Indian National Satellite System (INSAT)

India's system of geostationary satellites for telecommunications, television broadcasting and weather, begun with INSAT-1A in April 1982.

Purpose

ISRO built INSAT for communication, television broadcasting and weather services. The satellites sit in geostationary orbit, so each one stays over the same spot above the equator.

Their transponders, designed at the Space Applications Centre, carry VSAT, DTH television, internet and telephone links. INSAT-3D, INSAT-3DR and INSAT-3DS serve weather, climate and disaster monitoring. In 2025, ISRO scientists used INSAT-3D data to predict lightning about 2.5 hours ahead.

Members

The series runs from INSAT-1A to INSAT-4CR, plus the weather satellites INSAT-3D, INSAT-3DR and INSAT-3DS. Newer communication satellites carry the GSAT name. The Master Control Facility at Hassan controls them all.

Timeline

• 10 April 1982: INSAT-1A launched on a US Delta rocket; ISRO records it as a satellite failure
• 30 August 1983: INSAT-1B launched from the US Space Shuttle
• 1988: INSAT-1C launched on an Ariane-3 from Kourou; it also failed
• 1992–1999: INSAT-2A to INSAT-2E launched on Ariane-4 rockets
• 2 September 2007: INSAT-4CR launched on GSLV-F04
• 17 February 2024: INSAT-3DS launched on GSLV-F14

Status

ISRO lists INSAT-3D, INSAT-3DR and INSAT-3DS as operational. The older INSAT communication satellites are no longer operational.

Sources

1. Spacecraft missions — ISRO
2. Frequently asked questions — ISRO
3. Overview, genesis and history — SAC
4. About MCF — MCF
5. Leveraging INSAT geostationary satellite for advanced lightning detection — ISRO