The development of a controlled Ecological Life Support System (CELSS) will require NASA to develop innovative monitoring and control technologies to operate the different components of the system. Primary effort over the past three to four years has been directed toward the development of technologies to operate a biomass production module. Computer hardware and software required to operate, collect, and summarize environmental data for a large plant growth chamber facility were developed and refined. Sensors and controls required to collect information on such physical parameters as relative humidity, temperature, irradiance, pressure, and gases in the atmosphere; and PH, dissolved oxygen, fluid flow rates, and electrical conductivity in the nutrient solutions are being developed and tested. Technologies required to produce high artificial irradiance for plant growth and those required to collect and transport natural light into a plant growth chamber are also being evaluated. Significant effort was directed towards the development and testing of a membrane nutrient delivery system required to manipulate, seed, and harvest crops, and to determine plant health prior to stress impacting plant productivity are also being researched. Tissue culture technologies are being developed for use in management and propagation of crop plants. Though previous efforts have focussed on development of technologies required to operate a biomass production module for a CELSS, current efforts are expanding to include technologies required to operate modules such as food preparation, biomass processing, and resource (waste) recovery which are integral parts of the CELSS

Knott, William M.

Sager, John C.

English

NASA Technical Reports Server

N91-24060
MONITORING AND CONTROL TECHNOLOGIES FOR BIOREGENERATIVE
LIFE SUPPORT SYSTEMS/CELSS
William M. Knott, Ph-D.
and
John C. Sager, Ph.D.
ABSTRACT
The development of a Controlled Ecological Life Support System (CELSS) will require NASA to develop
innovative monitoring and control technologies to operate the different components of the system. Primary
effort over the past three to four years has been directed toward the development of technologies to operate a
Biomass Production Module. Computer hardware and software required to operate and collect and
summarize environmental data for a large plant growth chamber facility has been developed and refined.
Sensors and controls required to collect information on such physical parameters as relative humidity,
temperature, irradianee, pressure, and gases in the atmosphere; and PH, dissolved oxygen, fluid flow rates,
and electrical conductivity in the nutrient solutions are being developed and tested. Technologies required to
produce high artificial irradiance for plant growth and those required to collect and transport natural light
into a plant growth chamber are also being evaluated. Significant effort has been directed towards the
development and testing of a membrane nutrient delivery system potentially useful in growing plants in the
microgravity of space. Robotic and plant imaging systems required to manipulate, seed, and harvest crops,
and to determine plant health prior to stress impacting plant productivity are also being researched. Tissue
culture technologies are being developed for use in management and propagation of crop plants. Though
previous efforts have focused on development of technologies required to operate a Biomass Production
Module for a CELSS, current efforts are expanding to include technologies required to operate modules such
as food preparation, biomass processing, and resource (waste) recovery which are integral parts of a CELSS.
INTRODUCTION
The Controlled Ecological Life Support System (CELSS) is developing the science database required to
build and operate an bioregenerative life support system in space. Such a system has been identified to be a
requirement to develop a permanent presence in space (Paine, 1986/1/; Robbins, 1988/2/). There is
insufficient data at this time to predict when such a system will be economically feasible for a specific mission
scenario or what components will be included in a functioning CELSS. However, if humans are going to be
anything other than visitors in the space environment, such a system must ultimately be developed. The
current CELSS program is a research and development effort which should grow steadily into a major
hardware development program after a sufficient science and technology database exists.
The CELSS Breadboard Project (Koller, 1986/3/; Prince and Knott, 1989/4/) being conducted at the
Kennedy Space Center has as its major goal the development and operation of an initial CELSS at a one
person scale to demonstrate feasibility for the development of such a system. This project was initiated in late
1986 with the first research data being collected on biomass production in 1988. The current schedule is for
the initial Breadboard CELSS configuration to be completed in 1993 and tested by the end of 1994. The
components or modules being developed for inclusion in the initial CELSS Breadboard are as depicted in
Figure 1. There are four major modules, Biomass Production, Biomass Processing, Food Preparation, and
Resource Recovery. For either one of these modules to be operated successfully will require a major
enhancement of monitoring and control technologies. This presentation will describe the CELSS Breadboard
Project, discuss current technologies being developed, and identify requirements for new technologies
necessary for monitoring and controlling the system.
THE BREADBOARD PROJECT
The current Breadboard Project is centered around a large atmospherically sealed plant growth facility,
the Biomass Production Chamber (BPC) (Figure 2), which was constructed to measure energy use and mass
161
https://ntrs.nasa.gov/search.jsp?R=19910014747 2020-03-19T17:44:15+00:00Z
flow through a crop community over its entire life cycle. A series of experiments are being conducted in the
