Isro flags off second stage of GSLV launch vehicle to Sriharikota

Isro on Saturday announced that the second stage of it's GSLV launch vehicle was flagged off by Chairman V Narayanan recently from the Isro Propulsion Complex (IPRC), Mahendragiri, to the launch complex at Sriharikota.

The Directors of Isro Propulsion Complex (IPRC) and Vikram Sarabhai Space Centre (VSSC) also participated in the flag off ceremony which was held on March 24, it said.

"This liquid stage is earmarked for the upcoming mission of GSLV (GSLV-F16), that will launch the Nasa-Isro Synthetic Aperture Radar (NISAR) satellite. The launch campaign activities for this mission have already commenced at Sriharikota in the first week of April 2025," Isro said, in a statement.  Also, a short duration hot test of the semicryogenic engine was successfully conducted at the test facility in Isro Propulsion Complex (IPRC) at Mahendragiri in Tamil Nadu, the space agency said on Saturday.

This ignition test conducted on April 24 is the second milestone after the successful first hot test on March 28, 2025, that was a major breakthrough in the testing of the Semicryogenic engine test programme, it said.

In a statement, Isro said, this test, the Engine Power Head Test Article, encompassing all engine systems except the thrust chamber, was subjected to a hot test for a duration of 3.5 seconds, that validated the engine start-up sequence.

"During the test, the engine was successfully ignited and operated up to 60 per cent of its rated power level, demonstrating stable and controlled performance," it said.

According to Isro, these tests are part of a planned series of evaluations designed to validate the design integrity and performance of critical subsystems, including the low-pressure and high-pressure turbo pumps, pre-burner and associated control systems.

The results provided crucial data to finalise the operational sequencing of the full Semicryogenic engine.

"Further qualification tests are scheduled to comprehensively validate the engine system, ultimately paving the way for its induction into Isro's launch vehicles," it added.