Introduction

A planetary base is sort of like a space station on the surface of a planet or moon. The base has a focus on supporting some particular endeavour, such as a Mars Exploration mission, a military base, a planetary defense fortress, a military observation post, a military picket along the neutral zone, a trading post or "factory", a mining operation, the interstellar equivalent of a lighthouse hazard beacon, or something along those lines.

For whatever reason it makes more sense to locate the facillity on the surface of a planet instead of a space station.

The presence of a base may encourage other bases to be established in the same location (see Boomtown). This can grow to the point where the establishment becomes a full fledged colony. This can occur with both a military outpost and with a civilian commercial trading post.

The main difference between a base and a colony is that the members of a colony do not expect to ever leave.

A new base is established with rugged cargo spacecraft that can handle landing in a wilderness or otherwise undeveloped area. If the base is planned to be expanded, adding a spaceport will be a big help (even if it is just an area that has been bulldozed flat). Trading posts will put up warehouses, even if it is just a shack to hold the local product responsible for the the existence of a post on such a forlorn planet. Warehouses are also useful to store the glass beads, iron kettles, or whatever cheap junk that the ignorant natives think is valuable enough to trade for in exchange for the beforementioned valuable local product.

Like any other living system, the internal operations of a planetary base can be analyzed with Living Systems Theory, to discover sources of interesting plot complications.

Base Functions

Agriculture
Food-producing station
Exploration
A base to support the exploration of the planet. Commonly encountered as a lunar exploration base or Mars exploration base.
Fuel Depot
Fuel refining and storage facility
Industrial
Factory or smelting plant. To be located near required raw materials, and far from colonies who object to air/water/land pollution.
Mining
Base supporting mining operations, perhaps with an ore refinery.
Pirate Haven
Space pirates need infrastructure (fences for pirated loot, fuel and reaction mass, ship repairs, R&R for the crew). A hidden planetary base can act as a Pirate Haven and cater to these needs.
Planetary Defense
Armed military station defending its planet from outside attack, planetary fortress.
Repair Depot
Emergency cache of critical spacecraft repair tools and replacement parts. Probably under lock and key to restrict access to authorized spacecraft.
Research
Scientific research. The base either studies the planet in general or some interesting local phenomenon. Alternatively it can be for researching dangerous technologies, where the planet can be considered expendable. Though in that case it would make more sense to put the base on a space station.
Staging
Forward base to support spacecraft. May be civilian or military. Generally located in a "remote" location, remote being defined as "a long distance from the home base of the supported spacecraft." (e.g., a military base can be "remote" even if it is near a huge metropolitan planet belonging to a hostile nation).
Tax Haven / Data Haven
These are tax shelters used by the wealthy and by corporations. They are located near the planet a corporation is based on, but are outside territorial limits. More details here.
Transport Nexus
A Transport Nexus is a crossroad spaceport for passengers, a port of entry, warehouses where valuable minerals from asteroid mines are stored and trade goods transshipped, or a "trade-town".
Trading Post
"Trading Post" or "Factory" set up by a merchant to trade their imported goods with the natives in exchange for the native's valuable local goods. The base is run by the merchant, or by a "factor" who is employed by the merchant (which is where the name "factory" comes from). The preferred route between trading posts is called the "trade route", though that does not translate well into orbital trajectories. Trade routes might make sense with certain types of faster-than-light starships.

Sample Asteroid Base

This is based on a 1981 Boeing report Controlled Ecological Life Support System: Transportation Analysis.

For details about the fusion powered transport ship, go here.

4.5 Asteroid Base

The mission assumes an asteroid mining operation with a 5000 person habitat. The complex transportation scenario for this advanced mission involves four different vehicles and three separate space bases (refs. 86 and 91).


c. The GEO base serves as the final assembly area for the large fusion rocket system used to propel payloads out to the asteroids. Cargo and propellant are unloaded from electric-powered transfer vehicles sent up from the LEO base. The enlarged OTV used to transfer personnel and priority cargo is designed to transport 441,000 lb (200,000 kg) from LEO to GEO. The complex fusion propulsion system is assembled at the base with the fusion power core, propellant tanks, large thermal radiators, and the personnnel and priority cargo modules. The resulting vehicle, shown in figure 4-11, can transport 1250 passengers and 150 metric tons of priority cargo to the asteroids.

