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Future space exploration missions will require a lightweight spacesuit that expends no consumables. This paper describes the design and performance of a prototype heat rejection system that weighs less than current systems and vents zero water. The system uses regenerable LiCl/water absorption cooling. Absorption cooling boosts the heat absorbed from the crew member to a high temperature for rejection to space from a compact, non-venting radiator. The system is regenerated by heating to 100°C for two hours. The system provides refrigeration at 17°C and rejects heat at temperatures greater than 50°C. The overall cooling capacity is over 100 W-hr/kg.

In order to provide effective cooling for astronauts during extravehicular activities (EVAs), a liquid cooling and ventilation garment (LCVG) is used to remove heat by a series of tubes through which cooling water is circulated. To better predict the effectiveness of the LCVG and determine possible modifications to improve performance, computer simulations dealing with the interaction of the cooling garment with the human body have been run using the Wissler Human Thermal Model. Simulations have been conducted to predict the heat removal rate for various liquid cooled garment configurations. The current LCVG uses 48 cooling tubes woven into a fabric with cooling water flowing through the tubes. The purpose of the current project is to decrease the overall weight of the LCVG system. In order to achieve this weight reduction, advances in the garment heat removal rates need to be obtained.

The Waste and Hygiene Compartment will serve as the primary facility for metabolic waste management and personal hygiene on the United States segment of the International Space Station. The Compartment encloses the volume of two standard ISS racks and will be installed into Node 3 after launch inside a Multipurpose Logistics Module on the Space Shuttle. Long duration space flight requires a departure from the established hygiene and waste disposal practices employed on the Space Shuttle. This paper describes requirements and a conceptual design for the Waste and Hygiene Compartment that are both logistically practical and acceptable to the crew.

A new and advanced portable life support system (PLSS) for space suit surface exploration will require a durable, compact, and energy efficient system to transport the ventilation stream through the space suit. Current space suits used by NASA circulate the ventilation stream via a ball-bearing supported centrifugal fan. As NASA enters the design phase for the next generation PLSS, it is necessary to evaluate available technologies to determine what improvements can be made in mass, volume, power, and reliability for a ventilation transport system. Several air movement devices already designed for commercial, military, and space applications are optimized in these areas and could be adapted for EVA use. This paper summarizes the efforts to identify and compare the latest fan and bearing technologies to determine candidates for the next generation PLSS.

Lunar and martian materials can be processed and used at planetary outposts to reduce the need (and thus the cost) of transporting supplies from Earth. A variety of uses for indigenous, on-site materials have been suggested, including uses as rocket propellants, construction materials, and life support materials. Utilization of on-site resources will supplement Regenerative Life Support Systems (RLSS) that will be needed to regenerate air, water, and wastes, and to produce food (e.g., plants) for human consumption during long-duration space missions.

An Advanced Automotive Manikin (ADAM), is used to evaluate liquid cooling garments (LCG) for advanced space suits for extravehicular applications and launch and entry suits. The manikin is controlled by a finite-element physiological model of the human thermoregulatory system. ADAM's thermal response to a baseline LCG was measured.The local effectiveness of the LCG was determined. These new thermal comfort tools permit detailed, repeatable measurements and evaluation of LCGs. Results can extend to other personal protective clothing including HAZMAT suits, nuclear/biological/ chemical protective suits, fire protection suits, etc.

Pretreatment of urine using Oxone® and sulfuric acid is baselined in the International Space Station (ISS) waste water reclamation system to control odors, fix Ammonia and control microbial growth. In addition, pretreatment is recommended for long term flight use of urine collection and two phase separation to reduce or eliminate fouling of the associated hardware and plumbing with urine precipitates. This is important to the ISS application because the amount of maintenance time for cleaning and repairing hardware must be minimized. This paper describes the development of a chemical pretreatment system based on solid tablet shapes which are positioned in the inlet urine collection hose and are dissolved by the entrained urine at the proper ratio of pretreatment to urine. Building upon the prior success of the developed and tested solid Oxone tablet, a trade study and tests were completed to confirm if a similar approach would be appropriate for the sulfuric acid injection method.

