice, and similar processes of chemical weathering on rocks and soil.

The MDV became a natural laboratory for testing theories about Mars’s climatic history. Robotic missions had revealed vast networks of valleys on Mars, suggesting the past presence of liquid water. A key debate emerged: was early Mars “warm and wet,” with a thick atmosphere and flowing rivers, or was it “cold and icy,” with water appearing only ephemerally? Research in the MDV provided compelling evidence for the latter. Scientists observed that despite mean annual air temperatures between -14 °C and -30 °C, ephemeral streams and ice-covered lakes could still form from the seasonal melting of glaciers and snowpacks. This demonstrated that a planet with average temperatures well below freezing could still produce the kind of fluvial features seen on Mars, supporting the model of a cold and icy early Mars punctuated by brief periods of melting.

Furthermore, the discovery of life in this extreme environment had profound implications for astrobiology. Resilient, metabolically complex ecosystems dominated by microbes, algae, and mosses were found thriving in the MDV, fueled by the brief seasonal meltwater and abundant summer sunlight. These organisms, surviving in conditions previously thought to be sterile, provided a powerful model for how life might have persisted on Mars, guiding the development of strategies and instruments to search for biosignatures in similarly harsh environments. The work in Antarctica was foundational, providing the geological and biological context upon which all subsequent human-centric simulations would be built.

The First Habitats: The Mars Society’s Vision

The late 1990s marked a pivotal change in analog research. The focus began to shift from passively studying Mars-like environments to actively simulating human exploration within them. This transition was championed by the Mars Society, an advocacy group established in 1998 with the goal of preparing for human missions to the red planet. Their vision was to create dedicated research stations where crews could live and work under realistic mission constraints, a concept that gave birth to the world’s first Mars analog habitats.

The Flashline Mars Arctic Research Station (FMARS) was the first of these pioneering facilities. Established in 2000 on Devon Island in the Canadian High Arctic, FMARS was strategically placed near the Haughton impact crater, a site with a striking geological resemblance to Mars. From its first field season in 2001, FMARS hosted crews of 6-7 people in its cylindrical habitat for missions that typically lasted a month, with one crew completing a 100-day stay. The research conducted was groundbreaking for its time. Crews, wearing prototype spacesuits, deployed seismic sensors to test techniques for detecting subsurface water—a vital resource for future explorers. They also ran experiments to optimize the collaboration between the field crew and a remote science team on “Earth,” helping to define efficient methods for exploration under the communication delays inherent in a real Mars mission. FMARS was also a laboratory for the human experience, with studies examining the psychological effects of isolation and confinement.

Building on the FMARS model, the Mars Society established the Mars Desert Research Station (MDRS) in the Utah desert in 2001. While FMARS was more isolated, the Utah location offered a strong geological analog that was more accessible, allowing for a more continuous schedule of missions. Since its inception, MDRS has hosted over 270 crews, making it the longest-running and largest Mars surface simulation facility on Earth. The research at MDRS has been heavily focused on field science and operations. Early crews developed techniques for detecting methane—a potential biosignature—in desert soils and made the surprising discovery of methanogens, microbes that were not expected to thrive in such an environment. This finding lent support to the possibility of microbial life on Mars and demonstrated that crew members on a simulated spacewalk could successfully detect such signs of life.

The creation of FMARS and MDRS represented a conceptual leap. It was an acknowledgment that the human was not just an observer but a complex variable that needed to be tested. By introducing the constraints of habitat living, spacesuit operations, and mission protocols, these stations gave birth to operational analog research, laying the foundation for the more complex and psychologically focused simulations that would follow.

The Modern Era: Major Analog Programs and Their Discoveries

Building on the foundations laid by the early geological studies and the first habitats, the modern era of analog research has seen the rise of large-scale, multi-disciplinary programs. These projects have deepened our understanding of Mars exploration by creating increasingly sophisticated simulations that integrate science, technology, and the human element. Each major program has developed a specialized focus, contributing unique pieces to the puzzle of how to successfully live and work on another world.

The Haughton-Mars Project (HMP): Where Geology Meets Robotics

Located on Devon Island in the Canadian Arctic, the Haughton-Mars Project (HMP) is centered around the 23-million-year-old Haughton impact crater. The site is often described as “Mars on Earth” due to its polar desert climate, barren rocky terrain, and geological features that bear an uncanny resemblance to those on Mars. The project, which began in 1997, combines fundamental scientific research with the development of exploration technologies and strategies.

