SSI Newsletters: 1994 May-June

Space Studies Institute Newsletter 1994 MayJune cover

P.O. BOX 82
[[librarian note: This address is here, as it was in the original printed newsletter, for historical reasons. It is no longer the physical address of SSI. For contributions, please see this page]]





Lunar concrete

Readers of SSI Update know that human settlement of the Moon will be impractical without the use of local resources. Carrying everything needed up from Earth is simply too costly. Research, much of it stimulated and supported by SSI, has already shown pathways toward extraction of oxygen and metals from lunar raw materials, and much more progress in that direction is possible. Also some preliminary work has been done on how to use lunar-derived materials in the construction of useful structures on the Moon, for example by sintering or melting lunar soils and making shaped products, as is done in some places on Earth with basalt castings. What about concrete? Will it ever be possible to make lunar structures resembling the ubiquitous concrete buildings of Earth?

The technology of cement and concrete is ancient. The Egyptians used mortar; the Roman Pantheon is a concrete building. Beginning in the 18th century, modern knowledge of concrete has advanced rapidly to permit the building of tall and graceful reinforced-concrete structures. Using the ability of wet mixtures of calcium oxide, silicates, clays and inert aggregates to bind into a hard, strong material, humans have housed, dammed, paved and bridged to improve their living. On the Moon, a similar development is conceptually possible, and some pioneering steps in the needed research have already occurred. The acknowledged founder of this research is T.D. Lin, working at the Concrete Research Institute near Chicago and at the National Chiao Tung University, Beijing. Lin first made concrete test samples using simulated lunar soils, and after he had done enough tests to determine the special needs and properties of concretes that could be derived from lunar raw materials, he applied for and received small samples of Apollo lunar soil and made good concrete from it.

The essential reactions that cause a cement paste to solidify and bind with an aggregate are complex. Look up “cement” and “concrete” in a good encyclopedia and you will learn a lot. But the central process is hydration, the joining of water with minerals to form new crystalline structures. The needed calcium – and silicon – bearing minerals are available on the Moon (though mostly not in the proportions and forms familiar on Earth), but water, at least in the lunar regions explored to date, is completely absent. How are we going to get the needed water and knowing it to be scarce, how are we going to minimize its use? Some water may indeed be hauled up from Earth, to be used in recycling life-support systems. But it seems unlikely that we will want to bring water up and then sequester it in lunar concrete structures. It may be better to bring up hydrogen to be combined with lunar oxygen, or else to extract solar-wind hydrogen from lunar soils and use that. Even if the ultimate lunar bonanza, water in shadowed craters at the poles, is found, we will want to minimize the amount of water in any concrete that we make on the Moon. Thus there is a grand research opportunity for the development of unconventional concrete-making and concrete applications. Some preliminary work has begun. At the Shimizu Corporation in Japan, various simulated lunar concretes are under test. Students at the U.S. Air Force Academy have investigated steam injection, and similar small research projects are going on elsewhere. To continue his advocacy and focusing of such efforts, a few years ago T.D. Lin led the formation of a lunar concrete committee at the American Concrete Institute, and as a Moon enthusiast I was invited to join.

At its latest meeting, which I attended in San Francisco on 21 March 1994, the committee surveyed current activities and plans and came up with several suggestions for near-term actions that can help to maintain progress. T.D. Lin will accept proposals for one graduate-student research position at the National Chiao Tung University. (He now spends the academic year there and the summer at his home near Chicago.) Other student activities will be encouraged through SEDS (Students for the Exploration and Development of Space,) and the NASA-sponsored Advanced Design Program of USRA (The Universities Space Research Association). One SEDS chapter, at the University of Alabama in Huntsville, is already involved in preparing a getaway special for a Shuttle flight this year, with a small mixer to investigate concrete formation in microgravity. A prototype of this experiment was on display in San Francisco.

At JPL some years ago, Joseph Bruman investigated the behavior of mud in a vacuum. If you put a can of mud into a vacuum chamber and pump it down, the pore water first forms small geyser channels and snow fountains, developing a cheesy top surface on the mud. But soon these channels clog as ice freezes in them, and the porous layer acts as good thermal insulator. If heating, simulating sunlight, continues from the top, eventually the ice plugs sublime away and geyser fountaining resumes. But meanwhile the lower portion of the sample has continued to be wet mud. At the time, nobody thought of this as potential lunar concrete, but now it clearly deserves to be investigated. Small experiments, of the kind that can be done in a university laboratory, with proper control of the relevant variables, might show whether or not outdoor concrete production is feasible on the Moon.

