CHENNAI, Sept 7: The Indian Space Research Organisation (ISRO) today said with two back-to-back successful missions carrying indigenous cryogenic stage, the Geosynchronous Satellite Launch Vehicle (GSLV) has matured into a reliable launch vehicle and paved the way for its future operational missions, providing India with self-sufficiency in launching higher capacity satellites into the Geosynchronous Transfer Orbit (GTO).
ISRO, on its website on a topic titled ‘GSLV SAGA’, said while technical criticalities of the complex GSLV system have been overcome, challenges are being taken up for improving the payload capability from the present 2,117 kg to the design target of 2,500 kg.
”Detailed studies are in progress, addressing the various ways of achieving this target”, it said. ISRO’s next GSLV Mission, designated as GSLV-F05, was targeted for launch in July 2016. It will carry the 2200kg INSAT-3DR Meteorological Satellite.
GSLV-F09 was planned in May 2017 to launch the GSAT-9 satellite while the prestigious Chandrayaan-2 Mission was designated for launch by GSLV in 2017-18 time frame.
All the future launches of GSLV will be with the indigenous cryogenic stage.
GSLV was well on its way towards international and commercial operations, the release said.
”Work is already in progress on the joint effort with NASA for the launch of NISAR satellite into a polar orbit by 2020-21”, it said.
”This mission will demonstrate the versatility of the GSLV for launch into various orbits. Enquiries are also coming in for commercial launches from various countries”, ISRO said.
The release said the 49 m tall GSLV with a lift-off mass of 416 tons, was designed to launch two ton class of satellites into the GTO. The three-stage GSLV adopts the flight-proven solid and liquid stages of Polar Satellite Launch Vehicle (PSLV) and a cryogenic upper stage.
The first stage comprises a solid propellant core motor and four liquid propellant strap-ons. The second stage is powered by a single liquid propellant engine. The third stage is a Cryogenic Stage with 12 tons of propellant loading.
The GSLV has basically evolved from the rugged flight-proven PSLV.
The solid propellant core motor of GSLV, called S139, is derived from the PS1 core stage of PSLV. Four liquid fuelled strap-ons, called L40, are clustered around the core stage.
The second stage of the GSLV, designated as GS2, and the four L40 stages, use earth-storable liquid propellants and are derivatives of the PSLV’s second stage.
The third stage of GSLV is the cryogenic stage, which uses liquid Hydrogen as fuel and liquid Oxygen as oxidiser. Liquid Oxygen is stored at -183 Deg C while liquid Hydrogen is stored at -253 Deg C in two separate tanks.
The major subsystems of cryogenic engine are the combustion chamber, gas generator, turbo pump, start up system.
In spite of the complexity and challenges, these fluids are preferred due to their ability to produce maximum thrust for every kilogram of propellant and the cryogenic engines are the most efficient engines in use for launch vehicles.
The release said since ISRO did not have the cryogenic technology, the initial launches of GSLV were flown with procured Russian Cryo Stage.
At the same time, efforts were on to develop India’s own cryo engine and Stage.
The current version of GSLV has a payload Fairing of 3.4 metre diameter made of Aluminum Alloy. This Fairing houses the satellite during the launch phase through the atmospheric regime.
The vehicle is equipped with an Inertial Navigation and Guidance System for computing the inertial position and guiding the vehicle from lift-off to satellite injection.
The Digital Auto Pilot and the Closed Loop Guidance scheme ensure the required attitude (orientation) manoeuvre and guided injection of the satellite. GSLV had its maiden launch on April 18, 2001. Subsequently, there were three more successful launches with GSLV-D2, GSLV-F01 and GSLV-F04. EDUSAT, India’s first satellite dedicated for education was launched in GSLV-F01 mission.
All these missions were conducted with Russian Cryo Stage.
The first indigenously developed Cryo Stage, launched in GSLV-D3, could not accomplish the mission due to its turbo pump failure.
After a thorough understanding of the problem and implementing the required changes, exhaustive tests including High Altitude Test of the engine were conducted.
Following this, GSLV-D5 was successfully launched on January five, 2014, with the indigenously developed cryogenic stage which placed the 1982 kg GSAT-14 satellite into a precise GTO. The consistency in the performance of the vehicle, especially the Cryo Stage, was established with the recent spectacular success of GSLV-D6 carrying GSAT-6 satellite on August 27 this year. (UNI)
Follow our WhatsApp channel