ISRO Reschedules Launch Of Proba-3 Mission To 5 December After Anomaly Detected In The Spacecraft

The launch of PSLV-C59 by the Indian Space Research Organisation (ISRO) has been postponed to Thursday (5 December) due to detection of an anomaly in the European Space Agency's (ESA) PROBA-3 spacecraft.

The launch of the twin satellites for the Proba-3 mission was initially scheduled at 4.08 pm today (4 November) from Satish Dhawan Space Centre (SDSC) in Sriharikota, Andhra Pradesh.

"Due to an anomaly detected in PROBA-3 spacecraft PSLV-C59/PROBA-3 launch rescheduled to tomorrow at 16:12 hours," said ISRO in a statement on X.

The PSLV-C59 is a joint initiative between ISRO and NewSpace India Limited (NSIL).

ESA's Proba Missions

The Proba (PRoject for OnBoard Autonomy) missions are a series of in-orbit demonstration (IOD) missions from the European Space Agency, for demonstrating and validating new technologies and concepts in orbit.

Developed under the General Support Technology Programme (GSTP) of ESA, the Proba missions are based on small satellites, embarking payload and instruments to deliver actual data to users to demonstrate a new capability.

ESA has launched three Proba missions so far — Proba-1 in 2001, Proba-2 in 2009, and Proba-V in 2012.

The Proba-3 Mission

The Proba-3 mission is devoted to the demonstration of technologies and techniques for highly-precise satellite formation flying.

It consists of two small satellites launched together that will separate apart to fly in tandem, to prepare for future multi-satellite missions flying as one virtual structure.

Proba-3 marks the next step in formation flying. As a world first, its two satellites – the Coronagraph spacecraft and the Occulter spacecraft – will maintain formation to a few millimetres and arc second precision at distances of around 150 metres for six hours at a time. 

One satellite features a telescope, kept in the centre of the shadow cast by the other satellite around 150 m away, thanks to an occulter disc. 

Maintaining the correct position in the shadow requires a precise formation flying capability, down to a single millimetre of precision.  

Each Proba-3 satellite is powered through high efficiency solar panels.

When in position the two satellites will be precisely aligned so that the Occulter spacecraft casts a shadow across the Coronagraph space craft.

The satellite called the Occulter Spacecraph (or OSC) features a 1.4-m-diameter occulting disk, which will be kept perpendicular to the direction of the Sun’s light.

This disk will cast a shadow, of about 8 cm width at around 150 m.

The satellite called the Coronagraph (or CSC) hosts a scientific telescope with a 5 cm aperture.

The goal is to maintain, owing to formation flying, the “Coronagraph” aperture within the 8 cm shadow with millimetre accuracy.

This will happen when the two satellites are close to the apogee along their highly elliptical orbit (more than 60 000 km altitude), where Earth's force of gravity is weaker and formation maintenance requires less propellant.   

Proba-3 will be able to study the corona for six hours in every 19hr 36min orbit, a factor of a hundred improvement in uninterrupted study time.    

Also Read: Devendra Fadnavis Set To Become Maharashtra Chief Minister As Mahayuti Leaders Stake Claim To Form Government