Shuttle Extravehicular Mobility Unit (EMU) studies have shown that the thermal interaction between the crewperson, liquid cooling garment and EMU thermal management system is highly transient in nature. Recent investigations of these phenomena provide a better understanding which have helped improve thermal comfort in the present system. Analyses show that the key to thermal comfort is understanding the interaction between physiological responses and EMU system thermal transients. A test program was conducted to evaluate the theorized causes of discomfort and proposed corrective actions. Several EMU thermal management related modifications were utilized in the Hubble Space Telescope repair mission where five, two crewperson ExtraVehicular Activities (EVAs) were conducted without any thermal discomfort in a mildly cold environment.

As planetary suit and planetary life support systems develop, specific design inputs for each system relate to a presently unanswered question concerning operational concepts: What distance can be considered a safe walking distance for a suited crew member exploring the surface of the Moon to ‘walkback’ to the habitat in the event of a rover breakdown, taking into consideration the planned extravehicular activity (EVA) tasks as well as the possible traverse back to the habitat? It has been assumed, based on Apollo program experience, that 10 kilometers (6.2 mi) will be the maximum EVA excursion distance from the lander or habitat to ensure the crew member's safe return to the habitat in the event of a rover failure. To investigate the feasibility of performing a suited 10 km walkback, NASA-JSC assembled a multi-disciplinary team to design and implement the ‘Lunar Walkback Test’.

A porous plate sublimator (an existing Lunar Module design) is being evaluated as the heat sink for the X-38 vehicle due to its simplicity, reliability, and flight readiness. It is ideally suited for the X-38/CRV as it requires no active control, has no moving parts, has 100 % water usage efficiency, and is a well-proven technology. This paper presents sublimator performance, including ground test data at CRV conditions, at both a component and system level. Potential sublimator modifications which could allow significant CRV ECLSS system simplification, reliability enhancement, and cost reduction are also discussed.

A porous plate sublimator (based on an existing Lunar Module LM-209 design) is baselined as a heat rejection device for the X-38 vehicle due to its simplicity, reliability, and flight readiness. The sublimator is a passive device used for rejecting heat to the vacuum of space by sublimating water to obtain efficient heat rejection in excess of 1,000 Btu/lb of water. It is ideally suited for the X-38/CRV mission as it requires no active control, has no moving parts, has 100% water usage efficiency, and is a well-proven technology. Two sublimators have been built and tested for the X-38 program, one of which will fly on the NASA V-201 space flight demonstrator vehicle in 2001. The units satisfied all X-38 requirements with margin and have demonstrated excellent performance. Minor design changes were made to the LM-209 design for improved manufacturability and parts obsolescence.

For over 40 years, NASA has been putting humans safely into space in part by minimizing microbial risks to crew members. Success of the program to minimize such risks has resulted from a combination of engineering and design controls as well as active monitoring of the crew, food, water, hardware, and spacecraft interior. The evolution of engineering and design controls is exemplified by the implementation of HEPA filters for air treatment, antimicrobial surface materials, and the disinfection regimen currently used on board the International Space Station. Data from spaceflight missions confirm the effectiveness of current measures; however, fluctuations in microbial concentrations and trends in contamination events suggest the need for continued diligence in monitoring and evaluation as well as further improvements in engineering systems. The knowledge of microbial controls and monitoring from assessments of past missions will be critical in driving the design of future spacecraft.

As part of its integrated system test bed capability, NASA's Advanced Life Support Program has undertaken the development of a large-scale advanced life support facility capable of supporting long-duration testing of integrated, regenerative biological and physicochemical life support systems. This facility--the Advanced Life Support Human-Rated Test Facility (HRTF) is currently being built at the Johnson Space Center. The HRTF is comprised of a series of interconnected chambers with a sealed internal environment capable of supporting a test crew of four for periods exceeding one year. The life support system will consist of both biological and physicochemical components and will perform air revitalization, water recovery, food production, solid waste processing, thermal management, and integrated command and control functions. Currently, a portion of this multichamber facility has been constructed and is being outfitted with basic utilities and infrastructure.

The most recent goal of our research program was to identify the optimal features of each of three garments to maintain core temperature and comfort under intensive physical exertion. Four males and 2 females between the ages of 22 and 46 participated in this study. The garments evaluated were the MACS-Delphi, Russian Orlan, and NASA LCVG. Subjects were tested on different days in 2 different environmental chamber temperature/humidity conditions (24°C/H∼28%; 35°C/H∼20%). Each session consisted of stages of treadmill walking/running (250W to 700W at different stages) and rest. In general, the findings showed few consistent differences among the garments. The MACS-Delphi was better able to maintain subjects within a skin and core temperature comfort zone than was evident in the other garments as indicated by a lesser fluctuation in temperatures across physical exertion levels.

