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Biological wastewater processing has been under investigation by AlliedSignal Aerospace and NASA Johnson Space Center (JSC) for future use in space. Testing at JSC in the Hybrid Regenerative Water Recovery System (HRWRS) in preparation for future closed human testing has been performed. Computer models have been developed to aid in the design of a new four-person immobilized cell bioreactor. The design of the reactor and validation of the computer model is presented. In addition, the total organic carbon (TOC) computer model has been expanded to begin investigation of nitrification. This model is being developed to identify the key parameters of the nitrification process, and to improve the design and operating conditions of nitrifying bioreactors. In addition, the model can be used as a design tool to rapidly predict the effects of changes in operational conditions and reactor design, significantly reducing the number and duration of experiments required.

Two crops of lettuce (Lactuca sativa cv. Waldmann's Green) were grown in the Regenerative Life Support Systems (RLSS) Test Bed at NASA's Johnson Space Center. The RLSS Test Bed is an atmospherically closed, controlled environment facility for the evaluation of regenerative life support systems using higher plants. The chamber encloses 10.6 m2 of growth area under cool-white fluorescent lamps. Lettuce was double seeded in 480 pots, each containing about 250 cm3 of calcined-clay substrate. Each pot was irrigated with half-strength Hoagland's nutrient solution at an average total applied amount of 2.5 and 1.8 liters pot-1, respectively, over each of the two 30-day crop tests. Average environmental and cultural conditions during both tests were 23°C air temperature, 72% relative humidity, 1000 ppm carbon dioxide (CO2), 16h light/8h dark photoperiod, and 356 μmol m-2s-1 photosynthetic photon flux.

Procedures for rapid microbiological analysis were performed during simulated surface extra-vehicular activity (EVA) at Meteor Crater, Arizona. The fully suited operator swabbed rock (‘unknown’ sample), spacesuit glove (contamination control) and air (negative control). Each swab sample was analyzed for lipopolysaccharide (LPS) and β-1, 3-glucan within 10 minutes by the handheld LOCAD PTS instrument, scheduled for flight to ISS on space shuttle STS-116. This simulated a rapid and preliminary ‘life detection’ test (with contamination control) that a human could perform on Mars. Eight techniques were also evaluated for their ability to clean and remove LPS and β-1, 3-glucan from five surface materials of the EVA Mobility Unit (EMU). While chemical/mechanical techniques were effective at cleaning smooth surfaces (e.g. RTV silicon), they were less so with porous fabrics (e.g. TMG gauntlet).

When a permanent human outpost is established on the Moon, various methods may be used to reject the heat generated by the base. One proposed concept is the use of a heat pump operating with a vertical, flow-through thermal radiator mounted on a Space Station type habitation module [1]. Since the temperature of the lunar surface varies over the day, the vertical radiator sink temperatures can reach much higher levels than the comfort and even survivability requirements of a habitation module. A high temperature lift heat pump will not only maintain a comfortable habitation module temperature, but will also decrease the size of the radiators needed to reject the waste heat. Thus, the heat pump will also decrease the mass of the entire thermal system. Engineers at the Johnson Space Center (JSC) have tested a High Lift Heat Pump design and are developing the next generation heat pump based on information and experience gained from this testing.

Research indicates that adaptation to a microgravity environment includes physiological changes to the cardiovascular-respiratory, musculoskeletal, and neurosensory systems. Many of these alterations emerge even during space flights of short duration. Therefore, the advancement of manned space flight from Shuttle to Space Station Freedom (SSF) requires development of effective methods for augmenting the ability of humans to maintain functional performance. Thus, it is the goal of NASA to minimize the consequences of microgravity-induced deconditioning to provide optimal in-flight performance (intra- and extra-vehicular activities), suitable return to a pedestrian environment, and nominal physiological postflight recovery for an expeditious return-to-flight physical status.

Developing advanced technology through the prototype phase on a system as complex as a Portable Life Support Subsystem (PLSS) for an Extravehicular Mobility Unit (EMU) is a time and resource consuming process. Experience has shown that most of the decisions controlling the life cycle cost of a system intended for operational use are made very early in the design process. By the preliminary design review most of the design-controlled cost drivers are locked into the design. To ensure a reasonable chance for the design to successfully meet mission requirements, it is best to choose the most promising, most likely-to-succeed technology available in the early stages of breadboard and preprototype development.

