 "Isro to launch Proba-3 mission satellites on December 4 from Sriharikota")
The Indian Space Research Organisation (Isro) is set to launch the PSLV-C59/Proba-3 mission on Wednesday at 4:06 pm from the Satish Dhawan Space Centre in Sriharikota, Andhra Pradesh.
This mission will use the Polar Satellite Launch Vehicle (PSLV) to place satellites weighing approximately 550 kg into a highly elliptical orbit, capturing the attention of space enthusiasts worldwide.
Proba-3: ESA's in-orbit demonstration
The mission will deploy the European Space Agency’s (ESA) Proba-3, described as an “In-Orbit Demonstration (IOD) mission”. This will mark the 61st flight of the PSLV and the 26th using its PSLV-XL configuration, according to ISRO’s recent update on X. The agency stated: "The PSLV-C59/PROBA-3 mission... is set to carry ESA's PROBA-3 satellites (~550 kg) into a highly elliptical orbit."
What is the Proba-3 mission?
PSLV, India’s first launch vehicle featuring liquid stages, is designed to deliver satellites and other payloads into space as per Isro’s requirements. The PSLV’s maiden launch was successfully conducted in October 1994. For this mission, the European team present in India has completed the integration process by safely encasing the spacecraft within the payload fairing, followed by a dress rehearsal for the launch.
Proba-3 is a joint mission aimed at exploring the Sun’s corona, the outermost layer of its atmosphere, which plays a crucial role in understanding solar dynamics and space weather phenomena.
Formation flying and solar eclipses
According to Isro, Proba-3 will feature two spacecraft: the Occulter Spacecraft (OSC) and the Coronagraph Spacecraft (CSC). These spacecraft will launch in a “stacked configuration” and work in tandem to simulate artificial solar eclipses. This mission, the first-ever precision formation flying initiative, will allow the satellites to maintain a 150-metre separation in highly elliptical orbits.
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This configuration facilitates extended solar corona observations — up to six hours — compared to the fleeting natural eclipses. The Occulter will block sunlight, enabling the coronagraph to study solar phenomena that are typically challenging to observe.
PSLV-XL: Boosting mission capabilities
The PSLV-XL variant, equipped with additional strap-on boosters, is known for its enhanced payload capacity. It will launch the combined 550 kg of the Occulter and Coronagraph spacecraft. Isro said the mission will proceed in four stages, with the launch vehicle lifting off with a total mass of around 320 tonnes.
Isro further said that this mission showcases PSLV’s “trusted precision” and underscores international collaboration in space exploration.
India’s growing role in global space missions
This launch not only highlights Isro’s reliability as a launch partner but also underscores India’s expanding influence in international space exploration.
The PSLV-C58 mission, Isro’s previous PSLV launch, successfully placed the XPOSAT satellite into an eastward low-inclination orbit on January 1 this year. XPOSAT, also known as the X-ray Polarimeter spacecraft, was India’s first scientific mission dedicated to studying X-ray polarisation from astronomical sources.