Evolution of ISRO rockets: History and Timeline

Evolution of ISRO rockets: History and Timeline

The Indian Space Research Organisation (ISRO) has proved itself to be a pioneer in the global space industry.

It has undoubtedly played a pivotal role in reshaping India’s image as an emerging leader and a tough competitor for numerous space agencies across the world. 

From producing marvels who have shown successful results internationally to generating milestones in aerospace, aerodynamics, research and development and the like has made it evident that ISRO is indeed the torchbearer for the innumerable space missions which it has been a part of. 

The ongoing technological advances pertaining to rapidly launching space missions or the upcoming fabricated plan of actions have been of keen interest to the space explorers, space wanderers and scientists.

It has deeply fuelled the curiosities of people all around the world! So here we present a list of ISRO’s intricately designed launch vehicles which have given their contribution in space exploration.

Sounding Rockets

ISRO Sounding Rockets

First successful launch: 1963

Current status: Decommissioned

Sounding rockets are one or two stage solid propellant rockets used for probing the upper atmospheric regions and for space research and analysis.

They also serve as easily affordable platforms to test or prove prototypes of new components or subsystems intended for use in launch vehicles and satellites.

With the establishment of the Thumba Equatorial Rocket Launching Station (TERLS) in 1963 at Thumba, a location close to the magnetic equator, there was a quantum jump in the scope for aeronomy and atmospheric sciences in India. The launch of the first sounding rocket from Thumba near Thiruvananthapuram, Kerala on November 21, 1963, marked the beginning of the Indian Space Programme.

Sounding rockets made it possible to probe the atmosphere using rocket-borne instrumentation. The first rockets were two-stage rockets imported from Russia (M-100) and France (Centaure).

While the M-100 could carry a payload of 70 kg to an altitude of 85 km, the Centaure was capable of reaching 150 km with a payload of approximately 30 kg.

ISRO started launching indigenously manufactured sounding rockets from 1965 and the experience gained  brought immense value to master solid propellant technology. In 1975, all sounding rocket activities were consolidated under the Rohini Sounding Rocket (RSR) Programme. RH-75, with a diameter of 75mm was the first truly Indian sounding rocket, which was followed by RH-100 and RH-125 rockets. 

Currently, three versions are offered as operational sounding rockets, which cover a payload range of 8-100 Kg and an apogee range of 80-475 km.

Satellite Launch Vehicle


First successful launch: 1980

Current status: Decommissioned

Satellite Launch Vehicle-3 (SLV-3) was India’s first experimental satellite launch vehicle, which was a solid, four stage vehicle weighing 17 tonnes with a height of 22m and capable of placing 40 kg class payloads in Low Earth Orbit (LEO).

SLV-3 was successfully launched on July 18, 1980 from Sriharikota Range (SHAR), when Rohini satellite, RS-1, was placed in orbit, thereby making India the sixth member of an exclusive club of space-faring nations. SLV-3 employed an open loop guidance (with stored pitch programme) to steer the vehicle in flight along a pre-determined trajectory.

The successful culmination of the SLV-3 project paved the way for advancements in launch vehicle projects of ISRO such as the Augmented Satellite Launch Vehicle (ASLV), Polar Satellite Launch Vehicle (PSLV) and the Geosynchronous satellite Launch Vehicle (GSLV).

Augmented Satellite Launch Vehicle


First successful launch: 1987

Current Status: Decommissioned

The Augmented Satellite Launch Vehicle (ASLV) has a lift off weight of 40 tonnes, with a height of 24 m. ASLV is configured in a five stage manner and is an all-solid propellant vehicle, with a mission of orbiting 150 kg class satellites into 400 km circular orbits.

While building upon the experience gained from the SLV-3 missions, ASLV proved to be a low cost intermediate mechanism to demonstrate and validate critical technologies, which would be needed for the future launching missions like strap-on technology, inertial navigation, bulbous heat shield, vertical integration and closed loop guidance.