Vibrational disturbance magnitude and frequency on space-flight missions is often a critical factor regarding mission success. Both materials processing experiments and astronomical investigations have specific microgravity environmental requirements. Recent efforts have been made to quantify the microgravity environment on the Space Shuttle Columbia by measuring gravity levels produced by specific mission events such as Orbiter engine burns, treadmill and ergometer activities, crew sleep periods, rotating chair operations, and body mass measurement operations. However, no measurements have been made of specific, nominal crewmember activities such as translating about the middeck, flight-deck, or in the Spacelab. This report presents pilot-study data of test subject forces induced by intravehicular activities such as push-offs and landings with both hands and feet. Five subjects participated in this investigation.

To date, 59 man-EVA's have been conducted in the Shuttle Program with minimum physiological problems or limitations. The physiological requirements for life support in the Shuttle EVA include pressure, gas composition, inspired CO2 pressure, heat- removal capability, in-suit water replacement, and caloric replacement. These requirements and their basis in verification testing or analysis are reviewed. The operational measures are identified. The suit pressure in combination with a gas composition of at least 92 percent assures that sufficient O2 pressure is available to the crewmember. The nominal suit pressure of 4.3 psi±0.1 psi was maintained during all 59 man-EVA's. The contingency suit pressure was never required to be used. The suit pressure in combination with the cabin pressure and pre-EVA denitrogenation procedures minimize the risk of altitude decompression sickness. There has been no incidence of decompression sickness during Shuttle EVA.

Since the early 1980’s, the Shuttle Extra Vehicular Activity (EVA) glove design has evolved to meet the challenge of space based tasks. These tasks have typically been satellite retrieval and repair or EVA based flight experiments. With the start of the International Space Station (ISS) assembly, the number of EVA based missions is increasing far beyond what has been required in the past; this has commonly been referred to as the “Wall of EVA’s”. To meet this challenge, it was determined that the evolution of the current glove design would not meet future mission objectives. Instead, a revolution in glove design was needed to create a high performance tool that would effectively increase crewmember mission efficiency. The results of this effort have led to the design, certification and implementation of the Phase VI EVA glove into the Shuttle flight program.

The recovery of potable water from waste water produced by humans in regenerative life support systems is essential for success of long-duration space missions. The Lunar-Mars Life Support Test Project (LMLSTP) Phase II test was performed to validate candidate technologies to support these missions. The test was conducted in the Crew and Thermal Systems Division (CTSD) Life Support Systems Integration Facility (LSSIF) at Johnson Space Center (JSC). Discussed in this paper are the water recovery system (WRS) results of this test. A crew of 4-persons participated in the test and lived in the LSSIF chamber for a duration of 30-days from June 12 to July 12, 1996. The crew had accommodations for personal hygiene, the air was regenerated for reuse, and the waste water was processed to potable and hygiene quality for reuse by the crew during this period. The waste water consisted of shower, laundry, handwash, urine and humidity condensate.

The projections of increased Extravehicular Activity (EVA) operations for the Space Station Freedom (SSF) resulted in the development of advanced space suit technologies to increase EVA efficiency. To eliminate the overhead of denitrogenation, candidate higher-operating pressure suit technologies were developed. The AX-5 all metallic, multi-bearing technologies were developed at the Ames Research Center, and the Mk. III fabric and metallic technologies were developed at the Johnson Space Center. Following initial technology development, extensive tests and analyses were performed to evaluate all aspects of candidate technology performance. The current Space Shuttle space suit technologies were used as a baseline for evaluating those of the AX-5 and Mk. III. Tests included manned evaluations in the Weightless Environment Training Facility and KC-135 zero-gravity aircraft.

Providing water necessary to maintain life support has been accomplished in spacecraft vehicles for over forty years. This paper will investigate how previous U.S. space vehicles provided potable water. The water source for the spacecraft, biocide used to preserve the water on-orbit, water stowage methodology, materials, pumping mechanisms, on-orbit water requirements, and water temperature requirements will be discussed. Where available, the hardware used to provide the water and the general function of that hardware will also be detailed. The Crew Exploration Vehicle (CEV or Orion) water systems will be generically discussed to provide a glimpse of how similar they are to water systems in previous vehicles. Conclusions, questions, and recommendations on strategies that could be applied to CEV based on previous spacecraft water system lessons learned will be made.

NASA's Constellation Program includes the Orion, Altair, and Lunar Surface Systems (LSS) project offices. The first two elements, Orion and Altair, are manned space vehicles while the third element is broader and includes several subelements including Rovers and a Lunar Habitat. The upcoming planned missions involving these systems and vehicles include several risks and design challenges. Due to the unique thermal environment, many of these risks and challenges are associated with the vehicles' thermal control system. NASA's Exploration Systems Mission Directorate (ESMD) includes the Exploration Technology Development Program (ETDP). ETDP consists of several technology development projects. The project chartered with mitigating the aforementioned risks and design challenges is the Thermal Control System Development for Exploration Project.

