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A Total Organic Carbon (TOC) Analyzer has been developed for a Life Sciences Risk Mitigation Flight Experiment to be conducted on Spacehab and the Russian space station, Mir. Initial launch is scheduled for December 1996 (flight STS-81). The analyzer will be tested on the Orbiter in the Spacehab module, including when the Orbiter is docked at the Mir space station. The analyzer is scheduled to be launched again in May 1997 (STS-84) when it will be transferred to Mir. During both flights the analyzer will measure the quality of recycled and ground-supplied potable water on the space station. Samples will be archived for later return to the ground, where they will be analyzed for comparison to in-flight results. Water test samples of known composition, brought up with the analyzer, also will be used to test its performance in microgravity. Ground-based analyses of duplicates of those test samples will be conducted concurrently with the in-flight analyses.

During 1987 three space station integrated Environmental Control and Life Support System (ECLSS) tests were conducted at the Marshall Space Flight Center (MSFC) Core Module Integration Facility (CMIF) as part of the MSFC ECLSS Phase II test program. The three tests ranged in duration from 50 to 150 hours and were conducted inside of the CMIF module simulator. The Phase II partial integrated system test configuration consisted of four regenerative air revitalization subsystems and one regenerative water reclamation subsystem. This paper contains a discussion of results and lessons learned from the Phase II test program. The design of the Phase II test configuration and improvements made throughout the program are detailed. Future plans for the MSFC CMIF test program are provided, including an overview of planned improvements for the Phase III program.

Trace contaminants are produced on-orbit by human metabolic processes and equipment off-gassing. These potentially hazardous contaminants are removed by the Trace Contaminant Control Subassembly (TCCS) in the US segment of the International Space Station (ISS). The TCCS has been operating since February 2001. Analysis of on-orbit telemetry data indicated a slow increase in the TCCS system flow resistance over the five years of operation. Two of the packed beds within the TCCS were replaced to return the TCCS to its nominal operation conditions: the high temperature catalytic oxidizer and the post-sorbent bed. Results from the examination of the returned beds are presented along with a discussion about changes to bed service life.

The Johnson Space Center Water and Food Analytical Laboratory (WAFAL) performed detailed ground-based analyses of archival water samples for verification of the chemical quality of the International Space Station (ISS) potable water supplies for Expeditions 14 and 15. During the 12-month duration of both expeditions, the Space Shuttle docked with the ISS on four occasions to continue construction and deliver additional crew and supplies; however, no Shuttle potable water was transferred to the station during Expedition 14. Russian ground-supplied potable water and potable water from regeneration of humidity condensate were both available onboard the ISS for consumption by the Expeditions 14 and 15 crews. A total of 16 chemical archival water samples were collected with U.S. hardware during Expeditions 14 and 15 and returned on Shuttle flights STS-116 (12A.1), STS-117 (13A), STS-118 (13A.1), and STS-120 (10A) in December 2006, and June, August, and November of 2007, respectively.

Humidity condensate collected and processed in-flight is an important component of a space station drinking water supply. Water recovery systems in general are designed to handle finite concentrations of specific chemical components. Previous analyses of condensate derived from spacecraft and ground sources showed considerable variation in composition. Consequently, an investigation was conducted to collect condensate on the Shuttle while the vehicle was docked to Mir, and return the condensate to Earth for testing. This scenario emulates an early ISS configuration during a Shuttle docking, because the atmospheres intermix during docking and the condensate composition should reflect that. During the STS-89 and STS-91 flights, a total volume of 50 liters of condensate was collected and returned. Inorganic and organic chemical analyses were performed on aliquots of the fluid.

With the Shuttle fleet grounded, limited capability exists to resupply in-flight water quality monitoring hardware onboard the International Space Station (ISS). As such, verification of the chemical quality of the potable water supplies on ISS has depended entirely upon the collection, return, and ground-analysis of archival water samples. Despite the loss of Shuttle-transferred water as a water source, the two-man crews during Expedition 8 and Expedition 9 maintained station operations for nearly a year relying solely on the two remaining sources of potable water; reclaimed humidity condensate and Russian-launched ground water. Archival potable water samples were only collected every 3 to 4 months from the systems that regenerate water from condensate (SRV-K) and distribute stored potable water (SVO-ZV).

