View source for Geosynchronous Satellite Launch Vehicle

{{Short description|Class of Indian medium-lift expendable launch vehicles, developed by ISRO}}
{{Use Indian English|date=March 2021}}
{{Use dmy dates|date=March 2021}}
{{Infobox Rocket
| name           = GSLV
| image          = {{CSS image crop |Image =  
GSLV-F14, INSAT-3DS - Launch Vehicle at Second Launch Pad (SLP).webp|bSize= 850 |cWidth =250 |cHeight = 480 |oTop =40 |oLeft =290|Location=center}}
| caption        = GSLV-F14 carrying INSAT-3DS at the [[Satish Dhawan Space Centre Second Launch Pad]]
| upright        = 1.2
| function       = [[Medium-lift launch vehicle|Medium-lift Launch System]]
| manufacturer   = ISRO
| country-origin = India
| cpl            = US$47 million<ref>{{cite web|title=GAO|url=http://www.gao.gov/products/GAO-17-609}}</ref>
| height         = {{cvt|49.13|m}}<ref name="gslv">{{cite web|url=http://isro.gov.in/launchers/gslv|title=Geosynchronous Satellite Launch Vehicle|access-date=21 December 2014|archive-url=https://web.archive.org/web/20151021032054/http://www.isro.gov.in/launchers/gslv|archive-date=21 October 2015|url-status=dead}}</ref>
| diameter       = {{cvt|2.8|m}}
| mass           = {{cvt|414750|kg}}
| stages         = 3

| capacities = {{Infobox rocket/Payload
| location       = [[Low Earth orbit|LEO]]
| kilos          = {{cvt|6000|kg}}<ref name="GSLV_SSO">{{cite web |title=HSFC Presentation from International Space Conference and Exhibition 2021 |url=https://ciihive.in/Attachments/Exhibitor/35711_HSFCStandeefinal.pdf |access-date=7 October 2022 |archive-url=https://web.archive.org/web/20210913121945/https://ciihive.in/Attachments/Exhibitor/35711_HSFCStandeefinal.pdf |archive-date=13 September 2021}}</ref>
}}
{{Infobox rocket/Payload
| location       = [[Sun-synchronous orbit|SSO]]
| kilos          = {{cvt|3000|kg}}<ref name="GSLV_SSO" />
}}
{{Infobox rocket/Payload
| location       = [[Geosynchronous transfer orbit|GTO]]
| kilos          = {{cvt|2500|kg}}<ref name="gslv"/><ref name="FL20180829">{{cite news|title=ISRO developing vehicle to launch small satellites|url=https://frontline.thehindu.com/science-and-technology/article24801393.ece|access-date=29 August 2018}}</ref>
}}
| status = {{plainlist|
* '''Mk I:''' Retired
* '''Mk II:''' Active
}}
| sites          = [[Satish Dhawan Space Centre]]
| launches       = [[List of GSLV launches#Launch history|17]] + 7 (planned)
| success        = 11
| fail           = 4
| partial        = 2
| first          = {{plainlist|
* '''Mk.I:''' 18 April 2001
* '''Mk.II:''' 15 April 2010
}}
| payloads       = * [[INSAT]]
* [[GSAT]] ([[South Asia Satellite]])
* [[GISAT]]
* [[IRNSS|NVS]]
* [[NISAR]] 
| last           = {{plainlist|
* '''Mk.I:''' 25 December 2010
* '''Mk.II:''' 29 January 2025
}}

