Why GSLV preferred over PSLV.

Why GSLV preferred over PSLV.

Question:-Chandrayaan–I, India’s first unmanned lunar probe was launched using a PSLV-XL rocket by Isro in 2008.while Chandrayaan–Ii will be launched by GSLV so What is the potential significance of GSLV and GSLV Mark III over PSLV?

- During the first attempt made by ISRO with the Mars Orbiter, it turned toward the Polar Satellite Launch Vehicle (PSLV), a rocket with incredible track record. It was initially thought that it would not be easy to utilize the PSLV for the task since it may not be too powerful.

- After the first successful attempt ISRO will need to dispatch bigger and far advanced spacecraft in the coming years. So for the future missions, they will turn to Geosynchronous Satellite Launch Vehicle (GSLV) which can lift heavier spacecraft compared to PSLV.

- To utilize GSLV and GSLV Mark III, the cryogenic engines need to have multi start capability so they can shut down after one burn and undergo a period of coasting and restart. As a prerequisite for its final injection on a trajectory to Mars, it was extremely crucial for placing a spacecraft in the correct orbital orientation around the earth. These improved systems will eventually make way for larger spacecrafts to move into orbits that are closer to Mars, with lander and rover operations on the planet's surface.

- Starting, shutting and restarting a cryogenic engine in space is a complicated affair. The restart ability has not been demonstrated with the GSLV cryogenic engine. Once the initial engine level tests are done for mark III , the restart capability introduction can be looked at.

- ISRO has designed and ground-tested a ‘Payload Assist Module’ that used a liquid-propellant engine that powers the PSLV’s fourth stage. The initial idea of developing the module was so that the GSLV could launch Russia's Global Navigation Satellite System (GLONASS) satellites. However the proposal that ultimately did not materialize. The module could enhance the capabilities of GSLV or GSLV Mark III to send probes to Mars.

Facts and figures:

- The Geosynchronous Satellite Launch Vehicle was primarily developed to launch INSAT class of satellites into Geosynchronous Transfer Orbits.

- PSLV has launched various satellites for historic missions like Chandrayaan-1, Mars Orbiter Mission, Space Capsule Recovery Experiment, IRNSS etc.

- Mars Orbiter was launched November 5, 2013.