PROBA-3 Mission: From blocking sun’s orbit with ‘occulter’ to studying corona, know secrets ISRO, ESA to unveil

The Indian Space Research Organisation (ISRO) will launch the Polar Satellite Launch Vehicle (PSLV)-C59 /Proba-3 mission from the Satish Dhawan Space Centre in Sriharikota, Andhra Pradesh, on Wednesday.

The mission will entail the Polar Satellite Launch Vehicle (PSLV)-C59 carrying satellites weighing approximately 550 kg in a highly elliptical orbit. The PROBA-3 mission is an “In-Orbit Demonstration (IOD) mission” by the European Space Agency (ESA), ANI reported.

Posting about the anticipated launch on X, the space organisation said, Liftoff Day is Here! PSLV-C59, showcasing the proven expertise of ISRO, is ready to deliver ESA’s PROBA-3 satellites into orbit. This mission, powered by NSIL with ISRO’s engineering excellence, reflects the strength of international collaboration. A proud milestone in India’s space journey and a shining example of global partnerships. Liftoff: 4th Dec 2024, 16:08 IST. Location: SDSC-SHAR, Sriharikota. Join NSIL, ISRO, and ESA as history unfolds!”

Role of “occulter”

The mission consists of 2 spacecraft, namely the Coronagraph Spacecraft (CSC) and the Occulter Spacecraft (OSC), which will be launched together in a “stacked configuration” (one on top of another).

ISRO said the mission objective is to demonstrate precise formation flying, and the two spacecraft, ‘Coronagraph’ and ‘Occulter,’ will be launched together in a stacked configuration.

The PSLV is on its 61st flight and the 26th of the XL variant. After travelling for about 18 minutes, it is slated to place the 550kg Proba-3 satellites into a desired orbit, PTI reported.

After reaching the initial orbital conditions, the two satellites would fly 150 metres apart (as one large satellite structure) in tandem so that the ‘Occulter’ spacecraft would block out the solar disk of the sun, enabling the Coronagraph to study the corona of the Sun or the surrounding atmosphere, for scientific observation.

“The corona, much hotter than the Sun itself, is where space weather originates and a topic of widespread scientific and practical interest,” the European Space Agency said.

PSLV is a launch vehicle that helps carry satellites and other payloads to space,according to ISRO’s requirements. This launch vehicle is India’s first to be equipped with liquid stages. The first PSLV was launched successfully in October 1994.

The PSLVC-59 will have four stages of launch, according to ISRO. The total mass which the launch vehicle will be lifting off is around 320 tonnes.

The Space organisation also highlighted how this launch mission also exemplifies the “trusted precision” of the PSLV and collaboration with other agencies. 

After lifting-off at the scheduled time of 4.08 pm on Wednesday, the satellites are expected to reach High Earth Orbit and would have a 19.7 hour orbital period with 60,530 km of apogee (farthest point from earth) and 600 km perigee (closest point to earth), PTI reported.

(With inputs from agencies)