SPC #20: Moon Construction

Welcome to the Sunday Paper Club. Every Sunday, this blog will offer an analysis of a paper on space habitation and other related topics. These are my opinions on a weekly scientific paper; basically, I read the paper and write down my thoughts while I read it. They are subject to my perspectives and believes. I am open to debate, so if any reader believes I have misinterpreted something in a paper, please point it out. I'm only a student and I'm still learning how to read these papers and interpret them. All quotes and ideas are from the paper, unless otherwise noted.

This week we are reviewing the paper Engineering, Design and Construction of Lunar Bases. I am using a new format based on the Lifehacker article Back to School: Keep an Academic Reading Journal.

Article Information

Title: Engineering, Design and Construction of Lunar Bases

Author(s): Haym Benaroya, Leonhard Bernold and Koon Meng Chua

Date: April 2002

Journal: Journal of Aerospace Engineering

Volume: 15

Issue: 2

Pages: 33-45

Article Overview

Building on the moon is harder than it looks. Traditional construction methods fail to be useful on the harsh surface. The moon’s soil clings to everything and binds moving parts (not even WD-40 can fix that). The temperature variances weaken structures. This paper is an index and summary of the top papers in lunar construction. 

Key/Interesting Quotes

“On the lunar surface, numerous constraints,different from those for terrestrial structures, must be satisfied by all designs.” Page 1

“A post-Apollo evaluation of the need for a lunar base has been made (Lowman 1985) with the following reasons given for such a base: Advancing lunar science and astronomy; Stimulus to space technology and test bed for technologies required to place humans on Mars and beyond; Utilization of lunar resources; Establishment of U.S. presence; Stimulation of interest of young Americans in science and engineering; and Beginning of long-range program to ensure survival of species.” Page 1

“Scientific advantages of a polar location for a lunar base (Burke 1985) are that half the sky is continuously visible for astronomy from each pole and that cryogenic instruments can readily be operated there due to the fact that there are shaded regions in perpetual darkness.” Page 2

“Relationships between severe lunar temperature cycles and structural and material fatigue, a problem for exposed structures [need to be studied]” Page 2

“Factors of safety, originally developed to account for uncertainties in the Earth design and construction process, undoubtedly need adjustment for the lunar environment, either up or down, depending on one’s perspective and tolerance for risk [need to be studied]” Page 2

“Buckling, stiffening, and bracing requirements for lunar structures, which will be internally pressurized [need to be studied” Page 2

“…it appears that concurrent engineering will be a byword for lunar structural analysis, design, and erection. Concurrent engineering simultaneously considers system design, manufacturing, and construction, moving major items in the cycle to as early a stage as possible in order to anticipate potential problems. Here, another dimension is added to this definition. Given the extreme nature of the environment contemplated for the structure, concurrency must imply flexibility of design and construction.” Page 2

“…mass rather than weight-based criteria should be the approach of lunar structural engineers.” Page 2

“Newer work and development of nonlinear stress-strain models to describe the mechanics of the lunar regolith can be found in Johnson et al. (1995) and Johnson and Chua (1993)” Page 3

“In the likely situation that a layer of regolith (lunar soil) is placed atop the structure for shielding, the added weight would partially (in the range of 10–20%) balance the forces on the structure caused by internal pressurization” Page 3

“…during the times of low solar activity, the annual dose-equivalent for humans on the exposed lunar surface may be about 30 rem…” Page 3

“…the dose equivalent over an 11 year solar cycle is about 1,000 rem…” Page 3

“…It appears that at least 2.5 m of regolith cover would be required to keep the annual dose of radiation at 5 rem, which is the allowable level for radiation workers…” Page 3

“Construction in a vacuum has several problems. One would be the possibility of outgassing of oil, vapors, and lubricants from pneumatic systems.” Page 3

“The lunar surface has a layer of fine particles that are easily disturbed and placed into suspension. These particles cling to all surfaces” Page 3

“a device that is simple and conventional looking and has no moving parts is preferred [to those which are complex and have many moving parts in space]” Page 4

