Launch Vehicles are used to transport and put satellites or spacecrafts into space. In India, the launch vehicles development programme began in the early 1970s. The first experimental Satellite Launch Vehicle (SLV-3) was developed in 1980. An Augmented version of this, ASLV, was launched successfully in 1992. India has made tremendous strides in launch vehicle technology to achieve self-reliance in satellite launch vehicle programme with the operationalisation of Polar Satellite Launch Vehicle (PSLV) and Geosynchronous Satellite Launch Vehicle (GSLV).
A. First Generation Launchers: These launchers are divided in two categories:
(i) Sounding rockets (ii) Operational sounding rockets
i. Sounding Rockets: Sounding rockets are usually one or two stage solid propellant rockets. They are primarily intended for probing the upper atmospheric regions using rocket-borne instrumentation. They also serve as platforms for testing prototypes of new components or subsystems intended for use in launch vehicles and satellites. The launch of the first sounding rocket US made ‘Nike Apache’ from Thumba near Thiruvananthapuram, Kerala on November 21, 1963, marked the beginning of the Indian Space Programme.
In 1965, ISRO started launching a series of our own sounding rockets named Rohini from TERLS. RH-75, with a diameter of 75mm was the first truly Indian sounding rocket, which was followed by RH-100 and RH-125 rockets. The sounding rocket programme was indeed the bedrock on which the edifice of launch vehicle technology was built. The experience gained was of immense value in the mastering of solid propellant technology and allied systems of the launch vehicles. Several scientific missions with national and international participation have been conducted using the Rohini sounding rockets.
ii. Operational Sounding Rockets: Currently, operational sounding rockets include three versions namely RH-200, RH-300-Mk-II and RH-560-Mk-III. These cover a payload range of 8 to 100 kg and an apogee range of 80 to 475 km. The details are as given below.
|Payload (in kg)||10.5||70||100|
|Altitude (in km)||75||120||550|
|Purpose||Meterology||Middle atmospheric studies||Upper atmospheric studies|
Operational sounding rockets are further divided in two groups:
(a) Satellite Launch Vehicle (SLV)
(b) Augmented Satellite Launch Vehicle (ASLV)
a. The Satellite Launch Vehicle (SLV):The Satellite Launch Vehicle (SLV) project was born out of the need for achieving indigenous satellite launch capability for communications, remote sensing and meteorology. SLV3, India's first experimental launch vehicle, was capable of placing 40 kg class payloads in Low Earth Orbit (LEO). It was an all solid, four stages, 22m tall vehicle, and weighing 17 ton.
The first experimental flight of SLV3, in August 1979, was only partially successful. The next launch on July 18, 1980 from Sriharikota Range (SHAR), successfully placed Rohini satellite, RS-1, into the orbit, thereby making India the sixth member of an exclusive club of space-faring
The successful culmination of the SLV3 project paved the way to advanced launch vehicle projects such as the Augmented Satellite Launch Vehicle (ASLV), Polar Satellite Launch Vehicle (PSLV) and the Geosynchronous satellite Launch Vehicle (GSLV).
b. The Augmented Satellite Launch Vehicle (ASLV): Augmented Satellite Launch Vehicle (ASLV) was developed to act as a low cost intermediate vehicle to demonstrate and validate critical technologies. With a lift off weight of 40 tonnes, the 23.8 m tall ASLV was configured as a five stage, all-solid propellant vehicle, with a mission of orbiting 150 kg class satellites into 400 km circular orbits. The strap-on stage consisted of two identical 1m diameter solid propellant motors, 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. 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. ASLV provided valuable inputs for further development.
B. Operational Launchers:
Operational Launchers are further divided in two groups:
(i) Satellite Launch Vehicle (SLV)
(ii) Augmented Satellite Launch Vehicle (ASLV)
i. Polar Satellite Launch Vehicle: The Polar Satellite Launch Vehicle, usually known by its abbreviation PSLV is the first operational launch vehicle of ISRO. PSLV is capable of launching 1600 kg satellites in 620 km sun-synchronous polar orbit and 1050 kg satellite in geo-synchronous transfer orbit. In the standard configuration, it measures 44.4 m tall, with a lift off weight of 295 tonnes. PSLV has four stages using solid and liquid propulsion systems alternately. The first stage is one of the largest solid propellant boosters in the world and carries 139 tonnes of propellant. A cluster of six strap-ons attached to the first stage motor, four of which are ignited on the ground and two are air-lit.
The reliability rate of PSLV has been superb. With its variant configurations, PSLV has proved its multi-payload, multi-mission capability in a single launch and its geosynchronous launch capability. In the Chandrayaan-mission, another variant of PSLV with an extended version of strap-on motors, PSOM-XL, the payload haul was enhanced to 1750 kg in 620 km SSPO. PSLV has rightfully earned the status of workhorse launch vehicle of ISRO.
Vehicle Variants and Launch Capability
• No. of Solid Strap-ons : Six (9T)
• Payload capability to SSPO (600 km) : 1550 kg
• No. of Solid Strap-ons : NIL
• Payload capability to SSPO (600 km) : 1100 Kg
• No. of Solid Strap-ons : Six (12T)
• Payload capability o SSPO (600 Km) : 1700 kg
• Payload capability o sub GTO (284 x 20650 km) 1425 Kg
• PSLV-C29 / TeLEOS-1 mission in March 2016
• PSLV-C32 / IRNSS-1G mission in June 2016
• PSLV-C33 / CARTO-2C mission in September 2016
• PSLV-C35 / RESOURCESAT-2A mission in December 2016
ii. Geosynchronous Satellite Launch Vehicle (GSLV): Geosynchronous Satellite Launch Vehicle (GSLV) is capable of placing 2 ton class of satellites like the INSAT and GSAT series of communication satellites into Geosynchronous Transfer Orbit (GTO). GSLV is a 49 m tall, three stage vehicle with a lift-off mass of 416 ton. The first stage comprises of a S139 solid booster with four liquid strap-on motors, each weighing 40 ton. The second stage (GS2) is a liquid engine carrying 37.5 ton of liquid propellant. The third stage is the indigenously built Cryogenic Upper Stage (CUS) which uses typically 15 ton of cryogenic propellants (Liquid Hydrogen (LH2) as fuel and Liquid Oxygen (LOX) as Oxidiser).
C. Next Generation Launchers: The Geosynchronous Satellite Launch Vehicle Mark III (GSLV MkIII) also known as LVM3, is the next generation launcher being developed by ISRO for achieving self reliance in the launch of 4 ton class of communication satellites to Geosynchronous Transfer Orbits (GTO). The launcher is designed to be a versatile launcher to launch payloads to other orbits as well and will have a payload capability in excess of 10 ton to Low Earth Orbits (LEO). Once GSLV-MkIII becomes operational, India would be able to dispense the procured launches for 4 ton class communication satellites.
Upcoming Launches: LVM3 developmental flight with a fully functional cryogenic stage is targeted in 2016-17.
Image source: www.isro.gov.in