The ExoMars Trace Gas Orbiter is on a multiyear mission to understand the tiny amounts of methane and other gases in Mars’ atmosphere that could be evidence for possible biological or geological activity.
Trace Gas Orbiter at Mars

What is a trace gas?

A trace gas makes up less then 1% by volume of a planet’s atmosphere. Trace gases in the martian atmosphere include methane, water vapour, nitrogen dioxide and acetylene. Although making up a very small amount of the overall atmospheric inventory, methane in particular holds key clues to the planet’s current state of activity.

Last update: 3 March 2016

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