Searching for biomarkers on Mars

The ExoMars Trace Gas Orbiter has set new upper limits on methane, ethane, ethylene and phosphine in the martian atmosphere, finding very little evidence for their existence.
The gases are often associated with biological or geological processes, so understanding if they are present or not on another planet is key to understanding what processes may or may not be active on Mars today.

Read more in ExoMars orbiter continues hunt for key signs of life on Mars