2013 Living Systems Theory for Missions to Mars - Companion Paper

7/27/2019 2013 Living Systems Theory for Missions to Mars - Companion Paper

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In this paper we demonstrate that the introduction of Millers Living Systems Theory

categories:

Provides an alternate way to decompose system requirements based on living systemsfunctions, and

Provides a new way to use UML based functional decomposition to model biological

functions.

Living System Theory (LST) oriented functional decompositions are applied in this paper

to a number of space environmental control and life support systems (ECLSS), namely:

In the transportation habitat, or Transhab context,

In a Martian surface habitat, or Surfacehab context,

In an extra-vehicular mobility unit, or EMU spacewalking context, and

In a surface mobility unit or SMU Martian surface exploration suit context.

The Application of Hatley-Pirbhai (HP) Diagrams to LST Categories are also reviewed inthis paper as a way to sort LST categories as input, processing, and output activities for

both Mass-Energy (ME) categories and Information Processing (IP) categories.

Finally, a subset of Millers five flows are examined for their utility in this paper,

including mission directed personnel and information flows in the mission context, as

well as Mass-Energy flows in local contexts, i.e. in the Transhab and Surfacehabcontexts.

1.1 The 20 Categories of Living Systems Theory (LST)

Table 1.1-1 presents the LST categories as they are currently understood. [1,4] Miller had

initially conceived of and introduced a formal symbology set [2] that included a different

symbol for each functional category, so that schematics of living systems might becreated, but such schematics were too obscure to ever find widespread use. Therefore we

introduce a set of 3 letter abbreviations, or trigraphs [3], also shown in table 1.1-1, which

will be used throughout the remainder of this paper to represent these categories in blockdiagrams, schematics, and flowcharts. They are designated with capital letters in square

brackets, as in the example [PRD].

LST functional categories are of these three types: categories that process matter andenergy, categories that process information, and categories that process both matter-

energy and information. One may readily observe the utility of such categories to the

human space flight, as they are useful for mapping the flows of matter, energy, and

information into and out of human living quarters. To some extent we see all of theseprocesses in play with any human occupied systems, but they are especially appropriate

for highly isolated and well defined systems such as a space station or space explorationvehicle. Why use LST categories at all? Utility is derived because a staffed facility is a

living thing, an extended version of a life form, and in that very real sense there is value

in this form of biologically oriented functional analysis, as we will see in the remainderof this paper.


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Table 1.1-1, Living System Theory (LST) Categories [1,4]

1.2 Mass-Energy Handling Categories

In his work Applications of Living Systems Theory to Life in Space [2] James Miller

discussed applying the five flows, or transmissions, in living systems to spaceflight.Those five flows are matter, energy, information, people, and money and are depicted in

the example of the ISS as shown in figure 1.2-1. From an engineering point of view, we

will largely ignore two of these flows: people flow, which is of more interest to

operational planners, and capital flow, or what Miller simply calls money flow. Whilethis is of enormous interest from a financial planning point of view to NASA, sovereign

treasuries, and private funding organizations such as the Mars Initiative, it is beyond the

scope of the present paper.

The flows remaining for detailed engineering study are matter flows, energy flows, and

information flows. Let us first examine matter flows. Matter will enter human occupiedliving spaces via the category of ingestion [ING]. Ingestion may occur in a number of

different ways: from an exterior point of view new assemblies that arrive on orbit are

attached or aggregated via either robotic control [MOT], or via human intervention[PRD] using spacewalks [MOT] to connect new elements to the exterior support structure

[SUP]. The second type of ingestion occurs via an airlock, in the case where matter is

