Engineering:GSAT

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The GSAT (Geosynchronous Satellite)[1] series is a family of Indian communications satellites, indigenously developed and operated by the ISRO. The prorgamme was initiated in the early 2000s to create indigenous, multi-purpose, geostationary spacecrafts capable of supporting India's growing needs in telecommunications, broadcasting, broadband, emergency management, reconnaissance and navigation. The programme was supported by the development of Geosynchronous Satellite Launch Vehicle.

GSAT satellites include a total of 168 transponders (out of which 95 are leased out to provide services to broadcasters), and operate primarily in C, Extended C, Ku, Ka, S and L bands, with payload configurations tailored for civilian, commercial, and strategic needs. The development of both GSAT satellites and the GSLV launch system represents India's transition from dependence on foreign-built INSAT spacecraft to self-reliant national communications capability. As of 21 November 2025, 27 GSAT satellites manufactured by ISRO have been launched, out of which 20 are in service and six more being planned.

History

The GSAT programme began as part of ISRO's efforts to supplement the aging Indian National Satellite System (INSAT) fleet and reduce reliance on leased transponders from foreign satellites. Early missions of GSAT-1 (2001) and GSAT-2 (2003) were launched to test indigenous bus designs, power systems and communication payloads.

Between 2004 and 2020, ISRO launchd numerious GSAT satellites with varied roles including direct-to-home broadcasting support, tele-education and tele-medicine, high-throughput broadband, navigation augmentation for aviation, dedicated military communication.

Recent missions focus on high-bandwidth Ka band systems, secure strategic communication and navigation augmentation under GPS-aided GEO augmented navigation (GAGAN). Several satellites use advanced I-2K, I-3K and 1-6K satellite bus platforms designed for long life and high payload capacity.

Launched

The following is a list of launched GSAT satellites and their status. As of 2025, there were 27 GSAT launches with 20 of them being operational.

