INSAT-3D Successfully Launched – India’s newest weather satellite

Ariane 5 Liftoff

Ariane 5 liftoff from European Spaceport in French Guiana (source: Arianespace)

This week Arianespace achieved yet another successful satellite launch from the European Spaceport in French Guiana. On this occasion, in a visually spectacular daytime launch, two new satellites – Alphasat and INSAT-3D – were delivered into orbit utilizing a heavy-lift Ariane 5 rocket.

The larger of the two satellites, Alphasat, with a liftoff mass of 6,650kg, represents Europe’s largest ever telecommunications satellite. Built through a partnership between the European Space Agency and Inmarsat, its primary purpose is to expand Inmarsat’s mobile network, which provides communication services across Europe, Africa and the Middle East.

The other satellite included in the launch, INSAT-3D, while smaller in comparison, is still a sizeable instrument, with a liftoff mass of 2060kg and measuring about the size of a small car. INSAT-3D is the latest generation weather satellite developed by the Indian Space Research Organization (ISRO), which will reside in geostationary orbit, some 36,000 km above the Indian Ocean.

While the deployment of Alphasat is significant and highly valuable, our focus here is on the geosciences and Earth observing systems; hence, let’s explore the capabilities of INSAT-3D in more detail. Building on the past success of India’s previous geostationary weather satellites, KALPANA-1 and INSAT-3A, the INSAT-3D mission incorporates many significant technologic advances. The satellite carries four main instruments as its core components:

  • Imaging System. This is a six-channel multispectral imaging system, which will provide repeat images of the Earth disk every 26 minutes. The spectral channels include: visible, short-wave infrared, two mid-wave infrared, and two thermal infrared bands. Example output products from the imager include: sea surface temperature, snow cover, fire, smoke, quantitative precipitation estimation and tropical cyclone intensity and position.
  • Atmospheric Sounding System. This is a nineteen-channel atmospheric sounding system, which will provide vertical profiles of temperature, humidity and integrated ozone. The spectral channels include one visible band and eighteen short-wave infrared, mid-wave infrared, and long-wave infrared bands. Example output products include: temperature and humidity profiles, ozone, wind index, and total perceptible water.
  • Data Relay Transponder. This instrument receives and relays important meteorological, hydrological and oceanographic data measured at remote Data Collection Platforms. Data is transmitted to centralized processing centers where the information is utilized to assist with weather forecasting operations.
  • Search and Rescue Transponder. This is a key component in satellite aided search and rescue, whereby the instrument receives and relays signals from maritime, aviation and land-based distress beacons to the Indian Mission Control Centre. The region covered by this service includes large areas of India, Bangladesh, Bhutan, Maldives, Nepal, Seychelles, Sri Lanka and Tanzania.

In the coming weeks the ISRO Master Control Facility will perform orbit maneuvers and testing of the onboard instruments. Once complete, INSAT-3D will be transitioned into operational status. We wish them great success with their ongoing efforts.

For more information on INSAT-3D:


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