GSAT

The GSAT (Geosynchronous Satellite) 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 spacecraft 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 launched numerous 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 rowspan=2 scope="row" GramSat-1 2001-015A , 10:13:00 GSLV Mk-I D2 76.85° West (2006–2009) 0.9° Experimental Launch placed it into lower than planned orbit, which prevented it from fulfilling its primary communications mission. GSAT-2 rowspan=2 scope="row" GramSat-2 2003-018A , 11:28:00 GSLV Mk-I D3 47.95° East 2.43° Experimental Second experimental attempt. GSAT-3 rowspan=2 scope="row" EduSat 2004-036A , 10:31:00 GSLV Mk-I F01 74° East 2.71° 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 rowspan=2 scope="row" HealthSat , 10:57:00 GSLV Mk-II D3 82° East Communication and Navigation Failed to reach orbit due to malfunction of the Fuel Booster Turbo Pump (FBTP) of the cryogenic upper stage. GSAT-5P rowspan=2 colspan=2 scope="row" , 10:34:00 GSLV Mk-I F06 55° East Replacement of INSAT-3E Rebuilt from GSAT-5 (INSAT-4D) Vehicle was destroyed by range safety officer after loss of control over liquid-fueled boosters. GSAT-6 INSAT-4E rowspan=2 scope="row" 2015-041A , 11:22:00 GSLV Mk-II D6 83° East 1.4° 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 rowspan=2 colspan=2 scope="row" 2018-027A , 11:26:00 GSLV Mk-II F08 83° East 2.8° 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. GSAT-7 INSAT-4F Rukmini 2013-044B , 20:30:00 Ariane 5 ECA VA-215 74° East 0.06° 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 rowspan=2 scope="row" Angry Bird 2018-105A , 10:40:00 GSLV Mk-II F11 63° East 0.0° Military Advanced military communications satellite meant exclusively for the Indian Air Force. GSAT-7R rowspan=2 scope="row" CMS-03 2025-249B , 11:56:00 LVM3 M5 93.5° East 0.2° Military Replacement for GSAT-7 Rukmini for Indian Navy. GSAT-8 INSAT-4G GramSat-8 2011-022A , 20:38:00 Ariane 5 ECA VA-202 55° East 1.6° 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 rowspan=2 scope="row" South Asia Satellite 2017-024A , 11:27:00 GSLV MK-II F09 48° East 0.0413° 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 rowspan=2 colspan=2 scope="row" 2012-051B Ariane 5 ECA VA-209 83° East 0.1° Navigation To augment telecommunication, direct-to-home and radio navigation services. GSAT-11 rowspan=2 colspan=2 scope="row" 2018-100B , 20:37:00 Ariane 5 ECA VA-246 74° East 0.0° Telecom Aimed at providing advanced telecom and direct-to-home services in the country. Heaviest satellite built by India at the time. GSAT-12 rowspan=2 scope="row" GramSat-12 2018-100B Ariane 5 ECA VA-246 74° East 0.0° 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 rowspan=2 scope="row" CMS-01 2020-099A , 11:18:00 PSLV-XL C50 83° East 0.1° Multipurpose Replacement of GSAT-12. GSAT-14 rowspan=2 colspan=2 scope="row" 2014-001A , 10:48:00 GSLV Mk-II D5 75° East 0.1° Communications Replacement of GSAT-3. GSAT-15 rowspan=2 colspan=2 scope="row" 2015-065A , 21:34:07 Ariane 5 ECA VA-227 93.5° East 0.0728° 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 rowspan=2 colspan=2 scope="row" 2014-078A , 20:40:00 Ariane 5 ECA VA-221 55° East 0.0° 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 rowspan=2 colspan=2 scope="row" 2017-040B , 21:15:00 Ariane 5 ECA VA-238 93.5° East 0.0° 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. GSAT-18 rowspan=2 colspan=2 scope="row" 2016-060A , 20:30:00 Ariane 5 ECA VA-231 74° East 0.1° Communications To provide services in Normal C-band, Upper Extended C-band and Ku bands of the frequency spectrum. GSAT-19 rowspan=2 colspan=2 scope="row" 2017-031A , 11:58:00 LVM3 D1 48° East 0.101° 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. GSAT-20 rowspan=2 scope="row" GSAT-N2 2024-214A , 18:30:00 Falcon 9 Block 5 F9-398 55° East 0.101° Communications Entire capacity of the satellite leased to Dish TV. GSAT-24 rowspan=2 scope="row" GSAT-N1 2022-067A , 21:50:00 Ariane 5 ECA VA-257 48° East TBD Communications The entire capacity onboard GSAT-N1 satellite would be leased to Tata Play. GSAT-29 rowspan=2 colspan=2 scope="row" 2018-089A , 11:38:00 LVM3 D2 55° East 0.0° Communications The mission aims at providing high-speed bandwidth to Village Resource Centres (VRC) in rural areas. GSAT-30 rowspan=2 colspan=2 scope="row" 2020-005A , 21:05:00 Ariane 5 ECA VA-251 83° East 0.0° Communications Replacement satellite for INSAT-4A. GSAT-31 rowspan=2 colspan=2 scope="row" 2019-007B Ariane 5 ECA VA-251 48° East 0.1° Telecom This is the 40th communication satellite launched by ISRO.

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 rowspan=2 colspan=2 scope="row" 2020s GSLV Mk-II TBD Military Military communication satellite for Indian Army. GSAT-7C rowspan=2 colspan=2 scope="row" 2020s GSLV Mk-II TBD Military Military communication satellite for Indian Air Force. GSAT-7S rowspan=2 colspan=2 scope="row" 2020s GSLV Mk-II TBD Military Military communication satellite for Indian Air Force GSAT-22 rowspan=2 colspan=2 scope="row" 2020s LVM3 TBD Communication Communication satellite. GSAT-23 rowspan=2 colspan=2 scope="row" 2020s LVM3 TBD TBD GSAT-32 rowspan=2 scope="row" GSAT-N3 Q2 2026 LVM3 Communication Replacement of GSAT-6A.

Statistics

Launches by year

Launches by rocket

Launches by country

Country Launches Successes Failures Partial failures 12 12 0 0 14 10 3 1 1 1 0 0 Total

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