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System Modeling edit

NOTE: General discussion of system modeling is being moved to section 4.2

Modeling Approach edit

The model consists of functions, and flows that connect the functions to each other and to external inputs and outputs. Each function outputs certain flows, and requires incoming flows to produce the outputs. By convention, the incoming required flows are divided into constraints, inputs, and mechanisms. Constraints control how the function will perform it's task. Inputs are transformed into outputs by the function. Mechanisms are the elements which perform the transformation, but are not themselves changed. As an example, to make a metal part, a computer drawing might be the constraint, a block of metal and electrical power would be the inputs, a computer-controlled 3-axis milling machine the mechanism, and the finished part and metal shavings the outputs.

Drawings - In drawing form, the convention is to show functions as boxes and flows as arrows, with constraints, inputs, and mechanisms coming in from the top, left, and bottom respectively, and outputs going out to the right. Flows can combine and split, as long as the totals before and after match. Drawings are helpful to visualize the interactions in the system, but by themselves do not provide a design solution.

Spreadsheets - In spreadsheet form, we adopt the convention that a function box and the flows entering and leaving it are listed together as rows. Where design alternatives exist, they are additional rows, with a percentage use factor applied. This can range from 0 to 100% for a given alternative, allowing varying mixes. Columns represent different types of resources making up a flow. In our previous example, kg of raw metal and kWh of electricity would be resources. Consumption of a resource gets a negative value, and supply of it is a positive value. Eventually all columns must add to zero, meaning every resource used needs a supply from somewhere. The model is then "balanced" in the accounting sense. We generally work backwards from desired outputs to find what the required inputs are, starting with the allocated requirements. Since the production function supplies outputs to all three functions, including itself, we will start by finding the resource needs of the habitation and transport functions first. This will help determine the required production outputs. By varying the formulas for alternative designs we help determine which are preferred.

A recent version of the spreadsheet developed in this study can be found in the Desktop Space Program on Sourceforge, because Wikibooks cannot store spreadsheet files. The generic template for such models is named Input-Output Model, and one adapted from that template for this study is named Temperate Location Model + a version date. The files are in Microsoft Excel 2010 format. The information to build the spreadsheet will be developed gradually, so it will be incomplete, even past the completion of this study. In a concept level study such as this, not every possibility can be considered, nor every numerical value determined exactly. Rather, the current version of the model represents the current state of knowledge of the design.

Time and Sequence - Building a location and adding production elements involves the time dimension, while a given spreadsheet tends to show the interactions at a particular time. To add the time dimension to the model, one approach is to use multiple sheets within a file, or multiple spreadsheet files to represent different times. This may prove unwieldy, and other software would be a better approach. The options include construction and manufacturing planning software, simulation and analysis software, or custom software. We leave that choice for later if it proves necessary.

Optimization and Selection - After sufficient details are included in the model, a process of optimizing and selecting among alternatives can start by manipulating values within the model. Our method is based on how well a given option meets the evaluation criteria over time. One that leads to a higher integrated score x time function or reaches the desired score faster is preferred. Since we cannot exactly predict the performance of technology that is not yet developed, there will be uncertainty in the resulting scoring. If choices overlap in score when uncertainty is included, we retain multiple options, and identify technology to develop further to reduce the uncertainty. Technologies can also be ranked by how much potential gain in scoring they offer, and thus which ones to work on first. Outside technology development will happen in parallel with a program such as this, and we do not know the results of our own development until it is done. Thus any choices made are subject to revision, and the system modeling process should continue or be updated at intervals.

Habitation Modeling edit

F. Provide Habitation Capacity - Here we will discuss general items for the Habitation function:

  • Requirement 2.3 Self Production - has a distributed requirement to generate 12.75% of the economic value of the location from this function. We will assume this will be a combination of hospitality (hotel and restaurant type), tenancy for owners and leased space, and local work that does not involve the production function (office and business). These will require physical space and resources, which will get distributed to the lower level functions. The owner-occupied portion of space counts for economic value, but does not mean funds change hands, as there is no reason to pay one's self.
  • Requirement 2.4 Quality of Life - sets a goal of $400,000/person of habitation value. This is obtained from equivalent GDP/person ($156,000) x average US property value to income ratio (2.6:1). This will be distributed among the sub-functions as constraints, and an output from F. Assemble Elements.
  • Requirement 4.1 Development Cost - sets a goal for habitation of 20% x $890,000/person x 75 people = $13.35 million for one time development, net of sales. Development expenses are a money output from the location, and the expense distribution becomes a constraint to the sub-elements. Development funding and early sales during development are an input to the location. We assume that location growth is accounted for by replication of items developed for the first 75 people.
  • Requirement 4.2 Location Cost - sets a goal for habitation of 40% x $76,000/person x 75 people = $2.28 million for recurring net cost of the location. This only counts outside costs, not internal production which should supply the bulk of the finished value. It includes raw land cost.
  • Requirement 5.1 Technical risk - sets a goal of performance and design uncertainties of 7.5%. We assign this to F.1.4 Prototype systems to be part of the Risk Analysis report as a data output.
  • Requirement 6.1 Location risk - sets an internal life and casualty risk goal of 38% of US average from Habitation, which is an aggressive target. We assign this to F.1.4 Prototype systems to also be part of the Risk Analysis report. Approaches to meeting this would include better fire safety and higher structural strength.