The gross start mass for the resupply mission would be 10,000 metric tons, of which power plant comprises 2000 tons; hydrogen propellant, 4000 tons; and payload, 4000 tons (1250-person habitat plus consumables and priority cargo). The power plant consists of two 6 GW fusion reactors utilizing the deuterium-deuterium fusion reaction. The total power plan provides 4.8 GW of thrust power while radiating almost 2.8 GW of waste heat and 4.4 GW of high energy neutrons.

d. There are two methods the fusion rocket will use to propel vehicles to the asteroid base: fast transfer for personnel and priority cargo, and slow transfer for nonpriority cargo. The manned resupply mission is a fast hyperbolic transfer orbit consisting of an 11-day thrust period to achieve hyperbolic velocity, followed by a 226-day coasting, and a 13-day deceleration to match velocity with the asteroid base. The return mission leaves the asteroid approximately 113 days later for a reverse of the ascent mission.

The second method is used to accelerate unmanned cargo pods on a slow elliptical (Hohmann) transfer orbit out to the asteroid base. Figure 4-12 illustrates the different trajectories. The slower trip takes 130 days longer but costs less than half of what the fast, hyperbolic trip costs. All nonpriority cargo is brought to the asteroid facility in this manner. Empty cargo pods are not returned to Earth, they may be discarded or used in a variety of ways as storage modules or Closed Ecological Life Support System (CELSS) modules.

e. A fleet of two fusion rockets is envisioned. They each make one round trip per asteroid orbit (synodic cycle) to the asteroid mining facility and leave a few days apart. Because of the synodic cycle, the fusion rocket vehicles are delayed at the asteroid base for approximately 113 days, at the GEO location they are delayed approximately 288 days. During these delays the fusion rockets are used to decelerate unmanned cargo pods at the asteroid base and to accelerate the pods at GEO. Cargo pod launches are timed to arrive at the asteroid base shortly after the manned resupply vehicles so that the fusion rockets can decelerate the cargo pods. The rendezvous opportunity (synodic cycle) repeats itself every 928 days. This transportation system allows half of the total crew to be rotated each cycle.


86. Advanced Propulsion Systems Concept for Orbital Transfer. 1981. NAS8-33935.

91. Technology Requirements for Future Earth-to-Geosynchronous Orbit Transportation Systems. June 1980. NAS1-15301.

William Black:

This is still a work in progress, and more or less I’m attempting Winchell’s stone soup method. I’ve previously come up with a model for an asteroid mining base, I haven’t plugged in numbers for every item yet, I’m looking up references and doing research, this is what I have so far. This is all preliminary, so feel free to make suggestions.

In this case the report suggests these 1,250 persons are passengers en route an asteroid mining base.

With extensive automation (at the base) crew size would be determined by maintenance and servicing needs. Total crew size depends on the scale of the operation. In my experience many people suffer from a lack of perspective when it comes to industrial scale commercial operations. It’s very easy to think; “well this will all be automated, so there hardly need be any personnel.” Well, the equipment has to run 24/7 and when its down the operation is not making money. So even if your mining equipment is largely automated or robotic, it has to be monitored, maintained, and repaired in the field, or even recovered and brought into the shop situated at the main base for repair.

I’ve prepared a rough breakdown based partly on my own work for my own future history setting but adapted to this scenario.

The report specifies an asteroid mining base, specifically a commercial operation, with a base population of 5000. The report is not specific on what is being mined, but the example given is Ceres. We might speculate this is an ice mining operation recovering water ice to feed electrolysis plants separating hydrogen and oxygen on an industrial scale, perhaps in support of other large scale mining operations spread across the asteroid belt. Perhaps providing material for transit to propellant depots located elsewhere. There are similar operations in my future history setting and I’ve done some research on this previously.

Fusion powered Transport

The fusion powered transport might need as few as 3 to 4 flight crew I would think. Pilot, co pilot, navigation/communications officer, power-systems specialist. 4 crew per watch, 4 watches per 24 hours in-flight. So a flight crew of 16.

In regards the asteroid mining base:

Assume commercial operations running four shifts 24/7.

