ISRO takes big leap with GSLV launch; India becomes 6th nation to develop cryogenic engine

SRIHARIKOTA: Indian space engineers enjoyed the fruits of two decades of tireless work on Sunday as the indigenous cryogenic engine performed flawlessly and injected a 1.9-tonne satellite into a Geosynchronous Transfer Orbit (GTO) with high precision.

The rest of the three-stage Geostationary Satellite Launch Vehicle (GSLV), which had seen several glitches and aborted launches over the last few years, also performed exactly as required.

Over the next three days, the GSAT-14 satellite will be manoeuvred over the subcontinent into a geosynchronous orbit 36,000 km above the earth. Precisely 16 minutes and 55 seconds into the launch, as the satellite separated from the final cryogenic stage of GSLVD5, it was an emotional moment for everybody at the Indian Space Research Organisation (ISRO).

Current and former engineers at ISRO even think that this is the agency’s finest moment, much more significant commercially and for the development of indigenous technology than the Mars Orbiter mission.

Without a performing GSLV, ISRO’s future programmes would have been seriously affected. ISRO chairman K Radhakrishnan said: “Cryogenic technology is quite complex and only a few in the world have mastered it.” ISRO got its measure of technology for the smaller Polar Satellite Launch Vehicle (PSLV) quickly. It has had 25 textbook PSLV launches and is now widely considered the best vehicle in the world in its class.


However, the GSLV had only two successful flights out of seven, which were with Russian cryogenic engines. The US had forced Russia to deny India the technology and ISRO had to content itself with seven cryogenic engines but no technology transfer.

It is the first successful flight of the indigenous cryogenic engine. “This shows that we can master any technology,” said S Ramakrishnan, director of the Vikram Sarabhai Space Centre (VSSC) in Thiruvananthapuram. The PSLV does not have a cryogenic engine and can only put small satellites, weighing just over one tonne, into geosynchronous orbit.

A cryogenic engine, which uses liquid oxygen at -253 degrees Celsius and liquid hydrogen at -183 degrees Celsius, can develop the thrust needed in the final state of the rocket to put satellites, weighing two tonnes or more, into a geosynchronous orbit. Mastering this technology is essential for any space power as launching heavier satellites requires cryogenic engines even in the lower stages of the rocket. “The 1,000 seconds of the GSLV flight was achieved with 1,000 days of dedicated work,” said K Sivan, GSLV mission director. Only five others have cryogenic technology: the US, Russia, Europe, China, and Japan.

The repeated failures of the GSLV had baffled ISRO engineers as the rocket was very similar; even simpler in some senses, compared to the ever-reliable PSLV. But critical components, many of them developed by Indian industry, had failed in the GSLV. Three years ago, ISRO put everything behind the GSLV and conducted a thorough review.

It created special facilities and put a rigorous test regime in place. No ISRO launch vehicle has been tested as thoroughly as the GSLV-D5. “We have done whatever was possible,” said MC Dattan, director of the Liquid Propulsion Systems Centre in Thiruvananthapuram, “And so we were very sure of the success of GSLV.” ISRO has nine large satellites scheduled to be launched in the near future. They include the GSAT-6, 6A, 7A and GSAT 9, two Geostationary Information Satellites (GSATs) for remote sensing, and a few more communication satellites.

It is also beginning to work on the Chandrayaan-2. None of these can be launched with the PSLV. If the GSLV hadn’t worked, ISRO would have had to look for a launch vehicle abroad for all of them, pushing up the costs.