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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.

The first spaceflight opportunities for Advanced Life Support (ALS) Project testing with plants will likely occur with missions on vehicles in Low Earth Orbit, such as the International Space Station (ISS). In these settings, plant production systems would likely be small chambers with limited electrical power. Such systems are adequate for salad-type crops that provide moderate quantities of fresh, flavorful foods to supplement the crew diet. Successful operation of salad crop systems in the space environment requires extensive ground-based testing with horticultural methodologies that meet expected mission constraints. At Kennedy Space Center, cultivars of radish, onion, and lettuce are being compared for performance under these “flight-like” conditions.

Radish (Raphanus sativus L.), green onion (Allium fistulosum L.), and lettuce (Lactuca sativa L.) are among several “salad” crop species suggested for use on the International Space Station (ISS) as a supplement to the crew’s diet. Among the more important factors affecting the crop yields will be the light intensity or photosynthetic photon flux (PPF) used to grow the plants. Radish (cv. Cherry Bomb), green onion (cv. Kinka), and lettuce (cv. Flandria) plants were grown for 35 days in growth chambers at 8.6, 17.2, and 26 mol m−2 d−1 (150, 300, or 450 μmol m−2 s−1 PPF, respectively) with a 16 hr photoperiod and cool-white fluorescent lamps and either 400 or 1200 μmol mol−1 CO2. Final (35-day) edible yields were taken for the treatments under ambient or supplemented CO2. Results showed a response of growth to incident PPF that indicated a strong influence of lighting on yields.