Full Form of PSLV and GSLV

In India, there are many active space launch vehicles, including PSLV and GSLV. These vehicles carry spacecraft to space. Each vehicle has its functionality and purpose. Different space vehicles are used for different purposes.

What is PSLV?

The full form of PSLV is a Polar Satellite Launch Vehicle. It is a launcher that carries the spacecraft to space. It is a four-stage launch vehicle. In the first and third stages, solid rocket motors are used, while in the second and third stages, liquid rocket motors are used.

PSLV is the first Indian vehicle equipped with liquid stages. PSLV vehicle has launched many Indian and Foreign satellites Chandrayaan-1 was one among those.

Chandrayaan-1, which traveled to the moon in 2008, and the Mars Orbiter Spacecraft, which traveled to Mars in 2013, were launched using PSLV.

Since 1993, PSLV has completed 50 missions with a massive success rate.

PSLV can accommodate a variety of payload configurations. It can launch satellites into Low-Earth Orbit (LEO) with a weight of 1750 kilograms (about 3858.08 lb) and into sun-synchronous orbit (SSO) with a weight of 1425 kilograms (about 3141.58 lb).

“The workhorse of ISRO” is the title given to PSLV because it consistently delivers satellites into low earth orbits.  Due to its reliability, PSLV has also used to launch satellites into Geosynchronous and Geostationary orbits.

History of PSLV:

In 1982, the Indian Space Research Organization (ISRO) decided to build a cost-efficient and reliable space vehicle that should have the capability of placing satellites into polar orbits. For earth observation and remote sensing missions' Polar orbits provide global coverage. Therefore, the Indian Space Research Organization (ISRO) decided to build the PSLV project.

The development of PSLV involved three phases: research, design, and testing. ISRO management encountered several technical challenges during PSLV development. After many years of struggle by ISRO engineers, the first prototype of PSLV, PSLV-D1, was constructed.

On September 20, 1993, the first division of PSLV (PSLV-D1) was launched in Satish Dhawan Space Center, Srihari Kota, India. However, it did not have a high success rate. ISRO developed many features and finally developed a successful PSLV version in October 1994.

Since 1994, it has become the most versatile launch vehicle offering cost-effective and attracting many international customers. PSLV has successfully completed 50 versions to date, boasting a success rate of more than 95%. The most recent version is PSLV-C48.

Versions of PSLV:

ISRO has developed various versions and variants of the PSLV over the years, making improvements from version to version.

The versions of PSLV are:

• PSLV-G: The initial variant of PSLV, PSLV-G stands for PSLV-Generic, launched in 1993. It has four stages that use liquid and solid systems. It can launch 1,678 kg (about 3699.35 lb) to 622km (about 386.49 mi) into a Polar orbit and Sun-synchronous orbit.
• PSLV-CA: The PSLV-CA model was developed on April 23, 2006. PSLV-CA stands for PSLV-Core Alone. It was developed due to the increasing demand to launch smaller satellites into polar and sun-synchronous orbits. This variant has a reduced payload to accommodate smaller satellites. It can launch 400 kg (about 881.85 lb) less than the standard version. It can launch 1,100 kg (about 2425.08 lb) to 622 km (about 386.49 mi) into Polar and Sun-synchronous orbits.
• PSLV-XL: PSLV-XL is the improved version of standard PSLV. PSLV-XL stands for PSLV-extra Large. PSLV-XL is like PSLV-G, but it can accommodate heavier payloads and higher energy emissions. It is the 3rd stage PSLV, which features enlarged strap-on boosters. On December 29, 2005, PSLV-XL was launched. The first use of PSLV-XL was during the Chandrayan-1 launch. It can launch 1800kg (about 3968.32 lb) to 600km (about 372.82 mi) to sun-synchronous orbit and 1,750 kg (about 3858.08 lb) to 622km (about 386.49 mi) to low Earth orbit.
• PSLV-DL: PSLV-DL stands for PSLV-Dual Launch. It was launched to enable the launch of 2 smaller satellites simultaneously. It has a special payload adapter to accommodate multiple satellite payloads. The first use of PSLV-DL was on January 24, 2009. It can launch 1257kg (about 2771.21 lb) to 600km (about 372.82 mi) to a sun-synchronous orbit.
• PSLV-QL: PSLV-QL stands for Quick launch. It was developed to reduce the turnaround time gap between two missions and streamline the launch process. The first use of PSLV-QL was on April 1, 2019. It can launch 1,523 kg (about 3357.64 lb) to 600km (about 372.82 mi) to sun-synchronous orbit.
• PSLV-3S: The original plan for PSLV-3S called for removing the second liquid stage and six strap-on boosters to create a three-staged version of PSLV. It can launch 500 kg (about 1102.31 lb) to 550 km (about 341.75 mi) to low Earth orbit.

