THE CLOSED LIFE-SUPPORT SYSTEM NASA SP-134 THE CLOSED LIFE-SUPPORT SYSTEM Ames Research Center M of f ett FieId, Culiforn ia April 14-15, 1966 prepared by Ames Research Center Scient+ and Tecbnical Information Division OFFICE OF TECHNOLOGY UTILIZATION 1967 NATIONAL AERONAUTICS AND SPACE ADMINISTRATION Washington, D.C. FOREWORD Scientists and engineers have been concerned for many years with the challenging problems inherent in the fabrication of a closed life-support sys- tem. Aside fromthe prospects of difficult engineering hurdles yet to be overcome, it is also clear that enormous gaps exist in our fundamental knowl- edge about many aspects of this problem. For example, it is impossible at this time even to summarize man's nutritional requirements completely! Virtually nothing is known about human production of contaminants and not much more is available regarding man's tolerance levels to such materials. Biological agents that might be employed to convert human wastes to useful foodstuffs or fuels are themselves incompletely studied, particularly from I1 the' point of view of their usefulness as potential chemosynthesizers .If On the other hand, physicochemical procedures to accomplish these end results have barely been initiated. This Conference, then, is an attempt to examine the present status of some of these problems. Hopefully, lines of future research and development will become clearer as a result of these deliberations and, if this leads to more vigorous and more rigorous experimentation and study, the Conference 2-Y.l surely have been successful. HAROLD P. XLEIN Assistant Director for Life Sciences iii CONTENTS Page STUDY OF LIFE-SUPPORT SYSTEMS FOR SPACE MISSIONS EXCEEDING ONE YEAR INDURATION ............................. 1 G. L. Drake, C. D. King, W. A. Johnson, and E. A. Zuraw General Dynamic s /Conva ir Divi sion STUDY OF LIFE-SUPPORT SYSTEMS FOR SPACE MISSIONS EXCEEDING ONE YEAR INDURATION............ ................. 75 R. B. Jagow and R. S. Thomas, Editors Lockheed Missiles and Space Company, Sunnyvale, Calif PUNS FOR A PROGRAM TO STUDY CLOSED LIFE-SUPPORT SYSTEMS ........ 145 E. Gene Lyman Ames Research Center WASTE STABILIZATION IN SPACE ENVIRONMENTS ............... 151 H. G. Schwartz, Jr., and J. E. McKee 3 W. M. Keck Laboratory of Environmental Health Engineering, California Institute of Technology THE SPIN-INERTIA CUEI'URE SYSTEM IN WASTE TREATMENT IN CLOSED SYSTEMS . 163 Clarence G. Golueke and William J. Oswald Sanitary Engineering Research Laboratory, College of Engineering and School of Public Health, University of California, Berkeley DESIGN AND EVALUATION OF CHEMICALLY SYNTHESIZED FOOD FOR LONG SPACE MISSIONS .............................. 175 Jacob Shapira Ames Research Center PROSPECTUS FOR CHEMICAL SYNTHESIS OF PROTEINACEOUS FOODSTUFFS ..... 189 Sidney W. Fox Institute of Molecular Evolution, University of Miami THE EFFECTS OF CONTR0LI;ED ENVIRONMENT ON THE GROWTH OF HYDROGENOMONAS BACTERIA IN CONTINUOUS CULTURES ................... 201 John F. Foster and John H. Litchfield Battelle Memorial Institute, Columbus Laboratories ALGAL SYSTEMS FOR BIOLOGICAL FOOD SYNTHESIS .............. 213 C. H. Ward, Rice University, and R. L. Miller, USAF School of Aero space Medicine APPENDIX: ATTENDEES AT THE CONFERENCE . - . * . * 225 STUDY OF LIFE-SUPPORT SYSTEMS FOR SPACE MISSIONS EXCEEDING ONE YEAR IN DURATION By G. L. Drake, C. D. King, W. A. Johnson, and E. A. Zuraw General Dynamics Convair Division IIYI'RODUCT ION This Phase I study is a step toward the goal of providing a closed ecol- ogy for manned space missions of long duration. Life support are needed that will operate for periods exceeding one year without resupply. An essential requirement will be the ability to convert human and cabin waste products into useful products such as oxygen, food, and potable water. There is already substantial progress in the closure of the oxygen and water loops (ref. 1) and it is expected that this progress will continue to the point of flight-ready hardware for long-duration missions. Closure of the food-waste loop is cony siderably less advanced. Therefore, study emphasis was placed on this food- waste closure while work on other life-support subsystems was directed primarily at insuring integration compatibility. Purpose The purpose of this study is to verify technical justification and provide planning direction for subsequent phases of the program, namely, Phase 11, Research and Development; Phase 111, Engineering Design; Phase IV, Construction of a Prototype Closed Ecological System; and Phase V, Evaluation of the Prototype Closed Ecological System. In accordance with this purpose, tasks were performed as follows : (1) The state of development of life support subsystems was reviewed; (2) configurations