Insat (Indian National Satellite System) was a multipurpose satellite system for telecommunications, broadcasting, meteorology and search and rescue services. Commissioned in 1983, Insat was the largest domestic communication system in the Asia-Pacific Region, and was a joint venture of the Indian Department of Space (DOS), Department of Telecommunications, India Meteorological Department, All India Radio and Doordarshan. As of 2004 the Insat space segment consisted of: Insat-1D, last of the Insat-1 series launched in 1990; three ISRO-built satellites, Insat-2A launched in July 1992, Insat-2B launched in July 1993 and Insat-2C launched on December 7, 1995; Insat-2DT acquired from Arabsat; Insat-2E launched on April 3,1999; Insat-3B launched on March 22nd 2000; Insat-3C launched on January 24th 2002; Insat-3A launched on April 10th 2003; Insat-3E launched on September 28th 2003; and Gsat-2 and Gsat-3. As of mid-2004 ISRO leased eleven 36 MHz equivalent units of C-band capacity on board Insat-2E to Intelsat.
Insat 1A
It carried transponders for domestic communications. Operational multipurpose satellite for telecommunications, meteorological, imaging and data relay, radio and television programme distribution and direct television broadcasting for community reception. Geosynchronous orbit longitude 74 E.
Insat 1B
It carried transponders for domestic communications. Operational multipurpose satellite for telecommunications, meteorological imaging and data relay, radio and television programme distribution and direct television broadcasting for community reception. Geostationary longitude 74.0 +/ – 0.1 deg E. Deployment from US Space Transportation System flight no 8, orbiter Challenger, on 31 Aug 1983. Positioned in geosynchronous orbit at 74 deg E in 1983-1992; 93 deg E in 1992-1993 As of 26 August 2001 located at 125.27 deg E drifting at 0.152 deg E per day. As of 2007 Mar 10 located at 80.35E drifting at 0.392E degrees per day.