What is GSLV?

The full form of GSLV is Geosynchronous Satellite Launch Vehicle. GSLV is a launch vehicle developed in India. It is the largest space vehicle and a fourth-generation vehicle developed by ISRO. GSLV was invented to launch heavy payloads into Geostationary orbits. It is also used for weather monitoring, communication, and navigation satellites.

Unlike PSLV, which was designed to launch satellites into polar and sun-synchronous orbits, GSLV was designed to launch satellites into higher orbits with heavier payloads. GSLV is a three-stage space vehicle and has solid, liquid, cryogenic propulsion systems.

The first stage of GSLV contains a solid rocket booster, which provides the initial thrust during liftoff. The second stage has a liquid fuel engine that can accelerate the vehicle into space. The third stage is the crucial component, containing a cryogenic engine that uses liquid hydrogen and liquid oxygen as propellants. GSLV uses cryogenic propellant technology because cryogenic engines provide higher efficiency and performance than liquid or solid propulsion systems. This cryogenic engine will carry heavy payloads over longer distances.

GSLV has launched many successful satellites, including the Chandrayaan-1 lunar mission and weather satellites. Its success rate is more than 80%.

History of GSLV:

In the late 1980s, there was a huge demand for launching weather, communication, and navigation satellites into geostationary orbits. But there were no such space vehicles. So, ISRO decided to take the initiative to build GSLV.

The development of GSLV began in the early 1990s. During this time, the ISRO engine is focused on building a launch vehicle capable of utilizing solid and liquid propulsion systems.

On April 18, 2001, GSLV made its maiden flight carrying an experimental payload. However, the mission was set back due to the failure of the cryogenic upper stage. It failed to reach its destination orbit. After this failure, ISRO decided to build a better GSLV. However, the subsequent missions also faced the same failures. GSLV has experienced many technical issues, and the success rate of the vehicle was also very low.

In January 2014, the GSLV-D5 mission (Communication satellite) was a huge success. After this success ISRO has made remarkable progress and enhanced GSLV reliability and performance.

Versions of GSLV:

ISRO has launched various versions and variants of GSLV over the years. It made improvements from version to version.

The versions of GSLV are:

GSLV Mk III-G: This specific configuration is intended for the launch of crewed spacecraft, such as the Indian Gaganyaan mission. It has extra safety measures and provisions for life support systems, crew modules, and other parts meant for humans. GSLV Mk III-G will greatly aid India's goals for crewed space exploration and human spaceflight missions.

GSLV Mk I: The first version of the GSLV series is GSLV MK I, alias GSLV Mark I. It is a three-stage configuration consisting of solid and liquid propulsion systems. It includes liquid-fueled missiles and strap-on boosters. This version was mainly used for developmental flights and to test new technologies. It can launch 1,500 kg (about 3306.93 lb) to 35,786 km (about 22236.39 mi) to a geostationary transfer orbit.

GSLV Mk II: The GSLV MK II, alias GSLV Mark II, is an advanced version of GSLV MK I. It has developed a cryogenic upper stage that utilizes liquid hydrogen (LH2) and liquid oxygen (LOX) propellants. GSLV MK II has been enhanced by increasing its payload capacity and performance. It can launch 2,200 kg (about 4850.16 lb) to 35,786 km (about 22236.39 mi) to a geostationary transfer orbit.

GSLV Mk III: The GSLV MK III alias GSLV Mark III. GSLV MK III is named LVM3 (launch vehicle Mark-3). This is the most advanced version among all the versions of GSLV. It has a more powerful cryogenic upper stage and the largest payload capacity. It can launch 4,000 kg (about 8818.48 lb) to geostationary transfer orbits and 10,000kg (about 22046.2 lb) to lower Earth orbits (LEO), a distance up to 35,786 km (about 22236.39 mi).

GSLV Mk III-M1: The operational configuration of the GSLV Mk III is represented by the GSLV Mk III-M1 variant. To increase performance and r liability, it combines enhancements and alterations based on testing and developmental flights. Several payloads, including communication satellites, navigation satellites, and scientific missions, have been launched into orbit using the GSLV Mk III-M1. It can launch 4,000 kg (about 8818.48 lb) to geostationary transfer orbits and 10,000kg (about 22046.2 lb) to lower Earth orbits (LEO), distance up to 35,786 km (about 22236.39 mi).