Relevance for UPSC: GS Paper III – Science & Technology, Disaster Management
Source: The Hindu; NASA–ISRO updates

The NASA–ISRO Synthetic Aperture Radar (NISAR) mission will be declared operational on November 7, 2025, after completing its in-orbit testing phase. Launched jointly by NASA and ISRO, NISAR represents one of the most advanced Earth-observation collaborations, designed to study dynamic changes on the planet’s surface with unprecedented precision.

About NISAR

Type: Dual-frequency Earth-observation radar satellite.
Orbit: Sun-synchronous, with a 12-day global mapping cycle.
Objective: To monitor Earth’s surface deformation, ecosystems, and climate changes.

Key Components:

• L-band Synthetic Aperture Radar (SAR) – developed by NASA.
• S-band SAR – developed by ISRO.
• Large Deployable Antenna Reflector (~12 m) – one of the largest of its kind for Earth science missions.

How it works: Uses Synthetic Aperture Radar, which emits microwave signals and measures their reflections, allowing it to capture high-resolution images day or night, and through clouds or smoke.

Functions and Applications

• Disaster Management: Detects earthquakes, volcanic activity, landslides, and flood patterns, supporting rapid emergency response.
• Cryosphere Monitoring: Tracks glacier and ice sheet movement, crucial for understanding sea-level rise.
• Environmental Studies: Monitors deforestation, forest biomass, soil deformation, and land-use changes, helping evaluate carbon storage and climate resilience.
• Agriculture and Water Resources: Assesses soil moisture, crop patterns, and aquifer stress, aiding precision agriculture.
• Coastal Studies: The S-band radar enhances observation of shorelines, wind patterns, and ocean currents for blue economy applications.

NISAR transforms Earth observation into a real-time science — mapping our planet’s motion, resources, and resilience with unmatched precision.

UPSC Prelims Practice Question

With reference to the NISAR mission, which of the following statements are correct?

1. It uses L-band and S-band Synthetic Aperture Radar to map Earth every 12 days.
2. It cannot operate at night or during cloudy conditions.
3. It can detect ground deformation as small as a few centimeters.

Select the correct code:
(a) 1 only  (b) 1 and 3 only  (c) 2 and 3 only  (d) 1, 2 and 3

Answer: (b) 1 and 3 only