INSAT-3D. Photo Credit: ISRO

The INSAT-3D is an advanced meteorological satellite built to improve domestic weather forecasting and track cyclones and monsoons originating from the Bay of Bengal and Arabian Sea. 

The satellite was launched on Ariane-5 flight heavy lift launcher flight VA214 from the spaceport at Kourou, French Guiana on July 25 (Early hours July 26 in India) along with the 6.6 metric ton Alphasat, the heaviest European telecommunications satellite ever built.

Alphasat rode in Ariane 5's upper payload position, and INSAT-3D in the lower portion of the payload "stack."

Orbital Parameters

The satellite was placed in Geosynchronous orbit after three orbit raising maneuvers commanded from ISRO's Master Control Facility at Hassan. 

The Orbital parameters of INSAT-3D are: 

Perigee:         35,469 km
Apogee:         35,799 km
Inclination:     0.23 deg
Orbital Period: 23 hr 48 minutes

According to an ISRO press release, there was an anomalous behavior of the satellite after the deployment of its solar panel. However, the Mission Operations Team of ISRO could immediately bring the Satellite into normalcy using the prescribed contingency procedures and then resume the orbit-raising operations. 

INSAT-3D is now moving towards its final geostationary orbital location of 82 degree East longitude and on August 6, 2013 it will reach this destination. 

Subsequently, the two meteorological payloads (Imaging System, Atmospheric Sounder), as well as the two Transponders (designed for the Meteorological Data Relay and Satellite-aided Search and Rescue system) will be activated by August 8, 2013.

The nearly 2.1 ton satellite was placed in an elliptical Geosynchronous Transfer Orbit (GTO) very close to the intended orbit after a flight of 32 minutes and 48 seconds.

Parameter (Unit) Targeted Achieved

Perigee (km) 249.9         249.9
Apogee (km) 35880 35923
Orbital Inclination with respect to Equatorial plane (deg) 3.501 3.495

Soon after the separation from the Ariane-5's upper cryogenic stage, the satellite's solar panel automatically deployed and ISRO's Master Control Facility (MCF) at Hassan in Karnataka took over the control of INSAT-3D.

Preliminary health checks of all the subsystems of INSAT-3D bus were performed and the satellite's health is satisfactory. 

In the coming days, the satellite will be eased into a 36,000 km 82 deg East Geostationary Orbit through multiple orbit raising maneuvers using its onboard propulsion system.

ISRO plans to turn on and extensively test the meteorological payloads of INSAT-3D in the second week of August 2013.


INSAT-3D carries four payloads - Imager, Sounder, Data Relay Transponder and Satellite Aided Search & Rescue payload. 

The six channel imager can take weather pictures of the Earth and has improved features compared to the payloads in KALPANA-1 and INSAT-3A, the two Indian Geostationary Satellites providing weather services for the past one decade. 

The 19 channel sounder payload of INSAT-3D adds a new dimension to weather monitoring through its atmospheric sounding system, and provides vertical profiles of temperature, humidity and integrated ozone. 

Data relay transponder, the third payload carried by INSAT-3D, receives the meteorological, hydrological, oceanographic parameters sent by Automatic Data Collection platforms located at remote uninhabited locations and relays them to a processing center for generating accurate weather forecasts. 

INSAT-3D is also equipped with a search and rescue payload that picks up and relays alert signals originating from the distress beacons of maritime, aviation and land based users and relays them to the mission control center to facilitate speedy search and rescue operations. 

ISRO has taken up the responsibility of end-to-end reception and processing of INSAT-3D data and the derivation of meteorological parameters with India Meteorological Department (IMD), New Delhi. 

An indigenously designed and developed INSAT-3D Meteorological Data Processing System (IMDPS) is installed and commissioned at IMD, New Delhi with a mirror site at Space Applications Centre, Bopal, Ahmedabad.

The satellite will monitor atmospheric characteristics such as cloud motion winds, vertical profiles of humidity and temperature, total precipitable water, sea surface temperature over Indian Ocean, outgoing radiation etc.

INSAT-3D being fueled on July 9, 2013.
INSAT-3D being fueled on July 9, 2013.

INSAT-3D Features

The spacecraft platform is adopted from the standard 12K bus with a power handling capability of around 1100 W.

The satellite is built with a dry mass of 965 kg and lift-off mass of 2060 kg providing a mission life of about seven years.  

The satellite debuts new instruments like the star sensor which is being flown for the first time in Geo-Stationary Earth Orbit and micro stepping Solar Array Drive Assembly to reduce the telecommand / telemetry function of the satellite.

It also incorporates new features of bi-annual rotation and Image and Mirror motion compensations for improved performance of the meteorological payloads.