Operations management follows a mission control model managing one hundred remote mining sites scattered over a relatively large area, each with autonomous robotic mining/excavating vehicles and/or drilling rigs. Autonomous loaders, conveyors, for feeding material into separators for processing. Autonomous vehicles to remove and cart away waste material for disposal. Electrolysis plants for separating water ice to hydrogen/oxygen and a ice-melt and filtration plant producing fresh water for base consumption.

Mission Control

Mission control is situated at the main base. Operators remotely monitor operations at each site and assign a trouble shooting tickets for breakdowns and malfunctions.

Each mission control operator handles two remote operations sites, so mission control needs 50 men per shift x 4 shifts: 200 mission control operators.

Trouble shooting maintenance/repair teams for each operational site:

Software/hardware computer team

2 technicians each shift for each site. 200 technicians per shift x 4 shifts: 800 technicians.

Responsible for remote autonomous vehicles primary control systems including sensors and switches, data uplinks, and other operational mining site-to-mission control communications systems, remote cameras and the like.

Mechanical team 1

Stationed at central maintenance hub.

Eight crew for each operational site, per shift, x 4 shifts. 3200 crew

Responsible for

Hardware: remote manipulator systems
Hardware: conveyor systems
Hardware: motors/drive systems
Hardware: pneumatics/hydraulics
Hardware: thermal management, heaters and heat rejection systems
Hardware: electronics

Mechanical team 2, Surface EVA

Four recovery/maintenance teams for each shift, with a five man crew for each. 20 men per shift x 4 shifts: 80 man surface recovery/on-site maintenance crew.

Manages remote autonomous vehicle recovery and/or maintenance in-field and transportation of units back to central maintenance hub.

Cryogenics team.

Manages handling, storage, and transfer of cryogenic materials.
Maintains refueling station for cargo and personnel surface to orbit transfer vehicles and surface-to-surface suborbital transports.
Manages maintenance and repair of cryogenic systems.

Base Hospital

Staff 200
Emergency trauma team on duty 24/7.
Surgical suite staffed 24/7
General care services staffed daily, say 9-5.
Hospital/recovery services, nursing staff, on duty 24/7.

EMT EVA Team

Two five man teams per shift x 4 shifts: 40 crew.

This might just be a meat wagon. A suit failure on the surface of Ceres say fifty kilometers from the base, or a vehicle crash wouldn’t be likely to leave survivors, but it is possible crew may survive such incidents and require rescue.

Base Stores

Warehouse/supplies management & cargo/freight handling crew, warehousing would likely be largely automated such as large scale commercial systems commonly used in the air freight industry today, still a certain number of human operators are required and inventory control needs a certain level of human intervention.

Base Police Force

Staff on duty 24/7.

I took a look at personnel per population studies and most specify 1.8 to 2.3 police officers per 1,000 residents. So, ten officers per shift x 4 shifts: 40 officers. Call center/dispatch staff of 2 per shift x 4 shifts: 8 dispatch staff.

Base Systems

Life support systems, plumbing, air circulation, electrical, computer network, power systems management crew, staff on duty 24/7. 50 man crew on duty each shift x 4 shifts: 200 man crew.

Base Command

Watch officers, office staff, manages book keeping and accounting, documentation of all issues, and maintains base database and records. Watch officer staff on duty 24/7.

Communications Center staff

?

Flight Team

48 dedicated pilots

Flight Operations Control Center

For my theoretical commercial operation I’ve assumed all propulsive vehicles rather than surface crawlers.

Pilots control all suborbital point-to-point vehicles, equipment retrieval vehicles, cargo tugs, EMT EVA transports. Base flight crew is supplemented by crew from fusion transport flight crew who are stationed on the base for 113 days between arrival and departure. The fusion powered transport is used to decelerate unmanned cargo pod shots between arrival and departure. Since the fusion drive system cannot be fired in close proximity to the base there need be a number of cargo tugs to load and off-load cargo pods and transfer personnel between base and the fusion powered transport.

Number of and types of vehicles:

Equipment recovery and on-site maintenance vehicles: 4
EMT EVA Rescue vehicles: 2
Cargo Tugs: 4
Fleet Size: 10 vehicles.

These might be differently equipped vehicles of a single common type. For example the Equipment recovery and on-site maintenance vehicle might carry a tool crib and spare parts storage bay with an on-board work station where the EMT EVA Rescue vehicle would carry a medical pod with an on-board trauma suite. Personnel transfer craft might be cargo tugs with a passenger module rather than a cargo pod.