Hamilton Sundstrand has developed a scalable evaporative heat rejection system called the Multi-Fluid Evaporator (MFE). It was designed to support the Orion Crew Module and to support future Constellation missions. The MFE would be used from Earth sea level conditions to the vacuum of space. This system combines the functions of the Space Shuttle flash evaporator and ammonia boiler into a single compact package with improved freeze-up protection. The heat exchanger core is designed so that radial flow of the evaporant provides increasing surface area to keep the back pressure low. The multiple layer construction of the core allows for efficient scale up to the desired heat rejection rate. A full-scale unit uses multiple core sections that, combined with a novel control scheme, manage the risk of freezing the heat exchanger cores. A four-core MFE prototype was built in 2007.

Long-duration missions in space will require regenerative air revitalization processes. Human testing of these regenerative processes is necessary to provide focus to the system development process and to provide realistic metabolic and hygiene inputs. To this end, the Lyndon B. Johnson Space Center (JSC), under the sponsorship of NASA Headquarters Office of Life and Microgravity Sciences and Applications, is implementing an Early Human Testing (EHT) Project. As part of this project, an integrated physicochemical Air Revitalization System (ARS) is being developed and tested in JSC's Life Support Systems Integration Facility (LSSIF). The components of the ARS include a Four-Bed Molecular Sieve (4BMS) Subsystem for carbon dioxide (CO2) removal, a Sabatier CO2 Reduction Subsystem (CRS), and a Solid Polymer Electrolyte (SPE)™ Oxygen Generation Subsystem (OGS). A Trace Contaminant Control Subsystem (TCCS) will be incorporated at a later date.

In a crewed spacecraft environment, atmospheric carbon dioxide (CO2) and moisture control are crucial. Hamilton Sundstrand has developed a stable and efficient amine-based CO2 and water vapor sorbent, SA9T, that is well suited for use in a spacecraft environment. The sorbent is efficiently packaged in pressure-swing regenerable beds that are thermally linked to improve removal efficiency and minimize vehicle thermal loads. Flows are all controlled with a single spool valve. This technology has been baselined for the new Orion spacecraft. However, more data was needed on the operational characteristics of the package in a simulated spacecraft environment. A unit was therefore tested with simulated metabolic loads in a closed chamber at Johnson Space Center during the last third of 2006. Tests were run at a variety of cabin temperatures and with a range of operating conditions varying cycle time, vacuum pressure, air flow rate, and crew activity levels.

Hamilton Standard Space Systems International, Inc. (HSSSI) has obtained and is currently testing a variety of Russian life support hardware. These units have been or are contemplated for use on Mir I and II space stations. This paper presents the current status of performance testing of a Sabatier Carbon Dioxide Processing Unit (CDPU) and components of a Potable Water Processing System (PWP). These systems were fabricated by NIICHIMMASH, the supplier of these units to the Russian space program. It is the intent of this testing program to obtain a data base for technology comparisons to support planned and future international missions. For the CDPU, reactant conversion efficiencies in excess of 99 percent have been noted for the variation in test conditions with 2 to 6 man processing (flows) tested. The CDPU's effluent water has been produced at anticipated rates and is relatively contaminant free.

The TIMES is an evaporative water processor which has shown great theoretical potential for providing reliable and efficient production of high quality water. The test results of the system have however fallen short of the predicted performances. A thorough systems analysis has identified the condensing heat exchanger as a primary source of the shortcomings of the assembly. This condenser, along with three other heat exchangers in the system, have been redesigned and integrated into a new “Regenerator” that is predicted to significantly lower the power consumption and improve both the operating stability and product water quality.

The Advanced Integration Matrix (AIM) project at the Johnson Space Center (JSC) was chartered to study and solve systems-level integration issues for exploration missions. One of the first issues identified was an inability to conduct trade studies on control system architectures due to the absence of mature evaluation criteria. Such architectures are necessary to enable integration of regenerative life support systems. A team was formed to address issues concerning software and hardware architectures and system controls.. The team has investigated what is required to integrate controls for the types of non-linear dynamic systems encountered in advanced life support. To this end, a water processing bioreactor testbed is being developed which will enable prototyping and testing of integration strategies and technologies.