Proba-3 lifted off on its PSLV-XL rocket from Satish Dhawan Space Centre in Sriharikota, India, on Thursday, 5 December, at 11:34 CET (10:34 GMT, 16:04 local time). The mission was launched using this Indian launcher because it needed to be placed in a highly elliptical orbit extending more than 60 500 km from the ground.

After integration and testing was completed at Redwire Space in Belgium, Proba-3 was transported to India to be prepared for launch.

The latest member of ESA’s family of in-orbit demonstration missions, Proba-3 is in fact two spacecraft being launched together, which will separate in orbit to begin performing precise formation flying, precise to a single millimetre, about the thickness of an average fingernail. To prove their performance, Proba-3 has been devoted to an ambitious scientific goal. The pair will line up precisely with the Sun 150 m apart so that one casts a precisely controlled shadow onto the other.

By blocking out the fiery disc of the Sun, Proba-3’s ‘Occulter’ spacecraft will mimic a terrestrial total solar eclipse, to open up views of the Sun’s faint surrounding atmosphere, or ‘corona’, which is a million times fainter than its parent star. Proba-3’s second ‘Coronagraph’ spacecraft hosts the optical instrument that will observe the solar corona.

If Proba-3’s initial commissioning phase goes to plan then the spacecraft pair will be separated early in the new year to begin their individual check-outs. The operational phase of the mission, including the first observations of the corona through active formation flying, should begin in about four months.

Proba-3 was led for ESA by Sener in Spain, overseeing a consortium of 14 ESA Member States and Canada including Airbus Defence and Space in Spain manufacturing the spacecraft and Redwire Space in Belgium responsible for the spacecraft avionics, assembly and operations. CSL in Belgium produced Proba-3’s ASPIICS coronagraph Spacebel in Belgium developed the onboard and ground segment software with GMV responsible for the formation flying system and flight dynamics.