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by: Laila Windler


Laila Windler

GPA 3.96


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This 40 page Class Notes was uploaded by Laila Windler on Friday October 30, 2015. The Class Notes belongs to ASEN 5116 at University of Colorado at Boulder taught by Staff in Fall. Since its upload, it has received 27 views. For similar materials see /class/232171/asen-5116-university-of-colorado-at-boulder in Aerospace Engineering at University of Colorado at Boulder.

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Date Created: 10/30/15
W MARS 0R RUsT LLC 600 ECLSS Subs stem 610 Overview 611 Objective Within the Mars habitat design it is necessary to develop a new Environmental Control and Life Support System ECLSS Some of these issues include the inability to quickly return home living in a range of gravity conditions and the psychological factors that will arise from a long duration highrisk mission In order to meet the system and mission requirements available life support technologies will be analyzed and integrated The Mars Design Reference Mission DRM document will be used as the baseline mission and an approach will be developed to provide a comprehensive life support system that will optimally satisfy the needs of the Mars DRM 612 Class Speci c Scope The scope of this project is to research relevant technologies and determine an integrated system that will successfully accomplish the abovementioned objective This section of the project was completed over the course of the Fall 2002 semester for 3 credit hours There were two reports from two different teams that were used to find the optimal design for the ECLSS subsystem 613 System Design Philosophy The ECLSS subsystem is separated into four subsystems Atmosphere Water Waste and Food The four subsystems are then integrated into one functional system Figure 611 shows the subsystem interactions with the human in the loop All subsystems interact with one another on different levels All subsystem interactions are taken into account and an iterative system design is implemented to maximize efficiency The final ECLSS subsystem is based off the optimum individual subsystems that interact best with the other subsystems while maintaining a high overall system performance Individual subsystem requirements and assumptions will be analyzed while taking into account the overall system requirements and assumptions previously laid out An iterative design of the overall system and its subsystems is completed to determine the optimal way of meeting all requirements Because of time limits on this project it was decided that the most important product should be a workable system Trade studies were not considered a priority and as a result the system that was chosen was a combination of two papers that were final reports in a previous class ASEN 5116 These were Shidemantle Ritch et al 2002 and Kungsakawin Nancy et al 2002 The base design components for the food waste and atmosphere subsystem came directly from Shidemantle s report while the water subsystem came from Kungsakawin s report The full references for these papers are included at the end of this report Page 1 of 40 MARS 0R RUsT LLC Figure 6131 Subsystem Interactions 6 2 0 Requirements As mentioned earlier The Environmental Control and Life Support subsystem ECLSS is responsible for providing a physiologically and psychologically acceptable environment for humans to survive and maintain health in the Mars habitat This includes providing and managing food water waste and atmospheric conditions as well as supplying crew accommodations and medical services To determine how to provide what is necessary requirements must be determined Toplevel requirements which are also known as level 1 requirements are requirements that are stated in the DRM From those assumptions and level 2 requirements can be derived Top Level requirements and level 2 requirements for the ECLSS subsystem are given below T 017 Level Requirements Provide life support functions for a crew of 6 180 worstcase transit time between Earth and Mars 600 day worstcase surface stay on Mars Perform the entire mission assuming no resupply from Earth Take advantage of ISRU when possible Operate during launch transit descent and surface gloads Provide 2 levels of backup life critical Do not rely on biological systems for life support functions Provide as much loop closure as possible Reliability maintainability and safety Derived Requirements and Assumptions 0 Shall provide adequate atmosphere gas composition and pressure control 0 Must have necessary Gas Storage for mission duration 0 Must have adequate Ventilation Page 2 of 40 W MARS 0R RUsT LLC 0 Must provide Trace Contaminant Control 0 Shall provide Temperature and Humidity Control 0 Must have Fire Detection and Suppression 0 Must supply entire crew with adequate sources and amounts of food and potable water for a 46 month transit to Mars and 600day stay on the surface of Mars 0 Shall be able to collect and store liquid solid and concentrated wastes for immediate and or delayed resource recovery 0 Must provide adequate supply of hygiene water 0 Shall provide psychological support by taking into account crew environment and other human factors 0 Shall monitor and report radiation levels in habitat to other subsystems 0 Mass must not exceed 4661 kg 0 Target life support system power usage of 121 kW 0 Must allow for crew input to habitat temperature and humidity levels 6 3 0 Atmosph ere Subsystem The purpose of an atmosphere management subsystem is to maintain an acceptable atmosphere for human life For a Mission to Mars analysis of the system level requirements revealed that the subsystem would operate in 13g gravity This exercise will push the current limits in knowledge about longterm reliability and functionality The following evaluation accounts for these system level concerns in the design approach and in the discussion of subsystem level integration results 6 3 1 Responsibility and Assumptions An acceptable atmosphere for human life on a Mars mission consists of providing a safe environment that meets the physiological and psychological needs of the crew This general requirement translates into subsystem process tasks These tasks are oxygen provision pressure regulation thermal control trace contaminant control carbon dioxide control and fire detection and suppression For most of these tasks the selected technologies must provide the basic functionality while maintaining the key parameters within a specific range of values The ecosystem of the Earth incorporates most of the tasks in the regulation of the atmosphere as a whole and in specific areas On a large scale the atmosphere provides oxygen 31 psia pp02 to humans removes metabolic byproducts trace contaminants and carbon dioxide and maintains a buffer that regulates temperature pressure and relative humidity with physicalchemical and biological processes However with changes in latitude longitude and altitude there are can be distinct changes in temperature total and partial pressures and relative humidity In an enclosed environment these same tasks operate with a smaller buffer size however the same basic requirements still need to be met For the first task oxygen needs to meet the base metabolic oxygen demand of 1 kg Ozpersonday along with Page 3 of 40 W MARS 0R RUsT LLC losses due to oxidative technology demands The ECLSS subsystem is also responsible for supplying the EVA subsystem with all the life support needs Considering all the leakages and EVA needs the cabin still has to maintain a 31 psia ppOz with an acceptable range of 283 to 335 psia ppOz The total pressure is regulated to 102 psia due to the frequency of EVA scheduled to the crew The combination of oxygen and nitrogen results in variations of the total pressure is possible The thermal control system maintains relative humidity between 2570 and temperature between 183 C 7 267 C Carbon dioxide removal needs to offset the metabolic production rate of 085 kg COzpersonday in addition to technology products that interact with the crew cabin atmosphere Humans material offgassing and technologies generate a variety of organic and inorganic compounds ammonia