F. Protect from External Environment - This includes passive protection from weather, water and insects, and structural support of all the Habitation elements.

  • Requirement 1.2 Habitation Scale - Since the land on which it rests or is built into is part of the structural support, we assign land as an input to this function. From the allocated requirement we need 1,000 m2 (0.247 acres) per person or 75,000 m2 (18.53 acres) per year, up to 660,000 m2 (163 acres). This includes land for private living space, community areas like playgrounds and parks, and connecting transportation routes. It does not include land for production functions which also need significant amounts, although they can be overlapped. For example fruit and nut trees can provide some food and also be decorative, and some smaller scale production can be done in private living space. To be conservative, we will assume all production will need its own land allocation. Thus we make the model input I.1 to be "Supply raw land for habitation" and base the formula on the number of people.
  • Requirement 7.1 Biosphere Security - The goal is to help preserve Earth species outside their natural environments against human encroachment or environmental change. This is a service to civilization as a whole. The target is 50% x 89 species either living or stored (seeds or genetic stock/embryos). The remaining 50% is provided by the production function. This can be met with botanical and zoological facilities, greenhouses and pets.

F2. Control Internal Environment - This includes control inputs and sensors (i.e. thermostats) and the active hardware to effect the desired changes (i.e. HVAC systems). Passive insulation is included under the previous function. Lighting and windows are part of the active systems to the extent they can be operable.

  • Requirement 2.3 Autonomy - This has a goal of controlling 85% of habitation functions internally. We assign it to this function. Likely we can reach 100% via a combination of human and automatic devices like thermostats.

F. Provide Food and Drink - Includes the food itself, and provisions for local storage, preparation, serving, and disposal. A portion of the food may be grown in the habitation area (gardens or attached greenhouses), but the majority is expected to come from Production, or outside sources, which become inputs to this function. Potable water supply is part of this function. Food preparation waste and cleanup are outputs. Mechanisms can include standard kitchen equipment, and automated/central food systems.

  • Requirement 2.3 Automation - From this requirement we want to reduce human labor by 85%. In the food and drink area, this could be by automated kitchen. To decrease repetitive hardware, we will assume a centralized automated kitchen with a household delivery system. Individual kitchens will still be available for people who enjoy cooking.

F. Maintain Health - This function includes the basic tasks of sleep, sanitation, and exercise to maintain human health. We will place "Supply residents" as an input, meaning deliver the humans themselves, not supply them with goods, and a percentage of the humans as a labor output. We will ignore births, deaths, and household moves for this initial modeling, although obviously those will matter at some point.

  • Requirement 2.3 Cyclic Flows - We identify a waste output from the location as a whole of 15% or less of mass, and an output from this function and Provide Food and Drink to Production of recycled water and solids.

F. Provide Personal Items - This includes personal living and storage space, and community space. The scale of living space then imposes an input for materials and energy to build and operate the space onto the Assemble Elements and Provide Power functions under Production, and completed Habitation elements as an output of Assemble Elements.

  • Requirement 1.2 Habitation Scale - The program level requirement of Program Scale in terms of number of people to be supported has been partly assigned to Habitation, then further divided into land and living space requirements. We assume 200 m2 of total living space per person. This is derived from a high quality of life goal, and US averages for living space projected to our higher equivalent GDP goal. We further divide this into 160 m2 of private space and 40 m2 of community space per person. During technology development and site construction, we will assume that 15 m2 x 75 people = 1,125 m2 of the community space is for temporary office and storage use, which gets moved to a more permanent location later.

F. Provide Information - This includes educational, entertainment, and general information. We assume robust bandwidth, storage, and processing, which is shared across the location with other functions.

Transport Modeling edit

F. Provide Transport Capacity - The six sub-functions below exist because different methods might be used to carry out each. It is not required, however, to use different methods, they can be implemented by a shared hardware design if that proves more optimal.