Under the ASLV programme four developmental flights were conducted. The first developmental flight took place on March 24, 1987 and the second on July 13, 1988.

The third developmental flight, ASLV-D3 was successfully launched on May 20, 1992, when SROSS-C (106 kg) was put into an orbit of 255 x 430 km. ASLV-D4, launched on May 4, 1994, orbited SROSS-C2 weighing 106 kg.

It had two payloads, Gamma Ray Burst (GRB) Experiment and Retarding Potentio Analyser (RPA) and functioned for seven years.

Polar Satellite Launch Vehicle


First successful launch: 1994

Current status: Active

The Polar Satellite Launch Vehicle (PSLV) is the third generation launch vehicle of India. It is the first Indian launch vehicle to be equipped with liquid stages.

After its first successful launch in October 1994, PSLV was regarded as a reliable and versatile workhorse launch vehicle with 39 consecutively successful missions by June 2017.

During 1994-2017, this vehicle had launched 48 Indian satellites and 209 satellites for customers from abroad. Besides, the vehicle successfully launched two spacecraft – Chandrayaan-1 in 2008 and Mars Orbiter Spacecraft in 2013 – that later traveled to Moon and Mars respectively.

The vehicle specifications include a height of 44 m, diameter 2.8 m and four stages. The lift off mass is 320 tonnes(XL). It has 3 variants – PSLV-G, PSLV – CA, PSLV – XL. 

Geosynchronous Satellite Launch Vehicle


First successful launch: 2003

Current status: Active

Geosynchronous Satellite Launch Vehicle Mark II (GSLV Mk II) is the largest launch vehicle developed by India, which is currently in operation.

This fourth generation launch vehicle is a three stage vehicle with four liquid strap-ons. The indigenously developed Cryogenic Upper Stage (CUS), which is flight proven, forms the third stage of GSLV Mk II.

From January 2014, the vehicle has achieved four consecutive successes. It has a height of 49.13 m, three stages and a lift off mass of 414.75 tonnes.

Geosynchronous Satellite Launch Vehicle Mark III


First successful launch: 2014

Current status: Active

GSLV MkIII, chosen to launch Chandrayaan-2 spacecraft, is a three-stage heavy lift launch vehicle developed by ISRO. The vehicle has two solid strap-ons, a core liquid booster and a cryogenic upper stage.

GSLV Mk III is designed to carry 4 ton class of satellites into Geosynchronous Transfer Orbit (GTO) or about 10 tons to Low Earth Orbit (LEO), which is about twice the capability of the GSLV Mk II.

The two strap-on motors of GSLV Mk III are located on either sides of its core liquid booster. Designated as ‘S200’, each carries 205 tons of composite solid propellant and their ignition results in vehicle lift-off. S200s function for 140 seconds.

During strap-ons functioning phase, the two clustered Vikas liquid Engines of L110 liquid core booster will ignite 114 sec after lift -off to further augment the thrust of the vehicle. These two engines continue to function after the separation of the strap-ons at about 140 seconds after lift -off.

The first experimental flight of LVM3, the LVM3-X/CARE mission lifted off from Sriharikota on December 18, 2014 and successfully tested the atmospheric phase of flight. Crew module Atmospheric Reentry Experiment was also carried out in this flight.

It has a height of 43.43 m, a vehicle diameter of 4 m, a heat shield diameter of 5 m and a lift off mass of 640 tonnes. 

Reusable Launch Vehicle – Technology Demonstrator


Reusable Launch Vehicle – Technology Demonstrator (RLV-TD) is one of the most technologically challenging endeavors of ISRO towards developing essential technologies for a fully reusable launch vehicle to enable low cost access to space.

The configuration of RLV-TD is similar to that of an aircraft and combines the complexity of both launch vehicles and aircraft.

The winged RLV-TD has been configured to act as a flying test bed to evaluate various technologies, namely, hypersonic flight, autonomous landing and powered cruise flight. In future, this vehicle will be scaled up to become the first stage of India’s reusable two stage orbital launch vehicle.