nitric oxide methane ethylene and benzene in volatile state or adsorbed to particulates that need to be controlled below the long term Spacecraft Maximum Allowable Concentrations SMAC which are 7 mgm3 09 mgm3 3800 mgm3 340 mgm3 and 02 mgm3 respectively Finally on Earth fires are eventually selflimiting but in an enclosed environment the final task of fire detection and suppression needs to operate quickly and reliably to avoid both direct life and limb and indirect oxygen consumption hazards Eckart 1996 632 Design Approach The evaluation of the atmosphere subsystem entailed a multitiered approach This approach iteratively examined requirements key mass drivers and the functionality and integration of different technologies The air subsystem requirements were driven by the toplevel requirements and derived from known and assumed technology specific data The key mass drivers were identified in the baseline mission scenario which consisted of only existing and allowable nonregenerable technologies These mass drivers were then initially examined to minimize consumables After gathering information and ranking current technologies a functional subsystem was created and then iteratively changed to maximize the reuse or recycle of materials to reduce mass losses while still conforming with the top level and subsystem level requirements 63 3 Technologies and Trade Study To understand the key mass drivers and interactions a baseline system with existing non regenerable technologies used on Space Shuttle ISS and MIR was created The basic system details and interactions are shown in Table 6331 and Figure 6331 The key mass drivers for the baseline system were the carbon dioxide removal 46 oxygen provision 38 and total pressure regulation 13 systems These identif1ed systems are all high in consumable mass As a first cut for mass savings the oxygen nitrogen and carbon dioxide system variables are reviewed to determine options for the minimization of consumables The consumable mass for the carbon dioxide removal system is due to the LiOH canisters which translates into mass savings dependent completely upon the selected carbon dioxide removal or reduction technology The mass of the oxygen system was sized for humans 915 venting 79 leakage 06 and technology 0 usage similarly the total pressure regulation system was sized only for Page 4 of 40 W MARS 0R RUsT LLC leakage and EVA venting At this level the potential areas for mass savings are reductions in the leakage and venting of oxygen and nitrogen race Contaminant Given the 145 kgday predicted leakage rate of the Habitat under normoxic conditions 1009 kg of N2 and 441 kg 02 will be lost to the Martian environment each day For the 600day mission therefore the minimum required buffer tank sizes are 6056 kg and 2644 kg for N2 and 02 respectively However this system trade has several potential disadvantages an increase in the percentage of oxygen and thus ammability reduced heat rejection capacity of the air and the unknown long term effects of living at reduced atmospheric pressure with normoxic oxygen levels Page 5 of 40 MARS 0R RUsT LLC cabin leakage N2 storage tanks it crew cabin control To trash v v I l I l compactor To trash TO hyglene To trash water tank compacth Hfzo Figure 6331 Baseline nonregenerable PhysicalChemical Air ECLSS Schematic This schematic illustrates the basic subsystem level intraand interactions for the air management system The remaining mass savings in this system are based on the selection of individual candidate technologies and maximization of recyclables for compatible subsystem and system level interactions Initially information on a variety of technologies for meeting the different tasks was compiled into spec sheets These technologies were then sized in a similar fashion to the baseline system calculations to meet the associated task In the case of missing information for a specific technology some assumptions were made After the technologies were reasonably detailed the technologies were ranked based upon their equivalent system mass in Table 6332 Page 6 of 40 MARS 0R RUsT LLC Table 6332 Air Management Life Support Technology Rankings SM Technologies TRL E RANK Oxygen SPWE w EDC 9 2119 1 SPWE w Sabatier 9 4394 2 SPWE wo Sabatier 9 5515 3 Tank cryogenic 9 6573 4 O2 chemical TRK 9 7496 5 Tank pres vessel 9 7681 6 Total Press Reg Nitrogen Tank cryogenic 9 2224 1 Tank pres vessel 9 2562 2 Carbon Dioxide Removal or Reduction EDC 6 162 1 SAWD 6 190 2 4BMS CDRA 8 418 3 Sabatier CDReA w H2 tanks 9 450 4 Bosch 6 885 5 LiOH 9 9333 6 Thermal and Humidity Control CHXrotating 6 267 1 Detection 9 150 1 Treatment TCCA 9 135 1 T003 9 201 2 Activated Charcoal 9 In TCCS amp TCCA Catalytic Oxidation 9 In TCCS amp TCCA Particulate Filters 9 In TCCS amp TCCA FDS Detection ISS Photoelectric 9 21 1 STS Ionization 9 21 2 Suppression Nitrogen Agent 9 68 1 Halon 1301 Agent 9 68 2 CO2 9 85 3 Depressurization 9 694 4 Note ESM mass 00115 kgkW power 9 kgm3 volume 00069 kgkW heat rejection l kgcrewhour crew time 5 kg total surchargeTRL less than 9 The highest ranked systems were subsequently analyzed and deemed compatible However further analysis was required to determine the potential recyclables between the selected oxygen generation system solid polymer water electrolysis SPWE and the carbon dioxide reductionremoval systems Sabatier Bosch and electrochemical depolarized concentrator For the primary option A Figure 6332 there is a high degree of water return from the EDC to the SPWE which reduces the additional water Page 7 of 40 W MARS 0R RUsT LLC supply required to produce oxygen from 5250 kg H2O to 1854 kg H2O see Table 6333 Option B Figure 6333 has a lower degree of water return from the Sabatier reactor which only reduces the additional water supply required to produce oxygen from 5250 kg H2O to 4129 kg H2O see Table 6334 Based on these tradeotfs along with the xed mass differences the option A saves 2500 kg of mass over option B and 14000 kg of mass over the baseline scenario Table 6333 PhysicalChemical Air Life Support System for Mars Mission Option A Heat Crew Subsystem Selection Mass Power Volume Produced Time TRL O2 Provision SPWE 2096 184 224 184 9 Total Pressure N2 pressure Regulation tanks 2562 0 0 000 0 9 CO2 removal EDC 133 030 02 067 54 6 Temperature amp Rotating Heat Humidity Control Exchanger 175 131 39 082 205 6 Trace Contaminant Control TCC GCMSTCCA 273 008 09 018 4 9 N2 extinguishers Fire Detection amp amp photoelectric Suppression detectors 80 0003 03 000 6 9 Total 5319 353 75 351 379 Notes 1 Acronyms SPWE solid polymer water electrolysis EDC electrochemical depolarized concentrator GCMS gas chromatographymass spectrometer TCCA trace contaminant control system catalytic oxidation activated carbon amp particulate lters 2 SPWE mass includes the consumable water supply Table 6334 PhysicalChemical Air Life Support System for Mars Mission Option B Heat Crew Subsystem Selection Mass Power Volume Produced Time TRL O2 Provision SPWE 4371 184 224 184 2 9 Total Pressure N2 pressure Regulation tanks 2562 0 0 000 0 9 Sabatier w H2 removalreduction Tanks 389 00006 03 00029 35 9 Temperature amp Rotating Heat Humidity Control Exchanger 175 131 39 082 205 6 Trace Contaminant Control TCC GCMSTCCA 273 008 09 018 4 9 N2 extinguishers amp Fire Detection amp photoelectric Suppression detectors 80 0003 03 000 6 9 Total 7850 32 101 28 67 Page 8 of 40 ESM 2119 2562 162 88 5485 ESM 4394 2562 88 8048 MARS 0R RUsT LLC cabin A leakage N2 storage tanks a 2quot gt crew cabin S PWE A EDC2 7 V To vent From H20 tank T0 vent TO39 hyglene TO39 trash quot water tank compactor Figure 6332 PhysicalChemical Air Life Support System Schematic Option A This schematic illustrates the subsystem level intraand interactions for the air management system option A Page 9 of 40 MARS 0R RUsT LLC cabin leakage A crew cabin A control From H20 tank T0 vent To hygiene To 3511 1 water tank compactor 2 Figure 6333 PhysicalChemical Air Life Support System Schematic Option B This schematic illustrates the subsystem level intraand interactions for the air management system option B 634 Design The subsystem generally operates autonomously to control process functions and airwater ow rates with optional crew control of the temperature set