In a groundbreaking partnership agreement signed in 2014, the space agencies of the United States and India collaborated to create the first radar of its kind in space: the NASA-ISRO Synthetic Aperture Radar, or NISAR. Expected to launch from the Satish Dhawan Space Centre in January 2024, NISAR will operate in a near-polar orbit and will be the first satellite to systematically map the Earth using two different radar frequencies, L-band and S-band.

 

At 2,800 kilograms, NISAR is a Low Earth Orbit (LEO) observatory that will map the entire globe in just 12 days. The satellite consists of both L-band and S-band Synthetic Aperture Radar (SAR) instruments, making it a dual-frequency imaging radar satellite. NASA provided the L-band radar, GPS, a high-capacity solid-state recorder to store data, and a payload data subsystem, while ISRO provided the S-band radar, the Geosynchronous Satellite Launch Vehicle (GSLV) launch system, and spacecraft.

 

The S-band radar operates on a wavelength of 8-15 cm and a frequency of 2-4 GHz, which makes it useful for near and far-range weather observation. Meanwhile, the L-band radar will be used for global science operations for at least three years, while ISRO will utilize the S-band radar for a minimum of five years. NISAR also features a 39-foot stationary antenna reflector, made of a gold-plated wire mesh, that will focus "the radar signals emitted and received by the upward-facing feed on the instrument structure.

 

One of the most remarkable features of NISAR is its ability to produce high-resolution images by using SAR technology. Unlike traditional optical sensors, SAR can penetrate clouds and can collect data day and night, regardless of weather conditions. This capability will enable NISAR to provide a wealth of data and information about the Earth's surface changes, natural hazards, and ecosystem disturbances, helping to advance our understanding of Earth system processes and climate change.

 

The benefits of NISAR are far-reaching and diverse. The mission will provide critical information to help manage natural disasters such as earthquakes, tsunamis, and volcanic eruptions, enabling faster response times and better risk assessments. It will also provide data for infrastructure monitoring and management, such as monitoring of oil spills, urbanization, and deforestation. Additionally, NISAR data will be used to improve agriculture management and food security by providing information about crop growth, soil moisture, and land-use changes.

 

Finally, NISAR will help to monitor and understand the impacts of climate change on the Earth's land surface, including melting glaciers, sea-level rise, and changes in carbon storage. As the first satellite of its kind, NISAR represents a revolutionary step forward in Earth observation and will provide unprecedented insights into our planet's surface and climate.

 

Image: NASA