J.D. Burke


Space Studies Institute Newsletter 1994 May-June SPS Research

We are pleased to announce that the final report, “Low Mass Solar Power Satellites Built from Lunar or Terrestrial Materials,” by Dr. Seth Potter, is now available. The purpose of this SSI research project was to design a lightweight solar power satellite (SPS) which made use of thin-film photovoltaic materials and solid state transmitters deposited on lightweight substrates. If the design was feasible, the task was then to redesign the SPS to make use of lunar materials.

Dr. Potter has been successful in both phases, designing an SPS which has less than 100% of the mass/kilowatt (a 90% reduction in mass!) than the former NASA/DOE and SSI designs. This breakthrough can make manufacturing and deployment of the SPS much more feasible and economical. Senior Associates were sent a complimentary copy of the report, and anyone else wishing to receive a copy of the final report may order one from SSI by sending $9.95 to SSI with your request.



By Judith Fielder and Nickolaus Leggett

If we are going to colonize space and not merely visit it we will need to grow plants in space successfully. Agricultural systems will need to be an integral part of the ship, the space station, or the planetary base, not merely an add-on, or an afterthought. The use of growing plants is not only a logical way of providing food, recycling air, water, and solid waste but even, as mission time increments increase, a very efficient way. Development of such plant systems would be a priority on par with the development of space habitat hardware.

Current plans for space agricultural and plant systems present highly specialized, automated, highly controlled, pre-specific systems with little room for environmental adaptation, or mid-cycle corrections and changes. This type of design is neither suited nor practical for first generation systems in a new space environment.

An ideal first generation plant system would be a hands-on, open access system with a wide variety of configurations possible with multiple modes of operation. The basic design should be simple and suited to manual intervention. The components of the system should be designed to be repaired and reconfigured by crew members as desired. Tolerances should be built into the systems to allow for unpredictable fluid flows, microbiotic activities and contagions, and unpredictable physiological responses on the part of the crop plants. The variety of crop plants should not be reduced in number or pre-screened before adequate testing has occurred in situ. This design philosophy is a major departure from the typical aerospace approach of providing sealed, pre-screened, pre-tested, pre-selected, non-repairable modules for the astronauts to use. It is likely to require numerous adaptive steps and in situ trials before space agriculture and space colonization can truly proceed.

Plant Selection

Plant selection should not be based solely on performance of a plant in the terrestrial environment. There will undoubtedly be physiological responses of some plant types to various space environments making some plant selections undesirable. Aside from the physiological response is the food and nutritional value of the crops. A wide variety of crops is recommended both for esthetics and nutrition. Plant growth habits, maturation rates, and crop size are also considerations as is the impact on the space or planetary habitats of the growth cycles. Mass flow fluctuations tend to be designed out and ameliorated far more efficiently with a wide selection of plant types. While crops such as wheat are of interest to space habitats they should not be considered primary prospects for space plant systems as there are post-harvest processing requirements, high percentages of wastes, and significant mass flow fluctuations associated with their cultivation.2

Cropping Practices

There are numerous cropping practices available for experimentation in the space environment.4,5,6,7,8,9,10 Some are more amenable to diversity than others. The space environment tends to favor high density planting with a large number of plants per unit area in a stacked configuration 5,7,9 to preserve pressurized volume in the space habitat. Solid medium substrate agriculture is amenable to intensive multicropping of several plant types with different maturation periods. Hydroponic systems are amenable to intensive cropping but favor monocropping with some serious draw­backs in variety of crops that can be successfully grown.

Plant Growth Requirements

Plants have specific requirements that need to be met for successful growth. (See Table 1.)

Table 1. Plant Growth Requirements
Parameter Requirement
Light 200-400 watts/square meter
400-800 nanometer range
infrared minimized
adjustable day/night cycle
Air Nitrogen, oxygen, carbon dioxide mix
Ambient pressure 850-1000 mb
C02 levels > 100 ppm < 1000 ppm
Multidirectional breezes 6 km/hr
Temperature 15°C-32°CCapacity for occasional 0°
Water and Nutrients Humidity 50-95%
Constant availability of water to growing plants
Nutrients in sufficient quantities to obtain desired yields
Magnetic Field? Possible requirement for a constant magnetic field
Ionizing Radiation Protection from ionizing radiation

These requirements are stricter than most space industrial processes would require. All requirements must be met constantly to ensure proper plant growth. In addition, plants must be protected against toxic substances and explosive decompression events.

Many of the materials needed for plant growth can be obtained from space to avoid the cost of obtaining them from Earth. A lot may be by-products from space industries. Use of plant growth systems that can handle a variety of feedstock is recommended.


