ISRO reschedules Proba-3 mission launch after ‘anomaly’; what is the glitch, what is the new lift-off time?

CHENNAI: The much-anticipated launch of the Proba-3 mission aboard the PSLV-C59 rocket has been postponed to tomorrow, December 5, due to a last-minute ‘anomaly’ identified during the pre-launch preparations. It was scheduled to launch at 4:06 pm today (December 4) from the Satish Dhawan Space Centre in Sriharikota, Andhra Pradesh.

The technical glitch was spotted by scientists at the European Space Agency (ESA) in one of the satellites of the PSLV-C59-mission, ahead of the lift-off, following which they requested the Indian Space Research Organisation (ISRO) to reschedule it to December 5, an ISRO official told PTI.

The ISRO has now rescheduled the launch to 4:04 pm tomorrow. Earlier, the rescheduled time was mentioned as 4.12 pm.

Explaining the anomaly, Director General of ESA, in a statement on social media platform X said, “During Proba3’s pre-launch preparations at the Satish Dhawan Space Centre in India, an anomaly in the redundant propulsion system of the Coronagraph Spacecraft occurred. This propulsion system is part of the attitude and orbit control subsystem of the satellite and used to maintain orientation and pointing in space.

The anomaly is currently under detailed investigation. The use of a software solution by the mission control team at @ESA’s ESEC centre at Redu, Belgium is being evaluated to allow a launch on Thursday 5 December at 11:34 CET (10:34 GMT, 16:04 local time). #Proba3”

All you need to know about the Proba-3 mission

The PSLV-C59 is a joint initiative between ISRO and NewSpace India Limited (NSIL), the commercial arm of ISRO which would launch client vehicles. The NSIL secured the order from European Space Agency (ESA) for its latest launch, which would be a 'technology demonstration' mission.

The Proba-3 (Project for Onboard Autonomy) consists of a double-satellite in which two spacecraft would fly together as one, maintaining precise formation down to a single millimetre to study the sun's outer atmosphere. The mission objective is to demonstrate precise formation flying and the two spacecraft — Coronagraph (310kgs) and Occulter (240kgs) — would be launched together in a stacked configuration, ISRO said. 'Probas' is a Latin word, meaning 'Let's try'.

The Bengaluru-headquartered space agency is using its proven Polar Satellite Launch Vehicle (PSLV) for the mission. The 44.5 metre tall 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.

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 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.

For ISRO, this launch would provide key insights on taking up scientific experiments on the Sun after its maiden mission--Aditya-L1 which was successfully launched in September 2023.

(With inputs from PTI)