Keeping an orbiting satellite on track is no easy feat

When Miguel Serrano first entered the field of spacecraft flight dynamics almost two decades ago, he was faced with the challenge of explaining his job to his mother.

“She thought that I was part of the team in a control room surrounded by displays, red and green lights, headsets, and people looking troubled,” he said. 

Although she wasn’t wrong, over the years, his time sitting on-console in a mission control room represents a small percentage of his whole time working as Flight Dynamics Engineer – only about six months total. What he does the rest of the time may be less flashy but is equally important for the success of a satellite mission.

Since Serrano joined EUMETSAT in December 2019, he has been busy preparing to take control of the first of the Meteosat Third Generation satellites, MTG-I1. He will do this once the Launch and Early Orbit Phase has been successfully completed and the satellite has arrived at its orbit 36,000 km above the Earth. As a flight dynamics engineer, he is part of a team responsible for determining and predicting the trajectory of the satellite and which direction it will face as it orbits the planet in order to keep it where it needs to be to achieve the mission objectives.

This is tricky due to a number of forces – known as perturbations – that push a satellite off its desired course. The Earth’s gravitational attraction is one such perturbation, which is further complicated by the shape of our planet, which is more potato than sphere. This causes the Earth’s gravitational field to be uneven, and so a satellite is pulled more or less at different positions along its orbit. The gravity of the sun and moon also throw a satellite off its ideal orbit, as does sunlight, which can deflect a satellite when it bounces off its surface.