2. Introduction to ISRO (Indian
Space Research Organisation)
ISRO STANDS FOR INDIAN SPACE RESEARCH ORGANISATION, WHICH IS
THE NATIONAL SPACE AGENCY OF INDIA. IT WAS FOUNDED IN 1969 AND
HAS ITS HEADQUARTERS IN BENGALURU. ITS VISION IS TO “HARNESS
SPACE TECHNOLOGY FOR NATIONAL DEVELOPMENT WHILE PURSUING
SPACE SCIENCE RESEARCH AND PLANETARY EXPLORATION”.
3. OVERVIEW
The Indian Space Research Organisation, commonly referred to
as ISRO, is the national space agency of India. It operates
under the Department Of Space (DOS) which is directly
overseen by the Prime Minister of India, while the Chairman of
ISRO also acts as the executive of DOS. The organisation is
involved in science, engineering and technology to harvest the
benefits of outer space for India and the mankind. ISRO is a
major constituent of the Department of Space (DOS),
Government of India.ISRO was previously The Indian National
Committee for Space Research (INCOSPAR), set up by The
Government of India in 1962, as envisioned by scientist Vikram
Sarabhai, recognising the need in space research. INCOSPAR
grew and became ISRO in 1969.
4. History Of ISRO
Modern space research in India can be traced to the 1920s, when scientist S. K. Mitra conducted a series of experiments sounding of
the ionosphere through ground-based radio in Kolkata.
The Indian National Committee for Space Research (INCOSPAR) was set up in 1962 by Prime Minister Jawaharlal Nehru on the suggestion of
Dr. Vikram Sarabhai. Initially there was no dedicated ministry for the space programme and all activities of INCOSPAR.
Under the government of Indira Gandhi, INCOSPAR was superseded by ISRO. Later in 1972, a space commission and Department of Space
(DOS) were set up to oversee space technology development in India specifically and ISRO was brought under DOS, institutionalising space
research in India and forging the Indian space program into its existing form.
India joined the Soviet Interkosmos program for space cooperation and got its first satellite Aryabhatta in orbit through a Soviet rocket.
It took 7 years for ISRO to develop Satellite Launch Vehicle capable of putting 40 kg (88 lb) into a 400-kilometre (250 mi) orbit. An SLV Launch
Pad, ground stations, tracking networks, radars and other communications were set up for a launch campaign. The SLV's first launch in 1979
carried a Rohini technology payload but could not inject the satellite into its desired orbit. It was followed by a successful launch in 1980
carrying a Rohini Series-I satellite, making India the seventh country to reach Earth's orbit after the USSR, the US, France, the UK, China and
Japan.
In 2003, when China sent humans into space, Prime Minister Atal Bihari Vajpayee urged scientists to develop technologies to land humans on
the Moon and programmes for lunar, planetary and crewed missions were started. ISRO launched Chandrayaan-1 in 2008, purportedly the first
probe to verify the presence of water on the Moon and the Mars Orbiter Mission in 2013, the first Asian spacecraft to enter Martian orbit; India
was the first country to succeed at that on its first attempt.
5. Satellite Launch Vehicles
(SLVS)
The Satellite Launch Vehicle (known as SLV-3) was the first space rocket to be
developed by India. The initial launch in 1979 was a failure followed by a successful
launch in 1980 making India the sixth country in world with orbital launch capability.
The development of bigger rockets began afterwards.
Development of SLVS
The Satellite Launch Vehicle or SLV was a small-lift launch vehicle project started in
the early 1970s by the Indian Space Research Organisation to develop the
technology needed to launch satellites. SLV was intended to reach a height of 400
kilometres and carry a payload of 40 kg.
The first experimental flight of SLV, in August 1979, was a failure whereas The first
successful launch took place on 18 July 1980.
It was a four-stage rocket with all solid-propellant motors..
The first launch of the SLV took place in Sriharikota on 10 August 1979. The fourth and
final launch of the SLV took place on 17 April 1983
All four SLV launches occurred from the SLV Launch Pad at the Sriharikota High Altitude
Range. The first two launches were experimental (E) and the next 2 were designated as
developmental (D) as this was the first launch vehicle being developed by India not
intended for a long service life.
6. Different SLVs Used By
ISRO
1. Polar Satellite Launch Vehicle (PSLV) ---->
2. Geosynchronous Satellite Launch Vehicle
(GSLV) ---->
3. Geosynchronous Satellite Launch Vehicle Mark
III (GSLV MK3)--->
7. Polar Satellite Launch Vehicle (PSLV)
Polar Satellite Launch Vehicle or PSLV is the first medium-lift launch vehicle from India which enabled
India to launch all its remote-sensing satellites into Sun-synchronous orbit.
Features and Capabilities
The first stage, one of the largest solid rocket boosters in the world, carries 138 t of hydroxyl-terminated
polybutadiene-bound (HTPB) propellant and develops a maximum thrust of about 4,800 kN .
The second stage is powered by a single Vikas engine and carries 41.5 t (40.8 long tons; 45.7 short tons) of Earth store-able liquid
propellant – unsymmetrical dimethylhydrazine (UDMH) as fuel and nitrogen tetroxide as oxidiser in two tanks separated by a common
bulkhead.
The third stage uses 7.6 of HTPB solid propellant and produces a maximum thrust of 250 kN . Its burn duration is 113.5 seconds. It has a Kevlar-polyamide fibre case and
a submerged nozzle
PS4 has carried hosted payloads like AAM on PSLV-C8, Rubin 9.1/Rubin 9.2 on PSLV-C14 and mRESINS on PSLV-C21. But now, PS4 is
being augmented to serve as a long duration orbital platform after completion of primary mission.