  • Requirement 1.2 Transport Scale - The requirement is to provide all internal and external transport at the location for 75 people. This will be distributed to the lower level functions. It includes transport elements built locally and imported from outside the location.
  • Requirement 2.3 Self Production - The allocated requirement is to generate 10% x 85% = 8.5% of the total economic value of the location from this function. This includes the value of transportation services used for local residents and operations, plus any transport provided to outside users.
  • Requirement 2.3 Cyclic Flows - The requirement is to limit un-recycled mass of transport elements to 15%, excluding fuel. This does not include cargo mass. This may be upgraded to include fuel if it can be generated in production, but otherwise is only maintenance items and worn out vehicles. Generates a function for vehicle maintenance in production/assembly.
  • Requirement 2.3 Automation - The goal is to reduce human labor from transport by 85%. This will be applied to the lower level functions, especially to internal transport. It will required automated transport for basic tasks like mowing, trash, and food delivery.
  • Requirement 2.3 Autonomy - The goal is to control 85% of transport locally. This includes manual human control of plus automated control.
  • Requirement 4.1 Development Cost - This sets a goal for transport of 20% x $890,000/person x 75 people = $13.35 million for one time development, net of sales. This becomes a money output from the location, and requires corresponding sources of funding as inputs.
  • Requirement 4.2 Location Cost - sets a goal for transport of 20% x $76,000/person x 75 people = $1.14 million for recurring cost of the location. This only counts outside costs, not internal production which should supply the bulk of the finished value.
  • Requirement 5.1 Technical risk - sets a goal of performance and design uncertainties for transport of 7.5%. We assign this to F.1.4 Prototype systems to be part of the Risk Analysis report as a data output.
  • Requirement 6.1 Location risk - sets an internal life and casualty risk goal of 38% of US average for transport, which is an aggressive target. We assign this to F.1.4 Prototype systems to also be part of the Risk Analysis report. Two ways this might be reached is removing people from the vehicles (automation) and lowering speeds.
  • Requirement 6.2 Population risk - sets a goal of 25% x 17% reduction of population risks for nearest 3.5 million people. This will be a difficult goal to reach.

F. Transport Bulk Cargo - For initial construction of the location, we make an estimate for the Habitation elements of 1 ton/m2 of floor area, based primarily of concrete and wood and other standard building materials, with an average delivery distance of 30 km. Therefore we need 200 tons/person x 75 people x 30 km = 450,000 ton-km. The Production elements are To Be Determined (TBD). Post-construction we will estimate 3% of initial construction per year for maintenance and modifications, so 13,500 ton-km. Bulk cargo does not need special protection during transport, equivalent to an open truck bed. The estimates will likely need to be revised when better data is available.

F. Transport Discrete Cargo - This includes individual items that need protection from the environment, transport shocks and vibration of delivery, or need special packaging. Discrete cargo is typically smaller size than bulk cargo, thus multiple items may be delivered at once. It includes items like furniture, electronics, hazardous chemicals, and food, which need some level of protection during delivery. For furniture and electronics we will estimate 200 kg/m2 initially + 3% per year. Food we estimate at 500 kg/person/year. Hazardous materials are TBD. Again, these will likely need to be revised.

For internal transport of both bulk and discrete cargo within a location we assume a mixture of mobile transport (vehicles) and fixed transport (pipes and conveyor systems). Overhead, underground, and rail systems should be considered to reduce land impact. Amount required is TBD.

F. Transport Humans - Because much of the work and supply of needs for the residents will be at the location, we will make a first guess that 50% of US average driver miles of 21,700 km (13,500 miles) will be required for all purposes. Requires passenger vehicles as a mechanism.

F. Transport Energy - This includes wired and wireless distribution of electricity, and portable sources like batteries and stored thermal energy.

F. Transport Fluids and Gases - These items require closed containers or fixed piping for delivery. It includes water, natural gas, and liquid fuels.

F. Transport Data - This includes all types of data in all forms, electronic and non-electronic. Legal rights and money are delivered via data so they are included here.

Production Modeling edit

Consideration of Habitation and Transport has given some idea of the required scale of Production, to which we now can add production needs for itself, and surplus output goals.