Microgravity Agriculture

Aeroponic agriculture will be extensively used in microgravity environments where soils are not initially available. However, solid medium agriculture should be considered as an alternative with plants growing in containers of composted crops wastes both as a method for recycling crop and human wastes and for preserving a large population of microbes.

In microgravity agriculture plant roots must be artificially aerated or the plant will drown. In a gravity environment with soil­-based agriculture, the water flows down a gravity well providing air access to the roots. In microgravity, the water clings to the roots. Artificial flows of air and/or aerated water to the roots are required frequently. These flows can be utilized to provide a directionality for the plant roots in the absence of a gravity stimulus.

The plants must be allowed to grow freely while water and nutrients are effectively contained. This can be accomplished by providing flexible structures that the seedling plants grow up through.4


Regolith-based Agriculture

Although numerous cropping systems can be utilized on the Moon, lunar bases will probably use agriculture with plants growing in processed and amended lunar regolith.3,6,7,8,9 Regolith will be mixed with organic matter and nutrient additives to become an engineered soil for growing a wide variety of plants. This soil offers a buffering of moisture, nutrients and stable temperatures. This stability makes agriculture an easier activity that it would otherwise be. The lunar habitat needs this reliability that is offered by this soil. Hydroponic and aeroponic agriculture do not offer this inherent stability of operation.


Recycling and Composting

One of the primary services that the plants provide is the recycling of organic waste materials into food. Plants can take crops wastes, human wastes, paper, and dead bodies and turn them into food. The best way to do this is to use a two-stage process. The first stage is a microbial degradation of the wastes into an organic product (compost). This compost is utilized by the growing plants.

Gravity soil-based agriculture uses compost easily. A combination of a composter and agriculture in trays or engineered soil effectively uses organic wastes. This combination offers a highly reliable process that would be appreciated in a planetary settlement.3

Microgravity systems utilizing compost will be more complex5 but are feasible.


Mass Flow Fluctuations

Mass flow fluctuations are a significant problem for space agriculture.2 Mass flow fluctuations occur when you remove a growing plant from the agriculture system. When you harvest a crop it ceases to recycle water and wastes. The harvested crop stops consuming carbon dioxide and begins to produce it, and stops producing oxygen and begins to consume it.

Different plant types affect mass flow differently. Crops such as wheat, where a whole plant is harvested in large numbers, affect the mass flow more substantially than crops such as tomatoes and peppers where individual fruits are harvested but the plant remains intact and growing. Plants with low carbon to nitrogen (C/N) ratios such as lettuce have less impact than do plants with higher C/N ratios such as wheat. Utilization of numerous small harvests of a variety of different crop types would both reduce mass flow fluctuations and ensure a continuous food supply.


Contagion Control and Emergency Containment

Pathogens will contaminate the agricultural facility. The facility must be designed to contain the spread of pests and to decontaminate contaminated areas.1 Waste water should be heat treated to remove harmful microorganisms. Feed water should be filtered or exposed to ultrasound for a similar purpose. Handling systems can be provided to isolate plant growth trays that are infected with diseases and transport them to a sterilization area.

Redundant agricultural systems in separate areas can ensure a reliable food supply in case of serious contamination of one of the areas. Several months’ supply of freeze-dried food will add to the food supply security.


Materials Handling

Any type of space agriculture system will require materials handling systems for harvesting, planting, and maintaining the growth medium.1 Hydroponic systems circulate the liquid growing medium. Solid-medium agriculture requires systems for moving the soil and mixing the soil with composted material. All systems require systems for handling plant products and wastes.

Air moving systems are required to circulate fresh air to the plants and to help remove waste heat from the lights. The air moving system must be designed to provide changing “wind” directions to the plants for strong and even plant growth.

Periodic showers for leaf cleaning are required for best photosynthetic efficiency in any agricultural system.



All aspects of a plant agriculture system need to be studied and adapted to the environment it is intended for. As more information becomes available in situ better choices can be made as to plant selection, performance, and reliability. Until such a time as reliable in situ information is available space agriculture systems should be designed to be flexible and adaptable.



1. “Materials Handling for Lunar Base Agriculture,” 11th Biennial Space Studies Institute/Princeton Conference on Space Manufacturing, Princeton, NJ, May 1993.

2. “Impact of Agricultural Mass Flow Fluctuations on the Lunar Base Environment,” 10th Biennial Space Studies Institute/Princeton Conference on Space Manufacturing, Princeton, NJ, May 1991.

