NASA’s 1970s Blueprint for a Semi-Permanent Outpost on the Moon

A New Era of Lunar Science

In the afterglow of the final Apollo missions, as the last boot prints faded from public consciousness, a question lingered within the halls of NASA and its industrial partners: What comes next? The race to the Moon had been won, a monumental geopolitical and technological achievement. But for the scientists and engineers who had made it possible, the Moon was not a finish line; it was a starting line. It was a new world, an unopened book of cosmic history, and the brief, fleeting visits of the Apollo astronauts had only revealed the table of contents. To truly read that book, humanity needed more than a temporary campsite; it needed a library, a laboratory, and a permanent address.

In 1971, North American Rockwell, a prime contractor for the Apollo program, delivered a comprehensive answer to that question. The “Lunar Base Synthesis Study” was a multi-volume, exhaustive blueprint for the next logical step in human expansion: a semi-permanent scientific outpost on the Moon, to be established in the 1980s. This was not a vague concept sketch; it was a detailed engineering, operational, and financial plan for a Lunar Surface Base (LSB) designed to support a crew of up to 12 people for missions lasting from two to five years. The study framed the LSB not as a standalone project, but as a key node in a fully integrated space program, working in concert with the planned Earth Orbit Shuttle, a Modular Space Station, and a fleet of reusable interplanetary vehicles.

Direct links to the complete set of 1971 Lunar Base Synthesis Study volumes hosted on NASA’s Technical Reports Server (NTRS):

• Volume 1 — Executive Study (Final Report)
• Volume 2 — Mission Analysis and Lunar Base Synthesis (Final Report)
• Volume 2 — Appendixes (Final Report)
• Volume 3 — Shelter Design (Final Report)
• Volume 3 — Appendixes (Final Report)
• Volume 4 — Cost and Resource Estimates (Final Report)

The vision articulated in these documents represented a fundamental paradigm shift from the Apollo era’s focus on exploration to a new era of scientific occupation. The scale of the ambition was immense. Where Apollo missions lasted for days and carried limited equipment, the LSB was planned for years of continuous operation. The scientific hardware was on a scale previously reserved for terrestrial observatories: a massive 100-inch optical telescope, a drill capable of penetrating 1000 feet into the lunar crust, and a radio telescope array with elements spanning over five miles. This was not a plan for planting flags and collecting rocks; it was a plan to build a permanent scientific institution on another world.

The Four Pillars of Lunar Exploration

The scientific justification for such a monumental undertaking rested on four foundational objectives, each aimed at answering some of the most significant questions about our place in the universe. The base was conceived as a multi-disciplinary research center designed to systematically address these goals.

First was the quest to improve our understanding of the solar system and its origin. The Moon, geologically quiet and lacking the erosive forces of wind and water that have erased Earth’s early history, was seen as a perfectly preserved record of the solar system’s violent birth. By determining its physical and chemical nature, scientists hoped to unlock secrets applicable to all terrestrial planets.

Second, the base would enable comparative planetology. By directly comparing the Earth and the Moon—two bodies formed in the same neighborhood of space but which followed vastly different evolutionary paths—scientists could better understand the unique dynamic processes that shaped our own world, fostered its environment, and ultimately led to the development of life.

Third, the LSB was a platform to evaluate lunar resources and utilize its unique environment. The potential discovery of resources like water ice in permanently shadowed craters could fundamentally change the economics of space travel, providing in-situ propellant and life support consumables. Beyond resources, the Moon itself was a laboratory. Its near-perfect vacuum, extreme stability, low gravity, and the radio-quiet shield of its far side offered an unparalleled environment for research in physics, materials science, and astronomy.

Finally, the base was a crucial step to evaluate and extend human capability in space. By learning to live and work for years in the one-sixth gravity of the Moon, humanity would gain the operational experience and medical knowledge necessary to confidently plan for the exploration of other planetary bodies, most notably Mars.

From Apollo’s Questions to the LSB’s Answers

To achieve these grand objectives, the study laid out a detailed program of research across a wide range of scientific disciplines. Each field had specific questions that could only be answered by a long-term presence.