F. Provide Production Capacity -

  • Requirement 1.2 Production Scale - Sets a goal to produce finished elements for Production (itself), Habitation, and Transport for 75 people per year to 660 people total. The Production task is then to make this amount less complete elements supplied from outside, which is nominally 15% on an ongoing basis. The starter set of devices (Seed factory) and initial attachments, bits, tooling, and conventional small shop tools are 100% supplied from outside. During ramp-up to full production a decreasing percentage is supplied from outside. This requirement is distributed to all the lower level functions.
  • Requirement 2.2 Growth - Sets a goal of growing capacity by 11% per year compounded. This is in addition to producing finished elements for 75 people per year and for ongoing maintenance and modification required at 4%/year of completed elements.
  • Requirement 2.3 Self Production - Sets a goal of producing 75% x 85% = 63.75% of the total economic value of the location from Production. The remainder is accounted for by the Habitation and Transport functions, and 15% by residents working outside the location. During ramp up from the starter set, the portion from outside work would be higher.
  • Requirement 2.3 Complexity - Sets a goal of at most 7 major production devices in the starter set (Seed Factory), not counting items listed in 1.2 above. During ramp-up to full production level, as many devices as needed can be added, using a mix of self-produced and outside elements to reach the production goals. Starter set items should be as flexible as possible to cover a wide range of outputs. Later additions can be more dedicated and specialized.
  • Requirement 2.4 Quality of Life - Generate 63.75% x $156,000 = $100,000/person output value of production, counting internally used items, and outside sales of products. 2.3 Self-production requirement above defined the percentage splits among major functions. This requirement sets the value of the output. Production + Habitation + Transport + Outside work should sum to $156,000 value.
  • Requirement 2.6 Resources - This sets a long term goal of producing 10.5 times internal needs for materials and energy, or a surplus of 9.5 times. Initially this goal is distributed to all the lower functions, but it will likely be in uneven amounts after full analysis. After initial construction, we will assume 3% of structures and 5% of vehicles and equipment which are fully used will need maintenance or modification. With a blended rate of 4%, then we make a first estimate of total production capacity at 42% of location materials/year to reach the desired surplus.
  • Requirement 4.1 Development Cost - Production is expected to be the most complicated part of the location design. Thus the goal is set to 60% of total temperate location development cost x $890,000/person x 75 people = $40 million. Since this is a temperate location, no increase for difficult location is used.
  • Requirement 4.2 Location Cost - The goal after ramp-up is 40% x $76,000 x 75 people = $2.28 million recurring cost for production. Initial ramp-up for first 75 people will have less internal production, so we tentatively use an average of 42.5%, and thus (57.5%/15%) x $2.28 million = $8.75 million location cost for first increment.
  • Requirement 5.1 Technical risk - sets a goal of performance and design uncertainties of 7.5%. We assign this to F.1.4 Prototype systems to be part of the Risk Analysis report as a data output.
  • Requirement 6.1 Location Risk - Sets a goal of life and casualty risk from Production of 38% of US average.
  • Requirement 6.2 Population risk - sets a goal of 75% x 17% reduction of population risks for nearest 3.5 million people. Alternately provide a smaller risk reduction to the whole Earth. This will be a difficult goal to reach.
  • Requirement 7.2 Survivability - Sets a goal of 17% compensation for civilization level critical risks x (75 people/150,000 total Phase I) = 0.0085% for this design. Some candidates include contributing to a dedicated asteroid telescope, tree planting in advance of climate zone movement, albedo increase or CO2 removal system to lower climate effects, or improved mining to alleviate resource depletion.

F. Control Location - This provides control of all operational tasks at the location, including habitation and transport. It includes business functions like planning and analysis, real time control, displays, and data collection. It is implemented by a mix of human, automated, and software commands and actions.

  • Requirement 2.3 Automation - The goal is to reduce human labor hours by 85%. This will require extensive control software and linking to other parts of the location to sense status and issue commands. Initial automation levels during growth may be low, but increase over time. This requirement is also distributed to the other functions to actuate commanded actions.
  • Requirement 2.3 Autonomy - The goal is to control 85% of production operations and maintenance locally. During initial growth, higher amounts of outside planning and real time control will likely be needed.

F. Supply Power - This includes supplying electrical, thermal, hydraulic, and other forms of power for all parts of the location. Likely sources are photovoltaic, solar thermal, wind, and possibly organic. There is a goal of producing 10.5 times internal needs.

  • Requirement 2.3 Local Resources - This sets a goal of providing at least 85% of material and energy needs from local resources. Coupled with the goal of a large surplus, we can optimize the output between physical products and energy for best economic value, but with a floor of at least 85% for each.

F. Extract Materials - This includes mining, water and air collection, and harvesting organic products from the temperate location, either from owned or leased land using internal equipment.

  • Requirement 2.3 Local Resources - As noted in the previous item, there is a minimum goal to provide 85% of continuing needs, but a large surplus either in direct materials or more finished products is desired.

