Instead, the agency turned to Russia to launch the orbiter and rover on two Proton rockets and provide the descent system to deliver the rover to Mars. In exchange, ESA agreed to add Russian science instruments to the orbiter and rover missions. This was a boon for Russian scientific institutions. Without an international partnership like ExoMars, they lacked any realistic prospect of ever sending their own research payloads to the red planet.

Russia successfully launched the European-built ExoMars Trace Gas Orbiter spacecraft on a Proton rocket in 2016. The orbiter is still operating around Mars today, returning scientific data and serving as a communications relay for NASA’s Curiosity and Perseverance rovers. A small European tech demo probe riding piggyback on the orbiter crash landed upon reaching the red planet.

Additional delays pushed the the launch of the ExoMars rover from 2018 until 2020. The rover, by then named for the late British chemist and DNA research pioneer Rosalind Franklin, was nearly ready for launch in 2020 when a series of parachute test failures and the COVID-19 pandemic prompted another delay until late 2022.

Everything changed again when Russian forces invaded Ukraine in February 2022. ESA severed most ties with Russia’s space agency, ending the partnership on ExoMars after all of the mission’s elements, including the Russian rocket and Mars descent stage, were already built and ready for final assembly. ESA also removed two Russian science instruments from the mission.

Once again, the US government stepped in to give the Rosalind Franklin rover a ride to Mars. NASA and ESA formalized the new agreement in 2024, with the US side committing to provide a launch vehicle, the braking engines needed to land, and small nuclear-powered heaters to keep the rover’s sensitive electronics warm during Martian nights. NASA long ago delivered a mass spectrometer for the European rover that will analyze Martian soil to look for markers of organic molecules.

ESA is providing the rover and the carrier spacecraft to ferry it to Mars. Europe is also responsible for the overall assembly of the landing platform and operating the rover on the Martian surface. Airbus built the rover in the United Kingdom and is supplying the main structure for the lander, which will settle onto Mars and deploy ramps for the rover to disembark and begin its mission. The German company OHB manufactured the carrier spacecraft, or cruise stage, to shepherd the rover from Earth to Mars. Thales Alenia Space of Italy is in charge of putting all the pieces together and readying the mission for launch.