point Since Option A was selected the processes and its functionality are detailed in Figure 6332 and Table 6333 and represent the unsupplemented operational state of the subsystem on Mars On Mars a tertiary option may be exercised in case of a partial or full failure of the fuel generation system ISRU due to filter clogging This option would entail the direction of the excess H2 and C02 from atmospheric subsystem to the ISRU unit by a sealed source Speci cally there are nine nitrogen tanks for the mission and one tank will be empty Page 10 of 40 W MARS 0R RUsT LLC upon landing with a second tank available in 30 days after arrival These tanks could be retro tted to capture the H2 and C02 and secure them for use by the ISRU system The analysis of the atmosphere subsystem intra and interactions proved integral information to the determination of the optimal system In the baseline system design the key mass drivers were the carbon dioxide removal oxygen provision and total pressure regulation systems With the addition of alternative physicalchemical technologies the key mass drivers shifted to oxygen and nitrogen provision system due to leakage and EVA losses The values for heat power and volume for the completed atmosphere system are located below in table 6341 Table 6341 Heat Power and Volume for ECLSS atmosphere technologies Heat Generated Power Volume Spectrometer GOMS 64 0 Water Subsystem The baseline water management requirements are to provide potable and hygiene water to the crew for the duration of the mission As outlined in the human mass balance section 3905 kg6 person crewday of potable water and 2365 kg6 person crewday of hygiene water must be provided and meet the water quality requirements 6 4 1 Responsibility andAssumptions The requirements for water management are de ned in Table 6411 All the water that the crews will receive has to meet the following requirement for the purpose of maintaining the health of the crews Water will be tested using the monitoring technologies that will be discussed later in Water subsystem If the water does not meet the standards it will be sent back for future processing Table 6411 Water Quality Requirement Maximum Contaminant Levels Page 11 of 40 MARS 0R RUsT LLC Dissolved Gas free 37 C Free Gas iodine Manganese Page 12 0f 40 W MARS 0R RUsT LLC 6 4 2 Design Approach The rst step in the design process involves calculating a baseline system The baseline system is simple All the water will be lifted and carried for the entire mission duration However this accounts for a mass of nearly 99198 kg of water Closing the water loop by recycling urine hygiene water and atmospheric condensate will make very signi cant mass savings Candidate technologies were then identi ed to close the loop and were ranked taking into account TRL mass power volume ef ciency and hazard level Winning technologies were then integrated into the water subsystem 6 4 3 Technologies and Trade Study The baseline architecture is simple The water comes from the storage and all the water was taken with the crew Page 13 of 40 W MARS 0R RUsT LLC To Waste Management 25 Laundry 9 4 Hygiene 18216 Potable 0 214 Food at Crew Accommodation Figure 6431 Open Loop Diagram w Flow Rates in kgday for 6 Crewmembers Table 6431 Water Management Parameters BLISS kg Power lav 991980 Volume 1113 600 Days Figure 6431 shows the baseline system block diagram for the water management subsystem The only components needed to operate the system include storage and delivery The storage mass was assumed to be 20 of the stored mass Water processing technologies were broken down into two main categories Potable and Hygiene processing and urine processing since urine needs more treatment than hygiene water Table 6432 shows the candidate technologies considered for the potable and hygiene water processing Table 6432 Hygiene amp Potable Water Treatment Candidate Technologies Wquot M Function Candidate Technologies Page 14 of 40 W MARS 0R RUsT LLC Wquot M Function Candidate Technologies Hygiene amp Potable Water Treatment 0 MIR Technology Condensate10 0 Reverse Osmosis RO1713 o Multiflltration MF113 o Electrodialysisl 0 Oil and Water Seperationz o RockPlantMicrobial Filtering System14 o Thermoelectric Integrated Membrane Evaporation TIMES1 o Granular Activated Carbon GAC5 o Aqueous Phase Catalytic Oxidation Subsystem APCOS Ultrafiltrtionlo MilliQ Absorbtion Beds Pasteurization Ionic Silverl Regenerable Microbial Check Valve Iodine1215 UVvisible Spectrophotometer laser11 Due to the signi cant list of candidate technologies a series of selection criteria needed to be used to rule out undeveloped technologies TRL levels less than 6 and complete lack of information were the primary criteria used to reduce the number of candidate technologies Further elimination of technologies was performed during the formation of the spec sheets due to key information such as mass or power missing The potable and hygiene water processing consisted of numerous technologies each consisting of unique pre and post treatment processes This required the development of systems of different technologies to be traded between Hygiene and potable water will be processed with the same system Consumable data is primarily described for complete processing to potable quality water therefore the data is not available for a unique hygiene water processing trade The following systems were traded UltraFiltrationReverse Osmosis APCOS UltraFiltrationReverse Osmosis MilliQ Absorbtion Beds Multifiltration The UFRO and MilliQ Absorption Beds won the trade Multiflltrations downside was its large consumable mass while the APCOS was signi cantly penalized due to the unknown oxygen consumption for the oxidation process Microbial control was separated from this trade study due to its need in any system chosen Due to lack of information the Iodine Microbial Check Valve was chosen Iodine removal beds are also required before potable use to eliminate longterm effects of Iodine consumption Page 15 of 40 W MARS 0R RUsT LLC Urine processing is separated from hygiene water processing due to its complexity Table 6433 shows the candidate technologies for urine processing Table 6433 Urine Treatment Candidate Technologies W39ater lVIanagement Function Candidate Technologies Urine Treatment I MIR Technology evaporation steam condensation sorption electrolysis10 Vapor Compression Distillation VCD1713 Vapor Phase Catalytic Ammonia Removal VAPCAR1 Air Evaporation AES1 Aqueous Phase Catalytic Oxidation PostTreatment System APCOS1013 Super Critical Water or Wet Oxidation SCWO1 Incineration oxidation11 Pyrolysis Aerobic Slurryll Aerobic Solid Processing composting11 Anerobic Solid Processingn Aquaculture fish11 Electrochemical Oxidation Again this large list of technologies was reduced through a few selection criteria The primary selection factor in urine treatment was the elimination of biological systems following the DRM requirements TRL levels below 6 and lack of information rules out many of the other candidates Due to the severe elimination of technologies by initial selection criteria only two were left The urine distillation trade was performed between the following technologies Air Evaporation System AES Vapor Compression Distillation VCD Vapor Compression Distillation won the trade study with the Air Evaporation System in second The primary reason the AES places second was due to the high power consumption of 1 kW This is approximately 10 of the allotted power for the spacecraft dedicated to one system A simple trade between carrying makeup water in the VCD only system versus using an ABS to process the brine water on a low duty cycle resulted in a significant mass savings of approximately 175 kg as well as providing a very simple redundant system in the case of a VCD failure Page 16 of 40 MARS 0R RUsT LLC Crew Accommodations sh ower washer sinks t39c To SWE andFood Subsystem 1 39 To Food Potal1ampWateI tam Accommodations I v From Waste To Waste Subs3stem Subsystem Figure 6432 Closed Loop Water Management Flow Diagram Figure 6432 shows the integration of the water management subsystem components The urine treated by the VCD must be pretreated with Ozone a commercial oxidizer and sulfuric acid to prevent the release of