Now, following more finetuning and testing, the team has achieved the desired precision, making Proba-3 the world’s first-ever precision formation flying mission.

The mission relies on several innovative technologies, many of which are technology demonstrations developed through ESA’s General Support Technology Programme (GSTP). “To do something that has never been done before, we needed to develop new technologies,” notes Esther Bastida Pertegaz, Proba-3 systems engineer.

“The formation flying is performed when the spacecraft are more than 50 000 km above Earth,” explains Raphael Rougeot, Proba-3 systems engineer.

“Here, the Earth’s gravity pull is small enough, so that very little propellant is needed to maintain the formation. Then the formation is broken and needs to be acquired again over the next orbit, in a repeated cycle.”