On a cloudy afternoon this week in Kazakhstan, a robot set out on a seven-month, 500-million-kilometre trip to Mars.
Once it arrives, the robot will split into two parts. The first is a lander that will ensure a future rover can land safely. The second part will skim the thin Martian atmosphere, looking for traces of chemicals such as methane that might indicate life on the surface.
I've always wondered if there's life on other planets and this mission might help answer the question... Are we alone?