Isro’s GSLV-D6 with indigenous cryo engine successfully places GSAT-6 in orbit
SRIHARIKOTA: Indian Space Research Organization (Isro) on Thursday cleared all doubts on its cryogenic capabilities, successfully launching the Geostationary Satellite Launch Vehicle (GSLV-D6), placing GSAT-6, a 2,117kg communication satellite in orbit.
This marks the second successful GSLV launch using an indigenous cryogenic engine. The first launch, on April 15, 2010 was a failure, followed by the second one on January 5, 2014 which was a success.
GSLV-D6 carrying GSAT-6 lifted off from Sriharikota spaceport at 4.52pm as scheduled. This was the ninth flight of the Geostationary Satellite Launch Vehicle.
Around 17 minutes after liftoff, the rocket injected GSAT-6 into a Geosynchronous Transfer Orbit (GTO), making the mission a success.”We have understood the intricacies of a cryogenic engine. The rocket performed normally,” said Isro chairman A S Kiran Kumar.
GSAT-6 provides communication through five spot beams in S-band and a national beam in C-band for strategic users. One of the advanced features of GSAT-6 satellite is its S-Band Unfurlable Antenna of 6 m diameter. This is the largest satellite antenna realized by Isro and it has a life of nine years. GSAT-6 will be used mainly for military purposes.
GSLV-D6 vehicle was configured with all its three stages including the cryogenic upper stage (CUS) similar to the ones successfully flown during the previous GSLV-D5 mission in January 2014, an Isro statement said.
The metallic payload fairing of GSLV-D6 had a diameter of 3.4 m. The overall length of GSLV-D6 was 49.1 mass with a lift-off mass of 416 tonne.
The cryogenic upper stage on GSLV-D6 was designated as CUS-06. A cryogenic rocket stage is more efficient and provides more thrust for every kilogram of propellant it burns compared to solid and earth-storable liquid propellant rocket stages.
The cryogenic stage is technically a very complex system compared to solid or earth-storable liquid propellant stages due to its use of propellants at extremely low temperatures and the associated thermal and structural challenges. Oxygen liquefies at -183-degrees celsius and Hydrogen at -253-degrees celsius. The propellants, at these low temperatures, are to be pumped using turbo pumps running at around 40,000 rpm.
The main engine and two smaller steering engines of CUS together develop a nominal thrust of 73.55 kN in vacuum. During the flight, CUS fires for a nominal duration of 720 seconds. S-band telemetry and C-band transponders enable GSLV-D6 performance monitoring, tracking, range safety/flight safety and preliminary orbit determination (POD).
credit : timesofindia