A primary scientific goal of HMP is to use the crater as an analog for understanding Martian geology and astrobiology. Researchers have used ground-penetrating radar and seismic surveys to image the subsurface permafrost layer, providing insights into how similar techniques could be used on Mars to search for water ice. The project is also a critical testbed for technology. It has served as a proving ground for robotic drills, prototype spacesuits, and rovers. This testing has yielded tangible results, including the development of rover wheel designs that prevent vehicles from sinking into soft sand and significant improvements in spacesuit ergonomics. One notable innovation tested at HMP is the “suitport,” a system that allows an astronaut to dock their spacesuit to the exterior of a rover and enter it directly, which minimizes the transfer of hazardous Martian dust into the vehicle and saves valuable time.

Perhaps one of HMP’s most significant contributions has been its work on quantifying the value of human explorers. Through a series of controlled field tests, researchers compared the scientific productivity of a spacesuited geologist with that of a tele-operated robotic rover controlled from a distance. The early results were striking, implying that a human on-site was one to two orders of magnitude more efficient at geological investigation than a remotely operated robot. This provided some of the first hard data to support the argument for sending humans, not just robots, to Mars. HMP has also conducted detailed studies on the complex logistics required to support a remote exploration base, tracking every class of supply and analyzing the efficiency of the transportation network. This research revealed that Extravehicular Activities (EVAs), or spacewalks, rarely proceed exactly as planned, often due to impassable terrain, highlighting the need for real-time re-planning tools for future explorers.

The Mars Desert Research Station (MDRS): A Laboratory for Field Operations

The Mars Desert Research Station (MDRS) in Utah has become the workhorse of analog research. As a long-running and continuously operated facility, it provides a platform for a steady stream of crews to conduct field science and hone operational procedures in a high-fidelity Mars-like environment. The campus itself has expanded over the years to include the main two-story habitat, a greenhouse (GreenHab) for cultivation experiments, the Musk Observatory for astronomical work, a science dome, and an engineering pod.

Research at MDRS is heavily oriented toward field geology and biology. Crews venture out on simulated EVAs to study the surrounding desert, which serves as a geological proxy for Mars. A major focus is the study of extremophiles—organisms that thrive in harsh conditions. This includes searching for and characterizing endoliths, which are microbes that live inside rocks, shielded from the harsh surface environment. This research is guided by a key principle: projects must be something that can only be accomplished in an analog setting, not in a conventional laboratory, ensuring the simulation provides unique scientific value.

The true strength of MDRS lies in its dedication to operational realism. Crews live for weeks at a time under full simulation constraints. They must don cumbersome spacesuit simulators for any activity outside the habitat, manage strictly limited resources like water and shelf-stable food, and contend with the daily realities of equipment maintenance. The mission reports from over two decades of operations provide an unparalleled database on the challenges of maintaining a remote outpost. These reports are filled with the kinds of mundane but critical problems that will dominate life on Mars: failing power systems, including solar battery banks that don’t hold a charge and generators with persistent oil leaks; constant vehicle maintenance; and the never-ending battle against dust infiltration. These “failures” are not setbacks; they are a primary research output, providing essential data for engineers designing the robust and repairable systems that will be needed for a real Mars mission. Through this relentless cycle of use, failure, and repair, MDRS contributes directly to mission planning by testing everything from EVA protocols and crew scheduling systems to the psychological effects of fieldwork on crew members.

Hawaii Space Exploration Analog and Simulation (HI-SEAS): The Human Dimension

While HMP and MDRS focused heavily on geology and field operations, the Hawaii Space Exploration Analog and Simulation (HI-SEAS) program was created to tackle what may be the most complex variable of all: the human mind. Located on the barren volcanic slopes of Mauna Loa in Hawaii, a site chosen for both its geological similarity to Mars and its profound isolation, HI-SEAS was designed primarily to study crew psychology and performance on long-duration missions.

The program’s defining feature has been its commitment to long-duration missions. HI-SEAS has successfully run missions of four, eight, and a full twelve months, providing an unprecedented amount of data on how small crews function under the immense stress of prolonged isolation and confinement. To achieve a high degree of psychological fidelity, the missions incorporate a crucial stressor: a 20-minute communication delay each way between the crew and “Mission Support”. This delay makes real-time conversation impossible, forcing the crew to become highly autonomous in their work and problem-solving, just as they would be on Mars.

