The robot has just completed environmental testing at the Airbus factory in Toulouse, France, and is now going east to another aerospace facility run by Thales Alenia Space.
It's on the French Riviera, in Cannes, that the vehicle will join the hardware that will carry it to the Red Planet and put it safely on the surface.
Once this integration is complete, the rover can then go for launch.
Rosalind Franklin is due to leave Earth in July or August this year on a Proton rocket, arriving at Mars in March 2021.
The six-wheeled robot is equipped with scientific instruments designed to look for signs of life.
The project is a joint venture of the European Space Agency (Esa) and its Russian counterpart, Roscosmos.
Rosalind Franklin was assembled in the UK over a period of about 18 months. Airbus then took the vehicle to Toulouse to put it in a thermal-vacuum chamber - a testing unit that can simulate the extreme conditions of travelling to, and working on, Mars.
Having survived this challenge of heat, cold and airlessness, the rover must now be joined to its entry, descent and landing (EDL) system; and the spacecraft that will shepherd everything to the Red Planet.
These other elements have been manufactured by different companies across Europe and Russia; and it is the job now of Thales Alenia Space, as prime contractor, to make sure all parts work together.
Assuming no technical problems in this fit-check are encountered, the entire hardware package can move to the Baikonur Cosmodrome in Kazakhstan to meet the launch Proton.
In parallel to all this, Esa continues to work on the parachutes that will help slow Rosalind Franklin during its EDL phase. These chutes, which will be deployed at high velocity, have experienced tearing during testing.
They must perform flawlessly in two final high-altitude practice deployments in the US in the coming weeks before the final go-ahead for the rover mission is given.
BBC News
