After seven years of design and groundwork, India will finally put into space Insat-3D, an advanced weather satellite configured with improved imaging system and atmospheric sounder, from Kourou, French Guiana. This will be the first geostationary sounder system over Indian Ocean. With Kalpana and Insat-3A already operational in geostationary orbit for the past decade at 74 degree East and 93.5 degree East respectively, sources said, Insat-3D will add a new dimension to weather monitoring. Kalpana and Insat-3A have imaging systems providing images in visible, near-infrared, shortwave infrared, water vapour and thermal infrared bands. A well-placed source in Indian Space Research Organisation (ISRO) said Insat-3D will have weather monitoring through its atmospheric sounding system, which provides vertical profiles of temperature (40 levels from surface to -70 km), humidity (21 levels from surface to -15 km) and integrated ozone from surface to top of the atmosphere. The imaging system of Insat-3D has significant improvements over its predecessors. It is equipped with imaging in middle infrared band to provide night-time pictures of low clouds and fog; imaging in two thermal-infrared bands for estimation of sea surface temperature (SST) with better accuracy and higher spatial resolution in the visible and thermal-infrared bands. The source said that Insat-3D will also carry a Data Relay Transponder and Search and Rescue Transponder. Stating that it will provide continuity to earlier missions and further augment the capability to provide various meteorological as well as search and rescue services, the source said it has a lift-off mass of 2,060 kg, which includes about 1,125 kg of propellant. The propellant carried is mainly required to raise the satellite from the Geosynchronous Transfer Orbit (GTO) to its final Geostationary Orbit and to maintain the satellite attitude during its life. Insat-3D is based on ISRO’s “two-tonne class” platform (I-2K bus) employing light-weight structural elements like Carbon Fibre Reinforced Plastic (CFRP). It will be launched into a GTO by Ariane-5 VA-214 launch vehicle, a solar panel will be deployed immediately after its injection into GTO. Following this, Isro’s Master Control Facility (MCF) at Hassan takes control of the satellite and performs the initial orbit raising manoeuvres using the Liquid Apogee Motor (LAM) on-board the satellite, finally placing it in the circular Geostationary Orbit. Later, it will be put into its final orbital configuration and positioned at 82 deg East longitude.
Source: Deccan Herald