: A milestone crossed in the making of a new cryogenic rocket engine set the stage for the first flight of the country’s most powerful satellite launcher to date, the GSLV-Mark III. The cryogenic stage and the entire launch vehicle’s readiness is closer to fruition after the engine, technically called CE20, passed the ‘high altitude flight acceptance test’ lasting about 25 seconds at Mahendragiri in mid-December.

The Indian Space Research Organisation (ISRO) plans to fly its new launch vehicle powered by this new engine around March, and send the 3,200 kg GSAT-19 communication satellite to space on it. The launch was earlier slated for December 2016. MkIII, when it completes trials and commences functioning in the coming years, will double ISRO’s lifting power for communications satellites to 4,000 kilos.

Vital stage

In a few days from now, the rocket’s complete cryogenic third stage, replete with fuel tanks and systems built around the engine, will undergo its qualifying test, S. Somanath, Director of ISRO’s Liquid Propulsion Systems Centre (LPSC), Thiruvananthapuram, told The Hindu.

“LPSC has designed and developed the CE20 engine. We are assembling the entire cryogenic stage, which is ready for flight. It will be sent to Sriharikota in a month’s time,” he said.

The cryogenic stage is vital for a GSLV rocket as it gets its final and biggest push in space from this stage; it can take a big communications satellite to higher reaches of 36,000 km above ground. The C25 cryogenic stage was approved at an estimated ₹600 crore as part of the overall ₹2,500-crore MkIII launcher project.

“Realising the CE20 engine was our target in order to achieve India’s capability to lift a four-tonne satellite to GTO (geostationary transfer orbit, around 36,000 km high),” Mr. Somanath said.

“We have been longing for this for a few years. MkIII will be the future work horse after the PSLV,” he said.

MkIII becomes ‘operational’ or ready for regular work after two successful launches in a row. ISRO plans to have one MkIII launch in a year, and the next one is planned for December this year.

Over 200 tests

About the qualification of the CE20, Mr. Somanath said it was the culmination of over 200 tests, some repeated and taking a week to 10 days each. The project picked up pace after early tests on a full-scale engine last year. The space agency has set up a ₹450-crore High Altitude Test (HAT) Facility at the ISRO Propulsion Complex for testing the engine in conditions similar to an actual launch in space.

Calling it an important milestone ahead of the MkIII launch, ISRO said the HAT test of December met all the test objectives.

“The testing of the engine in the HAT facility has helped in finalising the engine start and shut down sequence for the flight,” Mr. Somanath added.

The vehicle’s first two qualified stages are already in Sriharikota, namely the solid-fuelled S200 and the liquid-fuelled L110 stages.