Synthetic Aperture Radar (SAR)

Synthetic Aperture Radar (SAR) : Recently, marking a significant milestone in Earth observation, the NASA-ISRO Synthetic Aperture Radar (NISAR) satellite arrived at India’s spaceport in Sriharikota.

• Aboout SAR: A state-of-the-art radar-based imaging system capable of capturing high-resolution images regardless of lighting or weather conditions.

o Uses microwave pulses and captures returning echoes from surfaces like land, water, ice, and cities.

o All-Weather, 24/7 Monitoring: Can operate through clouds, smoke, haze, and light rain, making it ideal for continuous Earth observation both day and night.

o Wide-Area Coverage: Can scan large areas — often hundreds of kilometers wide — in a single pass, enabling efficient monitoring of vast regions.

o Surface Composition Detection Detects surface types and subtle changes by sensing differences in microwave reflections, unlike optical sensors.

• About NISAR Mission: A collaborative Earth observation mission between NASA and ISRO, established under a 2014 bilateral agreement.

o Set to launch in June 2025 from the Satish Dhawan Space Centre, Andhra Pradesh, aboard ISRO’s GSLV Mk II rocket.

o It is the first radar-based Earth observation mission jointly developed by the U.S. and India.

o Map the Earth’s entire surface every 12 days, allowing for frequent & accurate observations.

o Monitoring Objectives: It will track ecosystem shifts, ice sheet movements, vegetation growth, sea level rise, and groundwater changes.

o Disaster and Hazard Detection: The mission will help monitor and assess natural hazards like earthquakes, volcanic activity, tsunamis, and landslides.