| stagedata = {{Infobox rocket/Stage
| type           = booster
| number         = 4 L40 Hs
| length         = {{cvt|19.7|m}}<ref name=F09borchure>{{cite web|url=http://www.isro.gov.in/gslv-f09-gsat-9/gslv-f09-brochure|title=GSLV F09 Brochure|publisher=ISRO}}</ref>
| diameter       = {{cvt|2.1|m}}
| engines        = 1 [[L40H Vikas]] 2
| thrust         = {{cvt|760|kN}}<ref name=F08borchure>{{cite web|url=https://www.isro.gov.in/gslv-f08-gsat-6a-mission/gslv-f08-gsat6a-brochure|title=GSLV F08 Brochure|publisher=ISRO|access-date=26 March 2018|archive-date=10 July 2021|archive-url=https://web.archive.org/web/20210710162623/https://www.isro.gov.in/gslv-f08-gsat-6a-mission/gslv-f08-gsat6a-brochure|url-status=dead}}</ref>
| total          = {{cvt|3040|kN}}
| SI             = {{cvt|262|isp}}
| burntime       = 154 seconds
| fuel           = [[Dinitrogen tetroxide|N<sub>2</sub>O<sub>4</sub>]] / [[Unsymmetrical dimethylhydrazine|UDMH]]
| empty          = 
| gross          = 
| propmass       = {{cvt|42700|kg}} each
}}

{{Infobox rocket/Stage
| type           = stage
| stageno        = First<ref name=F08borchure/><ref name=F09borchure/>
| length         = {{cvt|20.2|m}}
| diameter       = {{cvt|2.8|m}}
| engines        = 1 [[S139 Booster]]
| thrust         = {{cvt|4846.9|kN}}
| SI             = {{cvt|237|isp}}
| burntime       = 100 seconds
| fuel           = [[HTPB]] ([[Solid rocket|solid]])
| propmass       = {{cvt|138200|kg}}
}}

{{Infobox rocket/Stage
| type           = stage
| stageno        = Second<ref name=F08borchure/><ref name=F09borchure/>
| length         = {{cvt|11.6|m}}
| diameter       = {{cvt|2.8|m}}
| engines        = 1 [[GS2 Vikas]] 4
| thrust         = {{cvt|846.8|kN}}
| SI             = {{cvt|295|isp}}
| burntime       = 139 seconds
| fuel           = N<sub>2</sub>O<sub>4</sub> / UDMH
| propmass       = {{cvt|39500|kg}}
}}

{{Infobox rocket/Stage
| type           = stage
| stageno        = Second GS2 (GL40)<ref name=F08borchure/><ref name=F11borchure>{{cite web|url=https://www.isro.gov.in/gsat-f11-gsat-7a-mission/gslv-f11-gsat-7a-brochure|title=GSLV F11 Brochure|publisher=ISRO}}</ref>
| length         = {{cvt|11.9|m}}
| diameter       = {{cvt|2.8|m}}
| engines        = 1 [[GS2 Vikas]] 4
| thrust         = {{cvt|846.8|kN}}
| SI             = {{cvt|295|isp}}
| burntime       = 149 seconds
 |fuel           = N<sub>2</sub>O<sub>4</sub> / UDMH
| propmass       = {{cvt|42500|kg}}
}}

{{Infobox rocket/Stage
| type           = stage
| diff           = GSLV Mk I
| stageno        = Third<ref name=F09borchure/>
| length         = [[N/A]]
| diameter       = {{cvt|2.8|m}}
| name           = CUS
| engines        = 1 [[KVD-1]]
| thrust         = {{cvt|70|kN}}
| SI             = {{cvt|462|isp}} 
| burntime       = [[N/A]]
| fuel           = [[Liquid oxygen|LOX]] / [[Liquid hydrogen|LH<sub>2</sub>]]
| propmass       = [[N/A]]
}}

{{Infobox rocket/Stage
| type           = stage
| diff           = GSLV Mk II
| stageno        = Third<ref name=F09borchure/>
| length         = {{cvt|8.7|m}}
| diameter       = {{cvt|2.8|m}}
| name           = CUS12
| engines        = 1 [[CE-7.5]]
| thrust         = {{cvt|75|kN}}
| SI             = {{cvt|454|isp}}
| burntime       = 718 seconds
| fuel           = [[Liquid oxygen|LOX]] / [[Liquid hydrogen|LH<sub>2</sub>]]
| propmass       = {{cvt|12800|kg}}
}}