Geology and Geophysics were at the forefront. The LSB would serve as a base camp for extensive geological mapping and seismic surveys. Scientists planned to investigate the Moon’s deep interior, understand the history of volcanic and impact processes, and explore enigmatic features like the massive Mare Orientale impact basin and the winding, river-like channels known as sinuous rilles, such as the famous Hadley Rille.

For astronomy, the Moon was the ultimate high ground. The study envisioned transforming the lunar surface into the premier astronomical platform in the solar system. The stable surface was ideal for large, sensitive instruments that would be impossible to operate in free-flying orbits. The lack of an atmosphere meant that the entire electromagnetic spectrum, from X-rays to radio waves, would be accessible without distortion. The far side, permanently shielded from the cacophony of Earth’s radio noise, was identified as the most pristine environment in the inner solar system for radio astronomy.

Other disciplines would also flourish. Bioscience experiments would search for evidence of past or present indigenous life deep beneath the surface, while also studying the long-term effects of the lunar environment on terrestrial plants and animals. Aerospace medicine would monitor the crew to understand the physiological and psychological impacts of extended stays in a low-gravity environment. Particles and fields research would use the Moon as a stationary platform to study the solar wind and cosmic rays, unhindered by a planetary magnetic field.

Blueprints for a Lunar Home: Shelter Concepts

The heart of the Lunar Surface Base was the habitat itself—the shelter that would protect the crew, house their laboratories, and serve as the central hub for all operations. The 1971 study presented two distinct but related conceptual designs for this lunar home, both grounded in a philosophy of modularity, safety, and the use of local resources.

The Modular Philosophy

The foundation of the LSB was a modular construction approach. Rather than launching a single, massive habitat, the base would be assembled on-site from a series of standardized, cylindrical modules. The baseline module was designed to be 15 feet in diameter and 30 feet long, a size dictated by the need to transport two at a time within the 60-foot cargo bay of the planned Earth Orbit Shuttle. This modular strategy offered immense advantages: it allowed for a phased, incremental construction timeline, provided inherent redundancy, and gave the base layout a high degree of flexibility to adapt to mission needs or future expansion.

The “Optimized” Baseline Shelter

The first concept was a purpose-built design, optimized from the ground up specifically for the lunar environment and the unique demands of the scientific mission. This “optimized” shelter was envisioned as a complex of eight interconnected modules.

The layout was arranged in a closed-loop or “circular” floor plan. This configuration was a critical safety feature, as it ensured that every module had at least two pathways to the rest of the base, preventing any single module failure from isolating a section of the habitat. The eight-module complex was a self-contained lunar village, comprising:

• Three Crew Modules: Each providing private quarters for four crew members, along with shared facilities like a command center, a medical bay, or a backup galley.
• A Laboratory Module: Housing facilities for geochemistry, sample analysis, and other scientific work.
• A Base Maintenance Module: A workshop for repairing base systems and scientific equipment.
• An Assembly and Recreation Module: Containing the main galley and a common area for dining and relaxation.
• A Drive-in Warehouse: For storing the vast quantities of supplies needed for 180-day resupply cycles.
• A Pressurized Garage: A large, drive-in module for the maintenance and repair of the surface mobility vehicles in a shirtsleeve environment.

Internally, these modules featured an innovative tri-level construction. The central, main level had 8-foot ceilings and was dedicated entirely to living and working spaces. All heavy equipment, tanks, and life support machinery were located in a lower level beneath the floor, while wiring, plumbing, and ductwork ran in an upper level above the ceiling. This design maximized the amount of clear, unobstructed floor space, creating a more open and efficient habitat.

The “Derivative” Shelter (MSS Adaptation)

The second concept explored a more pragmatic, cost-conscious approach: adapting modules from the planned Modular Space Station (MSS) for lunar use. The goal was to leverage the significant investment already planned for the orbital station to reduce the development costs of the lunar base.

This “derivative” shelter would be constructed from a combination of modified MSS modules and two newly designed, specialized modules. The core of the base would be formed by an MSS Core Module, three Crew Modules, two Control Modules, and a Galley Module. the study quickly identified critical deficiencies in the MSS design that made a direct one-for-one use impossible. The orbital modules lacked the large airlocks needed for frequent extra-vehicular activity (EVA) and, most importantly, they had no capability for housing and servicing large surface vehicles. This necessitated the design of two new, specialized LSB modules: a Garage/Airlock and a Warehouse/Airlock, which would be integrated with the adapted MSS components.

