Tim Peake is set to control a robot rover while orbiting the Earth from space in a pioneering experiment.
The British astronaut will remotely navigate the explorer through a simulated Martian landscape from the International Space Station today.
The experiment, part of the ExoMars project, will take place in a hangar at Airbus Defence and Space in Stevenage.
Major Peake tweeted yesterday: "Looking forward to giving rover Bridget in Stevenage, UK, a test-drive from space."