• The Indian Space Research Organisation (ISRO) and National Aeronautics and Space Administration (NASA) are targeting June 2025 for launch of the NISAR (NASA-ISRO Synthetic Aperture Radar) satellite mission.

• The mission will measure changes in the planet’s terrestrial ecosystems, growth and retreat of its ice sheets, glaciers, and sea ice, and deformation of its crust. 

• Launch services will be provided by ISRO, using the Geosynchronous Launch Vehicle Mark II rocket that will carry the spacecraft into low Earth orbit from the Satish Dhawan Space Centre in Sriharikota.

What is NISAR?

• The NASA-ISRO Synthetic Aperture Radar (NISAR) is a joint Earth-observing mission between NASA and ISRO with the goal to make global measurements of the causes and consequences of land surface changes using advanced radar imaging.

• On September 30, 2014, NASA and ISRO signed a partnership to collaborate on and launch NISAR. 

• NISAR is planned to launch in 2024 from Satish Dhawan Space Center in Sriharikota into a near-polar orbit.

• The NISAR satellite is designed to observe and take measurements of some of the planet’s most complex processes. These include ecosystem disturbances, ice-sheet collapse, and natural hazards such as earthquakes, tsunamis, volcanoes and landslides.

• NISAR is the first satellite mission to collect radar data in two microwave bandwidth regions, called the L-band and the S-band, to measure changes in our planet's surface less than a centimeter across. 

• This allows the mission to observe a wide range of Earth processes, from the flow rates of glaciers and ice sheets to the dynamics of earthquakes and volcanoes.

• NASA is providing the mission’s L-band synthetic aperture radar, a high-rate communication subsystem for science data, GPS receivers, a solid-state recorder and payload data subsystem. ISRO is providing the spacecraft bus, the S-band radar, the launch vehicle and associated launch services.

• NISAR uses a sophisticated information-processing technique known as synthetic aperture radar (SAR) to produce extremely high-resolution images. Radar penetrates clouds and darkness, enabling NISAR to collect data day and night in any weather. 

• The NISAR radar satellite mission will offer detailed insights into two types of ecosystems — forests and wetlands — vital to naturally regulating the greenhouse gases in the atmosphere that are driving global climate change.

• When in orbit, NISAR’s sophisticated radar systems will scan nearly all of Earth’s land and ice surfaces twice every 12 days. 

• The data it collects will help researchers understand two key functions of both ecosystem types — the capture and the release of carbon.

• Forests hold carbon in the wood of their trees, wetlands store it in their layers of organic soil. Disruption of either system, whether gradual or sudden, can accelerate the release of carbon dioxide and methane into the atmosphere.

• Tracking these land-cover changes on a global scale will help researchers study the impacts on the carbon cycle, the processes by which carbon moves between the atmosphere, land, ocean, and living things.

(The author is a trainer for Civil Services aspirants.)