The countdown has begun for ISRO’s highly anticipated commercial mission to launch the European Space Agency’s (ESA) Proba-3 spacecraft, scheduled for liftoff on December 4. The mission, a technology demonstration, is being facilitated by NewSpace India Ltd, ISRO’s commercial arm, which secured the contract for this cutting-edge launch.

“The 25-hour countdown commenced at 3:08 PM on Tuesday, and preparations for the launch are well underway,” an ISRO official informed PTI.

Proba-3, a pioneering mission described as the world’s first of its kind, consists of a dual-satellite system. The two spacecraft will operate in tandem, flying with extreme precision down to a millimeter to investigate the Sun’s outer atmosphere. The name "Proba," derived from Latin, translates to "Let’s try," reflecting the mission's innovative spirit.

The two satellites, named Coronagraph and Occulter, will launch in a stacked configuration aboard ISRO’s dependable Polar Satellite Launch Vehicle (PSLV), embarking on its 61st mission and the 26th flight of its PSLV-XL variant. Liftoff is set for 4:08 PM on December 4 from the first launch pad at Sriharikota.

Standing 44.5 meters tall, the PSLV is expected to deliver the 550 kg Proba-3 spacecraft into the intended orbit approximately 18 minutes post-launch. Once deployed, the satellites will separate and maintain a synchronized distance of 150 meters, functioning as a unified system. This unique configuration allows the Occulter to block the Sun’s disk, enabling the Coronagraph to closely study the Sun’s corona—the area surrounding the solar surface—where space weather originates.

ESA scientists emphasized the significance of Proba-3, stating that the mission will create “solar eclipses on demand,” a feat typically only possible during rare natural events. The spacecraft’s capability to study the Sun’s corona closer to the solar rim than ever before offers unprecedented opportunities for scientific exploration.

In addition to its groundbreaking science objectives, Proba-3 also aims to demonstrate precision formation flying. The satellites will simulate a rigid structure in orbit, advancing technologies for future multi-satellite missions and rendezvous experiments.

This launch builds on ISRO’s growing expertise in solar observation missions, following the success of its Aditya-L1 mission in September 2023. The Proba-3 mission also aligns with ESA’s history of advancements in satellite technology, including previous Proba missions and precision maneuvers demonstrated by Europe’s Prisma and Automated Transfer Vehicle missions.

The Proba-3 mission represents a significant milestone for both ISRO and ESA, combining advanced engineering with cutting-edge scientific objectives. As ISRO’s PSLV prepares to soar into space, it carries the promise of unlocking new insights into our Sun while advancing the frontiers of satellite technology.