The psychological findings from HI-SEAS have been illuminating. Researchers track crew cohesion, morale, stress levels, and conflict resolution strategies throughout the missions. The data has revealed distinct phases of psychological adaptation. An initial period of excitement and positive stress (“eustress”) often gives way to a challenging middle period marked by boredom, frustration, and increased potential for conflict. This aligns with the “third-quarter phenomenon” observed in other isolated environments, where morale tends to dip after the mission’s halfway point.

Just as importantly, HI-SEAS has been a testbed for effective coping mechanisms. Crews that have succeeded have demonstrated the importance of creating structure and meaning in a monotonous environment. Successful strategies include making meals special events, experimenting with recipes using shelf-stable ingredients, maintaining personal and group rituals like movie nights, journaling to process stress, and recognizing the immense psychological benefit of EVAs—simply “going outside,” even in a bulky suit, provides a powerful boost to morale. The lessons from HI-SEAS are clear: for a long-duration mission to succeed, the psychological health of the crew must be treated as a critical system, engineered and maintained with as much care as any life support machine.

A World of Analogs: Specialized Environments

Beyond the major, long-term habitat-based programs, a diverse array of specialized analog environments are used to investigate specific questions that are difficult to address elsewhere.

Underwater Environments: The premier example is NASA’s Extreme Environment Mission Operations (NEEMO). This project sends astronauts to live for weeks at a time in the Aquarius undersea laboratory off the coast of Florida. The unique advantage of the underwater environment is its ability to simulate reduced gravity. By carefully adjusting the buoyancy of the “aquanauts,” engineers can make them effectively weigh the same as they would on the Moon (one-sixth of Earth’s gravity) or Mars (about 38% of Earth’s gravity). This allows for high-fidelity testing of EVA tools, spacewalk techniques, and crew coordination in a partial-gravity setting, something that is impossible to sustain for long periods on the surface.

Volcanic Terrains: The volcanic landscapes of Hawaii, Iceland, and Idaho’s Craters of the Moon National Monument serve as crucial analogs for the volcanic plains of Mars and the Moon. These sites are used to train astronauts in field geology, teaching them how to interpret volcanic landforms and select valuable rock samples. They are also essential for testing scientific instruments, such as spectrometers, designed to analyze the composition of volcanic rocks that rovers like Perseverance are currently exploring on Mars. Lava tubes—caves formed by flowing lava—are of particular interest, as they could provide future human explorers with natural shelters from radiation and extreme temperatures.

Caves and Subsurface Environments: The surface of Mars is bathed in harmful radiation. This has led scientists to consider the deep subsurface as a potential refuge for past or even present-day life. To study these possibilities, researchers turn to unique terrestrial analogs. Movile Cave in Romania, for example, has been sealed off from the outside world for over 5.5 million years, hosting a unique ecosystem that thrives on chemical energy in the absence of sunlight. Similarly, researchers have ventured kilometers deep into mines like the Mponeng gold mine in South Africa to study bacteria that live completely independent of the sun’s energy, providing a model for how life could exist deep within the Martian crust.

This portfolio approach, leveraging the unique strengths of desert, polar, volcanic, underwater, and subsurface analogs, is essential. Each environment provides a different lens through which to view the challenges of Mars exploration, ensuring that when humans finally go, they are as prepared as possible for the realities that await them.

Comparison of Major Mars Analog Programs

The following table provides a comparative summary of the primary analog programs, highlighting their unique locations, research focus, and key contributions to Mars exploration. This illustrates the necessity of a diverse portfolio of simulations to address the multifaceted challenges of sending humans to another planet.

The Human Element: Psychology in Isolation

While engineering and geology present formidable challenges, the data from decades of analog research consistently points to the human element as one of the most complex and critical systems in any long-duration mission. A spacecraft can be designed for near-perfect reliability, but its human crew is subject to the subtle and powerful pressures of psychology, social dynamics, and the stress of confinement. Analog missions, particularly those focused on long-duration isolation, have become indispensable laboratories for understanding and mitigating these human-centric risks.

