The 29-hour countdown for the lift-off of the Geo-synchronous Satellite Launch Vehicle (GSLV-D3), which began at 11.27 a.m. on Wednesday, is progressing smoothly, according to S. Satish, spokesman, the Indian Space Research Organisation (ISRO). If there is no hold-up in the countdown, the rocket will soar from its launch pad at Sriharikota at 4.27 p.m. on Thursday. The vehicle, being powered by a totally indigenous cryogenic engine for the first time, will put an advanced communication satellite, GSAT-4, in orbit.
“A successful flight will give India a coveted status among the space-faring nations in the world and total self-reliance in all areas of launch vehicle technology,” said Mr. Satish.
The previous five GSLV flights from Sriharikota from 2001 to 2007 used the Russian cryogenic engines. The GSLV-D3 vehicle is 49 metres tall and weighs 419 tonnes. It is a three-stage rocket. The core first stage is powered by solid propellants. Around this core stage are four strap-on motors powered by liquid propellants. The second stage again uses liquid propellants. The third upper stage is propelled by the indigenously made cryogenic engine. Filling of the second stage and the four strap-on booster motors with liquid propellants will be completed during the countdown.
“Besides, the filling of the cryogenic engine with liquid hydrogen and liquid oxygen will continue till almost the end of the countdown. This is to prevent loss of cryogenic fluids due to evaporation,” said Mr. Satish.
Certain mandatory checks of the vehicle and charging of the batteries in both the rocket and the satellite would be done during the countdown.
The GSAT-4 weighs 2,220 kg. It carries a communication payload called Ka-band transponder for wide-band multimedia services, e-commerce and high bandwidth Internet. The navigation payload named the GPS-aided Geo-Augmented Navigation (GAGAN) system will help commercial aircraft to land accurately in runways during inclement weather.