Flight Center Vehicle Maintenance Crew

100 vehicle specialists, 25 on duty per shift.

Additional Base Personnel

Cafeteria
Food Preparation & service staff

With a base of this scale there are likely to be attached concessions, a convenience store, fast food outlets, or even an upscale restaurant or two, a bar/night club, a theater perhaps. Likely the base has its own on-site local internet, television and movie channels playing recorded material.


In my model I’ve assigned duty stations/shifts to 4,676 Base personnel leaving 324 base personnel split among the various positions with uncounted crew.

Comment by William Black in a thread on Google Plus (2015)

Sample Lunar Base

2.4.6.1 Elements and Systems Description

Figure 2.4.6-1 summarizes the surface elements identified to support Case Study 4. In addition to those identified in the previous case studies (EMU's, Phobos EVA systems, construction equipment, regolith baggers, unpressurized rovers), the list includes many new elements. The surface habitats involve three major life-enabling components: structure, environmental control and life support system (ECLSS), and thermal control system (TCS). The ECLSS is substantially closed to reduce the logistics strain of continuous occupation. A pressurized rover permits extended traverses. Plants use local resources to produce substantial amounts of rocket propellants. Increased power needs are provided by a megawatt-class nuclear power plant.

Figure 2.4.6-2 depicts a concept for the lunar base layout. Primary power is provided by a nuclear plant whose reactor core is shielded by burying it in regolith allowing some freedom to place it near habitat and laboratory areas. Oxygen plants are located some distance away for safety and to isolate dust and contaminants. The liquid oxygen product is stored in buried tanks to facilitate cooling. A permanent landing/launch pad area lies some kilometers from the base to isolate debris lofted by rocket exhaust. Various navigation aids lie along the lander flight path. Support equipment provides services such as refueling and auxiliary power to landers while at the base. Improved roadways ease access between the major areas.

Inflatable/erectable habitat structures are chosen over modules since they provide more volume for a given mass. The inflatable, depicted in figure 2.4.6-3, consists of a spherical pneumatic envelope around a structural cage that supports floors, walls, and equipment. The cage also supports the envelope if pressure is lost. The design assumes that the habitat is inflated to standard sea-level pressure. A 2-m diameter vertical shaft provides access for crew and equipment. The habitat includes two airlocks, one of which is provided by a construction shack module that is connected to the inflatable by a flexible tunnel. The airlocks have front porches to facilitate cleaning and dusting off extravehicular mobility units (EMU's). The lower half of the habitat is buried below the surface and the top half is covered with bagged regolith for shielding from radiation and micrometeoroids. Burying substantially reduces hazards from external radiation. The envelope is a high-strength multi-ply fabric with an impermeable inner layer and a thermal coating outside. The structural frame is a cage of longitudinal and latitudinal curved beams that surround a combination of radial and concentric beams that support the flooring. A 16-m-diameter configuration has four floors and can house 12 crewmembers with total floorspace of 594 m2. If made of a material similar to Kevlar-29, the envelope would be about 5 mm thick and would weigh about 3.3 t. The remaining mass totals about 16.3t and includes the structural frame (9 t), floor (6 t) and walls (1.3t).

Inflatables require more time to set up than pre-outfitted modules. In the current concept, a construction shack module lands near a hole that has been excavated with explosives. After shaping the hole, the inflatable is laid out, anchored, and erected. Covering with regolith is the most time-consuming task and is a prime candidate for automation.

A regenerative ECLSS is necessary for extended-duration missions to avoid prohibitive resupply logistics. The initial lunar ECLSS uses physical and chemical methods to regenerate oxygen and obtain 97 percent closure of the water cycle. ECLSS technology is assumed to evolve so that the Mars ECLSS is bioregenerative with partial closure of the food loop. The martian system uses local resources to make up water, oxygen, and nitrogen losses.