Icon Trigraph Category Name Icon Trigraph Category Name

MATTER-ENERGY LST CATEGORIES

ING Ingestor STR ME Storage

DST Distributor EXT Extruder

CNV Convertor MOT Motor

PRD Producer SUP Supporter

INFO-PROCESSING LST CATEGORIES

INT Input Transducer MEM Memory

ITL Internal Transducer ASC Associator

DCD Decoder DEC Decider

TIM Timer ECD Encoder

NET Network OUT Output Transducer

BOTH M-E AND INFO LST CATEGORIES

BND Boundary REP Reproducer

Icon Trigraph Category Name Icon Trigraph Category Name

MATTER-ENERGY LST CATEGORIES

ING Ingestor STR ME Storage

DST Distributor EXT Extruder

CNV Convertor MOT Motor

PRD Producer SUP Supporter

INFO-PROCESSING LST CATEGORIES

INT Input Transducer MEM Memory

ITL Internal Transducer ASC Associator

DCD Decoder DEC Decider

TIM Timer ECD Encoder

NET Network OUT Output Transducer

BOTH M-E AND INFO LST CATEGORIES

BND Boundary REP Reproducer


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intended to be deployed and distributed [DST] within habitation interior spaces.

Personnel ingress from an EVA would proceed through such an airlock.

Figure 1.2-1, The Application of LST to the ISS [2]

Matter may also be expelled, or in the parlance of LST, extruded [EXT]. Extrusions may

be of any phase of matter, and might range in size from returned experimental apparatusthat is sent out on otherwise empty return trips of supply vessels, to the gaseous release of

waste products from air treatment processes. EVA egress would also fit the [EXT]

category of functionality.

Energy flow may be treated similarly. In this case energy is ingested for instance in the

solar panels, is converted [CNV] to electricity, and is then distributed [DST] to energy

consumers throughout the living quarters in question. Waste heat not converted to useful

work is collected via circulating coolant and is expelled through radiative panels thattransfer energy via thermal photon radiation directly into space as an extrusion [EXT].

Energy may also be stored, [STR] chemically in batteries or in the form of propellant, ormechanically in momentum wheels, and may be applied for motor related activities

[MOT], for instance in attitude control and station keeping.


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1.3 Information Processing Categories

Let us now turn to an analysis of information flow, which is treated by the second group

of LST categories, information categories, of which the author suggests also

simultaneously represents a categorization of communication functions. After all, howdoes information get in and out of an information enclave [BND] other than

communication? Communication represents the onboard and offboard flow ofinformation. Therefore we understand the information categories to include

telecommunications as well, where receivers are understood to represent special cases of

input transducers [INT], and transmitters are understood to represent special cases ofoutput transducers [OUT]. Within the enclave [BND], the onboard information flows

over a network [NET], regulated by a clock or timer [TIM]. Internal housekeeping data

may be added into the data stream via internal transducers [ITL], and for instance analog

data may be ingested into digital via decoders [DCD] or created from digital via encoders[ECD]. Association [ASC] may be preprogrammed in advance via software code, or may

be determined in realtime via a human presence [DEC].

It is worth pausing at this point to recognize the special role the human has in the activity

of human spaceflight. The human is an extension of a productive presence [PRD] in the

domain of matter and energy, and represents a local deciding presence [DEC] in theinformation domain. The human presence is tying together both the mass-energy

dimensions and the information dimensions at the cognitive peak of mass-energy and

information control loops by simultaneously fulfilling both the roles of producer [PRD]

and decider [DEC]. Due to the data bandwidth communicated and then time criticality ofthat data, or control bandwidth, a local presence for the control loops of all of these

dimensions (mass, energy, and data) is the main contribution of a human presence in

space exploration, and is an additional rationale for the inclusion of the local in situhuman element in spaceflight activities. This area could benefit from further study by

quantifying the impact of [PRD] and [DEC] roles on needed control loops in HSF

mission control areas with and without a local human presence.

1.4 Categories that Process Mass-Energy and Information

Finally we discuss the last two LST categories, those that process both matter-energy andinformation. The first of these is the boundary [BND], the dividing line that separates any

systems interior from its exterior. This is important from a matter-energy point of view

in that it delineates and defines what constitutes system structures and energy contentfrom external structures and energy sources. From an information point of view it divides

the information that resides within the system from the information not contained by (or

known by) the system in question. The second and final category that processes mass,energy, and information is reproduction [REP]. For a system to reproduce itself in must

reproduce not only a subset of the mass and energy it contains, but also a critical subset

of the information it contains, that subset required to perpetuate life.