The primary psychological stressors of a Mars mission are well-documented through these simulations: profound isolation from family and society, confinement in a small habitat, the monotony of daily routines, chronic stress, and disrupted sleep cycles. The environment itself is hostile and unforgiving, which can lead to anxiety, depression, and a decline in cognitive function over time. The vast distance from Earth introduces another unique stressor: communication delays. The up-to-22-minute lag each way makes real-time conversation with mission control or loved ones impossible, deepening the sense of isolation and forcing the crew to operate with an unprecedented level of autonomy. This autonomy is a double-edged sword; while it fosters independence, it also places the full burden of emergency response and daily problem-solving squarely on the shoulders of the small, isolated crew.

Within this pressure-cooker environment, crew cohesion and conflict management become paramount. Research has shown that conflict is not just possible, but inevitable on a long mission. Analog studies have helped to distinguish between two types of conflict: task-related conflict, which involves disagreements about how to perform a job and can sometimes be productive by generating new ideas, and interpersonal conflict, which stems from personal clashes and is almost always destructive to team morale and performance. When interpersonal tensions are not resolved, they can fester. One documented coping mechanism is displacement, where a crew directs its frustration outward, blaming a remote and unseen Mission Control for scheduling problems or a perceived lack of support. This can poison the critical relationship between the crew and their ground support team.

The data from long-duration analogs like HI-SEAS has revealed that the greatest psychological threat may not be a single, dramatic crisis, but rather the slow, corrosive effect of the mission’s daily grind. Astronauts are selected for their resilience and are highly trained to handle acute emergencies. However, it is the cumulative weight of boredom, routine, and minor, unresolved annoyances that can wear down even the most robust individuals. This is exemplified by the “third-quarter phenomenon,” a well-documented trend in isolated groups where morale and mood tend to hit a low point after the mission’s halfway mark, once the initial excitement has faded but the end is still not in sight. HI-SEAS data from its year-long mission supported this, suggesting that adverse psychological conditions were most likely to develop after about six months.

This understanding has shifted the focus of psychological support. It is not enough to prepare for emergencies; one must actively manage the daily mental well-being of the crew. The coping strategies identified in analog missions are telling: they are often “soft” solutions focused on maintaining routine and finding moments of novelty. Successful crews establish rituals like weekly movie nights, make an effort to prepare special meals, keep personal journals to process their thoughts, and use regular exercise to combat stress. Recognizing this, future mission planning now incorporates the development of autonomous support systems, such as automated psychotherapy programs and self-guided stress management tools, that can help astronauts manage their mental health without relying on real-time guidance from a distant Earth.

The Toolkit: Technology and Operations Under Simulated Conditions

Analog missions provide more than just scientific and psychological insights; they are the proving grounds where the tools and techniques of planetary exploration are forged. By repeatedly testing hardware and procedures under simulated conditions, engineers and mission planners can identify weaknesses, refine designs, and develop robust operational protocols. This iterative process, moving from the drawing board to the field and back again, is how the abstract challenges of a Mars mission are translated into tangible, reliable solutions.

Roaming the Land: Rovers and Spacesuits

The ability of astronauts to move across and work on the Martian surface will depend entirely on the performance of their vehicles and spacesuits. Analog sites offer the perfect opportunity to test these critical systems in challenging, Mars-like terrain. At the Haughton-Mars Project, for example, testing of prototype rovers in sandy and rocky areas led directly to design improvements that prevent wheels from sinking, a seemingly simple problem that could be catastrophic for a stranded crew on Mars. Analogs are also used to develop human-robot teaming strategies, such as using aerial drones to perform reconnaissance and help plan the safest and most efficient routes for EVAs.

Spacesuits are subjected to rigorous testing to evaluate their mobility, dexterity, and durability. Crews at MDRS have conducted studies on the abrasive wear of glove materials from contact with sand and rock, providing vital data for developing more durable fabrics. Perhaps the most significant innovation to come from analog testing is the suitport concept, which was extensively tested at HMP. This system integrates the spacesuit with a rover, allowing an astronaut to climb into the suit from inside the vehicle through a rear-entry hatch. This design keeps the dusty suit outside, preventing contamination of the cabin, and allows for much faster and safer transitions to and from an EVA.