Further modifications were required across the board. The meteoroid bumper essential for protection in orbit was unnecessary on the Moon and would be removed. The MSS’s power and thermal systems, designed for the regular sun-shade cycles of Earth orbit, were completely unsuitable for the 14-day lunar night and would need to be replaced with systems designed for the lunar surface.

Shielding with Lunar Soil: Early ISRU

A cornerstone of both shelter designs, and one of the study’s most forward-looking concepts, was the extensive use of local lunar soil, or regolith, for protection. Once the modules were interconnected on the surface, construction vehicles would pile at least six inches of regolith over the entire habitat. This simple yet significantly effective technique, an early form of In-Situ Resource Utilization (ISRU), provided a comprehensive, multi-purpose shield against the three primary hazards of the lunar environment.

First, it offered robust protection from solar radiation. The thick layer of soil would shield the crew from the intense radiation of a major solar flare, a constant threat to any long-duration mission beyond Earth’s magnetic field. Second, it served as a powerful defense against micrometeoroids. The soil would act as a thick, effective bumper, absorbing the energy of constant, high-velocity impacts that could otherwise puncture the habitat’s pressure hull. Finally, it provided crucial thermal insulation. The regolith would buffer the habitat from the extreme temperature swings between the scorching heat of the long lunar day and the cryogenic cold of the lunar night.

The inclusion of a pressurized, drive-in garage and maintenance module in both shelter concepts is a powerful indicator of the study’s long-term vision. Apollo-era hardware, like the Lunar Roving Vehicle, was designed for a single use and then abandoned on the surface. There was no capability for performing complex repairs in a protected, shirtsleeve environment. The LSB plan, by contrast, was built around long-duration science sorties using a fleet of complex, reusable prime movers and trailers. These vehicles would require extensive and regular maintenance—an estimated 168 hours after each major sortie. Performing such intricate work while wearing a cumbersome spacesuit would be extraordinarily inefficient and difficult. The study explicitly analyzed this trade-off and concluded that a pressurized garage was not a luxury but an operational necessity for a sustainable, long-range exploration program. One builds a garage not for a brief visit, but when one intends to stay, to maintain the tools of exploration, and to keep pushing the frontier. It is a symbol of permanence.

The Machinery of a Lunar Colony: Core Technologies and Systems

To sustain a dozen people for years in the most hostile environment ever inhabited, the Lunar Surface Base required a suite of advanced, robust, and highly reliable technologies. The 1971 study detailed the engineering heart of the base, outlining the core systems for power, life support, mobility, and communications that would transform a collection of inert modules into a functioning outpost.

Powering the Base: The Nuclear Choice

The single greatest technological challenge for any permanent lunar settlement is surviving the 14-day lunar night. This long period of darkness renders solar power impractical without an astonishingly massive energy storage system. The study calculated that a solar array system with enough batteries to last through the lunar night would require over 5,600 square feet of solar panels and more than 300,000 pounds of batteries—a mass far too great to be logistically feasible.

The clear solution was nuclear power. The selected concept was a mobile, modular radioisotope power system. Each power unit would use the steady heat from the radioactive decay of Plutonium-238 to drive two redundant organic Rankine cycle converters, generating a continuous 3.5 kilowatts of electricity (kWe). The entire system—heat source, converters, and radiators—was designed to be mounted on a wheeled trailer, creating a “power cart.” This modular approach provided incredible flexibility. Several power carts could be linked together at the main base to meet its total energy demand, while a single cart could be detached to travel with the four-person crew on their long-duration scientific sorties, providing life support and instrument power hundreds of miles from home.

A Breathable, Drinkable World: Closed-Loop Life Support

With resupply missions from Earth occurring only once every 180 days, recycling essential consumables like air and water was not an option but an absolute necessity. The LSB was designed with a nearly self-sufficient, closed-loop life support system, a miniature Earth-like ecosystem sealed within the habitat’s walls.

The air revitalization system would continuously scrub the carbon dioxide (CO2​) exhaled by the crew. This captured CO2​ would then be fed into a Sabatier reactor, where it would react with hydrogen to produce water and methane. The methane would be vented, while the newly created water would be sent to an electrolysis unit. This unit would use electricity from the nuclear power source to split the water back into breathable oxygen, which was returned to the cabin atmosphere, and hydrogen, which was recycled back to the Sabatier reactor to continue the process.