BPC to evaluate crop species in this closed environmentally controlled facility (Wheeler and Sager, 1990/5/;
Wheeler et. al, 1990/6/). During these trials, emphasis is being placed on the effect of different environmental
conditions on plant growth, CO 2 exchange, water use, and mineral uptake. Microbiological sampling and
analyzes are conducted during each plant growth study in order to determine the functional relationships
between the microorganisms and the plants, especially in the rhizosphere. Total biomass production is
measured for each crop as the plants are harvested from the chamber. Other modules of a CELSS which are
required to convert this biomass into food and to recycle all materials back to the plants are being developed
in laboratories adjacent to the BPC. The edible biomass is transferred to the processing laboratory (kitchen)
so that meals can be prepared and tested. Various processing procedures are being evaluated in order to
determine amount of time required to accomplish the task, to identifyequlprnent requirements, and to
evaluate the meals for nutritional value and palatability. The inedible biomass is transferred to the resource
recovery lab so thai valqous subcomponents tTaa_mayconvert this maten'-aT_to::an :_ible substance can be
evaluated. These subcomponents include aquaculture, enzyme degradation of cellulose into sugars, and fungal
production processes. Material left over from either the food preparation or biomass processing activities
must be converted to CO 2 , water, and minerals for return to the Biomass Production Chamber. Resource
recovery subcomponents that are currently-being tested to accomplish this include a leachate reactor and
aerobic microbiological reactors.
Tests of each resource recovery subcomponent is designed to obtain mass flow data through each
component in the context of a total integrated system. Emphasis is being placed on the cycling of carbon,
hydrogen, oxygen and nitrogen along with selected major minerals. A related activity will evaluate total
pyrolysis of the edible biomass to determine the products generated and the energy used. The measurement
of water cycled through each subcomponent of the Breadboard is of major interest during all project activities.
The water loop on the BPC is currently being closed and hygiene water being used by the human along with
his liquid waste will be measured and recycled through the appropriate subcomponents.
The initial total Breadboard system is scheduled to be complete by 1993. Extended testing of this system
will occur during 1993 and 1994. A total reconstruction of a CELSS, the Integration Test Facility, at a three
to four person scale is scheduled for 1995.
ADVANCED TECHNOLOGY DEVELOPMENT
One of the major problems encountered to date in the construction and operation of the Breadboard
CELSS is the reliability of the physical systems required to maintain the biological organisms, The biology has
been very reliable and predictable but the monitoring and controlled technologies required to maintain a
proper environment for the organisms has been unreliable. Several objectives need to be met as we attempt
to improve the technologies required for the successful deployment and operation of a CELSS in space.
Monitoring and control technologies must be developed to minimize energy use and limit manpower
requirements. The elements must be miniature in size, light in mass, and durable. Their measuring
capabilities must be real time, on-line, and adequately SensiHve for proper system Controis. Their operational
reliability must be over an extremely long time durati0n and must require minimal maintenance. Finally,
elements of a CELSS which will be deployed in free space must have the capability Of operating in a
microgravity environment. : :_- ..... _ .......
Several advan_d technologies required to 015erate-tlie Biomass Production ModuIe of a CELSS have been
identified. Fiber optic sensors for o_line monitoring and control for selected parameters in the BPC are
being developed and tested. Parameters to be measured by the sensors include atmospheric ethylene, trace
organic contaminants, pH, moisture levels, microbial organisms, and specific ions in nutrient delivery solutions.
These sensors use primary and secondary absorbance and liquid atomic emission technologies as their primary
measuring processes. Mos_t ofthe sensors currently available for m_onitor)mg t_hese and other parameters in the
Biomass Production Chamber are not sensitive enough or when on-line require excessive maintenance to keep
them operative. Development of computer software will be required in order to establish expert control of the
atmosphere in the BPC using the outputs from the array of sensors. We have developed some chamber
162
control software along with new data display capability for the BPC during the past two years. Technologies
for the production, transportation, and distribution of irradiance for plant growth is another primary area of
interest to the CELSS program. Current research in this area has concentrated on a light pipe material and
fiber optics for transportation and distribution of the light energy. Of major importance in this technology
area is the increased efficiency of bulbs and the maximum delivery of photons to the plant surface.
At least one project is evaluating noninvasive remote sensing systems that may be useful in detecting water
stress and/or nutrient deficiency in plants. A technology that will detect plant stress prior to it reaching a
level to cause a decrease in productivity is vital to the successful development of a CELSS. Robots with vision
imaging capabilities will be required to locate sensors and conduct plant manipulations such as seeding and
harvesting. A seeding robot for wheat has been developed and tested. The development of robotic
capabilities that will significantly reduce the time required to operate the Plant Production Module is
