A Lunar Space Station by
UNIVERSITY OF VIRGINIA
NASA/USRA Advanced Design Program
Summer Conference 1989

Project Overview:

As part of the ambitious space exploration program that has been proposed for the end of this century and into the next, the return of humans to the moon is one of the primary objectives.
In order to accomplish the goal of a permanent moon base, a large support structure must be developed to provide the lunar residents all the materials and equipment that they will need to properly use the moons abundant natural resources.
Our Aerospace Vehicle Design team feels that one of the essential elements of this support structure is an orbiting Lunar Station similar to the earth station Freedom. With the above considerations, we are proud to propose a space station concept for the low lunar orbit.

The Lunar Space Station (LSS) is a complete support facility that will have the ability to provide the surface base with fuel, water and equipment ferried from earth.
An added purpose of the station will to experiment with manufacturing using lunar materials. Taking advantage of the zero-gravity environment, this facility will produce a superior grade of GaAs crystals for the construction of semi conductive devices.
The abundance of silicon oxide and other silicates also allows for the mass production of fiberglass at a high profit margin. Additionally, vegetation of various kinds will be grown on-board. They will have an active role in the air and food cycles of the life support system. These along with other minor experiments will attempt to demonstrate the commercial applications of space exploration.
The obvious design problems, in this case, are the power requirements, space hazards, profitability of the industrial processes and the prolonged zero-g effects. Our project will attack these problems with design concepts and solutions that are feasible with today's technologies. The single obstacle in realizing this project would be the high cost today's space transportation systems.

The mission of this project is divided in 5 Sub phases:
SUBPHASE 1: Initial start-up of Lunar Space Station. First habitation module, cryogenic storage facility, and one lander will be put into lunar orbit.

SUBPHASE 2: Second habitation module along with the Communication and Control Module will be transported to LLO. Permanent manned operation will also be started.

SUBPHASE 3:
Medical/Health Module and miscellaneous truss components will be transported and assembled in LLO.

SUBPHASE 4: Agricultural Module, furnace, and remaining supporting Structures will be assembled in LLO in this stage.

SUBPHASE 5:
Completion of LSS. Processing Module arrives in LLO. Complete manufacturing operation will start in early 2005.

Design Requirements:
A set of system requirements will now be established for a standard mission scenario.
This will entail a trip from the ground to Low Earth Orbit via a STS such as the Space Shuttle.
Using a fleet of 3 to 4 Orbital Transfer Vehicles (an assumed technology), semi-fabricated components of the Lunar Space Station will be transported to a Low Lunar Orbit. At this point, the remaining construction tasks will be completed in conjunction with the startup of the Lunar Lander Program.

Technological needs and developments:
As an initial concept study, we will propose many innovative and original engineering designs.
They are based on the latest and most current technologies in many fields from agriculture to waste management. Needless to say, advances in these areas will insure the success of our design from an economic standpoint. The following analysis will identify some of our technological needs.

Main modules:
The structure of this space station must provide shelter from the environment of space. The design of any shelter may consist of one large enclosure, several smaller enclosures, or a combination of both.
For example, factories often have wide open interiors to permit movement of machinery and workers while protecting them from the surroundings (e.g. rain, low temperatures, etc.).
A modular structure is most advantageous in the space environment because it has the following characteristics:
Relative ease of assembly, flexibility, and safety. With the modular design, most construction takes place on Earth, and then the whole station is lifted into orbit in large sections.
Minimized extraterrestrial construction is desirable to astronauts because spacesuits are pressurized, and therefore, a hindrance to movement.
Working in a spacesuit for long periods of time is tiring. Also, any extravehicular activity is dangerous because of the harsh environment of space.
A modular station is more flexible because the configuration can be changed, more sections can be added, and others can be removed. All docking hatches are homogeneous so that any two can be joined together.

The Space Station Power System:
Power is of major concern to spacecraft and space station designers.
The life support, communications, and guidance systems need power to operate.
A failure of these systems would likely lead to the death of the astronauts and the loss of the structure. Listed below are the four power supply systems that were considered for this project.
Each is ranked for seven important characteristics, with the total points given at the bottom. The solar dynamic system received the highest score and was therefore chosen as the primary, power generator for the manufacturing facility.
The group decided that the station would require a total of 250 kilowatts of electrical power to operate. Ten units, rated at 25 kW each, will provide the power.

Fuel cells and batteries are unacceptable as primary sources because they need recharging, which requires a second power supply.
Also, the large amount of cells or batteries needed to generate 250 kilowatts makes this choice undesirable. When the SP100 nuclear system is fully developed, it will be able to supply the necessary power with a compact structure.
The photovoltaic system is not a good choice because of the huge arrays needed to collect solar radiation. The solar dynamic system uses solar collectors with a smaller total surface area. Large arrays detract from the maneuverability of the station and can even experience drag from impacting particles. Space does have a low density of particles, but it is not completely empty (especially in low Earth orbit).

The aim of this section is to determine the manufacturing and agricultural processes to be conducted on the lunar space station. The processing is determined based on an established criteria.
This criteria acknowledges the important aspects that influence space processing.

