The launch of the PROBA-3 mission is planned for mid 2023.
The highly elliptical orbit of PROBA-3 (600 x 60530 km at 59° inclination) have the period of 19.63 hours.
For science operations (about twice a week), the two spacecraft acquire flight formation about 3 hours before the apogee and keep it for 6 hours, without relying on guidance from the ground. During this observation period, the disc of the Sun as viewed from the Coronagraph Spacecraft is masked by the Occulter Spacecraft, 144 m apart, making possible the observations of the corona. Other special configurations are possible for special purposes (e.g. calibration).
For the rest of the orbit, the spacecraft are left to fly free in a configuration intended to avoid collision.