Launch now scheduled for Thursday 5 December

Not because it is easy but because it is hard: this historic space phrase is pretty much the definition of ESA’s double-satellite Proba-3 mission, which will employ precise formation flying to produce artificial total solar eclipses in orbit, casting a shadow from one spacecraft to the other. No-one has ever flown a mission like this, up until now. But just why is it so hard? Find out in this curtain-raising video trailer.