Examination of Gas Sample Bags for Long-Term of Air Storage Samples 2004-01-2335

The Photosynthesis Experiment and System Testing and Operations (PESTO) experiment spent a total of 73 days in microgravity, both on shuttle (STS-110 and -111) and Internatioal Space Station (ISS). Valuable data was collected from chambers in which wheat (Triticum aestivum cv. Apogee) or Brassica rapa cv. Astroplant were grown. Among the data collected were air samples stored in 3 × 5″ Cali-5-Bond bags. After returning to Earth, each sample bag was analyzed for atmospheric composition by gas chromatography. Unexplainable results led to the current investigation. Thirty mL aliquots of five % (volume/volume) CO₂ were placed into each of 12 bags. As a control, 30 mL of room air were placed into each of four bags. Two 0.5-mL samples were removed from each bag immediately after filling, and after 28 to 30 days; these samples were analyzed within one minute of collection by gas chromatography. Analytical results indicate significant changes in the CO₂ concentration in all of the sample bags. Further testing is under way to determine whether the current bag design is acceptable for future spaceflight experiments.