Autonomous Calibration of Vehicle Cabin Atmosphere Monitor

The vehicle cabin atmosphere monitor (VCAM) is designed to autonomously detect and identify trace organic species in the international space station (ISS) cabin air and monitor changes in species concentrations over time after chemical events. VCAM uses a gas chromatograph and quadrupole ion trap mass spectrometer to separate chemical analytes and determine mass fractionation patterns of the chemical analytes. In order to obtain the desired mass resolution and dynamic range, several instrument parameters must be calibrated. We present our lessons learned developing a heuristic calibration procedure and translating the procedure into a procedure suitable for direct conversion to flight software. The heuristic procedure involves the detection of changes in signal trends that humans can easily recognize, but are not necessarily straightforward to codify in an algorithm. We developed an algorithm by working closely with instrument experts and designed several test cases and data sets to verify that the algorithm achieved the same as the original human heuristics.