Payload fairing of PSLV, also referred as its "Heatshield" consists of a conical upper section with spherical nose-cap, a cylindrical middle
section and a lower boat-tail section. Weighing 1,182 kilograms , it has 3.2 meter diameter and 8.3 meter height. It
has Isogrid construction and is made out of 7075 aluminum alloy with a 3 mm thick steel nose-cap.
PSLV's successful missions and Satellite launches
Some notable payloads launched by PSLV include India's first lunar probe Chandrayaan-1, India's first interplanetary mission, Mars
Orbiter Mission (Mangalyaan) and India's first space observatory, Astrosat.
As of July 30, 2023 the PSLV has made 58 launches, with 55 successfully reaching their planned orbits, two outright failures and one
partial failure, yielding a success rate of 94% . All launches have occurred from the Satish Dhawan Space Centre, known before 2002 as
the Sriharikota Range (SHAR).
8. Geosynchronous Satellite
Launch Vehicle
(GSLV)
Geosynchronous Satellite Launch Vehicle was envisaged in 1990s to
transfer significant payloads to geostationary orbit. ISRO initially had a
great problem realising GSLV as the development of CE-7.5 in India took a
decade. The US had blocked India from obtaining cryogenic technology
from Russia, leading India to develop its own cryogenic engines.
Features and Capabilities of GSLV
The first GSLV flight, GSLV-D1 used the L40 stage. Subsequent flights of
the GSLV used high pressure engines in the strap-on boosters called the
L40H. The GSLV uses four L40H liquid strap-on boosters derived from the
L37.5 second stage, which are loaded with 42.6 tons
of hypergolic propellants.
GSLV-D1 used the S125 stage which contained 125 t of solid propellant
and had a burn time of 100 seconds. All subsequent launches have used
enhanced propellant loaded S139 stage.
The GS2 stage is powered by the Vikas engine. It has a diameter of 2.8 m.
The third stage of the GSLV Mark II is propelled by the Indian CE-
7.5 cryogenic rocket engine while the older defunct Mark I is propelled
using a Russian made KVD-1. It uses liquid hydrogen and liquid oxygen.
The Indian cryogenic engine was built at the Liquid Propulsion Systems
Centre
GSLV's achievements and Important Missions
As of May 29, 2023, rockets from the GSLV family have made 15 launches,
resulting in 9 successes, four failures, and two partial failures. All launches
have occurred from the Satish Dhawan Space Centre, known before 2002
as the Sriharikota Range (SHAR).
GSLV MK.I Flight D1 was the first developmental flight of
the GSLV Mk.I featuring Russian cryogenic engine KVD-1. It was used
to place an experimental satellite GSAT-1 into the orbit. However, due
to sub-optimal performance and lack of fuel the vehicle did not
achieve the intended orbit and the satellite had to maneuver itself
using onboard fuel to correct the shortfall.
GSLV MK.II Flight D2 was the second test flight with indigenous
cryogenic stage CE-7.5 and the first successful launch with the CE-7.5
GSLV MK.II Flight F09 was the fourth consecutive successful flight of
GSLV Mk. II with indigenous cryogenic engine. The flight placed the
regional satellite South Asia Satellite was previously named as South
Asian Association for Regional Cooperation (SAARC) Satellite.
9. Geosynchronous Satellite Launch Vehicle Mark
III
(GSLV Mk III)
Launch Vehicle Mark-3 (LVM3), previously known as GSLV Mk III, is the heaviest rocket in operational service with ISRO. Equipped with
a more powerful cryogenic engine and boosters than GSLV, it has significantly higher payload capacity and allows India to launch all its
communication satellites.
Features and Capabilities of GSLV Mk III
The first stage consists of two S200 solid motors, also known as Large Solid Boosters (LSB) attached to the core stage.
Each booster is 3.2 metres wide, 25 metres long, and carries 207 tonnes of hydroxyl-terminated polybutadiene (HTPB)
based propellant in three segments with casings made out of M250 maraging steel. It is the largest solid-fuel booster
after the SLS SRBs, the Space Shuttle SRBs and the Ariane 5 SRBs.
The second stage, designated L110, is a liquid-fueled stage that is 21 metres tall and 4 metres wide, and contains 110
metric tons of unsymmetrical dimethylhydrazine (UDMH) and nitrogen tetroxide. It is powered by two Vikas 2 engines.
The cryogenic upper stage, designated C25, is 4 metres in diameter and 13.5 metres long, and contains 28 metric
tons of propellant LOX and LH2, pressurized by helium stored in submerged bottles. It is powered by a single CE-
20 engine.
Role of GSLV Mk III in India's Human Space Flight Program
The Indian Human Spaceflight Programme is an ongoing programme by the Indian Space Research
Organisation (ISRO) to develop the technology needed to launch crewed orbital spacecraft into low Earth orbit.Two
uncrewed flights, named Gaganyaan-1 and Gaganyaan-2 are scheduled to launch in 2024 followed by crewed flight in
2025 on an LVM3 rocket.
ISRO plans to launch its crewed orbiter Gaganyaan atop a Geosynchronous Satellite Launch Vehicle Mk III (GSLV Mk
III).About 16 minutes after lift-off, the rocket will inject the orbital vehicle into an orbit 300 to 400 km above Earth. The
capsule would return for a splashdown in the Arabian Sea near the Gujarat coastline. As of May 2019, design of crew
module has been completed.