3. “Composting for Lunar Agriculture,” Space 90 Conference on Engineering, Construction, and Operations in Space, Albuquerque, New Mexico, April 1990 (American Society of Civil Engineers).

4. “A Hydroponic Design for Microgravity and Gravity Installations,” Vision 21, Space Travel for the Next Millennium, NASA Lewis Research Center, Cleveland, Ohio, April 1990. NASA CP 10059.

5. “A System for Recycling Organic Materials in a Microgravity Environment,” 9th Biennial Space Studies/Princeton, NJ May 1989.

6. “Lunar Agricultural Requirements Definition,” poster paper at the Space 88 Conference on Engineering Construction, and Operations in Space, Albuquerque, New Mexico, August 1988 (American Society of Civil Engineers).

7. “A Second Generation Lunar Agricultural System,” Journal of the British Interplanetary Society, Vol. 41, pp. 263-268, June 1988.

8. “Considerations for First Generation Lunar Agriculture,” presented at the Conference on Lunar Bases and Space Activities in the 21st Century, Houston, Texas, April 1988.

9. “Lunar Agricultural System Design Considerations,” poster presentation at the 18th Lunar and Planetary Science Conference, Houston, Texas, March 1987 (NASA -Lyndon B. Johnson Space Center).

10. “Space Greenhouse Design,” Journal of the British Interplanetary Society, Vol. 37 pp. 495-298, 1984.




SSI is cosponsoring two upcoming conferences: The National Space Society Conference in Toronto, Canada, May 27-30, and The Planetary Society Conference in New York, NY, August 29-September 1, 1994.

The National Space Society Conference is the 13th in the series of Space Development Conferences and will feature an evening program commemorating the twentieth anniversary of Dr. O’Neill’s first Princeton Conference on Space Manufacturing in May, 1974. SSI will host a hospitality suite on Saturday evening, May 28, following the program. For more information, please contact Paul Swift at xxx-xxx-xxxx.

The Planetary Conference Practical Robotic Interstallar Flight: Are We Ready? is now accepting abstracts. The conference will be held at New York University August 29-September 1. For more information about paper submissions or conference registration, please contact Dr. Edward Belbruno at xxx-xxx-xxxx, xxx-xxx-xxxx FAX, <>. The deadline for abstracts is May 15, 1994.



Living and Working in Space: The Countdown Has Begun – the PBS special featuring the last interview conducted with Dr. Gerard O’Neill, is available through FASE Productions. The thought-provoking, entertaining, and inspiring production looks at possible scenarios in the near future. It has won six awards. To order a copy, call xxx-xxx-xxxx or Lori Nasi at xxx-xxx-xxxx. The price is 14.95 plus $5.00 shipping for a single tape, $.50 for each additional tape.



Space Studies Institute Newsletter 1994 May-June soviet


The Space Business Archive, a Space Studies Institute program, is pleased to announce the availability of the NPO Energia Guide to Products and Services and MIR 1 Space Station: A Technical Overview. The first book, (NPO Energia Guide to Products and Services) is a 172-page document translated into English from Russian and includes technical descriptions of equipment and general specifications for all major NPO programs, including the MIR 1 space station, experiment requirements, microgravity, the Energia launch vehicle, the Soyuz transport ship and the Progress supply vehicle. The guide also includes information on the engineering and consulting services available through Energia’s team of highly qualified and respected specialists. A large array of non-aerospace products and services are also listed including testing facilities, promotional services, and consumer products.

MIR 1 Space Station: A Technical Overview is a 200-page document also translated from Russian into English which details lessons learned, remote sensing, reentry technology, docking systems, mission control and MIR 1 experiment requirements.

To order copies of the guides, please send $79.00/guide or $142.00/set plus shipping ($5.00 US, $15.00 non-US addresses) to SSI/SBA, P .0. Box 82, Princeton, NJ 08542. You may order by phone, FAX or E-mail using a Master­Card or Visa: xxx-xxx-xxxx; or E-mail Please be sure to include a daytime phone number and the book requested on all correspondence.



Dr. Roger O’Neill, Chairman
Prof. Freeman Dyson, President
Dr. Joseph P. Allen
Mr. Junta Ayukawa
Mr. James Burke
Mr. Morris Hornik
Mr. Gregg Maryniak
Mr. William O’Boyle
Dr. Fred Rose
Dr. Lee Valentine


Mr. James Burke
Prof. Freeman Dyson
Mr. W. Brandt Goldsworthy
Ms. Bettie Greber, Executive Director
Mr. James Laramie
Mr. Gregg Maryniak
Mr. William O’ Boyle
Ms. Tasha O’Neill
Dr. David Odom
Dr. Fred Rose
Dr. Lee Valentine
Mr. David Wine


Col. J. Paul Barringer
Barringer Crater Company

Mr. Richard Boudreault
Technologies Aerospatiales

Dr. William Brown

Raytheon, retired

Mr. Christopher J. Faranetta
NPO Energia, Ltd.

