ESA’s Proba-3 mission, led by Sener, ready for launch after final tests of its two satellites

In a final test before its shipping to its Indian launch site, ESA’s eclipse-making double-satellite Proba-3 mission has received commands from its science team and transmitted images back, exactly as it will operate in orbit.

Led by Sener in close collaboration with an industrial team made up of a broad consortium of more than 29 companies from 17 countries, Proba-3 will demonstrate the feasibility of high-precision formation flight between satellites in space. Sener is the prime contractor for the mission and is responsible for both the flight and ground segments.

Proba-3 is an extremely technically and scientifically ambitious mission. Through exquisite, millimetre-scale, formation flying, its dual satellites will accomplish what was previously a space mission impossible: one platform will cast a precisely held shadow onto the other, in the process blocking out the fiery Sun to observe its ghostly surrounding atmosphere on a prolonged basis.

The last in a series of five ‘System Validation Tests’ for the mission involved scientists at the Royal Observatory of Belgium in Brussels sending payload operation requests to the mission’s control centre at ESA ESEC, the European Space Security and Education Centre, across the country at Redu.

The control centre processed these requests then sent telecommands to the science instruments aboard the Proba-3 spacecraft, currently located in a cleanroom in Kruibeke, to manage the requested scientific observations in a fully automated fashion.

Now its testing is complete, Proba-3 will now be shipped to the Satish Dhawan Space Centre in India on 21 October for a planned launch by PSLV-XL launcher on 29 November.

Its latest test spanned 12 hours in all, replicating part of Proba-3’s highly elliptical 19.5-hour orbit around Earth, with its formation flying for observing the solar corona taking place over a six-hour period around apogee, meaning the top of its 60 000 km orbit.

The two satellites’ formation flying will take place on a fully autonomous basis, but the testing included the sending of commands to science instruments for both in-flight calibration scenario and nominal scientific observation, as well as the update of some commands to be replaced with others. That latter functionality provides flexibility to the scientists to quickly react to exceptional solar events.

The only element of Proba-3’s ground segment not involved in the SVT testing is the actual ground stations dotted around the globe that will maintain contact with the satellites during each high-climbing orbit: Santiago in Chile, Yatharagga in Australia, Maspalomas on Gran Canaria and Villafranca near Madrid.

Made up of Coronograph and Occulter satellites, Proba-3 is the latest in an ESA family of experimental minisatellites dating back to 2001, the name coming from the Latin for ‘Let’s try!’.