“Inflatable structural concepts for a lunar base are proposed (Broad 1989) as a means to simplify and speed up the process while lessening the costs.” Page 4-5

“A concept proposed by King et al. (1989) would use the liquid oxygen tank portions of the Space Shuttle external tank assembly for a basic lunar habitat…this idea, if proven economically feasible, may provide the most politically palatable path to the lunar surface, with the added advantage that many of the necessary technologies already exist and only need resurrection” (Page 5)

“Horiguchi et al. (1998) study simulated lunar cement.” Page 5

“In order to avoid the difficulties of mixing concrete on the lunar surface due to lack of water, Gracia and Casanova (1998)have suggested examining use of sulfur concrete because sulfur is readily available on the Moon.” Page 5

“Construction of a lunar base will at least partially rest on the capabilities of the Army Corps of Engineers.” Page 6

“‘In all human societies, the quality of life depends first on the physical infrastructure that provides the basic necessities such as shelter, water, waste disposal, and transportation,’ wrote Grigg (1988) Today, and especially for the lunar base, we have to add communication and power as part of the physical infrastructure.” Page 7

“…the regolith reaches the relative density of 90–100% below 30 cm.” Page 7

“Although the ejection of regolith would not be acceptable on the lunar surface, since the resulting dust would travel far, research showed that explosives buried deep enough would not create craters but loosen the soil very effectively.” Page 7

“Bernold (1994) showed that the compaction of lunar soil necessary for creating a stable road base would create unique problems. Preliminary research data indicated that the normal size distribution of soil particles would make it impossible to achieve needed density and strength using common methods of static or vibratory compaction.” Page 8

‘‘Lunar tramway systems can take advantage of the reduced gravity, which permits building wider spans and/or using smaller cable diameter for lifting and transporting heavy loads.” Page 8

“One of the main problems in robotic control of equipment is the time that signals need to travel through vacuum, atmosphere, or fiber-optic or other communication lines.” Page 9

Personal Response to the Paper

The idea that regolith has a density of 90%-100% below 30cm (about 11.8 inches) stunned me. A lot of the moon base ideas assume that we can build underground, I don’t think we can get through bedrock. On Earth, we blast, but this paper proves that is impractical because the debris produced would orbit the plant, at a low altitude, making the process dangerous. The paper mentions using a wire to loosen the soil, but it is still a difficult process.

It was strange though, I felt encouraged by readying this article despite its presentation of countless problems. It seems that every problem was addressed and those which still need work are neatly listed in an appendix at the back of the paper. This paper provides humanity with a checklist of topics that need to be covered before we can begin lunar settlement. Maybe I feel good about reading this article because it seems a massive task is broken down now. 

Questions Raised by the Paper

What was the process that made the moon’s soil so dense?

The wire on a tramway placed on the moon could produce electricity because of the radiation, could this be a danger to occupants?

The article mentioned most excavation tools wouldn’t work in reduced gravity, I understand most of them, but why wouldn’t a backhoe work?

Assuming we could mix concrete on the moon, what happens to concrete that is outgassed?

What does the Army Corps of Engineers have to do with the moon base and can we use their budget in building it since the article states they will lead the effort?

SPC #18: Open Worlds

Welcome to the Sunday Paper Club. Every Sunday, this blog will offer an analysis of a paper on space habitation and other related topics. These are my opinions on a weekly scientific paper; basically I read the paper and write down my thoughts are I read it. They are subject to my perspectives and believes. I am open to debate, so if any reader believes I have misinterpreted something in a paper, please point it out. I'm only a student and I'm still learning how to read these papers and interpret them. All quotes and ideas are from the paper unless otherwise noted.

This week we are reviewing the paper Lunar Industries and Their Value for the Human Environment on Earth. I am using a new format based on the Lifehacker article Back to School: Keep an Academic Reading Journal.

