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ISRO Launches GSAT-15 from Hired Ariane-5, Two More on Cards

ISRO launched the scheduled communications satellite GSAT-15 on Thursday successfully at 3:04 AM from Kourou in French Guyana in South America using the Ariane-5 rocket launcher of the United states.
The Indian Space Research Organisation (ISRO) has hired Ariane-5, which is also carrying an ARABSAT satellite accompanied with GSAT-15. Today’s mission payloads are placed at:
– Perigee: 246.9 km. for a target of 247.1 km.
– Apogee: 35,884 km. for a target of 35,884 km.
– Inclination: 3.99 deg. for a target of 4.00 deg.
Indigenous GSAT-15 satellite with weight of 3,164 kilograms, costing Rs 278 crore is carrying a suite of 24 transponders for Direct-to-Home (DTH) broadcasting and a GPS-Aided GEO Augmented Navigation (GAGAN) payload operating in L1 and L5 bands, for aircraft navigation. The hiring of Ariane has cost an additional Rs.581 crore for the Indian space agency.
Lofted into a Geosynchronous Transfer Orbit (GTO) minutes after injecting the co-passenger Arabsat-6B (BADR-7) into space, Ariane rocket launcher was hired to for heavy payloads as ISRO is still short of carrying such payloads currently.
The successful launch of GSAT-5 will make India fill the shortage of transponders in space. India is able to cover one-third of satellite requirement capacity now and is still dependent on other nations’ satellites for its satellite system, which is growing at faster pace. With the recent decision on relaxing FDI in non-news channels, the ISRO has to gear up for a larger demand to manufacture communications satellites and the heavy payloads rocket launchers matching the ARIANE-5.
ISRO has already selected Arianespace to launch the next two series of GSAT-17 and GSAT-18 telecommunications satellites on Ariane 5 flights from French Guiana in 2016 and 2017.  These satellites weigh 3,400 kg. at launch each and they will replace currently-operational relay platforms providing key national and military services in multiple frequency bands.
Ariane 5 usually carries two telecommunications satellite payloads and is powered during the initial flight phase by a cryogenic core stage and two solid rocket boosters, followed by a cryogenic upper stage for orbital injection of the payload. It has a capacity of sustaining weight of more than 19,000 kg. at liftoff.
“Launch after launch, we are demonstrating our capability to increase our operational pace while remaining the most reliable solution for all our customers,” said Arianespace Chairman and CEO Stéphane Israël, after the successful launch.

GSAT-15 was the 19th satellite entrusted to Arianespace by ISRO the 18th satellite built by ISRO. Ariane was first commissioned in 1981 to launch the country’s APPLE experimental satellite.

“Today’s launch is ISRO’s 19th mission with Arianespace. In the meantime, ISRO also has launched four French spacecraft using [India’s own] PSLV,” said Dr M Annadurai, Director of the ISRO Satellite Centre. “Thanks to such a long association, our team is quite familiar with working with Arianespace and the support we get from Arianespace in preparing a satellite launch is excellent.”

The other Arabsat-6B (BADR-7) was lofted for Airbus Defence and Space and Thales Alenia Space as part of a turnkey contract with Saudi Arabia-based Arabsat – for which Arianespace has so far launched 8 spacecraft since 1985. Today’s Ariane 5 flight marked the workhorse heavy-lift vehicle’s 69th consecutive success.

Arabsat-6B, which will be renamed BADR-7 once in orbit and weighed some 5,798 kg. at liftoff, is the initial sixth-generation satellite for Arabsat’s fleet – providing broadcast, broadband and telecommunications services over the Middle East, Africa and Central Asia. Airbus Defence and Space supplied its Eurostar E3000 platform and handled satellite integration, while Thales Alenia Space supplied the telecommunications relay payload.

Ariane-5 Specs:
Ariane 5’s core cryogenic stage serves as one of the launcher’s key propulsion systems as it carries a propellant load of 132.27 metric tons of liquid oxygen and 25.84 metric tons of liquid hydrogen to feed the stage’s Vulcain main engine. The Vulcain burns for just under 600 seconds, providing up to 116 metric tons of thrust in vacuum.
The stage has an overall length of 30.5 meters from the Vulcain main engine’s nozzle to the forward (upper) skirt and its dry mass is 12.2 metric tons, and the liftoff mass with its load of cryogenic propellant is 170.3 metric tons. After injecting the satellites, the empty stage re-enters the atmosphere for an ocean splashdown.


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