ammonia during the distillation process Brine water from the reverse osmosis lter is also passed through the VCD to reclaim more water The water ow through the VCD can be arranged in numerous forms and is not completely shown on this diagram Brine water from the VCD can be passed back through itself to maximize the solid concentration of the brine The remaining brine water is stored and periodically processed by the AES Current AES testing shows a slightly reduced quality of water from the AES so this water is reprocessed through the VCD to ensure complete processing of the urine Product water from the VCD is combined with the remaining wastewater from the craft including that from hygiene The water stream then ows through an Ultra ltration unit which consists of mechanical ltration media This increases the lifetime and ef ciency of the following reverse osmosis lter As stated earlier the brine water produced in processed through the VCD The product water then ows through the MilliQ absorption bed which consists of activated carbon and a proprietary organic carbon scavenger media to reduce the TOC to acceptable potable water quality standards At this time Iodine is then added to the water stream for microbial control Monitoring then checks the PH conductivity TOC and Iodine levels before the water is stored Hygiene water is used directly from this source Potable water must rst be passed through the iodine removal bed to reduce the iodine level to acceptable amounts Online iodine monitoring then ensures this level Page 17 of 40 MARS 0R RUsT LLC Water Monitoring is a major subsystem within the water management Therefore any technology that has the Technology Readiness Level TRL of less than 7 is assumed to be unacceptable for life critical component and not studied in this section The TRL of 7 indicates that the system prototype has been demonstrated in a space environment However if the technology is not gravity dependent the acceptable TRL is said to be 5 At this TRL level the component andor the breadboard have been validated in relevant environment and shows promising evidences that it would also work in space With this in mind the first tread study would be to do the simple passfail elimination due to the TRL level Table 6434 List of Technologies amp Associated TRLs Therefore the technologies that will be studied are the following 1 Electronic Nosell for taste metals NOC and odor TRL 611 Page 18 of 40 MARS 0R RUW LLC L ImnmniL Nos llxpux39imcm llp 200D anachud m hm cm or Figure 6433 Electronic Nose Equipment 2 Ion Speci c Electrodes ISE11 for conductivity level TRL 2811 4 ra m liIi uumu are nunhnlII H IF runpun u gun u lulll Iul 1 MI TIT at lm ullgdzudI 1w madam 4 Figure 6434 Ion Speci c Electrode 3 Total Organic Carbon TOC conductivityu TRL 6 Pressure W H 9 quot039 Raslsuvlly uvmmm Rnslsumy 3 Carrol We Sensor 1 Sense 7 2 Va He s a x ouauen r h H 3 sample mmmm m Rasslivlly W Snusm 3 J l quotd wmii39 Bram Iii mm L umc I A i Tnmpamwm 1 Figure 6435 Total Organic Carbon Conductivity Diagram Page 19 of 40 MARS 0R RUsT LLC Figure 6436 Actual Total Organic Carbon device 4 Conductivity TRL 8911 Figure 6437 Sample of Conductivity device 5 Test Kits for pH chemstrips for speci c compounds TRL 5911 Figure 6438 Sample Test Kits Table 6435 Water Sample Requirement for OffLine Monitoring initial On Orbit Operations Location Sample Volume Frequency ECLSS Storage Tank 500 mlday Every day Random Tank or Use Port 500 mlday Every 2 Lays Avg Total Volume 5250 mlweek Avg No Sa ple 105 timesweek Page 20 of 40 W MARS 0R RUsT LLC Table 6436 Water Sample Requirement for OffLine Monitoring Mature Operations 500 No 110 Since each technology can detect different contaminates in water the trade study cannot be conducted to compare them to one another The combination of all the technologies is considered to be the best arrangement The repetition of the monitoring provides for the redundancy of the subsystem ISE Conductivity pH Iodine TOCCOD hardness TOC TOCCOD Conductivity Gross quality indicator Electronic Nose Odor taste Test Kits Conductivity pH Iodine TOCCOD Hardness Figure 64310 The Order of Monitoring Devices 644 Design Current technology provides a substantial choice of operational subsystems within water management Detailed testing has been performed on several occasions and provides excellent information on physicalchemical and biological systems Many promising technologies in development or in use have been developed in the private sector and almost all information is proprietary While these technologies could provide the optimum solution to our design requirements they had to be eliminated or severely penalized within the trade study due to the lack of detailed information The water buffer capacity of this system is 32428 kg In an event of total water system failure this allows for 14 days under normal potable water use without any hygiene use This should be enough time to address the issue This is a very critical design feature that will Page 21 of 40 W MARS 0R RUsT LLC signi cantly affect the mass and safety of the system Further research or testing is needed on this subject The values for heat power and volume for the completed water system are located below in table 6441 Table 6441 Heat Power and Volume for ECLSS water technologies Heat Generated Power Volume 6 5 0 Waste Subsystem The waste subsystem is designed to maintain simplicity while minimizing the consumables and maXimizing the things that can be recycled 651 Responsibility andAssumptions The Waste Management Subsystem for the mission to Mars requires that all waste be processed in an ef cient manner Waste management is a mission critical issue and must be handled appropriately Failure of the spacecraft s life support system to handle mission generated waste materials will ultimately cause the loss of the spacecraft habitat balance and effectively reduce the overall function of the crew to a minimum at best The waste subsystem shall collect and store liquid solid and concentrated wastes for immediate andor delayed resource recovery Longterm storage shall be provided for nonrecovered wastes and unprocessed items The waste subsystem should be capable of handling approximately 11092 kgday of human biomass and technological waste products from a 6person crew Eckart 1996 Table 6511 shows the breakdown for each of these products Page 22 of 40 W MARS 0R RUsT LLC Table 6511 Waste product breakdown for a 6 person crew Eckart 1996 T amp 652 Design Approach As stated above several different technologies were considered as viable options for the Waste Management Subsystem Speci cation sheets were generated for each of the technologies and judged according to TRL Design Simplicity Crew Safety and Reliability Trade studies were then conducted with regard to each of the technologies and rated according to each of the priorities stated above Simply stated the approach in designing a waste subsystem should be to deliver a system that is both reliable and comprised of proven technologies 6 5 3 Technologies and Trade Study The waste subsystem selected for the mission to Mars consists of l urinefeces collection mechanism toileturinal and 2 ISS trash compactors The system designed for the Mars mission meets the simplicity reliability safety and TRL requirements for the waste subsystem Several other technologies were considered for the subsystem One technology which was rather enticing was the SuperCritical Water Oxidation method of processing waste Using this strategy 9999 of the waste is broken down into some usable component The SCWO would have been an ideal candidate for the waste subsystem but because of its low TRL N3 high operating pressure and temperature and the fact that it has yet to be own in a space environment it had to be dropped from the available pool of technologies Using the SCWO would have sufficiently closed the loop for the Waste Management Subsystem Pyrolysis was another technology that operates at high temperature and high pressure resulting in high power consumption This technology would also close the loop of the waste subsystem All the gas generated would return to the atmosphere subsystem water will be return to the water management subsystem and the trivial amount of carbon will be