Space Transport and Engineering Methods/Combined Systems5

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Functional Analysis
In a conceptual design such as this we want to establish one or more program concepts. The concepts describe in a general way how the program will operate. Then we begin a process of breaking down this general description into more detailed steps called Functions. Functions generally transform a set of inputs into a set of outputs. These inputs and outputs are called Flows, and may include any kind of entity: humans, data, hardware, energy. Functions do not define how the transformations happen, just that they occur. The how is embodied in a design solution or alternative, which will come later.

Human civilization already exists, and is expanding in measures of population, energy use, and GDP. There are already space programs that also exist. So the first program concept, which we will call the Existing Baseline is to simply continue current activities without adding anything new. Any other program concepts will need to score better than the baseline to justify going forward with them. We described an initial program concept based on a particular design approach on page 2. To do a thorough job, we should examine other design approaches to see if they lead to promising concepts. Given that a single author is contributing this section at present, this will need to be limited in scope to examining approaches already proposed by others. There is an opportunity here for other individuals or teams to add to this work with additional approaches and concepts. The important thing is to compare alternatives on a fair basis, using similar goals, evaluation criteria, technology levels, and cost estimating methods.

Current Parameter Status
Some of our criteria for comparing programs are scored relative to features of existing civilization, so as a starting point we will identify the current status of these parameters. The initial version of this functional analysis is being written in late 2012, so we will use the start of 2013 as "current". If the entire conceptual design process takes a long time, the information should be updated to a new current date. 2015 is suggested for the next update.

Environment Ranges
The Temperate range is defined as where 90% of people currently live, and more difficult and extreme environments are respectively > 10% and 20% beyond that. Analysis of where people live vs environment conditions is being developed separately in the Sec 5.2 - Environment Ranges Design Study. This is being done in two steps due to the mass of detail in mapping out where people live. The following table lists initial estimates for the boundaries of the Temperate range, and the inner boundary values for the difficult and extreme ranges. When the second part of the Environment Range study is complete, these will be updated.

add: Physical resources and environmental toxins

Existing Baseline Program
Our existing baseline can be defined by looking at world development trends and existing space programs to the point that uncertainties in items like GDP or new technology are larger than 50% of our estimates. At that point the future is too uncertain to project reasonably, therefore we stop. Future updates to this kind of conceptual design study, done in 5 or 10 years time, can then project forward to a new uncertainty horizon. Other program concepts will also have a time horizon bounded by uncertainties, and should explicitly identify what those limits are. In examining world development and existing space programs, we do not need to examine their every detail, but only the parts that affect the scoring in the evaluation criteria we have chosen.

Evaluation Score
We take our previous table of evaluation criteria, and apply them to the current baseline:

New Program Concept
Our new program concept was first stated in a general way on page 2. The basic approach was to enable expansion by developing advanced technologies, then build a series of new locations in more difficult environments, and within each location increase in size and technical performance. The obvious functional breakdown is then first by level of technology, which defines what is possible to build, then the locations, defined by a set of environment conditions. As better technology becomes available, the locations are upgraded to targeted size and performance levels. A "location" is a general environment, such as tropical ocean or Low Earth Orbit. Selection of specific sites is left to later. To determine how many phases of upgrades are needed, we will optimize based on what can be reached in a first phase, and what size steps are reasonable. As a goal, we think a phase should provide at least a 10 point increase in evaluation score, to be significant enough to implement.

The primary functions within a location include production, habitation, and transport capacities. These allow it to support people at the location, and interact with the rest of civilization. We will develop functional flow diagrams to model these elements and the flows that connect them to each other and outside the program.

Expansion Phases
Our partial evaluation score for existing civilization is about 75 points, so we will attempt to formulate a location concept that yields a total score of 85 for Phase I. Later will will adjust and optimize this concept. For now we just want a single example to start with. Later phases will try to increase in steps of 10 to 105 points in Phase III. We don't expect to be able to plan beyond Phase III at this early date, since implementing that far in the future involves too much uncertainty.

Develop Technology (Phase 0)
Before we implement the first phase, we have to develop sufficient technology to reach the desired program goals for that phase. This includes doing conceptual and preliminary design, developing new technologies, and building prototype systems to demonstrate performance. This preliminary phase we will call Phase 0. Assuming this phase shows enough gains over the current baseline, we then proceed to the next phase.