{{Infobox rocket/Stage
| type           = stage
| diff           = GSLV Mk II
| stageno        = Third<ref name=F11borchure/>
| length         = {{cvt|9.9|m}}
| diameter       = {{cvt|2.8|m}}
| name           = CUS15
| engines        = 1 [[CE-7.5]]
| thrust         = {{cvt|75|kN}}
| SI             = {{cvt|454|isp}}
| burntime       = 846 seconds
| fuel           = [[Liquid oxygen|LOX]] / [[Liquid hydrogen|LH<sub>2</sub>]]
| propmass       = {{cvt|15000|kg}}
}}
|logo=[[File:GSLV logo.svg|100px|GSLV_logo]]}}

'''Geosynchronous Satellite Launch Vehicle''' ('''GSLV''') is a class of [[expendable launch systems]] operated by the [[ISRO|Indian Space Research Organisation]] (ISRO). GSLV has been used in [[List of GSLV launches|fifteen launches]] since 2001.

== History ==
The Geosynchronous Satellite Launch Vehicle (GSLV) project was initiated in 1990 with the objective of acquiring an Indian launch capability for [[geosynchronous satellite]]s.<ref>{{cite journal|title=GSLV Launched Successfully|journal=Current Science|date=May 2001|volume=80|issue=10|page=1256|url=http://www.iisc.ernet.in/currsci/may252001/1254.pdf|access-date=12 December 2013}}</ref><ref name=flGSLVQuest>{{cite news|last=Subramanian|first=T. S.|title=The GSLV Quest|url=http://www.frontline.in/navigation/?type=static&page=flonnet&rdurl=fl1806/18060820.htm|access-date=12 December 2013|newspaper=Frontline|date=March 17–31, 2001}}</ref>

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-propellant rocket|liquid-fueled]] [[Vikas (rocket engine)|Vikas engine]]. Due to the thrust required for injecting the satellite in a [[geostationary transfer orbit]] (GTO) the third stage was to be powered by a [[LOX]]/[[LH2|LH<sub>2</sub>]] Cryogenic engine which at that time India did not possess or have the technological expertise to build. The aerodynamic characterization research was conducted at the [[National Aerospace Laboratories]]' 1.2m Trisonic Wind Tunnel Facility.<ref>{{Cite web |date=2022-06-06 |title=Bengaluru: 1.2m trisonic wind tunnel at National Aerospace Laboratories completes 55 years of service |url=https://www.aninews.in/news/national/general-news/bengaluru-12m-trisonic-wind-tunnel-at-national-aerospace-laboratories-completes-55-years-of-service20220606001500/ |access-date=2024-11-22 |website=ANI |language=en}}</ref>
[[File:GS2 stage for GSLVF16.jpg|Second stage of GSLV (GS2) for the [[GSLV F16]] flight|thumb|left]]
[[File:GSLV-F14, INSAT-3DS - Third stage GS3 being transported to VAB.jpg|thumb|upright=1.0|left|Indigenous Cryogenic Upper Stage [[CE-7.5]] of GSLV]]

The first development flight of the GSLV (Mk I configuration) was launched on 18 April 2001 was a failure as the payload failed to reach the intended orbit parameters. The launcher was declared operational after the second development flight successfully launched the [[GSAT-2]] satellite. During the initial years from the initial launch to 2014 the launcher had a checkered history with only 2 successful launches out of 7, resulting in the rocket gaining the nickname "naughty boy".<ref name="Naughty">{{cite web|title=GSLV Rocket, Billed 'Naughty Boy'|url=https://www.ndtv.com/india-news/gslv-rocket-billed-naughty-boy-by-scientists-is-now-adorable-1456610|website=NDTV|access-date=11 February 2018|archive-url=https://web.archive.org/web/20180211150611/https://www.ndtv.com/india-news/gslv-rocket-billed-naughty-boy-by-scientists-is-now-adorable-1456610|archive-date=11 February 2018}}</ref><ref>{{cite web|author1=Jacob Aron|title=India's hefty "naughty boy" rocket comes in from cold|url=https://www.newscientist.com/article/dn24821-indias-hefty-naughty-boy-rocket-comes-in-from-cold/ |website=New Scientist|access-date=11 February 2018|archive-url=https://web.archive.org/web/20180211151103/https://www.newscientist.com/article/dn24821-indias-hefty-naughty-boy-rocket-comes-in-from-cold/ |archive-date=11 February 2018}}</ref>