Working Outside: EVA Protocols and Emergencies

Extravehicular Activity (EVA), or “spacewalking,” will be one of the most frequent, physically demanding, and highest-risk activities for astronauts on Mars. Future missions will require crews to perform far more EVAs than have been conducted on the International Space Station, often for construction, maintenance, and scientific exploration. Analog missions are therefore essential for developing and practicing safe and efficient EVA protocols, especially for medical emergencies.

Simulations at MDRS and HMP have been instrumental in identifying the immense challenges of responding to an injured crew member during an EVA. Transporting an astronaut who is incapacitated inside a bulky, rigid spacesuit is incredibly difficult. The suit’s life support backpack (PLSS) makes it impossible to lay the person flat on a standard stretcher, and providing any meaningful medical care is out of the question until the crew member is back inside the habitat and the suit is removed. These simulations have driven the development of practical solutions. Researchers have designed and tested modified stretchers with cutouts to accommodate the PLSS, as well as lightweight, collapsible litters (like the Sked and Talon models) that can be easily carried on an EVA. Procedures for two-person carries have been adapted for suited crew members, and all-terrain vehicles have been outfitted with custom stretcher mounts to facilitate transport over rough terrain.

Keeping the Lights On: Habitat Systems and Logistics

The long-term success of a Mars base will depend on the mundane realities of power, water, and supplies. Analog habitats provide an invaluable, unvarnished look at the challenges of keeping these critical systems running in a remote, resource-scarce environment. The daily operational logs from MDRS are a testament to this reality. They are filled with reports of predictable, terrestrial problems: solar power systems that struggle on overcast days, generators that leak oil and consume fuel, water tanks that must be managed to the last drop, and equipment that fails under the strain of continuous use and dust exposure.

What this research reveals is that the greatest operational threats on Mars may not be exotic, unforeseen failures, but rather the accumulation of simple, mundane problems in a context where there is no hardware store, no repair technician, and no resupply ship just around the corner. A leaky water valve or a dead battery is an annoyance on Earth; on Mars, it’s a life-threatening emergency. This understanding directly informs the engineering philosophy for Mars-bound hardware. It prioritizes robustness, simplicity, and repairability over peak performance. A system that is slightly less efficient but can be fixed by an astronaut with a basic toolkit is infinitely more valuable than a high-performance system that requires specialized parts from Earth. This principle extends to the entire supply chain. Detailed logistics studies at HMP, which tracked every item brought to the base, revealed significant inefficiencies in cargo transport and highlighted the need for robust inventory management systems, leading to the testing of technologies like RFID for real-time asset tracking.

The Future: Next-Generation Analogs and Living Off the Land

As our understanding of the challenges of Mars exploration matures, so too do the analog missions designed to solve them. The future of this research is moving toward higher fidelity, longer durations, and a greater emphasis on self-sufficiency. The focus is shifting from simply surviving in a simulated Mars environment to learning how to build a sustainable, long-term human presence there. This involves pioneering new construction techniques, learning to live off the land, and integrating advanced automation and artificial intelligence.

The Next Wave of Habitats

The next generation of analog habitats represents a significant leap in realism. The most prominent example is NASA’s Crew Health and Performance Exploration Analog (CHAPEA). This program involves a series of one-year missions, a duration that surpasses most previous analogs and is designed to gather critical data on the long-term health and performance effects of a Mars mission. What makes CHAPEA particularly forward-looking is its habitat, a 1,700-square-foot structure at Johnson Space Center that was 3D-printed. This approach directly tests the feasibility of using additive manufacturing to construct habitats on planetary surfaces, a technology that could dramatically reduce the mass and cost of future missions.

Alongside these major NASA initiatives, the world of analog missions is becoming more global and specialized. The AMADEE-24 mission, led by the Austrian Space Forum, will take place in Armenia and focus heavily on testing robotic systems and human-robot interaction with communication delays. The Hypatia missions, based at MDRS, are notable for being led by all-female crews from Spain, with a dual focus on conducting scientific research and providing visible role models to inspire young women to pursue careers in science and technology. Educational programs like DES@Mars in Greece are using the analog mission concept to create immersive learning experiences for students, tasking them with building a simulated Martian community. This diversification shows the analog model expanding beyond pure mission prep into education, outreach, and international collaboration.