Conceptual Design

Preliminary Design

New Technologies

It is not necessary to duplicate work for technologies which already have large efforts in progress. Thus electronics, for example, is not an area we would put much effort into. It is already a major industry with high levels of funding for technology development. Instead we will apply efforts to areas specific to the program, and which are not getting sufficient attention. The selection of which technologies to work on first will depend on ranking their relative potential impact, development difficulty, and timing of the need for it.

As a new technology reaches a sufficient level of improvement, it will migrate from this task to prototyping. If it performs well enough, it will then move to one of the later implementation phases. If more progress appears possible, a given technology goes back into the development cycle, and the amount of effort based again on ranking vs other technologies. Thus Phase 0 does not end once Phase I starts, but continues as long as there is sufficient improvement possible, periodically feeding new improvements to later locations and phases.

Prototype Scaling

It is less expensive to build smaller prototypes to try out new technologies and demonstrate performance, so we will establish a series of mass and linear scales derived from the "full scale" level of supporting 75 people/year. Not everything can be prototyped this way, but it will be used where effective. Habitation is an obvious example where scaling in all dimensions is not feasible, although scaling in area is possible. The scale steps get smaller as size goes up due to increasing cost. Consistent scaling steps helps ensure different items will work together when integrated. Initial sizes of prototypes and which scale steps to use will be determined for each technology. There is an opportunity to sell copies of the smaller scale elements, or do initial production and operations with them, as ways of generating income for further growth.

The scales are as follows:


 * 1/10 Scale - This is 10% linear, or 0.001 mass and volume, or support 0.075 people/year capacity.
 * 1/5 Scale - This is 20% linear, or 0.008 mass and volume, or support 0.60 people/year capacity.
 * 1/3 Scale - This is 1/3 linear, or 0.037 mass and volume, or support 2.75 people/year capacity.
 * 1/2 Scale - This is 50% linear, or 0.125 mass and volume, or support about 9-10 people/year capacity.
 * 3/4 Scale - This is 75% linear, or 0.422 mass and volume, or support about 30 people/year capacity.
 * Full Scale - This is 100% linear, or 1.000 mass and volume, or support 75 people/year capacity.

Later growth may require larger prototypes, and multiple copies of a given size may always be used for more capacity.

An example of scaling is reducing a 36 inch x 21 ft capacity, 30 hp electric commercial sawmill down to 0.5 hp electric (a factor of 60 in power), and reducing log capacity by 2.5 in each axis (a ratio of 15.625 in log volume), giving a total reduction of 937.5, roughly the 0.001 mass and volume scaling for the smallest size. In US terms the log capacity is 15" diameter by 8 ft long or 12" diameter by 12 ft long. The smaller motor is suitable for slower production rates, and the smaller size is suitable for home use. 600 lb log weights can be handled by a single person using leverage at each end singly.

Develop Phase 1 Locations
The following program parameters result by working backwards from an 85% score for each evaluation criterion, or 10% higher than the baseline. They are goals, the actual values will be found at the end of the conceptual design.


 * 1.2 Program scale: Average population/location = 3000, total population = 150,000. Number of locations = 50.  We will assume an inverse size distribution where size for the nth largest location is 1/n times the largest location.  For 50 locations the total is 4.5 times the largest. This comes from Zipf's Law, an empirical observation for city sizes.  This gives a smallest location of 660 and a largest of 33,000.
 * 2.1 Number of Locations: Actual count of locations is 50, giving 50% score. We compensate by increasing range of environments to 240 steps, giving 120% score.
 * 2.2 Growth: 11% per year, giving 9 year time to completion, and 75 people as minimum location design size.
 * 2.3 Improved Technology: 85% direct values for local resources, finished products, recycled fraction, automation, and autonomy.
 * 2.4 Quality of Life: Equivalent GDP (counting internal production) = $156,000 US
 * 2.6 Resources: 10.5 x internal materials and energy over life cycle, or 950% surplus.
 * 4.1 Total Development Cost: Allow 11.7x unit cost on Earth, 1.2x in space. Allows $890,000 development/person for temperate location, +10% per environment step compounded for more difficult locations, and ln(size) for increased size of same environment.
 * 4.2 New Location Cost: Per person = $76,000 Earth, Space = $152,000.
 * 4.3 Earth Launch Cost: $23/kg including space resources factor. Nominal split is $150/kg actual launch cost and 15% non-space resources factor.
 * 5.1 Technical Risk: 7.5% technical uncertainty
 * 6.1 New Location Risk: Allow 38% casualty risk for new locations
 * 6.2 Population Risk: 17% reduction to population risks
 * 7.1 Biosphere Security: 178,000 species x locations maintained outside natural range
 * 7.2 Survivability: 17% compensation for critical risks

