The Geosynchronous Satellite Launch Vehicle (GSLV)-D5, powered by an indigenous cryogenic engine, was successfully launched from the Satish Dhawan Space Centre in Sriharikota on Sunday, putting India in the elite group of nations that can launch heavy satellites. Only a few countries like the US, Russia, France Japan and China have mastered the cryogenic engine technology.The success comes after two back-to-back failures and one aborted mission involving the GSLV.
A cryogenic rocket engine is a rocket engine that uses a cryogenic fuel or oxidizer, that is, its fuel or oxidizer (or both) are gases liquefied and stored at very low temperatures. India had been denied this technology for many years and had to depend on Russian technology for the previous GSLV launches. The launch vehicle, which has the capability of placing 2,000–2,500kg satellites into geosynchronous transfer orbit, will reduce if not completely stop India’s dependence on foreign launch vehicles
At present, Indian satellites of this category are launched by foreign space agencies like Arianespace. The space agency spends around Rs500 crore for the launch of heavyweight satellites by a foreign space agency. However ISRO could launch these satellites onboard its own launch vehicle like the GSLV at nearly half the cost.
A satellite placed in a geosynchronous orbit matches earth’s rotation. A satellite in a geostationary orbit appears stationary, always at the same point in the sky, to ground observers. Communications satellites are often given geostationary orbits, or close to geostationary, so that the satellite antennas that communicate with them do not have to move, but can be pointed permanently at the fixed location in the sky where the satellite appears.
A semi-synchronous orbit has an orbital period of 11 h 58 min. Relative to the Earth’s surface it has twice this period, and hence appears to go around the Earth twice every day. Examples include the orbits of the satellites in the Global Positioning System(GPS).