Article Information

Title: Lunar Industries and Their Value for the Human Environment on Earth

Author: Krafft A. Ehrick

Date: August 1973

Journal: Acta Astronautica

Volume: 1

Issue: 5-6

Article Overview

Currently, humanity operates in a closed world system. We only extract resource from earth; we do not interact with another planetary body in a measurable way. However, an open world existence will give humanity to opportunity to grow endlessly, without damage to the biosphere. This is accomplished through the industrialization of space. Thus, the moon becomes critical because it sets the tone on how we use space. This paper shows use how we can exploit the moon in a profitable way and a path way to becoming a truly space faring species. 

Key/Interesting Quotes

“the information oriented and information controlled interaction with the lunar environment on the basis of synergistically integrating three aspects: extraction of lunar materials for local autonomy, cycling, and utilization of the "waste products" for industrial "export products", in order to supply orbiting installations and lay the foundations for the gradual evolution of a functionally integrated lunar and orbital industrial complex whose ultimate purpose is to reduce the ecological burden on the terrestrial environment, thus improving the human environment without reducing the level of productivity required by modern civilization.” Page 1

“We will never be able to develop or reach another inhabitable world unless we solve first the present crisis [population growth] on this one.” Page 1

“Open space is in many respects a more benign environment than the Earth's surface, to say nothing of the underwater environment”, in industrial applications Page 2

“…we do not live in a closed, isolated world—a ‘spaceship Earth’--but in an open world, on a planet that can be the future cockpit of the solar system.” Page 2

“…long-range thinking in the industrial world should raise its sights to an open-world development program whose central premise is the operative indivisibility of Earth and space” Page 3

“Openworld development means the upgrading of low living standards without destroying existing high living standards.” Page 3

“The central aspect of the extraterrestrial industrial expansion is the acquisition of new environments…” Page 7

“…the industrialization of the Moon will be crucial for the extraterrestrial industrial expansion” Page 7

“The open-world development concept places lunar operations into a new perspective by recognizing the lunar industrial potential and its value for the human environment on Earth. This philosophy adds the spirit of the industrialist to that of the explorer and scientist.” Page 8

“We must further think in terms of lunar production figures of thousands to hundred thousands of tons annually and of cislunar transporter capacities of several thousand tons, if we want to even begin making sense economically and being relevant to the needs of open-world development.” Page 8

A separate study “found that an investment of $150 billion over 30 years would provide a lunar industrial production and transportation capacity (within geolunar space) of at least one million tons annually of raw materials, semi-finished and finished products.” Page 9

“At the center of the lunar disc at high noon, the subsolar horizontal surface is offered 1.35 kw/m^2” Page 10

“The mare basalts are dark, iron-rich and relatively heavy. The anorthosite is a lightly colored, aluminum-rich, less dense material, a major rock-type of the lunar highlands. The lunar anorthosites are more depleted of potassium, uranium and thorium than the mare basalts.” Page 11

“…the Moon seems to be depleted in volatile elements and enriched in refractory elements [metals with high melting points]” Page 13

“even a shallow underground facility, or one covered with regolith, would be well insulated from the variations in solar heat input.” Page 14

“In the lunar environment we can apply strip mining techniques and expend vast amounts of cheap energy without ‘polluting’ the environment. Because this environment is "dead" there are no cyclic processes to consider.” Page 18

The moon’s purpose in space habitation is “the gradual reduction of the industrial burden on the terrestrial environment, thereby improving the human environment while the human industrial capacity continues to grow.” Page 19

“mining on the Moon does not mean going after a particular metal but rather extracting a large number of metals in proportion to their abundance and partly in proportion to the energy expended.” Page 25

Personal Response to the Paper

A while ago, I read the Hard SF article Can Space Colonization End Overpopulation? and I completely abandoned the argument that space habitation can help overpopulation. However, this paper may have proved that space habitation will aid over population indirectly. Population is limited by the resources available which in turn is limited by the amount of energy available. The moon provides an answer to both of these problems, industries can collect resources needed on Earth with abundant energy though solar and nuclear power.

However, I am not comfortable with one of the assumptions the paper makes. The paper assumes there is a seamless transition between the Earth and the moon. Due to the Earth’s gravity well and atmosphere , I feel this is not true. Lunar goods will need to be protected when they are brought down to Earth. Items from Earth while need powerful rockets. So, this paper is leaning towards a reusable system, which is extremely expensive to implement.

