The Indian National Satellite (INSAT) system was commissioned with the launch of
INSAT-1B in August 1983 (
INSAT-1A, the first satellite was launched in April 1982 but could not fulfil the mission). INSAT system ushered in a revolution in India's
television and
radio broadcasting,
telecommunications and
meteorological sectors. It enabled the rapid expansion of TV and modern telecommunication facilities to even the remote areas and off-shore islands. Together, the system provides transponders in C, Extended C and Ku bands for a variety of communication services. Some of the INSATs also carry instruments for meteorological observation and data relay for providing meteorological services. KALPANA-1 is an exclusive meteorological satellite. The satellites are monitored and controlled by Master Control Facilities that exist in
Hassan and
Bhopal.
INSAT-1 series The first generation of INSAT satellites, developed with
NASA assistance, included INSAT-1A, 1B, 1C, and 1D, with all of them being launched in the 1980s. Their success established India's capability to operate a national communications and weather-monitoring satellite fleet. 1B, launched in 1983, became the first fully operational Indian
GEO communications satellite.
INSAT-2 series The INSAT-2 series during the 1990s, marked the shift to fully indigenous satellite design. Models included INSAT-2A, 2B, SC, 2D, and 2E, each offering expanded transponder capacity, improved meteorological imaging and enhanced reliability.
INSAT-3 series Launched between 2000 and 2003, the INSAT-3 series introduced larger satellites with advanced payloads. 3B was for business communication, 3C for national telecommunication backbone, 3A and 3D for meteorology and disaster warning, and 3E for and data relay.
INSAT-4 series The INSAT-4 generation launched between 2005 and 2010 focused on high-power Ku-band DTH broadcasting. 4A was India's first dedicated DTH satellite, 4B and 4CR was for communication and replacement missions, and 4E (also known as GSAT-6) had a large S-band antenna for mobile communications. INSAT-4 satellites were eventually supplemented by the newer GSAT series.
Transition into GSAT Many communication satellites which were originally conceived under the INSAT umbrella were reclassified as GSAT as ISRO shifted to newer satellite bus platforms of I-2K and I-3K. INSAT continues to focus mainly on meteorology and disaster management, while GSAT handles broadband, telecom, and strategic communication. == List of INSAT satellites ==