=== Cryogenic engine controversy ===
The third stage was to be procured from Russian company [[Glavkosmos]], including transfer of technology and design details of the engine based on an agreement signed in 1991.<ref name=flGSLVQuest/> Russia backed out of the deal after United States objected to the deal as in violation of the [[Missile Technology Control Regime]] (MTCR) in May 1992. As a result, ISRO initiated the '''Cryogenic Upper Stage Project''' in April 1994 and began developing its own cryogenic engine.<ref name=GSLVGopalRaj>{{cite news|last=Raj|first=N Gopal|title=The long road to cryogenic technology
|url=http://www.thehindu.com/opinion/lead/the-long-road-to-cryogenic-technology/article397441.ece|access-date=12 December 2013|newspaper=The Hindu|date=21 April 2011|location=Chennai, India}}</ref> A new agreement was signed with Russia for 7 [[KVD-1]] cryogenic stages and 1 ground mock-up stage with no technology transfer, instead of 5 cryogenic stages along with the technology and design as per the earlier agreement.<ref>{{cite news|last=Subramanian|first=T. S.|title=The cryogenic quest|url=http://www.frontline.in/static/html/fl1809/18090140.htm|access-date=13 December 2013|newspaper=Frontline|date=28 April – 11 May 2001}}</ref> These engines were used for the initial flights and were named GSLV Mk I.<ref>{{cite web|title=Why ISRO's New Engine and Mk III Rocket Are Reasons to Forget 1990 Cryogenic Scandal |url=https://thewire.in/138915/cryogenic-ce-20-isro-gslv-mk-iii/|publisher=The Wire|access-date=10 February 2018}}</ref>

== Vehicle description ==
The {{cvt|49|m}} tall GSLV, with a lift-off mass of {{cvt|415|MT}}, is a three-stage vehicle with solid, liquid and cryogenic stages respectively. The payload fairing, which is {{cvt|7.8|m}} long and {{cvt|3.4|m}} in diameter, protects the vehicle electronics and the spacecraft during its ascent through the atmosphere. It is discarded when the vehicle reaches an altitude of about {{cvt|115|km}}.<ref name=isroGSLVF04>{{cite web|title=GSLV-F04|url=http://www.isro.gov.in/gslv-d5/d5-updates.aspx|publisher=ISRO|access-date=15 December 2013|url-status=dead|archive-url=https://web.archive.org/web/20140104204430/http://isro.gov.in/gslv-d5/d5-updates.aspx|archive-date=4 January 2014}}</ref>{{Needs update|date=August 2021|reason=Needs to include 4m PLF variants flown on F06 and F10 flights}}

GSLV employs [[S band|S-band]] telemetry and [[C band (IEEE)|C-band]] transponders for enabling vehicle performance monitoring, tracking, range safety / flight safety and preliminary orbit determination. The Redundant Strap Down Inertial Navigation System/Inertial Guidance System of GSLV housed in its equipment bay guides the vehicle from lift-off to spacecraft injection. The digital auto-pilot and closed loop guidance scheme ensure the required altitude maneuver and guide injection of the spacecraft to the specified orbit.

The GSLV can place approximately {{cvt|5000|kg}} into an easterly [[low Earth orbit]] (LEO) or {{cvt|2500|kg}} (for the Mk II version) into an 18° [[geostationary transfer orbit]].

[[File:Strap-on motors of GSLV-F05 being integrated with the core stage.jpg|thumb|upright=1.0|left|Strap-on motors of GSLV-F05 being integrated with the core stage]]

=== Liquid boosters ===
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.<ref name=isroGSLVD2>{{cite web|title=GSLV-D2
|url=http://isro.gov.in/gslv-d2/gslv-d2.aspx|publisher=ISRO|access-date=15 December 2013|url-status=dead|archive-url=https://web.archive.org/web/20130809215736/http://isro.gov.in/gslv-d2/gslv-d2.aspx|archive-date=9 August 2013}}</ref> The GSLV uses four L40H [[Liquid rocket booster|liquid strap-on boosters]] derived from the L37.5 second stage, which are loaded with 42.6 tons of [[hypergolic]] propellants ([[Unsymmetrical dimethylhydrazine|UDMH]] and [[Dinitrogen tetroxide|N<sub>2</sub>O<sub>4</sub>]]). The propellants are stored in tandem in two independent tanks {{cvt|2.1|m}} diameter. The engine is [[Pump-fed engine|pump-fed]] and generates {{cvt|760|kN}} of thrust, with a burn time of 150 seconds.

