British astronaut Tim Peake is used to doing difficult experiments every day on board the International Space Station, but he's just had to tackle possibly one of the trickiest yet.
Tim had to direct a rover here on Earth while he was 250 miles up in space.
Major Peake's mission was to get the robot across a sandpit, made to be like the surface of the Mars, and into a cave to look for targets.
The plan is for astronauts to do this when rovers are sent to the Red Planet in the future.
So how did he do? Have a watch of the video to find out.