The methane mystery on Mars has had many twists and turns in recent years with unexpected detections and non-detections alike. Most recent is the detection in June by NASA’s Curiosity rover, which reported the highest burst of methane recorded yet. However, neither ESA’s Mars Express nor the ExoMars Trace Gas Orbiter recorded any signs of the elusive gas, despite flying over the same location at a similar time.
BIRA-IASB’s NOMAD-instrument, on board ExoMars TGO, can measure trace gases such as methane down to very low concentrations, almost down to the Martian surface. It is puzzling that it couldn’t detect what Curiosity saw. The processes behind these observations, the fact that methane appears and disappears more quickly than expected, remain to be explained.