Water reclamation was equally critical. All wastewater, from every source—showers, sinks, humidity condensate from the air, and even urine—was to be collected and purified. The study recommended a sophisticated dual-loop system. A reverse osmosis system would handle “grey water” from washing, purifying it for reuse in hygiene and cleaning. A more thorough vapor compression distillation process would purify all other wastewater, including the brine from the reverse osmosis unit, to produce sterile, potable water fit for drinking and food preparation.

Exploring the Frontier: The ‘Overland Train’ Mobility Concept

To enable the ambitious scientific goal of 90-day remote exploration sorties, the LSB required a mobility system far more capable than the simple Apollo rover. The study envisioned a robust, multi-vehicle system conceived as an “overland train.”

The lead vehicle was the Prime Mover, a large, six-wheeled vehicle with an articulating frame for traversing rough terrain. Crucially, it featured a fully pressurized cab, allowing two crew members to operate it in a shirtsleeve environment for extended periods, saving precious time and resources that would otherwise be spent on EVA. For long sorties, the Prime Mover would tow a series of powered trailers:

• A Mobile Shelter Module, an 8-foot by 22-foot pressurized cylinder that served as the crew’s living quarters, laboratory, and refuge during the long traverse.
• A Mobile Power Unit, the 3.5 kWe radioisotope power system on its dedicated trailer, providing all the energy for the sortie train.
• Utility and Cargo Trailers, carrying the scientific equipment, drilling rigs, tools, and supplies needed for the 90-day mission.

This overland train was a self-sufficient outpost on wheels, capable of supporting a four-person science team for months at a time as they explored regions hundreds of miles from the main base.

Connecting to Earth: Communications Architecture

Maintaining a constant link with Earth for voice, video, and the immense flow of scientific data was a vital function of the base. For a base located on the Moon’s near side, this was a relatively straightforward challenge. A large S-band parabolic antenna at the LSB would maintain a direct, continuous line-of-sight connection with the Manned Space Flight Network on Earth.

The most desirable location for radio astronomy was the lunar far side, permanently shielded from Earth’s radio interference. A far-side base would have no direct line of sight to Earth, posing a major communications problem. The study proposed an elegant and forward-thinking solution: a dedicated communications relay satellite. This satellite would not orbit the Moon, but would instead be placed in a special “halo orbit” around the Earth-Moon L2 Lagrange point—a gravitationally stable point in space located about 40,000 miles beyond the Moon. From this unique vantage point, the satellite would have a continuous, simultaneous line of sight to both the lunar far side and the Earth, serving as a permanent, over-the-horizon communications bridge.

The design of these core technologies reveals a deeply interconnected systems-engineering approach. The most ambitious scientific goal—the 90-day, four-man remote sortie—served as the central design driver for nearly every major system on the base. The logic flowed directly from the science. To explore distant regions for months at a time required a mobile, pressurized shelter. This mobile shelter, operating far from the main base and through the long lunar night, required a continuous, high-output power source, which could only be a mobile nuclear system. The logistical impossibility of carrying 90 days’ worth of air and water for four people mandated the development of a lightweight, efficient, closed-loop life support system that could operate on the sortie train. Thus, the scientific ambition directly shaped the engineering reality, creating an interlocking suite of technologies where the mobility, power, and life support systems were not independent, but were a single, integrated system designed for one primary purpose: long-range surface exploration.

Life and Work on a New World: The Human Element

Beyond the advanced hardware and complex systems, the Lunar Surface Base was ultimately a human endeavor. The 1971 study dedicated significant analysis to the crew who would inhabit this new world, defining their roles, their work, their daily lives, and the scientific missions they would undertake.

The Lunar Crew

The permanent crew of the LSB was planned to be 12 specialists. To ensure continuity and a constant transfer of operational knowledge, crew rotations were planned to be staggered, with half the crew returning to Earth every 180 days. This meant that new arrivals would always be integrated into an experienced team, a critical factor for safety and efficiency. The proposed tour of duty was remarkably long, up to one full year on the lunar surface.

