ISRO reschedules Proba-3 launch to Thursday after detecting anomaly

Sriharikota (Andhra Pradesh): The Indian Space Research Organisation (ISRO) has failed to launch PROBA-3 spacecraft of the European Space Agency (ESA), its dedicated commercial mission after detecting an "anomaly". The agency announced that the spacecraft which is dubbed as the world's first initiative of its kind would be launched on Thursday. ISRO had originally planned the launch at 4.08 pm on Wednesday from the spaceport here. 

"Due to an anomaly detected in PROBA-3 spacecraft PSLV-C59/PROBA-3 launch rescheduled to tomorrow at 16:12 hours," the space agency said in an update minutes ahead of the lift-off. 

The mission to study sun's outer atmosphere
'Probas' is a Latin word, which refers to 'Let's try'. The mission objective is to demonstrate precise formation flying and the two spacecraft - 'Coronagraph' and 'Occulter' would be launched together in a stacked configuration, ISRO said.
The Bengaluru-headquartered ISRO is using its dedicated workhorse Polar Satellite Launch Vehicle (PSLV) for the mission. The 44.5 metre tall rocket after travelling for about 18 minutes 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 ESA said.

The significant objective of the mission is formation flying in precision and to study the Sun's outer atmosphere. This pattern of (blocking the solar disk of the sun) formation occurs during solar eclipses and that too for a few minutes for scientists to study. However, the European Space Agency said with Proba-3, the mission would be able to create 'solar eclipses on demand.'

The two satellites would fly together as a 'large rigid structure' in space to prove formation flying technologies and rendezvous experiments, the ESA said.
"The mission will demonstrate formation flying in the context of a large-scale science experiment. The two satellites will together form an approximately 150-metre long solar coronagraph to study the Sun's faint corona closer to the solar rim than ever before it has been achieved," it said.

ISRO would be facilitating the launch while European Space Agency scientists would take up study on the mission, post it reaching the desired orbital conditions. 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.

The Proba-3 mission follows the earth observation satellite Proba-1 launched by ISRO in 2001 and Proba-2 in 2009. The European Space Agency had also launched the Proba-V mission in 2013.

Europe has made significant progress in multi-satellite missions in the past including the 'Automated Transfer Vehicle' mission which demonstrated precision down to a few centimetres when docking with the International Space Station.Sweden's Prisma Mission also demonstrated formation flying for brief periods, maintaining centimetre level accuracy across tens of metres, the ESA said.