Satellite Launching Vehicles

India’s first experimental satellite launch vehicle, the Satellite Launch Vehicle-3 (SLV-3), was an all-solid, four-stage vehicle weighing 17 tonnes and standing at a height of 22 meters. It had the capability to place 40 kg class payloads in Low Earth Orbit (LEO).The inaugural flight of SLV-3, conducted in August 1979, achieved partial success. Subsequent launches occurred in July 1980, May 1981, and April 1983, deploying Rohini satellites equipped with remote sensing sensors.The successful completion of the SLV-3 project paved the way for advanced launch vehicle initiatives, including the Augmented Satellite Launch Vehicle (ASLV), Polar Satellite Launch Vehicle (PSLV), and Geosynchronous Satellite Launch Vehicle (GSLV).

ASLV

The Augmented Satellite Launch Vehicle (ASLV) Programme aimed to triple the payload capacity to 150 kg for Low Earth Orbits (LEO), surpassing that of SLV-3. Drawing on experience from SLV-3 missions, ASLV served as an affordable intermediate vehicle to showcase and validate critical technologies essential for future launch vehicles. These technologies included strap-on technology, inertial navigation, bulbous heat shield, vertical integration, and closed-loop guidance.

PSLV

The Polar Satellite Launch Vehicle (PSLV) represents the third generation of launch vehicles developed by India. It stands as the country’s first launch vehicle to incorporate liquid stages. Following its inaugural successful launch in October 1994, the PSLV has emerged as India’s reliable and versatile workhorse launch vehicle, boasting 39 consecutive successful missions as of June 2017. Over the period from 1994 to 2017, the PSLV has been responsible for launching 48 Indian satellites and 209 satellites for international customers.

The Polar Satellite Launch Vehicle (PSLV) is a four-stage launch vehicle.
The first stage consists of a large solid rocket motor.
The second stage is powered by an earth-storable liquid stage.
The third stage utilizes a high-performance solid rocket motor.
The fourth stage comprises a liquid stage with engines.
The PSLV has successfully launched two spacecraft: Chandrayaan-1 in 2008 and the Mars Orbiter Spacecraft in 2013.

Vehicle Variants and Launch Capability

PSLV-CA

No. of strap-on motors : Nil
Payload capability to SSPO (600 km) : 1019 Kg

PSLV- DL

No. of strap-on motors : Two
Payload capability to SSPO (600 km) : 1257 Kg

PSLV-QL

No. of strap-on motors : Four

PSLV-XL

No. of strap-on motors : Six
Payload capability to SSPO (600 km) : 1673 Kg
Payload capability to sub GTO (284 x 20650 km) : 1425 Kg
Payload capability to SSPO (600 km) : 1523 Kg

GSLV

The Geosynchronous Satellite Launch Vehicle (GSLV) project was initiated in 1990 with the objective of acquiring an Indian launch capability for geosynchronous satellites. GSLV uses major components that are already proven in the Polar Satellite Launch Vehicle (PSLV) launch vehicles in the form of the S125/S139 solid rocket booster and the liquid-fueled Vikas engine.

GSLV-Mk II stands as India’s largest fourth-generation launch vehicle, characterized by the following key features:

It comprises three stages, each with distinct propulsion systems.
The first stage is powered by a 138-tonne solid rocket motor, augmented by four liquid strap-ons.
The second stage utilizes a single Vikas engine.
The third stage features the CE-7.5 cryogenic engine, developed under the Cryogenic Upper Stage Project (CUSP) by the Liquid Propulsion Systems Centre, marking India’s first foray into cryogenic engine technology.
Additionally, GSLV-Mk II includes four liquid-engine strap-ons.
GSLV’s maiden flight took place on April 18, 2001.
GSLV-Mk II exhibits impressive payload capacities:
It can transport INSAT-class communication satellites weighing up to 2500 kgs to Geostationary Transfer Orbit (GTO).
It is capable of carrying heavy satellites weighing up to 5000 kgs, or multiple smaller satellites, into Low Earth Orbit (LEO).