The composition of the crew reflected the nature of the base as a self-sufficient, multi-disciplinary research outpost. The roster went far beyond the pilots and geologists of the Apollo era. It included a Base Commander, electronics and mechanical engineers, specialized technicians, a medical expert (a highly trained paramedic or “Medex” rather than a full M.D.), optical and radio astronomers, geochemists, geophysicists, and even a civil engineer to oversee construction and maintenance.

A Day on the Moon

Life on the Moon was envisioned as rigorous and work-oriented. The standard schedule was a 10-hour workday, six days a week. The 24-hour cycle was carefully budgeted to include eight hours for sleep, two and a half hours for meals, and another two and a half hours for recreation, exercise, and medical check-ups. For crew members performing tasks outside the habitat in spacesuits (EVA), the 10-hour shift included 6.5 hours of productive work time, with the remaining 3.5 hours allocated for the lengthy processes of suiting up, pre- and post-EVA checks, and debriefing.

The Primary Scientific Missions

The crew’s work was centered around three major scientific campaigns, each a massive undertaking in its own right.

Remote Exploration Sorties were the flagship activity of the LSB. A four-person team would embark on long-duration traverses in the “overland train” mobility system. These missions could last up to 90 days, covering hundreds of miles as the crew conducted detailed geological mapping, deployed geophysical instruments for seismic profiling, and used shallow drills to collect core samples from scientifically interesting sites.

Observatory Operations represented a monumental construction and scientific project. The crew would be responsible for the on-site assembly of the massive 100-inch optical telescope, a task involving the painstaking alignment of its large mirrors and the construction of its support structures. They would also deploy the vast antenna arrays for the radio telescopes, some of which stretched for miles across the lunar landscape.

Deep Drilling was another major mission. A two-man team would operate a powerful drill rig designed to penetrate 1000 feet into the lunar crust to retrieve pristine samples of deep lunar material. This was a slow and demanding process, estimated to take over 100 days to complete a single hole. The study strongly recommended that this task be performed from within a dedicated, pressurized module. This would not only protect the crew and equipment from the harsh lunar environment but would also dramatically increase efficiency, cutting the time required for the mission nearly in half compared to performing the same work in cumbersome spacesuits.

A Home on the Moon

The habitat was designed to be more than just a sterile laboratory; it was a home, engineered for long-term comfort and psychological well-being. Each of the 12 crew members was provided with a small, private stateroom containing a bunk, a desk, and storage space—a crucial provision for personal time and privacy during a year-long mission.

Communal areas were designed to foster social interaction and morale. A primary galley was equipped to prepare a variety of frozen and rehydratable foods. The adjacent dining and recreation area served as the social hub of the base, a place for shared meals, games, and entertainment. Medical care was provided in a dedicated facility staffed by the Medex, equipped for everything from routine check-ups to stabilizing a crew member for an emergency return to Earth.

The planning documents reveal a sophisticated awareness of the human factors inherent in long-duration, isolated missions. The strict adherence to a two-person “buddy system” for all activities outside the habitat was a fundamental safety protocol. The decision to rotate only half the crew at a time was equally critical, ensuring that hard-won, site-specific operational knowledge was never completely lost. This overlapping of crews provided a continuous on-the-job training environment, where veteran members could mentor new arrivals, dramatically improving both safety and efficiency. This concept of institutional knowledge transfer, combined with provisions for private communication with family on Earth, demonstrates a deep understanding that the success of a permanent outpost would depend as much on managing human psychology as it would on engineering reliable hardware.

The Earth-Moon Bridge: Logistics and Construction

The Lunar Surface Base, for all its advanced technology, could not exist in isolation. It was the final destination at the end of a long and complex logistical chain stretching back to Earth. The 1971 study detailed the intricate choreography of transporting the base’s components across a quarter-million miles of space and assembling them on the lunar surface, a plan that relied entirely on the ambitious, reusable space transportation infrastructure envisioned for the 1980s.

The Transportation System

The entire LSB concept was predicated on the existence of a three-stage, fully reusable space transportation system.

The first stage was the Earth Orbit Shuttle (EOS), the workhorse vehicle that would lift the base modules, cargo, and propellants from the launch pad at Kennedy Space Center to a staging point in low Earth orbit.