stored Other technologies considered but not used were electrochemical incineration photocatalytic oxidation and other combustion methods However all of these methods either required too much consumable mass too much power or were not considered safe enough to use Also it was determined that there would be enough water on board the spacecraft so that water loss from not processing the fecal water would be tolerable This trade allowed for the consideration of a ight proven method of handling waste products instead of one with a lower TRL Page 23 of 40 MARS 0R RUsT LLC Urinal Commode E 39 W R fecal quot storage compactor solid waste compactor S orage M VCD i From TCCA TO waste tra39Sh k food trash water tan I microfiltration Figure 6531 Schematic of the Waste Management Subsystem There are two inputs for the system 1 human and 2 biomass and technological wastes such as spent cartridges from the TCCA and VCD lters The Water Management Subsystem will process the urine The ow of waste through the waste subsystem follows the schematic in Figure 6531 Human waste is deposited in either the commode or the urinal Fecal matter and associated toiletries are deposited by the crewmember into a fecal bag The fecal bags are then placed into one of two trash compactors The compactor for fecal matter will use small UV degradable bags before placing into larger trash bags Trash from TCCA cartridges amp lters food packaging and microfiltration devices are placed into a compactor Both the fecal waste and other solid waste are then placed into hermetically sealed bags for long term storage The fecal matter will breakdown and become fertilizer for future mission During the surface stay 600 days the crew will place all the trash in the designated storage area outside of the habitat during the frequent EVA scheduled or be stored inside the habitat due to the concern about the Mars environment contaminations Whether the storage of trash will be outside or inside will have to be determined after performing a study to determine amount of contamination is performed This is because MOB is very sensitive to the issues surrounding the contamination of the surface of Mars Page 24 of 40 W MARS 0R RUsT LLC 654 Design Although many different waste processing methods are readily available here on earth very few of these technologies have been tested in similar environments to that of space and even fewer have been ight tested in microgravity The Waste Management Subsystem selected for this mission meets the requirements of simplicity reliability and safety The waste system used has a xed mass of 279 kg a consumable mass of 23 kgday and has a total power consumption of 022 kW The toileturinal used for the mission has been ight proven on both the Space Shuttle and the International Space Station This system requires minimal power and its reliability is proven The crew will have a provision of fecal bags and compactor bags for the duration of the mission plus 10 Having such a large provision ensures that the crew will have enough resources for the entire mission plus any contingency Finally the waste subsystem selected for the mission is capable of handling more than the required 11012 kgday of waste This exibility was an important element in the nal selection of this speci c system One of the potential drawbacks to this system is that it does require crew interaction for the collection of the fecal matter While this may have a negative psychological impact on the crew overall failure of a more complex waste system was deemed to have a much larger impact Future considerations should give preference to the SuperCritical Wet Oxidation method and Pyrolysis for processing waste because of its ef ciency and capability of handling both human and technological waste products The values for heat power and volume for the completed waste system are located below in table 6541 Table 6541 Heat Power and Volume for ECLSS waste technologies Heat Generated Power Volume 6 6 0 Food Subsystem The objective of this stage of the Mars mission project is to provide an analysis of the food subsystem requirements and available technologies necessary for food supply The functional requirement is to meet the nutritional needs of the astronauts in a safe and healthy manner while taking into account the conditions of 1 3g gravity Eckart 1996 Page 25 of 40 W MARS 0R RUsT LLC 661 Responsibility andAssumptions The Mars Design Reference Mission DRM document was reviewed to develop an approach to provide a comprehensive life support subsystem and a food supply for the crew The DRM shows that siX crewmembers must be supplied with enough food for 600 days stay on the surface of Mars Drake 1998 In order to determine mass and volume of food to supply crewmembers an average of 2200 kCal was assumed for this system This is based off the fact that a minimum of 2000 kCal is needed per person per day to keep the astronauts healthy Miller 1994 Many trade factors needed consideration in the design of the food subsystem 662 Design Approach One of the predominant trade factors is physiological nutritional need versus psychological palatability and desires The requirement for this system is to meet the nutritional needs of the astronauts in a safe and healthy manner Klaus 2002 The intake of food for energy purposes needs to be sufficient to maintain weight and composition of the body and allow levels of activity anticipated for operations in space Lane 2000 The basic nutritional needs dictate the amount of food that is necessary to bring A minimum of 2000 kCal is needed per person per day to keep the astronauts healthy and an average of 2200 was chosen for this system Miller 1994 Nutritional needs are important but factors related to changes in body composition and energy eXpenditure at different levels of gravity must also be taken into account The relationship between diet and exercise must be considered because that can affect the levels of kilocalorie intake 6 6 3 Technologies and Trade Study In choosing types of food for the mission considerations include minimal in ight preparation minimal waste inedible biomass and packaging ambient stowage minimal mass shelf life and good taste For a long duration mission stability variety and production during the mission need to be considered Food stabilization defines packaging requirements and necessary mass allocations Food supply stabilization has evolved from food fed through a tube for the Mercury missions to dehydrated sources for the Gemini missions to adding thermo stabilized and irradiated items during the Apollo missions Current day brings us to the Shuttle STS and the International Space Station ISS both of which have all of the aforementioned items as well as intermediate moisture and natural form foods ISS and STS also have condiments to add avor since food tastes bland in space Klaus 2002 PhysicalChemical PC systems cannot produce food However this system has been chosen to be a PC system and in so doing all food must be brought If food production is considered then those considerations include plants animals aquaculture and other technologies Animals are impractical as that brings up inefficiency factors therefore they will not be considered Aquaculture is more practical because of rapid growth and steady state production Aquaculture requires a large mass of water which can also be Page 26 of 40 W MARS 0R RUsT LLC used as an emergency buffer for water supply This is something to consider for future research and design All of the aforementioned factors and technologies must be combined to create a system that meets nutritional needs palatable desires and minimization of waste and mass When designing the food subsystem the first step taken in the design approach was to consider the requirements and to identify candidate technologies These candidate technologies were then researched and put into a trade matrix Once all candidate technologies were part of the matrix any unknown values were researched Unfortunately due to limited available detailed information often times because the information is proprietary to a company not all necessary values were found for the candidate technologies This posed a problem in calculating ESM and choosing a technology because any