At present, spacecraft water quality is assessed when samples collected on the International Space Station (ISS) are returned to Earth. Several months, however, may pass between sample collection and analysis, potentially compromising sample integrity by risking degradation. For example, iodine and silver, which are the respective biocides used in the U.S. and Russian spacecraft potable water systems, must be held at levels that prevent bacterial growth, while avoiding adverse effects on crew health. A comparable need exists for the detection of many heavy metals, toxic organic compounds, and microorganisms. Lead, cadmium, and nickel have been found, for instance, in the ISS potable water system at amounts that surpass existent requirements. There have been similar occurrences with hazardous organic compounds like formaldehyde and ethylene glycol. Microorganism counts above acceptable limits have also been reported in a few instances.

Colorimetric-solid phase extraction (C-SPE) is being developed as a method for in-flight monitoring of spacecraft water quality. C-SPE is based on measuring the change in the diffuse reflectance spectrum of indicator disks following exposure to a water sample. Previous microgravity testing has shown that air bubbles suspended in water samples can cause uncertainty in the volume of liquid passed through the disks, leading to errors in the determination of water quality parameter concentrations. We report here the results of a recent series of C-9 microgravity experiments designed to evaluate manual manipulation as a means to collect bubble-free water samples of specified volumes from water sample bags containing up to 47% air. The effectiveness of manual manipulation was verified by comparing the results from C-SPE analyses of silver(I) and iodine performed in-flight using samples collected and debubbled in microgravity to those performed on-ground using bubble-free samples.

Advanced life support flight experiments have been conceptualized for the International Space Station (ISS). Two of the experiments, a high pressure oxygen generator and a carbon dioxide reduction subsystem, offer high payback potential to the ISS program. This paper documents the cost-benefit analyses for these two experiments.

In preparation for the contract award of the Crew Exploration Vehicle (CEV), the National Aeronautics and Space Administration (NASA) produced two design reference missions for the vehicle. The design references used teams of engineers across the agency to come up with two configurations. This process helped NASA understand the conflicts and limitations in the CEV design, and investigate options to solve them.

The International Space Station (ISS) loses cabin atmosphere mass at some rate. Due to oxygen partial pressures fluctuations from metabolic usage, the total pressure is not a good data source for tracking total pressure loss. Using the nitrogen partial pressure is a good data source to determine the total on-orbit cabin atmosphere loss from the ISS, due to no nitrogen addition or losses. There are several important reasons to know the daily average cabin air loss of the ISS including logistics planning for nitrogen and oxygen. The total average daily cabin atmosphere loss was estimated from January 14 to April 9 of 2003. The total average daily cabin atmosphere loss includes structural leakages, Vozdukh losses, Carbon Dioxide Removal Assembly (CDRA) losses, and other component losses.

In support of Space Station Freedom Phase C/D Environmental Control and Life Support Systems (ECLSS) regenerative systems development, comparative testing was performed on predevelopment hardware of competing technologies for each regenerative function. This testing was conducted by The Boeing Aerospace and Electronics Company (BAE) at Marshall Space Flight Center (MSFC) from late 1989 through early 1990. The purpose of the test program was to collect data on latest generation hardware in order to make final technology selections for each subassembly in the oxygen recovery and water reclamation strings. This paper discusses the testing performed, test results, and evaluation of these results relative to subsystem selections for CO2 reduction, O2 generation, potable water processing, hygiene water processing, and urine processing.

The baseline environmental control and life support (ECLS) systems currently deployed on board the International Space Station (ISS) and that planned to be launched in Node 3 are based upon technologies selected in the early 1990's. While they are generally meeting or exceeding requirements for supporting the ISS crew, lessons learned from years of on orbit and ground testing, together with new advances in technology state of the art, and the unique requirements for future manned missions prompt consideration of the next logical step to enhance these systems to increase performance, robustness, and reliability, and reduce on-orbit and logistical resource requirements. This paper discusses the current state of the art in ISS ECLS system technologies, and identifies possible areas for enhancement and improvement.

The Space Shuttle Program has recently embarked on a program which will lengthen the on-orbit stay time of the Space Shuttle. In its current configuration, the orbiter is limited to a maximum of 10 days by Environmental Control and Life Support System (ECLSS) consumables, stowage constraints, and the fuel cell reactants. The capabilities of the Extended Duration Orbiter (EDO) will permit longer duration Spacelab, Spacehab, and Commercially Developed Space Facility (CDSF) missions. Additionally, the EDO may be required for Space Station Freedom assembly operations in the late 1990's. Of the National Aeronautics and Space Administration's (NASA) fleet, both Columbia (OV-102) and Endeavour (OV-105) will be modified to accomplish extended missions of up to 16 days. As a logical follow-on, NASA is currently pursuing approval of a 28-day Extended Duration Orbiter program.

