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As part of NASA’s TransHab inflatable habitat program, a Radiation Shield Water Tank (RSWT) is being developed to provide a safe haven from peak solar particle events. The RSWT will provide an 11 ft. (3.35 m) diameter by 7 ft. (2.13 m) tall “safe haven” with a 2.26 in. (0.0574 m) thick wall of water for astronaut residence during peak solar events. The RSWT also functions as a water processing storage tank and must be capable of being filled and drained at will. Because of the unique shape of the RSWT, standard bellows and bladder designs cannot be used for inventory control. Therefore NASA has developed a bladderless tank where capillary forces govern the positioning of the liquid inventory. A combination of hydrophobic and hydrophilic membranes and wetting surfaces allows the tank to be filled and emptied as desired. In the present work, background on space-borne radiation is presented, the bladderless RSWT concept is described, and its theory of operation is discussed.

A technology project to produce a new space suit for planetary applications started in January of 1997, with a thermal vacuum test of the system, including a suited crew member, expected in the year 2000. This will be a progress report on the activities that occurred during the project's first year. The four year project is funded out of Code M at NASA Headquarters and is an effort to integrate the latest EVA technology into a maintainable modular design. The project will use as much off-the-shelf hardware as practical in an effort to lower development cost and decrease development time. Three pressurized garment configurations will be evaluated and two different portable life support systems will be built. The first year was primarily spent developing laboratories, bench-top working laboratory subsystems, analytical models, and the overall requirements and architecture of the system.

Current dosimetric practices do not provide comprehensive classification of high-energy charged particle radiation, so that the ability to adequately project health risk to astronaut crews is limited. To address this shortcoming in dosimetry for Space Station missions, a new generation of active radiation monitors is being developed to supplement traditional dosimetry. One active monitor is a Tissue Equivalent Proportional Counter (TEPC) to measure the linear energy transfer (LET) spectrum of space radiation. Two versions of a second type of active monitor, the Charged Particle Directional Spectrometer (CPDS), will be deployed, one internal and one external to the Station. The CPDS consists of a stack of lithium-drifted silicon detectors used to classify the radiation by particle charge and energy. The comprehensive data set obtained by using the TEPC and the CPDS permits significant improvement in assessing crew radiation exposures.

The Microbial Check Valve (MCV) is used on the Space Shuttle to impart an iodine residual to the drinking water to maintain microbial control. Approximately twenty MCV locations have been identified in the Space Station Freedom design, each with a 90 day life. This translates to 2400 replacement units in 30 years of operation. An in situ regeneration concept has been demonstrated that will reduce this replacement requirement to less than 300 units based on data to date and potentially fewer as further regenerations are accomplished. A totally automated system will result in significant savings in crew time, resupply requirements and replacement costs. An additional feature of the device is the ability to provide a concentrated biocide source (200 mg/liter of I2) that can be used to superiodinate systems routinely or after a microbial upset. This program was accomplished under NASA Contract Number NAS9-18113.

Iodine is the disinfectant used in U.S. spacecraft potable water systems. Recent long-term testing on human subjects has raised concerns about excessive iodine consumption. Efforts to reduce iodine consumption by Shuttle crews were initiated on STS-87, using hardware originally designed to deiodinate Shuttle water prior to transfer to the Mir Space Station. This hardware has several negative aspects when used for Shuttle galley operations, and efforts to develop a practical alternative were initiated under a compressed development schedule. The alternative Low Iodine Residual System (LIRS) was flown as a Detailed Test Objective on STS-95. On-orbit, the LIRS imparted an adverse taste to the water due to the presence of trialkylamines that had not been detected during development and certification testing. A post-flight investigation revealed that the trialkylamines were released during gamma sterilization of the LIRS resin materials.

One of the proposed methods for monitoring the microbial quality of the water supply aboard the International Space Station is membrane filtration. We adapted this method for space flight by using an off-the-shelf filter unit developed by Millipore. This sealed unit allows liquid to be filtered through a 0.45 μm cellulose acetate filter that sits atop an absorbent pad to which growth medium is added. We combined a tetrazolium dye with R2A medium to allow microbial colonies to be seen easily, and modified the medium to remain stable over 70 weeks at 25°C. This hardware was assembled and tested in the laboratory and during parabolic flight; a modified version was then flown on STS-66. After the STS-66 mission, a back-up plastic syringe and an all-metal syringe pump were added to the kit, and the hardware was used successfully to evaluate water quality aboard the Russian Mir space station.

The Orion Crew and Service Modules are often compared to the Apollo Command and Service Modules due to their similarity in basic mission objective: both were dedicated to getting a crew to lunar orbit and safely returning them to Earth. Both spacecraft rely on the environmental control, life support and active thermal control systems (ECLS/ATCS) for the basic functions of providing and maintaining a breathable atmosphere, supplying adequate amount of potable water and maintaining the crew and avionics equipment within certified thermal limits. This assessment will evaluate the driving requirements for both programs and highlight similarities and differences. Further, a short comparison of the two system architectures will be examined including a side by side assessment of some selected system's hardware mass.