decision to be made would have to be made with a certain lack of information The food subsystem is different than the other subsystems because variety is a requirement and in order to achieve this more than one candidate technology must be chosen For example a variety of different foods are being brought and will be stabilized using different stabilization methods After the matrix was ranked it was sent to the System Engineer to pick the top technologies that best integrate with the rest of the life support subsystems and in some cases the top 4 were chosen After a final system was chosen mass calculations were finalized To develop a food supply subsystem various parameters had to be explored food supply food production food storage and food processing For this mission all food will be brought Bringing all of the food required for surface stay is necessary for safety precautions mainly because all of the food supply bio regenerative technologies have fairly low TRLs If the astronauts had to rely on bio regenerative technologies for their food supply then they risk the possibility that those technologies would fail leaving the astronauts without enough food for the trip When bringing food a variety of stabilization methods were examined There is always the possibility of bacteria contaminating one type of food or food stabilized using a certain method This is part of why variety is so important Because variety was considered a J 39 t 39 39 39 J therrno tabili ed natural form irradiated and intermediate moisture were chosen for use in this system Precooked and frozen were eliminated due to lack of a refrigerator A refrigerator provided will not be used for storing frozen food but will be used for refrigerating drinks and minor food preparations The total mass for stabilized food is approximately 2787 kg which is a minimum value An extra 10 of this value was taken and brought as a buffer To calculate this mass number the value of 062 kg day per person was taken and multiplied by the number of crewmembers and the length of the trip Miller 1994 Food storage methods are defined by the way the food required to be stocked Storage methods utilized at room temperature are mainly based on different ways of packaging Page 27 of 40 W MARS 0R RUsT LLC the food These include cellulose used for biodegradable rigid packaging bioplastics used for biodegradable rigid packaging edible rice wafer used for biodegradable rigid packaging aluminum or bimetallic tins for thermo stabilized foods retort pouches for thermo stabilized foods exible pouches for natural form foods and intermediate moisture foods foil laminate bags for beverages and dropper bottles for condiments All of these packaging methods are going to be used because of the need for variety Different types of food have to be packaged differently The other type of food storage is refrigeration The candidate technologies include a Coolant Loop Vaporcompression Refrigeration Stirling Cycle Heat Pump Thermoelectric Heat Pumps Therrno acoustic Refrigeration and Phasechange Materials Due to power constraints storing food by refrigeration was not chosen for this system Food processing defines how the astronauts prepare the food for consumption Various technologies that were considered include a microwave roasting and baking water re hydration uid immersion and direct contact andor radiant heating Two technologies were chosen a microwave that can also be used as a convection oven and grill and a sinktap that can be used to rehydrate and heat food as well as be used for drinking purposes The specs for these technologies are in table 6631 Table 663 1 Food Technolog pecs Food Quantity Mass Power Volume Heat Crew Time TRL Technology each each each Produced Microwaves 2 33 kg 1 kW 03 m3 1 kW 62 hrs 6 Convection Oven Grill Sinktap l 5 kg 1 kW No4 m3 1 kW 0 9 Refrigerator 1 200 kg 1 kW 1 rrr3 1 kW 0 9 NOTE Parentheses indicate an educated estimate Page 28 of 40 MARS 0R RUsT LLC 39 food preparation water refrigerator m1crowave 4 food amp Food waste amp d nk ll u 11 packaging food storage Potable water To trash compactor quot 6 6 4 Design Figure 661 Food System Schematic Operation of the food subsystem is fairly straightforward The operation of the system is laid out in the food schematic in Figure 61 When it comes time to eat one or all of the astronauts will retrieve packaged and stabilized food from storage The food can then be prepared in the microwave or by using water from the sinktap The excess food and packaging is then thrown away The final resulting food system is a preliminary system Many parameters are still unknown but the basics values and the structure of the food system have been decided This primary system is the best system possible while taking into account its inte ration into the entire life support system This primary food system has a mass of and is made up of stabilized food a microwave which can also be used as a convection oven and grill a sinktap with hot and cold water to rehydrate food and for drinking purposes The values for heat power and volume for the completed food system are located below in table 6641 Table 6641 Heat Power and Volume for ECLSS food technologies Food System Heat Generated Power Volume kW kW mquot3 Mass k Page 29 of 40 W MARS 0R RUsT LLC dehydrated 6 7 0 Integrated System 6 71 Integration Process The four systems discussed in the previous sections Atmosphere Water Waste and Food combine to form an integrated system that addresses the mission needs regarding environment and life support within the habitat Beyond the ECLSS Subsystem the ECLSS components operate in conjunction with other subsystems to meet mission goals During the integration process ECLSS collected requests from the other subsystems of needs for ECLSS support and also presented requests to other subsystems for support Trade studies were performed on each of the ECLSS technologies considering their overall integration within the MOB Habitat with a focus on minimizing mass maximizing efficiency and minimizing mission and program risk Through this process solutions were found that meet the needs of both ECLSS and the other MOB subsystems and the following design emerged 6 72 Integrated Design The integrated ECLSS design is shown in Figure 6721 The integrated system provides greater efficiency than would be possible with four independent ECLS systems The interactions of the four main ECLSS functions are evident in the diagram Page 30 of 40 E MARS 0R RUsT LLC Food Water System w Hygiene Water Iodine Removal Bed ISE Monitoring Potable Water Pretreated Urine V Pretreatment Oxone Sulfuricacid J Atmosphere System TCCA Waste System Urine Atmospheric Mfrs I Condenser Atm Solid Waste Processed water Liauid Waste Solid Waste Gases Figure 6721 MOB ECLSS Integrated Desigi Starting with the Food System and proceeding clockwise around the diagram the Food System receives potable water from the Water System This water is used both to re hydrate food and for drinking with or without powdered drink mixes The Water System also provides water to the Atmosphere System This water does not need to undergo the additional treatment to qualify as potable water so it exits the Water System as hygiene quality water increasing the ef ciency of the overall ECLS Subsystem The Waste System is also integrated with the Water System When crewmembers eliminate urine it is then passed to the water system for rigorous treatment allowing the ECLS Subsystem to reclaim the valuable water for future use Finally the ECLSS design integrates collection of waste by passing waste from the Food System and Trace Contaminants Control System to the Waste System The waste from the Food System will include a combination of packaging plastics and food waste generated during meal preparation and clean up 6 73 Integration with other subsystem Page 31 of 40 MARS 0R RUsT LLC The previous discussion and diagram focus on the integration within the ELCSS Subsystem The interfaces between ECLSS and the other subsystems are presented in Figure 6731 Page 32 of 40 MARS 0R RUsT LLC ISRU Plant 39 I RoboticsAutomation structures Legend I I Oxygen lgt I I Nitrogen 4 Carbon Dioxide dgt I CabinAir gt I Trace Contam gt ISRU d Thermal I A gt uh n f A ECLSS r gt IV n gt a gt