During recent years much effort has been expended in attempting to develop principles, techniques, and instrumentation leading to the ultimate goal of utilizing photosynthetic organisms for the support of man in an extraterrestrial environment. This study was designed to determine if solar illuminated photosynthetic gas exchange systems would be feasible, and to provide sufficient data to determine if further consideration of this approach would be warranted.
Comparative growth and photosynthetic data of two species of algae under various conditions are presented. Chlorella pyrenoidosa, strain TX 71105, and the 52° C strain of Synechococcus lividus were cultured in thin films in hemispherical domes and solar oriented flat panels during the long Alaskan days of June and July 1961. Growth and photosynthetic rates were measured in cultures having film depths of 1, 2 and 4 cm under solar illumination. The maximum production rate observed in the flat panels was over 50 grams of algae and approximately I00 liters (STP) of oxygen per square meter of illuminated surface per day. Based on the observed data, it is estimated that the illuminated area of algal suspension required for a one man gas exchanger will be six square meters or less. The maximum volume of the illuminator will be 60 liters. A small additional volume must be added for pumping and for gas exchange.