Proba-3 will constantly measure Sun's energy output

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 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.