ISRO completes static test of a strengthened PSLV third stage after anomalies on two missions

India's space agency has fired the reworked third stage of its Polar Satellite Launch Vehicle on the ground. ISRO said the static test of the stage, known as PS3, was carried out successfully on November 12, 2026, at the Static Test Facility of the Satish Dhawan Space Centre in Sriharikota. It is the stage ISRO links to anomalies on two missions, PSLV-C61/EOS-09 and PSLV-C62/EOS-N1. The agency said more tests are planned once the data have been analyzed and reviewed, and it gave no date for the rocket's return to flight.

What ISRO says it changed

After the two anomalies, ISRO says, it reviewed the whole configuration of the stage: its design margins, the criteria for accepting raw materials, the way the motor is assembled and the quality checks used until now. The changes it lists are a modified nozzle configuration to give more design margin; stronger mechanical interfaces, with redundancy added to the sealing systems; and revised procedures for accepting raw materials, for assembly and for non-destructive testing during integration and transport. The motor fired on November 12 is a new version of the PS3 stage built to those changes, according to the agency.

The release does not give the length of the firing or any performance figures, and it does not say what caused the anomalies. In February, ISRO said only that a national-level expert committee was reviewing the reason for the anomaly in the PSLV vehicle. The November release does not mention that committee or its findings.

Where the third stage sits in the rocket

ISRO's brochure for PSLV-C62 describes a four-stage rocket 44.4 meters tall with a liftoff mass of 260 metric tons, flying in the PSLV-DL version with two solid strap-on motors. The third stage, listed there as HPS3, held 7.66 metric tons of HTPB-based solid propellant. In the planned flight sequence it was to ignite 264.56 seconds after liftoff and separate at 494.72 seconds, which by our arithmetic is about 230 seconds of flight, before the liquid-fueled fourth stage was to take over.

The missions behind the rework

PSLV-C62 was set to lift off on January 12, 2026, from the First Launch Pad at Sriharikota, as the 64th flight of the PSLV, according to ISRO. It was the ninth dedicated commercial mission of NewSpace India Limited (NSIL), carrying the EOS-N1 Earth observation satellite for a customer and 15 co-passenger satellites from Indian and international customers. Among them was KID, the Kestrel Initial Technology Demonstrator, a small prototype re-entry capsule from a Spanish startup that was meant to come down in the South Pacific Ocean. ISRO's mission page now carries a brief note saying the flight met an anomaly near the end of the PS3 stage and that a detailed analysis had begun.

The PSLV had flown 63 times before that mission, ISRO says, carrying Chandrayaan-1, the Mars Orbiter Mission, Aditya-L1 and Astrosat, and in 2017 it launched 104 satellites on a single flight, which ISRO describes as a world record. ISRO calls the rocket its workhorse.

What comes next

ISRO says further tests will follow its analysis of the November 12 data, and it has not said when the PSLV will fly again. Its other launcher work continues: the cryogenic engine for the next GSLV mission passed its flight acceptance test on November 5, as we reported on November 11.