What is the Main Difference Between PSLV and GSLV?

By BYJU'S Exam Prep

Updated on: November 9th, 2023

The main difference between PSLV and GSLV is that the PSLV has four stages that alternate between solid and liquid fuels, while GSLV has three stages, with only the first stage using solid fuel. The Indian Space Research Organization, or ISRO, developed the PSLV (Polar Satellite Launch Vehicle) and GSLV (Geosynchronous Satellite Launch Vehicle) as rocket launch systems for placing satellites into orbit.

Main Difference Between PSLV and GSLV

As the oldest of the two, the GSLV even incorporates some of the PSLV’s innovations into its design. The rocket itself is another area where PSLV and GSLV differ from one another. The satellite-launch vehicles (rockets) created by ISRO are the PSLV (Polar Satellite Launch Vehicle) and GSLV (Geosynchronous Satellite Launch Vehicle).

  • The primary purpose of PSLV is to launch “earth-observation” or “remote-sensing” satellites into Sun-Synchronous circular polar orbits at altitudes between 600 and 900 kilometres.
  • The earth’s remote sensing satellites travel in a pole-to-pole orbit (at about 98 deg orbital-plane inclination).
  • When the angle between the line connecting the satellite’s centre and the Sun remains constant throughout the orbit, an orbit is said to be sun-synchronous.
  • These orbits are also known as “Low Earth Orbits (LEO)” due to their sun-synchronism characteristics, which allow the satellite’s onboard camera to capture images of the earth under the same sun-illumination conditions during each of its repeated passes over the same area on the ground.
  • This makes the satellite useful for monitoring the earth’s resources.


The PSLV is used to launch satellites with lower lift-off masses, up to about 1400 kg, into the elliptical Geosynchronous Transfer Orbit, as well as remote sensing satellites into Sun-synchronous polar orbits (GTO).

  • The PSLV is a four-stage launch vehicle powered by solid rocket motors in the first and third stages and liquid rocket engines in the second and fourth.
  • Strap-on motors are also used to increase the thrust produced by the first stage.
  • Depending on how many strap-on boosters are used, the PSLV can be classified as a core-alone version (PSLV-CA), a PSLV-G, or a PSLV-XL.
  • The GSLV’s primary mission is to launch communication satellites into geosynchronous transfer orbit, which is typically 250 x 36000 km elliptical (GTO).
  • By igniting its built-in onboard engines, the satellite in GTO is further lifted to its eventual goal, Geo-synchronous Earth orbit (GEO), of approximately 36,000 km height (and zero degrees inclination on the equatorial plane).

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