In-Situ Resource Utilization (ISRU)

Perhaps the most significant paradigm shift in planning for Mars is the concept of In-Situ Resource Utilization (ISRU), or “living off the land”. The cost of launching every kilogram of supplies from Earth to Mars is immense. ISRU aims to make long-term missions feasible and affordable by harvesting and processing local Martian resources to produce vital commodities.

The two primary targets for ISRU on Mars are water ice and the atmosphere. Rovers and orbiters have confirmed the presence of vast quantities of water ice buried in the Martian regolith (soil). This water could be mined and used for drinking, hygiene, growing plants, and, through electrolysis, be split into hydrogen and oxygen. The oxygen could be used for breathable air and as a rocket propellant oxidizer. The Martian atmosphere, which is about 96% carbon dioxide (CO2​), is the other key resource. The Mars Oxygen In-Situ Resource Utilization Experiment (MOXIE), an instrument aboard NASA’s Perseverance rover, has already successfully demonstrated the ability to extract pure oxygen from the Martian atmosphere. This technology is a cornerstone of future plans, as the oxygen could be combined with hydrogen (from water ice) to create methane, a highly efficient rocket fuel for the return journey to Earth.

The ultimate goal of ISRU is construction. Future habitats, landing pads, and radiation shields could be 3D-printed using Martian regolith as the primary building material, mixed with a binding agent or sintered together with high-powered lasers. Analog missions on Earth, particularly in the volcanic terrains of Mauna Kea, are actively testing methods for extracting water and other useful materials from soil that is chemically similar to Martian regolith.

The Rise of Autonomy and AI

The immense communication delay between Earth and Mars makes real-time mission control impossible. Consequently, future crews will need to be far more autonomous, supported by advanced robotics and artificial intelligence (AI) that can serve as an “onboard mission control”. Analog missions are becoming the primary testbed for these intelligent systems.

Robotic assistants are being tested to handle routine maintenance, conduct scientific surveys, and assist with EVAs, freeing up the human crew for more complex tasks. AI-driven software is being developed to help crews schedule their complex daily activities, diagnose system failures, and even provide medical guidance in the absence of an immediate link to doctors on Earth. Virtual Reality (VR) and Augmented Reality (AR) are also playing a growing role. These technologies are used in analog settings to provide highly realistic training simulations for EVAs and emergency procedures, allowing astronauts to practice complex tasks in a virtual Martian environment before ever leaving Earth.

The future of analog research lies at this intersection of human and machine. The goal is no longer just to test a person or a piece of hardware in isolation, but to test the integrated, closed-loop system they form together. It is a shift from practicing survival to rehearsing sustainability, creating a miniature, self-sufficient human-machine ecosystem that can one day be deployed on Mars.

Summary

The long and arduous journey to send humans to Mars begins here on Earth. Through a diverse and evolving portfolio of analog missions, scientists, engineers, and future astronauts are methodically rehearsing every facet of this monumental undertaking. These simulations, conducted in the planet’s most remote and hostile environments, are indispensable for de-risking the exploration of another world.

The history of these missions charts a clear path of growing sophistication. What began as geological expeditions to Mars-like landscapes to understand the planet’s past has transformed into high-fidelity simulations of the entire mission architecture. This evolution reflects a deeper understanding of the challenges, recognizing that the mission’s success depends not only on reliable hardware but on a complex interplay of operations, logistics, and human psychology.

Analog research has provided invaluable, and sometimes harsh, lessons. It has shown that the greatest operational threats may not be novel space-based crises, but the relentless accumulation of mundane maintenance issues—leaky generators, failing batteries, and dust-clogged filters—amplified by a context of extreme isolation and consequence. It has revealed that the human mind is a critical system that must be carefully managed, and that the slow, corrosive pressures of monotony and confinement can be as dangerous as any equipment failure. The data from these missions has driven the development of more robust technologies, more efficient operational procedures, and more effective countermeasures to protect the psychological well-being of the crew.

Looking forward, analog research is focused on the next great challenge: sustainability. The development of In-Situ Resource Utilization (ISRU) technologies to live off the Martian land, the construction of 3D-printed habitats, and the integration of artificial intelligence and robotics are paving the way for a permanent human presence, not just a fleeting visit. These next-generation analogs are testing the systems that will allow future explorers to be self-sufficient, creating a closed-loop, human-machine ecosystem millions of miles from home. The road to Mars is long, but it is being meticulously mapped, tested, and rehearsed, one simulation at a time, right here on our home planet.