INSAT 3D

INSAT-3D is an advanced Indian meteorological satellite launched by the Indian Space Research Organisation (ISRO) to provide enhanced weather observation and forecasting capabilities. Part of the Indian National Satellite System (INSAT) series, it was designed specifically for continuous monitoring of the atmosphere, land, and ocean, and for supporting disaster management through timely data delivery. The satellite carries advanced payloads for meteorology, imaging, and data relay, strengthening India’s capacity for climate studies, weather forecasting, and search and rescue operations.

Launch and Mission Overview

• Launch Date: 26 July 2013
• Launch Vehicle: Ariane-5 rocket
• Launch Site: Kourou, French Guiana
• Orbit: Geostationary orbit at 82° East longitude
• Mission Life: Designed for around 7 years, with extensions possible depending on performance

INSAT-3D was launched as a successor to the earlier INSAT-3A and KALPANA-1 satellites, providing more advanced instruments for Earth observation and meteorology.

Payloads and Instruments

INSAT-3D carries a combination of imaging and sounder instruments, along with supporting systems:

1. Imager:
   • A six-channel multi-spectral camera that captures images in visible, shortwave infrared, mid-infrared, water vapour, and thermal infrared bands.
   • Provides data for cloud motion, cyclone detection, fog monitoring, sea surface temperature, and vegetation analysis.
2. Sounder:
   • A 19-channel atmospheric sounder designed to profile temperature and humidity at different atmospheric layers.
   • Helps in vertical profiling of the atmosphere for weather prediction models.
3. Data Relay Transponder (DRT):
   • Collects and relays data from Automatic Weather Stations (AWS), Automatic Rain Gauges (ARGs), and other ground-based platforms.
4. Satellite Aided Search and Rescue (SAS&R):
   • Supports the international Cospas–Sarsat programme.
   • Detects and relays signals from distress beacons for maritime, aeronautical, and land-based emergencies, coordinated through the Indian Mission Control Centre.

Key Applications

• Weather Forecasting: Provides high-resolution images and atmospheric profiles essential for short-range and medium-range forecasts.
• Cyclone Monitoring: Detects cyclogenesis in the Indian Ocean, tracks cyclone paths, and predicts landfall with higher accuracy.
• Monsoon Studies: Assists in tracking monsoon clouds, rainfall patterns, and associated climatic variations.
• Disaster Management: Supports early warnings for floods, storms, and droughts through real-time monitoring.
• Oceanographic Applications: Monitors sea surface temperature and ocean circulation patterns critical for fisheries and climate studies.
• Search and Rescue Operations: Facilitates emergency response through its SAS&R payload.

Advantages

• Improved Accuracy: Multi-spectral imaging and sounder data provide more precise atmospheric parameters compared to earlier satellites.
• Continuous Coverage: Geostationary positioning enables round-the-clock monitoring of the Indian subcontinent and surrounding oceans.
• Integration with Ground Systems: Works with a dense network of ground-based AWS and ARG stations, enhancing localised forecasting.
• International Contribution: Supports global weather and SAR networks by providing data relevant beyond India’s boundaries.

Significance

INSAT-3D marked a technological advancement for India’s meteorological satellite programme, combining imaging and sounding instruments in a single platform. It has been crucial for monitoring severe weather systems over the Bay of Bengal and the Arabian Sea, improving cyclone warnings, and supporting disaster management authorities. Its role in the Cospas–Sarsat search and rescue system also highlights its humanitarian contribution.