Total ECLSS closure is not feasible. Even the most optimistic estimates for a lunar base envision a bioregenerative system that recycles about 97 percent of the total mass with resupply of gasses lost through leaks and airlocks. The most important material loops are water, gasses, and food. Water is especially important because of its weight: resupply needs are about 0.93 t/yr per person with 90 percent closure and 0.28 t/yr per person with 97 percent closure. To achieve 97 percent closure involves recycling humidity condensates, wash and hygiene water, and urine. A major trade in designing an ECLSS is the cost of closure versus resupply. It is generally more economical to resupply trace substances than to recycle or reproduce them. With this in mind, the basic goals of regenerative ECLSS can be summarized as follows:

a. Keep material losses to a minimum.
b. Recover useful material from waste.
c. Reduce resupply logistics to a minimum.

The first two goals can be accomplished with physical and chemical means. Achieving the third goal requires post-Space Station Freedom ECLSS and/or biological systems.

The TCS provides for passive protection, acquisition, transport, and rejection of latent and sensible heat. Inside the habitat the major heat sources are metabolism and equipment. Since regolith provides good insulation from the surface environment, the major problem is heat rejection. To handle the drastic temperature variations in a lunar day, a cascaded vapor cycle system is envisioned. Two loops provide adequate heat rejection during the day when temperatures can reach 130°C and a bypass is provided to prevent over rejection at night when temperatures can fall below -150°C The system provides final rejection temperatures of 43°C and 67°C to reject both the metabolic and equipment heat-loads during the day and provides a final rejection temperature of-11 °C to reject the heat loads during the lunar night.

Radiation protection is a major concern for long-term habitation of extraterrestrial surfaces. The major hazards are from solar flares and lengthened exposure to galactic cosmic radiation (GCR). Solar flares occur sporadically and are roughly correlated with the sunspot cycle. GCR contains many more energetic particles man solar flares but at substantially lower fluxes. Solar flares can be lethal over short time periods whereas GCR presents a more long-term hazard. Shields of bagged regolith about 50-100 cm thick have been estimated to achieve a tolerable radiation environment for solar events. The shields also suffice for protection from micrometeoroids which generally penetrate only a few centimeters. Current GCR models are not yet adequate for predicting long-term shielding needs. With such coverings the habitats provide an adequate haven during a solar storm. EVA crew are at risk unless they can retreat to the habitat or some temporary haven. A regolith bagger provides for constructing temporary radiation shelters for crew when far from the base shelter such as during an extended traverse in the pressurized rover. Since the regolith bagging and stacking process can take a significant amount of time, it must be started somewhat before a solar storm.

Currently the ability to predict solar flares is somewhat limited, and warnings are best provided by surveillance of the sun. Warnings of solar storms may be as short as half an hour. Earth-based support can also be limited or nonexistent; for example, when Mars is on the opposite side of the Sun from the Earth. Improved ability to predict solar storms can reduce risks to crew since operations can be restricted during high alert periods. Radiation protection garments provide emergency partial protection when the crew does not have enough time to return to the habitat or construct a haven. The period of maximum flux of a solar storm is often on the order of a few hours. In such situations these garments give enough protection to limit exposure to tolerable levels for short periods of time. Such garments could consist of about 3 inches of multilayered carbon fiber and provide about 8 grams per square centimeter of shielding. This would reduce the dose rate of a solar flare by a factor of five to seven times that of an unshielded suit. During an event like the 6-hour peak of the August 1972 storm, one of the largest on record, they would allow for an emergency dose of about 10-15 rem as compared to 72 rem. However, they could not support an entire flare period but would give crew added time for more appropriate measures.

Including one propellant plant (150 t LOX/yr), base power needs are estimated to be in the 700-900 kWe range. Nuclear plants are favored at higher power levels because of their reduced mass. The lunar design envisions an SP-100-type reactor deployed in a cylindrical excavation with an aluminum bulkhead for protection from dust. This allows freer placement of the reactor relative to habitats and permits crew maintenance of radiator panels. Six high efficiency free piston Stirling engines running at 91.7 percent of capacity and two reserve engines ensure dependable power generation. Vertical spoke-wheel radiator panels and mercury heat pipes provide waste heat rejection. A PV/RFC power systemprovidesfortheearly base and emergency backup. A nuclear power plant concept for Mars will be determined in FY1989 studies.