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2. LST CONTEXT DIAGRAMS FOR MISSIONS TO MARS

2.1 Problem Statement

How can LST categories help with requirements development? Like any other functional

decomposition LST categories serve as a useful inventory of possible needs of a given

system. In the case of LST, the typical design patterns associated with supporting andsustaining life will give rise to needs or requirements in nearly all of these categories.

The first step in revealing requirements through functional decomposition is to define the

context in which the system will operate, which in turn helps to reveal the system itself.

For the case of missions to Mars, four contexts are examined: a deep space Transhabcontext in section 2.2, a Mars Surfacehab context in section 2.3, a deep space EMU

spacewalking context in section 2.4.1, and a Martian surface SMU exploration suit

context in section 2.4.2.

2.2 Transhab LST Context

In this section we develop the Transhab context, summarized in figure 2.2-1.

Figure 2.2-1, Transhab LST Context Diagram

We first note that there is the context of the Transhab itself in relation to both sunlit and

shaded space. Within the Transhab is the crew, which may collectively be taken togetherin relation to the Transhab. There is therefore in figure 2.2-1 two nested context

diagrams, one for the Transhab in space, and one for the crew in the Transhab.

Taking the outer context first, aside from crew ingress (not shown) there is very little

mass-energy input into the Transhab. Only solar energy is ingested [ING]. In the

Sunlit Space

Crew

Transhab

Shaded Space

SolarEnergy

Info:Com,Nav,Time,

Sensors

Info:Com,Nav,

Status

O2

H2O

Food

CO2

H2Ovaporwaste

Info:C3I

RadiativeCooling

Ventedwaste

Solidwaste

Info:C3I,CSS

C3I = Commed Cmd, Control, and IntelCSS = Commed Sensors & Status

Sunlit Space

Crew

Transhab

Shaded Space

SolarEnergy

Info:Com,Nav,Time,

Sensors

Info:Com,Nav,

Status

O2

H2O

Food

CO2

H2Ovaporwaste

Info:C3I

RadiativeCooling

Ventedwaste

Solidwaste

Info:C3I,CSS



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information domain communication, navigation, timing, and sensors for situational

awareness (such as cameras) need to be provided [INT].

On the output side, waste heat must be extruded [EXT] or emitted to space, and

command, control, and status information must be communicated to Martian surface

elements and back to Earth as an output [OUT].

Within the Transhab there must be a habitable boundary [BND] and structure [SUP] ofsufficient volume to maintain a living space commensurate with NASA long duration

mission standards [6]. The Transhab must supply the crew with the oxygen, water, and

food needed to sustain life. These inputs are quantified in section 4.2. Likewise the

Transhab must be able to accept waste products from the crew, including CO2, watervapor, and so on, and to the extent possible recycle these products for reuse as life

sustaining inputs, so as to minimize the need for stored provisions [STR].

2.3 Surface LST Context

Sustaining the crew on the surface of Mars is presented in the nested context diagram offigure 2.3-1 for the case of the Surfacehab.

Figure 2.3-1, Surfacehab LST Context Diagram

In dwelling on the differences between the Transhab and Surfacehab cases, we may first

note that there is now a much greater presence of resources, in the form of Martianatmosphere and regolith. These resources may be leveraged to great effect externally to

the Surfacehab in the form of a greenhouse, of potentially lesser atmospheric pressure

and at a reduced temperature, for the ingestion [ING] of organic produce. Likewise both

Martian Atmosphere

Martian Regolith

Surfacehab

Crew

SolarEnergy

Info:

Com, Nav,Time, Sensors

Info:Com,Nav,

Status

O2

H2O

Food

CO2

H2Ovaporwaste

Info:C3I

ConvectiveCooling

Ventedwaste

Solidwaste

Info:C3I,CSS


Atmosphere

GreenhouseFood

RegolithDerived H2O Conductive

Cooling

Martian Atmosphere

Martian Regolith

Surfacehab

Crew

SolarEnergy

Info:


Info:Com,Nav,

Status

O2

H2O

Food

CO2

H2Ovaporwaste

Info:C3I

ConvectiveCooling

Ventedwaste

Solidwaste

Info:C3I,CSS


Atmosphere

GreenhouseFood

RegolithDerived H2O Conductive

Cooling


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atmosphere and potentially regolith may be externally preprocessed to provide many of

the life support resources needed by the Surfacehab such as H2O and O2.