vo a gt W Audio 7 77gt C3 2 Packetized Data 7 r gt gt TCPl a a a a a a a a r a a a r gt c c EVAs Electrical Power l P We39 Al Heal gt gt Nuclear Reactor V 1 Crew Accommodations Crew Mars Com Satellites Figure 6731 MOB interfaces between ECLSS and all other subsystems Page 33 0f 40 W MARS 0R RUsT LLC The interfaces between ELCSS and the other subsystems will be described starting with the interface between the Power Subsystem and ECLSS and proceeding clockwise on gure 6731 6 731 Power Inteiface with ELCSS The Power Subsystem provides power to all the ECLSS components requiring power This includes conditioning of the standard Habitat 28 VDC power to meet the needs of various components The average ECLSS power demand is estimated to be 96 kW A breakdown of the ECLSS equipment power needs is presented in Table 6721 Table 6721 ECLSS total mass power and volume estimates ECLSS Technologies Totals for each Subsystem 3 Stem Heat Generated Power kW 1999 0363 418 38643 ECLSS system Total 10406 6 732 CCC Interface with ECLSS The CCC Subsystem is responsible for the control and command of the ECLSS components Telemetry is sent from the various ECLSS equipment to the CCC computers The computers then use this information to control the ECLSS equipment appropriately The telemetry is also distributed by CCC to Earth Mission Control and the Master MOB database for future use in troubleshooting and trend analysis See Section 90 for more information on the design and operations of the CCC Subsystem 6 7 3 3 Thermal Inteiface with ECLSS ECLSS interfaces with the Thermal Subsystem by rejecting heat to and receiving heat from the Thermal subsystem as needed to maintain the proper temperatures of the ECLSS equipment More information on the design and operations of the Thermal subsystem are presented in Section 70 6 7 3 4 Structures Interface with ECLSS The Structures Subsystem and ECLSS interact via the habitat s atmosphere ECLSS vents the atmosphere through the Habitat outer structure Also ECLSS will gradually lose a fraction of the Habitat atmosphere as a result of leakage through the exterior walls The Habitat is being designed to contain leakage to less than 145 kgday In addition Structures supports ECLSS by providing the structure and volume in which the ECLSS equipment is housed The total estimated mass and volume of the ECLSS Subsystem is 100953 kg and 272 m3 respectively as shown in table 6721 These totals include consumables at start of mission The details of the current best estimates are presented in Table 6721 and Sections 63 through 66 6 735 ISRU Interface with ECLSS Page 34 of 40 W MARS 0R RUsT LLC Although ECLSS is not dependent on the products of the ISRU it will make use of these products if they are available The ISRU is designed to produce nonpotable water Oxygen and food for use by ECLSS The utilization and testing of the integrated ISRUECLSS system will provide valuable information for future crewed Mars missions Also through production of spare consumables the integrated ISRUECLSS system decreases the overall mission risk Section 30 provides more information on the design and operations of the ISRU plant 6 7 3 6 EVA Inteiface with ECLSS There are several interfaces between the EVA Subsystem and ECLSS Food potable water and Oxygen are provided by ECLSS to the EVA suits for use when a suit is donned Through natural human processes occurring inside the EVA suit trace contaminants and Carbon Dioxide are produced that must be removed from the atmosphere inside the suit These elements are returned to the ECLS Subsystem for processing Due to the length of extravehicular activities it is necessary to provide crewmembers the ability to eliminate urine and feces These liquid and solid wastes are collected within the EVA suit by specially designed diapers These diapers are then returned to ECLSS for processing Also ECLSS supplies EVAS with Nitrogen and Oxygen for use in pressurizing and depressurizing the EVA airlock See Section 110 for more information on EVA suit design and operations 6 7 3 7 Crew Interface with ECLSS ECLSS supplies four elements essential to life to the crewmembers food water Oxygen and Nitrogen Through the food storage and food preparation components of the ECLS Subsystem the crew receives the nourishment needed to stay healthy The crewmembers receive the proper air makeup and pressure needed by their bodies through the Oxygen and Nitrogen supplied by the controlled atmosphere Again through natural human processes COz trace contaminants Oxygen and Nitrogen are returned from the crewmembers to ECLSS for processing Also urine and feces produced by the crewmembers are returned to ECLSS for processing and storage respectively 6 7 3 8 Crew Accommodations Interface with ECLSS The final set of interfaces between MOB subsystems and ECLSS is the set of interfaces between ECLSS and Crew Accommodations ECLSS provides both potable and non potable water to the Crew Accommodations Subsystem The potable water is used by Crew Accommodations in operation of the dishwasher kitchen sink and crew mouthwash and face wash faucet Crew Accommodations requires nonpotable water for operation of the clothes washing machine and crew shower Dirty water is produced through use of these various Crew Accommodations components and is then sent back to ECLSS for processing to reclaim the water Heat from the Crew Accommodations equipment in particular the clothes dryer and dishwasher is released into the Habitat interior atmosphere ECLSS manages this additional heat through operation of the heat exchanger More information on the design and operations of the Crew Accommodations can be found in Section 120 6 7 4 ECLSS consumables Page 35 of 40 MARS 0R RUsT LLC A large portion of the mission mass comes from the consumables Food water oxygen and nitrogen all need to be carefully calculated Table 6741 shows an overview of the major consumables Table 6741 Total Mass and Volume values for Consumables It was assumed that the crew would not obtain any food from the Martian environment therefore all necessary food for the mission must be brought to Mars A day s ration of food that is completely dehydrated weighs 13 kg 35 kg completely hydrated In general the higher the water content the better the food tastes therefore for a long duration mission such as this it was decided that 23 kgpersonday would provide a comfortable diet The water needed to hydrate this food is 12 kgpersonday Packaging is about 05 kgpersonday A ten percent margin was then added in order to provide an extra element of safety Table 6742 shows how much water is designated for common tasks The subtotal values for one were calculated for siX crewmembers Table 6742 Water The water needed to rehydrate the food was discussed earlier Each crewmember needs to take in 35 kg of water a day in order to stay healthy and active It was found that the total water in the hydrated food is 22 kg so each astronaut needs to drink 13 kg in order to intake that water they need The amount of water for hygiene laundry dishes and cooking was based on previous missions When calculating how much water was needed to ush the toilet each day it was assumed that each crew member would urinate around 5 times a day The EVA cooling water number was calculated based on the assumption that there will be two EVAs a week each having two crewmembers It is also important to note that this calculation is based on a regenerable nonventing heat sink The value Page 36 of 40 MARS 0R RUsT LLC of 014 kg is the average amount of water that will need to be replaced before each EVA on top of this value 55 kg will need to be added for the very first EVA for each suit Finally the amount of oxygen and nitrogen needed to be decided upon The amount of oxygen and nitrogen for the habitat airlock and rover were calculated based on the volume 61575 m3 35 m3 and 23 m3 pressure 102 psi and temperature 23 C This number includes the amount of each gas that will be needed to make up for the loss due to leakage and cycling the airlock 10 of the total airlock air The nitrogen will be brought to Mars in tanks but the oxygen will be produced from water via SPWE 6 75 Veri cation of Requirements Below in table 6751 there is a description ofthe requirements for the ECLSS