ISRO Set to Launch ESA's Proba-3 Sun Observation Mission

The Indian Space Research Organisation (ISRO) ready to launch the European Space Agency's (ESA) Proba-3 Sun observation mission. Scheduled for Wednesday, the launch will take place from the First Launch Pad (FLP) at Satish Dhawan Space Centre (SDSC-SHAR), Sriharikota. The PSLV-C59/Proba-3 mission is a testament to ISRO'sproven expertise and its growing contributions to global space exploration.

The Proba-3 mission is designed to study the Sun's faint corona closer to the solar rim. It is an in-orbit demonstration (IOD) mission of the ESA, aiming to demonstrate precise formation flying. The mission comprises two spacecraft - the Coronagraph Spacecraft (CSC) and the Occulter Spacecraft (OSC) - which will be launched together in a stacked configuration aboard the PSLV-XL rocket. This marks the 61st flight of PSLV and the 26th using the PSLV-XL configuration.

The spacecraft will create a 144-metre-long instrument known as a solar coronagraph, enabling scientists to study the Sun's corona, which is difficult to observe due to the brightness of the solar disk. The high-altitude orbit will help the satellites perform formation flying for about six hours at peak altitude, where Earth's gravitational influence is reduced. This will lower propellant consumption and allow for optimal positioning control.

The Proba-3 satellites were flown to the Chennai airport from Liege in Belgium, following which they were transported to the spaceport at Sriharikota. The PSLV-C59 vehicle will carry the Proba-3 spacecraft into a highly elliptical orbit as a dedicated commercial mission of NewSpace India Limited (NSIL).

The mission is ISRO's collaboration with international space agencies. The 25-hour countdown started at 3:08 PM on Tuesday, with all preparatory work underway at Sriharikota's spaceport. ISRO Chairman Dr S. Somnath offered prayers at the Sri Chengalamma Parameshwari Temple in Sullurpet, revered by Telugu and Tamil devotees, ahead of the highly anticipated Proba-3 satellite launch.

The mission will place the Proba-3 satellite into a high-altitude orbit, reaching approximately 60,000 kilometres above Earth. Scientists from ISRO and European countries are working together to ensure the satellite is accurately positioned in its designated orbit. The total mass that the launch vehicle will be lifting off is around 320 tonnes.

The CSC is equipped with the 3DEES (3D Energetic Electron Spectrometer) to study electron fluxes in Earth's radiation belts, contributing to advancements in space weather research. They will work together to produce fake solar eclipses as part of Proba-3, the first precision formation flying mission in history.

During the countdown, propellant filling operations–solid and liquid propellants–will be carried out in the four-stage vehicle. The satellites have been integrated into the payload fairing of the Polar Satellite Launch Vehicle. Maintaining the correct position in the shadow requires a precise formation flying capability, down to a single millimetre of precision.

The Proba-3 mission is a shining example of international collaboration and a proud milestone in India's space journey. It is the first mission to launch from India since the Proba-1 mission in 2001, underscoring deepening space collaboration. The mission also showcases the importance of international collaborations in advancing space research.