In June, NASA’s Curiosity rover reported the highest burst of methane recorded yet, but neither ESA’s Mars Express nor the ExoMars Trace Gas Orbiter recorded any signs of the illusive gas, despite flying over the same location at a similar time.
New press release from ESA: http://www.esa.int/Science_Exploration/Human_and_Robotic_Exploration/Exploration/ExoMars/ESA_s_Mars_orbiters_did_not_see_latest_Curiosity_methane_burst
NOMAD - Nadir and Occultation for MArs Discovery