On the International Space Station (ISS), humidity condensate will be collected from the atmosphere and treated by multifiltration to produce potable water for use by the crews. Ground-based development tests have demonstrated that multifiltration beds filled with a series of ion-exchange resins and activated carbons can remove many inorganic and organic contaminants effectively from wastewaters. As a precursor to the use of this technology on the ISS, a demonstration of multifiltration treatment under microgravity conditions was undertaken. On the Space Shuttle, humidity condensate from cabin air is recovered in the atmosphere revitalization system, then stored and periodically vented to space vacuum. A Shuttle Condensate Adsorption Device (SCAD) containing sorbent materials similar to those planned for use on the ISS was developed and flown on STS-68 as a continuation of DSO 317, which was flown initially on STS-45 and STS-47.

Spacecraft hardware trade studies compare options primarily on mass while considering impacts to cost, risk, and schedule. Historically, other factors have been considered in these studies, such as reliability, technology readiness level (TRL), volume and crew time. In most cases, past trades compared two or more technologies across functional and TRL boundaries, which is an uneven comparison of the technologies. For example, low TRL technologies with low mass were traded directly against flight-proven hardware without consideration for requirements and the derived architecture. To provide for even comparisons of spacecraft hardware, trades need to consider functionality, mission constraints, integer vs. real number of flight hardware units, and mass growth allowances by TRL.

Archival sampling of potable water and condensate for ground laboratory analysis has been an important part of the Shuttle-Mir program because of coolant leaks and other events on Mir that have affected water quality. We report here the development of and preliminary results from a novel device for single phase humidity condensate collection at system pressures. The sampler consists of a commercial-off-the-shelf Teflon® bladder and a custom reinforced Nomex® restraint that is sized properly to absorb the stress of applied pressures. A plastic Luer-Lock disconnect, with poppet actuated by a mating Luer-Lock fitting, prevents the contents from being spilled during transport. In principle, a sampler of any volume can be designed. The empty mass of the reusable one-liter sampler is only 63 grams. Several designs were pressure tested and found to withstand more than 3 atmospheres well in excess of typical spacecraft water or wastewater system pressures.

During the twelve month period comprising Expeditions 10 and 11, the chemical quality of the potable water onboard the International Space Station (ISS) was verified through the return and ground analysis of water samples. The two-man Expedition 10 crew relied solely on Russian-provided ground water and reclaimed cabin humidity condensate as their sources of potable water. Collection of archival water samples with U.S. hardware has remained extremely restricted since the Columbia tragedy because of very limited return volume on Russian Soyuz vehicles. As a result only two such samples were collected during Expedition 10 and returned on Soyuz 9. The average return sample volume was only 250 milliliters, which limited the breadth of chemical analysis that could be performed. Despite the Space Shuttle vehicle returning to flight in July 2005, only two potable water samples were collected with U.S. hardware during Expedition 11 and returned on Shuttle flight STS-114 (LF1).

Ever since the first crew arrived at the International Space Station (ISS), archival potable water samples have been collected and returned to the ground for detailed chemical analysis in order to verify that the water supplies onboard are suitable for crew consumption. The Columbia tragedy, unfortunately, has had a dramatic impact on continued ISS operations. A major portion of the ISS water supply had previously consisted of Shuttle-transferred water. The other two remaining sources of potable water, i.e., reclaimed humidity condensate and Russian-launched ground water, are together insufficient to maintain 3-person crews. The Expedition 7 crew launched in April of 2003 was, therefore, reduced from three to two persons. Without the Shuttle, resupply of ISS crews and supplies is dependent entirely on Russian launch vehicles (Soyuz and Progress) with severely limited up and down mass.

Potable water supplies onboard the International Space Station (ISS) include both reclaimed water from treatment of atmospheric humidity condensate and stored water that is either Shuttle-transferred or ground-supplied. Space station medical operations requirements call for real-time monitoring of key water quality parameters, such as total organic carbon, total inorganic carbon, total carbon, pH, and conductivity, to ensure that crew health is protected from unsafe drinking water. A Total Organic Carbon Analyzer (TOCA) designed to meet these requirements was developed as part of the Crew Health Care System and launched to the ISS in April of 2001. The initial design of the ISS TOCA was previously presented at this conference in 1998. The current design of the instrument includes an improved reagent system and upgraded software to enhance accuracy through the capability to measure organic contamination of the reagents and correct analytical results.