Model Answer
0 min readIntroduction
Indian Remote Sensing (IRS) satellites constitute a comprehensive system for remote sensing of the Earth’s surface. Initiated in 1988 with the launch of IRS-1A, the program has significantly contributed to India’s self-reliance in Earth observation technology. These satellites, developed and operated by the Indian Space Research Organisation (ISRO), provide crucial data for a wide range of applications including resource monitoring, disaster management, urban planning, and agricultural assessment. The IRS series has evolved over the years, incorporating advanced technologies and catering to increasingly specific user needs.
Evolution and Categorization of IRS Satellites
The IRS program can be broadly categorized into several generations, each with distinct characteristics:
- First Generation (IRS-1A, 1B, 1C, 1D): Launched between 1988 and 1997, these satellites primarily focused on providing data for resource monitoring with coarse to medium spatial resolution. IRS-1A was a landmark achievement, providing continuous data for over a decade.
- Second Generation (IRS-P series – P2, P3, P4 (OceanSat-1), P5 (CartoSat-1), P6 (Resourcesat-1)): This generation, launched from 1996 onwards, introduced more advanced sensors and capabilities. OceanSat-1 focused on oceanographic studies, while CartoSat-1 provided high-resolution imagery for cartographic applications.
- Third Generation (CartoSat-2, 2A, 2B, 2C, 2D, 2E, Resourcesat-2, 2A, OceanSat-2): These satellites, launched from 2006 onwards, represent a significant leap in terms of spatial resolution and data accuracy. They feature panchromatic sensors capable of sub-meter resolution.
- Fourth Generation (RISAT series, Oceansat-3): The RISAT series utilizes Synthetic Aperture Radar (SAR) technology, enabling all-weather, day-and-night imaging. Oceansat-3 carries an Ocean Colour Monitor (OCM) and Sea Surface Temperature (SST) sensors.
Key Characteristics & Payloads
IRS satellites share several common characteristics:
- Sun-Synchronous Polar Orbit: Most IRS satellites are placed in a sun-synchronous polar orbit at an altitude of around 600-800 km. This orbit ensures consistent lighting conditions for imaging, facilitating data comparison over time.
- Multi-Spectral Sensors: They carry a variety of multi-spectral sensors that capture data in different wavelengths of the electromagnetic spectrum. This allows for the identification of various surface features based on their spectral signatures.
- High Geometric Accuracy: IRS satellites are designed to provide data with high geometric accuracy, essential for mapping and GIS applications.
Common Payloads:
- PAN (Panchromatic): Captures data in a single broad band, providing high spatial resolution imagery.
- LISS (Linear Imaging Self Scanning): A series of multi-spectral sensors with varying spatial resolutions (LISS-I, LISS-II, LISS-III, LISS-IV).
- MSS (Multi-Spectral Scanner): Used in earlier generations for broad-area coverage.
- Ocean Colour Monitor (OCM): Used in Oceansat series for ocean studies.
- Synthetic Aperture Radar (SAR): Used in RISAT series for all-weather imaging.
Applications of IRS Satellite Data
IRS satellite data finds applications in a diverse range of sectors:
- Agriculture: Crop monitoring, yield estimation, drought assessment, and precision farming.
- Forestry: Forest cover mapping, deforestation monitoring, and biodiversity assessment.
- Water Resources: Water body mapping, flood monitoring, and groundwater prospecting.
- Urban Planning: Urban sprawl analysis, infrastructure planning, and disaster vulnerability assessment.
- Disaster Management: Flood mapping, cyclone tracking, earthquake damage assessment, and forest fire monitoring.
- Oceanography: Sea surface temperature monitoring, ocean current mapping, and coastal zone management.
- Geology: Geological mapping, mineral exploration, and landslide hazard assessment.
Recent Developments
Recent developments include the launch of RISAT-2BR2 and RISAT-2B2 in 2019, enhancing India’s surveillance capabilities. The launch of Oceansat-3 in 2022 further improved ocean observation capabilities. ISRO is continuously working on developing next-generation IRS satellites with even higher resolution and advanced sensors.
| Satellite | Resolution (Panchromatic) | Key Application |
|---|---|---|
| IRS-1A | 36.25 m | Resource Monitoring |
| CartoSat-1 | 5.8 m | Cartography |
| CartoSat-2E | 0.8 m | High-Resolution Imaging |
| RISAT-2BR2 | 0.5 m (SAR) | All-Weather Surveillance |
Conclusion
The Indian Remote Sensing satellite program has been a resounding success, providing invaluable data for a wide range of applications and contributing significantly to India’s socio-economic development. Continuous advancements in sensor technology, orbital configurations, and data processing techniques are ensuring that the IRS series remains at the forefront of Earth observation capabilities. Future satellites will likely incorporate even more sophisticated sensors and data analytics tools, further enhancing their utility and impact.
Answer Length
This is a comprehensive model answer for learning purposes and may exceed the word limit. In the exam, always adhere to the prescribed word count.