The second developmental test flight of India’s Geosynchronous Satellite Launch Vehicle, GSLV, was successfully carried out this evening May 8, 2003 from Satish Dhawan Space Centre – SHAR, Sriharikota, about 100 km north of Chennai, marking a major milestone in the Indian space programme. With this launch, India has moved further in establishing its capability to launch geo-synchronous communication satellites.
The 414 tonne, 49 m tall GSLV, carrying an experimental, 1825 kg, satellite, GSAT-2, lifted off from Sriharikota at 4.58 pm IST. About seventeen minutes after lift off, GSAT-2 was successfully placed in an orbit of 180.04 km perigee (nearest point to earth) and an apogee (farthest point to earth) 36,000 km with an orbital inclination of 19.2 degree with respect to the equator.
As the count down for the launch smoothly proceeded, at 4.8 seconds before the count zero, the four liquid propulsion strap on stages, each carrying 42 tonne of propellant, were ignited. At count zero and after confirming the normal performance of the liquid propulsion strap on motors, the mammoth 138 tonne solid propellant first stage motor was ignited and GSLV blazed into the evening sky. The first stage burned for 105.03 seconds while the liquid propulsion strap on stages continued thrusting up to 148.4 seconds from lift-off taking the vehicle to an altitude of 69 km . At the end of the first stage burn- out, the GSLV had reached a velocity of 2.8 km per second.
The second stage, which carried 39.3 tonne of liquid propellant, ignited 1.6 seconds before the burn out of the first stage strap-on motors. This stage burned for 140 seconds taking the vehicle to an altitude of 131 km and increasing its velocity to 5.4 km per second. During the second stage operation, when the vehicle was at an altitude of 115 km and had cleared the dense atmosphere, the payload fairing that protects the spacecraft from the aerodynamic heating, was discarded.
After the separation of the second stage at 292.5 seconds from lift off, the cryogenic stage was ignited. The cryogenic stage, which carried 12.6 tonne of liquid hydrogen and liquid oxygen, burned for 704 seconds taking the satellite and vehicle equipment bay to an altitude of 206 km and increasing the velocity to 10.2 km per second as required for placing the satellite in geosynchronous transfer orbit. The cryogenic stage which was procured from Russia and interfaced with ISRO developed electronics, was separated from the spacecraft at about 1013.4 seconds from lift off. After the spacecraft separation, the cryogenic stage was reoriented and passivated to avoid any collision with the satellite.
All through the flight, the vehicle was guided by the inertial navigation and guidance systems. The performance data of the GSLV was telemetered to the ground stations in Sriharikota, Port Blair and stations at Brunei and Biak in Indonesia which were networked with SHAR Centre.
The first signals acquired from the GSAT-2 received at the ground stations at Biak indicate normal performance. GSAT-2 carries four C-band transponders, two Ku-band transponders and a Mobile Satellite Service Payload. Besides the communication payload, it carries four scientific payloads — Total Radiation Dose Monitor (TRDM) to compare the estimated radiation doses inside the satellite with the directly measured radiation doses using a Radiation Sensitive Field Effect Transistor (RADFET), Surface Charge Monitor (SCM) to indicate the state of the charging environment in the vicinity of the spacecraft, Solar X-ray Spectrometer (SOXS) to study the solar flare emission in 4 KeV-10 MeV energy range using state of the art semiconductor devices & Phoswich Scintillation Detector and the Coherent Radio Beacon Experiment (CRABEX) to investigate the spatial structure, dynamic and temporal variations of Ionosphere and several aspects of equatorial electrodynamics.
GSAT-2 is being tracked, monitored and controlled from MCF, Hassan. During the initial phase of operation, MCF also utilises INMARSAT Organisation’s ground stations at Beijing (China), Fucino (Italy) and Lake Cowichan (Canada). The satellite’s orbit is being precisely determined by continuous ranging from the participating Telemetry Tracking and Command (TTC) ground stations. In the coming days, the orbit of GSAT-2 will be raised to its final geo-stationary orbit using its Liquid Apogee Motor (LAM). Subsequently, the solar arrays and the antenna will be deployed. The satellite will be finally positioned at its designated orbital slot of 48 deg East longitude.
Most of the GSLV hardware including motor cases, inter-stages, heat shield, engine components and electronic modules were built by the Indian industry. About 150 industries, both public and private sector were involved. Several educational and academic as well as R&D institutions have assisted in the realisation of the vehicle. The cryogenic upper stage was supplied by Russia, while the complex electronics which controls the functioning of the stage was developed by ISRO.
GSLV is the most technologically challenging project undertaken so far under the Indian space programme. It is the culmination of efforts of a large number of scientists, engineers and technicians, for over a decade. The second test flight, which has revalidated the various systems of the vehicle and the improvements carried out since the successful first launch, heralds a significant step forward in operationalising the GSLV. Having already established indigenous capability through PSLV for launching IRS class of remote sensing satellites, the GSLV, when commissioned, will make the Indian space programme a self-reliant one, while tuning it towards national development.
