VFEU water quality control in STS-95 mission.

In STS-95 Space Shuttle mission, an aquatic animal research facility, Vestibular Function Experiment Unit (VFEU), was flown to perform neurobiological experiment with marine fish, oyster toadfish. For this purpose, we have developed a sea water purification system using highly active nitrifying bacteria at low temperature. With this system, the water quality in the VFEU was maintained in sufficient condition to keep the toadfish in healthy state for 9 days of the mission. This report summarizes the efficiency of the filter system based on the results from pre-flight bacterial preparation, water analysis of samples taken during flight, and the post-flight analysis of the bacterial filter.