Launched GSAT satellites
GSAT series INSAT Series Other name(s) COSPAR ID Launch date and time,
UTC 		Launch vehicle Lift-off mass Orbital parameters Outcome Purpose
Longitude Inclination
GSAT-1 N/A GramSat-1[2] 2001-015A 18 April 2001, 10:13:00 India GSLV Mk-I D2 1,540 kg (3,400 lb) 76.85° West (2006–2009) [lower-alpha 1] 0.9° Launch failure Experimental
Launch placed it into lower than planned orbit, which prevented it from fulfilling its primary communications mission.
GSAT-2 N/A GramSat-2[3] 2003-018A 8 May 2003, 11:28:00 India GSLV Mk-I D3 1,825 kg (4,023 lb) 47.95° East 2.43° Successful Experimental
Second experimental attempt.
GSAT-3 N/A EduSat 2004-036A 20 September 2004, 10:31:00 India GSLV Mk-I F01 1,950 kg (4,300 lb) 74° East 2.71° Successful Educational
Mainly intended to meet the demand for an interactive satellite-based distance education system for the country. Decommissioned on 30 September 2010 after six years of operation.
GSAT-4 N/A HealthSat N/A 15 April 2010, 10:57:00 India GSLV Mk-II D3 2,220 kg (4,890 lb) 82° East N/A Launch failure Communication and Navigation
Failed to reach orbit due to malfunction of the Fuel Booster Turbo Pump (FBTP) of the cryogenic upper stage.
GSAT-5P N/A N/A 25 December 2010, 10:34:00 India GSLV Mk-I F06 2,310 kg (5,090 lb) 55° East N/A Launch failure Replacement of INSAT-3E
Rebuilt from GSAT-5 (INSAT-4D)[4] Vehicle was destroyed by range safety officer after loss of control over liquid-fueled boosters.
GSAT-6 INSAT-4E N/A 2015-041A 27 August 2015, 11:22:00 India GSLV Mk-II D6 2,132 kg (4,700 lb) 83° East 1.4° Operational Multimedia
A multimedia mobile satellite system; offers a Satellite Digital Multimedia Broadcasting (S-DMB) service, via mobile phones and mobile video/audio receivers for vehicles; can also be utilized for strategic and social applications.
GSAT-6A N/A 2018-027A 29 March 2018, 11:26:00 India GSLV Mk-II F08 2,140 kg (4,720 lb) 83° East 2.8° Communication failure Communication
Communication with the satellite was lost after the second orbit raising manoeuvre. Efforts are on to re-establish link but at this point it remains incommunicado.[5]
GSAT-7 INSAT-4F[6] Rukmini 2013-044B 29 August 2013, 20:30:00 France Ariane 5 ECA VA-215 2,650 kg (5,840 lb) 74° East 0.06° Operational Military
According to defense experts, it was built to enable the Indian Navy to acquire blue water capabilities and remove dependence on foreign satellites like Inmarsat, which provide communication services to its ships.
GSAT-7A N/A Angry Bird 2018-105A 19 December 2018, 10:40:00 India GSLV Mk-II F11 2,250 kg (4,960 lb) 63° East 0.0° Operational Military
Advanced military communications satellite meant exclusively for the Indian Air Force.
GSAT-7R N/A CMS-03 2025-249B 2 November 2025, 11:56:00 India LVM3 M5 4,410 kg (9,720 lb) 93.5° East 0.2° Operational Military
Replacement for GSAT-7 Rukmini for Indian Navy.[7]
GSAT-8 INSAT-4G GramSat-8[8] 2011-022A 20 May 2011, 20:38:00 France Ariane 5 ECA VA-202 3,093 kg (6,819 lb) 55° East 1.6° Operational Navigation
To augment the capacity in the INSAT system; the GAGAN payload provides the Satellite Based Augmentation System (SBAS), through which the accuracy of the positioning information obtained from the IRNSS (NAVIC) satellites is improved by a network of ground-based receivers and made available to users in the country through the geostationary satellites.
GSAT-9 N/A South Asia Satellite 2017-024A 5 May 2017, 11:27:00 India GSLV MK-II F09 2,330 kg (5,140 lb) 48° East 0.0413° Operational Navigation
Carried GAGAN navigation payload, a regional IRNSS (NAVIC) navigational system developed by India, that provides navigational services to the security forces and air traffic control organizations.
