The European Space Agency has begun the first stage of a two-part mission to explore Mars and hunt for signs of life on the red planet.

The unmanned ExoMars probe — a collaborative project with Russia's Roscosmos — was launched aboard a Russian rocket Monday and is expected to reach Mars in October.

The probe consists of an orbiter that will analyze gases in the atmosphere of Mars, and a small lander that will put a rover on the surface in 2018.

Europe's Beagle 2 probe disappeared during the landing process in 2003, a setback which ESA is keen to avoid this time.

Paolo Ferri, ESA's head of mission operations, says traces of methane previously discovered in the Martian atmosphere indicate recent geological or even biological activity.