ISS037-E-001078 (12 Sept. 2013) --- European Space Agency astronaut Luca Parmitano, Expedition 37 flight engineer, performs in-flight maintenance behind a rack in Tranquility node of the International Space Station. Parmitano replaced a mass spectrometer inside the Major Constituent Analyzer (MCA). The MCA measures the levels of nitrogen, oxygen, carbon dioxide, methane, hydrogen and water vapor inside the space station’s atmosphere.
Date September 12, 2013