It will now be transferred from the Airbus factory in Stevenage to Toulouse in France for testing ahead of its proposed nine-month trip to the Red Planet in search of life.
Named after Rosalind Elsie Franklin, a British scientist whose work was central to the discovery of the structure of DNA, scientists hope it will increase human understanding of Mars.
The six-wheeled robot is a part of the ESA’s ExoMars mission to assess the geological landscape of the planet, as well as its microscopic composition.
Its two-meter drill will attempt to unearth protected elements of life buried beneath the surface.
After two primary tests earlier this year flagged up problems with the rover’s parachute capabilities, the Rosalind Franklin must now pass tests in Oregon, US, in November.
If sufficient progress is not demonstrated, the July 2020 launch date could be in jeopardy.
Dr Graham Turnock, chief executive of the UK Space Agency, said that the achievement establishes “the UK’s leading capabilities in robotics, space engineering and exploration.”
The next stage of testing will examine whether it can endure the tumultuous conditions of space before its confirmed launch.
Pietro Baglioni, the ESA’s ExoMars manager, said: “We hope to find evidence of presence of water, which is already clear from other investigations that we have done from missions to Mars so far”.
He added: "Then signs of possible microorganisms, or things that have been related to the presence of water that can bring us to the concept of possible past life on Mars."
Van Odedra, the Airbus ExoMars rover project manager, said: “This is just another big step of the journey to get to Mars.
“We will have a big sigh of relief when the rover is able to get off the platform, drive down along the ramps and get on to start its mission.”
If it launches as planned next summer, it is due to land on Mars on March 19, 2021.