| INSAT-1D (Full name: Indian National Satellite - 1D) | |
| Mission Type: | Communications, Cloud Observation |
| Operator: | INSAT |
| Cospar Id: | 1990-051A |
| Satcat: | 20643 |
| Mission Duration: | 7 years |
| Spacecraft Type: | INSAT-1 |
| Manufacturer: | Ford Aerospace |
| Launch Mass: | 1190kg (2,620lb) (Lift - off Mass)[1] |
| Dry Mass: | 550kg (1,210lb) |
| Power: | 1000 W (Solar array); Nominal Power: 1200.0 W |
| Launch Date: | June 12, 1990, 05:52:00 UTC [2] [3] |
| Launch Rocket: | Delta 4925[4] |
| Launch Site: | Cape Canaveral LC-17B |
| Launch Contractor: | NASA |
| Deployment Date: | UTC |
| Disposal Type: | Decommissioned (mission life over) |
| Orbit Epoch: | 14 November 2013, 15:52:38 UTC[5] |
| Orbit Reference: | Geocentric |
| Orbit Regime: | Geostationary |
| Orbit Periapsis: | 35741km (22,208miles) |
| Orbit Apoapsis: | 35846km (22,274miles) |
| Orbit Inclination: | 14.30 degrees |
| Orbit Semimajor: | 42164.88km (26,200.04miles) |
| Orbit Eccentricity: | 0.0012393 |
| Orbit Period: | 23.93 hours |
| Orbit Longitude: | 83° east |
| Apsis: | gee |
INSAT-1D was 4th and the concluding multipurpose geostationary satellite of the INSAT-1 (first-generation seven-year responsibility for the operation of the INSAT space segment.[6]
But the success of this launch meant a lot to India - a country that was setting up its national computer networks. Relying on a lot of communication circuits, microwave, coaxial, and fibre-optic telecommunication links throughout the country causes a huge problem; and thus the Indian Space Research Organisation (ISRO) planned at the start of the INSAT-1 series to always have at least two satellites in space to meet the increasing demand of telecommunication links for India's civilian community. INSAT-1A and INSAT-1C had already faced immature death and their plans had suffered a serious setback. Another satellite INSAT-1B, launched in 1983, exceeded its planned seven-year working life.[7]
INSAT 1D was built by Ford Aerospace (now Loral Inc) for the Indian National Satellite System.[8] Initially, the launch was scheduled for 29 June 1989. Unfortunately, 10 days before that, during launch preparation, a launchpad hoist cable broke and a crane hook fell on it damaging its C-band reflector. The fully insured satellite was repaired by Ford Aerospace at a reported cost of $10 million. But that mishap was followed by solar panel damage of cost $150,000 suffered during the 1989 San Francisco earthquake. The satellite was finally launched from Launch Complex 17B, Cape Canaveral Space Force Station, United States with the Delta 2 rocket. It had a 7-year life expectancy.[9]
The satellite was box-shaped, measuring 2.18xx. A solar sail and 11.5m2 solar panel extended overall length to 19.4m (63.6feet) when deployed. It was housed 12 C-band transponders for telephone and data communications and two S-band transponders for direct broadcast service. A very high-resolution radiometer (VHRR) was installed for meteorological imagery for long-term weather forecasting, storm warning and resource management.
INSAT-1D played a vital role in replacing INSAT-1B. Moreover, at that moment India already had hired Arabsat's 12 transponders at high cost (the rate of $800,000 per transponder per year). Failure of the 1D mission would compel the government to hire more transponders.