Proba-3 is ESA’s precision formation flying mission, aligning two satellites in orbit to open up a prolonged view of the Sun’s normally invisible solar corona. The two satellites will be launched together in stack configuration by PSLV-XL launcher from India’s Satish Dhawan Space Centre. The pair will be placed in a highly elliptical 60 000 km altitude orbit. They will be commissioned together before separating to begin their formation flying. Through exquisite, millimetre-scale, formation flying, the dual satellites will accomplish what was previously a space mission impossible: cast a precisely held shadow from one platform to the other, in the process blocking out the fiery Sun to observe its ghostly surrounding atmosphere on a prolonged basis. The satellites will employ a suite of positioning technologies to hold their positions relative to one another, as if they were a single rigid ‘coronagraph’ instrument across a distance of approximately 150 m in length. This formation flying will take place for around six hours per 19 hour 36 minute orbit, at the top of the orbit to minimise gravitational, magnetic and atmospheric perturbations. During the rest of the orbit the pair will fly in passive formation around each other.

Access the Proba-3 mission footage.