Fiberglass production, growing crystals, and space gardening are the selected processes. Each process is investigated along with the advantages and disadvantages of conducting it in space.
Solutions are offered on the best way to handle any problems that are encountered with processing in space.
The processing section can have overlapping work with the life support section, but it is basically different from the other design components.
The other components' designs are necessary to complete a functioning station. The area dedicated to processing, however, is not required for the survival of the station.
The functions of the processing area are to successfully complete industrial work and to aid in the overall space station support. This entails producing materials to be used on the station, or in other places, and to conduct processes that would help the station be self-supportive and more efficient .
After determining the criteria on which to base the selection, it is necessary to explore the range of possibilities. The range of processes that can be completed in space is quite diversified. It consists of areas such as lifesaving medicines, communications, agriculture, metals, and science.
The knowledge of these diverse areas comes from previous space experiments.
It also comes from research that has been done on Earth to predict the results that would arise in a microgravity environment.

SPACE GARDEN:
The agricultural process of a space garden was chosen as the third process to be done on the lunar station because of its benefits.
The advantages of doing this fit the established criteria. However, the advantages are not just economical, and it does not even use lunar soil.
The main link to the criteria has to do with helping to set up the space station with a regenerative life support system.
In other words, setting up a space garden will help that station be self supportive in areas of food, oxygen, and waste.
This enables the station to function more on its own instead of relying on supplies from Earth.
Since the station is planned to exist indefinitely, its self- sufficiency becomes a major concern.
Not only will this arrangement be beneficial in the case of emergency barring transportation of supplies, it has economical and psychological effects.
Economically speaking, transportation costs will be lowered along with saving money by reusing products on the station. Psychologically and nutritionally, the crew will benefit by eating fresh foods to which they are accustomed.

Environmental Control and Life Support for a Lunar Space Station:
The environmental control and life support system provides for a partial closure for our space station. Partial closure of the ECLSS is based on the processes for closing the air loop and the water loop. A completely closed ECLSS is not possible at this time because of the lack of knowledge concerning food development in space. Research into food development on our station will take place, but our crew will only be able to harvest a small amount of food. Therefore, the re-supply of food is a must.

Air Loop:

The air loop begins with two externally mounted, high pressure storage tanks containing Nitrogen and Oxygen.
The gasses are then sent through separate lines to be monitored by two high pressure atmospheric regulators. The gasses are next sent into the module, where they are mixed together in specific concentrations.
The concentrations are regulated by signals from an oxygen pressure transducers located within the module. Once the gasses are mixed, a control system is used to keep module working conditions reasonable for the crew.

Please refer to the document if interested in the water and waste loop.

SPACE HAZARDS AND EMERGENCY LIFE SUPPORT:
In the design of any manned space vehicle or complex, a number of external and internal safety hazards that may endanger the crew must be considered. In the case of a permanently manned space station, meteor strikes and prolonged radiation exposure are the primary external hazards, while the internal hazards are generally associated with the equipment, experiments, and processes carried on board.
Any of the hazards stated above could lead to situations that would endanger the safety of the station crew.

Internal Hazards:

Equipment failure of any kind on board the space station could lead to potentially dangerous situations that would jeopardize the safety of the crew. These potential emergencies include biological or toxic contamination, electrical fire, chemical fire, general life support equipment failure, etc. The possibility of internally caused danger situations can be reduced by the use of detection sensors and alarms and by the use of functional redundancy in the design of station equipment and processes.
In unmanned missions, the criteria for backup systems installed is cost effectiveness.
In manned missions, the criteria must be crew survival.

Radiation Protection:

Manned space vehicles outside of the geomagnetic field of the earth are subjected to the hazards of the unattenuated space radiation environment.
The radiation comes in the form of galactic cosmic rays from deep space and solar cosmic rays from the sun. Both sources of radiation present a considerable health hazard to the occupants of a manned space vehicle, such as the lunar space station, if they are not properly protected. Inadequate radiation protection can result in discomfort, illness and in extreme cases, death.
Galactic cosmic rays represent a continuous radiation background in interplanetary space and
consist of low intensity, extremely high-energy charged particles. They are composed of approximately 85% proton particles, 13% alpha-particles, and 2% particles of heavier nuclei.
The flux density of the particles between the earth and the moon is between 2 and 4.5 particles per cm2s-1 with energies of 108 to 1010 electronvolts per particle.
They have an unprotected exposure rating between 4 and 12 reins per year due to their low flux (number of particles per unit time per unit volume) and consequently are not considered to be a real danger to station crew members.

The last chapter in this document describes the Physiological
And Psychological Problems of Long-term Spaceflight:

The goal of this thesis project is to determine what we now know about ways to overcome the various physical and psychological difficulties which a space station crew will encounter during extended missions. The findings of this report are used in the design of a moon-orbiting, industrial station, where crew turn-around times are expected to be many months. Before presenting the problems and solutions of living in space, however, it is necessary to first outline the station design project as a whole in order to put this research effort into the proper context.