Schedule

We assume a notional schedule which ramps up gradually. Assuming a "zeroth" location for prototyping we allow 6.5 years for Phase 0 to develop the technologies, after which the first Earth location starts at a scale of 75 people and grows by 75 per year to 660. Annual population growth increases by 11% per year, so added locations are started when enough margin over first location exists, until all 50 locations are built, nominally ~50 years.

Technology development is assumed to continue for 6.5 more years to initiate Phase II, and 7 more years to initiate Phase III, so later sites will use upgraded technology, and older sites retro-fitted to improved levels. Budget for prototype work is $66 million, resulting in ~36 resident capacity.

Later Phases
At this point it is too early to try and define later phases in much detail, aside from setting evaluation scores of 95 and 105%.

- [Following text saved from Section 4.1:] -

Level 2: Phases
The program phases are defined for now by aiming for a 10 point increase in evaluation score per phase. Early estimates of the existing baseline indicate a score of 20 points, so Phase I would aim for a score of 30, Phase II for 40 points, and Phase III for 50 points. Once the design alternatives are better understood, and what performance is feasible, the number and spacing of phases may be changed later.

Numerical Goals

Phase I
Phase I aims at a 10 point improvement over the existing baseline. The baseline is estimated to score 20 points, thus this phase aims at 30 points. The exact program parameters to reach this score depend on many lower level choices still to be made, and technology still to be proven. We know that this phase will involve some number of Earth and Near Space locations, and some level of improved technology.

Phase II
Phase II would aim at a further 10 point increase in program score. This will likely require more technology development, and because of the time span since the preliminary phase, some redesign and upgrade of Phase I elements will likely be needed.

Phase III
Phase III is currently aimed at a program score of 50 points. Because it is further out in time and difficulty, this phase is left as a more preliminary concept, more to guide the direction of the earlier phases. Unanticipated new technology is likely to affect designs this far in the future. Phases after this one (IV+) are therefore reserved for future design work. - [End saved text] -

Locations List
This list is tentative pending completion of the environment ranges study.


 * Temperate Earth - Our first environment is within the middle 90% range of current civilization. The reason is to first develop improved technology, such as seed factories and cyclic flows, where it is easiest to do the work, and where it will have the widest immediate application.


 * Non-Temperate Earth - This group has one or more parameters outside the Temperate range, but not reaching the Difficult level. They are named by whichever parameter is most out of range.  Many combinations are possible.


 * - Hot Locations - These are where summer daytime highs exceed 310K (37C). Death Valley, California, generally considered the hottest place on Earth, reaches 47C for average summer daily high, so no place on the surface reaches the difficult level of 341K (68C) except for volcanic areas. The TauTona gold mine in South Africa, which reaches 4 km below the Earth's surface, has a rock face temperature of 60C, so it also does not reach the difficult level.


 * - Cold Locations - These are where winter nighttime lows are below 260K (-13C). Vostok Station, Antarctica, is considered the coldest place on Earth, and reaches an average winter low of 201K (-72C). This is below the extreme low threshold of 208K (-65C), so the Earth includes Non-Temperate, Difficult, and Extreme Cold Locations.


 * - High Water Locations - Nominally these are areas that get more than 2.5 meters (100 inches) of rainfall or other fresh water sources, such as river flow, per year. Since the maximum water supply reaches about 10 meters/year, there are about 14 steps above the Temperate range on Earth, in 10% compounded increments. Significant tropical areas fall into the Non-Temperate range from rainfall alone, and some areas near major rivers reach the highest values.