On the mass-energy output side [EXT], the cooling will be simpler: rather than the space

radiators of the Transhab, exploiting the options of conductive cooling to the soil or

convective cooling to the atmosphere will greatly simplify the cooling design associated

with the thermal control of the Surfacehab.

2.4 Spacesuit Context Diagrams

The case of an astronaut in a deep space spacesuit is substantially different from the case

of a Martian surface habitant in a surface exploration suit. Context diagrams for these two

cases are therefore handled separately in sections 2.4.1 and 2.4.2.

2.4.1 EMU for use with Transhab

Figure 2.4.1-1 is the context diagram for an astronaut in an EMU. The EMU itself willneed to provide access for the astronaut, and yet must maintain pressure during the

spacewalk. Visual situational awareness must be provided, either through the use of a

visor and/or the use of cameras small with monitors or eye-projectors, (such as Google-glasses). External lighting will be required for illumination in shaded space, (not shown).

Figure 2.4.1-1, EMU LST Context Diagram

Mechanical manipulation and vectored movement must be provided and must be under

positive control from within the suit via a natural feeling interface, (such as joysticks orrollerballs). All of these functions have been demonstrated for generations by NASA, but

for Mars missions an unprecedented level of reliability and flexibility will be required, as

spares will be at a premium for mission durations that will extend into multiple years.

Sunlit Space

Shaded Space

Astronaut

Extravehicular

Mobility

Unit

Info:Com, Nav,

Time, Sensors

Access

VisualSit

Awareness

A/Vs

O2, H2O

Support,Pressure

Voice

Touch cmdw/ feedback

WasteStorage

Info:C3I

MechanicalManipulation

ThrustVectoring

Sunlit Space

Shaded Space

Astronaut

Extravehicular

Mobility

Unit

Info:Com, Nav,

Time, Sensors

Access

VisualSit

Awareness

A/Vs

O2, H2O

Support,Pressure

Voice

Touch cmdw/ feedback

WasteStorage

Info:C3I

MechanicalManipulation

ThrustVectoring


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2.4.2 SMU for use with Surfacehab

A Surface Mobility Unit (or surface exploration suit) for Mars will be challenging. Thereis less precedence for such as design. The suit must either be light enough to be able to

flex and move under human power, or it must be self-powered through the use of stored

portable battery power. It must still maintain nominal atmospheric pressure for the

occupant, and must provide the oxygen and water needed by the occupant, all whilesafely removing, immobilizing, and/or storing waste products the occupant generates for

the duration of the exploration service period.

The suit must provide all of the com, nav, visual inputs, and voice encoded outputs that

are associated with the much larger spaceborne EMU, while in a higher dust, static, andpotentially higher RF interference environment.

The suit must also be durable enough to endure the repeated mechanical manipulation

and friction contact with Martian surface features and human rated tools, while reliably

maintaining internal pressure and internal systems integrity.

Figure 2.4.2-1, SMU LST Context Diagram

Martian Atmosphere

Martian Regolith

SurfaceMobilityUnit

Surf InhabitantInfo:


Access

VisualInput

A/Vs

O2, H2O

Support,Pressure

Voice

Touchcmd

WasteStorage

Info:C3I

Mechanical

Manipulation

ContactThrust

Net ThrustForce

C2O

Martian Atmosphere

Martian Regolith

SurfaceMobilityUnit

Surf InhabitantInfo:


Access

VisualInput

A/Vs

O2, H2O

Support,Pressure

Voice

Touchcmd

WasteStorage

Info:C3I

Mechanical

Manipulation

ContactThrust

Net ThrustForce

C2O


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3. HATLEY-PIRBHAI (HP) TEMPLATES FOR MISSIONS TO MARS

The Hatley-Pirbhai (HP) diagram may be used to further organize functional concepts,

including Living System Theory (LST) functions, for a more coherent utilitarian view of

how functions interrelate, and for auditing the interfaces between LST functions. The

general form of an HP diagram is shown in figure 3-1.

