By IANS,
New Delhi : Since its first launch in 1994, India’s Polar Satellite Launch Vehicle (PSLV) has so far placed 41 satellites (19 Indian and 22 foreign) into orbit – making it one of the most successful launch vehicles ever worldwide.
* The PSLV was originally developed and operated by the Indian Space Research Organisation (ISRO) to launch its Indian Remote Sensing (IRS) satellites into orbit with the help of Russia. It was then used for launching a variety of satellites.
* The Geo-Synchronous Launch Vehicle (GSLV) project is of an earlier vintage, initiated in 1990 by ISRO to acquire launch capability for geo-synchronous satellites (which seem to be parked above the earth in a particular spot).
* Until then, India also relied on the erstwhile Soviet Union for the launch of heavy satellites.
* GSLV-Mark I&II, is capable of placing the INSAT-II class of satellites, weighing between 2,000 and 2,500 kg, into orbit.
* The GSLV-III is a launch vehicle currently under development by ISRO.
* GSLV-III is conceived and designed to make ISRO fully self-reliant in launching heavier communication satellites of the INSAT-4 class, which weigh 4,500 to 5,000 kg.
* In April 2008, ISRO successfully launched a PSLV with 10 satellites in one go, breaking a world record once held by Russia. A PSLV costs $17 million for each launch.
* The PSLV has four stages, alternately using solid and liquid propulsion systems.
* The GSLV is a three-stage launch vehicle with the first stage being solid (fuel)-propelled, the second liquid-propelled (with hypergolic fuels) and the final stage being liquid propelled as well as with cryogenic fuels.
* A rocket propellant combination is called hypergolic when the propellants spontaneously ignite when they come into contact.
* The GSLV variants improved on the performance of the PSLV with the addition of liquid strap-on boosters and cryogenic fuel required for the final stage.
* Cryogenic fuels require storage at extremely low temperatures in order to maintain them in a liquid state.