Proba-3 is such an ambitious mission that it needs more than one single spacecraft to succeed. In order for Proba-3’s Coronagraph spacecraft to observe the Sun’s faint surrounding atmosphere, its disk-bearing Occulter spacecraft must block out the fiery solar disk. This means Proba-3’s Occulter ends up facing the Sun continuously, making it a valuable platform for science in its own right.

Proba-3 is scheduled for launch on a PSLV-XL rocket from Satish Dhawan Space Centre in Sriharikota, India, on Wednesday, 4 December, at 11:38 CET (10:38 GMT, 16:08 local time).