Artist’s impression of the ExoMars 2016 Trace Gas Orbiter at Mars.

After the smooth arrival of ESA’s latest Mars orbiter, mission controllers are now preparing it for the ultimate challenge: dipping into the Red Planet’s atmosphere to reach its final orbit.

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.

Following its long journey from Earth, the orbiter fired its main engine on 19 October to brake sufficiently for capture by the planet’s gravity.

It entered a highly elliptical orbit where its altitude varies between about 250 km and 98 000 km, with each circuit taking about four Earth days.

Ultimately, however, the science goals and its role as a data relay for surface rovers mean the craft must lower itself into a near-circular orbit at just 400 km altitude, with each orbit taking about two hours.