Figure 3-1, The General Form of the Hatley-Pirbhai (HP) Diagram [5]

The Hatley-Pirbhai (HP) context diagram divides functionality according the how it

relates to system externals. It is a variant of a context diagram in the sense that it definesa system in the context of its external interfaces. Input and output processing have their

own categories, as do user facing interfaces. Inward facing internal monitoring functions

also have their own category, maintenance and self test, and all processing not engagedin either outward facing or inward facing data processing is considered to be part of

central processing.

3.1 Generalized ME HP Template

If we use the preceding guidelines to map mass-energy LST categories to HP diagrams,

we achieve the results shown in figure 3.1-1. Following the convention that inputs are on

the left, user interfaces are on top, outputs are to the right, maintenance and self test

(overhead, or inward facing) functions are on the bottom, and central processingfunctions are in the middle, figure 3.1-1 shows how matter-energy living system theory

functional categories map to an H-P context diagram.

As expected, [ING] appears on the left, and [EXT] and [REP] appear on the right. [PRD]

generally represents the user, and is shown on top, but can also be a central processingfunction. Most motorized functions [MOT] are overhead in nature, and are therefore

represented on the bottom, but can be an output as well, as in attitude control or

propulsion functions. Support [SUP], boundary [BND] and matter energy distribution

InputProcess

Central Processing

OutputProcess

User Interface Processing

Maint. and Self Test


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Figure 3.2-1, ME HP Example for Transhab ECLSS [3]

3.3 Generalized IP HP Template

If we use the preceding guidelines to map information processing LST categories to HP

diagrams, we achieve the results shown in figure 3.3-1. Input [INT] and decoding [DCD]functions appear on the left, output [OUT] and encoding [ECD] functions appear on the

right, the decider [DEC] functions here generally represent user interfaces shown on top,

and overhead functions shown on the bottom include internal transducers [ITL] andautonomous association functions [ASC]. This leaves network [NET], timing [TIM], and

memory [MEM] functions as central.

While LST categories predate the invention of the internet and were far in advance of

cloud computing architectures, the parallel to modern network based architectures isstriking. The boundary [BND] label is not included in the figure but could be thought of

as two boundaries, an outer one surrounding the entire diagram, and an inner information

assurance enclave, that includes the core functions surrounding the network [NET],memory [MEM], and time keeping function [TIM].

ING: AirRecircluation

DST: CabinAir Return

EXT: TraceContaminate

Removal

STR: Air

MOT:Cabin Air

Circ

CNV:Oxygen

Generation

PRD: AirTemp &

HumidityControl

EXT: H2Overboard

Venting

AirSupply

LSS Users: Crew

H2OSupply

ING:

Condensate

ING: UrineRecovery

STR: H2O

PRD: PotableWater

Processing

ContaminationRemoval

O2 System

EnvironmentalControlSystem

MOT:Water

Pumps

Key:

EXT: CO2Removal

Solids

STR:

Nutrition

EXT:Waste Mgt

STR:Spare

Oxygen

Input Output

User I/F

Processing

Overhead


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Inputs [INT] and outputs [OUT] are composed of communication devices and sensors,

supported by the necessary decoders [DCD] and encoders [ECD] respectively,presumably over which navigation and timing data is made available and from which nav

and timing may be derived.

The network [NET], time-keeping [TIM], and memory [MEM] reside in the inner

processing enclave, and the ECLSS monitoring [ITL] and any Kalman filtering or otherprocessing needed to derive navigation solutions [ASC] are in the housekeeping and

overhead enclave. In the user interface is the crew with their controls and displays, cast in

the role of the decision element, or decider [DEC].