The second stage was the Cislunar Shuttle, a powerful interplanetary vehicle responsible for the long, multi-day journey from Earth orbit to lunar orbit. The study considered two options for this vehicle: a Reusable Nuclear Shuttle (RNS) powered by a nuclear thermal rocket, or a large Chemical Interorbital Shuttle (CIS).

The final and most critical link was the Reusable Space Tug. This versatile lander would descend from lunar orbit to the lunar surface, delivering the habitat modules and cargo. After its payload was unloaded, it would ascend back to lunar orbit to be refueled and reused for subsequent missions, or to return crew and scientific samples to the waiting Cislunar Shuttle. To maximize its payload capacity for the heavy descent phase, the study proposed a “Stage-And-A-Half” concept for the Tug. It would use a large, expendable propellant tank for most of its descent, jettisoning the empty tank on the lunar surface before completing its landing and subsequent ascent using its smaller, internal propellant load.

The Buildup Sequence: A Step-by-Step Assembly

The construction of the base was planned as a carefully sequenced series of five landings over approximately five months, a mix of unmanned cargo deliveries and manned crew arrivals.

The process would begin with an unmanned landing (Flight 1U). The first Space Tug would autonomously touch down at a pre-selected site, delivering the initial core modules of the habitat—the Garage, Crew/Medical, Crew/Operations, and Assembly/Recreation modules—along with the first mobile power cart and essential construction equipment.

About a month later, the first crew would arrive (Flight 1M). This four-person buildup team would bring with them the first Prime Mover vehicle, another power cart, the Warehouse module, and the deep drilling rig. Their primary task would be to begin the arduous process of unloading, connecting, and activating the initial modules to establish a livable foothold on the Moon.

A series of alternating unmanned and manned flights would follow in rapid succession. Flight 2U would deliver more power carts and observatory equipment. Flight 2M would bring six more crew members and the 50-inch telescope. The final buildup flight, 3U, would deliver the last two crew members and the remaining base hardware. By the end of this five-month period, the full 12-person crew would be on-site, and the base would be fully assembled and ready to begin its multi-year scientific mission.

Construction on the Moon

Once the modules and equipment were on the surface, the real construction work would begin. The key piece of equipment for this phase was the Prime Mover, equipped with a versatile hoist attachment. The crew would use the Prime Mover to carefully lift each 10,000-pound habitat module off the Space Tug lander, transport it to the prepared base site, and meticulously position it for interconnection with the other modules.

The final major construction task was to provide the base with its protective shield. The Prime Mover, now fitted with a dozer blade or skiploader bucket, would be used to move tons of lunar soil, piling it over and around the assembled habitat until it was covered by a layer at least six inches thick.

This entire logistics and construction plan treats the lunar base not as a traditional, monolithic spacecraft launched in one piece, but as a complex “kit of parts” to be assembled on-site. The emphasis on modularity, specialized ground support equipment like the Prime Mover, and on-site civil engineering tasks like grading and burying the habitat, mirrors the process of building a remote terrestrial research station more than it does a typical space mission. It reveals a vision of lunar development that is fundamentally about construction and long-term settlement, not just a brief visit.

The Bottom Line: A Vision’s Price Tag

A vision of this magnitude required a clear-eyed assessment of its cost. The final volume of the 1971 study presented a detailed financial analysis, breaking down the projected expenses for the entire Lunar Surface Base program. This analysis provided not just a total price tag, but also a crucial comparison of the two competing shelter concepts, revealing the economic trade-offs at the heart of the project.

Total Program Cost

The study estimated the total cost for the Lunar Surface Base Project—including the shelter, all scientific equipment, the mobility systems, and the power sources—to be approximately $2.5 billion in 1971 dollars. It’s important to note that this figure did not include the substantial development costs for the necessary transportation infrastructure, such as the Earth Orbit Shuttle and the Cislunar Shuttle, which were considered part of a separate, overarching space program budget.

The total cost was remarkably similar for both shelter concepts:

• Optimized Baseline Concept: $2,545.7 million
• MSS Derivative Concept: $2,530.9 million

Cost Breakdown by Major Element

The total program cost was distributed across four main projects. The costs for the scientific equipment, mobility systems, and power sources were common to both shelter concepts, as these elements were required regardless of the habitat’s design.

