As the ESA knows all too well, landing on Mars is the hard part. In 2016, the space agency watched as its EXOMARS Schiaparelli lander crashed into the Red Planet's crust at more than 300 kph. That static module was designed to demonstrate and test out the rover's landing system. Which is why Oxia (a site that mimimizes the touchdown risks) is a sure-fire bet. The "abundant clays" in its surface materials also suggest that water once flowed there. Equipped with a drill that can probe up to 2 metres of depth, the rover will inspect Oxia's sediments for signs of life.

Despite losing its lander, the ExoMars mission completed its first leg by placing a trace gas research and communication satellite into Mars orbit in 2016. If all goes to plan, its droid will land on the Red Planet in 2020. The ESA and Russia's Roscosmos space agency will announce its destination a year prior.