ISRO successfully launches GSAT-7A for Air Force communication

ISRO's geosynchronous launch vehicle on Wednesday, December 19, successfully injected into orbit the country's latest advanced satellite that will substantially enhance the communication systems of the Indian Air Force.

After a 26-hour countdown, the GSLV-F11, carrying the 2,250kg GSAT-7A, lifted off at 4.10 pm from the second launch pad at Sriharikota, situated about 110 km from Chennai.

Around 19 minutes after lift-off, the GSLV-F11 injected GSAT-7A into the intended orbit. The GSAT-7A will be pushed up further to its final geostationary orbit firing its onboard motors in the days to come. It will be placed in its final geostationary orbit using the onboard propulsion systems.

According to the Indian Space Research Organisation (ISRO), the satellite would take a few days after separation from the launcher to reach its orbital slot.

ISRO scientists broke into cheers as the satellite was injected into orbit.

According to the space agency officials, the advanced communication satellite would facilitate exclusive frequency flight communication for the IAF. It will enable the IAF to link its ground radar stations, its airbases and Airborne Early Warning and Control System (AWACS) planes. The satellite may also control IAF's unmanned aerial vehicles and drones.

This is the second dedicated military communication satellite to be launched. The first, GSAT-7 or Rukmini, was launched in 2013, for use by the Indian Navy.

Earlier the satellites were of dual use, for civilian and defence purposes.

"There is increased demand for satellites from strategic sectors. About six/seven satellites are planned to be built," said a senior ISRO official.

From the Mission Control Centre, ISRO Chairman K Sivan said Wednesday's "successful and safe" launch was the third one in 35 days and came close on the heels of the "grand success" of two missions in November.

The GSLV-F11 successfully injected the "advanced" communication GSAT-7A into orbit, an elated Sivan said, describing the mission as "wonderful." This was the heaviest satellite lifted by the GSLV with indigenous cryogenic stage, he said.

It came with many firsts, including increased propellant loading and other features, the ISRO chief said.

The "cryogenic stage is burnt to depletion to get a supersynchronous transfer orbit to enhance the life of the satellite," he said.

The mission life of the GSAT-7A, built by ISRO, is eight years. It will provide communication in Ku-band over the Indian region.

The advanced communication satellite also came with new technology regarding the antenna to improve the performance, Sivan said.

Its solar panels have been deployed and orbit raising manoeuvres will be done from Thursday morning from Bengaluru, he said.

Wednesday's mission also gave the scientists some anxiety "as the weather god was not very conducive some one week back," Sivan noted.

However, the meteorological team here gave correct predictions, he said and congratulated the ISRO team members behind the successful launch, the last of this calendar year.

"This is the last mission of this year. We are going to initiate the new year with a grand mission soon," he said.

Sivan said the new year would see ISRO taking up challenging launches, including the Chandrayaan-2 moon mission.

The GSLV-F11 is the ISRO's fourth generation launch vehicle with three stages.

Four liquid strap-ons and a solid rocket motor at the core form the first stage of the launch vehicle, while the second stage is equipped with a high-thrust engine using liquid fuel, ISRO said.

The Cryogenic Upper Stage forms the third and final stage of the vehicle.

The seventh launch of 2018 from Sriharikota marks the 69th mission of GSLV-F11 for ISRO.

With this successful launch, India established the performance of its GSLV rocket which in future may fetch orders from third parties for launching their satellites.

India at present puts into orbit foreign satellites for a fee using its lighter rocket, the Polar Satellite Launch Vehicle (PSLV), as its weight carrying capacity is lower.

Revenue for launching a satellites depends on weight of the satellite -- higher the weight, higher will be the revenue.

On November 14, ISRO's GSLV-MkIII-D, which is dubbed by the ISRO as the 'Bahubali' or "fat boy" of Indian rockets, injected into orbit a 3,423 kg communication satellite GSAT-29, the country's heaviest to be put into orbit.

India's earth observation satellite HysIS and 30 other co-passenger satellites from eight countries were launched onboard ISRO's trusted workhorse Polar Satellite Launch Vehicle on November 29.

"This year completed 17 rocket/satellite missions. The next year will have 32 rocket/satellite missions," Sivan told ISRO officials.

The next year's missions include the complex Chandrayaan-2 or the moon mission.