• LSB Shelter Project: This was the largest single component, covering the design, development, and production of the habitat modules and all associated support. It was estimated at approximately $861 million to $876 million.
• Science Equipment Project: This covered the development of all scientific instruments, from the massive 100-inch telescope to the deep drill and the full suite of geological and geophysical sensors. Its cost was estimated at $833 million.
• Mobility Equipment Project: This included the development of the Prime Movers, the mobile shelter, and all the specialized trailers for the “overland train.” The estimated cost was $645.5 million.
• Electrical Power Source Project: This covered the development of the mobile radioisotope power systems and was estimated at $191.2 million.

The Central Trade-Off: Optimized vs. Derivative Shelter

The core economic question posed by the study was whether it was cheaper to design a purpose-built lunar shelter from the ground up or to save money by adapting a design from the planned Modular Space Station. The results of the cost analysis were striking and somewhat counterintuitive.

The MSS Derivative concept offered a net savings of only $15.1 million over the Optimized Baseline—a difference of less than 2% of the total shelter project cost. This marginal advantage was the result of a complex trade-off between upfront development costs and long-term production costs.

The derivative shelter was significantly cheaper in the non-recurring phase, which includes Design, Development, Test, and Evaluation (DDT&E). Here, it saved about $66 million by leveraging existing MSS designs. this advantage was almost entirely erased by higher recurring, or production, costs. The derivative shelter was about $33 million more expensive to build because it ultimately required an extra module to meet all mission requirements, and its adapted subsystems were generally heavier and more complex than their optimized counterparts.

The following table provides a detailed breakdown of this critical cost comparison, illustrating how the initial development savings of the derivative concept were offset by higher costs in production and support.

The most significant conclusion from this detailed cost analysis was not simply that the two concepts were similarly priced. Instead, it revealed the triumph of the overarching “integrated space program” philosophy. The reason the cost difference was so small was that the “optimized” baseline design was not created in a vacuum. It was intelligently optimized for the lunar mission while already maximizing the use of common subsystems, technologies, and manufacturing processes being developed for the space station program. The real economic advantage, the study showed, came from planning multiple major space programs in concert to achieve deep technological synergy, rather than trying to retrofit one program’s hardware for another’s purpose after the fact.

Summary

The 1971 Lunar Base Synthesis Study stands as a remarkable document, a testament to the long-range vision and detailed engineering prowess of the early space age. It provided a comprehensive, technically sound, and extraordinarily forward-looking blueprint for a sustained human presence on the Moon. This was not a work of science fiction, but a meticulous engineering and operational plan that addressed every facet of establishing and operating a scientific outpost on another world.

The study moved beyond the geopolitical motivations of Apollo to lay out a compelling scientific case for lunar occupation, centered on fundamental questions of planetary science, astronomy, and the potential for resource utilization. It detailed two viable habitat concepts—one optimized for the Moon, the other adapted from an orbital space station—and concluded that both were feasible, with the optimized design offering greater efficiency for only a marginal increase in cost.

The technological solutions proposed were both robust and innovative. The selection of a mobile, modular nuclear power system correctly identified the immense challenge of the 14-day lunar night. The design of a closed-loop life support system acknowledged the logistical imperative of recycling in a remote environment. The “overland train” mobility concept provided a credible means for conducting long-range, long-duration exploration. The plan for an on-site, multi-stage construction process, culminating in the use of lunar soil for shielding, demonstrated a practical, engineering-based approach to building on another world.

The study’s most significant contribution was its integrated vision. It understood that a lunar base could not be designed in isolation. Its success was intrinsically linked to a larger ecosystem of reusable transportation, including an Earth Orbit Shuttle and an interplanetary Cislunar Shuttle and Tug. It recognized that the greatest efficiencies were to be found not in simply reusing hardware, but in designing entire programs—Shuttle, Station, and Base—to be technologically synergistic from the outset.

In the decades that followed, the political will and financial commitment required to realize such a grand vision faded. The integrated space program was never fully built, and the blueprints for the Lunar Surface Base were archived. Yet, the fundamental logic, the scientific ambitions, and the core engineering solutions detailed in this 1971 study remain significantly relevant. As humanity once again sets its sights on returning to the Moon, these documents serve as more than just a historical curiosity. They are a detailed roadmap, drawn a half-century ago, that still points the way toward a permanent human future on the lunar frontier.