To make things difficult, BepiColombo is more than 100 million kilometres away from Earth, travelling at a velocity of 54 km/s with respect to the Sun, with signals taking 350 seconds (about six minutes) to travel from us to the mission, at the speed of light.

“Because of the remarkable precision of measurements from our network of ground stations and antennas all over the globe and the continuous efforts of the Flight Dynamics Navigation Team, our current knowledge of BepiColombo’s position is accurate to about 500 metres, and we know its velocity to the nearest millimetre per second,” explains Frank Budnik, Flight Dynamics Manager of BepiColombo at ESA’s ESOC Operations Centre.