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A reliable nutrient delivery system is essential for long-term cultivation of plants in space. At the Kennedy Space Center, a series of ground-based tests are being conducted to compare candidate plant nutrient delivery systems for space. To date, our major focus has concentrated on the Porous Tube Plant Nutrient Delivery System, the ASTROCULTURE™ System, and a zeoponic plant growth substrate. The merits of each system are based upon the performance of wheat supported over complete growth cycles. To varying degrees, each system supported wheat biomass production and showed distinct patterns for plant nutrient uptake and water use.

This project sought to develop a photocatalytic oxidation (PCO) based total organic carbon (TOC) analyzer for real time monitoring of air quality in spacecraft. Specific requirements for this application were to convert volatile organic contaminants (VOC) into CO2 stoichiometrically in a single pass through a small reactor with low power requirement. One of the greatest challenges of this TiO2-mediated PCO was the incomplete oxidation of some recalcitrant VOCs leading to less reactive intermediates that deactivate the catalyst over time. Dichloromethane (DCM) is one of these VOCs. The effect of some design factors (e.g. TiO2 catalyst surface area to volume ratio and UV photon flux field) as well as operating conditions of an annular reactor (e.g. VOC residence time and relative humidity) on the efficiency in converting DCM to CO2 were investigated.

In controlled environment plant growth chambers, electric lamps provide photons necessary to drive photosynthesis. In order to determine the most productive, energy efficient, and safest way of providing light to plants for a given application, new lighting technologies are being evaluated by various researchers. Light-emitting diodes (LEDs) represent an innovative lighting source with several appealing features specific for supporting plants whether on space-based transit vehicles or planetary life support systems. For this study, there was specific interest in Swiss chard (Beta vulgaris L. cv. ‘Ruby Red Rhubarb') because these plants are among “salad-type” species chosen for early mission testing on Space Station. Of particular interest, were the growth dynamics and gas exchange characteristics of Swiss chard grown under red LEDs at narrow wavebands, which give different ratios of blue quanta to far-red photons.

Microbiological sampling and analysis was performed on the wet waste returned from the STS-105 and STS-108 shuttle missions servicing the International Space Station (ISS). Samples were collected from a variety of materials including plate waste and associated food packaging (which composed the majority of the collected waste), sanitary waste, and loose liquid inside the waste container. Analyses of the microbial loads cultured on both selective and non-selective media and through total bacterial counts by acridine orange direct count (AODC) methods showed high microbial densities in the waste container liquid. Isolates identified included Klebsiella pneumoniae, Serratia marcescens, Bacillus spp., Salmonella spp., and Escherichia coli (E.coli). Dry and ash weights were collected for each sample to determine water and organic content of the materials.

A series of experiments was initiated to characterize plant growth at the elevated temperatures typically observed in the space shuttle and the International Space Station (ISS) to allow for subsequent isolation of temperature effects from those of microgravity. Plants were grown in temperatures ranging from 18-30°C in anticipated flight conditions of light intensity, photoperiod, and CO2 concentration. The effects of these environmental variables on leaf development and anatomy were examined. Results indicate that leaf anatomy is significantly effected by elevated temperature. Leaf thickness decreased with increasing temperature and showed an equal reduction in the thickness of the palisade and spongy mesophyll. Shoot fresh and dry weight/unit leaf area increased with increasing temperature and chlorophyll content was reduced. These results indicate that increased temperature lead to a reduction in intercellular air spaces within the leaf.

In applications that require space-suited crewmembers to traverse rough terrain, boot fit and mobility are of critical importance to the crewmember's overall performance capabilities. Current extravehicular activity (EVA) boot designs were developed for micro-gravity applications, and as such, incorporate only minimal mobility features. Recently three advanced space suit boot designs were evaluated at the National Aeronautics and Space Administration Johnson Space Center (NASA/JSC). The three designs included: 1) a modified Space Shuttle suit (Extravehicular Mobility Unit or EMU) boot, 2) the Modified Experiment Boot designed and fabricated by RD & PE Zvezda JSC, and 3) a boot designed and fabricated by the David Clark Company. Descriptions of each configuration and rationale for each boot design are presented.

With the development of the International Space Station and the need for international collaboration for returning to the moon and developing a mission to Mars, NASA has embarked on developing international educational programs related to space exploration. In addition, with the explosion of educational technology, linking students on a global basis is more easily accomplished. This technology is bringing national and international issues into the classroom, including global environmental issues, the global marketplace, and global collaboration in space. We present the successes and lessons learned concerning international educational and public outreach programs that the Fundamental Space Biology Outreach Program staff have been involved in for NASA as well as the importance of sustaining these international peer collaborative programs for the future generations.

Radish (Raphanus sativus L.) is a salad type crop that is being evaluated for possible use on the International Space Station (ISS). The study will determine the growth and development of radish in the microgravity environment. A series of experiments were initiated to determine whether volatile organic compounds (VOC) that are commonly accumulated in closed systems of spacecraft atmosphere are biologically active. A survey of existing atmospheric samples from the space shuttle and ISS revealed over 260 compounds with potential biogenic activity of which a subset of 14 compounds have been selected for detailed evaluation. Initial screening is achieved by exposing radishes to VOC concentrations corresponding to 0.1 and 1.0 the Spacecraft Maximum Allowable Concentration (SMAC) of the contaminants. Biogenic effects of ethanol at 0.1 of the SMAC resulted in lower chlorophyll content, reduced growth rate, and lower yields.