F. Process Materials - This includes the conversion of raw materials to finished material inventory. It is expected that a wide variety of chemical, mechanical, thermal, and other processes will be used. The volume is dictated by later production steps and the desire for surplus output.

  • Requirement 2.3 Cyclic Flows - In addition to processing new materials extracted in the previous function, there is a goal of re-processing 85% of waste outputs from the location. Thus other functions need designs which consider what to do with their wastes.

F. Fabricate Parts - This includes transforming ready materials into finished parts by any of a number of processes. The particular processes and quantities will be determined from the needs of the other functions and for itself, plus for meeting surplus production and quality of life goals. This function will need further detailed breakdown. Inputs to fabrication come from outside supply, Process Materials, and Store Inventory. It includes consumable items like cutting bits and cutting fluids. Outputs go to Store Inventory or Assemble Elements for finished parts, and process materials or waste output for scrap and used fluids. In defining the manufactured mechanisms for fabrication, we need to select a starter set by flexibility and largest needs in volume and value, then sequentially add to it in expansion sets. Mechanisms for fabrication within each set can be divided into categories by type, including:

  • Major fixed devices and machines such as 3-axis computer controlled machine tools.
  • Secondary fixed devices such as for measuring and sharpening.
  • Device attachments like mounting plates and rotation tables.
  • Fixtures like custom supports for odd shapes.
  • Portable hand tools, power tools, and measuring instruments.

F. Store Inventory - This function provides storage for materials, parts, and completed items not currently in use, and additionally environment protection and control for other parts of production. The total amount of storage is determined by the needs for assembly, maintenance, and production plans, and any seasonal or batch needs. Storage can be divided into classes by environment needs, ranging from outdoors (no protection), sheltered (water protection only), enclosed, and conditioned (temperature/humidity). It can also be divided into classes by load/area, and items sizes. Items like chemicals will need special storage provisions for safety and physical compatibility. Since storage already needs to provide various levels of environment control and load capacity, we allocate the needs from the other production functions to get total land and building areas.

Inputs to storage will be from Extract Materials, Process Materials, Fabricate Parts, and Outside Supply. Outputs from Storage will be to Process Materials, Fabricate Parts, and Assemble Elements. Mechanisms will be human labor, remote controlled and automated elements, robotic elements, and static storage elements like buildings and shelving.

F. Assemble Elements - This includes assembly and construction leading to completed new elements or maintained existing elements. It accepts new parts and materials from internal production, plus those supplied from outside. It also accepts existing elements requiring maintenance or modification. Any needed dis-assembly is included here, since often that uses the same tools as assembly. Used parts are returned to parts fabrication if they can be reworked, to process material as scrap, or output as program waste. The mechanisms to perform the assembly function can include human labor, robots, automated processes, and specialized assembly equipment and tools. The scale of the assembly task includes:

  • Sufficient new habitation, transport, and production elements for 75 more people per year, less 15% items supplied from outside.
  • Sufficient new production elements for 11%/year growth in production compounded.
  • Sufficient production output to meet the assigned portion of the surplus resources goal, or, to meet the quality of life level, whichever is more.
  • Sufficient production for maintenance and modification of existing items, at an assumed level of 4% of existing location elements.

F. Grow Organics - This includes growing microorganisms, plants, and animals to the point of harvest, after which it goes to process materials or storage. It includes traditional outdoor farming, greenhouses, and indoor facilities. Principal outputs are likely to be food for residents, wood for production, and possibly fuel. In addition will be an allocated part of surplus output.

  • Requirement 7.1 Biosphere Security - This is the remainder of preserving species along with Habitation. The allocated target is 50% x 89 species either living or stored (seeds or genetic stock/embryos). Likely this will be met with greenhouses or biological storage.

For land requirements, we can assume 50% of calories from garden/greenhouse space, at 350 m2/person, and 50% of calories from field crops at 500 m2/person, thus a total of 425 m2/person, or 32,000 m2 total. For supplying a goal of 85% of resident food, we will assume meat and dairy are obtained from outside. Southern mixed forest productivity under good management is 1.5 kg/m2/yr = 1.5 mm thickness of green wood. We need 9 mm of wood/year for maintenance and modification of buildings, therefore we need 6 times the buildings area in forests. For the habitation part only this comes to 1200 x 75 = 90,000 m2 total, and is thus the dominant land area. We will not count any lumber cut from the habitation land itself, and consider that as surplus or bonus. A larger amount of wood is needed for initial construction, which we assume will come from well-stocked timber land which is thinned in the process of building on it, and maintained thereafter. If additional wood is required for initial construction, it is obtained from outside.

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