It will incorporate a Russian-led surface platform and European-led rover, to be launched from the Baikonur spaceport in Kazakhstan.
The decision to put back the launch was a joint one that took into account delays in European and Russian industrial activities, the European agency said in a statement.
A spacecraft left Baikonur in March in the first stage of the program.
It carried an atmospheric probe that is to study trace gases such as methane -- a chemical that on Earth is strongly tied to life - that previous Mars missions have detected in the planet`s atmosphere. The craft is due to arrive in October.
The second-stage rover is meant to be the first with the ability to both move across Mars` surface and drill into the ground to collect and analyze samples.
Roscosmos was not available for comment on Monday, a public holiday in Russia.
More about:
