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BioSim is a simulation tool which captures many basic life support functions in an integrated simulation. Conventional analyses can not efficiently consider all possible life support system configurations. Heuristic approaches are a possible alternative. In an effort to demonstrate efficacy, a validating experiment was designed to compare the configurational optima discovered by heuristic approaches and an analytical approach. Thus far, it is clear that a genetic algorithm finds reasonable optima, although an improved fitness function is required. Further, despite a tight analytical fit to data, optimization produces disparate results which will require further validation.

Future long-term space missions, such as a manned mission to Mars, will require regenerative life support systems which will enable crews more self-sufficiency and less dependence on resupply. Toward this effort, a series of tests called the Lunar-Mars Life Support Test Project have been conducted as part of the National Aeronautical and Space Administration (NASA's) advanced life support technology development program. The last test in this series was the Phase III test which was conducted September 19 - December 19, 1997 in the Life Support Systems Integration Facility at the Johnson Space Center. The overall objective of the Phase III test was to conduct a 90-day regenerative life support system test with four human test subjects demonstrating an integrated biological and physicochemical life support system to produce potable water, maintain a breathable atmosphere, and maintain a shirt sleeve environment.

During Lunar missions, NASA's new Orion Crew Exploration Vehicle (CEV) may benefit from mass savings and increased reliability by the use of a passive, capillary-driven Static Phase Separator (SPS) for urine collection, containment, and disposal in place of a rotary-fan separator and wastewater storage tank. The design of a capillary separator addresses unique challenges for microgravity fluid management for liquids with a wide range of possible contact angles and high air-to-liquid flow ratio. This paper presents the iterative process leading to a successful test in a reduced gravity aircraft of the SPS concept. Using appropriately scaled test conditions, the resulting prototype allows for a range of wetting properties with complete separation of liquid from gas.

Two portable, collapsible water storage containers were developed to enable water logistics and storage on ISS. The first is a new version of the 44-liter Contingency Water Container (CWC) originally developed for the Shuttle Program. The new CWC uses a thicker Combitherm® film, VPCXX 140, as the bladder material. The second is a multipurpose 10-liter vessel, known as the Payload Water Reservoir (PWR), with a Teflon® bladder. Both of these collapsible vessels have Nomex® outer restraints for structural support, allowing them to withstand pressurization and resist puncture. The results of material longevity tests, the design and development of the two containers are briefly reported, and current and future water, wastewater, coolant and experiment fluid storage applications for the ISS are described.

The BIO-Plex is a key component in the testing capability of NASA’s Advanced Life Support (ALS) Program. BIO-Plex will serve as a test facility capable of supporting long duration evaluations of integrated systems that produce food, purify water, regenerate oxygen, and supply clean air to human test crews. The major test facility is comprised of a set of interconnected chambers with a sealed internal environment, which will be capable of supporting test crews of four individuals for periods exceeding one year. In this tightly controlled, closed loop system, hypogravity compatible life support systems for use on planetary surfaces such as Mars or the Moon will be evaluated during long duration tests with human subjects inside the BIO-Plex at Johnson Space Center (JSC).

The first two phases of the Lunar-Mars Life Support Test Project [LMLSTP] involved housing human volunteers in closed chambers that mimic future extraterrestrial life support systems. The Phase I test involved one person living for 15 days in a chamber with wheat as the primary means of air revitalization. The Phase II test involved 4 people living for 30 days in a chamber with physical/chemical air revitalization and waste water recycling. The consequences of closure on microbial ecology and the influence that microbes had on these closed environmental life support systems were determined during both tests. The air, water, and surfaces of each chamber were sampled for microbial content before, during, and after each test. The numbers of microbes on the Phase I habitation chamber surfaces increased with length of occupation.