The pad area is located several kilometers away to minimize blast effects. Analyses indicate that within 400 m, metal objects will experience significant pitting and glass surfaces will experience damage within 2 km. Permanent pads require surface stabilization such as gravel, paving tiles, or compaction. Gravel created as a byproduct of propellant production is a promising option. Pad markings and navigation aids help pilots and automated landers to find the pads and make precision landings. The devices envisioned are lightweight and contain a transponder, a visual marker, and a light. A retroreflec-tor aids the use of a laser rangefinder. Since operation is infrequent and for short duration, power requirements are minimal. A number of specialized vehicles support pad operations. The construction crane is used to load and offload cargo to the truck. A propellant refill vehicle and power carts service the lander with fuel and auxiliary power.

The use of in situ resources offers great potential for bootstrapping and leveraging growth. FY 1988 activities focused on propellant plants for the surfaces of the Moon, Mars, and Phobos. Each is designed as a self-contained unit that includes its own power supply.

The lunar plant is baselined to use the hydrogen reduction of ilmenite process to produce oxygen from lunar regolith. Ilmenite is an iron titanium oxide whose two chief sources are high titanium basalts and mare soils. The ilmenite content of soils varies: about 7 percent by weight represents a typical value for rich deposits. Basalts can contain substantial ilmenite (the richest Apollo mare basalt samples contained about 33 percent by weight). Since the basalts require substantial crushing and grinding to release the ilmenite particles, the mare soil is preferred. Ilmenite reacts endothermically with hydrogen to produce water, iron, and titanium dioxide. Sufficient reaction rates require elevated temperatures. It has been reported that about 70 percent of the oxygen is removed after one hour at 1000°C. In the envisioned design, automated excavator vehicles mine the ore and deposit it into grizzly scalpers. A continuous conveyor carries the feedstock to the beneficiation process where the slightly magnetic ilmenite particles are removed with high intensity magnetic fields. If basalt feedstock is used, it is crushed, ground, and sorted before separation. Soil feedstock requires additional sorting and larger magnetic separators. Processing is done by feeding the ilmenite through low and high pressure hoppers into a three-stage fluidized-bed reactor. Most of the reaction takes place in the middle bed. Residual solids from the last bed are discarded through a solid gas separator after being used to preheat the material in the first bed. A solid state electrolytic cell dissociates the water into oxygen and hydrogen. The oxygen is liquefied for use as rocket propellant and the hydrogen is recycled. A pilot plant producing about 2 t/mo and powered by PV/RFC with a 35 percent duty cycle (daytime operations and hot standby at night) is estimated to weigh about 22.5 t. A 12.5 t/mo plant using nuclear power on a 90 percent duty cycle is estimated to weigh about 47.5 t.


5.1 POWER SYSTEMS

5.1.1 SP-100 Nuclear Power System Conceptual Design for Lunar Base Applications

The objective of this study was to provide a conceptual design of a nuclear power system using an SP-100 reactor and Stirling engine conversion for use on the lunar surface. System configurations were selected for their ability to enable and/or enhance a lunar base mission. Numerous system components and coupling options were examined and recommended options were chosen for safety implications, high performance, low mass, and ease of assembly.

Background. This conceptual design study was performed as a result of a request from the Propulsion, Power, and Energy Division in the Office of Aeronautics and Space Technology (OAST). The design includes system performance and sizing data, as well as layout rationale. An artisf s rendering of the nuclear power system as it applies to a typical mature lunar base was included as part of the study (figure 5.1.1-1). Because of obvious implications to the Office of Exploration (OEXP) case studies, the conceptual design study was extended to provide an evaluation of nuclear power system impacts on an advanced lunar base.

Key Assumptions.

a. Mature lunar base with power requirements in the 700-900 kWe range
b. Presence of rovers for construction and maintenance
c. Advanced technologies, including the SP-100 reactor, free-piston Stirling engines, and mercury heat-pipe radiators
d. Nuclear power system supplies electrical power only; the use of thermal energy from the power system will be examined in future studies
e. Use of lunar-soil shielding designed to meet human safety requirements

Approach.

This conceptual design was developed using Lewis Research Center (LeRC) experience with the SP-100 reactor and Stirling engines. A critical aspect of the study was to gain an understanding of the lunar environmental conditions and to identify their impacts on the design of the power system. To more fully understand the interactions of a reactor power system with a lunar base, a possible mature lunar base concept was defined with the assistance of the OEXP Surface Systems Integration Agent. The study was a 3-month in-house effort of LeRC's Advanced Space Analysis Office (ASAO) and Power Technology Division (PTD).