Questions Raised by the Paper

This paper assumes the moon is bone dry, now since NASA has confirmed water on the moon, how does the author’s argument change?

Can we be as carefree as the paper suggests when using resources in space?

Nuclear charges are used as the primary mining explosive in this paper, how do we over come the political obstacles to using nuclear explosives in space?

When do we see the return on the investment on the moon?

SPC #8: ASTEN Report

Welcome to the Sunday Paper Club. Every Sunday, this blog will offer analysis of a paper on space habitation and other related topics. These are my opinions on a weekly scientific paper; basically I read the paper and write down my thoughts are I read it. They are subject to my perspectives and believes. I am open to debate, so if any reader believes I have misinterpreted something in a paper, please point it out. I'm only a student and I'm still learning how to read these papers and interpret them. All quotes are from the paper unless otherwise noted. All papers I review are available for free online.

This week we are reviewing the ASTEN Report, the paper which made a kid from Canada famous.

From the first 2 pages of the report, I was impressed. What this kid did was minimize the human extinction argument and presented it in a way the made his point not something to fear, but something that if we address would bring the improvement of mankind. He also points out the positives of a space habitation by writing about how space habitations will promote space and make it more useful.

The paper's assumptions are fairly solid. The writer has assumed that solar panels and Aerogel will have their manufacturing costs reduced. Also, sustainable public opinion is critical for this to work. This will be a major piece of a society's work and the whole society must stay behind it for a long time.

The report goes through the author's thought pattern for designing this station by showing the reader pro and con lists for each element. He presents a very good argument for smaller space stations, stating increased size would "make the project financially unfeasible".

I don't understand why the author stated that the ability to look across and see the other side of the space station as a negative. It might confuse some people and it also might not allow for the space station's residents to be immersed in the illusion of a Earth like environment. But, I don't think the later is a big deal and people eventually stop being confused in spinning structures. However, the paper does choice to use a cylindrical design, which would disprove an early concept I posted about which was spherical. Basically, cylinders allow for even gravity across all surfaces. This student's idea also allows for the modular design which also caused me to call that earlier post's idea brilliant.

What was interesting was the industrial sections are in the middle of the sphere, while the living areas are on the outside. This allows for micro-gravity to be used in industrial applications and the residents while not have all the bone zapping negative effects of Zero-G. Another design advantage over the idea which I held up as brilliant is the inflatable of this space settlement. Also, any industrial accidents would be contained to the center.

This station uses a algae oxygen recovery system. With such a critical system, a natural processes will reduce the moving parts and thus the failure rate of the system. It truly is brilliant. The station uses Demron to protect it's self from radiation.

In short, this is a very interesting idea and this kid is the next Gerard K. O'Neill. I can't wait to see his doctoral paper.

The ISS might have an Economic affect

I was reading the article ISS: Closing in on completion, in the March 2009 issue of Aerospace America, written by Astronaut Tomas D. Jones and this part of the article caught my eye.

Congress declared the station a national laboratory in 2005, and NASA is actively seeking government and industry customers who want to use the ISS for a wide variety of research and applications. NASA will not charge for utilities and crew time, but experimenters must find their own transportation to the station, a major obstacle for smaller enterprises. Low-cost commercial transportation to [low earth orbit] (from SpaceX, Orbital Sciences and others) may offer relief.

By doing this, NASA and the US government is opening the door for any company to get involved in space. Yes, launching to space is expensive, but building a space lab is even more expensive and a well thought out plan should attract enough investors to fund prototype transportation. So, the ISS might be the proving ground for space industry as industrial methods are developed on the station. This could lead to a boom in the space industry as well as manufacturing in general as new materials and techniques as created.

Also, I strongly believe that space-based manufacturing will be the center piece to any space habitation efforts. By providing a incubator for space industry, the ISS could lead to space habitation. A mass scale space habitation effort, just like any other macro-engineering project, would be a huge boost to the economy.

Well, those are my thoughts, what does this quote mean for you?