=== First stage ===
GSLV-D1 used the S125 stage which contained {{cvt|125|MT}} of solid propellant and had a burn time of 100 seconds. All subsequent launches have used enhanced propellant loaded S139 stage.<ref name=isroGSLVD2/> The S139 stage is 2.8 m in diameter and has a nominal burn time of 100 seconds.<ref name=GSLVD3>{{cite web|url=https://www.isro.gov.in/launchers/gslv|title=GSLV Launcher|publisher=ISRO|access-date=17 March 2021|archive-date=23 March 2019|archive-url=https://web.archive.org/web/20190323171054/https://www.isro.gov.in/launchers/gslv|url-status=dead}}</ref><ref>{{cite web|url=http://www.currentscience.ac.in/Downloads/article_id_093_12_1697_1714_0.pdf|title=Evolution of Indian launch vehicle technologies|publisher=Current Science|access-date=January 27, 2014}}</ref>

[[File:GSLV-F14, INSAT-3DS - Second stage GS2 being placed over first stage GS1.webp|thumb|upright=1.0|left|Hoisting of the GSLV-F14 second stage during vehicle integration]]

=== Second stage ===
The GS2 stage is powered by the [[Vikas (rocket engine)|Vikas engine]]. It has a diameter of {{cvt|2.8|m}}.<ref name=GSLVD3/>

=== Third stage ===
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 (LH<sub>2</sub>) and liquid oxygen (LOX)<ref>{{cite web|url=http://www.isro.gov.in/gslv-d5/gslv-d5.aspx|title=GSLV-D5|access-date=4 January 2014|url-status=dead|archive-url=https://web.archive.org/web/20141006082545/http://www.isro.gov.in/gslv-d5/gslv-d5.aspx|archive-date=6 October 2014}}</ref> The Indian cryogenic engine was built at the [[Liquid Propulsion Systems Centre]].<ref>{{cite web|url=http://www.spacenews.com/launch/100415isro-cryogenic-engine-fails.html|archive-url=https://archive.today/20120526091518/http://www.spacenews.com/launch/100415isro-cryogenic-engine-fails.html |url-status=dead|archive-date=May 26, 2012|title=ISRO's Cryogenic Stage Fails in Maiden Flight|publisher=SpaceNews|access-date=November 27, 2013}}</ref><ref name=hindu-gslvd3>{{cite news
|url=http://www.hindu.com/2010/01/01/stories/2010010152721100.htm|archive-url=https://web.archive.org/web/20100105175717/http://www.hindu.com/2010/01/01/stories/2010010152721100.htm|url-status=dead|archive-date=5 January 2010|location=Chennai, India|newspaper=The Hindu|title=GSLV, PSLV flights put off|date=1 January 2010}}</ref> The engine has a default thrust of {{cvt|75|kN}} but is capable of a maximum thrust of {{cvt|93.1|kN}}. In GSLV-F14 mission, a new white coloured C15 stage was introduced which has more environmental-friendly manufacturing processes, better insulation properties and the use of lightweight materials.<ref>{{Cite web |title=GSLV-F14/INSAT-3DS Gallery |url=https://www.isro.gov.in/GSLV_F14_INSAT_3DS_gallery.html |access-date=2024-02-08 |website=www.isro.gov.in}}</ref>
[[File:Payload Fairing with GSAT-6A being Integrated.jpg|thumb|upright=1.0|left|Payload fairing with [[GSAT-6A]] being integrated]]

