NASA Technical Reports Server (NTRS) 19930017506: In-situ materials processing systems and bioregenerative life support systems interrelationships

4 Pages·0.13 MB·English

by  NASA Technical Reports Server (NTRS)

In-Situ Materials Processing Systems and Bioregenerative Life Support Systems
Interrelationships
George V. Mignon and Robert J. Frye
Environmental Research Laboratory
Abstract
This project was to investigate the synergy and linkages between bioregenerative life support
systems and the materials produced by in-situ materials processing systems. Such systems
produce a broad spectrum of byproducts such as oxygen, hydrogen, processed soil material,
ceramics, refractory, and other materials. Some of these materials may be utilized by
bioregenerative systemseitherdirectlyorwithminormodifications. The main focusof thisproject
was to investigate how these materials can be utilized to assist a bioregenerative life support
system. Clearlythe needto providea sustainablebioregenerative lifesupportsystemfor long term
human habitation ofspace Issignificant.
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Approach
In orderto narrow our investigationwe chose a lunarmissionscenario inwhich a fully functional
bioregenerative lifesupport systemwould be fully Implemented at base maturity.
There are four basicfunctionsthat anylifesupport systemmust achieve:
AtmosDhedc Reaeneratlon
The atmosphere ofanylifesupportsystemneedstohavecontaminate gases suchasCO2,CO, HC,
etc.., removed and replenished with02. This isaccomplished ina bioregenerative system by the
interactionofmicro-organismsandhigherplants. Abioregenerativesystemwillenablethe complete
recycling of these gases by utilizationof CO2 and production of 02 by photosynthesis and the
removal of contaminant gases by soil microorganisms residing in the substrate used for plant
growth.
Water Purification
Water purificationcan be easilyachieved by physicochemical means, however water recycling is
not so easy. Within a bioregenerativesystemwater isrecycled and purifiedby the mechanism of
plant evapo-transpiration and condensation on cooling coils. The only lossesInthis cycle would
bedue to leakage and export ofwater.
Waste Pro_ssin 0
The major waste to be processed is human waste. These wastes are really basic nutrients for
growingplantsandwithpropertreatment (composting,etc...) can be readilyIncorporated intoasoil
based bioregenerative system.Waste would be stored during base establishment and processed
(forpathogen removal)vianon-destructivemethods Thewastematerialwouldthen belatterutilized
with lunar regolith to develop a livingsoil system. As organic matter is a limitingcomponent of
bloregenerative systemsinspace,allpotentiallyusableforms oforganic matter mustbe conserved
for later re-use. The organic matter usedto construct a soil from lunar regolith will provide the
necessary cation exchange capacity and nutrient retention characteristics necessary to provide
optimal microbial communities andthus higher plantgrowth. Re-use ofhuman and other forms of
organic material is a necessary component in closing the cycles of bloregenerative life support
systems. The major thrustofour effortshasbeento quantify the available nutrientswhich may be
efficientlyrecycled.
Food Production and Processinq
The fundamental function ofa bioregenerativesystemistofacilitatethe production offood through
the support of higher plant growth and development. In the absence of energy and technology
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intensivehydroponic culturing,soilmicroorganisms providethe nutrient regulation mechanism for
food production. Underthe proper conditions higherplantsand soilmicroorganisms constitute an
integrated system of high reliabilityand stability.
The basicelements required byabioregenerative systemare carbon, hydrogen, oxygen, nitrogen,
and phosphorus. The firstfour are relatively abundant in organic matter and through correctly
deslgned recyclingsystemscan beconservedandcontinuouslyrecycled.Theothermacro-nutrients
required, potassium, magnesium, calcium, andsulfurare availableinlunar regolithand would not
belimiting.Micronutrlentssuchasiron,manganese,zinc,copper, boron, molybdenum and chlorine
can be supplied initiallythrough terrestrial sources.A mature bioregenerative lifesupport system
will maintainthese nutrients Inadequate quantitiesand Inuseable forms.
The Moon, asfar aswe know, does not contain adequate quantities of water or nitrogen in any
useable form. Thesetwo items may bethe limitingfactors inthe productivity of a bioregenerative
life support system. If local sources of water cannot be found or produced then all water must
ultimately originate from terrestrial sources. Food production could provide one part of a water
reuse system through transpirationand condensation. Nitrogen may ultimately be harvested from
the atmosphere usingnitrogenfixing microorganismsthatform symbiotic relationshipswith higher
plants.
The lunar regolithcontains much ofthe essential materials necessary for a good agricultural soil.
The availabilityofthese nutrientswillnot beknown untillivingsoilsystemscan beconstructed from
reprocessed human waste, othertransported organic matter and lunarregolith.
Conclusion
It isvery apparent that some form of bioregenerative lifesupport systemwill be required for long
duration space missionssuchasalunarbase. Theextent of closurewillbe determined bydesign
tradeoff betweencost ofresupplyandthe firstcostofestablishment ofthe bioregenerative system.
For a lunar base scenario itisalso evidentthat there are really onlytwo basic insitu materials of
great benefit to abioregeneratlve system;lunar oxygen and lunar soil. A detailed literature study
hasbeenconducted andcitationscompiled. Thereport,tabulatesandsummarize therequirements
for a bioregenerative lifesupport system on a per person day basis and what materials can be
provided bythe proposed insituprocessingschemes.
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