important. Finally, if the CELSS is to operate in a microgravity environment then a major requirement is to
develop a system to deliver water and nutrients to the roots of plants under these conditions (Wright, et. al.
1988/7/). We have developed and tested a membrane nutrient delivery system(Figure 3) as a potential
technology to accomplish this task (Dreschel and Sager, 1989/8/). Other projected areas requiring technology
development in order to develop a successful Biomass Production Module for a CELSS include genetic plant
engineering, management of tissue culture systems, trace contaminant removal from air and water, and water
collection devices.
Many of the technologies discussed previously for the Biomass Production Module are also required for
the Food Preparation, Biomass Processing, and Resource Recovery Modules. Advance sensor technology and
expert computer control are needed to operate bioreactors that are vital to these modules. The requirements
for these sensors and computer software are identical to or only slightly modified from those discussed for the
Biomass Production Module. New equipment to thrash, mill, and grind edible biomass and to process the
same into food needs to be developed. This equipment must be small, easy to operate, and extremely efficient
so that little, if any, wastage occurs. The aquaculture system will require some advance technologies that have
not been previously discussed. Sensors and controls for the nitrogen wastes produced by the fish must be
developed. Development of a food for the fish using only inedible plant material is a major challenge.
Technologies to reduce the amount of water to support the fish and video systems to monitor the health of the
fish are a few other capabilities which require research. There is no doubt as these processing and resource
recovery modules become more a part of the Breadboard Project, additional advance technologies required to
operate these modules will be identified.
SUMMARY
The CELSS Breadboard Project is proceeding on schedule and a demonstration of feasibility at a one
person scale should be accomplished in the next 3-4 years. The Biomass Production Module is complete and
producing data on plant growth and development, water cycling, and carbon dioxide and oxygen exchange.
During the past 2-3 months, efforts have been initiated to develop the Food Preparation, Biomass Processing,
and Resource Recovery Modules that will complete the initial CELSS Breadboard. In order for a CELSS to
be deployable in space to meet the life support requirements of humans, significant advancement in selected
technologies is required. A few technologies are currently being researched such as fiber optic sensors,
noninvasive remote plant stress sensors, expert computer controls, and mlcrogravity compatible nutrient
delivery systems. Improved sensor sensitivity and reliability, efficient irradiance production and delivery
systems, and expert computer controls must be developed in order to control the physical systems required to
maintain the biology. Technologies to monitor biological stress, to accomplish genetic engineering, and to
provide tissue culture maintenance must be completed prior to the development of an operational CELSS.
The development of advanced technologies are primarily aimed at reduction in energy use, limiting manpower
requirements, miniaturization of subcomponents, improved operation reliability, on-line monitoring capabilities,
and functionality in microgravity. In order for human beings to develop a truly permanent presence in space,
a CELSS must be developed and a significant advancement in technologies is required in order to make such
a life support system possible.
163
..
,
.
°
.
.
.
LITERATURE
Pioneering the Space Frontier. National Commission on Space (The Paine Commission), New York,
Bantam Books, 1986.
Exploring the Universe: A Strategy for Space Life Sciences. (The "Robbins" Report), Life Sciences
Strategic Planning Study Committee, NASA Advisory Council, Washington, D.C.
Koller, A. M.. CELSS Breadboard Facility Project Plan. Biomedical Operations and Research Office.
National Aeronautics & Space Administration, Kennedy Space Center. March 1986.
Prince, R. P. and Knott, W. M.: CELSS Breadboard Project at the Kennedy Space Center. In: D. W.
Ming and D, L. Henninger (eds.), Lunar Base Agriculture; Soils for Plant Growth. Amer. Soc.
Agron., Madison, WI USA. 1989.
Wheeler, R. M. and Sager, J. C.: Carbon Dioxide and water exchange rates by a wheat crop in
NASA's Biomass Production Chamber results from an 86-day study (January to April 1989). NASA
Technical Memorandum. TM 102788. January 1990.
Wheeler, R. M., Mackowaik, C. L., Dreschel, T. W., Sager, J. C., Prince, R. P., Knott, W. M., Hinlde,
C. R. and Strayer, R. F.." System development and early biological tests in NASA's Biomass
Production Chamber. National Aeronautics & Space Administration. Technical Memorandum. TM
103494. March 1990.
Wright, B. D., Bausch, W. C. and Knott, W. M.: A Hydroponic system for microgravity plant
experiments. Trans of the ASAE. 31(2). 440-446. 1988.
Dreschel, T. W. and Sager, J. C.: Control of water and nutrients using porous tube: A method for
growing plants in space. HortScience 24(6): 944-947. 1989.
164
165
0166
I/<7°
! i I
167
kL
SESSION E - MATERIALS SCIENCE (PART 2)
Wednesday November 28, 1990
Silicon Carbide, An Emerging High-Temperature Semiconductor
Flexible Fluoropolymer-Filled Protective Coatings
A Conformal Oxidation-Resistant, Plasma-Polymerized Coating
Flame-Retardant Composite Materials
Superplastic Forming Of AI-Li Alloys For Lightweight, Low-Cost
Structures
Localized Corrosion Of High-Performance Metal Alloys In An Acid/Salt
Environment
PRECEDING PAGE BLANK NOT FILMED
169
, ? -


Monitoring and control technologies for bioregenerative life support systems/CELSS

Abstract

Similar works

Full text

Available Versions

NASA Technical Reports Server