Successful Indian GSLV Launch Features Domestic Upper Stage

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PARIS — India’s Geosynchronous Satellite Launch Vehicle (GSLV) rocket on Aug. 27 placed India’s GSAT-6 telecommunications satellite into geostationary transfer orbit in the second consecutive success for the vehicle’s domestically built cryogenic upper stage, the Indian Space Research Organisation (ISRO) said.

The launch follows the rocket’s January 2014 inaugural success, which came after a 2010 failure and an aborted launch.

“We have demonstrated that what happened on Jan. 5, 2014, was no fluke. All the systems performed normally and the various intricacies of the cryogenic engine have been understood,” ISRO Chairman Kiran Kumar said after the launch.

R. Umamaheswaran, ISRO’s mission director for the flight, said the next GSLV would be made ready for a launch in June or July 2016. He said the cryogenic stage, which has been upgraded since the January 2014 inaugural success, brings the GSLV rocket’s performance up to 2,500 kilograms into geostationary transfer orbit.

ISRO officials have said that perhaps one GSLV rocket per year could be made available for commercial launches as GSLV enters the global market alongside India’s PSLV vehicle, designed mainly for Earth observation satellites heading to polar low Earth orbit.

With the advent of electric propulsion aboard commercial telecommunications satellites for both in-orbit station-keeping and orbit-raising to final geostationary position, the future market for a 2,000-kilogram-class vehicle has greatly improved.

What remains unclear is when ISRO and its commercial arm, Antrix Corp., will be able to establish a production and launch rhythm sufficient to bring launch costs down to a commercially competitive level, as they have done with the PSLV. Also unclear is the current U.S. policy on permitting U.S.-built satellites or satellite components to be exported to India for commercial missions.

The U.S. government in the past couple of years has granted export licenses for ostensibly commercial Earth observation missions, but only in the form of waivers to the current regulations. As China has found out, a ban on U.S. satellite exports is a de facto exclusion from the global commercial launch market.

The U.S. issue is not related to India’s missile-launch policy but rather to the Indian government’s refusal to commit to an agreement on commercial-launch pricing.

What did seem clear after the Aug. 27 flight is that the domestically built cryogenic engine is no longer a monkey on ISRO’s back, as it has been for years. Previous versions of the GSLV have employed a Russian-built cryogenic upper stage.

“The naughty boy has now been transformed into the most adored boy of ISRO,” Umamaheswaran said.

Operating from the Satish Dhawan Space Centre SHAR, the GSLV carried the 2,117-kilogram GSAT-6 satellite into a transfer orbit that ISRO said was close to the intended drop-off point – a perigee of 170 kilometers, an apogee 35,975 kilometers and an inclination of 19.95 degrees relative to the equator.

The focus of attention was the cryogenic stage, but GSAT-6 includes several features of its own that represent firsts for ISRO, which built the satellite.

Notable among them is a 6-meter-diameter, unfurlable S-band antenna with five spot beams covering the Indian subcontinent. It is the largest satellite antenna ever built by ISRO. ISRO announced Aug. 30 that the S-band antenna had successfully deployed in orbit.

The antenna was scheduled to be deployed after the satellite completed its orbit-raising maneuvers on its way to its operating position at 83 degrees east longitude in geostationary orbit. The satellite also carries a C-band payload.