4. FLOW REQUREMENTS FOR MISSIONS TO MARS

4.1 People Flow as defined by Mission Profile

Personnel flow is now briefly considered here to help bring clarity to the missioncontexts. As depicted in figure 4.1-1, the flow of personnel for the typical mission can be

divided into three mission segments: and outbound transit segment, during which theTranshab will sustain the lives of the crew, a surface visit segment, during which the

Surfacehab must sustain the crew, and the return transit segment, during which theTranshab must again be depended upon for sustenance.

Figure 4.1-1, Mission Directed Personnel Flow, Time and Distance

The periods of time over which each of these segment last will need to be integrated intime to determine the provisions and consumables required by the crew, and is heavily

distance from Earth

time

Outbound

TransitSegment

SurfaceVisit

Segment

ReturnTransit

Segment

launch

TMI burn

Mars landing

Mars ascent

Earth reentry

E M

distance from Earth

time

Outbound

TransitSegment

SurfaceVisit

Segment

ReturnTransit

Segment

launch

TMI burn

Mars landing

Mars ascent

Earth reentry

distance from Earth

time

distance from Earth

time

Outbound

TransitSegment

SurfaceVisit

Segment

ReturnTransit

Segment

launch

TMI burn

Mars landing

Mars ascent

Earth reentry

E M


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dependent on the amount of recycling that is possible in each habitat, as well as in situ

resource utilization on the Martian surface during the surface stay and possibly also forreturn transit use, if launched from the Martian surface with the returning crew.

4.2 ME Flows in the Transhab Context

Give the period of time the Transhab will be occupied during the transit segments the

mass and energy flows occurring in the Transhab will be very significant for sustainingthe lives of the crew. The major flows of mass and energy needed for ECLSS is shown in

figure 4.2-1. Collection [ING] of solar energy will be through the use of solar panels.

Typically these panels convert solar energy to voltage and current, used to chargebatteries or fuel cells for energy storage [STR]. The energy will be used to power

propulsion, ECLSS, and IP systems. Waste energy in the form of excess heat must be

disposed of via passive high emissivity radiative panels which radiate thermal photons

directly into space [EXT]. In the ECLSS context the major mass flows are the O2 to CO2loop, shown at the top, and the clean water to waster water loop shown on the bottom of

the diagram. Both loops should maximize recycling [CNV] to minimize storage [STR]requirements.

Figure 4.2-1, Mass-Energy Flows in the Transhab Context

O2, H2O, and food are the key consumables. It is necessary to quantify the consumables

needed to support a crews metabolism and resupply in order to size life support systems

and determine needed supplies. This is captured in table 4.2-1.

Sunlit SpaceTranshab

Shaded Space

CrewCrew

O2 STR CO2 CNV

EnergySTR

FoodSTR

H2OSTR

WasteCNV

Crew

INGsolarpanel EXT

otherwasteheat

EXTwasteeject

EXTradiativecooling

Sunlit SpaceTranshab

Shaded Space

CrewCrew

O2 STR CO2 CNV

EnergySTR

FoodSTR

H2OSTR

WasteCNV

Crew

INGsolarpanel EXT

otherwasteheat

EXTwasteeject

EXTradiativecooling


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Table 4.2-1, Consumables needed to support a crew [6]

Consumable Requirement (kg/person-day)

Portable Water (includes food rehydrationwater) 1.6 - 3.6

Hygiene Water (toilet, shower, clothing wash) 5 - 25

Oxygen 0.6 - 1

Buffer gas leakage 0.5 - 2

CO2 production (for removal) 0.7 - 3

Food (containing 2/3rds bound water) 1.5 - 2

Cooling water for EVAs 3.5 - 5.5 (kg/person-EVA hour)

One readily observes from the table that the range of required consumables is highly

variable, depending on the mass and metabolism of the individual astronaut, the range ofactivities they are performing, and the availability and application of various resource

handling technologies.

4.3 ME Flows in the Surface Hab Context

The mass-energy flows expected in the Surfacehab context are shown in figure 4.3-1.