An important milestone in the ongoing effort by NASA to develop and refine closed-loop water recycling systems for human space flight was reached during the summer of 1996 with the successful completion of Phase II of the Lunar Mars Life Support Testing Program at Johnson Space Center. Part of Phase II involved testing a water-recycling system in a closed test chamber continuously occupied by four human subjects for thirty days. The Phase II crew began the test with a supply of water that had been processed and certified for human use. As the test progressed, humidity condensate, urine, and wastewater from personal hygiene and housekeeping activities were reclaimed and reused several times. Samples were collected from various points in the reclamation process during the thirty day test. The data verified the water-processing hardware can reliably remove wastewater contaminants and produce reclaimed water that meets NASA standards for hygiene- and potable-quality water.

An 84 day wheat crop was grown in the Variable Pressure Growth Chamber (VPGC) at Johnson Space Center (JSC). The VPGC is an atmospherically closed, controlled environment facility used to evaluate the use of higher plants as part of a regenerative life support system. The chamber has 10.6 m2 of growing area consisting of 480 pots of calcined clay support media. The chamber is lit by very high output, cool white fluorescent bulbs. Five wheat seeds were planted per pot giving a seeding density of 227 seeds·m-2. Pots were irrigated with a modified half strength Hoagland's nutrient solution three or six times per day depending on the crop age. At the plant canopy, the average temperature during the test was 22 ° C, relative humidity was maintained at 69%, CO2 concentration was 1000 ppm, photoperiod was continuous light, and the light intensity averaged 350 μmol·m-2·s-1.

A computer interfaced instrument designed to quantify ammonia and other nitrogenous species that are important regenerative life support water quality parameters is described in this paper. Measurements can be made either discretely by Flow Injection Analysis (FIA) or continuously using a split stream from a process flow. The monitor exhibits a predictable quadratic response for ammonia injections between 10 μg/L to 20 mg/L with a response time less than six minutes. A full description of the ammonia monitor's response to a variety of challenge solutions including real sewage treatment plant effluent is given. In addition, the response time characteristics, the effects of temperature, and interferences are described.

In preparation for future planetary exploration, NASA-Johnson Space Center has developed a critical path plan for food and nutrition research needs. The plan highlights the risk factors pertaining to food and nutrition associated with exposure to the space flight environment as well as the possible consequences if no corrective measures are implemented. Included in the plan are the initiating events such as microgravity, remote environment and mission duration, which obviously impact the risk factors. The plan includes points of intervention where mitigating factors can be implemented to avoid outcomes such as malnutrition and unsafe foods. Physiological changes induced by lack of gravity, as well as increased exposure to radiation, may alter nutrient bio-availability and/or nutrient requirements. An inadequate food system, whether due to technical limitations or nutritional shortcomings, can result in serious consequences.

Ground-based laboratory and closed-chamber human tests have demonstrated the ability of microbial-based biological processors to effectively remove carbon and nitrogen species from regenerable life support wastewater streams. Application of this technology to crewed spacecraft requires the development of gravity-independent bioprocessors due to a lack of buoyancy-driven convection and sedimentation in microgravity. This paper reports on the development and testing of membranebased biological reactors and addresses the processing of planetary and International Space Station (ISS) waste streams. The membranes provide phase separation between the wastewater and metabolically required oxygen, accommodate diffusion-driven oxygen transport, and provide surface area for microbial biofilm attachment. Testing of prototype membrane bioprocessors has been completed.

As a key component in its ground test bed capability, NASA’s Advanced Life Support Program has been developing a large-scale advanced life support test facility capable of supporting long-duration evaluations of integrated bioregenerative life support systems with human test crews. This facility-targeted for evaluation of hypogravity compatible life support systems to be developed for use on planetary surfaces such as Mars or the Moon-is called the Bioregenerative Planetary Life Support Systems Test Complex (BIO-Plex) and is currently under development at the Johnson Space Center. This test bed is comprised of a set of interconnected chambers with a sealed internal environment which are outfitted with systems capable of supporting test crews of four individuals for periods exceeding one year. The advanced technology systems to be tested will consist of both biological and physicochemical components and will perform all required crew life support functions.