== Variants ==
GSLV rockets using the Russian Cryogenic Stage (CS) are designated as the GSLV Mark I while versions using the indigenous Cryogenic Upper Stage (CUS) are designated the GSLV Mark II.<ref>{{Cite web|date=July 2003|title=Space India, April-June 2003|url=https://www.isro.gov.in/sites/default/files/flipping_book/51-SI-Apr-jun-2003/files/assets/common/downloads/Space%20India%20Apr-Jun%202003.pdf|url-status=live|archive-url=https://web.archive.org/web/20210816025908/https://www.isro.gov.in/sites/default/files/flipping_book/51-SI-Apr-jun-2003/files/assets/common/downloads/Space%20India%20Apr-Jun%202003.pdf|archive-date=16 August 2021|access-date=16 August 2021|page=11}}</ref><ref name=GSLVD3brochure>{{cite web|title=GSLV-D3/GSAT-4 Brochure|url=http://www.isro.org/gslv-d3/pdf/GSLV-D3_GSAT-4%20Brochure.pdf|publisher=ISRO|access-date=15 January 2014|url-status=dead|archive-url=https://web.archive.org/web/20140207165809/http://www.isro.org/gslv-d3/pdf/GSLV-D3_GSAT-4%20Brochure.pdf|archive-date=7 February 2014}}</ref> All GSLV launches have been conducted from the [[Satish Dhawan Space Centre]] in [[Sriharikota]].

=== GSLV Mark I ===
The first developmental flight of GSLV Mark I had a 129 tonne (S125) first stage and was capable of launching around 1500&nbsp;kg into [[geostationary transfer orbit]]. The second developmental flight replaced the S125 stage with S139. It used the same solid motor with 138 tonne propellant loading. The chamber pressure in all liquid engines were enhanced, enabling a higher propellant mass and burn time. These improvements allowed GSLV to carry an additional 300&nbsp;kg of payload.<ref name="cursci-25jul01">{{cite journal|author1=R. V. Perumal|author2=B. N. Suresh|author3=D. Narayana Moorthi|author4=G. Madhavan Nair |title=First developmental flight of geosynchronous satellite launch vehicle (GSLV-D1)|journal=Current Science|date=25 July 2001|volume=81|issue=2|pages=167–174 |url=http://www.iisc.ernet.in/currsci/jul252001/167.pdf|archive-url=https://web.archive.org/web/20160305012149/http://www.iisc.ernet.in/currsci/jul252001/167.pdf|archive-date=5 March 2016}}</ref><ref name="cursci-10sep03">{{cite journal|author1=R. V. Perumal|author2=D. Narayana Moorthi|author3=N. Vedachalam|author4=G. Madhavan Nair|title=Second developmental flight of Geosynchronous Satellite Launch Vehicle |journal=Current Science|date=10 September 2003|volume=85|issue=5|pages=597–601|url=http://www.iisc.ernet.in/~currsci/sep102003/597.pdf|archive-url=https://web.archive.org/web/20180216164833/http://www.iisc.ernet.in/~currsci/sep102003/597.pdf|archive-date=16 February 2018}}</ref> The fourth operational flight of GSLV Mark I, GSLV-F06, had a longer third stage called the C15 with 15 tonne propellant loading and also employed a {{No break|4 meter}} diameter payload fairing.<ref name=GSLVF06>{{cite web|title=GSLV-F06|url=http://www.isro.gov.in/gslv-f06/gslv-f06.aspx|publisher=ISRO|access-date=9 January 2014|url-status=dead |archive-url=https://web.archive.org/web/20130810005704/http://isro.gov.in/gslv-f06/gslv-f06.aspx|archive-date=August 10, 2013}}</ref><ref>{{Cite web|title=GSLV-F06 / GSAT-5P mission brochure|url=http://isro.gov.in/gslv-f06/pdf/GSLV-F06.pdf|url-status=live|archive-url=https://web.archive.org/web/20130909115830/http://isro.gov.in/gslv-f06/pdf/GSLV-F06.pdf|archive-date=9 September 2013}}</ref>

[[File:Launch of GSLV F11 GSAT-7A from Second Launch Pad of SDSC SHAR 01.jpg|thumb|upright=1.0|left|Launch of GSLV F11 [[GSAT-7A]] from Second Launch Pad of [[Satish Dhawan Space Centre]]]]