GSAT-10 N/A 2012-051B 29 September 2012 France Ariane 5 ECA VA-209 3,435 kg (7,573 lb) 83° East 0.1° Operational Navigation
To augment telecommunication, direct-to-home and radio navigation services.[9]
GSAT-11 N/A 2018-100B 4 December 2018, 20:37:00 France Ariane 5 ECA VA-246 5,854 kg (12,906 lb) 74° East 0.0° Operational Telecom
Aimed at providing advanced telecom and direct-to-home services in the country. Heaviest satellite built by India at the time.
GSAT-12 N/A GramSat-12[10] 2018-100B 4 December 2018 France Ariane 5 ECA VA-246 5,854 kg (12,906 lb) 74° East 0.0° Successful Multipurpose
Replacement of the INSAT-3B; provided services like tele-education, telemedicine, disaster management support and satellite internet access. Only GSAT satellite to be launched by PSLV.
GSAT-12R N/A CMS-01 2020-099A 17 December 2020, 11:18:00 India PSLV-XL C50 1,425 kg (3,142 lb) 83° East 0.1° Operational Multipurpose
Replacement of GSAT-12.
GSAT-14 N/A 2014-001A 5 January 2014, 10:48:00 India GSLV Mk-II D5 1,982 kg (4,370 lb) 75° East 0.1° Operational Communications
Replacement of GSAT-3.
GSAT-15 N/A 2015-065A 10 November 2015, 21:34:07 France Ariane 5 ECA VA-227 3,100 kg (6,800 lb) 93.5° East 0.0728° Operational Communications
Similar to GSAT-10 satellite; to augment the capacity of transponders to provide more bandwidth for direct-to-home television and VSAT services.
GSAT-16 N/A 2014-078A 6 December 2014, 20:40:00 France Ariane 5 ECA VA-221[11] 3,150 kg (6,940 lb) 55° East 0.0° Operational Communications
The communication payloads provide a combination of total 48 transponders across the three frequency bands (24 in Normal C band, 12 in Extended-C band and 12 in Ku-band) along with a Ku-band beacon transmitter, which is the highest for an Indian satellite. The spacecraft will be co-located with GSAT-8 at 55° East.
GSAT-17 N/A 2017-040B 28 June 2017, 21:15:00 France Ariane 5 ECA VA-238 3,477 kg (7,665 lb) 93.5° East 0.0° Operational Communications
Payload includes 24 C-band, 2 lower C-band, 12 upper C-band, 2 CxS (C-band up/S-band down), and 1 SxC (S-band up/C-band down) transponders as well as a dedicated transponder for data relay (DRT) and search-and-rescue (SAR) services.[12]
GSAT-18 N/A 2016-060A 5 October 2016, 20:30:00 France Ariane 5 ECA VA-231 3,404 kg (7,505 lb) 74° East 0.1° Operational Communications
To provide services in Normal C-band, Upper Extended C-band and Ku bands of the frequency spectrum.[13]
GSAT-19 N/A 2017-031A 5 June 2017, 11:58:00 India LVM3 D1 3,136 kg (6,914 lb) 48° East 0.101° Operational Communications
Rather than traditional transponders, GSAT-19 carries four Ku/Ka-band forward link beams and four Ku/Ka-band return link beams, providing much higher data throughput than India's previous communications satellites.[14]
GSAT-20 N/A GSAT-N2[15] 2024-214A 18 November 2024, 18:30:00 United States Falcon 9 Block 5 F9-398 5,300 kg (11,700 lb) 55° East 0.101° Operational Communications
Entire capacity of the satellite leased to Dish TV.[16][17]
GSAT-24 N/A GSAT-N1 2022-067A 22 June 2022, 21:50:00 France Ariane 5 ECA VA-257 4,181 kg (9,218 lb) 48° East TBD Operational Communications
The entire capacity onboard GSAT-N1 satellite would be leased to Tata Play.
GSAT-29 N/A 2018-089A 14 November 2018, 11:38:00 India LVM3 D2 3,423 kg (7,546 lb) 55° East 0.0° Operational Communications
The mission aims at providing high-speed bandwidth to Village Resource Centres (VRC) in rural areas.[18]
GSAT-30 N/A 2020-005A 17 January 2020, 21:05:00 France Ariane 5 ECA VA-251 3,547 kg (7,820 lb) 83° East 0.0° Operational Communications
Replacement satellite for INSAT-4A.[19]
GSAT-31 N/A 2019-007B 6 February 2019 France Ariane 5 ECA VA-251 2,536 kg (5,591 lb) 48° East 0.1° Operational Telecom
This is the 40th communication satellite launched by ISRO.[20]