Mr. George Gallup, Jr.
Gallup International

Mr. Richard E. Gertsch
Colorado School of Mines

Mr. Alex Gimarc
Anchorage, Alaska

Dr. Peter Glaser
A.D. Little

Mr. James Harford

Ms. Kathy Keeton
OMNI Magazine

Mr. Jeffrey Manber
NPO Energia, Ltd.

Dr. Rashmi Mayur
United Nations

Mr. Burt Rutan
Scaled Composites, Inc.

Mr. Steven Vetter
Minneapolis, MN



The Space Studies Institute is a non­profit, international, research and educational organization. Founded in 1977, it is dedicated to opening the high frontier of space.

SSI’s goals include using the material wealth and solar energy of space to improve the human condition both for those who live on Earth and those who live in space, and to build Earth-like habitats in space to expand the ecological range of humanity throughout the solar system and ultimately, perhaps, through­out the galaxy.

To this end, SSI has conducted and is conducting pioneering research into advanced space propulsion, the extraction and processing of nonterrestrial materials for engineering purposes, and the identification and location of lunar and asteroidal resources.

Following are four opportunities for participation in SSI activities:

Corporate Membership

SSI’s Corporate Membership program offers access to SSI’s broad base of technical advisors, access to a resume pool, and access to exhibit space at the biennial SSI Conference on Space Manufacturing. Research partnerships are encouraged.

Senior Associate Program

The Senior Associates Program is currently SSI’s largest source of funds for High Frontier research and education. The program also provides a way for anyone interested in the High Frontier to play a key role in making space colonization and space manufacturing achievable within our lifetimes. Following is a description of the program.

The Senior Associate program was created in 1979 to generate the steady funds that SSI needs to conduct research projects, most of which require money for several years. Today we have about 1,000 active Senior Associates; 537 Senior Associates are on their second, third, or fourth pledge. The program provides about 60% of SSI’s annual budget and is essential to both our research and educational activities.

Senior Associates receive special benefits as our thanks for their support. These benefits include invitations to special events, free mailings of publications by SSI, NASA, and other space organizations; and confidential newsletters, describing SSI developments before they are made public.

However, most people become Senior Associates because they want to see space colonization become a reality; they give much­needed funds and join the group of people working to create the High Frontier in our lifetimes. As Senior Associates, they also meet others who share their enthusiasm for space exploration and development. Each Senior Associate makes a five-year pledge to SSI, choosing one of the ranks below:

Associate: $100.00 annually
Fellow: $200.00 annually
Colleague: $300.00 annually
Distinguished Colleague: $500.00 annually

Payments can be made annually, semi­annually, quarterly, or monthly.

Each Senior Associate receives a number with his or her rank, indicating when he or she joined the program. For example, the next person to join could become Fellow 368, or Distinguished Colleague 126. Each Senior Associate receives a certificate, signed by SSI’s president, as a permanent record that he or she was one of the first people who gave critical support to the High Frontier. The names of the Senior Associates will also be permanently maintained by SSI to provide historians with the names of early High Frontier supporters.

Regular Membership

SSI Membership is open to individuals worldwide. All members receive the lnstitute’s newsletter, which is published bimonthly and keeps all SSI members abreast of SSI research, an SSI membership card and decal. Membership fee: Regular $25.00; Senior Citizen or Student $15.00; non-US addresses, please add $10.00.

For gifts of $50.00 or more, you will receive an SSI lapel pin.

With gifts of $100.00 or more, you will receive a copy of Dr. O’Neill’s book, The High Frontier.

Volunteer Program

As a nonprofit organization, SSI relies on the expertise of many volunteers worldwide to assist in the areas of research, education, presentations, development of visual arts, and technical writing.

If you are interested in the future in space, contact SSI by letter, phone, FAX, or E-mail:

Space Studies Institute
P.O. Box 82
Princeton, NJ 08542.
Phone: xxx-xxx-xxxx

[[librarian note: This address is here, as it was in the original printed newsletter, for historical reasons. It is no longer the physical address of SSI. For contributions, please see this page]]

©space studies institute

NEXT: Jul-Aug 1994 (Waveguide Solar Lunar Processing, William Brown Power Beaming demo)

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Technology for Human Space Settlement