NISAR Satellite Set for Launch on July 30, Pg 12.

Key Highlights:

• NISAR is the world’s first Earth observation satellite to use dual-frequency SAR (L-band by NASA and S-band by ISRO).
• Weighing 2,392 kg, it will be placed in a 743-km sun-synchronous orbit using the GSLV-F16 launch vehicle.
• Features a 12-metre unfurlable mesh antenna, deployed 9 metres from the satellite.
• Capable of all-weather, day-and-night observation with a revisit time of 12 days and 242 km swathe using SweepSAR technology.
• Mission life is five years, with scientific and disaster management applications.
• Data applications include ground deformation, ice sheet dynamics, soil moisture, vegetation change, sea ice, and disaster response.

Detailed Insights:

• NISAR represents a landmark India-US space collaboration, enhancing Earth system science.
• The mission is divided into four phases:
• Launch phase: GSLV-F16 injects satellite into orbit.
• Deployment phase: Unfurlable antenna deployed using a multistage deployable boom.
• Commissioning phase (first 90 days): Calibration and checkout of satellite and instruments.
• Science phase: Full-scale operations, orbit maintenance, and calibration/validation activities.
• Data will be crucial for climate research, agriculture, resource mapping, and resilience planning in disaster-prone regions.
• Enhances India’s indigenous EO (Earth Observation) capabilities with advanced radar imaging from dual frequencies.

Concepts Involved:

• Synthetic Aperture Radar (SAR): Radar system that creates high-resolution images by using the motion of the satellite.
• SweepSAR: Advanced SAR mode providing wide swath coverage with high resolution.
• Sun-synchronous orbit: Polar orbit allowing satellite to pass over the same part of Earth at the same local solar time.
• L-band and S-band: Radar frequencies used to penetrate clouds, vegetation, and soil layers, enhancing detection of ground changes.