Planned

The following is a list of six planned GSAT launches.

Planned GSAT Satellites
GSAT series INSAT Series Other name(s) Launch date Launch vehicle Lift-off mass Status Purpose
GSAT-7B N/A 2020s India GSLV Mk-II TBD Planned Military
Military communication satellite for Indian Army.[21]
GSAT-7C N/A 2020s India GSLV Mk-II TBD Planned Military
Military communication satellite for Indian Air Force.[22]
GSAT-7S N/A 2020s India GSLV Mk-II TBD Planned Military
Military communication satellite for Indian Air Force[citation needed]
GSAT-22 N/A 2020s India LVM3 TBD Planned Communcation
Communcation satellite.[23]
GSAT-23 N/A 2020s India LVM3 TBD Planned TBD
[23]
GSAT-32 N/A GSAT-N3 Q2 2026 India LVM3 4,500 kg (9,900 lb) Planned Communication
Replacement of GSAT-6A.[23]

Statistics

Template:Updated

By year

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By rocket

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By country


Country Launches Successes Failures Partial
failures
 France 12 12 0 0
 India 14 10 3 1
 United States 1 1 0 0
Total Template:Sum Template:Sum Template:Sum Template:Sum

See also

References

Notes
  1. ↑ Previously: 73° West (2000) and 99° West (2000–2006)
References
  1. ↑ "ISRO GeoStationary Satellites". http://isro.org/satellites/geostationary.aspx. 
  2. ↑ "GSAT 1". NASA. 16 August 2013. https://nssdc.gsfc.nasa.gov/nmc/spacecraft/display.action?id=2001-015A. 
  3. ↑ "GSAT 2". NASA. 16 August 2013. https://nssdc.gsfc.nasa.gov/nmc/spacecraft/display.action?id=2003-018A. 
  4. ↑ "GSat 5 (Insat 4D)". Gunter's Space Page. 29 March 2017. http://space.skyrocket.de/doc_sdat/gsat-5.htm. 
  5. ↑ "The second orbit raising operation of GSAT-6A satellite has been successfully carried out by LAM Engine firing for about 53 minutes on March 31, 2018 in the morning. - ISRO". https://www.isro.gov.in/update/01-apr-2018/second-orbit-raising-operation-of-gsat-6a-satellite-has-been-successfully-carried. 
  6. ↑ "GSAT 7". NASA. 16 August 2013. https://nssdc.gsfc.nasa.gov/nmc/spacecraft/display.action?id=2013-044B. 
  7. ↑ Pubby, Manu (18 July 2019). "Navy to buy Rs 1,589 crore satellite from ISRO". Economic Times. https://economictimes.indiatimes.com/news/defence/navy-to-buy-rs-1589-crore-satellite-from-isro/articleshow/70283927.cms. 
  8. ↑ "GSAT 8". NASA. 16 August 2013. https://nssdc.gsfc.nasa.gov/nmc/spacecraft/display.action?id=2011-022A. 
  9. ↑ "GSAT 10". NASA. 16 August 2013. https://nssdc.gsfc.nasa.gov/nmc/spacecraft/display.action?id=2012-051B. 
  10. ↑ "GSAT 12". NASA. 16 August 2013. https://nssdc.gsfc.nasa.gov/nmc/spacecraft/display.action?id=2011-034A. 
  11. ↑ "Ariane 5 delivers DIRECTV-14 and GSAT-16 to orbit on Arianespace's latest mission success". http://www.arianespace.com/news-mission-update/2014/1245.asp. 
  12. ↑ "Annual Report 2015-2016". Indian Space Research Organisation. December 2015. p. 28. http://www.isro.gov.in/sites/default/files/article-files/right-to-information/annual_report-15-16.pdf. 
  13. ↑ "GSAT-18 launched successfully on board Ariane-5 from Kourou in French Guiana". 2016-10-06. http://indianexpress.com/article/technology/science/isro-india-telecommunications-satellite-gsat-18-launch-french-guiana-3067595/. 
  14. ↑ "Now, ISRO successfully puts GSAT-19 satellite in orbit with GSLV Mk-III". The New Indian Express. 5 June 2017. http://indianexpress.com/article/india/isro-gsat-19-satellite-launch-live-updates-india-attempts-to-put-3136-kg-satellite-in-orbit-4689969/. 
  15. ↑ "SpaceX launches communications satellite for India" (in en). https://mynews13.com/fl/orlando/space/2024/11/18/spacex-nsil-gsat-n2-mission. 
  16. ↑ "SpaceX launches India’s GSAT-N2 satellite on Falcon 9 rocket from Cape Canaveral – Spaceflight Now" (in en-US). https://spaceflightnow.com/2024/11/18/live-coverage-spacex-to-launch-indias-gsat-n2-satellite-on-falcon-9-rocket-from-cape-canaveral/. 
  17. ↑ "Falcon 9 Block 5 - GSAT-20". https://nextspaceflight.com/launches/details/753. 
  18. ↑ "ISRO successfully launches the GSAT-29 satellite from Satish Dhawan Space Center in Sriharikota on Wednesday" (in en). Nov 14, 2018. https://bangaloremirror.indiatimes.com/bangalore/others/isro-successfully-launches-the-gsat-29-satellite-from-satish-dhawan-space-center-in-sriharikota-on-wednesday/articleshow/66621815.cms. 
  19. ↑ "India's communication satellite GSAT-30 launched successfully". ISRO. https://www.isro.gov.in/update/17-jan-2020/press-release-india%E2%80%99s-communication-satellite-gsat-30-launched-successfully. 
  20. ↑ "India's 40th Communication Satellite, GSAT-31, Launched". NDTV. https://www.ndtv.com/india-news/indias-40th-communication-satellite-gsat-31-launched-1988977. 
  21. ↑ "Military communication satellite for Indian Army approved". Deccen Herald. 22 March 2022. https://www.deccanherald.com/national/military-communication-satellite-for-indian-army-approved-1093746.html. 
  22. ↑ "Defence ministry clears proposal for GSAT-7C satellite for IAF: A look at other military satellites in India". Firstpost. 24 November 2021. https://www.firstpost.com/india/defence-ministry-clears-proposal-for-gsat-7c-satellite-for-iaf-a-look-at-other-military-satellites-in-india-10160861.html. 
  23. ↑ 23.0 23.1 23.2 Kumar, Chethan (5 October 2021). "Space PSU NSIL to launch 4 more demand-driven communication satellites". The Times of India. https://timesofindia.indiatimes.com/home/science/space-psu-nsil-to-launch-4-more-demand-driven-communication-satellites/articleshow/86790835.cms. 



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