Findings.

Lunar Base Assumptions. The lunar base concept is derived from studies performed at the Johnson Space Center. The central core of the base is comprised of two inflatable, spherical modules for habitation and scientific research. These modules are partially buried and shielded from cosmic radiation. Adjacent to the inflatable structures is a rover storage and recharging facility. The inflatable modules and rover facility can be seen in figure 5.1.1-1 in the upper right corner.

A lunar soil processing plant producing oxygen is located approximately 5 kilometers from this habitation area. Lunar soil is transported to this plant after it has been collected from a nearby mining site. A launch and landing facility is located within a kilometer of the oxygen plant. The proximity of the launch pad to the processing plant enables oxygen for propellant to be delivered quickly to orbit for use in chemically propelled transfer vehicles. The processing plant and landing pad are located in the upper left corner of the figure.

Power Requirements. A solar photovoltaic (PV) power system with regenerative fuel cells is assumed to meet the power requirements of the initial habitat module (25 to 100 kWe). As the base expands to include scientific experimentation, rover recharging, and soil processing, a nuclear power system becomes the most viable means of meeting the higher power requirements.

The processing plant will be the predominant power load. For the purpose of this study, that requirement takes the form of electrical power for electrolysis of water, following a hydrogen reduction of lunar ilmenite. The thermal energy requirements of the processing plant would also be provided by the nuclear power system through electrical resistance heating. For an oxygen production capability of 25 t/m, the plant would require 740 kWe, or 90 percent of the nuclear system output.

The remainder of the electrical power generated by the nuclear system would be distributed to the habitat and science modules for life support, to the science laboratory for experimentation, and to the rover storage and recharging facility.

Nuclear Power System Design. The nuclear power system is designed with an emphasis on safety and reliability. It is shown in the foreground of figure 5.1.1-1. This conceptual design consists of a 2500 kWe SP-100 reactor coupled to eight free-piston Stirling engines. The reactor is identical to the design currently baselined in the SP-100 program, whereas the Stirling engines replace the thermoelectric power conversion system of the present SP-100 design. Two of the Stirling engines are held in reserve to provide engine backup for dependable power generation. The remaining six engines operate at 91.7 percent of their rated capacity of 150 kWe. The design power level for this system is 825 kWe. The system is modular and can be replicated in increments of 825 kWe to meet higher power requirements.

It would also be possible, and perhaps desirable, to replicate this system design and operate the two systems at reduced power levels to meet the 825 kWe power requirement. If one reactor power system needs to be shut down, the other system could compensate for the loss in power. As power requirements increase, the capacity of the systems could be gradually increased to meet the higher power levels.

The Stirling engines are arranged in a spoked-wheel configuration and share a common heat transport manifold with the reactor. Each engine is equipped with a pumped heat-rejection loop connected to a mercury heat-pipe radiator. The radiator panels are arranged in a vertical configuration and extend radially from the Stirling engines. A thermal apron is placed between the panels to reduce the lunar surface temperature and thus reduce the required radiator area. The total mass of the system, including power conditioning and transmission lines, is 20t.

The reactor is located in an excavated cylindrical hole which provides shielding from gamma and neutron radiation. The use of lunar soil eliminates the need to transport heavy terrestrial shielding materials to the lunar surface. A boral bulkhead with a domed cap maintains a dust-free environment for the reactor.

Safe radiation levels are maintained in all directions around the power system. This allows for flexibility in choosing a reactor site. The excavated shield design also allows for periodic maintenance on the system's radiator panels. For this conceptual design, the nuclear power system has been placed 1 km from the habitation area and approximately 4 km from the processing plant.