=== GSLV Mark II ===
This variant uses an Indian cryogenic engine, the CE-7.5, and is capable of launching 2500&nbsp;kg into geostationary transfer orbit. Previous GSLV vehicles (GSLV Mark I) have used Russian cryogenic engines.<ref>{{cite web|url=http://www.spaceflightnow.com/news/n1010/12gslv/|title=India may seek international help on cryogenic engine|last=Clark|first=Stephen|date=2010-10-12|quote=Besides the new upper stage, the GSLV Mk.2 launched in April was nearly identical to previous versions of the booster|publisher=Spaceflight Now|access-date=15 July 2011}}</ref>

For launches from 2018, a 6% increased thrust version of the Vikas engine was developed. It was demonstrated on 29 March 2018 in the [[GSAT-6A]] launch second stage. It was used for the four Vikas engines first stage boosters on future missions.<ref name=sfn-20180329>{{cite news|url=https://spaceflightnow.com/2018/03/29/india-tests-upgraded-engine-tech-in-successful-communications-satellite-launch/|title=India tests upgraded engine tech in successful communications satellite launch|last=Clark|first=Stephen|publisher=Spaceflight Now|date=29 March 2018|access-date=30 March 2018}}</ref>

A 4m diameter Ogive payload fairing was developed and deployed for the first time in the [[GEO Imaging Satellite|EOS-03]] launch on 12 August 2021, although this launch was a failure due to technical anomalies with the Cryogenic Upper Stage. This will allow GSLV vehicles to accommodate larger payloads.<ref>{{Cite web|title=GSLV-F10/EOS-03 Brochure|url=https://www.isro.gov.in/gslv-f10-eos-03/gslv-f10-eos-03-brochure|access-date=14 August 2021|website=ISRO}}</ref>

As of October 2024, ISRO has stopped selling GSLV Mk II Rockets. Eight known launches are planned with [[IRNSS|NVS]] Missions, [[Indian Data Relay Satellite System|IDRSS]] Missions, [[NISAR]] Mission, etc.<ref>{{cite web |url=https://x.com/ISROSpaceflight/status/1844724481958334841?t=La5vxZzAvABlXsIcGCoHRQ&s=08 |title=ISRO has stopped selling GSLV Mk II Rockets |work=X (Formerly Twitter) |access-date=11 October 2024}}</ref><ref>{{Cite web |title=Why ISRO chose GSLV for NISAR mission despite the launch vehicle's poor track record? |url=https://www.theweek.in/news/sci-tech/2025/05/20/why-isro-chose-gslv-for-nisar-mission-despite-the-launch-vehicles-poor-track-record.html |access-date=2025-05-27 |website=The Week |language=en}}</ref>

=== RLV-OREX ===
The [[RLV Technology Demonstration Programme|Reusable Launch Vehicle Technology Demonstration program]], is a prototype [[spaceplane]] concept created by ISRO. For the Orbital return Flight experiment, a modified version of the GSLV Mk. II launcher, with the upper Cryogenic Stage replaced with the PS-4 stage from the PSLV is currently in development, as the RLV won't need all the excess energy produced by the CUS .<ref>{{Cite web |title=MSN |url=https://www.msn.com/en-in/news/other/rlv-re-entry-mission-to-use-gslv-with-pslv-last-stage-landing-gear-to-change-more/ar-BB1oSNaF |access-date=2024-06-26 |website=www.msn.com}}</ref><ref>{{Cite news |title=RLV re-entry mission to use GSLV with PSLV last stage; landing gear to change & more |url=https://timesofindia.indiatimes.com/india/rlv-re-entry-mission-to-use-gslv-with-pslv-last-stage-landing-gear-to-change-more/articleshow/111267553.cms |access-date=2024-06-26 |work=The Times of India |issn=0971-8257}}</ref>

