ISRO launched successfully two satellites for the Proba-3 mission of the European Space Agency (ESA) on Thursday (December 5). The launch occurred at the Satish Dhawan Space Centre (SDSC) in Sriharikota in Andhra Pradesh at 4.04 PM IST, employing the robust PSLV-C59 rocket in the PSLV-XL configuration, recognized for its dependability and effectiveness. This signified the 61st launch of the Polar Satellite Launch Vehicle (PSLV) and the 26th employing the XL variant, which features six boosters for enhanced power.

Indian Space Research Organisation (ISRO) officials said in X, "Mission Success! The PSLV-C59/PROBA-3 Mission has successfully achieved its launch objectives, deploying ESA’s satellites into their designated orbit with precision. The PSLV-C59/PROBA-3 Mission reflects the dedication of NSIL, ISRO and ESA teams. This achievement highlights India’s critical role in enabling global space innovation".

Minutes before the launch on December 4, ISRO postponed the PSLV-C59/PROBA-3 mission to December 5, 4.04 pm, at the request of the European Space Agency. It was postponed after an irregularity was found in the satellite propulsion system.

Proba-3 mission to study Son’s corona

The Proba-3 mission comprises two satellites. The Coronagraph Spacecraft (CSC) (310kgs) and the Occult Spacecraft (OSC) (240kgs), totalling approximately weighted 550 Kg together. These satellites were sent into space in a stacked arrangement and placed into a highly elliptical orbit. The main objective of the mission is to showcase accurate formation flying, as the two spacecraft keep a distance of 150 meters apart to examine the Sun's corona, its outer atmosphere, which has a much higher temperature than the Sun's surface and is the source of space weather.

The spacecraft will operate together, with the Occulter the solar disk, enabling the Coronagraph to study the corona for research purposes. Proba-3 will provide essential information regarding the Sun's behaviour, enhancing ISRO's previous achievement with the Aditya-L1 mission in 2023 that examined the Sun.

Proba-3 is a mission for demonstrating technology, supported through the General Support Technology Programme. The instruments on the satellites would move near the solar edge for as long as six hours at a stretch, and each craft would complete a roughly 19-hour orbit around the Earth.

India’s critical role in global space innovation

'Probas' is a term derived from Latin, which translates to 'Let us attempt'. The goal of the mission is to showcase accurate formation flying, and the two spacecraft within the satellites will be launched together in a stacked arrangement once the target orbit altitude is achieved. PSLV-C59 stands at 44.5 meters tall and represents its 61st launch, being the 26th flight of the PSLV-XL variant typically utilized for deploying heavy satellites. Following the lift-off, the two satellites, Coronagraph and Occulter, would embark on an 18-minute trip to attain their intended orbit. Once the two spacecraft achieve the necessary preparatory conditions, they will operate 150 meters apart, functioning as a single large satellite structure in tandem. This arrangement allows the 'Occulter spacecraft to obscure the solar disk of the Sun, facilitating the 'Coronagraph' to examine the solar corona or its surrounding atmosphere for scientific analysis.