A Fall of Moondust

     It was at least two years since Lawrence had been inside an igloo. There was a time, when he had been a junior engineer out on construction projects, when he had lived in one for weeks on end, and had forgotten what it was like to be surrounded by rigid walls. Since those days, of course, there had been many improvements in design; it was now no particular hardship to live in a home that would fold up into a small trunk.
     This was one of the latest models—a Goodyear Mark XX—and it could sustain six men for an indefinite period, as long as they were supplied with power, water, food, and oxygen. The igloo could provide everything else-even entertainment, for it had a built-in microlibrary of books, music, and video. This was no extravagant luxury, though the auditors queried it with great regularity. In space, boredom could be a killer. It might take longer than, say, a leak in an air line, but it could be just as effective, and was sometimes much messier.
     Lawrence stooped slightly to enter the air lock. In some of the old models, he remembered, you practically had to go down on hands and knees. He waited for the “pressure equalized” signal, then stepped into the hemispherical main chamber.
     It was like being inside a balloon; indeed, that was exactly where he was. He could see only part of the interior, for it had been divided into several compartments by movable screens. (Another modern refinement; in his day, the only privacy was that given by the curtain across the toilet.) Overhead, three meters above the floor, were the lights and the air-conditioning grille, suspended from the ceiling by elastic webbing. Against the curved wall stood collapsible metal racks, only partly erected. From the other side of the nearest screen came the sound of a voice reading from an inventory, while every few seconds another interjected, “Check.”
     Lawrence stepped around the screen and found himself in the dormitory section of the igloo. Like the wall racks, the double bunks had not been fully erected; it was merely necessary to see that all the bits and pieces were in their place, for as soon as the inventory was completed everything would be packed and rushed to the site.
     Lawrence did not interrupt the two storemen as they continued their careful stock-taking. This was one of those unexciting but vital jobs—of which there were so many on the Moon—upon which lives could depend. A mistake here could be a sentence of death for someone, sometime in the future.
     When the checkers had come to the end of a sheet, Lawrence said, “Is this the largest model you have in stock?”
     “The largest that’s serviceable” was the answer. “We have a twelve-man Mark Nineteen, but there’s a slow leak in the outer envelope that has to be fixed.”
     “How long will that take?”
     “Only a few minutes. But then there’s a twelve-hour inflation test before we’re allowed to check it out.
     This was one of those times when the man who made the rules had to break them.
     “We can’t wait to make the full test. Put on a double patch and take a leak reading; if it’s inside the standard tolerance, get the igloo checked out right away. I’ll authorize the clearance.”

From A Fall of Moondust by Arthur C. Clarke (1961)

Sample Lunar Base 2

This is from the US Army's report (1959) on Project Horizon about establishing an Army base on Luna by the end of 1966. Apparently the project was not pursued because the US Army could not explain what exactly were the military applications of such a base.

Sample Lunar Base 3

This is from Lunar base synthesis study. Volume 3 - Shelter design Final report, North American Rockwell's study on constructing a lunar base.


Base is composed of eight modules arranged in a closed-loop circular floor plan. Base has 736 cubic meters of space and 232 square meters of floor area. The modules are designed to operate autonomously, but in pairs to improve efficiency. For instance, the three crew modules provide atomospheric and crew services to the lab module, the assembly-recreation module, and the base maintenance module.

The base has an estimated mass of 27,000 kilograms, without supplies.

There are three crew modules. Each houses four crew plus one other major function. Each of the four crew has an individual stateroom with 3.7 square meters of floor. Staterooms have a bunk, desk, chair, and storage closets. The major functions shared in the crew modules are: Command and Control center, Medical facility, Backup galley and backup control center.

The garage module accomodates the prime mover for repair or maintenance. It is also used by the space tug as a shipping container to transport the prime mover (or other mobile unit) to the lunar surface.

The warehouse module is used as a shipping container by the space tug to transport cargo to the base. Then it becomes a general storage module for the base.

The maintenance module provides facilities for the repair and maintenance of all base systems. It has an electronic area, a mechanical area, and a suit area. It also has an EVA port with an airlock large enough to accomodate six spacesuited crew at a time. This inclueds an air shower and multifiltration system to cope with lunar dust. The airlock can connect to the airlock on a prime mover, for shirt-sleeve transfer of crew.

The assembly / recreation module includes the main galley with food preperation and preservation facilities. It also contains a four crew airlock, with dust control. It also can dock to a prime mover for shirt-sleeve transfer.


The base is constructed of lunar base modules. The modules are 9.2 meters long, 4.6 meters in diameter, and have a dry mass of 4,500 kilograms. They have docking ports on each end. Modules are delivered by space tugs and assembled by prime movers.

Atomic Rockets notices

This week's featured addition is MOVERS Orbital Transfer Vehicle

This week's featured addition is UM Lunar Transport

This week's featured addition is Afterburner fission-fragment rocket engine

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