of closed ecological systems were established; (3) preferred systems were selected, based on estimates of engineering and biological practicality; (4) requirements for research and development to qualify the systems for engineering design were identified; (5) priorities were established and specifications were written for the research and development; and (6) a program plan was prepared for the remaining phases of the program. Scope This report summarizes the accomplishments of the first four tasks listed above. Consideration was given to all reasonably applicable concepts for food-waste loop closure within the constraints of space mission use. They were evaluated to a degree of detail commensurate with the fund of technical information. The subsystems were categorized as "biological" and "physico- chemical," and were further divided into those having primarily a food synthesis function and those having waste processing functions. 1 Biosystems. - The data available on some biological subsystems were suffi- cient to estimate engineering parameters. These were biosystems based on algae, hydrogen bacteria, higher plants, yeast molds, activated sludge, or anaerobic sludge. The limited data available concerning many other proposed biosystems did not permit evaluations to the same level of detail. The evalu- ations that could be made did not disclose a preponderance of advantages over those biosystems listed. Physicochemical subsystems. - Seven different dombinations of the steps for the synthesis of carbohydrates from CO2 and water were studied, and engineering estimates were derived for the two methods for which some process data was available. The chemical synthesis of fats and protein derivatives was reviewed. Waste processes studied included the recovery of potable water from liquid and solid wastes and the oxidation of solid residues. Method Technical information was assembled from many sources, including tech- nical literature and government, educational, and industrial organizations. These sources provided information of processes components, analyses, and egperimental results, so that the merit of closed ecology could be evaluated. Configurations of the complete closed food-waste loop and supporting sub- systems were then developed from competitive subsystems. Engineering param- eters were calculated from the reported research data. In many cases, engineering estimates were based on extrapolations from known characteristics of existing systems. The closed configurations selected indicate the preferred channel for subsequent researcn and development. SYSTEM MODEL A spacecraft system model was established to provide ground rules and a suitable frame of reference for evaluating subsystems and the closed config- urations. It is solely a tool to help achieve an orderly evaluation, and is not intended or applied in a manner to exclude consideration of any valid concepts. The system model is based on studies of manned planetary missions (ref. 2), and its elements are a mission model, a spacecraft model, a crew model, and a basic performance model for the life support system. Portions that were particularly significant to the evaluations are presented in the following paragraphs. Mission Model Mission: Earth-Mars round trip with Mars orbit capture, in support of landing by other vehicles. Mission periods: Earth orbit to Mars orbit 230 days Planetary capt ure 50 days Mars orbit to Earth orbit 260 days Total 540 days Orbit altitudes: Earth 325 km Mars 1000 km 2 Gravity environment : Extended periods of weightlessness Solar orientation: Random Spacecraft Model Physical configuration: Four cylindrical compartments, with inter- connection or isolation capabilities. Dimensions of each compartment: Diameter 20 ft (6.10 m) Height 8 ft (2.44 m) Cabin atmosphere quantities: Volume, total of four compartments 10,000 ft3 (283 m3) Leakage rate 0 Electrical power supply : Capacity, normal mode 60 kW c Capacity, emergency mode 10 kW Power type: 28 VDC and 3-phase ac, 115-208 V, 400 cps Weight penalty 50 kg/kW Thermal control: Heat rejection Type: Liquid transport to space radiator integral with spacecraft Temperatures: Radiator inlet, max. 75,0 C Radiator outlet oc Weight penalty 15 kg/kW Process heat Type: Liquid transport from a waste heat source in power system Temperatures : Supply 200: c Return 100 c Weight penalty 1-5 kg/kW Crew Model Number and distribution: Ten men, with normally no more than four in any compartment. Metabolic criteria, daily averages, per man-day (crew average activity at 150 percent BMR): O2 uptake, g 850 co;2 output, g 1000 Water of oxidation, g 315 Water allowance, g 3 500 Urine water, g 1500 maporat ive water loss (respiration and perspiration), g 2200 Latent heat, kg -ea1 1080 Sensible heat,