The station is intended to be an industrial manufacturing facility which will convert lunar soil into useful products such as fiberglass and silicon chips. The station will be assembled in lunar orbit and, once operational, will serve as a staging area for construction of a base on the surface of the moon.
The orbital station will provide support to the lunar base, and will supply some of the materials necessary during its construction. After completion of both orbital and surface stations, the orbital station's mission will expand to include a variety of space manufacturing, such as zero-gravity crystal growing and alloying of metals. The station will also be used to perform research projects suitable to the lunar-orbit environment, such as studies of solar wind and radiation, which cannot be performed in Earth orbit because of the Earth's magnetic field.
The team designing the space station consists of seven members. Each is responsible for several design "specialties," such as radiation shielding, power systems, or life support.

One of the areas of responsibility, and the reason behind this thesis project, is the research of any habitability problems likely to be encountered by the crew of this station and the recommendation of a solution or set of solutions to these problems.
There are numerous obstacles to successful extended space missions. Many of these are the result of the harsh conditions which confront those who must live in space.
The absence of gravity forces, the presence of dangerous radiation, and the cramped and isolated living conditions found in spacecraft are all detrimental to the well-being and productivity of the crew.
In addition to having to deal with these normal challenges of living in space, the crew of the AE 441-442 station will also face several unique problems caused by the lunar-orbit environment. The distance from Earth and the absence of the protection against radiation afforded by the Earth's magnetic field are two problems which are particular to this station.
The space manufacturing mission of the station further compounds problems and requires that special consideration be given to station habitability.
For example, the station must be laid out so that the negative effects on the crew of noises or odors from manufacturing operations are minimized.

The short-term effects of space travel are physiological in nature and become apparent immediately after liftoff.
They are the result of the transition from the conditions on Earth to the zero-gravity environment found in space. They usually pose a problem only during the first week or two of living in space; after this time, the human body compensates for the new conditions and is able to acclimate to the situation.
It is relatively easy to distinguish between the short-term and the long-term physiological effects, because long-term factors do not become noticeable until after several weeks in space. The major short-term problems of living in zero-G conditions are space sickness and fluid redistribution.
One of the immediate problems that has plagued many previous missions is space sickness.
When first exposed to zero-gravity conditions, the human body receives conflicting sensory input, which results in disorientation.
Symptoms of space sickness include nausea, vomiting, and lethargy.
Though few cases have been serious enough to temporarily incapacitate the affected crew member, space sickness is a problem which must be overcome.
Space sickness occurs when the sensory data from the semicircular canals of the inner ear conflict with the sensory input from the astronaut's eyes.
The brain is unable to integrate the conflicting sensations, and the astronaut experiences special disorientation.

The long-term problems of living in space become noticeable after about two weeks in space and get more serious with time. Unlike the short-term difficulties, some of the long-term problems can persist for an extended period after return to Earth.
Also, it is much more difficult to combat the many negative complications of extended living in space.
The most serious detrimental effects are the physiological changes caused by living in zero-G.
Because very little muscle power is required to move about in this situation, the body begins to decondition and the muscles start to atrophy.
Reduced ability for strenuous exercise is detectable in astronauts after as little as one week in space. Muscle atrophy through disuse continues to progress as time goes on, the leg muscles being the most strongly affected. This is because the legs are used all of the time on Earth, but are relatively unused in space. Most movement about the spacecraft cabin is done by pushing off with the arms and then floating.

Conclusion:

This thesis has examined several problems associated with living and working in the space environment.
Specifically, the problems which have been addressed are those that would most likely pose the greatest difficulty to the inhabitants and the designers of the AE 441-442 space station, t3v keeping in mind the issues presented in this paper, those designing this and similar stations will finish with a safer, more habitable, and more productive project.

The habitability problems of space stations have been grouped into three major categories:
short-term effects, long- term problems, and factors which are inherent to the specific mission of the station. To assure the development of a successful project, designers must always take into consideration short-term effects and the specific station requirements. On missions of significant duration, the long-term problems of space living must also be addressed.

This is all too interesting

A friend of mine from graduate school worked as a biologist and consultant to companies developing air supply systems for undersea and space vehicles. At a reunion we were talking shop and he said he was working on a study showing that (in animals) extended exposure to air generated from re-breathers/air scrubbers was in fact quite detrimental, if I remember correctly it was a problem with red blood cell count after the equivalent of 6-9 months exposure. At that time he suggested they were beginning to plan a follow up study to try to find the cause. The primary theory was that the process by which the air was generated might introduce unintended toxicity. But he had his own theory which was that the air was "too sterile" as he put it, he had found some research indicating that normal particulates in air contain bacterial cultures that produce a beneficial immune response from the lining of the lungs helping the lungs transfer oxygen. After very long periods breathing sterile air, the lungs lose some of their function as the bacteria already in place diminishes. Sadly I heard he died a few years later and I never heard what became of his research. I found his theory fascinating. I hope this has been adequately explored/addressed so it doesn't hold us back.

John