RLV-TD consists of a fuselage (body), a nose cap, double delta wings and twin vertical tails. It also features symmetrically placed active control surfaces called Elevons and Rudder.

This technology demonstrator was boosted to Mach no: 5 by a conventional solid booster (HS9) designed for low burn rate.  The selection of materials like special alloys, composites and insulation materials for developing an RLV-TD and the crafting of its parts is very complex and demands highly skilled manpower.

Many high technology machinery and test equipment were utilized for building this vehicle.

Objectives of ISRO’s RLV-TD:

  • Hypersonic aero thermodynamic characterization of wing body.
  • Evaluation of autonomous Navigation, Guidance and Control (NGC) schemes.
  • Integrated flight management.
  • Thermal Protection System Evaluation.

Scramjet Engine TD

ISRO Scramjet Engine

The first experimental mission of ISRO’s Scramjet Engine towards the realization of an Air Breathing Propulsion System was successfully conducted on August 28, 2016 from Satish Dhawan Space Centre SHAR, Sriharikota.

After a flight of about 300 seconds, the vehicle touched down in the Bay of Bengal, approximately 320 km from Sriharikota. The vehicle was successfully tracked during its flight from the ground stations at Sriharikota.

With this flight, critical parameters such as ignition of air breathing engines at supersonic speed, holding the flame at supersonic speed, air intake mechanism and fuel injection systems have been successfully demonstrated.

The Scramjet engine designed by ISRO uses Hydrogen as fuel and the Oxygen from the atmospheric air as the oxidizer. This test was the maiden short duration experimental test of ISRO’s Scramjet engine with a hypersonic flight at Mach 6.

ISRO’s Advanced Technology Vehicle (ATV), which is an advanced sounding rocket, was the solid rocket booster used for the test of Scramjet engines at supersonic conditions.  ATV carrying Scramjet engines weighed 3277 kg at lift-off.

Future Rockets


The Unified Launch Vehicle (ULV) is a development project by the Indian Space Research Organisation (ISRO) whose sole objective is to design a modular architecture which would eventually replace the PSLVGSLV Mk I/II and GSLV Mk III with a single family of launchers.

The design may include a heavy-lift variant dubbed HLV, consisting of the SC-160 stage and two solid rocket boosters, as well as a super heavy-lift variant called SHLV with a cluster stage of five SCE-200 engines.

As SCE-200 will only fly after the successful completion of the Gaganyaan program, the launcher will not fly before 2022. The range of masses are- 270,000 to 700,000 kg. As of May 2013, based on ISRO data, the design comprised a common core and upper stage, with four different booster sizes. 


All four versions of the boosters are solid motors, with at least three versions reusing current motors from the PSLV, GSLV Mk I/II and LVM3. The core, known as the SC160 (Semi-Cryogenic stage with 160 tonnes of propellant, in the ISRO nomenclature), would have 160,000 kg (350,000 lb) of Kerosene / LOX propellant and be powered by a single SCE-200 rocket engine. The upper stage, known as the C30 (Cryogenic stage with 30 tonnes of propellant) would have 30,000 kg (66,000 lb) of LH2 / LOX propellant and be powered by a single CE-20 engine. 

The four booster options are:-

  • 6 × S-13, slightly larger than the S-12 on PSLV, to burn longer;
  • 2 × S-60, which appears to be a new solid motor development;
  • 2 × S-139, which is the first stage of PSLV and GSLV Mk I/II;
  • 2 × S-200, like on the LVM3.

Heavy Lift Launch Vehicle (HLV-Variant):-

A potential heavy-lift variant (HLV) of the unified launcher capable of placing up to 10 ton class of spacecrafts into Geosynchronous Transfer Orbit would include:- 

  • A larger dual S-250 solid strap-on boosters as compared to the S-200 boosters used in LVM3;
  • A L-400 semi-cryogenic core stage, with 400 tonnes of propellant, using a cluster of five SCE-200 engine’s;
  • A L-27 cryogenic third stage, with 27 tonnes of propellant, using CE-20 engine.

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