Long duration NASA-Mir program missions, and the planned International Space Station missions, have given impetus for NASA to implement an operational program of psychological preparation, monitoring, and support for its crews. For exploration missions measured in years, the importance of psychological issues increases exponentially beyond what is currently done. Psychologists' role should begin during the vehicle design and crew selection phases. Extensive preflight preparation must focus on individual and team adaptation, and leadership. Factors such as lack of resupply options and communication delays will alter in-flight monitoring and support capabilities, and require a more self-sufficient crew. Involvement in postflight recovery will also be necessry to ensure appropriate reintegration to the family and job.

Reversible adsorption on zeolite molecular sieve material allows selective removal of carbon dioxide (CO2) from spacecraft air without the use of expendables. The four-bed molecular sieve (4BMS) CO2 removal subsystem chosen for use on space station is based on proven Skylab technology and provides continuous CO2 removal from the cabin atmosphere and concentration for further processing downstream or venting overboard. A 4BMS subsystem has also been chosen to remove CO2 from air in the Systems Integration Research Facility (SIRF) at NASA/Johnson Space Center (JSC). After installation in the SIRF in 1992, the subsystem underwent extensive testing in which cycle time, process air flow rate, and process air inlet CO2 composition were varied. In order to obtain performance data required for integration, the subsystem was operated under both nominal and off-nominal conditions. Results of this testing are presented.

The International Space Station (ISS) program is nearing an assembly complete configuration with the addition of the final resource node module in early 2010. The Node 3 module will provide critical functionality in support of permanent long duration crews aboard ISS. The new module will permanently house the regenerative Environment Control and Life Support Systems (ECLSS) and will also provide important habitability functions such as waste management and exercise facilities. The ISS program has selected the Port side of the Node 1 “Unity” module as the permanent location for Node 3 which will necessitate architecture changes to provide the required interfaces. The USOS ECLSS fluid and ventilation systems, Internal Thermal Control Systems, and Avionics Systems require significant modifications in order to support Node 3 interfaces at the Node 1 Port location since it was not initially designed for that configuration.

One of the risks associated with long-term space flights is cancer incidence resulting from chronic exposure to space radiation. Assessment of incurred risk from radiation exposure requires quantifying the dose throughout the body. The space radiation exposure received by Space Shuttle astronauts is measured by thermoluminescent dosimeters (TLDs) worn during every mission. These dosimeters measure the absorbed dose to the skin, but the dose to internal organs is required for estimating the cancer risk induced by space radiation. A method to extrapolate these skin dose measurements to realistic organ specific dose estimates, using the Computerized Anatomical Man (CAM) and Computerized Anatomical Female (CAF) models, is discussed in detail. A transport code, which propagates high energy nucleon and charged particles, is combined with the CAM/CAF-generated shielding areal distributions to evaluate the absorbed dose at selected organ sites.

The International Space Station Carbon Dioxide Removal Assembly (CDRA) uses regenerable adsorption technology to remove carbon dioxide (CO2) from cabin air. CO2 product water vapor measurements from a CDRA test bed unit at the NASA Marshall Space Flight Center were made using a tunable infrared diode laser differential absorption spectrometer (TILDAS) provided by NASA Glenn Research Center. The TILDAS instrument exceeded all the test specifications, including sensitivity, dynamic range, time response, and unattended operation. During the CO2 desorption phase, water vapor concentrations as low as 5 ppmv were observed near the peak of CO2 evolution, rising to levels of ∼40 ppmv at the end of a cycle. Periods of high water concentration (>100 ppmv) were detected and shown to be caused by an experimental artifact.

An integrated water recovery system was operated for 91 days in support of the Lunar Mars Life Support Test Project (LMLSTP) Phase III test. The system combined both biological and physical-chemical processes to treat a combined wastewater stream consisting of waste hygiene water, urine, and humidity condensate. Biological processes were used for primary degradation of organic material as well as for nitrification of ammonium in the wastewater. Physical-chemical systems removed inorganic salts from the water and provided post-treatment. The integrated system provided potable water to the crew throughout the test. This paper describes the water recovery system and reviews the performance of the system during the test.

NASA's Constellation Program, which includes the mission objectives of establishing a permanently-manned lunar Outpost, and the exploration of Mars, poses new and unique challenges for human life support systems that will require solutions beyond the Shuttle and International Space Station state of the art systems. In particular, the requirement to support crews for extended durations at the lunar outpost with limited resource resupply capability will require closed-loop regenerative life support systems with minimal expendables. Planetary environmental conditions such as lunar dust and extreme temperatures, as well as the capability to support frequent and extended-duration Extra-vehicular Activity's (EVA's) will be particularly challenging.