subsystem and to the right of that show whether the requirement was met or not and how it was met with the design The table shows that all requirements for ECLSS were met except for the requirement that mass must not exceed 4661 kg The mass is only exceeded by approximately 200 kg and with more iteration of the current design the mass can most likely be reduced Table 6751 Table of Requirements and how they are met by the current desigi 6 7 6 Failure Mode E ect Analysis The failure mode effect analysis FMEA of ECLSS has to be studied in order to formulate the best possible arrangement in case failure occurs in the system Each subsystem of ECLSS has its own specific concerns that are apparently unrelated to other subsystems therefore the FMEA of each subsystem is addressed separately The effort to fix the problem depends entirely on the cause Tracking down the component or components that fail is the key to solving the problem In this section of the report the potential cause of each crisis is determined The technique of repair is not covered in this sectlon Page 37 of 40 W MARS 0R Rim LLC 6 7 6 1 Atmosphere Subsystem Within the atmosphere subsystem there are potentially 6 problems that can occur total pressure is too low total pressure is too high ppO2 is too low ppO2 is too high trace contaminant is too high and re in the cabin If one of the above crises occurs the appropriate action should be executed If the total pressure of the cabin is too low the crews will no longer have shirtsleeve environment and this will violate one of our toplevel requirement in the ECLSS subsystem The cause of this problem can be due to malfunction of the sensor which detect the problem low level of N2 alone low level of O2 alone and leakage which potentially lead to low level of air in the habitat Malfunction sensor is always one of the possibilities to con rm that the sensor is working a back up sensor should be used to verify the first sensor In case of N2 or 02 level being too low there are 4 possibilities supply line is broken supply line is clog or restricted broken valve or valves and the storage tank is empty which lead to low pressure in the storage tank and the pressure gradient which is the mean of delivering the gas is no longer exists Repairing replacing and resupply have to be considered In the last case of leakage there must be a failure in the structure of the habitat since the leak rate was predicted but any failure in the habitat s structure would lead to more leakage than previously predicted Proper cause and action is addressed in the Structure FMEA section of this report Another problem that can take place is the total pressure becoming too high As mentioned before malfunction sensor can be the case of this fault alarm but too much N2 and 02 can also be the reason of this increase in pressure Too much of the two gases can be due to broken valve or valves or leakage in the supply line inside the habitat structure If however the ppO2 is too low normoxic condition is no longer present The cause of low ppO2 can be due to too much N2 This is the only possibility since the multiple failures will not be addressed ie if there s a normal level of N2 and ppO2 level is dropped then the total pressure of the habitat is too low in which case the problem is already being addressed in the previous paragraph The reason of high level of N2 is the same as previously mentioned There can be broken valves and leakage in the supply ling inside the habitat structure Another problem is of cause the malfunction sensor If the ppO2 is too high the air can affect the ammability property of the air and fire is more likely to occur The cause of this problem can be due to low level of N2 in this case the same cause from low total pressure section from previous paragraph can be applied Tracecontaminant is another problem in the habitat The level of the tracecontaminant is monitored at all time The TCCA system see Atmosphere Subsystem Section should take care of the tracecontaminant to keep an acceptable range However if the trace contaminate is too high the only cause other than malfunction sensor is the TCCA system The crew should then fix or replace the technology Page 38 of 40 W MARS 0R RusT LLC Fire is another major problem that the atmosphere subsystem is responsible for When the re occurs the N2 extinguisher should suppress the re instantaneously If this system fails to go off the re will have to be manually suppressed by the crews The cause of the re is faulty wiring and other over heating and malfunction of other technologies 6 7 6 2 Water Subsystem Within the water subsystem there are 4 different failures that can arise potable water doesn t meet the standard hygiene water doesn t meet the standard there is no potable water delivery and no hygiene water delivery Each of these problems would be discovered at the faucet where the water is to be used If this occurs then there is no sensor to detect the failure other than the visual observation of the crews Therefore there should not be any malfunction of sensor If the water doesn t meet the standard inside the water treatment the water would of cause be retreated Therefore the malfunction sensor in this case would be the sensor inside the water processing system Damaged or any failure in any of the technologies could also contribute to the cause of this problem for both hygiene and potable water In the case of no water delivery the cause would have to be due to the failure in the delivering process Broken pipe restricted pipe broken valves and broken pump anywhere in the system could be the cause 6 7 6 3 Waste Subsystem Since the waste subsystem is very simple the only technology that can fail is the compactors Over ow of the toilet is caused by a malfunction of the fecal genie compactor If the fecal genie is not working the rst logical thing to check would be if the UV biodegradable bag is out Secondly the compactor itself can also be broken In this case the crews have to X or replace the compactor For other waste such as food packaging the compactor can also be malfunction The cause is the same as the fecal genie technology 6 7 6 4 Food Subsystem Food subsystem has even less components than the waste subsystem The only critical technology that is in the system is the microwave oven If the microwave ovens are not working then there might be a power outage or the ovens simply are broken Repairing and replacing of the ovens have to be considered 6 8 0 Conclusion It is concluded that successful completion of a PhaseA equivalent study has been accomplished for the design of a fullup Life Support System to facilitate a human mission to Mars All subsystems have been effectively integrated into one functional system The functional Life Support System design successfully satis es all the design requirements and assumptions that have been laid out Page 39 of 40 MARS 0R RUsT LLC 681 Limitations This project had two major limitations lack of adequate time and information The project was given three months to complete a PhaseA equivalent study while most NASA PhaseA studies typically last on the order of siX months Because time played such a large factor it was more difficult to research all areas of the candidate technologies The lack of information is mostly due to organizations not sharing detailed technical information either because of proprietary reasons or International Trade and Arms Regulations ITAR 682 Recommendations First thing that is needed to improve upon the system is to develop partnerships with organizations to obtain and share detailed information on selected technologies To take it from there the system should be analyzed for weaknesses and redesigned to improve efficiency Special attention should be paid to the lower TRL technologies ie 6 s and 7 s to take them up to 8 and 9 Take a look at more supplemental technologies ie Aquaculture and ISRU and see if they can be incorporated into the system to improve efficiency It would also be beneficial to research some of the newer technologies ie those with low TRLs and determine if they have the potential to be verified technologies and incorporated into the system before the launch dates Page 40 of 40


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