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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.

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.

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.

A two-stage steam gasification and reforming process was evaluated for converting wastes generated within enclosed habitable environments into synthesis gas (CO & H2) and other recyclable inorganic species, i.e. water, CO2 and inorganic salts. Waste compounds used in the experimentation included: cellulose; urea; methionine; sucrose; butyric acid; Igepon TC-42 - a particularly (chemically) stable soap selected by NASA for use in space life support systems; wheat straw and a high density polyethylene. The compounds were tested individually and in combination to simulate the wastes anticipated within enclosed habitat environments.

A distributed avionics air architecture provides air cooling and air circulation in non-habitable Space Station zones utilizing dedicated hardware to support the zone-specific needs. That dedicated hardware, the Avionics Air Assembly (AAA), includes a selectable speed fan and heat exchanger used in racks for active avionics air cooling to reject the airborne heat load directly to the moderate temperature Internal Thermal Control System (ITCS). This paper addresses the design impacts resulting from the International Space Station Alpha (ISSA) restructure effort. It defines the service provided by the avionics air assembly, the design requirements and the integrated system performance. Detailed package configuration and interfaces, hardware design and off-design performance are included to define the full range of operating capability.

The reproductive ontogeny of ‘Super-Dwarf’ wheat grown on the space station Mir is chronicled from the vegetative phase through flower' development. Changes in the apical meristem associated with transition from the vegetative plhase to floral initiation and development of the reproductive spike were all typical of ‘Super Dwarf’ wheat up to the point of anthesis. Filament elongation, which characteristically occurs just prior to anthesis (during floral development stage 4) and moves the anthers through the stigmatic branches thus facilitating pollination, did not occur in the flowers of spikes grown on Mir. While pollen did form in the anthers, no evidence of pollination or fertilization was observed. Analysis of pollen idlentified abnormalities; the presence of only one nucleus in the pollen as opposed to the normal trinucleate condition is likely an important factor in the sterility observed in wheat grown on Mir.

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).

A three country effort (U.S., Russia, and Bulgaria) has upgraded the plant growth facilities on the Mir Space Station and used the new facility to grow wheat for 90 days. The Svet plant-growth facility was reactivated and used in an initial experiment as part of the Shuttle/Mir program, August to November, 1995. The Svet system, used first to grow cabbage and radish during a 1990 experiment, was augmented by the addition of a U.S. developed Gas Exchange Measurement System (GEMS) that measures a range of environmental parameters plus transpiration, photosynthesis, and possibly respiration. Environmental parameters include cabin, chamber, root-zones, and leaf temperatures. Light levels, relative humidity, oxygen, and atmospheric pressure are also measured. High-accuracy water-vapor and carbon-dioxide concentrations and differences are measured using specially developed IRGA systems.

The Avionics Air Assembly Cooling Package which provides cooling for high heat load racks aboard the International Space Station has been designed and developed to balance challenging requirements for noise emissions, emitted vibrations, power usage, weight, and volume. The assembly consists of a high speed selectable flow fan, a compact air-to-water heat exchanger, noise attenuation components, motor controller electronics, and mounting structure. This paper addresses the final hardware configuration and performance characteristics and the successful development program that was required to create the first qualification/flight assembly. It describes the initial component development hardware performance, the initial package integration results, the completed optimization effort, and the final package performance. These optimization cycles, both to improve and reduce component performance, were necessary to attain the desired package results from this highly integrated assembly.

The generation (and recovery) of water, rather than the reduction of CO2, drives the requirements for the integration of a Sabatier CO2 Reduction Subsystem (SCRS) within an Air Revitalization Subsystem (ARS). It is important, therefore, to understand the system level decisions that impact the water production capability of the Sabatier CO2 Reduction Subsystem. This paper defines each of the operational parameters that affect water production and loss and explores the impact they each have on total water recovery. The particular subsystem parameters examined include hydrogen and carbon dioxide flow rates, feed gas composition, subsystem operating pressure, condensing heat exchanger performance, heat sink temperature, and phase separator performance. Each of these has a minor contribution to the amount of water lost from the system, but combined, their effect is substantial.

Based on the high volume of Extravehicular Activity (EVA) needed for assembly and operation of the International Space Station (1792 hrs through GFY2005), a large number of new crewmembers will be trained in the use of the Extravehicular Mobility Unit (EMU). In addition, the crewmembers will require on-orbit refresher training in the use of an EMU given their extended duration on-orbit of 90-180 days. Currently, there is a single hardware based training unit at Johnson Spaceflight Center (JSC) (the MALF II Simulator). This paper reports on the development of a software based training simulator (EMU Malfunction Training Simulator [EMTS]) which will run on any PC under Microsoft Windows and will be used to supplement MALF II.