 * - Low Water Locations - Nominally these are areas that get less then 0.25 meters (10 inches) of rainfall or other fresh water sources/year. The driest location on Earth, the Atacama Desert in Chile gets as little as 0.001 meters/year, so there are 10 steps in dryness below the Temperate range, in 0.025 m/yr increments.  Significant parts of the Sahara Desert fall into the lowest step.


 * Difficult Earth Locations - This group of locations push one or more environment parameters more than 10% beyond the temperate range.  Based on our environment parameters, we can start to identify such locations, and then combine ones where multiple parameters can be addressed at once.  All the ranges are based on what the upper and lower 5% of current population live with:


 * Extreme Earth Locations - This group includes as many locations as needed to push environment parameters to the limits of practicality. Some parameters may have no practical use beyond a limiting value even if conditions exist beyond them.


 * Near Earth Space - These start with the lowest useful Earth orbits at about 200 km altitude and extend upwards to 10% beyond Earth escape energy.


 * Distant Space

Functions


Figure 5.1-1 is a very preliminary diagram showing the functional elements and flows for a generic location. Functions must trace back to at least one program goal or requirement, otherwise they are unnecessary. This can be either a direct reference to a source, or an indirect derivation by analysis. For the elements in this diagram at least one source each that justifies their inclusion are:


 * Diagram as a whole - Multiple locations will make up the total program, so the entire diagram is an element in a higher level diagram. The need for locations comes from 1.1 Program Goal - "...a series of new locations...".
 * Provide Production Capacity - comes from 2.3 Improved Technology - "...increase the levels of self production..."
 * Provide Habitation Capacity - comes from 1.2 Program Scale - "...permanently supporting at least 95,000 humans total among new Earth locations and at least 2,000 humans per new space location." The physical support to live in a given location we will call Habitation.
 * Provide Transport Capacity - comes indirectly from 1.1 Program goal "...expand human civilization...". The new locations are not cut off from existing civilization or each other, therefore they need capacity to transport people and supplies in, and products out.  It comes more directly from "...a series of new locations...", since the mere existence of new locations requires transport to set them up.

Flows into and out of the diagram, and between functions can contain any kind of hardware, software, data, or people. Later analysis will define exactly what each flow contains, but they must follow the rule that flows are conserved. This comes from the physical fact that items do not appear from or disappear into nothing. Thus dividing or combining flows must sum to the same totals on both sides, and so must inputs and outputs to a function (although a function may convert the types of flows). Conservation of flows ensures that all inputs and outputs of a system are considered and accounted for. In this preliminary diagram we merely identify some of the major flows.

To continue the functional analysis, we break down the three top-level functions into lower level elements. Partitioning functions into more detailed ones creates logical boundaries inside a larger system. This then identifies flows which cross the internal boundaries, and creates simpler elements to design. The lower level functions should have an internal coherence or relatedness. Since the partitioning is logical, and not physical, it can be done in different ways, and often is to develop alternate designs. A good understanding of the nature of the system is very helpful in developing the lower level functions, which in turn may require specialist knowledge.

As a start, we can create one list of lower level functions drawn from past experience. They will likely strongly interact with each other, with many flows between the sub-functions, so a flow diagram may be too complicated to use. We will consider a table or spreadsheet instead. We also identify categories of inputs to and outputs from the location as a whole. A location is connected physically to its environment, and interacts with other locations and civilization as a whole, so flows crossing the location logical boundary are part of the analysis. The inputs and outputs will then later be divided among the more detailed functions.

Location Inputs

 * Energy Sources
 * Food Sources
 * Water Sources
 * Parts and Materials Supply
 * Tools and Machines Supply
 * Land Inputs
 * Human Inputs
 * Money Inputs
 * Information Inputs

Location Outputs

 * Surplus Energy
 * Surplus Food
 * Surplus Water
 * Surplus Parts and Materials
 * Surplus Tools and Machines
 * Surplus Land
 * Surplus Humans
 * Money Outputs
 * Information Outputs
 * Waste Outputs

Production Functions

 * Control Location
 * Supply Power
 * Extract Materials
 * Process Materials
 * Fabricate Parts
 * Store Inventory
 * Assemble Elements
 * Grow Organics

