The European Space Agency (ESA) has begun testing its Proba-3 pair of sun-watching satellites, which will fly in formation to cast a sustained shadow from the disk-faced ‘Occulter’ spacecraft to the ‘Coronagraph’ spacecraft, allowing the observation of the inner layers of the sun’s faint corona. The satellites were completed in the spring and have been shipped to IABG in Germany for testing. The next test stage will be unique to the mission, as the Proba-3 pair will maintain their positions relative to each other down to millimetre-level precision, employing a range of guidance, navigation and control systems. The satellites are due to be flown by a PSLV launcher from India next year.