Figure 4.3-1, Mass-Energy Flows in the Surfacehab Context

Martian Atmosphere

Crew

Surfacehab

Martian Regolith

Crew

O2 STR CO2 CNV

EnergySTR

FoodSTR

H2OSTR

WasteCNV

Crew

INGsolarpanel

EXTconvectivecooling

INGgreen

houseproduce

EXT

otherwasteheat

CNVsanitizer

RegolithCNV

INGmined

regolith

EXTwasteeject

Martian Atmosphere

Crew

Surfacehab

Martian Regolith

Crew

O2 STR CO2 CNV

EnergySTR

FoodSTR

H2OSTR

WasteCNV

Crew

INGsolarpanel

EXTconvectivecooling

INGgreen

houseproduce

EXT

otherwasteheat

CNVsanitizer

RegolithCNV

INGmined

regolith

EXTwasteeject


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The energy flow on Mars will be less than a comparable system on Earth due to the

reduced solar flux. The solar panels will therefore have to be scaled up accordingly. Butthe consumables picture in the Surfacehab context is considerably more promising. Due

the relatively extensive resources of the Martian atmosphere and regolith, mass flows

[ING] should be and will be substantial so as to lessen the storage requirements [STR].

While recycling [CNV] will still be important, the efficiency of the recycling will notneed to be as high given the resources available for food, water, and even potentially

oxygen replenishment.

These mass flow contexts may be further decomposed using LST functional categories asshown in figure 4.3-2 for the example of a waste treatment CNV function. Each step

depicts both the activity type, such as screening and aeration, as well as the LST

stereotype, such as [DST] and [CNV]. Ideally a UML/SysML modeling language (suchas SparxEATM) should be used for functional decomposition of this nature so that the

resultant requirements can be captured and ported to a requirements management tool

such as DOORSTM, and subsystem requirements can be shared and negotiated withbiotechnology vendors just as they are now with aerospace hardware vendors.

In this instantiation there is reclaimed water separated first and then additional treatment

applied to reclaim drinking quality water, but in practice it may simplify the process and

reduce steps to just treat all reclaimed water to drinking quality.

Figure 4.3-2, Typical Wastewater Recycling Process Flow in the Surfacehab Context

ScreeningDST

Waste CNV

(sludge to dewatering fordisinfection & disposal)

EXT H2O:Class A

reclaimedwater

EXT H2O:Drinking

qualitywater

SeparationDST

ING Raw Waste Influent

EXT solidwaste

disposal(and / or

composting)

PrimaryDisinfection

CNV

OzoneTreatment

CNV

Flocculation &Clarification

CNV

ZeeweedTM (


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5. CONCLUSIONS

From the observations, analysis, and discussions of this paper we conclude that:

There is utility in the use LST categories for modeling and developing therequirements of sustaining living systems, such as in human space flight missions,

in all their various contexts. Hatley-Pirbhai (HP) Diagrams may be useful for organizing and categorizing LST

categories in both the Mass-Energy domain and in the Information Processing

domain.

The following activities are recommended as future work areas:

Derive detailed mass, energy, and information budgets as a function of crew sizefor various Transhab and Surfacehab contexts.

Begin partitioning the context diagrams presented by splitting functionality intoservice modules and living quarters, and document the associated interfaces.

Develop dynamic models and simulations of ECLSS using Living Systems

Theory (LST) that incorporate diurnal and activity induced variations in loading. Recommend LST categories as standard functional stereotypes for UML and /or

SysML to the OMG, in order to better enable more uniform system modeling for

Human Spaceflight Systems in general, and ECLSS systems in particular.

6. ACKNOWLEDGMENTS & DISCLAIMERS

Approval for the publication of this paper by the LinQuest Corporation is gratefully

acknowledged. Disclaimer: This paper represents one approach to life support systemsmodeling and should not be construed as design guidance for ECLSS or any life support

system. The views expressed in this paper are solely the authors and do not represent the

position or views of the LinQuest Corporation, the United States Air Force, or any otherorganization.

7. REFERENCES

[1] Miller, James Grier, Living systems. (1978). New York: McGraw-Hill. ISBN 0-

87081-363-3.

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Documents

2013 Living Systems Theory for Missions to Mars - Companion Paper