== Launch statistics ==
{{main|List of GSLV launches}}
;Launch system status:
{{legend|#CCFFD9|Active}}
{{legend|#f9f9f9|Retired}}
{| class="wikitable" style="margin: 1em auto 1em auto;background:#fff; font-size:95%;width:60%"
|-
! Variant
! Launches
! Successes
! Failures
! Partial failures
|-style="background:#F9F9F9"
| GSLV Mk. I
| 6
| 2
| 2
| 2
|-style="background:#CCFFD9"
| GSLV Mk. II
| 10
| 8
| 2
| 0
|-style="background:#B5B5B5"
| Total {{as of|2024|February|df=|lc=yes|since=}}<ref>{{Cite web |title=ISRO GSLV NVS-1 Navic launch highlights {{!}} India launches next-gen navigational satellite |url=https://www.indiatoday.in/science/story/isro-gslv-nvs-1-navic-satellite-launch-live-updates-sriharikota-2385647-2023-05-29 |access-date=2023-05-29 |website=India Today |date=29 May 2023 |language=en}}</ref>
| 16
| 10
| 4
| 2
|}
{{clear}}
;Decade-wise summary of GSLV Launches:
{| class="wikitable" style="margin: 1em auto 1em auto;background:#fff; font-size:95%;width:60%"
|-
! Decade
! Successful
! Partial success
! Failure
! Total
|-style="background:#F9F9F9"
| 2000s
| 2
| 2
| 1
| 5
|-style="background:#F9F9F9"
| 2010s
| 6
| 0
| 2
| 8
|-style="background:#F9F9F9"
| 2020s
| 2
| 0
| 1
| 3
|-style="background:#B5B5B5"
| Total
| 10
| 2
| 4
| 16
|}

== Gallery ==
{{Gallery
|width=160 | height=170
|align=center
|File:GSLV-F05 take off.jpg
 |GSLV F05 take off
|File:GSLV F11 GSAT-7A campaign- Vehicle at Second Launch Pad 01.jpg
 |GSLV F11 vehicle at Second Launch Pad
|File:Indigenous Cryogenic Upper Stage of GSLV-F09 at Stage Preparation Facility.jpg
 |Indigenous Cryogenic Upper Stage [[CE-7.5]] of GSLV
|File:Fully integrated GSLV-F05 coming out of the Vehicle Assembly Building.jpg
 |Fully integrated GSLV-F05 coming out of the Vehicle Assembly Building
|File:Launch of GSLV F11 GSAT-7A from Second Launch Pad of SDSC SHAR 01.jpg
 |Launch of GSLV F11 from Second Launch Pad
|File:Fully Integrated GSLV-F08 inside the Vehicle Assembly Building.jpg
 |Top view of a fully Integrated GSLV-F08 inside the Vehicle Assembly Building
}}

== See also ==
{{Portal|India|Rocketry|Spaceflight}} 
* [[Small Satellite Launch Vehicle|SSLV]]
* [[Comparison of orbital launchers families]]
* [[Comparison of orbital launch systems]]
* [[Polar Satellite Launch Vehicle|PSLV]]
* [[LVM3]]
* [[Next Generation Launch Vehicle|NGLV]]
* [[Indian Space Research Organisation|ISRO]]
* [[Augmented Satellite Launch Vehicle|ASLV]]
* [[Satellite Launch Vehicle|SLV]]

== References ==
{{Reflist}}

== External links ==
{{commons category|Geosynchronous Satellite Launch Vehicle}}

* [https://web.archive.org/web/20110824113407/http://www.isro.org/launchvehicles/gslv/gslv.aspx ISRO GSLV Page]
* [https://web.archive.org/web/20091027103917/http://geocities.com/hari_ghk/gslv.htm INDIA in Space – GSLV Page]
* [https://web.archive.org/web/20070301125317/http://www.khrunichev.ru/khrunichev_eng/live/full_razg.asp?id=13182 12KRB (KVD-1) Upper Stage at Khrunichev Space Center]

{{Expendable launch systems}}
{{Indian space programme}}

[[Category:Geosynchronous Satellite Launch Vehicle| ]]
[[Category:ISRO space launch vehicles]]
[[Category:2001 in spaceflight]]
[[Category:Satish Dhawan Space Centre]]
[[Category:Vehicles introduced in 2001]]
[[Category:Expendable space launch systems]]