Habitation Functions

 * Protect From External Environment
 * Control Internal Environment
 * Provide Food
 * Maintain Health
 * Provide Personal Items
 * Provide Information

Transport Functions

 * Deliver Bulk Cargo
 * Deliver Delicate Cargo
 * Deliver Humans

[Parked Content from Section 4.1]

Program Requirements
The initial set of program requirements were developed by carefully looking at the program goals and benefits, general systems engineering experience, and natural and human constraints. We divided the general goals into more specific statements with measurable parameters. We also looked at our ideas for approaching the design, and the first list of elements to be included in the program, to see if they yield any requirements. We combined and formalized the resulting statements to create a first draft of the top level requirements. Some of the numerical values are arbitrary, but we need to set something as a starting point, which can be adjusted later as the design evolves.


 * 1. Objectives


 * 1.1 Program Goal - The program shall expand human civilization to a series of new locations with increasingly difficult environments and distance.
 * 1.2 Program Scale - Expansion shall be demonstrated by permanently supporting at least 95,000 humans total among new Earth locations and at least 2,000 humans per new space location.
 * 1.3 Choice - Specific locations and their internal organization, function, and operation shall be chosen by program participants and location residents within the limits of design constraints.


 * 2. Performance


 * 2.1 Number of Locations - The design shall maximize the number of new locations, where new is defined by at least a 10% increase in an environment parameter or distance measured in time or energy terms.
 * 2.2 Growth - Each location shall increase the capacity for production, habitation, and transport in a progressive manner.
 * 2.3 Improved Technology - Locations shall increase the levels of self-production, cyclic flows, and autonomy in a progressive manner.
 * 2.4 Improved Quality of Life - Completed locations shall provide an improved physical and social quality of life relative to the upper 10% of Earth civilization.
 * 2.5 Data - The program shall collect and disseminate [TBD] data about the Earth's environment, surrounding space, and objects therein.
 * 2.6 Resources - The program shall output a life cycle surplus of at least 100% of internal material and energy resource needs.


 * 3. Schedule


 * 3.1 Completion Time - The expansion to a new location shall be completed before expected progress in technology indicates a re-design is required.


 * 4. Cost


 * 4.1 Total Development Cost - The total program development cost for new technology and hardware designs shall be less than 50 times the unit cost on Earth, and 5 times the unit cost in space of the hardware.
 * 4.2 New Location Cost - The peak net project cost for a new location shall be less than 50% of the expected long term net output.
 * 4.3 Earth Launch Cost - The program shall progressively lower the Earth launch cost component of total system cost, with a goal of $0.08/kg of total system mass.


 * 5. Technical Risk


 * 5.1 Risk Allowances - Program designs shall include allowances for uncertainties and unknowns in knowledge, performance, failure rates, and other technical parameters. New designs with higher risk can be included in program plans, but a process shall be included to resolve the risk, and an alternate design with lower risk maintained until resolved.


 * 6. Safety


 * 6.1 New Location Risk - New locations shall progressively lower internal risks to life and property, with a goal of significantly lower risk than the general population.
 * 6.2 Population Risk - The program shall significantly reduce natural and human-made risks to the general population, including external risks created by the program.


 * 7. Sustainability


 * 7.1 Biosphere Security - The program shall increase biosphere security by establishing alternate biospheres and long term storage of biological materials.
 * 7.2 Survivability - The program shall design for the long term survival of life and humanity from changes to the Earth which will render it uninhabitable and depletion of critical resources.


 * 8. Openness


 * 8.1 Open Design - Technology and design methods developed within the program shall be open for others to use. Specific instances of a design and produced items may be proprietary.
 * 8.2 Access - Development of a new location shall not prevent reasonable access for transit or to unused resources.

Evaluation Criteria
Setting discrete program requirements like the ones listed above are unlikely to be the optimum values, and do not help in choosing among design alternatives. For those purposes we choose parameters to measure our evolving design and guide it to the preferred result. We identify these parameters by again carefully looking at all the work done so far, and selecting the ones most important at the program level. After selection, we then scale and adjust their relative importance to each other so that a score can be determined for each design option or variation. Our resulting criteria and how they are scored is as follows: