GSAT

This article is about the Indian telecommunications and broadcasting satellites. For the navigation satellites, see Galileo navigation system. For the algorithm for propositional Boolean satisfiability, see WalkSAT. For the Taiwanese university entrance exam, see General Scholastic Ability Test.

Not to be confused with G Sat, a Philippine satellite television provider.

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

The GSAT-7A, a military communications satellite, in deployed configuration
Manufacturer	ISRO
Country of origin	India
Operator	INSAT
Applications	Communications
Specifications
Regime	Geostationary orbit
Production
Status	In service
On order	6
Built	27
Launched	27
Operational	20
Retired	3
Failed	3
Lost	1
Maiden launch	GSAT-1 (GramSat-1) 18 April 2001
Last launch	GSAT-7R (CMS-03) 2 November 2025

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, K_u, K_a, 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 K_a 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	—	GramSat-1[2]	2001-015A	18 April 2001, 10:13:00	GSLV Mk-I D2	1,540 kg (3,400 lb)	76.85° West (2006–2009) [a]	0.9°	Launch failure	Experimental
		Launch placed it into lower than planned orbit, which prevented it from fulfilling its primary communications mission.
GSAT-2	—	GramSat-2[3]	2003-018A	8 May 2003, 11:28:00	GSLV Mk-I D3	1,825 kg (4,023 lb)	47.95° East	2.43°	Successful	Experimental
		Second experimental attempt.
GSAT-3	—	EduSat	2004-036A	20 September 2004, 10:31:00	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	—	HealthSat	—	15 April 2010, 10:57:00	GSLV Mk-II D3	2,220 kg (4,890 lb)	82° East	—	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	—		—	25 December 2010, 10:34:00	GSLV Mk-I F06	2,310 kg (5,090 lb)	55° East	—	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	—	2015-041A	27 August 2015, 11:22:00	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	—		2018-027A	29 March 2018, 11:26:00	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	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	—	Angry Bird	2018-105A	19 December 2018, 10:40:00	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	—	CMS-03	2025-249B	2 November 2025, 11:56:00	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	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	—	South Asia Satellite	2017-024A	5 May 2017, 11:27:00	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	—		2012-051B	29 September 2012	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	—		2018-100B	4 December 2018, 20:37:00	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	—	GramSat-12[10]	2018-100B	4 December 2018	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	—	CMS-01	2020-099A	17 December 2020, 11:18:00	PSLV-XL C50	1,425 kg (3,142 lb)	83° East	0.1°	Operational	Multipurpose
			Replacement of GSAT-12.
GSAT-14	—		2014-001A	5 January 2014, 10:48:00	GSLV Mk-II D5	1,982 kg (4,370 lb)	75° East	0.1°	Operational	Communications
			Replacement of GSAT-3.
GSAT-15	—		2015-065A	10 November 2015, 21:34:07	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	—		2014-078A	6 December 2014, 20:40:00	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	—		2017-040B	28 June 2017, 21:15:00	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	—		2016-060A	5 October 2016, 20:30:00	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	—		2017-031A	5 June 2017, 11:58:00	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	—	GSAT-N2[15]	2024-214A	18 November 2024, 18:30:00	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	—	GSAT-N1	2022-067A	22 June 2022, 21:50:00	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	—		2018-089A	14 November 2018, 11:38:00	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	—		2020-005A	17 January 2020, 21:05:00	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	—		2019-007B	6 February 2019	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	—		2020s	GSLV Mk-II	TBD	Planned	Military
Military communication satellite for Indian Army.[21]
GSAT-7C	—		2020s	GSLV Mk-II	TBD	Planned	Military
			Military communication satellite for Indian Air Force.[22]
GSAT-7S	—		2020s	GSLV Mk-II	TBD	Planned	Military
			Military communication satellite for Indian Air Force[citation needed]
GSAT-22	—		2020s	LVM3	TBD	Planned	Communcation
			Communcation satellite.[23]
GSAT-23	—		2020s	LVM3	TBD	Planned	TBD
			[23]
GSAT-32	—	GSAT-N3	Q2 2026	LVM3	4,500 kg (9,900 lb)	Planned	Communication
			Replacement of GSAT-6A.[23]

Statistics

As of 23 November 2025

By year

1

2

3

4

5

2001

2005

2010

2015

2020

2025

2030

•   Success
•   Partial failure
•   Failure
•   Planned

By rocket

3

6

9

12

15

Ariane 5

GSLV

LVM3

PSLV

Falcon 9 Block 5

•   Ariane 5
•   GSLV MKI
•   GSLV MKII
•   LVM3
•   PSLV
•   Falcon 9 Block 5

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		27	23	3	1

See also

• Spaceflight portal
• India portal

• Polar Satellite Launch Vehicle (PSLV)
• Geosynchronous Satellite Launch Vehicle (GSLV)
• List of Indian satellites
• List of Satish Dhawan Space Centre launches