Hamilton Standard’s subsidiaries, Microtecnica/Italy and Hamilton Standard Space Systems International/USA, have collaborated to design and fabricate a Water Pump Package (WPP) for the International Space Station (ISS) Multi-Purpose Logistics Module (MPLM). MPLM active payloads (Refrigerator/Freezer Racks (R/FR)) supply cold volume for food and scientific sample storage. The MPLM Active Thermal Control Subsystem (ATCS) maintains specific structural and equipment temperatures for the active payloads. The active thermal control is provided via a low temperature water loop whose flow rate is created by the WPP during MPLM pre-launch and MPLM pre-ISS attach and post-ISS detach mission phases. The WPP also provides compensation for water loop volume variations. This paper will provide a detailed overview of the MPLM Water Pump Package design, as well as providing system performance data.

The International Space Station's primary external heat transport system is a single phase ammonia loop called the Active Thermal Control System (ATCS). ATCS loop heat is acquired from the station modules through interface heat exchangers (Internal Thermal Control System water to ATCS ammonia) and from external truss mounted electronics through cold plates. The heat exchangers are compact plate/fin counterflow type and the cold plates are a brazed and bonded construction using a radiation heat transfer interface to the electronics.

During 1995, we tested instruments and attempted a seed-to-seed experiment with Super-Dwarf wheat in the Russian Space Station Mir. Utah instrumentation included four IR gas analyzers (CO2 and H2O vapor, calculate photosynthesis, respiration, and transpiration) and sensors for air and leaf (IR) temperatures, O2, pressure, and substrate moisture (16 probes). Shortly after planting on August 14, three of six fluorescent lamp sets failed; another failed later. Plastic bags, necessary to measure gas exchange, were removed. Hence, gases were measured only in the cabin atmosphere. Other failures led to manual watering, control of lights, and data transmission. The 57 plants were sampled five times plus final harvest at 90 d. Samples and some equipment (including hard drives) were returned to earth on STS-74 (Nov. 20). Plants were disoriented and completely vegetative. Maintaining substrate moisture was challenging, but the moisture probes functioned well.

The International Space Station Alpha Electrical Power System has a thermal control system to remove heat from the batteries and power distribution electronics. A major subsystem of this thermal loop is the Pump and Flow Control Subassembly (PFCS) which functions as an ammonia fluid distribution and control subsystem. This paper will detail the development, construction and operational performances of the PFCS hydraulic elements operating with an ammonia fluid. These elements include flow meter, accumulator, flow control valve, and pumps. The electronics which are utilized to operate these hydraulic elements will also be described. The combination of these hydraulic and electronic elements form a subassembly to safely control a hazardous, low viscosity fluid.

The Extravehicular Mobility Unit (EMU) used by astronauts during space walks is powered by an 11-cell, silver-zinc battery. The present battery is certified for 6 cycles with a minimum discharge requirement of 7 hours above 16.0 volts at a 3.8 Amp load. Its certified wet-life is 170 days. Operational requirements for the International Space Station (ISS) led to a design capable of 32 cycles over a 425 day wet-life. Other battery parameters including capacity, rate capability, weight, volume, safety and the need for continuing compatibility with the EMU and the Space Shuttle charger dictate that the new battery will also be silver-zinc.

Hamilton Standard Space Systems International, Inc. is currently under contract to NASA for the development and certification of an advanced technology regenerable carbon dioxide removal system for the International Space Station Extravehicular Mobility Unit (EMU), or “space suit.” This new metal-oxide-based system (“Metox”) will replace the existing non-regenerable lithium hydroxide (LiOH) carbon dioxide (CO2) removal system located in the EMU's Primary Life Support System (PLSS). The Metox canister is designed to replace the current LiOH Contamination Control Canister (CCC) with no modification to existing EMU interfaces. The metal oxide sorbent is “regenerable” and can be restored to its original condition permitting the Metox canisters to be used over and over again on-orbit. Once a Metox canister becomes “loaded” with CO2, it will be placed in the “Regenerator,” where the system will circulate hot air through the canister to drive off, or desorb, the CO2.

This paper is concerned with preventing decompression sickness (DCS) in cosmonauts during extravehicular activities (EVAs). The reasons of a significant discrepancy between the DCS risk for usual subjects during simulation of EVA in altitude chambers and ones for cosmonauts during real EVA performance are discussed. Presented here are means and methods of DCS prevention which form the basis of the Russian and U.S. protocols of preparing to go EVA. Performed analysis of effect of physical-chemical properties of inert components of breathing mixtures on the rate of washin and washout of these gases from body tissues and on dynamics of tissue gas bubbles shows that it is expedient to use the normobaric neon-oxygen atmosphere in spacecrafts as a means of increase in decompression safety and effectiveness of EVA.

Potable- and hygiene-quality water will be supplied to crews on the International Space Station through the recovery and purification of spacecraft wastewaters, including humidity condensate, urine, and wash water. Contaminants released into the cabin air from human metabolism, hardware offgassing, flight experiments, and routine operations will be present in spacecraft humidity condensate; normal constituents of urine and bathing water will be present in urine and untreated wash water. This report describes results from detailed analyses of Mir reclaimed potable water, ground-supplied water, and humidity condensate. These results are being used to develop and test water recycling and monitoring systems for the International Space Station (ISS); to evaluate the efficiency of the Mir water processors; and to determine the potability of the recycled water on board.