The ExoMars rover mission, set to launch in 2022, has been postponed due to Russia's invasion of Ukraine.
The mission to find life on the Red Planet was a joint Russian-European venture, set to launch from a spaceport in Kazakhstan. Onboard was a European rover and a Russian lander.
However the European Space Agency (ESA) has put that on hold indefinitely amid President Vladimir Putin's widely condemned attacks on Russia's neighbouring country.
In a strongly worded statement, the ESA said it "deeply deplored the human casualties and tragic consequences of this aggression towards Ukraine".
"While recognising the impact on scientific exploration of space, ESA is fully aligned with the sanctions imposed on Russia by its Member States."
The ExoMars rover, named after DNA pioneer Rosalind Franklin, is the second mission by the two organisations to explore Mars.
The first, in 2016, sent an orbiter and lander to the Red Planet. Schiaparelli, the lander, was to be used to test landing technology for future missions but crash-landed instead.
Instruments on the new rover are designed to search for water below the surface of the planet, while others will look for organic compounds in samples. The presence of organic matter would be a key indicator of life.
During a meeting of its ruling council the war in Ukraine impact on the ExoMars mission was discussed and the group "unanimously acknowledged the present impossibility of carrying out the ongoing cooperation with Roscosmos on the ExoMars rover mission with a launch in 2022".
The council also mandated the ESA Director General to suspend all cooperation with Roscosmos and carry out a "fast-track industrial study" to find a way forward with the ExoMars mission.
Since sanctions were imposed, Roscosmos has withdrawn its personnel from Europe's spaceport in French Guiana, forcing all Soyuz missions to be put on hold, five of which were due to be for the ESA.
"A robust launch manifest for ESA missions’ launch needs, including for spacecraft originally planned for launch by Soyuz from Kourou, will be submitted to Member States," the ESA wrote.
The latest blow to space cooperation comes just a day after former NASA astronaut Scott Kelly dropped his feud with head of Roscosmos Dmitry Rogozin after the US agency said it could endanger the future of the ISS.
Rogozin had called Kelly a "moron" and insinuated he was suffering from Alzheimer's.
Kelly has since returned a Russian space medal awarded for multiple Soyuz flights, due to the Ukraine invasion.